1.
Mandrill
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The mandrill is a primate of the Old World monkey family. It is one of two assigned to the genus Mandrillus, along with the drill. Both the mandrill and the drill were once classified as baboons in the genus Papio, although they look superficially like baboons, they are more closely related to Cerocebus mangabeys. Mandrills are found in southern Cameroon, Gabon, Equatorial Guinea, mandrills mostly live in tropical rainforests. They live in large groups. Mandrills have a diet consisting mostly of fruits and insects. Their mating season peaks in July to September, with a birth peak in December to April. Mandrills are the worlds largest monkeys, charles Darwin wrote in The Descent of Man that no other member in the whole class of mammals is coloured in so extraordinary a manner as the adult male mandrills. The mandrill is classified as vulnerable by IUCN, the mandrill has an olive green or dark grey pelage with yellow and black bands and a white belly. Its hairless face has a muzzle with distinctive characteristics, such as a red stripe down the middle. It also has red nostrils and lips, a yellow beard, the areas around the genitals and the anus are multi-colored, being red, pink, blue, scarlet, and purple. They also have pale pink ischial callosities, the coloration of the animal is more pronounced in dominant adult males. Both sexes have chest glands, which are used in olfactory communication and these, too, are more prominent in dominant adult males. Males also have longer canines than females, with an average of 4.5 cm and 1.0 cm, the mandrill is one of the most sexually dimorphic mammals due to extremely strong sexual selection which favors males in both size and coloration. Males typically weigh 19–37 kg, with a mass of 32.3 kg. Females weigh roughly half as much as the male, at 10–15 kg, exceptionally large males can weigh up to 54 kg, with unconfirmed reports of outsized mandrills weighing 60 kg per the Guinness Book of World Records. The average male is 75–95 cm long and the female is 55–66 cm, the shoulder height while on all fours can range from 45–50 cm in females and 55–65 cm in males. Compared to the largest baboons, the mandrill is more ape-like in structure, with a muscular and compact build, shorter, thicker limbs that are longer in the front, mandrills can live up to 31 years in captivity
2.
Chuck (engineering)
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A chuck is a specialized type of clamp. It is used to hold an object with symmetry, especially a cylinder. In drills and mills it holds the rotating tool whereas in lathes it holds the rotating workpiece, on a lathe the chuck is mounted on the spindle which rotates within the headstock. For some purposes an additional chuck may be mounted on the non-rotating tailstock, many chucks have jaws, that are arranged in a radially symmetrical pattern like the points of a star. The jaws are tightened up to hold the tool or workpiece, often the jaws will be tightened or loosened with the help of a chuck key, which is a wrench-like tool made for the purpose. Many jawed chucks, however, are of the keyless variety, some lathe chucks have independently moving jaws which can also hold irregularly shaped objects. Collet chucks, rather than having jaws, have collets, which are flexible collars or sleeves that fit closely around the tool or workpiece and grip it when squeezed. A few chuck designs are more complex yet, and they involve specially shaped jaws, higher numbers of jaws, quick-release mechanisms, some chucks, such as magnetic chucks and vacuum chucks, are of a different sort from the radially symmetrical mechanical clamps mentioned above. Instead, they may be surfaces against which workpieces or tools are held by magnetic or vacuum force. To chuck a tool or workpiece is to hold it with a chuck, lathe work whose workholding involves chucking individual slugs or blanks is often called chucking work, in contrast to bar work or bar feed work. In bar work the bar protrudes from the chuck, is worked upon, automatic lathes that specialize in chucking work are often called chuckers. A self-centering chuck, also known as a chuck, uses dogs, interconnected via a scroll gear. Because they most often have three jaws, the term three-jaw chuck without other qualification is understood by machinists to mean a self-centering three-jaw chuck, the term universal chuck also refers to this type. These chucks are best suited to grip circular or hexagonal cross-sections when very fast, sometimes this type of chuck has 4 or 6 jaws instead of 3. More jaws grip the more securely if it is truly cylindrical. Four jaws are also useful for square bar work, there are also independent-jaw chucks with three jaws. There are hybrid self-centering chucks that have adjustment screws that can be used to improve the concentricity after the workpiece has been gripped by the scroll jaws. This feature is meant to combine the speed and ease of the scroll plates self-centering with the run-out eliminating controllability of an independent-jaw chuck, the most commonly used name for this type is a brand name, Set-Tru
3.
Lathe
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Lathes are used in woodturning, metalworking, metal spinning, thermal spraying, parts reclamation, and glass-working. Lathes can be used to shape pottery, the design being the potters wheel. Most suitably equipped metalworking lathes can also be used to produce most solids of revolution, plane surfaces, ornamental lathes can produce three-dimensional solids of incredible complexity. The workpiece is held in place by either one or two centers, at least one of which can typically be moved horizontally to accommodate varying workpiece lengths. Other work-holding methods include clamping the work about the axis of rotation using a chuck or collet, or to a faceplate, using clamps or dogs. Examples of objects that can be produced on a lathe include candlestick holders, gun barrels, cue sticks, table legs, bowls, baseball bats, musical instruments, crankshafts, and camshafts. The lathe is an ancient tool, dating at least to ancient Egypt and known to be used in Assyria, the lathe was very important to the Industrial Revolution. It is known as the mother of machine tools, as it was the first machine tool that lead to the invention of other machine tools, the origin of turning dates to around 1300 BCE when the Ancient Egyptians first developed a two-person lathe. One person would turn the work piece with a rope while the other used a sharp tool to cut shapes in the wood. Ancient Rome improved the Egyptian design with the addition of a turning bow, in the Middle Ages a pedal replaced hand-operated turning, allowing a single person to rotate the piece while working with both hands. The pedal was usually connected to a pole, often a straight-grained sapling, the system today is called the spring pole lathe. Spring pole lathes were in use into the early 20th century. An important early lathe in the UK was the boring machine that was installed in 1772 in the Royal Arsenal in Woolwich. It was horse-powered and allowed for the production of more accurate. One of the key characteristics of this machine was that the workpiece was turning as opposed to the tool, henry Maudslay who later developed many improvements to the lathe worked at the Royal Arsenal from 1783 being exposed to this machine in the Verbruggen workshop. During the Industrial Revolution, mechanized power generated by water wheels or steam engines was transmitted to the lathe via line shafting, allowing faster and easier work, metalworking lathes evolved into heavier machines with thicker, more rigid parts. Between the late 19th and mid-20th centuries, individual electric motors at each lathe replaced line shafting as the power source, today manually controlled and CNC lathes coexist in the manufacturing industries. A lathe may or may not have legs, which sit on the floor, a lathe may be small and sit on a workbench or table, not requiring a stand
4.
Exhaust system
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An exhaust system is usually piping used to guide reaction exhaust gases away from a controlled combustion inside an engine or stove. The entire system conveys burnt gases from the engine and includes one or more exhaust pipes, depending on the overall system design, the exhaust gas may flow through one or more of, Cylinder head and exhaust manifold A turbocharger to increase engine power. A catalytic converter to reduce air pollution, a muffler / silencer, to reduce noise. An exhaust pipe must be designed to carry toxic and/or noxious gases away from the users of the machine. Also, the gases from most types of machines are hot, the pipe must be heat-resistant. A chimney serves as an exhaust pipe in a stationary structure, for the internal combustion engine it is important to have the exhaust system tuned for optimal efficiency. Also this should meet the regulation norms maintained in each country, in China, China 5, In European countries, EURO5, In India, BS-4, etc. In most motorcycles all or most of the exhaust system is visible, aftermarket exhausts may be made from steel, aluminium, titanium, or carbon fiber. Motorcycle exhausts come in many varieties depending on the type of engine, a twin cylinder may flow its exhaust into separate exhaust sections, such as seen in the Kawasaki EX250. Or, they may flow into a single exhaust section known as a two-into-one, larger engines that come with 4 cylinders, such as Japanese super-sport or super-bikes often come with a twin exhaust system. A full system may be bought as an accessory, also called a 4-2-1 or 4-1. In the past, these bikes would come standard with a single exhaust, however, EU noise and pollution regulations have generally stopped this practice, forcing companies to use other methods to increase performance of the motorcycle. A 2-stroke exhaust can be made to be quieter than 70dBa at 6000 rpm without sacrificing any power gains, additionally, the nature of the beast is that a 4T exhaust note above 6000 rpm is unduly harsh to the human ear. In many trucks / lorries all or most of the exhaust system is visible, often in such trucks the silencer is surrounded by a perforated metal sheath to avoid people getting burnt touching the hot silencer. This sheath may be plated as a display feature. Part of the pipe between the engine and the silencer is often flexible metal industrial ducting, this helps to avoid vibration from the engine being transferred into the exhaust system and this provides greater power and fuel efficiency. With an onboard diesel or petrol engine below-decks on marine vessels, feeding water into the exhaust pipe cools the exhaust gas and thus lessens the back-pressure at the engines cylinders. Often in marine service the exhaust manifold is integral with a heat exchanger which allows sea water to cool a system of fresh water circulating within the engine
5.
Jewelry
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Jewellery or jewelry consists of small decorative items worn for personal adornment, such as brooches, rings, necklaces, earrings, and bracelets. Jewellery may be attached to the body or the clothes, for many centuries metal, often combined with gemstones, has been the normal material for jewellery, but other materials such as shells and other plant materials may be used. It is one of the oldest type of archaeological artefact – with 100, historically, the most widespread influence on jewellery in terms of design and style have come from Asia. Jewellery may be made from a range of materials. Gemstones and similar such as amber and coral, precious metals, beads, and shells have been widely used. In most cultures jewellery can be understood as a symbol, for its material properties, its patterns. Jewellery has been made to nearly every body part, from hairpins to toe rings. The word jewellery itself is derived from the jewel, which was anglicised from the Old French jouel. In British English, Indian English, New Zealand English, Hiberno-English, Australian English, both are used in Canadian English, though jewelry prevails by a two to one margin. Numerous cultures store wedding dowries in the form of jewellery or make jewellery as a means to store or display coins, alternatively, jewellery has been used as a currency or trade good, an example being the use of slave beads. Many items of jewellery, such as brooches and buckles, originated as functional items. Jewellery can also symbolise group membership or status, wearing of amulets and devotional medals to provide protection or ward off evil is common in some cultures. These may take the form of symbols, stones, plants, animals, body parts, in creating jewellery, gemstones, coins, or other precious items are often used, and they are typically set into precious metals. Alloys of nearly every metal known have been encountered in jewellery, bronze, for example, was common in Roman times. Modern fine jewellery usually includes gold, white gold, platinum, palladium, titanium, most contemporary gold jewellery is made of an alloy of gold, the purity of which is stated in karats, indicated by a number followed by the letter K. American gold jewellery must be of at least 10K purity, many whimsical fashions were introduced in the extravagant eighteenth century. Cameos that were used in connection with jewellery were the attractive trinkets along with many of the objects such as brooches, ear-rings. Some of the necklets were made of pieces joined with the gold chains were in and bracelets were also made sometimes to match the necklet
6.
