Originally Posted by
mflux_gamblej
I've trashed 4 x 1/4" and 1 x 1/2" endmills on the same workpiece.
My most recent attempt was:
1/4" endmill, 3850 RPM (252 SFM), 10.78 in/min xy feed (0.0007 in/tooth), 7.7 in/min z feed (0.0005 in/tooth). Step over is 20% of tool diameter (0.0500"), plunge depth is 0.0250". With these settings, I managed to mill 2 pockets, on the second the bottom of the pocket doesn't look quite right (very dull tool), on the third the tool just got rounded off and started eating further into the tool, now it is around 1/4" shorter and obviously trashed. These settings are based on SFM recommendations from maritool (backed off as they recommend for deep profiles) in addition to some notes I have from a friend who mills 304 all day on a HAAS VF2SS.
I've also tried around 1000 RPM, around 4 xy feed, 1 z feed, the tool actually died much faster this way. The material is 304 stainless steel, the cutters are TiALN coated carbide from MariTool.
My mill is an old interact 1 mk 2, 9.5 HP, workpiece is clamped hard to the table with a waste plate of Al underneath so I can mill through into that. I get a lot of chatter at slightly lower RPMs (around 3000-3300), almost no chatter around 1000 RPM, and pretty much no chatter up at 3850 RPM.