A method of calculating limits of dimensional variation

GT V01 1960 121-129

Standard Telephones and Cables Ltd., Paignton Dimensional variation is at the root of many problems arising between producer and customer in the glass industry. It is usually possible for a designer to prepare a satisfactory specification by observing certain generally accepted quality standards, but in difficult situations (e.g. where special limits of accuracy are required) it is not always easy to decide what allowance should be made for the various sources of variation. A graphical representation of the random and systematic sources of variation enables the designer to see his problem more clearly, and by using statistical principles he can forecast the probability of success of his design. The problem of a tubular glass bulb is used for illustration and the effects of variation of mean diameter and mean wall thickness and of siding and ovality are dis- cussed. Limits of accuracy are calculated for a specific example

S. J. Morrison & M. Symons