Double reed
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A double reed is a type of reed used to produce sound in various wind instruments. The term double reed comes from the fact there are two pieces of cane vibrating against each other. A single reed consists of one piece of cane which vibrates against a mouthpiece made of metal, hardened rubber, resin, the term double reeds can also refer collectively to the class of instruments which use double reeds. There are several differences, the most obvious being size, between various types of reeds, for example between that for a bassoon and that for an oboe or a cor anglais. Typically, Arundo donax cane is used for the making of double reeds, for bassoon reeds, tubes of this cane are first split lengthwise then gouged to a certain thickness. The chosen piece of cane is cut to shape and the centre portion is thinned. The cane is folded end to end to form the two blades of the reed, the unprofiled end of the cane is shaped into a tube with the aid of a mandrel and bound with three strategically placed wires. A turban made out of thread is added on the third wire and it provides a hand hold for the reed that isnt a sharp wire. The folded tip is cut off to allow the blades to vibrate and final adjustments to the interior of the using a reamer. The reed is then ready to fit to the bocal of the bassoon, note that there are many schools of thought and processes for making reeds. However, because the oboe does not have a bocal, the cane must be fastened to a metal tube, the staple is then inserted into the farrow at the upper end of the oboe. There are many different methods of making reeds and many variations of design have been developed, players can buy reeds either ready-made, or in various stages of formation, such as part-scraped, reed blanks, or buy the staples and cane separately. Cane is sold in forms, as tubes, gouged, gouged and shaped. Bassoon cane has the option of being profiled before purchase. Cane from several different regions is used in reed making, traditionally from southern France, there are also many options with regard to staples, shaping equipment, and so forth, which all have a subtle effect on the tone quality a reed will produce. While cane is by far the most common material for double reeds, reeds made out of synthetic materials may be used, these reeds often last longer and are less sensitive to temperature and humidity flucutations. Most reeds produced from synthetic materials have a quality that is dissimilar to that of a cane reed and are not favored by musicians. However, some recent manufacturers produce synthetic reeds that are used in a professional setting, oboe double reeds are about 7 mm in width
7.
Cylinder
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In its simplest form, a cylinder is the surface formed by the points at a fixed distance from a given straight line called the axis of the cylinder. It is one of the most basic curvilinear geometric shapes, commonly the word cylinder is understood to refer to a finite section of a right circular cylinder having a finite height with circular ends perpendicular to the axis as shown in the figure. If the ends are open, it is called an open cylinder, if the ends are closed by flat surfaces it is called a solid cylinder. The formulae for the area and the volume of such a cylinder have been known since deep antiquity. The area of the side is known as the lateral area. An open cylinder does not include either top or bottom elements, the surface area of a closed cylinder is made up the sum of all three components, top, bottom and side. Its surface area is A = 2πr2 + 2πrh = 2πr = πd=L+2B, for a given volume, the closed cylinder with the smallest surface area has h = 2r. Equivalently, for a surface area, the closed cylinder with the largest volume has h = 2r. Cylindric sections are the intersections of cylinders with planes, for a right circular cylinder, there are four possibilities. A plane tangent to the cylinder meets the cylinder in a straight line segment. Moved while parallel to itself, the plane either does not intersect the cylinder or intersects it in two line segments. All other planes intersect the cylinder in an ellipse or, when they are perpendicular to the axis of the cylinder, a cylinder whose cross section is an ellipse, parabola, or hyperbola is called an elliptic cylinder, parabolic cylinder, or hyperbolic cylinder respectively. Elliptic cylinders are also known as cylindroids, but that name is ambiguous, as it can also refer to the Plücker conoid. The volume of a cylinder with height h is V = ∫0 h A d x = ∫0 h π a b d x = π a b ∫0 h d x = π a b h. Even more general than the cylinder is the generalized cylinder. The cylinder is a degenerate quadric because at least one of the coordinates does not appear in the equation, an oblique cylinder has the top and bottom surfaces displaced from one another. There are other unusual types of cylinders. Let the height be h, internal radius r, and external radius R, the volume is given by V = π h
8.
Drill
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The attachment is gripped by a chuck at one end of the drill and rotated while pressed against the target material. The tip, and sometimes edges, of the tool does the work of cutting into the target material. This may be slicing off thin shavings, grinding off small particles, crushing and removing pieces of the workpiece, countersinking, counterboring, drills are commonly used in woodworking, metalworking, construction and do-it-yourself projects. Specially designed drills are used in medicine, space missions. Drills are available with a variety of performance characteristics, such as power. Around 35,000 BC, Homo sapiens discovered the benefits of the application of rotary tools and this would have rudimentarily consisted of a pointed rock being spun between the hands to bore a hole through another material. This led to the drill, a smooth stick, that was sometimes attached to flint point. This was used by ancient civilizations around the world including the Mayans. The earliest perforated artifacts, such as bone, ivory, shells, bow drill are the first machine drills, as they convert a back-and forth motion to a rotary motion, and they can be traced back to around 10,000 years ago. It was discovered that tying a cord around a stick, and then attaching the ends of the string to the ends of a stick, allowed a user to drill quicker, mainly used to create fire, bow-drills were also used in ancient woodwork, stonework and dentistry. There are hieroglyphs depicting Egyptian carpenters and bead makers in a tomb at Thebes using bow-drills, the earliest evidence of these tools being used in Egypt dates back to around 2500 BCE. The usage of bow-drills was widely spread through Europe, Africa, Asia and North America, over the years many slight variations of bow and strap drills have developed for the various uses of either boring through materials or lighting fires. The core drill was developed in ancient Egypt by 3000 BC, the pump drill was invented during Roman times. It consists of a vertical spindle aligned by a piece of horizontal wood, the hollow-borer tip, first used around the 13th century, consisted of a stick with a tubular shaped piece of metal on the end, such as copper. This allowed a hole to be drilled while only actually grinding the outer section of it and this completely separates the inner stone or wood from the rest, allowing the drill to pulverize less material to create a similarly sized hole. The auger allowed for more torque for larger holes and it is uncertain when the Brace and Bit was invented, however, the earliest picture found so far dates from the 15th century. It is a type of hand crank drill that consists of two parts as seen in the picture, the brace, on the upper half, is where the user holds and turns it and on the lower part is the bit. The bit is interchangeable as bits wear down, the auger uses a rotating helical screw similar to the Archimedean screw-shaped bit that is common today
9.
Washer (hardware)
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A washer is a thin plate with a hole that is normally used to distribute the load of a threaded fastener, such as a screw or nut. Other uses are as a spacer, spring, wear pad, preload indicating device, locking device, Washers usually have an outer diameter about twice larger than their inner diameter. Washers are usually metal or plastic, high-quality bolted joints require hardened steel washers to prevent the loss of pre-load due to Brinelling after the torque is applied. Washers are also important for preventing galvanic corrosion, particularly by insulating steel screws from aluminium surfaces, the origin of the word is unknown, the first recorded use of the word was in 1346, however, the first time its definition was recorded was in 1611. The American National Standards Institute provides standards for general use flat washers, type A is a series of steel washers at broad tolerances, where precision is not critical. Type B is a series of flat washers with tighter tolerances where outside diameters are categorized as narrow, type is not to be confused with form. The British Standard for Metric Series Metal Washers written in 1968 coined the term form, lock washers, locknuts, jam nuts, and thread-locking fluid are ways to prevent vibration from loosening a bolted joint. The term washer is often applied to various types such as those used to seal the control valve in taps. Crush washers are made of a metal such as aluminium or copper and are used to seal fluid or gas connections such as those found in an internal combustion engine. Zinc coating acts as a surface layer that falls victim to corrosive materials before the washers material can be harmed. Cadmium produces a high-quality protective surface but is toxic, both biologically and environmentally, nickel coatings add protection from corrosion only when the finish is dense and non-porous. Electroplating – This method involves coating the washer by electrolytic deposition using metals such as chromium or silver, phosphating – A resilient, but abrasive surface is achieved by incorporating a zinc-phosphate layer and corrosion-protective oil. Browning or bluing – Exposing the washer to a compound or alkali salt solution causes an oxidizing chemical reaction. The integrity of the coating can improved by treating the product with a water-displacing oil. Chemical plating – This technique utilizes a nickel-phosphor alloy that is precipitated onto the surface, creating an extremely corrosion-. Washers of standard sizes are listed in the table below. Measurements in the table refer to the dimensions of the washers as described by the drawing, bit guard Dowel Unified Thread Standard Parmley, Robert. ISBN0070486174 Drawings, designs and discussion of various uses of washers
10.
Brazing
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The filler metal flows into the gap between close-fitting parts by capillary action. The filler metal is slightly above its melting temperature while protected by a suitable atmosphere. It then flows over the metal and is then cooled to join the work pieces together. It is similar to soldering, except for the use of higher temperatures, a major advantage of brazing is the ability to join the same or different metals with considerable strength. High-quality brazed joints require that parts be closely fitted, and the base metals exceptionally clean, in most cases, joint clearances of 0.03 to 0.08 mm are recommended for the best capillary action and joint strength. However, in some brazing operations it is not uncommon to have joint clearances around 0.6 mm, cleanliness of the brazing surfaces is also important, as any contamination can cause poor wetting. The two main methods for cleaning parts, prior to brazing, are cleaning and abrasive or mechanical cleaning. In the case of mechanical cleaning, it is important to maintain the surface roughness as wetting on a rough surface occurs much more readily than on a smooth surface of the same geometry. Another consideration is the effect of temperature and time on the quality of brazed joints, as the temperature of the braze alloy is increased, the alloying and wetting action of the filler metal increases as well. In general, the brazing temperature selected must be above the point of the filler metal. However, several factors influence the joint designers temperature selection, the effect of time on the brazed joint primarily affects the extent to which these effects are present. In general, however, most production processes are selected to minimize brazing time and this is not always the case, however, since in some non-production settings, time and cost are secondary to other joint attributes. Unless brazing operations are contained within an inert or reducing atmosphere environment, the flux also serves the purpose of cleaning any contamination left on the brazing surfaces. Flux can be applied in any number of forms including flux paste, liquid, flux can also be applied using brazing rods with a coating of flux, or a flux core. In either case, the flows into the joint when applied to the heated joint and is displaced by the molten filler metal entering the joint. Excess flux should be removed when the cycle is completed because flux left in the joint can lead to corrosion, impede joint inspection, phosphorus-containing brazing alloys can be self-fluxing when joining copper to copper. Fluxes are generally selected based on their performance on particular base metals, to be effective, the flux must be chemically compatible with both the base metal and the filler metal being used. Self-fluxing phosphorus filler alloys produce brittle phosphides if used on iron or nickel, as a general rule, longer brazing cycles should use less active fluxes than short brazing operations
11.
