When taking various cuts, what is the effect on tool life, surface finish and dimensional accuracy?

Question

to include: trial cuts, roughing and finishing cuts.

(engineering)

Answer 1

That's hard to answer, typically you are using different cutters for different applications, e.g. you don't use a roughing end mill for finishing operations etc., feeds and speeds are different for roughing vs. finishing and so on...

Answer 2

There are a lot of variables to deal with, Material properties being the most significant , Proper cutting conditions depend on a ratio of depth of cut and surface speed of the tool, Tool life is based on maintaining that proper ratio as best you can. Dimensional accuracy is also affected by maintaining that ratio , ( Hence repeatability ) generally a finish cut involves higher speed and slower feed, your trying to achieve a closer distance point to point between the crest or high points of the finished surface and less tearing of the surface. A trial cut is a simulation you preform using a set depth of cut at a certain speed and feed you measure to see how much deflection you get , you dont always remove .025 just because you dial it off, because of the deflection and parameters you set. Better surface finish gives you closer distance point to point between the high points of the cuts, and results in more bearing surface which lasts longer up to a point, much has to do with calculated lubrication properties as designed into the part being machined . There is an effect called work hardening which results from improper choice of cutting parameters for a given material . In effect you end up "Mushing" or "Smooshing" the material and folding it over on itself which generates heat which isn't good. instead of cutting nice finely spaced microscopic grooves( Surface finish is measured in (RMS) Root Mean Squared