[PBMW]

2000 Haas Mini
Ran fine yesterday. Fire it up today, home it and get a tool fault. Do the toolchanger recovery, Tool will not release...you can hear the solinoid, but no joy...

[volthause]

Welcome to hell.

We had that same problem on 2 new VF-2s we have. For the first month we had them, neither one of them really cut any chips at all. They were constantly getting tools stuck in the spindle.

After going around in circles with Haas (they claimed it was our toolholders not being good enough first (they were and are), then that our pull studs were the fault because they weren't the Haas brand (even though they were more than comparable) they finally concluded that it was the umbrellas style tool changer that was the culprit. They replaced both with the vertical style and it's been smooth sailing ever since.

I still have no idea why.

[artin51]

I've had this happen a few times after heavy cutting. Does the carousel go towards the tool and the tool just doesn't realease? If that's the case, while the carousel is in postion to pick up the tool, give a couple of shots with a rubber mallet to the other side of the tool holder while the solenoid is open. Usually works for me....

[PBMW]

Finally figured that "What the heck...it's a Haas" Used a pry bar and out she came.

[Geof]

Pry bar, rubber mallet, aluminum drift with a big hammer; used them all.

We did discover some toolholders would stick more than others so we stopped using them for prolonged heavy cutting.

On our VF0 we had really bad sticking until we put an air reserve tank downstream of the regulator; this reduced the pressure drop when the tool eject cylinder operated and sticking became very rare on that machine.

[PBMW]

This machine has been actually quite reliable. Sometimes the toolchanges are a little noisy, I spray a little WD40 up in the spindle and work the tool release button and that cures it for a while. Wasn't doing anything heavy. It's a Minimill fer Gawds sake. I think the cycle time was about a minute for that tool. Face and a bore gets interpolated, Might be a min anda half total cycle time. This machine is running secondary to my Akira Seiki so it sits untill the part change and deburr happens on the other machine...Prolly 5 min down time between cycles. My point is that there was little load to generate heat in the spindle. Strange if ya ask me...

[Geof]

Forgot to mention we also try to remember to wash out the spindle taper and the tool holders with methanol to remove coolant residues. This does make a difference because the residue can be very sticky.

You can also get problems with a sticky solenoid valve. If the air does not turn on quickly the eject cylinder moves slowly and does not develop enough impact to knock the tool out. I had this problem on a SuperMini in my home shop that did not have good clean dry air. Pouring methanol down the airline solved that one, followed by rigging up a trap for moisture.

[dertsap]

if the stud is a little too tight the taper will swell , some people believe it most don t but ive seen the difference many times over with 50 tapers , all the machines at the last company had a different stud so we were always swapping studs in and out of those holders , two machines in particular were sensitive to this , anytime a tool stuck a few times then i would retighten the stud , 8 out of 10 times that would solve the problem .

under normal circumstances the studs should only be snugged up and lock-tited

[Vern Smith]

For what it's worth my local Haas operator told me to spray dry lube on the tool holders. He also recommended putting a swab on a stick up the spindle taper to clean any grease accumulations from the draw bar clamp.

Despite all this mine still stick after heavy cuts and make a hell of a clunk when they leave the spindle. I guess I'd better talk to Geof about the air tank.

Vern

[mc-motorsports]

[QUOTE=Geof;489558] If the air does not turn on quickly the eject cylinder moves slowly and does not develop enough impact to knock the tool out. QUOTE]

+1

The CAT 40 drawbar smacks the back of the retention knob. The clamp/unclamp piston has to build enough pressure to overcome the springs on the drawbar, plus accelerate the drawbar to give it that "umph" so it will actually impact the tool out of the tool taper.

And yea, after extended use especially during heavy cutting, the tool will tend to suck up in the taper a little more, makes it easier if the spindle gets hot. Then the tools are a little harder to eject, it's known issues with CAT and BT tooling.

MC

[Geof]

....Despite all this mine still stick after heavy cuts and make a hell of a clunk when they leave the spindle. I guess I'd better talk to Geof about the air tank.

Vern

I will preempt you.

Get an airtank with a capacity of a cubic foot or two.

Take the airline of the outlet of the regulator and install a tee fitting.