Screw
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A screw is a type of fastener, sometimes similar to a bolt, typically made of metal, and characterized by a helical ridge, known as a male thread or just thread. A screw is an inclined plane wrapped around a nail, some screw threads are designed to mate with a complementary thread, known as a female thread, often in the form of a nut or an object that has the internal thread formed into it. Other screw threads are designed to cut a groove in a softer material as the screw is inserted. The most common uses of screws are to hold objects together, a screw will usually have a head on one end that contains a specially formed shape that allows it to be turned, or driven, with a tool. Common tools for driving screws include screwdrivers and wrenches, the head is usually larger than the body of the screw, which keeps the screw from being driven deeper than the length of the screw and to provide a bearing surface. The cylindrical portion of the screw from the underside of the head to the tip is known as the shank, the distance between each thread is called the pitch. Another rule is this, curl the fingers of right hand around the screw with your thumb pointing is the direction you want the screw to go. If the screw is right-handed and you turn the screw in the direction of your fingers the screw will move in the direction of your thumb, Screws with left-hand threads are used in exceptional cases. For example, when the screw will be subject to counterclockwise torque, the right side pedal of a bicycle has a left-hand thread. More generally, screw may mean any helical device, such as a clamp, a micrometer, there is no universally accepted distinction between a screw and a bolt. So, as a rule, when buying a packet of screws you would not expect nuts to be included. Part of the confusion over this is due to regional or dialectical differences. An externally threaded fastener which is prevented from being turned during assembly, an externally threaded fastener that has thread form which prohibits assembly with a nut having a straight thread of multiple pitch length is a screw. This distinction is consistent with ASME B18.2.1 and some dictionary definitions for screw, some of these issues are discussed below, ASME standards specify a variety of Machine Screws in diameters ranging up to 0.75 in. These fasteners are used with nuts but also often driven into tapped holes. They might be considered a screw or a bolt based on the Machinerys Handbook distinction, ASME standard B18.2. 1-1996 specifies Hex Cap Screws that range in size from 0. 25–3 in in diameter. These fasteners are very similar to hex bolts and they differ mostly in that they are manufactured to tighter tolerances than the corresponding bolts. Machinerys Handbook refers parenthetically to these fasteners as Finished Hex Bolts, in 1991 responding to an influx of counterfeit fasteners Congress passed PL 101-592 Fastener Quality Act This resulted in the rewriting of specifications by the ASME B18 committee
12.
Electric motor
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An electric motor is an electrical machine that converts electrical energy into mechanical energy. The reverse of this is the conversion of energy into electrical energy and is done by an electric generator. In normal motoring mode, most electric motors operate through the interaction between an electric motors magnetic field and winding currents to generate force within the motor, small motors may be found in electric watches. General-purpose motors with highly standardized dimensions and characteristics provide convenient mechanical power for industrial use, the largest of electric motors are used for ship propulsion, pipeline compression and pumped-storage applications with ratings reaching 100 megawatts. Electric motors may be classified by electric power source type, internal construction, application, type of motion output, perhaps the first electric motors were simple electrostatic devices created by the Scottish monk Andrew Gordon in the 1740s. The theoretical principle behind production of force by the interactions of an electric current. The conversion of energy into mechanical energy by electromagnetic means was demonstrated by the British scientist Michael Faraday in 1821. A free-hanging wire was dipped into a pool of mercury, on which a permanent magnet was placed, when a current was passed through the wire, the wire rotated around the magnet, showing that the current gave rise to a close circular magnetic field around the wire. This motor is often demonstrated in experiments, brine substituting for toxic mercury. Though Barlows wheel was a refinement to this Faraday demonstration. In 1827, Hungarian physicist Ányos Jedlik started experimenting with electromagnetic coils, after Jedlik solved the technical problems of the continuous rotation with the invention of the commutator, he called his early devices electromagnetic self-rotors. Although they were used only for instructional purposes, in 1828 Jedlik demonstrated the first device to contain the three components of practical DC motors, the stator, rotor and commutator. The device employed no permanent magnets, as the fields of both the stationary and revolving components were produced solely by the currents flowing through their windings. His motor set a record which was improved only four years later in September 1838 by Jacobi himself. His second motor was powerful enough to drive a boat with 14 people across a wide river and it was not until 1839/40 that other developers worldwide managed to build motors of similar and later also of higher performance. The first commutator DC electric motor capable of turning machinery was invented by the British scientist William Sturgeon in 1832, following Sturgeons work, a commutator-type direct-current electric motor made with the intention of commercial use was built by the American inventor Thomas Davenport, which he patented in 1837. The motors ran at up to 600 revolutions per minute, and powered machine tools, due to the high cost of primary battery power, the motors were commercially unsuccessful and Davenport went bankrupt. Several inventors followed Sturgeon in the development of DC motors but all encountered the same battery power cost issues, no electricity distribution had been developed at the time
13.
Internal combustion engine
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An internal combustion engine is a heat engine where the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine, the force is applied typically to pistons, turbine blades, rotor or a nozzle. This force moves the component over a distance, transforming chemical energy into mechanical energy. The first commercially successful internal combustion engine was created by Étienne Lenoir around 1859, firearms are also a form of internal combustion engine. Working fluids can be air, hot water, pressurized water or even liquid sodium, ICEs are usually powered by energy-dense fuels such as gasoline or diesel, liquids derived from fossil fuels. While there are many applications, most ICEs are used in mobile applications and are the dominant power supply for vehicles such as cars, aircraft. Typically an ICE is fed with fossil fuels like natural gas or petroleum products such as gasoline, there is a growing usage of renewable fuels like biodiesel for compression ignition engines and bioethanol or methanol for spark ignition engines. Hydrogen is sometimes used, and can be made from fossil fuels or renewable energy. Various scientists and engineers contributed to the development of internal combustion engines, in 1791, John Barber developed a turbine. In 1794 Thomas Mead patented a gas engine, also in 1794 Robert Street patented an internal combustion engine, which was also the first to use liquid fuel, and built an engine around that time. In 1798, John Stevens built the first American internal combustion engine, in 1807, Swiss engineer François Isaac de Rivaz built an internal combustion engine ignited by electric spark. In 1823, Samuel Brown patented the first internal combustion engine to be applied industrially, in 1860, Belgian Jean Joseph Etienne Lenoir produced a gas-fired internal combustion engine. In 1864, Nikolaus Otto patented the first atmospheric gas engine, in 1872, American George Brayton invented the first commercial liquid-fuelled internal combustion engine. In 1876, Nikolaus Otto, working with Gottlieb Daimler and Wilhelm Maybach, patented the compressed charge, in 1879, Karl Benz patented a reliable two-stroke gas engine. In 1892, Rudolf Diesel developed the first compressed charge, compression ignition engine, in 1926, Robert Goddard launched the first liquid-fueled rocket. In 1939, the Heinkel He 178 became the worlds first jet aircraft, at one time, the word engine meant any piece of machinery — a sense that persists in expressions such as siege engine. A motor is any machine that produces mechanical power, traditionally, electric motors are not referred to as Engines, however, combustion engines are often referred to as motors. In boating an internal combustion engine that is installed in the hull is referred to as an engine, reciprocating piston engines are by far the most common power source for land and water vehicles, including automobiles, motorcycles, ships and to a lesser extent, locomotives
14.
Pulley
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A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a taut cable, supporting shell is referred to as a block. A pulley may also be called a sheave or drum and may have a groove or grooves between two flanges around its circumference. The drive element of a system can be a rope, cable, belt. Hero of Alexandria identified the pulley as one of six simple machines used to lift weights, pulleys are assembled to form a block and tackle in order to provide mechanical advantage to apply large forces. Pulleys are also assembled as part of belt and chain drives in order to power from one rotating shaft to another. A set of pulleys assembled so that they rotate independently on the axle from a block. Two blocks with an attached to one of the blocks. A block and tackle is assembled so one block is attached to fixed mounting point, the ideal mechanical advantage of the block and tackle is equal to the number of parts of the rope that support the moving block. This system is included in the list of simple machines identified by Renaissance scientists, if the rope and pulley system does not dissipate or store energy, then its mechanical advantage is the number of parts of the rope that act on the load. This can be shown as follows, consider the set of pulleys that form the moving block and the parts of the rope that support this block. If there are p of these parts of the supporting the load W. This means the force on the rope is T=W/p. Thus, the block and tackle reduces the force by the factor p. The simplest theory of operation for a pulley system assumes that the pulleys and lines are weightless, and it is also assumed that the lines do not stretch. In equilibrium, the forces on the block must sum to zero. In addition the tension in the rope must be the same for each of its parts and this means that the two parts of the rope supporting the moving block must each support half the load. These are different types of systems, Fixed, A fixed pulley has an axle mounted in bearings attached to a supporting structure. A fixed pulley changes the direction of the force on a rope or belt that moves along its circumference, mechanical advantage is gained by combining a fixed pulley with a movable pulley or another fixed pulley of a different diameter
15.
Composite material
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The individual components remain separate and distinct within the finished structure. The new material may be preferred for reasons, common examples include materials which are stronger, lighter. More recently, researchers have begun to actively include sensing, actuation, computation and communication into composites. The most advanced examples perform routinely on spacecraft and aircraft in demanding environments, the earliest man-made composite materials were straw and mud combined to form bricks for building construction. Ancient brick-making was documented by Egyptian tomb paintings, wattle and daub is one of the oldest man-made composite materials, at over 6000 years old. Concrete is also a material, and is used more than any other man-made material in the world. As of 2006, about 7.5 billion cubic metres of concrete are made each year—more than one metre for every person on Earth. 2181–2055 BC and was used for death masks Cob Mud Bricks, concrete was described by Vitruvius, writing around 25 BC in his Ten Books on Architecture, distinguished types of aggregate appropriate for the preparation of lime mortars. For structural mortars, he recommended pozzolana, which were volcanic sands from the beds of Pozzuoli brownish-yellow-gray in colour near Naples. Natural cement-stones, after burning, produced cements used in concretes from post-Roman times into the 20th century, the glass fiber is relatively strong and stiff, whereas the polymer is ductile. Thus the resulting fiberglass is relatively stiff, strong, flexible, concrete is the most common artificial composite material of all and typically consists of loose stones held with a matrix of cement. Concrete is a material, and will not compress or shatter even under quite a large compressive force. However, concrete cannot survive tensile loading, therefore, to give concrete the ability to resist being stretched, steel bars, which can resist high stretching forces, are often added to concrete to form reinforced concrete. Fibre-reinforced polymers or FRPs include carbon-fiber-reinforced polymer or CFRP, and glass-reinforced plastic or GRP, if classified by matrix then there are thermoplastic composites, short fiber thermoplastics, long fibre thermoplastics or long fibre-reinforced thermoplastics. There are numerous thermoset composites, including paper composite panels, many advanced thermoset polymer matrix systems usually incorporate aramid fibre and carbon fibre in an epoxy resin matrix. Shape memory polymer composites are high-performance composites, formulated using fibre or fabric reinforcement and they can also be reheated and reshaped repeatedly without losing their material properties. These composites are ideal for such as lightweight, rigid, deployable structures, rapid manufacturing. Although high strain composites exhibit many similarities to shape memory polymers, Composites can also use metal fibres reinforcing other metals, as in metal matrix composites or ceramic matrix composites, which includes bone, cermet and concrete
16.
