Yield and quality control

Which correctly describes the difference between the control limits of a control chart and a product's specification limits?

  1. AControl limits are set from the process's actual variation, while specification limits are set from the requirements placed on the product
  2. BControl limits and specification limits always have the same values
  3. CControl limits are set by the customer, while specification limits are calculated from process data
Show answer and explanation

Answer: A. Control limits are set from the process's actual variation, while specification limits are set from the requirements placed on the product

Control limits are lines calculated from the mean and variation of data when the process is stable, used to judge whether an abnormality has occurred in the process. Specification limits define the range allowed for the product, set from customer requirements and design. They are based on different ideas, so it is important not to confuse them.

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More Yield and quality control questions

  1. What is the correct order of the PDCA cycle used in quality control and process improvement?
  2. Which of the seven QC tools is the approach of dividing data into groups, such as by machine, operator or material, and comparing them to find the causes of differences?
  3. Which of the seven QC tools is a pre-prepared table of items to check that makes it easy to record and tally inspection results and defect occurrences?
  4. Which is the general explanation of the difference between a product's "quality" and its "reliability"?
  5. What is the approach called that emphasizes, when a problem occurs, going to the actual place, looking at the actual thing and confirming the actual situation?