Appropriate measurement strategy for flatness

[[En...]]

Hello everyone.

I'm inspecting a steel plate to determine its flatness, but I'd like to know the most appropriate method, as this plate serves as a flatness control for some parts. Other companies in the same sector use these methods (Fig. 1 and Fig. 2), but we need to standardize our procedure.

Currently, I'm taking measurements as shown in Figure 1, creating horizontal and vertical polylines to better visualize the plate's curvature, using a speed of 10 and a total of 500 points.

  Fig. 1

  Fig. 2

I hope I can help.

Edited November 5

[[Ri...]]

Typically, I look at the surface and determine the method used to machine.

Was it a fly cutter creating a circular pattern (Or some other method with a circular pattern).

An end mill which you can see the pattern of cut.

I then create a scan pattern to cross section the cut pattern, I believe this gives me the best surface result for form/flatness.

In circular cut surfaces, I will offset my center line (usually in one axis only) and scan in the opposite direction of the cut pattern.