Hole saw
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A hole saw, also known as a hole cutter, is a saw blade of annular shape, whose annular kerf creates a hole in the workpiece without having to cut up the core material. Hole saws typically have a drill bit at their center to keep the saw teeth from walking. The fact that a hole saw creates the hole without needing to cut up the core often makes it preferable to twist drills or spade drills for relatively large holes, the same hole can be made faster and using less power. The depth to which a hole saw can cut is limited by the depth of its cup-like shape, most hole saws have a fairly short aspect ratio of diameter to depth, and they are used to cut through relatively thin workpieces. However, longer aspect ratios are available for applications that warrant them, the saw consists of a metal cylinder, usually steel, mounted on an arbor. The cutting edge either has saw teeth formed in it or industrial diamonds embedded in it, the arbor can carry a drill bit to bore a centering hole. After the first few millimeters of cut, the mechanism may no longer be needed. The sloping slots in the cylinder wall help carry the dust out, the kerf of the cut is designed to be slightly larger than the diameter of the rest of the hole saw so that it does not get jammed in the hole. Holes saws for use with portable drills are available in diameters from 6 to 130 mm. The only limit on the length of the cylinder, and thus depth of the hole, is the need to remove the bit from the hole to clear dust, a 300 mm cylinder length is not uncommon, although shorter bits are usual. By breaking the core off from time to time and using a shank extension, saw teeth are used for most materials, such as wood, plastic, soft plaster, and metal. Diamond hole saws are used to bore holes in brick, concrete, glass, an adjustable hole saw consists of a number of thin metal saw blade-like strips, and a flat disc with a large number of grooves in one side and a shank on the other. By snapping the blades into different grooves on the disc, a saw of a wide variety of sizes can be constructed. Another type of adjustable hole saw, also called a cutter, is formed by having one. To cut out a hole of any size, the teeth need only be adjusted to the proper position and this type is available in sizes up to a foot and larger, and can be used to accurately cut large circles. Another advantage over drill bits is the wider size capability, the core plug often binds inside the hole saw, and often must be pried out after each hole is cut. Sometimes the prying is quite difficult, sometimes the core plug will twist apart mid-cut, creating a condition where the core inside the hole saw spins on the yet-uncut portion of the core still in the workpiece. This tends to stop the action of the saw, and if the workpiece is wood or plastic
17.
Metal spinning
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Spinning can be performed by hand or by a CNC lathe. Metal spinning does not involve removal of material, as in conventional wood or metal turning, Metal spinning ranges from an artisans specialty to the most advantageous way to form round metal parts for commercial applications. Artisans use the process to produce architectural detail, specialty lighting, decorative household goods, commercial applications include rocket nose cones, cookware, gas cylinders, brass instrument bells, and public waste receptacles. Virtually any ductile metal may be formed, from aluminum or stainless steel, to high-strength, high-temperature alloys including INX, Inconel, Grade 50 / Corten, the diameter and depth of formed parts are limited only by the size of the equipment available. The spinning process is fairly simple, a formed block is mounted in the drive section of a lathe. A pre-sized metal disk is then clamped against the block by a pressure pad, the block and workpiece are then rotated together at high speeds. A localized force is applied to the workpiece to cause it to flow over the block. The force is applied via various levered tools. Simple workpieces are just removed from the block, but more complex shapes may require a multi-piece block, extremely complex shapes can be spun over ice forms, which then melt away after spinning. Because the final diameter of the workpiece is always less than the starting diameter, a more involved process, known as reducing or necking, allows a spun workpiece to include reentrant geometries. If surface finish and form are not critical, then the workpiece is spun on air, if the finish or form are critical then an eccentrically mounted mandrel is used. Hot spinning involves spinning a piece of metal on a lathe while high heat from a torch is applied to the workpiece, once heated, the metal is then shaped as the tool on the lathe presses against the heated surface forcing it to distort as it spins. Parts can then be shaped or necked down to a diameter with little force exerted. The basic hand metal spinning tool is called a spoon, though other tools can be used to effect varied results. Spinning tools can be made of hardened steel for using with aluminum or solid brass for spinning stainless steel or mild steel, some metal spinning tools are allowed to spin on bearings during the forming process. This reduces friction and heating of the tool, extending tool life, rotating tools may also be coated with thin film of ceramic to prolong tool life. Rotating tools are used during CNC metal spinning operations. Commercially, rollers mounted on the end of levers are used to form the material down to the mandrel in both hand spinning and CNC metal spinning
18.
Bearing (mechanical)
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A bearing is a machine element that constrains relative motion to only the desired motion, and reduces friction between moving parts. Most bearings facilitate the desired motion by minimizing friction, Bearings are classified broadly according to the type of operation, the motions allowed, or to the directions of the loads applied to the parts. Rotary bearings hold rotating components such as shafts or axles within mechanical systems, the simplest form of bearing, the plain bearing, consists of a shaft rotating in a hole. Lubrication is often used to reduce friction, a wide variety of bearing designs exists to allow the demands of the application to be correctly met for maximum efficiency, reliability, durability and performance. The term bearing is derived from the verb to bear, a bearing being an element that allows one part to bear another. The simplest bearings are bearing surfaces, cut or formed into a part, with varying degrees of control over the form, size, roughness, other bearings are separate devices installed into a machine or machine part. The most sophisticated bearings for the most demanding applications are very precise devices, the invention of the rolling bearing, in the form of wooden rollers supporting, or bearing, an object being moved is of great antiquity, and may predate the invention of the wheel. Though it is claimed that the Egyptians used roller bearings in the form of tree trunks under sleds. They are depicted in their own drawings in the tomb of Djehutihotep as moving massive stone blocks on sledges with liquid-lubricated runners which would constitute a plain bearing, there are also Egyptian drawings of bearings used with hand drills. The earliest recovered example of a rolling element bearing is a ball bearing supporting a rotating table from the remains of the Roman Nemi ships in Lake Nemi. The wrecks were dated to 40 BC, leonardo da Vinci incorporated drawings of ball bearings in his design for a helicopter around the year 1500. This is the first recorded use of bearings in an aerospace design, however, Agostino Ramelli is the first to have published sketches of roller and thrust bearings. An issue with ball and roller bearings is that the balls or rollers rub against each other causing additional friction which can be reduced by enclosing the balls or rollers within a cage, the captured, or caged, ball bearing was originally described by Galileo in the 17th century. The first practical caged-roller bearing was invented in the mid-1740s by horologist John Harrison for his H3 marine timekeeper and this uses the bearing for a very limited oscillating motion but Harrison also used a similar bearing in a truly rotary application in a contemporaneous regulator clock. The first modern recorded patent on ball bearings was awarded to Philip Vaughan and his was the first modern ball-bearing design, with the ball running along a groove in the axle assembly. Bearings played a role in the nascent Industrial Revolution, allowing the new industrial machinery to operate efficiently. For example, they saw use for holding wheel and axle to greatly reduce friction over that of dragging an object by making the act over a shorter distance as the wheel turned. The first plain and rolling-element bearings were wood closely followed by bronze, over their history bearings have been made of many materials including ceramic, sapphire, glass, steel, bronze, other metals and plastic which are all used today
19.
Screw thread
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A screw thread, often shortened to thread, is a helical structure used to convert between rotational and linear movement or force. A screw thread is a ridge wrapped around a cylinder or cone in the form of a helix, with the former being called a straight thread, a screw thread is the essential feature of the screw as a simple machine and also as a fastener. The mechanical advantage of a screw depends on its lead. This characteristic is essential to the vast majority of its uses, the tightening of a fasteners screw thread is comparable to driving a wedge into a gap until it sticks fast through friction and slight elastic deformation. Screw threads have several applications, Fastening, Fasteners such as screws, machine screws, nuts. Connecting threaded pipes and hoses to each other and to caps, gear reduction via worm drives Moving objects linearly by converting rotary motion to linear motion, as in the leadscrew of a jack. Measuring by correlating linear motion to rotary motion, as in a micrometer, both moving objects linearly and simultaneously measuring the movement, combining the two aforementioned functions, as in a leadscrew of a lathe. In all of these applications, the thread has two main functions, It converts rotary motion into linear motion. It prevents linear motion without the corresponding rotation, every matched pair of threads, external and internal, can be described as male and female. For example, a screw has male threads, while its matching hole has female threads, the helix of a thread can twist in two possible directions, which is known as handedness. This is known as a thread, because it follows the right hand grip rule. Threads oriented in the direction are known as left-handed. By common convention, right-handedness is the default handedness for screw threads, therefore, most threaded parts and fasteners have right-handed threads. Left-handed thread applications include, Where the rotation of a shaft would cause a conventional right-handed nut to loosen rather than to tighten due to fretting induced precession, examples include, The left hand pedal on a bicycle. The left-hand grinding wheel on a bench grinder, the lug nuts on the left side of some automobiles. The securing nut on some circular saw blades - the large torque at startup should tend to tighten the nut. The spindle on brushcutter and line trimmer heads, so that the torque tends to tighten rather than loosen the connection In combination with right-hand threads in turnbuckles, in such a case, the coupling will have one right-handed and one left-handed thread. In some instances, for example early ballpoint pens, to provide a method of disassembly
20.
Leadscrew
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A leadscrew, also known as a power screw or translation screw, is a screw used as a linkage in a machine, to translate turning motion into linear motion. Because of the area of sliding contact between their male and female members, screw threads have larger frictional energy losses compared to other linkages. They are not typically used to high power, but more for intermittent use in low power actuator. Common applications are linear actuators, machine slides, vises, presses, leadscrews are manufactured in the same way as other thread forms. A lead screw is used with a split nut also called half nut which allows the nut to be disengaged from the threads and moved axially, independently of the screws rotation. Power screws are classified by the geometry of their thread, V-threads are less suitable for leadscrews than others such as ACME because they have more friction between the threads. Their threads are designed to induce this friction to keep the fastener from loosening, leadscrews, on the other hand, are designed to minimize friction. Therefore, in most commercial and industrial use, V-threads are avoided for leadscrew use, nevertheless, V-threads are sometimes successfully used as leadscrews, for example on microlathes and micromills. Square threads are named after their square geometry and they are the most efficient, having the least friction, so they are often used for screws that carry high power. But they are also the most difficult to machine, and are thus the most expensive, acme threads have a 29° thread angle, which is easier to machine than square threads. They are not as efficient as square threads, due to the increased friction induced by the thread angle, ACME Threads are generally also stronger than square threads due to their trapezoidal thread profile, which provides greater load-bearing capabilities. Buttress threads are of a triangular shape and these are used where the load force on the screw is only applied in one direction. They are as efficient as square threads in these applications, but are easier to manufacture, due to the low efficiency they cannot be used in continuous power transmission applications. They also have a degree of friction on the threads. For square threads, the nut must be replaced, for trapezoidal threads and this is most easily described for a square or buttress thread as the thread angle is 0 and has no bearing on the calculations. The unwrapped thread forms a right triangle where the base is π d m long. An equivalent comparison is when the angle is greater than the lead angle. When this is not true the screw will back-drive, or lower under the weight of the load, if the leadscrew has a collar in which the load rides on then the frictional forces between the interface must be accounted for in the torque calculations as well
21.
