Circular Lay Pattern Measurement: Smart, Accurate Ra Check

Summary for circular lay pattern measurement Discussion

Circular lay pattern measurement is the key issue in this thread: AL asks whether a 16 Ra anodized finish on Alloy-T6 should be checked perpendicular to the centerline or along the circular lay direction. The only answer, from Raj Bains, says most surface measurement systems are based on counting peaks and valleys over a set distance, so the reading should be taken across the grain of the pattern rather than with it. In other words, the practical guidance is to measure perpendicular to the lay to capture the roughness properly. The thread does not discuss special exceptions for anodized surfaces or circular lay beyond that general rule, so the advice is straightforward but brief.