Implementing SPC at a Large Manufacturing Plant


Evans, Jerry L.; Gizzi, Leo R.   (1991, ASQC)   Hercules Aerospace Company, Radford, VA

Annual Quality Congress, Milwaukee WI    Vol. 45    No. 0
QICID: 9734    May 1991    pp. 740-745
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Article Abstract

This paper presents the methodology used by the Radford Army Ammunition Plant (RAAP) to achieve Statistical Process Control (SPC) in manufacturing areas.

The SPC and Quality Engineering (QE) groups at RAAP are responsible for preparing specific SPC plans, monitoring SPC activities, and performing essential SPC studies, including: Process Review and Analyses, Process Capability Studies, Inspection Capability Studies, Preparation of Control Charts (format, limits and center lines, Modifying Control Charts, Data Management and Analyses, Identification of Problem Causes and Recommending Corrective Action, and Monitoring Corrective Action. The procedures used to unify the use of SPC at RAAP required:

  1. establishing an SPC program;
  2. process review and analysis,
  3. process capability studies,
  4. cause-effect diagrams, and
  5. preparation of control charts.
Training helped overcome some negative attitudes and confusion about specific job responsibilities prevailed during the early stages of SPC implementation, and the following benefits were realized from applying statistical methods:
  1. increases of more than 50% in product yield along with reduced rework for selected products;
  2. an increase in probability of meeting final product specifications from 70-80% to greater than 99% for products difficult to produce;
  3. a reduction of approximately 6% in failure costs, resulting in a savings of $12-15 million per year based on a $100-250 million operating contract.


Aerospace industry,Capability study,Case study,Cause and effect diagram,Control charts,Defense industry,Manufacturing,Process analysis,Statistical process control (SPC)

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