Gear
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A gear or cogwheel is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part to transmit torque. Geared devices can change the speed, torque, and direction of a power source, Gears almost always produce a change in torque, creating a mechanical advantage, through their gear ratio, and thus may be considered a simple machine. The teeth on the two meshing gears all have the same shape, two or more meshing gears, working in a sequence, are called a gear train or a transmission. A gear can mesh with a linear toothed part, called a rack, the gears in a transmission are analogous to the wheels in a crossed, belt pulley system. An advantage of gears is that the teeth of a gear prevent slippage, in transmissions with multiple gear ratios—such as bicycles, motorcycles, and cars—the term gear as in first gear refers to a gear ratio rather than an actual physical gear. The term describes similar devices, even when the ratio is continuous rather than discrete, or when the device does not actually contain gears. Early examples of gears date from the 4th century BC in China, examples of further development include, Ma Jun used gears as part of a south-pointing chariot. The Antikythera mechanism is an example of an early and intricate geared device. Its time of construction is now estimated between 150 and 100 BC, the water-powered grain-mill, the water-powered saw mill, fulling mill, and other applications of watermill often used gears. The first mechanical clocks were built in AD725, the 1386 Salisbury cathedral clock may be the worlds oldest working mechanical clock. The definite ratio that teeth give gears provides an advantage over other drives in precision machines such as watches that depend upon an exact velocity ratio, an external gear is one with the teeth formed on the outer surface of a cylinder or cone. Conversely, a gear is one with the teeth formed on the inner surface of a cylinder or cone. For bevel gears, a gear is one with the pitch angle exceeding 90 degrees. Internal gears do not cause output shaft direction reversal, spur gears or straight-cut gears are the simplest type of gear. They consist of a cylinder or disk with teeth projecting radially, though the teeth are not straight-sided, the edge of each tooth is straight and aligned parallel to the axis of rotation. These gears mesh together correctly only if fitted to parallel shafts, No axial thrust is created by the tooth loads. Spur gears are excellent at moderate speeds but tend to be noisy at high speeds, helical or dry fixed gears offer a refinement over spur gears. The leading edges of the teeth are not parallel to the axis of rotation, since the gear is curved, this angling makes the tooth shape a segment of a helix
22.
Metalworking
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Metalworking is the process of working with metals to create individual parts, assemblies, or large-scale structures. The term covers a range of work from large ships and bridges to precise engine parts. It therefore includes a wide range of skills, processes. Metalworking is a science, art, hobby, industry and trade and its historical roots span cultures, civilizations, and millennia. Metalworking has evolved from the discovery of smelting various ores, producing malleable and ductile metal useful for tools, modern metalworking processes, though diverse and specialized, can be categorized as forming, cutting, or joining processes. Todays machine shop includes a number of machine tools capable of creating a precise, the oldest archaeological evidence of copper mining and working was the discovery of a copper pendant in northern Iraq from 8,700 BCE. The earliest substantiated and dated evidence of metalworking in the Americas was the processing of copper in Wisconsin, Copper was hammered until brittle then heated so it could be worked some more. This technology is dated to about 4000-5000 BCE, the oldest gold artifacts in the world come from the Bulgarian Varna Necropolis and date from 4450 BCE. Not all metal required fire to obtain it or work it, isaac Asimov speculated that gold was the first metal. His reasoning is that by its chemistry it is found in nature as nuggets of pure gold, in other words, gold, as rare as it is, is sometimes found in nature as the metal that it is. There are a few metals that sometimes occur natively. Almost all other metals are found in ores, a mineral-bearing rock, another feature of gold is that it is workable as it is found, meaning that no technology beyond a stone hammer and anvil to work the metal is needed. This is a result of properties of malleability and ductility. The earliest tools were stone, bone, wood, and sinew, at some unknown point the connection between heat and the liberation of metals from rock became clear, rocks rich in copper, tin, and lead came into demand. These ores were mined wherever they were recognized, remnants of such ancient mines have been found all over Southwestern Asia. Metalworking was being carried out by the South Asian inhabitants of Mehrgarh between 7000–3300 BCE, the end of the beginning of metalworking occurs sometime around 6000 BCE when copper smelting became common in Southwestern Asia. Ancient civilisations knew of seven metals. Here they are arranged in order of their potential, Iron +0.44 V
23.
Computer-aided design
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Computer-aided design is the use of computer systems to aid in the creation, modification, analysis, or optimization of a design. CAD software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, CAD output is often in the form of electronic files for print, machining, or other manufacturing operations. The term CADD is also used and its use in designing electronic systems is known as electronic design automation, or EDA. In mechanical design it is known as mechanical design automation or computer-aided drafting, however, it involves more than just shapes. CAD may be used to design curves and figures in space, or curves, surfaces. CAD is also used to produce computer animation for special effects in movies, advertising and technical manuals. The modern ubiquity and power of computers means that even perfume bottles, because of its enormous economic importance, CAD has been a major driving force for research in computational geometry, computer graphics, and discrete differential geometry. The design of models for object shapes, in particular, is occasionally called computer-aided geometric design. Eventually CAD provided the designer with the ability to perform engineering calculations, during this transition, calculations were still performed either by hand or by those individuals who could run computer programs. CAD was a change in the engineering industry, where draftsmen, designers. It did not eliminate departments, as much as it merged departments and empowered draftsman, CAD is just another example of the pervasive effect computers were beginning to have on industry. Current computer-aided design software packages range from 2D vector-based drafting systems to 3D solid, modern CAD packages can also frequently allow rotations in three dimensions, allowing viewing of a designed object from any desired angle, even from the inside looking out. Some CAD software is capable of mathematical modeling, in which case it may be marketed as CAD. CAD technology is used in the design of tools and machinery and in the drafting and design of all types of buildings and it can also be used to design objects. Furthermore, many CAD applications now offer advanced rendering and animation capabilities so engineers can better visualize their product designs, 4D BIM is a type of virtual construction engineering simulation incorporating time or schedule related information for project management. CAD has become an important technology within the scope of computer-aided technologies, with benefits such as lower product development costs. CAD enables designers to layout and develop work on screen, print it out, computer-aided design is one of the many tools used by engineers and designers and is used in many ways depending on the profession of the user and the type of software in question. Document management and revision control using Product Data Management, potential blockage of view corridors and shadow studies are also frequently analyzed through the use of CAD
24.
Computer-aided manufacturing
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Computer-aided manufacturing is the use of software to control machine tools and related ones in the manufacturing of workpieces. CAM is now a used in schools and lower educational purposes. CAM is used in schools alongside computer-aided design to create objects. Historically, CAM software was seen to have shortcomings that necessitated an overly high level of involvement by skilled CNC machinists. Fallows created the first CAD software but this had severe shortcomings and was taken back into the developing stage. CAM software would output code for the least capable machine, as machine tool control added on to the standard G-code set for increased flexibility. In some cases, such as set up CAM software or specific tools. None of these issues were so insurmountable that an engineer or skilled machine operator could not overcome for prototyping or small production runs. In high production or high precision shops, a different set of problems were encountered where an experienced CNC machinist must both hand-code programs and run CAM software, integration of CAD with other components of CAD/CAM/CAE Product lifecycle management environment requires an effective CAD data exchange. CAM packages could not, and still cannot, reason as a machinist can and they could not optimize toolpaths to the extent required of mass production. Users would select the type of tool, machining process and paths to be used, while an engineer may have a working knowledge of G-code programming, small optimization and wear issues compound over time. Mass-produced items that require machining are often created through casting or some other non-machine method. This enables hand-written, short, and highly optimized G-code that could not be produced in a CAM package. At least in the United States, there is a shortage of young, skilled machinists entering the workforce able to perform at the extremes of manufacturing, high precision and mass production. User confidence is built on 3D visualization through a closer integration with the 3D CAD environment. Manufacturing complexity The manufacturing environment is increasingly complex, the need for CAM and PLM tools by buMs are NC programmer or machinist is similar to the need for computer assistance by the pilot of modern aircraft systems. The modern machinery cannot be used without this assistance. Todays CAM systems support the range of machine tools including, turning,5 axis machining
25.
Numerical control
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Computer numerical control is the automation of machine tools by means of computers executing pre-programmed sequences of machine control commands. This is in contrast to machines that are controlled by hand wheels or levers. In modern CNC systems, the design of a mechanical part, the parts mechanical dimensions are defined using computer-aided design software, and then translated into manufacturing directives by computer-aided manufacturing software. The resulting directives are transformed into the specific commands necessary for a machine to produce the component. Since any particular component might require the use of a number of different tools – drills, saws, in other installations, a number of different machines are used with an external controller and human or robotic operators that move the component from machine to machine. In either case, the series of steps needed to produce any part is highly automated and produces a part that closely matches the original CAD design. The first NC machines were built in the 1940s and 1950s and these early servomechanisms were rapidly augmented with analog and digital computers, creating the modern CNC machine tools that have revolutionized the machining processes. Motion is controlled along multiple axes, normally at least two, and a spindle that moves in the Z. The position of the tool is driven by direct-drive stepper motor or servo motors in order to provide highly accurate movements, or in older designs, open-loop control works as long as the forces are kept small enough and speeds are not too great. On commercial metalworking machines, closed loop controls are standard and required in order to provide the accuracy, speed, as the controller hardware evolved, the mills themselves also evolved. Most new CNC systems built today are 100% electronically controlled, cNC-like systems are now used for any process that can be described as a series of movements and operations. CNC mills use computer controls to cut different materials and they are able to translate programs consisting of specific numbers and letters to move the spindle to various locations and depths. Many use G-code, which is a programming language that many CNC machines understand. These proprietary languages, while often simpler than G-code, are not transferable to other machines, CNC mills have many functions including face milling, shoulder milling, tapping, drilling and some even offer turning. Standard linear CNC mills are limited to 3 axis, but others may also have one or more rotational axes, today, CNC mills can have 4 to 6 axes. Lathes are machines that cut workpieces while they are rotated, CNC lathes are able to make fast, precision cuts, generally using indexable tools and drills. They are particularly effective for complicated programs designed to make parts that would be infeasible to make on manual lathes, CNC lathes have similar control specifications to CNC mills and can often read G-code as well as the manufacturers proprietary programming language. CNC lathes generally have two axes, but newer models have more axes, allowing for more advanced jobs to be machined, plasma cutting involves cutting a material using a plasma torch
26.
