VMC ... tool will not release from spindle bore - Page 2
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  1. #21
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    If you have access to the screws holding the unclamping cylinder down, undo the screws/nuts by about 1/4” and put a piece of aluminium in the gap between the piston and the drawbar (aim for a snug fit with the packing) and then tighten the screws/nuts down again to see if the tool will come out or get loose.

  2. #22
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    Quote Originally Posted by jancollc View Post
    I've also had best success with the brass hammer to the side of the flange, but I've never dealt with one that was stuck this bad.

    Might try running the spindle warm-up program, or just let it go wide open for a while- heating up the spindle may help.
    Yup, I'd run a warmup prog then run it flat out for 45 mins and see if that makes a difference

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    Even though I think low oil is the biggest problem, I'd still like to add:

    1.) Do not hit the holder with a hammer or object of any kind. Hit the holder, hit the super precision bearings. Impossible to do one without the other feeling it too.

    2) Unless the pry bar touches ONLY the tool flange and the rotating part of the spindle face, the pry bar is bad too, but in some extreme cases may be your only hope. Another idea? If possible, use wedges between the tool flange and the spindle face, just like the ones you'd use to remove a chuck off a Jacobs taper but bigger. No amount of pressure created by the wedges can be transmitted to the bearings or anything else but the tool holder and the tool socket. Sadly you'll still have to do some tappy-tap-tap on the wedges, but I'm thinking less of that force is directed into the bearings then wacks to the tool holder.

    3) If these fail, yes run it and heat it up, a lot. Then try again. Maybe even spray some cooling spray like used to test electronics up into the tool holder right before trying.

    Dave

  4. #24
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    Quote Originally Posted by Delw View Post
    Sounds like your drawbar isnt pushing down enough 3/8 wont cut it. I believe most are around 3/4 to an inch of travel.
    If the “pneumatic boost cylinder” on top means this is an air over hydraulic setup, I think I know what the problem is.

    I thought it curious the little oil reservoir connected to the boost cylinder was almost empty.... but when refilled, it drained back to empty after just 20 or so cycles...suspect seal failure / oil leak in the lower cylinder that does the drawbar push down. The puddle of oil on top of the hydraulic "pancake" I thought came from spillage when refilling the resevoir but now think mostly from leakage.

    img_1307.jpg

    Above from the parts book, showing the setup. Some of the lines shown may have to do with TSC.

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    Quote Originally Posted by Milacron View Post
    If the “pneumatic boost cylinder” on top means this is an air over hydraulic setup, I think I know what the problem is.

    I thought it curious the little oil reservoir connected to the boost cylinder was almost empty.... but when refilled, it drained back to empty after just 20 or so cycles...suspect seal failure / oil leak in the lower cylinder that does the drawbar push down. The puddle of oil on top of the hydraulic "pancake" I thought came from spillage when refilling the resevoir but now think mostly from leakage.

    img_1307.jpg

    Above from the parts book, showing the setup. Some of the lines shown may have to do with TSC.
    more than likely time for orings/seals. it must be really bad if you cant get it to even budge the tool. They all should be avail everywhere, mcmaster carr will probably have them as well.

    only other way I can think of and I did it with my supermax. was to take the unit off make a u shapped brace bolt it to the head and use a prybar and push down on the drawbar to release the tool.
    I had to make a bushing to hit the draw bar to to clearance issues I think it was a tad over one inch as it had to clear the pulley i.d..

  6. #26
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    Well, it sounds like you may be onto the root problem.

    If you get the leak repaired and/or release as suggested manually and it still doesn't move-- I wonder if the combination of dry ice/ice on the tool and a simple electric heat gun or 2 on the spindle would yield enough differential to enable tool holder release. I'm thinking heat gun would not kill bearings-- thoughts?

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    Before you tear into the release cylinder just to see IF the tool will move in the taper. At the very most a 40 taper will put 2K pounds of retention force into the tool and it is easy to get that with a cheater bar. Don't try to pull the tool out, just make sure that it moves in and out of the taper a couple of thou. My guess is someone let the spindle get hot and left a tool in it and now it is really stuck in there.

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    Took the hydraulic cylinder apart today...smoking gun...all three cup seals were toast....rough surfaces, no lips, and fell apart during removal. Curious this would happen on such a newish (2011) VMC with low hours. Manuf. is Valqua...wonder if they had a run of bad material back in 2010 ?

