The development of an automated rework cell for printed wiring assemblies

As the piece cost of completed circuit boards increases and production quantities decrease, rework of defective boards has become an important part of the production process. Surface mount component lead pitch has also been decreasing, which has required increased training and skill level of the rework operators. Automated rework provides a more cost-effective and reliable solution to these problems. The function of the rework cell is to remove and replace individual surface mount components from a fully populated circuit board without damaging the board, surrounding components, or solder joints of the surrounding components. The solder used is tin-lead with a eutectic melting temperature of 183° Celsius. It encapsulates the steps of circuit board assembly, which is normally done by separate machines in an assembly line, into a single machine, as well as add two additional operations. Further, the tooling must be able to handle a wide range of component sizes and pitches creating an operating environment that approaches a product batch size of one