[R.DesJardin]

It's not drawbar tension, or coolant, as much as its speeds and feeds. 1/2" cutters seem more likely to have this issue than any other size I've used. Yes dry tool shanks will help but I don't worry about it except when I load my ATC. After that I just run it. Roughing ends mills are a blessing then its run what you need for the length to finish. Adjust your speeds and feeds for finishing you can get what you need, use roughers for clearing. I have been running production with Tormach's for almost 7yrs, and no regrets. I bought one of the first PDB and ATC as they became available. They work hands down, no regrets and glad I didn't buy another brand.

[SCzEngrgGroup]

Some things worth trying:

Remove the Belleville springs, paying careful attention to their order, and orientation - How they are stacked makes a BIG difference in how they behave. Compare how they are stacked to the Tormach documentation. Clean them, coat them all with anti-sieze, then re-assemble. As Bellevilles compress, they must slide on each other, which cause cause a lot of friction.

It's also worthwhile to replace them, as some may be out of spec, or gone "soft". Just one bad one will reduce the tension of the entire stack.

Regards,
Ray L.

[SCzEngrgGroup]

It's not drawbar tension, or coolant, as much as its speeds and feeds.

I could not disagree more! If you have to modify HOW you cut to prevent pull-out, then you simply do not have enough drawbar tension. Period! I will say it again: With adequate drawbar tension, you will NEVER see ANY pull-out, even with very severe chatter.

Regards,
Ray L.

[Steve Seebold]

A question for those with tool changers.

I just went through the exercise of trashing 2 lakeshore 1/2 endmills, 2 collet tool holders and a spindle collet. I am hogging out the inside of an aluminum cover, and for both the tool holder pulled out of the spindle. They made an attempt to reach China ruining the part and putting a new drainage slot in the fixture.

I read the Tormach white paper and watched the NYCNC video on cleaning tools and lubing the R-8 collet. Subsequently I broke everything down, cleaned and carefully relubed where needed. When I got everything ready to run again I went to clean the tools still in the changer, I found that all of the shanks were coated with coolant residue. I cleaned them with a paper towel and acetone and the first test run went smooth, no issues.

How do you all deal with the coolant getting on the tools in the changer?


Ray

When I do a job on my PCNC 1100, I have learned a way to remove large amounts of material rather quickly.

I will create a hole pattern leaving .015 to .025 stock on the sides and bottom for finish on the part, then I will DRILL the appropriate size hole for the cutter I want to use, then I will plunge ruff the material out.

That puts all the cutting forces against the spindle instead of the side of the cutter and I get no cutter pull out

[m1carbine]

The cutter was lake shore 3 flute rougher/finisher variable flute end mill for aluminum

The depth of cut was .15, .1 step over, 35 ipm feed rate, 5140 rpm spindle speed.

It was a pocketing cut with helical entry with 50% entry feed rate.

I was not noticing any chatter, I had run this with a YG1 4 flute mill, but wanted to try the super duper lakeshore only have both trashed in their first cuts.

Ray

[handlewanker]

Hi, by adequate do you mean you just keep piling on the kilos until the tool stops falling out......LOL.....I don't think anyone can categorically state what pressure a drawbar needs to resist tool drop out......by experience, as you state, you arrive at a tension where the tools remain in the spindle against all cutter forces, provided the Bellville washers don't go soft on you or break down.
Ian.

[wtopace]

Guys - You are all respected members on this forum and you are all very "strong-willed" (for lack of a nicer term) people. Get over yourselves and try to help out the other member in need.

The cutter was lake shore 3 flute rougher/finisher variable flute end mill for aluminum

The depth of cut was .15, .1 step over, 35 ipm feed rate, 5140 rpm spindle speed.

It was a pocketing cut with helical entry with 50% entry feed rate.

I was not noticing any chatter, I had run this with a YG1 4 flute mill, but wanted to try the super duper lakeshore only have both trashed in their first cuts.

Ray

I don't see any immediate issues with those cut parameters. What is your entry angle? Perhaps it could be too aggressive causing the tool to bite in and pull out? I usually start with 2-5 degrees and increase from there.

