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Industrial Engineering & Manufacturing vocabulary · Quality Control and Assurance

Control chart

Meaning in industrial engineering & manufacturing, with examples

nounCommon term

In industrial engineering & manufacturing, control chart means: A graph that shows measurements of a process over time, with a center line and upper and lower control limits, so you can see whether the process is stable.

In Turkish: kontrol grafiği, kontrol kartı, kontrol diyagramı

How it is used

Developed by Walter Shewhart in the 1920s. Common types are X-bar and R charts for measurements and p-charts for defect rates. Points outside the limits, or unusual patterns such as a long run of points on one side of the center line, signal a special cause to investigate.

Example sentences

  1. The control chart shows the diameter drifting upward since the tool change.

  2. Two points on the control chart are above the upper limit, so stop the machine and call quality.

Common collocations

  • X-bar and R chart
  • upper control limit
  • plot on a control chart
  • out of control
  • statistical process controlA method of monitoring a process with statistics, usually control charts, to spot unusual variation early and keep the process stable. Shortened to SPC.
  • variationThe natural differences between the results of the same process, for example small changes in the diameter of parts made on the same machine.
  • standard deviationA number that shows how widely values are spread around their average; a small standard deviation means the results are close together. Its symbol is σ (sigma).
  • process capabilityHow well a stable process can produce parts within the specification limits, usually expressed with indices such as Cp and Cpk.

More terms: Quality Control and Assurance

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