Heaphy, Maureen S. (1988, ASQC) The Transformation Network Inc., West Bloomfield, MI
Since the early 1970's, the American buyers have become more aware and critical in their purchasing decisions. Industry, in response, has been forced to change the way they do business if they want to stay in business. The objectives of successful companies are led now by customer satisfaction and never-ending improvement. At the operational level, the emphasis is changing from detection to prevention, and from a tolerance orientation to a target dimensioning philosophy. Meeting the blueprint tolerance is no longer sufficient; reduced variation is now required. A necessary part of this change is the integration of Statistical Process Control (SPC) into everyday operating activities. The need for, and the key elements of this transformation of American management strategy are contained in the teachings of Dr. W. Edwards Deming. To assist industry and service organizations in this change, the Automotive Division published a manual on SPC. A review of this manual, which was based on General Motor's SPC Manual, will be presented. Topics covered include measurement system analysis, process analysis, problem prevention and continuous improvement. Measuring equipment is subject to variation. Therefore, an analysis of a process cannot be meaningful unless the measuring instruments used to collect the data are both accurate and repeatable. If instruments are not properly calibrated for accuracy, a systematic variation or bias may result. A similar condition (reproducibility) could occur if different individuals use the same equipment to perform the same measurements. Another type of variation is caused by conditions built into the instrument itself such as internal friction. This variation (repeatability) occurs in measurements taken in a series of repeated, identical checks. Repeatability is sometimes referred to as precision in other literature. Certain key techniques needed to evaluate these types of variation are discussed.
Statistical process control (SPC),Automobile industry,Gage Repeatability and reproducibility studies (GR&R)