[SCzEngrgGroup]

The cutter was lake shore 3 flute rougher/finisher variable flute end mill for aluminum

The depth of cut was .15, .1 step over, 35 ipm feed rate, 5140 rpm spindle speed.

It was a pocketing cut with helical entry with 50% entry feed rate.

I was not noticing any chatter, I had run this with a YG1 4 flute mill, but wanted to try the super duper lakeshore only have both trashed in their first cuts.

Ray

That's very surprising, as that's only about a 0.2HP cut. You should be able to do MUCH better.

Regards,
Ray L.

[Don Clement]

Hi, by adequate do you mean you just keep piling on the kilos until the tool stops falling out......LOL.....I don't think anyone can categorically state what pressure a drawbar needs to resist tool drop out......by experience, as you state, you arrive at a tension where the tools remain in the spindle against all cutter forces, provided the Bellville washers don't go soft on you or break down.
Ian.

Belleville washers are not truly compliant having parts which slide/rub against each other. My solution to the belleville washers breaking down on my Tormach PDB was to use a anti-seize compound on the belleville washer contacting surfaces.I used LP250 antiseize on the Tormach PDB belleville washers and no breakage has occurs since. LP-250 & LP-250F Anti-Seize Thread & Sealing Compound No pull out either. YMMV

[SCzEngrgGroup]

Hi, by adequate do you mean you just keep piling on the kilos until the tool stops falling out......LOL.....
......by experience, as you state, you arrive at a tension where the tools remain in the spindle against all cutter forces, provided the Bellville washers don't go soft on you or break down.
Ian.

So..... "piling on the kilos until the tool stops falling out" is bad, but "arriving ... by experience" at a tension where the tool stops falling out is good? Is there some difference between those two that I'm no seeing?

"By experience" you absolutely CAN "categorically state what pressure a drawbar needs to resist tool drop out". That is really the only way to arrive at a credible answer - by extensive testing and years of actual, real-world experience on many machines. How do you think Tormach arrived at the target drawbar tension number for their PDB?? If you dig up the old video they did shortly before the release of their PDB, you'll find they did precisely what you seem to find laughable, by "piling on the kilos until the tool stops falling out". They chose what they felt was a worst-case cut - IIRC, it was slotting, in a single pass, all the way through a 1" thick slab of 6061 with a roughing endmill. Hunt up the video, and see for yourself.

Regards,
Ray L.

[wendtmk]

Guys, if you don't keep the harassment of each other out of these posts, not only will the posts be deleted, but you will be banned from posting here. You all seem to have good insights, just knock off the personal attacks and stick to answering questions and giving information.

[popspipes]

My belleville's maybe arent as tight as an impact style PDB, but it operates a lot quieter, a bit quicker and doesnt wear the threads on the drawbar and collet.

There are advantages/disadvantages to both in my opinion, now if I could solve that 95 db compressor problem without having to move it outside ha!


My personal opinion of pullout is that the collet , spindle taper, toolholder shank, do not mate perfectly which results in a pinch point contact instead of gripping evenly along the shank, and even if it did mate perfectly, a slight diameter change in the shank size will reintroduce the problem.

I made flywheels and collets years ago for model engines, and to get a perfect fit, the flywheel taper had to be lapped to the collet taper for a given size shaft to get a perfect fit, once done the vibration had no loosening effect.

[m1carbine]

wtopace,

It is adaptive roughing waterline in Sprut, with axial plunge. There is no entry angle value that I can see.

Ray

[wtopace]

wtopace,

It is adaptive roughing waterline in Sprut, with axial plunge. There is no entry angle value that I can see.

Ray

Ah ha, I definitely would not recommend an axial plunge with a 1/2 endmill on a tormach, especially at those feeds (unless, of course, it is pre-drilled).

Try configuring your plunge with a spiral entry at a 5 degree angle, see my screenshot below. You might even work with the radius values to get a larger radius so your now doing a tight spiral downward.



Edit: I know this information is a little late, as your cutters are now in cutter heaven, but it's good rule of thumb for the future - never vertically plunge with an endmill unless you absolutely have to or you have a predrilled hole and can control the cutter engagement. Always use helical interpolation for pocketing.

