Application-Oriented Description of the Quality of Electronic Components (ppm Concept)

摘要

Traditionally the production quality of components is described by “acceptable quality levels” (AQL). Agreements, referring to this principle, determine the acceptance or refusal of batches that have been sample tested. An acceptable quality of level is interpreted as a tolerated limit. In reality true values of quality must be better. An AQL value cannot define a real quality level. Furthermore, increasing requirements for component quality lead to low figures for the permissible amount of faulty devices in batches, and the method of sample testing becomes insufficient.For these reasons it seems to be of major importance to establish a better standard for the definition of quality. The application oriented description of quality data offers a possible solution. A good exchange of experience between supplier and user, based on a close and quality loop, is necessary.For contractual purposes AQL values remain important, but their meaning needs a new interpretation.