The performance of widely used dimensional inspection equipment and systems used for investment casting dimensional inspection has been studied. Factors that influence dimensional variability have been identified and compared to the current ICI dimensional tolerance guidelines. In addition the role of tooling allowances and first-article inspection practices on assuring dimensional conformance have been established.
The poor dimensional repeatability and reproducibility of hand-held inspection devices, even when used by experienced operators, suggests that these measurement devices are of limited use by investment casters. Coordinate measuring machines (CMMs) require careful inspection strategies for success. First-article inspection strategies to minimize centering errors are described. Recommendations for the selection and use of appropriate foundry dimensional inspection equipment are presented.