O'Reilly logo

Statistical Process Control for Quality Improvement: A Training Guide to Learning SPC by James R. Evans - Department of Quantitative Analysis and Information Systems, College of Business Administration University of Cincinnati

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

3 Control Charts

3-1. Introduction to Variables Control Charts

Suppose you were operating a machining process that drilled a hole with a specification of .500 plus or minus .003 into a part. That is, the specification is .497 to .503. The quality characteristic that is important is the inside diameter of the hole. Now suppose you measure and record the diameter of every part that is produced. You might find the following sequence of measurements for eight consecutive parts:

.501 .500 .498 .500 .499 .501 .500 .499

As we discussed in Chapter 1, there will be some variation from part to part due to materials, temperature, and so on. We can see this in these measurements. Most are close to the nominal value of .500 and within specifications.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required