Recoater tolerance is a measure of the minimum allowable clearance between the previous build layers and the recoater blade. It is expressed as a percentage of the depth of the powder layer. If the tolerance goes below the set value, a warning is issued. The default value of 20% means that the built part can deflect upward into a maximum of 80% of the new layer. The following figures can help clarify this concept.
In Figure a, 0.040 mm is allocated for the fusion of the next layer, and there is 0.040 mm on top of the build, which results in a 100% tolerance or clearance.
In Figure b, upward distortion of the previous build has taken up 0.006 mm or 15% of the tolerance, which results in 85% of tolerance remaining. This would be acceptable if your recoater tolerance was set to the default value of 20%.
In Figure c, there is a 0.0321 mm build overlap, taking up 81% of the tolerance. As a result, only 19% recoater tolerance remains and the system issues a warning message, as the tolerance is below the threshold of 20%.
In Figure d, the build of 0.050 mm exceeds the entire recoater clearance of 0.040 mm for the current layer, so it returns a warning and a calculated interference of -25%. This loss of tolerance would almost certainly result in recoater blade damage.