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Parlec collet chuck issues.

T Bigelow

Plastic
Joined
Mar 29, 2011
Location
Long Island, NY, USA
I am currently using parlec c40-20er412 collet chucks with their "power nut" and pull studs for a Haas cat40 spindle. I am new to cnc manufacturing, this is my first experience with cat tooling and ER type collets as such I'm having a few issues with tool T.I.R and collet disassembly.

When I assemble a tool in the collet chuck I am using a norbar 200th torque wrench purchased from techniks to tighten the collet nut and pullstud to approx. 85% of parlec max spec. Depending on the day I get anywhere from .0002 to .0008 T.I.R., once I even had .0015 T.I.R. If I torque the pullstud and put just the tool holder in the spindle I get max .0002 T.I.R. Thus it seems to be how the collets are seating in the holders.

To compound my problems when I go to disassemble the holder the collets seem to stick in the taper, to the point where I have to stick a drift pin through the holder and tap lightly on the back of the tool as I loosen the collet nut. The reason for doing this is to avoid distorting the collet, I have damaged a few collets and even destroyed a powernut because of this problem.

Seeing how I am new to cnc I'm not ruling out anything, especially human error.

Main question, has anybody run into these issues before?
Anyone have problems in the past with parlec tooling or norbar torque wrenches?

Any input would be appreciated.
Thanks,
Tom
 

MattW

Hot Rolled
Joined
Sep 10, 2004
Location
Fairfield, PA, USA
On the topic of collet extraction, the collet nut should have an internal clip ring that engages the groove in the collet. When you loosen the nut, and then back it off a little more, it should extract the collet from the taper. When assembling the setup, I've had to insert the collet, and tighten the nut until the clip engages the groove, then back the nut off, and THEN insert my end mill.

Now I don't know the Parlec hardware specifics, but that is how my ER holders work.

For your TIR, mark the holder and collet at the point of highest runout and experiment with rotating the holder in the spindle, and the collet in the holder. That may help you isolate the source of the runout.
 

emt2688

Cast Iron
Joined
Mar 6, 2006
Location
NE Nebaska
As you are new to CNC manufacturing, just would like to point out that the ER collet must be inserted into the collet nut by clicking it in place. Some newbies insert the collet into the chuck and then spin the nut into place. This is a no-no. The collet must seat into the nose of the nut first.

Your having to drive the collet out of the chuck sounds like an assembly problem outlined above.

Pat
 

Brian

Stainless
Joined
Jul 20, 2002
Location
Phoenix, AZ USA
As Pat said, you are installing the collets incorrectly in the nut. They have to be "tipped" into place in the nut, so the collet snaps under the eccentric snap ring. Then you can slide it into the holder (I usually insert the shank of whatever tool I'm using to make sure the collet doesn't come out) and then spin the collet nut tight.

If you do all of that correctly, you shouldn't see more than about .0005" (worst case) runout unless you are using cheap Chinese collets and tool holders.
 

cncbrit

Hot Rolled
Joined
Apr 6, 2011
Location
California
Yeah put everything together, slight finger tight, make sure the cutter shank still rotates in the assembly, and feels like the perfect dowel pin fit, snug it up finger tight, and check that the tool is now firm, then add a wrench to it, I just make it good and tight with the wrench, never had a problem.
 

emt2688

Cast Iron
Joined
Mar 6, 2006
Location
NE Nebaska
Yep, I'm a noob alright. Thanks for the instruction, and T Big, sorry for the bad info.

Sorry Matt, I was actually referring that to T Big, as he stated in his first paragraph that he was new to CNC manufacturing.

I didn't take your advice as bad info.
 

T Bigelow

Plastic
Joined
Mar 29, 2011
Location
Long Island, NY, USA
Thank you for the input thus far. I am aware that the collet has to be properly "snapped" into the collet nut before screwing it into the tool holder. That lip in the nut is also what is distorting the collet during disassembly. It puts a deep gouge in the collet if you use the wrench to "pop" the collet out. I even had one collet nut where the lip broke off after destroying the collet. As I previously stated, these are all parlec parts I am dealing with.

The way I figure it I'm either doing something aside from the obvious wrong, the parlec tooling is crap, or my torque wrench is far from accurate.
Is there any way to verify the torque measurements on my wrench?

Thanks,
Tom
 

Dave K

Diamond
Joined
Mar 21, 2004
Location
Waukesha, WI
I don't mean this to be insulting, but the only time I've had issues like this was when I tried to squeeze a collet down far enough to hold a tool that was about .012 under the nominal size of the collet.

I assume you're not doing that?

I always thought parlec was pretty decent, maybe I'm wrong, or you got some bad ones?
 

Brian

Stainless
Joined
Jul 20, 2002
Location
Phoenix, AZ USA
ER Collets have a range of 1mm (.040") so squeezing them down is normal.... granted a 1/2" imperial ER collet will hold a 1/2" shank more securely and with less run out than a 13-12mm collet will, but they are still made to have a range.

