[acliffhay]

Hey guys, first post as a Tormach owner!

I'm using a 2D contour operation to mill some slots in 360 alloy brass. Now that I have all of my programming bugs worked out, I've been playing with different end mills and such to get the most speed with the best finish possible.

I was using a .5", 2 flute carbide, 5000RPM's @ 46IPM. .1"DOC and the width of cut in the program is .5". Although that's kind of deceiving, based on the round tube. This left a nice shiny finish, but the burrs were horrendous no matter how I adjusted the F&S.

I picked up a 4 flute carbide and ran it at the same parameters, and it was quiet with almost no burrs. The finish was a little less than desired, obviously because the 4 flute needs to feed faster, but close to what i'm looking for. Using G-Wizard, the recommended F&S is 5000RPM, 90IPM. I'm a little nervous to push such a long cutter (4" OA, 2.5"LOC) that fast inside of the fixture.

With all of the experience on here, I was hoping for a little more advice to help me fine tune things.

Thanks,
Al

[Magnum164]

Welcome and congrats!

Can't help you though. I am interested to see what some of the more experienced do say as well.

[acliffhay]

Yeah, me too. Thanks for the reply!

I'm sure you can see I've crashed it into the fixture. The TTS ER tool holder was pulling out of the spindle on occasion, so, I'm hoping the power draw bar I just installed will help eliminate user error.

[Magnum164]

Yeah, me too. Thanks for the reply!

I'm sure you can see I've crashed it into the fixture. The TTS ER tool holder was pulling out of the spindle on occasion, so, I'm hoping the power draw bar I just installed will help eliminate user error.

I don't think I have heard of the TTS holder pulling out of the spindle. I have pulled a few drill bits out of the collet though.

I thought that was a planned crash into the fixture

Just for curiosity are you running coolant as well? I didn't see any in the picture. Wonder if some fluid could help with the grabbing as well?

[acliffhay]

No, I'm not running coolant. The carbide and the part stay perfectly cool, plus some of these tubes are 80" long, making a big mess if I had to run coolant. Now my biggest concern is if 45IPM is putting too much load on the spindle. It is getting quite warm.

There is quite a bit of force pulling on the cutter, and I've experienced the tool pulling out of the holder, but more often, the holder was pulling out of the spindle. All good now! The power draw bar is without a doubt a fantastic investment.

Is there any way to estimated spindle load without a load meter?

[Freddy Bastard]

I'm not sure how you could get rid of thoses burrs, but you could run another tool to deburr it. ie: a 3D contour with a lollipop tool.

What is it? Is it a flute?

[acliffhay]

It's a probe for taking samples of grain from silos, barges, wagons, etc.

The burrs are not a problem with a 4 flute mill. I'd like to push the feedrate to the upper end, but I'm still a little timid with my Tormach. Im fairly new to cnc machining, so it would be nice to know how much is too much. I'd hate to ruin the spindle.

[plasmator]

Brass can be especially 'grabby'. You may have better luck with negative rake tooling. If you do some Googling you should find quite a bit on the topic.