New quality cost models to optimize inspection strategies

The main goals of quality management in all industries are customer satisfaction by delivery of defect-free products, the radical reduction of defect rates and also of quality costs in the production. Controlled technological processes are the most important way to reach these goals. These principles are standard in mechanical engineering and are in use with great success. But the properties in electronics productions are different from the properties in mechanical engineering companies. The processes are difficult and many environmental influences act on these processes. These influences are very strong, especially in case of producing small batches of assemblies (high mix-low volume). Some processes can become uncontrolled and the defect rates may go up. What can we do with these processes? This paper will give you an answer to this question. It describes quality cost models to compare the quality behaviors of different technological processes and of different inspection strategies (no inspection/statistical process control (SPC)/100% inspection). The quality costs are the "measurement system" to compare the different inspection strategies with each other. The costs are calculated by the use of mathematical models-the quality cost models. These models contain also the influence of pseudo defects and defect flow at the inspection processes.