Improving MRR 304ss endmill

I have a setup that is working well, but the tool is lasting VERY long so I'm ready to trade off life for higher MRR.
(I can wreck some things in the pursuit of a long term improvement.)

Specs:
HAAS ST25Y lathe
BENZ radial live tool, ER32 collet
High flow flood coolant mixed at 10%
ISCAR FINISHRED, 1/2 endmill, 1/16 cham
4 flute (2 rough + 2 finish), 1" cutter
1.4" total stickout
STOCK:
-3" tube, 3/8 wall, 304SS annealed
-no mill scale (removed in prior step)
START CONDITION: 5/8 through hole
OPERATION:
ROUND COUNTERBORE POCKET
1.698" DIA x 0.300 DEEP
O-ring face on floor of pocket
METHODOLOGY:
Spiral passes with constant RDOC
CURRENT PARAMETERS:
-375 SFM
-RDOC 0.1" (20%)
-Feed 0.0035 IPR
-Finish: flawless / o-ring ready
CURRENT TOOL LIFE:
Still waiting. Hundreds of holes no change.
No signs of heat issues.
No chipping

This is obviously not as rigid as a heavy mill, but it's really solid and can certainly take more load.

To get higher MRR, what should I vary?
What would a high efficiency mill CAM suggest?

Thanks.

I'd try doubling your feedrate. 3.5 thou per rev on a 4 flute, 1" cutter seems light to me. Then again, I don't get to work with big stuff like that, so I may just be speaking out of my rear.

Those finishreds can take a beating. Your SFM is right there but you have room for some more aggression on that feedrate. Like TMP said, double it to start, but if it sounds good I'd be willing to bet you can go 3-4x what you're going on feed right now.

TeachMePlease said:

I'd try doubling your feedrate. 3.5 thou per rev on a 4 flute, 1" cutter seems light to me. Then again, I don't get to work with big stuff like that, so I may just be speaking out of my rear.

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I think he is saying it is a 1/2" diameter, 0.030" corner chamfer, 1" length of cut, 1.4" stickout end mill.

Everything looks like about where I'd start, though I'd use a SGS/Kyocera 5-Flute of the same basic design because that's what I keep in the tool drawer. I'm not sure how stiff the tubing is and I think you're saying it is only 0.075" thick once the pocket is in? I wouldn't increase ramp angle or anything to make sure I wasn't pushing material or chattering when I got to the bottom. If the chips look good and you aren't having harmonics issues I'd start with more feed per tooth and see what happens. Then maybe try more SFM and the same FPT and see? I doubt you're gonna run into HP or tool limitations before you run into other problems (chatter, too much heat in the material, etc.)

Rick Finsta said:

I think he is saying it is a 1/2" diameter, 0.030" corner chamfer, 1" length of cut, 1.4" stickout end mill.

Everything looks like about where I'd start, though I'd use a SGS/Kyocera 5-Flute of the same basic design because that's what I keep in the tool drawer. I'm not sure how stiff the tubing is and I think you're saying it is only 0.075" thick once the pocket is in? I wouldn't increase ramp angle or anything to make sure I wasn't pushing material or chattering when I got to the bottom. If the chips look good and you aren't having harmonics issues I'd start with more feed per tooth and see what happens. Then maybe try more SFM and the same FPT and see? I doubt you're gonna run into HP or tool limitations before you run into other problems (chatter, too much heat in the material, etc.)

Click to expand...

Oh yeah... I see now it's a 1/2" Endmill with .0625" corner chamfer with 1" flute length... I guess I was reading too fast...

dodgin said:

Those finishreds can take a beating. Your SFM is right there but you have room for some more aggression on that feedrate. Like TMP said, double it to start, but if it sounds good I'd be willing to bet you can go 3-4x what you're going on feed right now.

Click to expand...

When I got done my production run, I did some playing. Bumped speed another 20% and doubled feed. No issues. Next time I run these parts I'm going to try some braver numbers.