Nair, K. Balachandran; Chuck, Chi Dat (1990, ASQC) Hong Kong Polytechnic, Hong Kong
The paper narrates the application of some commonly used tools in quality control as well as improvement of Printed Circuit Board Assemblies (PCBA) at a Hong Kong factory of a multinational company. The work was carried out by the second author who was a senior student on industrial attachment, under the direction and guidance of the first author.
Two cases of application of SPC are covered. The first one concerns the occurrence of defects during the Wave Soldering process of PCBA manufacture. In this instance, once the existence of the problem was identified, its source could easily be traced. Necessary steps were taken not only to correct the situation, but to prevent the re-occurrence of the problem. The second case involved quality problems at the Surface Mount (SMT) stage. These could arise from at least three sources. A systematic multi-stage investigation was therefore undertaken which lead to pinpointing the origins of the problems. Means/methods for correcting and preventing them from reoccurring were developed and implemented. In both instances, proper attention was devoted to ensure the removal of the source of the problems in an enduring manner.
As information about the nature and importance of the factors affecting the wave soldering process appears to be scant, a model is postulated using a set of assumptions. Computer simulation of the process applying this model was carried out next with the aid of a three-factor EVOP analysis. A description of the method used for yield maximization is presented in the final part.
As a result of the work carried out in accordance with the first part of the paper, a substantial reduction in the average defect rate was achieved. But the work of assessing the process optimization routine using the EVOP remains unfulfilled as the industrial attachment was short. It is hoped that this will be taken up by some interested party.