PMAPTM Articles/Papers

by Jerry L. Everhart – JTI Systems, Inc. and Georgia L. Harris – NIST Office of Weights and Measures This paper describes how the Process Measurement Assurance Program (PMAP)2 is used in the U.S. State metrology laboratories to provide uniformity among the laboratories in measurement control, uncertainty evaluation, control charting, and assurance of standards accuracy and traceability. The program provides a method for electronic submission (via e-mail or diskette) of control charts and standards data in a standardized format for NIST, Office of Weights and Measures (OWM) evaluation. The methodology of PMAP and how it applies in a comprehensive quality management program for State metrologists can be applied to other metrology laboratories and systems.IntroductionThe NIST Office of Weights and Measures provides oversight for the U.

byJohn P. Clark and A. Harper Shull – Westinghouse Savannah River CompanyAiken, South Carolina 29808 The information contained in this article was developed during the course of work under Contract No. DE-AC09- 89SR18035 with the U. S. Department of Energy. By acceptance of this paper, the publisher and/or recipient acknowledges the U. S. Government’s right to retain a nonexclusive, royalty-free license in and to any copyright covering this paper along with the right to reproduce, and to authorize others to reproduce all or part of the copyrighted paper WSRC-MS-96-0405.IntroductionIt is important to remember that measurements are estimates of parameters of interest and these estimates contain random and systematic errors. These errors decrease our certainty of knowing the “true value” of the material measured. Hence, all

by Richard B. Pettit – Primary Electrical Standards Department Sandia National LaboratoriesAlbuquerque, NM 87185 SAND96-1241, Unlimited Release, Printed May 1996 Distribution Category UC-706 IntroductionThe current emphasis on manufacturing high quality products requires ensuring that the product meets its specifications with regard performance, reliability, and competitiveness. For this determination, one must measure all of the important product attributes in order to quantify the quality of the product. During manufacture, the product data are usually analyzed using standard statistical methods, such as statistical process Control (SPC) or Six-Sigma techniques [1], in order to minimize product variation due to process variables. This leads to continuous improvement in the production process and the resulting product. However, the product data accuracy can not be better than the accuracy (or uncertainty)

by Jerry Everhart – Vice President of Quality and Measurement TechnologiesJTI Systems, Inc. Rio Rancho, New Mexico IntroductionUncertainty determination of mass measurement is required for both the calibration of mass standards (weight calibration) and for products that are quantified with mass measurements. An understanding of the uncertainty components of mass measurements as well as the methods of data collection and analysis is often more critical than the more often discussed and published equations of uncertainty determinations. This understanding is crucial to evaluating mass measurement results against tolerance classification or product specifications.Calibrating and making adjustments to mass standards without this understanding causes less accurate standards. Manufacturing products by making adjustments to the mass quantities can provide customers with products that are out of design specifications if

by Jerry Everhart – Vice President, Quality and Measurement TechnologiesJTI Systems, Inc. This article was printed in CAL LAB Magazine, issue January/February 1997. A high degree of competitiveness in the national and international manufacturing markets has created a demand for process controls that build quality into products, rather than relying on inspection to sort out costly rejects. This article describes a process measurement assurance program (PMAP) that determines and controls measurement errors (uncertainties) as the product is produced. The results of this program coupled with production statistical process control (SPC) determine the product values with a known certainty. When the measurement error is determined along with the product variation, the product error is known and further inspection activities are greatly minimized or eliminated.Need for Process