Determining when a tool has reached the point when it’s time to re-sharpen takes a visual examination of the cutting edge. Inspecting the cutting edge will determine if the running parameters are adequate for optimal results.
This drawing is an example of when it’s time to re-grind a tool. Pay close attention to the margin, smearing, or a need to be cleaned-up during the re-grind process to ensure the tools’ repeatability.
If the outside corner is rounded, it usually means that the SFM is too high and the RPM should be lowered in 10% increments until the wear is along the cutting edge and the corner remains pristine.
If there is evidence of chipping or cratering along the cutting edge point, the feed rate should be lowered.
If there is build-up on the OD, it is usually a result of too much heat and the concentration levels should be checked to maintain 10% – 12%.