Chapter CS, Problem 8.4CQ

Summary Introduction

Case summary:

Company T manufactures machined steel parts according to the specification of the customers. They received an order for 5000 steel pusher rods. The rod must be machined 0.500 ± 0.005. The parts that produced must between 0.495 and 0.505 to satisfy the customers with their specification. The sample values made on two different machines with two different operators were given. The sample of 5 parts for 6 runs is 30 sample parts. Each operator-machine combination has 30 sample parts. It is used to establish the average range and average mean.

The problem in statistical quality control can be identified using the case. The upper control limit, central line, and lower control limit helps to determine whether the process is under the control or not. The operator-machine combination can continue making the parts, if the process is under the control.

To determine: Whether all the parts produced by the in-control processes will meet the specification.