I was just working earlier this week with a friends new to him CNC, and he had acquired a couple of Jacobs ER25 holders, brand new. Now the collets we had are Chinese, and they would not engage in the Jacobs nuts correctly, the snap ring was wider (groove could have been narrower) or placed too far back from the nose and wouldn't let the shank of the tool into the collet when snapped into the nut. Traded one of the Chinese nuts for the Jacobs nut and all worked correctly.

So, evidently there are variances in some of these holders, collets and nuts.... get the wrong combination and you will have problems. I know all of my ER25 stuff is from Techniks and collets are either Kennametal, Rigofix or Techniks and I haven't ever run into issues.
 

Dave K

Diamond
Joined
Mar 21, 2004
Location
Waukesha, WI
ER Collets have a range of 1mm (.040") so squeezing them down is normal....

That is what the manufacturers claim, but not always the case. I've run into the exact same problems that's being described here by clamping smaller items that supposedly still fit the range. And, sometimes not. Like you said, it depends on manufacturers specs.
 

Dan from Oakland

Titanium
Joined
Sep 15, 2005
Location
Oakland, CA
How tight are you tightening the collet nut? You may be overtightening it, and distorting the nose. If you are having problems with the collet sticking, that may be the cause.
Dan
 

gregormarwick

Diamond
Joined
Feb 7, 2007
Location
Aberdeen, UK
That is what the manufacturers claim, but not always the case. I've run into the exact same problems that's being described here by clamping smaller items that supposedly still fit the range. And, sometimes not. Like you said, it depends on manufacturers specs.

Totally agree, unless I'm totally stuck I NEVER clamp below nominal size in an ER. Reduced shank contact aside, they just don't like coming out again because they've collapsed so far that the lip is barely in the groove.

One thing I haven't seen anyone mention is that somewhere in the fine print most er collet manufacturers tell you to oil the taper (only the taper) during assembly to ensure even pull down in the taper and maximum clamping force on the tool. I use aerosol silicon oil and have never had much trouble.

Gregor
 

AlfaGTA

Diamond
Joined
Dec 13, 2002
Location
Benicia California USA
I am with Dan above....
You say that you are using a torque wrench....unless the drive of the wrench is on center with the nut the applied torque value will be different.
So if your tightening tooling uses a "crows foot" or other offset socket setup the value set to the wrench will not be the same on the tool...

I gauge using the makers collet wrench and tightening firmly by hand.
Cheers Ross
 

scudzuki

Stainless
Joined
Aug 6, 2008
Location
SouthEastern Pennsylvania
I am with Dan above....
You say that you are using a torque wrench....unless the drive of the wrench is on center with the nut the applied torque value will be different.
So if your tightening tooling uses a "crows foot" or other offset socket setup the value set to the wrench will not be the same on the tool...

I gauge using the makers collet wrench and tightening firmly by hand.
Cheers Ross

If the crow's foot wrench is at 90 degrees to the torque wrench it will be very close, within a few percent.

Joe
 

Dave K

Diamond
Joined
Mar 21, 2004
Location
Waukesha, WI
Does everyone use a torque wrench to tighten their collet nuts to spec. or do you just gauge it by feel?

-Tom


I go by feel. I didn't even know there was a torque recommendation.

By the way, as a side note, to help combat the problem of chucking something smaller than nominal size of an er collet, Mari-tools has them in 1/64 increments. Thank you soooooo much for that!!:Ithankyou:
 

PaulT

Stainless
Joined
Mar 4, 2002
Location
Brisbane, CA, USA
I go by feel. I didn't even know there was a torque recommendation.

ER collets take more torque than you realize to get full gripping capability.

On ER32 collets most manufacturers recommend between 65 and 85 ft-lbs.

I discovered the hard way that if you are using carbide endmills and you don't torque them up to this range that you can have problems with the endmills pulling out and slipping. I also clean any oil off the endmill shank and collet grip surface with lacquer thinner.

Even 65 ft-lbs is a pretty hard pull on the typical ER32 collet wrenches that are sold, they should make them a little longer (or maybe I'm getting old).

Paul T.
Power Technology
 

chipload007

Banned
Joined
Feb 25, 2010
Location
Georgia
First of all, there are only a handful of companies in the world that manufacture ER collets. Even if you buy it from Parlec, or Kennametal, or Sandvik, etc. the collet is probably from India or Taiwan. The only ER system I know of that guarantees run-out is BIG Daishowa, sold in the US through BIG Kaiser. They make their own ER collets, collet chucks, and collet nuts. They guarantee less than 0.00012" T.I.R. at 5 times diameter. You can probably just buy one of their collets and put it in the Parlec holder and reduce the run-out to around 0.0005".
 








 
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