Mcclelland, H. T. | Engineering Papers

NASA NTRS1994

Process capability determination of new and existing equipment

The objective of this paper is to illustrate a method of determining the process capability of new or existing equipment. The method may also be modified to apply to testing laboratories. Long term changes in the system may be determined by periodically making new test parts or submitting samples from the original set to the testing laboratory. The technique described has been developed through a series of projects in special topics manufacturing courses and graduate student projects. It will be implemented as a standard experiment in an advanced manufacturing course in a new Manufacturing Engineering program at the University of Wisconsin-Stout campus. Before starting a project of this nature, it is important to decide on the exact question to be answered. In this case, it is desired to know what variation can be reasonably expected in the next part, feature, or test result produced. Generally, this question is answered by providing the process capability or the average value of a measured characteristic of the part or process plus or minus three standard deviations. There are two general cases to be considered: the part or test is made in large quantities with little change, or the process is flexible and makes a large variety of parts. Both cases can be accommodated; however, the emphasis in this report is on short run situations.

Mcclelland, H. T.↗

NASA NTRS1992

Laboratory experiments from the toy store

The following is a laboratory experiment designed to further understanding of materials science. This material could be taught to a typical student of materials science or manufacturing at the high school level or above. The objectives of this experiment are as follows: (1) to qualitatively demonstrate the concepts of elasticity, plasticity, and the strain rate and temperature dependence of the mechanical properties of engineering materials; (2) to qualitatively demonstrate the basics of extrusion including material flow, strain rate dependence of defects, lubrication effects, and the making of hollow shapes by extrusion (the two parts may be two separate experiments done at different times when the respective subjects are covered); and (3) to demonstrate the importance of qualitative observations and the amount of information which can be gathered without quantitative measurements.

Mcclelland, H. T.↗