Stewart platform
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Devices placed on the top plate can be moved in the six degrees of freedom in which it is possible for a freely-suspended body to move. These are the three linear movements x, y, z, and the three rotations pitch, roll, & yaw, the terms six-axis or 6-DoF platform are also used, also synergistic. Although the short title Stewart Platform is now used for this jack layout, to be more precise, the original Stewart platform had a slightly different design. See the more detailed references at the end of this article, because the device has six jacks, it is often also known as a hexapod. The trademarked name hexapod was originally for Stewart platforms used in machine tools, however, the term is now used for 6-jack platforms outside of the machine tool area, since it simply means six legs. The Stewart platform design is used in flight simulation, particularly in the so-called full flight simulator for which all 6 degrees of freedom are required. In this role, the payload is a replica cockpit and a display system, normally of several channels. Payload weights in the case of a flight simulator for a large transport aircraft can be up to about 15,000 kilogrammes. Similar platforms are used in driving simulators, typically mounted on large x-y tables to simulate short term acceleration, long term acceleration can be simulated by tilting the platform, and an active research area is how to mix the two. James S. Albus of the National Institute of Standards and Technology developed the RoboCrane, the Low impact docking system developed by NASA uses a Stewart platform to manipulate space vehicles during the docking process. The Computer Assisted Rehabilitation Environment developed by Motek Medical uses a Stewart platform coupled with virtual reality to do advanced biomechanical and clinical research, dr. J. Eric Gough was an automotive engineer and worked at Fort Dunlop, the Dunlop Tyres factory in Birmingham, England. He developed his Universal Tyre-Testing Machine in the 1950s and his platform was operational by 1954, the rig was able to mechanically test tyres under combined loads. Dr. Gough died in 1972 but his testing rig continued to be used up until the late 1980s when the factory was closed down and his rig was saved and transported to the Science Museum storage facility at Wroughton near Swindon. Parallel manipulator Robot kinematics Acceleration onset cueing Linear actuator Bonev, I. A, the True Origins of Parallel Robots, ParalleMIC online review Pictures of the NIST/Ingersoll prototype octahedral hexapod Hexapod Structures for Surgery Hexapod for Astronomy
27.
Die head
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A die head is a threading die that is used in the high volume production of threaded components. Die heads are used on lathes, turret lathes, screw machines. They may be used for cutting a thread or rolling a thread. They may also be used for internal or external thread cutting, in operation, there are usually four moveable chasers that cut the thread then back away from the work to permit rapid removal of the tool. The lower picture at the shows four sets of chasers. Each set of chasers is designed to cut a different thread, one set of chasers would be used at a time, each chaser is inserted into the die head and the die head is closed bringing the chasers down to their cutting position. When sufficient length of thread has been cut the die head will open allowing for rapid retraction of the head without interference with the newly formed thread, the die head shown cuts an outside thread. There are also collapsible die heads that are used to cut an internal thread, the bottom picture shows a Die Head used for Thread Rolling. A Rolled Thread may have greater strength than a cut thread, hartness Flat Turret Lathe Manual, A Hand Book for Operators. Springfield, Vermont and London, Jones & Lamson Machine Company
28.
Drill bit
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Drill bits are cutting tools used to remove material to create holes, almost always of circular cross-section. Drill bits come in sizes and shape and can create different kinds of holes in many different materials. In order to create holes drill bits are attached to a drill, the drill will grasp the upper end of a bit called the shank in the chuck. Drill bits come in sizes, described in the drill bit sizes article. A comprehensive drill bit and tap size chart lists metric and imperial sized drill bits alongside the required screw tap sizes, there are also certain specialized drill bits that can create holes with a non-circular cross-section. While the term drill may refer to either a machine or a drill bit for use in a drilling machine. In this article, for clarity, drill bit or bit is used throughout to refer to a bit for use in a drilling machine, Drill bit geometry has several characteristics, The spiral in the drill bit controls the rate of chip removal. A fast spiral drill bit is used in high feed rate applications under low spindle speeds, the point angle, or the angle formed at the tip of the bit, is determined by the material the bit will be operating in. Harder materials require a larger point angle, and softer materials require a sharper angle, the correct point angle for the hardness of the material influences wandering, chatter, hole shape, and wear rate. The lip angle determines the amount of support provided to the cutting edge, a greater lip angle will cause the bit to cut more aggressively under the same amount of point pressure as a bit with a smaller lip angle. Both conditions can cause binding, wear, and eventual failure of the tool. The proper amount of lip clearance is determined by the point angle, the length of a bit determines how deep a hole can be drilled, and also determines the stiffness of the bit and accuracy of the resultant hole. While longer bits can drill deeper holes, they are flexible meaning that the holes they drill may have an inaccurate location or wander from the intended axis. Twist drill bits are available in lengths, referred to as Stub-length or Screw-Machine-length, the extremely common Jobber-length. Most drill bits for use have straight shanks. For heavy duty drilling in industry, bits with tapered shanks are sometimes used, other types shanks used include hex-shaped, and various proprietary quick release systems. The diameter-to-length ratio of the bit is usually between 1,1 and 1,10. Much higher ratios are possible, but the higher the ratio, the best geometry to use depends upon the properties of the material being drilled
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Drill bit shank
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The shank is the end of a drill bit grasped by the chuck of a drill. The cutting edges of the drill bit contact the workpiece, and are connected via the shaft with the shank, in many cases a general-purpose arrangement is used, such as a bit with cylindrical shaft and shank in a three-jaw chuck which grips a cylindrical shank tightly. Different shank and chuck combination can deliver improved performance, such as allowing higher torque, greater centering accuracy, or moving the bit and this shank was common before 1850, and is still in production. At first, the shank was just rammed into a square hole in the end of the drill. Over time, various designs have been invented, and modern chucks can grasp. It has been difficult to find a reference to the angle of the taper, but 7 different bits were measured. The whole of the bit, shaft and shank, is usually of the same diameter. It is held usually in a 3-jaw drill chuck, bits of diameter too small to grip firmly can have straight shanks of larger diameter than the drill, which can be held firmly in a standard size collet or chuck. Large drill bits can have straight shanks narrower than the drill diameter so that they can be fitted in chucks not able to chuck the full diameter, such a drill bit is called a reduced-shank or blacksmiths drill. For example, this allows a 1/2 bit to be used in a pistol-grip drills 3/8 chuck, one particular type of reduced-shank drill bits are Silver & Deming bits, whose sets run from 9/16 to 1-1/2 drill body diameter with a standard 1/2 reduced shank for all. This allows drill presses with 1/2 chucks to run the larger drills, s&D bits are 6 long with a 3 flute length. A hex shank can be grasped by a 3-jaw drill chuck or held in a specifically for hex shanks. Quarter-inch hex shanks are common for machine screwdriver bits and have spread from that application to be used for drill bits that are compatible with screwdriver machinery. The SDS shank has the advantage of fitting into a simple spring-loaded chuck and this shank and chucks made for it are especially suited to hammer drilling with masonry drills in stone and concrete. The drill bit is not held solidly in the chuck, but can slide back and forth like a piston, it not slip during rotation due to the non-circular shank cross-section. Rotational drive uses the sliding keyways that open to the end of the shank, the smaller indentations that do not open to the end are grasped by the chuck to prevent the drill bit falling out. The hammer of the hits the flat end of the shank. The shank must be lubricated with grease to allow it to slide in the chuck, there are three standard sizes of SDS, SDS-plus, SDS-Top and SDS-max
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Drill bit sizes
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Drill bits are the cutting tools of drilling machines. They can be made in any size to order, but standards organizations have defined sets of sizes that are produced routinely by drill bit manufacturers, in the U. S. fractional inch and gauge drill bit sizes are in common use. In nearly all countries, metric drill bit sizes are most common. The British Standards on replacing gauge size drill bits with metric sizes in the UK was first published in 1959, a comprehensive table for metric, fractional wire and tapping sizes can be found at the drill and tap size chart. Metric drill bit sizes define the diameter of the bit in terms of standard metric lengths, Standards organizations define sets of sizes that are conventionally manufactured and stocked. For example, British Standard BS328 defines sizes from 0.2 mm to 25.0 mm. This reflects both the smaller drilled hole diameter tolerance possible on smaller holes and the wishes of designers to have drill bit sizes available within at most 10% of an arbitrary hole size, the price and availability of particular size bits does not change uniformly across the size range. Bits at size increments of 1 mm are most commonly available, sets of bits in 1 mm increments might be found on a market stall. In 0.5 mm increments, any hardware store, in 0.1 mm increments, any engineers store. Sets are not commonly available in smaller size increments, except for drill bits below 1 mm diameter, drill bits of the less routinely used sizes, such as 2.55 mm, would have to be ordered from a specialist drill bit supplier. This subsetting of standard sizes is in contrast to practice with number gauge drill bits. Metric dimensioning is routinely used for drill bits of all types, for example, a set of Forstner bits may contain 10,15,20,25 and 30 mm diameter cutters. ANSI B94. 11M-1979 sets size standards for jobber-length straight-shank twist drill bits from 1/64 inch through 1 inch in 1/64 inch increments, drill bit sizes are written down on paper and etched onto bits as irreducible fractions. So, instead of 78/64 inch, or 1 14/64 inch, below is a chart providing the decimal-fraction equivalents that are most relevant to fractional-inch drill bit sizes. Fractional inch drill bit sizes are still in use in the US. In the past, they were elsewhere, but they have now been largely discarded in favour of metric sizes. Number drill bit gauge sizes range from size 80 to size 1 followed by letter gauge size A to size Z. Although the ASME B94. 11M twist drill standard, for example, lists sizes as small as size 97, sizes smaller than 80 are rarely encountered in practice
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Drilling
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Drilling is a cutting process that uses a drill bit to cut a hole of circular cross-section in solid materials. The drill bit is usually a rotary cutting tool, often multipoint, the bit is pressed against the workpiece and rotated at rates from hundreds to thousands of revolutions per minute. This forces the cutting edge against the workpiece, cutting off chips from the hole as it is drilled, in rock drilling, the hole is usually not made through a circular cutting motion, though the bit is usually rotated. Instead, the hole is made by hammering a drill bit into the hole with quickly repeated short movements. The hammering action can be performed from outside of the hole or within the hole, drills used for horizontal drilling are called drifter drills. In rare cases, specially-shaped bits are used to cut holes of non-circular cross-section, drilled holes are characterized by their sharp edge on the entrance side and the presence of burrs on the exit side. Also, the inside of the hole usually has helical feed marks and this causes the workpiece to become more susceptible to corrosion and crack propagation at the stressed surface. A finish operation may be done to avoid these detrimental conditions, for fluted drill bits, any chips are removed via the flutes. Chips may form long spirals or small flakes, depending on the material, the type of chips formed can be an indicator of the machinability of the material, with long chips suggesting poor material machinability. When possible drilled holes should be located perpendicular to the workpiece surface and this minimizes the drill bits tendency to walk, that is, to be deflected from the intended center-line of the bore, causing the hole to be misplaced. The higher the ratio of the drill bit, the greater the tendency to walk. Constraining the position of the drill bit using a jig with drill bushings Surface finish produced by drilling may range from 32 to 500 microinches. Finish cuts will generate surfaces near 32 microinches, and roughing will be near 500 microinches, cutting fluid is commonly used to cool the drill bit, increase tool life, increase speeds and feeds, increase the surface finish, and aid in ejecting chips. Application of these fluids is usually done by flooding the workpiece with coolant and lubricant or by applying a spray mist, in deciding which drill to use it is important to consider the task at hand and evaluate which drill would best accomplish the task. There are a variety of styles that each serve a different purpose. The subland drill is capable of drilling more than one diameter, the spade drill is used to drill larger hole sizes. The indexable drill is useful in managing chips, the purpose of spot drilling is to drill a hole that will act as a guide for drilling the final hole. The hole is only drilled part way into the workpiece because it is used to guide the beginning of the next drilling process