[m1carbine]

wtopace,

I will give that a try next time. With adaptive, it does helical even with it set to plunge. Attached is a screen shot of the tool paths viewed from the side.

Ray

Attachment 292702

[SCzEngrgGroup]

My personal opinion of pullout is that the collet , spindle taper, toolholder shank, do not mate perfectly which results in a pinch point contact instead of gripping evenly along the shank, and even if it did mate perfectly, a slight diameter change in the shank size will reintroduce the problem.

I made flywheels and collets years ago for model engines, and to get a perfect fit, the flywheel taper had to be lapped to the collet taper for a given size shaft to get a perfect fit, once done the vibration had no loosening effect.

I'm not convinced that is a significant effect. And, if that were the case, then pull-out should be just as prevalent when using regular R8 collets to hold endmills. Yet, I've never had an endmill held directly in an R8 collet pullout. Again, it all comes down to how much tension you put in the drawbar, and years of experience has taught me that something in the neighborhood of 30 ft-lbs drawbar torque is the magic number than completely eliminates retention issues. The radial forces induced in the collet by the drawbar tension will significantly distort the collet, and improve the fit to both the spindle and the tool shank.

Also, as someone pointed out earlier, it is very rare to see pull-out in set-screw toolholders, which have, in effect, a point contact at the setscrew, and a line contact on the opposite side of the (rigid) toolholder bore. That is a far worse condition than a flexible, tapered collet and drawbar. An R8 collet, once tightened, will have, at a minimum, contact along three axial lines, which is a far better situation than that in a set-screw holder.

There are without question some dodgy collets, and toolholders, out there (ones from from China are always suspect, but even Tormach has had a handful of "dud" collets slip out the door - it's inevitable for any product that is not 100% QC'd), that would cause problems on any system, due to improper fit. That is something that should be checked for when having these problems. But I think those are quite rare, and the TTS system, in general, is no no more fussy about the collet or toolholder shank geometry than regular R8 collets, which certainly do not have a reputation for poor retention.

And, BTW - I've NEVER seen worn out threads on any drawbar, ever. It's usually the head, on the thrust face, that takes a beating, not the threads. Doubly so if the thrust washer is not kept well-lubricated, on BOTH sides, with anti-sieze. Recommended tightening torque for a 7/16-18 Grade 5 bolt (i.e. - a typical R8 drawbar) is 41 ft-lbs. So, at 30 ft-lbs, you'll never damage the threads, unless you run them bone dry for a loooooong time. Remeber, even Tormach considers both the drawbar and the collet to be "wear items", so you should expect to replace them every few years, which is an insignificant expense.

Regards,
Ray L.

[Don Clement]

There are advantages/disadvantages to both in my opinion, now if I could solve that 95 db compressor problem without having to move it outside ha!

My solution to compressor noise was to move the 80gal tank with compressor 20ft out into a 10 x12 Tuffshed. Also ran 220V and copper airlines underground.

[wtopace]

wtopace,

I will give that a try next time. With adaptive, it does helical even with it set to plunge. Attached is a screen shot of the tool paths viewed from the side.

Ray

Attachment 292702

Hmm, I believe the adaptive package is an extra cost add-on, correct? If so, I don't have have that and just normally configure my lead-in and lead-out manually (although the adaptive HSM toolpaths do look pretty awesome!). Your toolpaths don't look too bad there as far as helix angle.

If you want to email your Sprutcam file to me, I can take a look at it in the simulator and see if I can help any further. Shoot me a PM for my email address if you would like.

[wtopace]

Sorry double post

[SCzEngrgGroup]

wtopace,

I will give that a try next time. With adaptive, it does helical even with it set to plunge. Attached is a screen shot of the tool paths viewed from the side.

Ray

Attachment 292702

Are you using HSMXpress or HSMWorks? They will do a plunge entry on 2D Adaptive.... However, a helix, or ramp, puts much less stress on the tool and holder, so a straight plunge is more likely to induce pullout, not less.

Regards,
Ray L.