Process Capability: Formulas & Implementation

Juran Knowledge

How do you find process capability?

  1. Identify the process subjects for measurement.
  2. Establish units of measure, sensors, and upper and lower specification limits for the selected subjects.
  3. Operate the process through a number of cycles. (A minimum of 40 observations without any assignable causes are usually needed.)
  4. Identify and remove any observations that are out of control as the result of assignable causes.
  5. Construct a histogram of the remaining observations for each subject.
  6. Evaluate the process capability visually.
  7. Calculate the Cpk index for each process subject. CPK Index Formula
    The index must, at a minimum, equal 1. 0. Most processes should have a minimum index of 1.33.
  8. If the process is not capable, identify and eliminate the root causes for excessive variability.

Process Capability Formula Example


 

For more information on process capability and how Juran can help you leverage it to improve your quality and productivity, please get in touch with the team.

 

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Author: Juran

For the past 75 years, Juran has been an industry leader in performance excellence. We are your on-demand team of trainers, coaches, and expert consultants. Built upon the philosophies laid out by Dr. Juran, the father of quality, we put you on the fast track to results by designing improvement initiatives that actually work. We aim to help all organizations achieve the highest quality of products, people, and processes, and we understand the importance of transferring our knowledge to your team to guarantee the success of your program in the future.