Process Control and Capability
The first step for process improvement is stability. We analyse this with Statistical Process Control . As a result of this analysis we may find out-of-control situations due to special causes. We need to resolve these causes to make the process stable. Stability means the process is behaving in a predictable way but it doesn't necessarily mean it meets the customer expectations. To find out to what extent is the process able to meet the customer expectations we measure Process Capability . Descriptive Statistics with Excel Download a copy of Excel file Capability.xlsx from OneDrive on to your PC to run it. In sheet Diameter we have placed in column A our data consisting of 500 measurements of a critical diameter. After being confident that our process is stable we can characterize it with descriptive statistics in Excel Data Analysis: These are the results: basic statistics of our data Frequency Distribution Histogram The histo...