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Tap and die
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Taps and dies are tools used to create screw threads, which is called threading. Many are cutting tools, others are forming tools, a tap is used to cut or form the female portion of the mating pair. A die is used to cut or form the male portion of the mating pair, the process of cutting or forming threads using a tap is called tapping, whereas the process using a die is called threading. Both tools can be used to clean up a thread, which is called chasing, however, using an ordinary tap or die to clean threads will generally result in the removal of some material, which will result in looser and weaker threads. Because of this, threads are typically cleaned using special taps and dies made for this purpose, chasers are made of softer materials and are not capable of cutting new threads, however they are still tighter fitting than actual fasteners and are fluted like regular taps and dies. One particularly common use is for automotive spark plug threads, which suffer from corrosion. As the loads grew ever heavier, bigger and stronger bolts were needed to resist breakage, some nuts and bolts were measured by the foot or yard. This development eventually led to a replacement of wood parts with metal parts of an identical measure. When a wooden part broke, it snapped, ripped. Metalworking taps and dies were made by their users during the 18th and 19th centuries, using such tools as lathes and files for the shaping. Thus builders of, for example, locomotives, firearms, or textile machinery were likely to make their own taps, during the 19th century the machining industries evolved greatly, and the practice of buying taps and dies from suppliers specializing in them gradually supplanted most such in-house work. Joseph Clement was one such early vendor of taps and dies, with the introduction of more advanced milling practice in the 1860s and 1870s, tasks such as cutting a taps flutes with a hand file became a thing of the past. In the early 20th century, thread-grinding practice went through significant evolution, further advancing the state of the art of cutting screw threads, including those of taps and dies. During the 19th and 20th centuries, thread standardization was evolving simultaneously with the techniques of thread generation, including taps, the largest tap and die company to exist in the United States was Greenfield Tap & Die of Greenfield, Massachusetts. GTD was so vital to the Allied war effort from 1940–1945 that anti-aircraft guns were placed around its campus in anticipation of possible Axis air attack. The GTD brand is now a part of Widia Products Group, a tap cuts a thread on the inside surface of a hole, creating a female surface which functions like a nut.5 threads of taper is typical. This feature enables a bottoming tap to cut threads to the bottom of a blind hole, in the US, they are commonly known as bottoming taps, but in Australia and Britain they are also known as plug taps. Intermediate tap, second tap, or plug tap The tap illustrated in the middle of the image has tapered cutting edges, the number of tapered threads typically ranges from 3 to 5
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Tap wrench
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A tap wrench is a hand tool used to turn taps or other small tools, such as hand reamers and screw extractors. There are two types of tap wrenches, double-end adjustable wrenches and T-handle wrenches. Double-end adjustable wrenches, also known as bar wrenches, have one threaded handle which is attached to one of the clamps, the clamp is opened to insert the tool and then tightened down against the tool to secure it. This type of tap wrench is used with larger taps and where there is room to turn a larger wrench and this type of wrench uses a collet to secure the tool. The collet design has two pieces, a threaded nosecap and four fingers, the collet fingers thread on the outside. The nosecap is tapered, which causes the fingers to clamp onto the tool and this style tap wrench is useful in confined spaces or where extra reach is required. The hole which forms the collet fingers may be sloped or may be stepped. Numerous sizes of tap wrenches are required to cover the size range of tool heads. Generally speaking, the smallest size which accommodates the tool head is recommended because it reduces the risk of breakage from excessive force
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Threading (manufacturing)
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Threading is the process of creating a screw thread. More screw threads are produced each year than any other machine element, there are many methods of generating threads, including subtractive methods, deformative or transformative methods, additive methods, or combinations thereof. There are various methods for generating screw threads, in general, certain thread-generating processes tend to fall along certain portions of the spectrum from toolroom-made parts to mass-produced parts, although there can be considerable overlap. Threads of metal fasteners are usually created on a rolling machine. They may also be cut with a lathe, tap or die, rolled threads are stronger than cut threads, with increases of 10% to 20% in tensile strength and possibly more in fatigue resistance and wear resistance. A common method of threading is cutting with taps and dies, unlike drill bits, hand taps do not automatically remove the chips they create. A hand tap cannot cut its threads in a single rotation because it creates long chips which quickly jam the tap and it may be necessary to periodically remove the tap from the hole to clear the chips, especially when a blind hole is threaded. For continuous tapping operations specialized spiral point or gun taps are used to eject the chips, single-point threading, also colloquially called single-pointing, is an operation that uses a single-point tool to produce a thread form on a cylinder or cone. The tool moves linearly while the rotation of the workpiece determines the lead of the thread. The process can be done to create external or internal threads, in external thread cutting, the piece can either be held in a chuck or mounted between two centers. With internal thread cutting, the piece is held in a chuck, the tool moves across the piece linearly, taking chips off the workpiece with each pass. Usually 5 to 7 light cuts create the depth of the thread. Today engine lathes and CNC lathes are the used machines for single-point threading. On CNC machines, the process is quick and easy due to the ability to constantly track the relationship of the tool position. CNC software includes canned cycles, that is, preprogrammed subroutines, parameters are entered, and the machine does the rest. Threads may be milled with a milling cutter if the correct helical toolpath can be arranged. This was formerly arranged mechanically, and it was suitable for mass-production work although uncommon in job-shop work, there are various types of thread milling, including several variants of form-milling and a combination of drilling and threading with one cutter, called thrilling. Form-milling uses either a single- or multiple-form cutter, in one variant of form-milling, the single-form cutter is tilted to the helix angle of the thread and then fed radially into the blank
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Abrasive
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An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away by friction. While finishing a material often means polishing it to gain a smooth, reflective surface, in short, the Ceramics which are used to cut, grind and polish other softer materials are known as Abrasives. Abrasives are extremely commonplace and are used extensively in a wide variety of industrial, domestic. This gives rise to a variation in the physical and chemical composition of abrasives as well as the shape of the abrasive. Common uses for abrasives include grinding, polishing, buffing, honing, cutting, drilling, sharpening, lapping, and sanding. Files are not abrasives, they remove material not by scratching or rubbing, however, diamond files are a form of coated abrasive. Abrasives generally rely upon a difference in hardness between the abrasive and the material being worked upon, the abrasive being the harder of the two substances. Diamond, an abrasive, for instance occurs both naturally and is industrially produced, as is corundum which occurs naturally but which is nowadays more commonly manufactured from bauxite. However, even softer minerals like calcium carbonate are used as abrasives and these minerals are either crushed or are already of a sufficiently small size to permit their use as an abrasive. These grains, commonly called grit, have rough edges, often terminating in points which will decrease the area in contact. The abrasive and the material to be worked are brought into contact while in motion to each other. Abrasives may be classified as natural or synthetic. When discussing sharpening stones, natural stones have long been considered superior, many synthetic abrasives are effectively identical to a natural mineral, differing only in that the synthetic mineral has been manufactured rather than been mined. Impurities in the mineral may make it less effective. Natural abrasives are often sold as dressed stones, usually in the form of a rectangular block, a bonded abrasive is composed of an abrasive material contained within a matrix, although very fine aluminium oxide abrasive may comprise sintered material. This matrix is called a binder and is often a clay, a resin and this mixture of binder and abrasive is typically shaped into blocks, sticks, or wheels. The most usual abrasive used is aluminium oxide, also common are silicon carbide, tungsten carbide and garnet. Artificial sharpening stones are often a bonded abrasive and are available as a two sided block, each side being a different grade of grit
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Angle grinder
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An angle grinder, also known as a side grinder or disc grinder, is a handheld power tool used for grinding and polishing. Angle grinders can be powered by a motor, petrol engine or compressed air. The motor drives a geared head at a right-angle on which is mounted an abrasive disc or a thinner cut-off disc, angle grinders typically have an adjustable guard and a side-handle for two-handed operation. Certain angle grinders, depending on their range, can be used as sanders. The backing system is made of hard plastic, phenolic resin. Angle grinders are standard equipment in metal fabrication shops and on construction sites and they are also common in machine shops, along with die grinders and bench grinders. Angle grinders may be used for removing material from a piece. The angle grinder has large bearings to counter side forces generated during cutting, unlike a power drill, angle grinders are widely used in metalworking and construction, as well as in emergency rescues. They are commonly found in workshops, service garages and auto repair shops. There is a variety of angle grinders to choose from when trying to find the right one for the job. The most important factors in choosing the right grinder are the disc size, other factors include power source, rpm, and arbor size. Generally disc size and power increase together, disc size is usually measured in inches or millimetres. Common disc sizes for angle grinders in the U. S. A. include 4,4.5,5,6,7,9 and 12 inches, discs for pneumatic grinders also come much smaller. Pneumatic grinders are used for lighter duty jobs where more precision is required. Electric grinders are commonly used for larger, heavy duty jobs. However, there are small electric grinders and large pneumatic grinders. Through a sound level and vibrations study conducted by the National Institute for Occupational Safety and Health. In addition, angle grinders produce sparks when cutting ferrous metals and they also produce shards cutting other materials
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Bench grinder
