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  1. #1
    Join Date
    Mar 2007
    Posts
    89

    XY out of square!!!

    Gentlemen,
    Last Saturday I discovered a major out of square condition on my Haas VF10.
    I explained it in another thread but I thought a separate thread would be appropriate. Here is a copy of the post in the other thread.

    Hi,
    I just discovered an out of square condition on my three Haas mills. I have a VR11, a VF10 and a VF6. All three are out of square between X and Y. Inspection found an out of square hole pattern on a large plate machined on the VF10.
    The VF10 was .340 in 120 inches.
    The VR11 is .052 out of square in 120 inches.
    The VF6 is .007 out of square in 60 inches.
    The VF10 X axis linear guides were recently (within a year) replaced by Haas. The linear guide replacement was NOT the cause of the out of square condition. The linear guide replacement was a simple task and is difficult to get wrong because of the design.
    A square artifact would allow an accurate check of squareness - the larger the better. To check squareness align one leg of the square with either the X or Y and check the other leg for runout. My solution was to set up a laser tracker to check and adjust the squareness.
    The adjustment procedure is simple.
    Set up whatever inspection device (square or tracker)
    Pull back all of the XY way covers.
    Loosen the linear guide trucks carrying the saddle (Y axis).
    Push/pry the X axis square.
    Tighten the trucks.
    We also loosened the Y axis ball nut to allow repositioning along the axis of the ball screw.
    We now have the VF10 X axis square with .002 in 120 inches.
    Now we will address the VR11 and VF6.

  2. #2
    Join Date
    May 2010
    Posts
    34

    Re: XY out of square!!!

    I just bought a Haas OM2 and found it is also out of square (Y is 0.0016 in/in). How long do you think it would to have a technician fix this?

  3. #3
    Join Date
    Mar 2007
    Posts
    89

    Re: XY out of square!!!

    Don't think of it as Y is out of square with X. Think of it as X is out of square with Y. The Y is not adjustable. You can do this without a technician. Follow the procedure outlined in the first post.

    Align your square device with the Y axis - then adjust the X to be square with Y.
    This is a pretty simple process. The trucks carrying the saddle along the Y axis are reachable.

  4. #4
    Join Date
    Mar 2010
    Posts
    1852

    Re: XY out of square!!!

    I sure hope that the machine was perfectly leveled before you went to all that effort!

    Mike
    Two Haas VF-2's, Haas HA5C, Haas HRT-9, Hardinge CHNC 1, Bother HS-300 Wire EDM, BobCAD V23, BobCAD V28

  5. #5
    Join Date
    Mar 2007
    Posts
    89

    Re: XY out of square!!!

    Thanks for bringing up the first thing to check when you find a machine not positioning correctly. I forgot to mention it.
    When a problem presents itself "level" should almost always be the first thing checked.

    All of what effort? The squareness correction was simple and needed only an hour or so and was very easy.

    To address your perfectly level concerns.
    All three machines sit on individual concrete pads.
    The pads were poured just for the three machines.
    The pads are three foot thick - rebar reinforced.
    The shop has precision levels.

    Let's define "level".
    If "level" as most people think of it was as important as most people think it is then a slant bed lathe would not be square or "orthogonal".
    With a machine mounted on a base - whether the base was originally part of the machine or not - then you can square the machine and expect it to remain physically 'orthogonal'.
    This was our attempt in our shop. And yes, the machines are sitting on levelling screws and pulled down with clamps to the levelling screws.

    We have precision levels to get the machine close to level but we do not rely on 'level' to claim the machine is square.
    We have a laser tracker to determine the actual 'orthogonality' and to verify our corrections.
    There is a point of diminishing returns and we do not expect perfection. We adjust our machines to make parts in tolerance.
    We determine which corrections to apply.
    We have a five axis machine that the moving components move straight/round as expected but the machine components are not orthogonal (square to each other).
    We put a control on the machine and wrote a kinematics module to use data collected by the laser tracker to adjust the slide positions to correct the orthogonality using the control.
    This was much easier and cheaper than disassembling the machine to correct for the machine being mechanically not orthogonal.

    Have you ever used a laser to do ball screw calibration on a machine?
    Have you watched the ball screw grow by .0004/.0005 per each back and forth cycle on a 60 inch travel X machine?
    I have.
    The X ball screw in this machine grew by over .004 inch before the growth slowed. It would have continued to grow I don't know how much but I learned not to trust the machine positioning for precision work until the machine is warmed up a little bit. We corrected the ball screw in the as warmed up condition. We were able to obtain acceptable positioning and repeatability.

    Have a good day
    thanks
    Stuart

  6. #6
    Join Date
    May 2010
    Posts
    34

    Re: XY out of square!!!

    I've been making some progress. This is only a hobby for four me so it moves slow. I removed the covers and cleaned out all the plastic chips that made their way in there. I found gobs of red grease around the z axis but none around the X or Y. I'm not sure where I make the adjustment. Do I just loosen the cap screws on the Y axis bearing blocks and bump it into place?

    My manual says it is not necessary to level the machine. I did it with a little carpenters level and don't have anything better. I might borrow a better one if I can but I didn't think leveling was something you needed to do with small machines. The haas mini mill I had before was never properly leveled and it never gave me these problems.



    Attachment 236388

    Attachment 236390





    Attachment 236382


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  7. #7
    Join Date
    Mar 2007
    Posts
    89

    Re: XY out of square!!!

    I think the answer is yes.

