Surfacing iron

[MotorCityMinion]

Material is FC250, machining from billet, not cast. Lot of bosses and fillets on the part and some heavy chunking. Can all be roughed out with a 5/16 ball, finished with a 3/16 ball.

 

I think the iron is brittle, not ductile.

 

Here's the question: SFM, FPT? Can I remove this material fast? I'm thinking HSM Scallop for the majority of the part, .012/.016 step over to rough, approximately 1.0 Axial max DOC., then progressively smaller.

 

Any thoughts?

 

Thanks in advance, MCM.

[jeff]

It's Grey cast iron? am I correct?

Yes you can rip it off, just watch for edge chipping, it can happen.

 

Other than that,it's a little abrasive, so use tons of coolant, moderate rpm, and higher feed than normal.

enjoy the black soot that will be all over your hands

[MotorCityMinion]

Bump.

 

Thanks for the reply Jeff.

 

Machined large castings for years on Horizontals but primarily 2D, never surfacing. Ya, it's messy but not nearly the trouble of most steels and alloys. And I've seen too many Noobs chip or blow out edges because of dull tooling. I was just trying to get an idea on how fast I can really go. Machine is a Makino S56 with Heat Shrink tooling and a 20k spindle. If I can find my PW to photobucket, I'll post a pic of the part.

[Ron Branch @ Verisurf]

That small of tool I would think 1750 sfm for finishing would be no problem. Maybe .002 to .0022 feed per tooth.

[MotorCityMinion]

Thanks for the tip Ron.

 

I won't be able to hit 1750 SFM with a tool that small (3/16 or 5MM ball) and a 20K max spindle and I need to get some decent tool paths into a lot of 3mm Rads.

 

The Makino doesn't like top end at over 30 min. (according to the Machine tool reseller) so I usually program Max rpm at 18500 when doing longer runs just to be safe. I was thinking for RGH'ing, 5/16 ball, .014 step over, 18500k, and at .003 FPT that would get me right around 220. IPM. I'll watch out for chipping and leave .008 for finish.

[MotorCityMinion]

Found the PW to Photobucket. Part is aprx. 9" x 7 x 1.