In the Loupe TV: Diving Into Chip Thinning
A common phenomenon that many machinists experience at the spindle is chip thinning. This occurs when step-over is less than 50% of the diameter, which causes the chips to be formed less than what the tool is programmed to remove. Tooling is specially engineered for certain chip thickness, so it is essential to ensure it is correct, to avoid premature tool failure. Join In The Loupe TV’s “Cutting Tool Counselor,” Don Grandt, as he provides tips and tricks on how to simplify the process of combating chip thinning, so you can get the most out of your CNC tooling.
I am not sure why the SFM is increased. Maybe it CAN be, but it has nothing to do with chip thickness compensation, which would be the same thickness at given step over and forward motion per tooth regardless of tool RPM. Can the tool really operate well at 2x or 2.5x the table SFM/RPM without overheating??
Now consider an extreme case. Desired chip thickness is .0025, and step over is .0025 which is 1/2 pct of half inch tool diameter. I think we would find that the forward speed would calculate to the tool rolling along the surface at extremely high forward speed, not sweeping the cutting edge back at all and not cutting the surface, just marking a series of lines .0025″ into the material as it rolls along! Of course we CAN remove 2.5 thou from a surface, using a reasonable feed rate, just the chip thickness will be a lot less than .0025 in..