Reconnect the airline to one end of the tee and connect the tank to the other.

Use large diameter fittings and large diameter hose.

With this modification you should hear a distinctly more solid 'clunk' when the solenoid opens and the release piston operates.

[PhillipM]

We had the exactly the same problem with our VF4 - running it at 7500rpm for a couple of minutes @ 2500mm/m doing some ally work - tool got stuck, wasn't the specific holder as 2 other tools did the same, it must be spindle heat causing a shrink-fit as after limiting all the tools to 7000rpm max we've had no problems.

Well, bar being missing 500rpm-worth of extra MRR in ally, which we weren't too happy about...

[Vern Smith]

Geof,

The most bang for the buck seem to be the garden variety 125 psi 5 gallon jobs to fill your tires with. I think that would come in around 1.5 cubic feet. I might have to weld an over-sized bung into it to get the large feed lines you are referring to. Sounds like an easy install.

Thanks for the tip, after my recent tool non unclamp disaster I hold my breath at every tool change.

Vern

[Geof]

...The most bang for the buck seem to be the garden variety 125 psi 5 gallon jobs to fill your tires with. I think that would come in around 1.5 cubic feet. [B]I might have to weld an over-sized bung into it.....

Vern

You really are planning on getting a bang for your buck welding on a pressure vessel; I do n ot have the nerve for that.

Fortunately the 'bung hole' on one of these tanks is 1/2"NPT which is plenty big enough for a 1/2"NPT by 3/4" hose nipple. Actually it doesn't natter too much if the fittings are smaller than the hose, a short constriction does not have much influence. And almost anything will be larger than the ports inside the regulator which are what restricts the flow.

[Vern Smith]

OK, I'll epoxy it.

[cnc-king]

2000 Haas Mini
Ran fine yesterday. Fire it up today, home it and get a tool fault. Do the toolchanger recovery, Tool will not release...you can hear the solinoid, but no joy...

one of the main problems for tool to stick in the spindle regardless of machine brand is moisture in the air line we had the same problem and installed an air dryer and never had that problem since. it happens more in the summer time because of the high humidity - my 2 cents

[Mr.Xtreme]

Hey Guy's
We have a VF2 Super Speed and after a couple of weeks does the same thing.
A Really good Haas Tech said to keep the Spindle nose inside clean, and lube a couple of holders at the retension knob area with white liteium grease (same grease as used on car door hinges). It smooths it right out. Even really heavy cuts in SS does not stick any more.
If the tool needed to be pried out I would look at quite possibly the Spring Pack (bevel washers) that there is failure there.

[automizer]

2000 Haas Mini
Ran fine yesterday. Fire it up today, home it and get a tool fault.

One thing you may want to get in the habit of is to empty out the spindle at the end of the day. At work we had problems on a VF2 that the tools would often stick first thing in the morning. Try going to an empty pocket as part of your shut down. Helps a lot

[bloefeld]

I agree that dry air is a big issue, put a desiccant dryer in-line if you work with high humidity.

I have doubts about the heat issue, the coefficient of thermal expansion of the two parts are very close and it seems unlikely to me that there will be that much more heat that far up the taper to actually get it to freeze.

I would try putting about 20 - 40 psi more on-line and see if that doesn't give it a more satisfying thump. Nothing will get hurt because everything pneumatic has a 3 to 5 times safety factor.

I keep everything nice and clean. In addition to Geof's alcohol, I would also try a citric degrease, they are better on water borne coolants.

I give everything a very thin coating of moly grease but clean out the spindle everyday.

Cheers,

Bloefeld

[Geof]

....I have doubts about the heat issue, the coefficient of thermal expansion of the two parts are very close and it seems unlikely to me that there will be that much more heat that far up the taper to actually get it to freeze.... Bloefeld

Temperature can have an effect. At my place we used to leave a tool in the spindle to prevent chips getting blown in, and when machines were not needed we would still do the Warm Up program. After sitting for three days the spindle would generally get quite warm from the Warm Up, and we discovered that on the following day the tool would be stuck in the spindle when the machine was turned on and homed. The only conclusion we could draw was that the tool had somehow snugged in tighter when the spindle got warm.