Looks like a good recipe!
My guess is that the low RPM is what caused the problems, as there's not enough power at those low RPMs. The original numbers might have been more appropriate for a geared drive, not a VFD?
Hello Forum,
I thought I would share my experience of CNC milling on my Tormach 1100 PCNC Series III some slots in a castellated steel nut. I bought a nice Harvey tools 1" woodruff cutter with .0625 r (.125) diam, Part # 937362. I was machining 4041 steel. I contacted Harvey and they were nice enough to help with some speeds and feeds as follows.
SFM: 200, RPM 764, Chip Load: .00138 IPT, Feed: 6.33 IPM, DOC: full at .125" WOC .080. (3 passes)
I tried these on a sample of 6061 to see how that would run but found it was very noisy. I felt I was getting a little chatter. Long story short I kept up with adjusting the speeds and feeds, # of passes and lead in and lead out until I got a good formula and ran the part in steel. The results were very good and so here is what I ended up with.
SFM: 220, PRM: 850, Chip Load .00138, Feed 4.00 IMP, DOC: .125, WOC 0.020" with 8 passes.
Hope this helps someone trying the same operation on their own.
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Looks like a good recipe!
My guess is that the low RPM is what caused the problems, as there's not enough power at those low RPMs. The original numbers might have been more appropriate for a geared drive, not a VFD?
Hello jwatte,
Yes, I think so too. The 1100 does not really like to cut steel.
By sharing my experiment hopefully someone else will not have to spend as much time as I did trying to figure it out. I keep a spread sheet of all
my materials and speeds and feeds for reference. Once i get a recipe that works I note it there for future use.
Thanks for sharing,
Cismontguy.
I was guessing both low rpms and the .08 woc would be a problem. I set woc thin to win when testing.
I break most tools because of woc. Last one I prepped and fixtured stock that was 1/2 wider then I specified in cam program. This resulted in near full woc on first pass down side of part. Mr bozoo went back to drawing board