    I was able to get the part numbers with some diligent microscope work on the remants.

    UHS 75, UHS 70 and DH 70 (1 each)

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    Well, one thing I do is take an aerosol can of Graphite, and coat the worst offending holder.
    Yes, this is bound to change your offset.. but not much.
    I have troubles mostly on tools that are run hard, with higher loading... and it is my belief that every time they vibrate, they seat in just a bit more.
    Anyhow, I tried scuffing up a couple holders with fine emery cloth... I just didn't like the idea.
    Then I tried aerosol dry moly lube...
    but for some reason, the graphite spray seems to work a bit better.

    Old beat up holders usually do not present a problem, I notice this most frequently on my newer high-quality holders where the holder and spindle are near perfectly in full contact.
    Other than that.. ts spread about in the tool-changes, but so thinly it generally won't be a consideration.
    I re-apply based on experience.

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    Quote Originally Posted by Milacron View Post
    Took the hydraulic cylinder apart today...smoking gun...all three cup seals were toast....rough surfaces, no lips, and fell apart during removal. Curious this would happen on such a newish (2011) VMC with low hours. Manuf. is Valqua...wonder if they had a run of bad material back in 2010 ?

    I was able to get the part numbers with some diligent microscope work on the remants.

    UHS 75, UHS 70 and DH 70 (1 each)
    I don't believe that is the problem in my case.
    I notice time when some holder come blasting out of the spindle like a bullet... they were trying to stick, but were overcome by sheer force.
    But, I will bear in mind this possibility as well, although my machine is a bit newer.

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    Quote Originally Posted by Milacron View Post
    Took the hydraulic cylinder apart today...smoking gun...all three cup seals were toast....rough surfaces, no lips, and fell apart during removal. Curious this would happen on such a newish (2011) VMC with low hours. Manuf. is Valqua...wonder if they had a run of bad material back in 2010 ?
    Very unusual IMO. Any sense of what the cup seals are made of? Polyurethane is pretty common and is compatible with most oils. Not so good with many common solvents. Wonder if there was some cleaning or mixing of something in the oil that degraded the seals.

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    Some polyurethanes don't age all that well, add in a error on mix ratios on manufacture and they can literally fall apart in a few years use or storage. Got right the material can almost be bullet proof too! But slight errors and it becomes something akin to hard cheese in time.

  14. #33
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    Quote Originally Posted by Vancbiker View Post
    Very unusual IMO. Any sense of what the cup seals are made of? Polyurethane is pretty common and is compatible with most oils. Not so good with many common solvents. Wonder if there was some cleaning or mixing of something in the oil that degraded the seals.
    I do seem to have a knack for getting machines with strange problems that no one else has. OTOH, I have another Litz CV-1000 VMC made in 2007 with twice the hours and has what appears to be an identical drawbar system... and it works fine.

    Hydraulic U Seal UHS 70 X 80 X 6 - Eezee Pte LtdEezee Pte Ltd


    One thing for sure, I want to avoid Valqua for the replacements ! FWIW these are green in color, if that means anything.

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    My local seal guy sold out to H&D Distributors last year. I think they have stores nationwide. Prices are higher than what my guy charged me, but they do have stuff on hand and seem to be pretty knowledgable.

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    That was it... replaced the seals today, put it all back together, and after priming the cylinder with hydro fluid she works like a champ... tool pops right out...zero corrosion on taper..,problem was 100 percent with the push cylinder.


    Below is pix of the 3 seals I replaced

    01ca3c08-b000-4147-add9-04a0b4b9bb6e.jpg

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    Glad to see you got it sorted quickly has to be a load off your mind.

    Charles

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    Btw, further mystery is this saga is that not only did the original seals become so brittle as to fall apart, but there is "crud" on the two seals that were the most brittle.... to the extent I had to carefully clean some areas just to see the part numbers. And yet the remaining hydraulic fluid looked clear/normal enough.. and no crud anywhere in the cylinders, only on the two seals. All I can figure is the crud was somehow from the seal material itself.... but to turn black and brown like that...strange...

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    Quote Originally Posted by Milacron View Post
    ...All I can figure is the crud was somehow from the seal material itself.... but to turn black and brown like that...strange...
    Some synthetic oils will attack seals and o-rings. Something you have to be aware of in air- syn oil in the compressor can make it into the lines and attack seals downstream.

    Possible they used some assembly lube that didn't play nice with the seal material.


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