[Whizbang]

Hey all,

So im pretty sure this isn't a machine issue but hoping you guys might have some insight. I am trying to machine some 6061 aluminum into a part for my 3d printer. My first operation is an adaptive clearing with a 1/2" roughing end mill. The end mill is only taking a 2mm cut at very conservative feeds and speeds yet while cutting on the first pass the tool holder is being pulled from the spindle collet. Has anyone had this issue, if so what did you do to remedy?

And FYI the first time I noticed it the tool came out of the holder so I switched holders then it pulled the holder from the spindle collet. And yes I did check that the spindle collet was tight and secure

Attachment 292278

Attachment 292280

Thanks,
Whizbang

[LeeWay]

You are milling upside down.

Kinda hard to get the coolant to the right spot that way.

You need to periodically clean both the collet and the shafts on the TTS. Then lightly lube the outer taper on the collet as well as the threads and draw bar. Careful not to allow any lube in the slots. I use a butterfly impact when I run my 1/2" end mills. The lever draw bar will not hold them well enough unless everything is perfect. We clean our tools about once w eek or two, so rarely is it perfect. It will pull out if it's just a bit dirty or dry with just the lever draw bar.
I don't have any issues with the smaller tools though.

I have never had one come loose from a set screw holder or an ER collet holder.

[kvom]

Post your conservative F&S, When I entered HSS 1/2" 2-flute rougher, 2" DOC, .08" axial engagement in G-wizard, I found that the HP rating and deflection can increase rapidly with modest feed increases.

I don't use TTS, but when I use 1/2" carbide tools I've suffered tool pullout. I bought a good quality 1/2" R8 collet just for this use to replace the one in my average Chinese collet set. Smaller tools and HSS haven't posed the same issue for me.

You may get the same elapsed time with less cutter force by reducing axial cut and increasing feed&speed.

[SCzEngrgGroup]

First, what are your cutting parameters? RPM, Depth, Width, Feedrate. Looks to me like you're trying to do at least 1-1/4" depth, 0.080" width, which is not realistic with that machine, unless you're going quite slow, which defeats the whole purpose of using adaptive clearing.

How are you tightening the drawbar? If properly tightened, you will NEVER see pull-out - the spindle will stall first. With TTS "properly tightened" means 25-30 ft-lbs on the drawbar, which means cranking pretty hard on the drawbar with a long wrench. I use adaptive clearing a LOT on my Torus Pro, and have never once had pull-out, even when running the spindle at near 100% power. Most of my roughing is done at 1/2" depth, 0.05" width, well over 100 IPM using a 1/2" 2-flute.

If you remove the toolholder, does the collet fit up inside the spindle far enough that the face of the collet is well ABOVE the spindle nose? If not, then either the collet is tool large, the spindle bore too small, or the set-screw in the spindle is sticking too far inside the spindle. This has been a problem with some TTS collets, both real Tormachs and third-party ones.

Regards,
Ray L.

[Whizbang]

So, first off,sorry about the photos being upside down. They viewed upright in the post preview.

The 3 flute bit I am using has an actual OD of .496" and had a stick out of 1.24" from the tool holder. My depth of cut was 30mm (1.18") and the cutting width was 2mm (.080"). My feeds and speeds were 4000rpm, feed rate: 17.383 ipm, 519and which according to GWizard yielded .365 hp and .0001" deflection.

I made sure the collet was fully seated and that the tool holders were also fully seated. I can't tell you what torque I had it tightened to but it felt very tight and the wrench I use has decent leverage.

[SCzEngrgGroup]

OK, so you're running very low feedrate, which pretty much negates the benefit of using adaptive roughing. However, you should not be getting pullout. So,either the toolholder shank/collet are "slippery", the collet taper is NOT "slippery", or you're not tightening it enough. Thoroughly clean and dry the toolholder and collet (inside and out) - Acetone works well. Then put a THIN film of anti-sieze on the collet taper. Tighten the drawbar TIGHT.

I would STRONGLY recommend using a more appropriate width/depth of cut, and getting both the RPM and the feedrate up. Using the same tool, 1.0" DOC, 0.05" WOC, HSMAdvisor gives me 6000 RPM at 57.5 IPM, and I'm quite sure my Torus Pro will do that. You must have the slider in GWizard set well over to the "turtle" side...

Regards,
Ray L.

[kvom]

If he has the older NM200 like mine 4000 is max RPMs.