[FuriousGeorge]

I’ve just started running flood coolant and my ATC together and have begun experiencing pull out on some of my tools. I’ve followed Tormach’s guidelines on preventing collet slip and am fairly certain that the reason for the pullout was a TTS shank wet with coolant. After the pullout occurred, I checked all of my tools in the ATC and all were coated with coolant and fairly slippery.

Has anyone else with an ATC experienced similar issues when using flood coolant? I’m thinking about building some type of splashguard for the ATC itself, and would love to hear if anyone else has done that/ found a simpler solution.

The cut that caused pullout was a radial 0.075" DOC .4" WOC at 4575 RPM and 90 ipm with a 0.5” 3 flute HSS rougher in 6061, fyi. I’m not a very experienced machinist, but that seems like a pretty wimpy cut to cause collet slip on its own.

Thanks,
FG

[GJeff]

Is the coolant being flung off your spindle or actually splashing from the pressure? The default coolant system doesn't seem to have enough force to do any real splashing but regardless the spindle does seem to like to spin coolant with an upward trajectory.

I wonder if you can build a small spindle shoe that is compatible with the ATC. Perhaps with just enough coverage to keep the coolant from being flung upwards.

[Steve Seebold]

I’ve just started running flood coolant and my ATC together and have begun experiencing pull out on some of my tools. I’ve followed Tormach’s guidelines on preventing collet slip and am fairly certain that the reason for the pullout was a TTS shank wet with coolant. After the pullout occurred, I checked all of my tools in the ATC and all were coated with coolant and fairly slippery.

Has anyone else with an ATC experienced similar issues when using flood coolant? I’m thinking about building some type of splashguard for the ATC itself, and would love to hear if anyone else has done that/ found a simpler solution.

The cut that caused pullout was a radial 0.075" DOC .4" WOC at 4575 RPM and 90 ipm with a 0.5” 3 flute HSS rougher in 6061, fyi. I’m not a very experienced machinist, but that seems like a pretty wimpy cut to cause collet slip on its own.

Thanks,
FG

At 4575 RPM and 90 IPM, you're not actually cutting material. You're just pushing it out of the way. Slow your feed down to 40 IPM and you'll achieve much better results.

[SCzEngrgGroup]

That cut is not all that "wimpy". That cut is about 2.7 cu. in./min. MRR, which is not all THAT far from the limits of what any 1.5HP machine can be expected to do. Even so, you shouldn't be getting pull-out.

Regards,
Ray L.

[FuriousGeorge]

GJeff,

You’re absolutely right, the coolant is splashing of my spindle rather than the work piece. My plan right now is to make a sort of half shoe attached to a spare adjustable coolant hose. This way, I can make the shoe as small as possible and just adjust its position if I’m not getting the proper coverage. I’ll get around to it sometime next week and I’ll post pictures when I do.

Steve,
Thanks for the advice, I’ll try running the cut at a lower feed. Just out of curiosity, what is the effect of “pushing” material? I know it produces a bad finish when I cut that fast (I’m roughing, so I don’t particularly care), does it reduce my tool life as well?

[SCzEngrgGroup]

Your feed and speed are exactly where they should be for that DOC and WOC, and your chipload is 0.006", which is just about ideal for that tool. But I'm wondering why you cut wide and shallow, rather than narrower and deeper, so you actually use more of the tool? You'll end up tossing the tool when only the tip is worn out, while the other 98% is still like new. If the goal is rapid removal of material, I'd go deeper, and, if necessary, a bit slower, and you should be able to increase your MRR, and get more use out of the tool. If you went with 0.2" WOC and 0.2" DOC with basically the same RPM and feed, you'd still be at only 1.2HP, but you'd up your MRR to 3.75 cu. in./min. That will also give you less tool deflection, which will help surface finish.

Regards,
Ray L.

[btu44]

I run 1/2" 3 flutes in aluminum almost exclusively.

For roughing contour I use RPM 3200, 50 IPM, .15 WOC, .35 DOC
For slotting 3200, 37 IPM, .15 DOC

Were you getting any chatter during the cut? Generally if I get heavy chatter than I had a tool pull out.

Barry

[BAMCNC.COM]

YouTube has a video of a guy who made an ATC shield, I'm on phone or I'd link you. Also are you sure your tension is correct on your drawbar?

[beanbag]

Tool pullout is also caused by the precession of the tool as it is being deflected. So the less tool stickout you have, the lower tendancy to pull out. If you are already using the set screw endmill holder, that's about as short as you can get.

[Steve Seebold]

That's not always true. I can cause significant pullout by simply pushing my tool too hard.