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A bench grinder is a benchtop type of grinding machine used to drive abrasive wheels. A pedestal grinder is a similar or larger version of grinder that is mounted on a pedestal and these types of grinders are commonly used to hand grind various cutting tools and perform other rough grinding. Depending on the bond and grade of the wheel, it may be used for sharpening cutting tools such as tool bits, drill bits, chisels. Alternatively, it may be used to shape metal prior to welding or fitting. A wire brush wheel or buffing wheels can be interchanged with the wheels in order to clean or polish workpieces. Stiff buffing wheels can also be used when deburring is the task at hand, some buffing machines are built on the same concept as bench grinders except for longer housings and arbors with buffing wheels instead of grinding wheels. Bench grinders are standard equipment in metal fabrication shops and machine shops, wheels come with maximum RPM ratings printed on the label. The grinders RPM must be equal or lower, the operating speeds indicated on the wheels tag must never be exceeded. Greatly overspeeding a grinding wheel makes it explode, which can injure or kill the operator like a gunshot would, the typical wheels on most bench grinders are vitreous-bond wheels. They work best to do their task, but they inherently have a risk of cracking. Grinding wheels designed for steel are not to be used for grinding softer metals, the soft metal gets lodged in the pores of the wheel and later expands with the heat of grinding. This can dislodge pieces of the wheel, causing injury. Grinding is prohibited on the side of a bench grinder wheel. Risk of wheel explosion otherwise threatens, some tool and cutter grinders have cup-shaped wheels designed to do grinding on the side. The tool rest needs to be tight and within 2 to 3 mm of the wheel and this prevents the workpiece from slipping down between the wheel and the tool rest. The spark arrestors catch stray sparks, grinding is usually done with the workpiece resting on the tool rest. This prevents sudden slips in which the wheel grabs the work momentarily, the wheel guards serve to intercept the fragments of an exploding wheel, keeping them from killing people or damaging surroundings. This is why running a grinder without the guards is prohibited, grinding metal on a power-driven grinding wheel quickly heats up the workpiece
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Coated abrasive
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A coated abrasive is an abrasive grain bonded to a flexible substrate using adhesives. Common substrates are paper, cloth, vulcanized fiber, and plastic films, the international standard for coated abrasives is ISO6344. Sandpaper and emery cloth are coated abrasives for hand use, usually non-precision and these two terms are used by general public in place of coated abrasives. Other coated abrasive forms include sanding cords, pads, belts, a quick change system is commonly used with disc type coated abrasives. A plastic or metal hub is bonded to one of the faces and this then mates directly to the sander/grinder or to a mandrel that can be mounted in a sander, grinder, or drill. The advantage is that the disc can be replaced when needed. Quick change discs range in sizes from 50 millimetres to no upper limit
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Cylindrical grinder
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The cylindrical grinder is a type of grinding machine used to shape the outside of an object. The cylindrical grinder can work on a variety of shapes, however the object must have an axis of rotation. This includes but is not limited to such shapes as a cylinder, an ellipse, while the majority of cylindrical grinders employ all four movements, there are grinders that only employ three of the four actions. The basis for the modern day cylindrical grinder was first built in the 1830s by two men working independently, Jonathan Bridges and James Wheaton. It is unclear as to which man had first produced the machine and it took another 40 years before further improvement and refinement of the tool occurred. The Brown & Sharpe company in Providence, RI was one of the first builders of the Willcox & Gibbs Sewing Machine, one of the first piece of machinery to be used in a residential setting. Joseph Brown believed that the shaft and needle bars of the machine must be crafted from hardened tool steel. It was this desire led to their experimentation with building a cylindrical grinder. The first attempt was simply a small lathe with a wheel mounted to it. Subsequent attempts led to the cylindrical grinder displayed at the 1876 Centennial Exposition and it is important to note that Brown & Sharpe cannot be given sole credit of pioneering advances in cylindrical grinding. A man in Waltham, Massachusetts, Ambrose Webster had created a small grinding machine in 1860 that contained all of the improvements Brown & Sharpe claimed to be their own original invention. Even more so, the emphasis on precision, accuracy, and he founded the Norton Grinding Company, where he continued improving the cylindrical grinder to use faster rpm values and more precise grinding tolerances. He was acknowledged for his work on April 18,1925 when he won The John Scott Medal and these standards developed by Norton were the status quo until about the middle of the 20th century. The remainder of technological innovation applicable to the grinder is almost identical and entangled in a sense. The innovation of the last 70 years can be characterized by three waves of change, the first wave was the creation of numerical control by John T. Parsons in the 1940s. The U. S. Air Force, looking for a faster, cheaper, the first implementation of NC in machine tools occurred in the 1950s and continued through the 1960s. The second wave of innovation, occurring during the 1970s and 1980s, is marked by the demand for microcomputers to be used to direct NC. The joining of computers marked the birth of Computer Numerical Control which once again revolutionized the ability of the cylindrical grinder, now the machine was able to receive instruction from a computer which would give it precise directions on every imaginable dimension and measurement needed to produce the desired product
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Diamond plate
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Diamond plate is usually steel, stainless steel or aluminum. Steel types are made by hot rolling, although modern manufacturers also make a raised and pressed diamond design. The added texture reduces the risk of slipping, making diamond plate a solution for stairs, catwalks, walkways and its non-skid properties mean that diamond plate is frequently used on the interior of ambulances and on the footplates of firetrucks. Additional applications include truck beds and trailer floors, diamond plate can also be used decoratively, particularly highly polished aluminum variants. Manufactured in plastic, diamond plate is marketed as a tile system to be installed on garage floors, trailers. Diamond plate may be used for protection against damage from foot traffic or other harmful chemicals. Manufactured with polymer variants, inter-locking diamond plate tile is used in areas with high surface-erosive traffic, tata Steel marketed the plate as Durbar Plate. Diamond plate can also refer to similar anti-slip textures
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Grinding (abrasive cutting)
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Grinding is an abrasive machining process that uses a grinding wheel as the cutting tool. It can produce very fine finishes and very accurate dimensions, yet in mass production contexts it can also rough out large volumes of metal quite rapidly. It is usually better suited to the machining of hard materials than is regular machining. Compared to regular machining, it is better suited to taking very shallow cuts. Grinding is a subset of cutting, as grinding is a true metal-cutting process, each grain of abrasive functions as a microscopic single-point cutting edge, and shears a tiny chip that is analogous to what would conventionally be called a cut chip. This is why the terms are used in separately in shop-floor practice. Lapping and sanding are subsets of grinding, selecting which of the following grinding operations to be used is determined by the size, shape, features and the desired production rate. Surface grinding uses an abrasive wheel to remove material, creating a flat surface. The tolerances that are achieved with grinding are ±2 × 10−4 inches for grinding a flat material. The surface grinder is composed of a wheel, a workholding device known as a chuck, either electromagnetic or vacuum. Grinding is commonly used on cast iron and various types of steel, materials that are less commonly ground are Aluminum, stainless steel, brass & plastics. These all tend to clog the cutting more than steel & cast iron. Cylindrical grinding is used to grind the cylindrical surfaces and shoulders of the workpiece, the workpiece is mounted on centers and rotated by a device known as a drive dog or center driver. The abrasive wheel and the workpiece are rotated by separate motors, the table can be adjusted to produce tapers. The wheel head can be swiveled, the five types of cylindrical grinding are, outside diameter grinding, inside diameter grinding, plunge grinding, creep feed grinding, and centerless grinding. A cylindrical grinder has a wheel, two centers that hold the workpiece, and a chuck, grinding dog, or other mechanism to drive the work. Most cylindrical grinding machines include a swivel to allow for the forming of tapered pieces, the wheel and workpiece move parallel to one another in both the radial and longitudinal directions. The abrasive wheel can have many shapes, standard disk-shaped wheels can be used to create a tapered or straight workpiece geometry while formed wheels are used to create a shaped workpiece
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Grinding dresser
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A grinding dresser or wheel dresser is a tool to dress the surface of a grinding wheel. Grinding dressers are used to return a wheel to its round shape, to expose fresh grains for renewed cutting action. The objective of dressing the wheel is to, True the wheel by knocking abrasive particles from the wheels surface and this minimizes vibration and improves surface finish, eliminating the vibration of the out-of-balance wheel across the workpieces surface. It is not unusual for grinding wheels to become out of round with use and this is partially from loaded areas of the wheel wearing at different rates from less loaded areas. It can also be exacerbated by grinding when the wheel is not under power, when bench grinders vibrate excessively, it is usually because the wheels have worn out of round and are thus out of balance. Truing them by dressing resolves this problem, dislodge these abrasive particles to expose fresh abrasive from the wheels surface. Each abrasive grain is a cutting tool, a worn grain has its edges dulled. Exposing the fresh grains is thus a sharpening process, glazing of the wheel is evidence of rounded grains and is noticeable by a reflective surface on the spinning wheel. If a workpiece is softer than the grade for which the wheel is designed, the wheel therefore appears to lose its edge especially as the pores between grains fill with fragments of the workpiece. The wheel is said to be loaded. This is one reason why the selection of wheel is extremely important, star dressers — A long handled tool with a row of free running, hardened and serrated, wavy discs or star-shaped cutters running at right angles to the handle. These are presented to the wheel as it is turned off. Diamond dressers — Shorter handled diamond tools that either have a matrix of small diamonds bonded to a surface on the end of the dresser or a single diamond mounted in their face. As the diamond is introduced to the face, the harder diamond remains attached. Dressing sticks — A stick of hard material, usually made from the same materials, norbide is one brand of dressing stick made by Norton Abrasives, from boron carbide. Also an abrasive wheel type that has a grinding wheel in a holder that is held against the spinning grinding wheel to dress. Four types of dressers are used to dress the wheels of CNC grinders used for grinding complex shapes, stationary dressers — a stationary dresser is a metal blade with a single diamond brazed into the tip. Crush rolls — a crush roll is a steel or tungsten carbide wheel
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Grinding machine
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A grinding machine, often shortened to grinder, is any of various power tools or machine tools used for grinding, which is a type of machining using an abrasive wheel as the cutting tool. Each grain of abrasive on the wheels surface cuts a small chip from the workpiece via shear deformation, grinding is used to finish workpieces that must show high surface quality and high accuracy of shape and dimension. As the accuracy in dimensions in grinding is of the order of 0.000025 mm, in most applications it tends to be an operation and removes comparatively little metal. However, there are some roughing applications in which grinding removes high volumes of metal quite rapidly, thus, grinding is a diverse field. The grinding machine consists of a bed with a fixture to guide and hold the piece. The speed is determined by the diameter and manufacturer’s rating. The grinding head can travel across a fixed work piece, or the piece can be moved while the grind head stays in a fixed position. Fine control of the head or table position is possible using a vernier calibrated hand wheel. Grinding machines remove material from the piece by abrasion, which can generate substantial amounts of heat. To cool the work piece so that it does not overheat and go outside its tolerance, the coolant also benefits the machinist as the heat generated may cause burns. These machines include the, Belt grinder, which is used as a machining method to process metals and other materials. Belt grinding is a versatile process suitable for all kind of applications, including finishing, deburring, bench grinder, which usually has two wheels of different grain sizes for roughing and finishing operations and is secured to a workbench or floor stand. Its uses include shaping tool bits or various tools that need to be made or repaired, cylindrical grinder, which includes both the types that use centers and the centerless types. A cylindrical grinder may have multiple grinding wheels, the workpiece is rotated and fed past the wheel to form a cylinder. It is used to make precision rods, tubes, bearing races, bushings, the most common surface grinders have a grinding wheel rotating on a horizontal axis cutting around the circumference of the grinding wheel. This type of machine removes large amounts of material and grinds flat surfaces with noted spiral grind marks and it can also be used to make and sharpen metal stamping die sets, flat shear blades, fixture bases or any flat and parallel surfaces. Surface grinders can be operated or have CNC controls. Tool and cutter grinder, which usually can perform the function of the drill bit grinder
