Surface metal contamination on tool components - A case study for evaluating acid extraction ICP-MS measurement process

Measurement system analyses were conducted for acid extraction ICP-MS analysis for trace metal contaminations on the surface of ceramic test coupons. The results revealed that a casually designed Gage R&R study neglecting the nonreplicable nature of the analytical process could lead to erroneous conclusions, e.g. combined Gage R&R consumed 84% of Ca tolerance, which was much inflated by the inherent part-to-part variations. With necessary adjustments to the experimental design and data processing, accurate evaluation could be achieved and the consumption of Ca tolerance was actually 15%. This work proved that careful considerations must be given to the conditions and boundaries of the measurement system analysis in order to avoid pitfalls and to attain accurate results so variation sources and improvement opportunities of the manufacturing processes could be correctly identified.