Although I've been in the business for over 30 years, I've managed to never tap with a CNC mill before. New place I'm working at has a Fadal VMC4020 and I need to be able to do this with it. I don't know if the machine has rigid tapping or not... they've got a floating tap holder, so I figure I'll just pick a low RPM, calculate a feed rate that's just slightly slower than the pitch of the thread, and the floating holder extends just a bit by the time I get through the hole (10-32 through holes in 1/8" aluminum)... Right? Then an M05, followed by an M04, or what?
Well easy test go into MDI and type G84.2 enter start , and if the spindle spins 2 or 3 times and then holds it firmly in place ....... you have rigid tapping.
If the machine is in Format1 the code to do a 10-32 floating tap example
I've tapped thousands of holes on Fadal 3016, 4020 and 6030's. All of ours had rigid tapping option. Even without it you shouldn't need to add extra M05/M04 commands etc. It will still do the same thing with the G84 command minus the precise spindle encoder timing lockup. Basic code as follows should work with a 10-32 tap:
Question about CNC tapping
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