PROD1002: A company manufactures components with a critical dimension required to be in the range of 115mm to 116mm: Quality Engineering Assignment, UOG, UK

A company manufactures components with a critical dimension required to be in the range of 115mm to 116mm.

The gauge used to measure this dimension has recently returned from calibration. In order to test whether it is capable of being used to measure this critical dimension, a Gage Repeatability and Reproducibility (R&R) study is to be carried out. The measurements of 10 sample components, each measured twice by two different operators are given below:

Use this data, along with the Gauge R&R calculator to demonstrate that this measurement system is capable of assessing the components for the required dimension.

Historically, these components have been machined in batches of 5 on a Honzaki CNC vertical milling machine. The measurements of the last 20 batches made on this machine are given in the table below:

The company has recently bought a new Kawada CNC vertical milling machine to replace the Honzaki machine. The first 10 batches of components produced on the Kawda machine are measured and the results are given in the table below:

Calculate the Cp and Cpk process capability indices for both processes (you may assume that the data are normally distributed) and comment on which, if either, the process appears to be the better suited to this task. State what improvements to the process you might recommend, and who you would expect to be responsible for such actions.

Use an appropriate Statistical Process Control chart to assess whether there is any difference in the components produced by the two machines. (hint: calculate the x-bar and r chart control limits, plot the charts, and investigate for any “out of control” conditions)