Analyzing Testing and Quality Control

From a practical aspect, when the expression quality control is use, we tend to think in terms of a good or excellent product. In industry, it is one that fulfills customer s expectations. These expectations or standards of performance are based on the intended use and selling price of the product. Control is the process of regulating or directing an activity to verify its conformance to a standard/specification and to take corrective action if required. Therefore QC is the regulatory testing process for those activities that measure a product s performance, compare that performance with established standards/specifications, and pursue corrective action regardless of where those activities occur. 

There are three phases in the evolution of most QC systems (1) defect detection where an army of inspectors tries to identify defects (2) defect prevention where the process is monitored, and statistical methods are used to control process variation, enabling adjust- 

When using the defect-detection approach to quality control certain problems develop. Inspection does nothing to improve the process and is not very good at sorting good-from-bad. Also, sampling plans developed to support an acceptable quality level (AQL) of 5%, for example, say that a company is content to deliver or reject 5% defects. 

To ensure that QC and testing procedures are followed a quality control manual should be implemented. It is a document usually setup in a computer s software program that states and provides the details of the plant s quality objectives and how they will be implemented, documented, and followed. 

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