In electronics, rework is the repair or refinish of a printed circuit board (PCB) assembly, usually involving desoldering and re-soldering of surface-mounted electronic components (SMD). Mass processing techniques are not applicable to single device repair or replacement, and specialized manual techniques by expert personnel using appropriate equipment are required to replace defective components; area array packages such as ball grid array (BGA) devices particularly require expertise and appropriate tools. A hot air gun or hot air station is used to heat devices and melt solder, and specialised tools are used to pick up and position often tiny components.
A rework station is a place to do this workâthe tools and supplies for this work, typically on a workbench. Other kinds of rework require other tools.
Electronic assembly (PCBA)
X-ray picture of inadequate solder joints
Thermal profile of a lead free solder process
Dispensed solder paste on the pads of a QFPs
A printed circuit board (PCB), also called printed wiring board (PWB), is a medium used to connect or "wire" components to one another in a circuit. It takes the form of a laminated sandwich structure of conductive and insulating layers: each of the conductive layers is designed with a pattern of traces, planes and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. Electrical components may be fixed to conductive pads on the outer layers in the shape designed to accept the component's terminals, generally by means of soldering, to both electrically connect and mechanically fasten them to it. Another manufacturing process adds vias, plated-through holes that allow interconnections between layers.
Printed circuit board of a DVD player
Part of a 1984 Sinclair ZX Spectrum computer board, a printed circuit board, showing the conductive traces, the through-hole paths to the other surface, and some electronic components mounted using through-hole mounting
Proximity fuze Mark 53 production line 1944
Through-hole (leaded) resistors