Machine Qualification - Getting Back to Basics


Ruonavaara, Christine J.   (1985, ASQC)   General Motors Corp., Troy, MI

39th Annual Quality Congress, May 1985, Baltimore, MD    Vol. 39    No. 0
QICID: 3141    May 1985    pp. 634-639
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Article Abstract

[Author's abstract]

Machine qualification is a process that involves evaluating a machine�s operation, inputs, output and current control system to determine its ability to product parts to specification. If the machine cannot meet requirements, action must be taken to correct this situation.

This paper presents a strategy and minimum requirements for plant-wide machine qualification activities. These activities are intended to be part of an ongoing quality program emphasizing machine evaluation, corrective action and continuous quality improvement.

A team approach is suggested for planning and conducting a machine qualification program. Such a team would be comprised of representatives from Process Engineering, Production and Quality Control. Others may also be asked to assist as required. Team responsibilities include: (1) establishing study priorities, (2) selecting characteristics to be studies, (3) planning and conducting studies, (4) resolving unacceptable machines and (5) implementing or expanding control systems.

The Machine Qualification Procedure consists of the following steps:

  1. Document Current Control System � This documentation includes any operating, setup or other instructions or requirements that are used to regulate the operation.
  2. Select and Evaluate Gaging � Gages should be variable type with gage error less than 20%.
  3. Verify Machine Set-up � The machine must be set-up according to process routing requirements.
  4. Conduct Capability Study - The short term capability study measures the inherent variation resulting from common causes.
  5. Conduct Performance Study - The performance study measures output variation due to both common and special causes and evaluates the effectiveness of the current control system.
  6. Classify Machine (Acceptable/Unacceptable) � The machine is acceptable is the capability ratio is less that 75% of tolerance and performance is centered and 100% within specification.
  7. Resolve Unacceptable Machine � Action must be taken to reduce output variation and assure conformance to specifications.


Automobile industry

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