What is the difference between subgroup size, subrange size, and sample size in WinSPC? You will find the answer to that question in this article. Subgroup Size/Subrange Size The term subgroup size applies to a variable characteristic and controls how many samples (also called data values or individual readings) make up a single plotted point … Continued

Inadequate measurement systems may result in inappropriate signals or even worse, charts that fail to detect important process changes. Thus, it is incumbent upon us to ensure that measurement systems are adequate for their intended use. Why Measurement Systems Assessment (MSA)? Effective use of data to drive decision-making requires adequate measurement systems. For example, when … Continued

You’ve identified a new system that will improve quality. Now, you need to show management a compelling financial ROI and get buy-in. Here’s how to gain support for your proposal. You’ve identified a new system that will improve quality. Now, you need to show management a compelling financial ROI and convince your colleagues that the … Continued

While I have been raising my kids and teaching them about life, they have been teaching me about how to be better at my job. Recently, I tried to explain to my children what I do for a living. “Just like Daddy helps you put together your blocks to build things, my job is to … Continued

The subgroup size formula and application are discussed in the conclusion of this two-part topic. Last month’s article focused on the conceptual application of appropriate subgroup sizes for X-bar charts. As we discussed, the purpose of control charts is to detect significant process changes when they occur. When the proper subgroup size is selected, X-bar … Continued

The key is to specify a subgroup size so that significant shifts are detected with high probability and that insignificant shifts are unlikely to produce a signal. Click here for Part II of this article The purpose of control charts is to detect significant process changes when they occur. In general, charts that display averages … Continued

Proper control chart selection is critical to realizing the benefits of Statistical Process Control. Many factors should be considered when choosing a control chart for a given application. These include: WinSPC Means Lower Costs and Higher Quality WinSPC is software to help manufacturers create the highest quality product for the lowest possible cost. You can … Continued

To answer that, we need to start off with what these capability indices represent. Capability indices characterize a process as compared to a specification. Now the important thing about these capability indices is that they are calculated on the individual measurements, and all of the indices require a process that is in control in order to mean … Continued

Process Control is proactive rather than reactive. The key elements of process control are outlined in this article. What is Quality? Ask people involved with the design and manufacture of a product the following question: “What is Quality?” Many, if not most, of the responses will be some form of the following: “Quality is ensuring that our … Continued