A method is presented to determine the number of first-article castings that must be run and inspected to insure that pattern dimension changes are necessary and accurate. Insufficient information from too small a sample size can lead to unneces- sarv pattern adjustments, improper pattern dimensional changes and extra cost. The methodology presented is based on process variation and cast feature tolerances. These factors, along with process capability and Gage repeatability and reproducibility (Gage R&R) considerations, are discussed in detail.
展开▼
