41. Processing Quality Control

The processing quality control of adhesively bonded joints in actual production lines is discussed in this chapter. To improve the yield ratio of products, a scientific approach based on both probabilistic design and statistical treatment are indispensable. In addition, control of environmental conditions and materials is also very important. For the purpose, a realistic trial-and-error approach should be done to meet any demands or to solve problems occurring in the production. Investigation of reasons decreasing joint strength is another key point that should be done. The strength decrease occurs often due to mechanical or chemical mismatch of adherends and adhesives. The surface treatment of adherends is important too. Inspection, which can be carried out easily, is desirable in actual production lines.

Process design should be done appropriately to improve the efficiency and the economy of the lines, and to increase the yield ratio of products. Parallel processes should be avoided if sequential processes can be adopted. Reduction of operator’s tasks is another important issue. The concept of foolproof should be introduced in the process design.

Proper adhesive selection is vitally important, not only for good strength, but also for increasing operation efficiency. New types of adhesives have been available to meet the demands to control the process easily. The education and training of operators is also an essential issue. Operators should learn standard procedures to perform their work appropriately. The necessary information should be exchanged properly.