    Loosen the Y axis blocks under the saddle that runs on the Y axis guides. This will allow you to adjust the X axis so it is square with the Y axis.
    That machine looks like it should have 4 blocks to loosen.
    I would loosen all the cap screws.
    Adjust the X axis square.
    Snug the caps screws.
    Check the X axis for square.
    Tighten the caps screws a little bit.
    Check the X axis for square.
    Finish tighten the cap screws.
    Check the X axis for square.

  8. #8
    Join Date
    Mar 2010
    Posts
    1852

    Re: XY out of square!!!

    Me thinks you have started a landslide which will have disastrous outcomes.
    Two Haas VF-2's, Haas HA5C, Haas HRT-9, Hardinge CHNC 1, Bother HS-300 Wire EDM, BobCAD V23, BobCAD V28

  9. #9
    Join Date
    Mar 2007
    Posts
    89

    Re: XY out of square!!!

    Not sure why you would think this way.
    We have done this on our three Haas mills (VR11, VF10, VF6) and have been VERY pleased with the results.
    As far as I know, we have only done it once to each machine.
    We have seen no negative results from this adjustment. If fact only positive.
    There is nothing magic about machine tools. They adjust like any other mechanical device.
    You just want to be careful and think through what you want to attempt.
    Nothing I have done is just spur of the moment action. I have always watched the a fix for a while to see if that was really a fix.

  10. #10
    Join Date
    Feb 2009
    Posts
    6028

    Re: XY out of square!!!

    I will put my .2$ in. Level means nothing, close is good enough. Now twist and bow is critical, and a lot of machines are very sensitive to point loading on a leveling foot. Quite easy to induce twist or bow with incorrect adjustments.

  11. #11
    Join Date
    Mar 2007
    Posts
    89

    Re: XY out of square!!!

    underthetire - I will agree.
    About the only reason to worry about level is to get the coolant to drain in the correct direction.

  12. #12
    Join Date
    Mar 2010
    Posts
    1852

    Re: XY out of square!!!

    Quote Originally Posted by stustev View Post
    Not sure why you would think this way.
    We have done this on our three Haas mills (VR11, VF10, VF6) and have been VERY pleased with the results.
    As far as I know, we have only done it once to each machine.
    We have seen no negative results from this adjustment. If fact only positive.
    There is nothing magic about machine tools. They adjust like any other mechanical device.
    You just want to be careful and think through what you want to attempt.
    Nothing I have done is just spur of the moment action. I have always watched the a fix for a while to see if that was really a fix.
    Just suggesting that you are talking to a, most likely inexperienced, person who only has a carpenters level and probably no laser tracker such as you do and encouraging him to make modifications to his machine. How is he measuring in the first place?

    Mike
    Two Haas VF-2's, Haas HA5C, Haas HRT-9, Hardinge CHNC 1, Bother HS-300 Wire EDM, BobCAD V23, BobCAD V28

  13. #13
    Join Date
    Mar 2010
    Posts
    1852

    Re: XY out of square!!!

    The reason the larger machines are leveled is that they were leveled to remove casting twist before aligning the axis's in the first place. On larger machines it is important to level and remove twist before adjusting rails. Not necessary on a mini though. Why would you want to adjust the rails on a mill that has a casting that is slightly twisted?

    It is similar to a lathe where you have taper in a turned shaft. You don't move the rails, you adjust by tweaking the level from one end to the other since many heads are fixed in place on small lathes. Done it many times to get a lathe trued.

    Mike
    Two Haas VF-2's, Haas HA5C, Haas HRT-9, Hardinge CHNC 1, Bother HS-300 Wire EDM, BobCAD V23, BobCAD V28

  14. #14
    Join Date
    Mar 2007
    Posts
    89

    Re: XY out of square!!!

    Quote Originally Posted by Machineit View Post
    Just suggesting that you are talking to a, most likely inexperienced, person who only has a carpenters level and probably no laser tracker such as you do and encouraging him to make modifications to his machine. How is he measuring in the first place?

    Mike
    good point - I did assume the asker is competent to do the adjustments I suggested.
    On that vein

    Hyrum - how did you determine the machine guides are out of square?
    What do you have to determine when the guides are square to one another?

    thanks
    Stuart

  15. #15
    Join Date
    May 2010
    Posts
    34

    Re: XY out of square!!!

    I first noticed it was out of square while testing the renishaw probe on my fixture plate. I confirmed it with a 123 block and a test dial mounted in the spindle.
    I do not own a laser but could get a granite square for a few hundred bucks.

    Attachment 236438
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    Attachment 236444

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  16. #16
    Join Date
    Feb 2009
    Posts
    6028

    Re: XY out of square!!!

    If you could get a calibration square for a few hundred, get it! I think the last 18x18x4 was ~$3k i bought

  17. #17
    Join Date
    May 2010
    Posts
    34

    Re: XY out of square!!!

    I'm sure your square is very nice.

    shars.com - 15quot x 10quot x 15quot Precision Granite Square

    This should work for what I'm doing. The travel on my machine is only 12"

  18. #18
    Join Date
    May 2010
    Posts
    34

    Re: XY out of square!!!

    Something interesting I found in the service manual; it says you should check for squareness after every crash. I think it is clear my machine was either crashed hard or dropped at some point in time. Since finding the XY is out of square I've also checked and found the ZY and ZX is out. It seems like the ZY could be adjusted the same way you described but on the z blocks. But the the ZX does not look easy. Shims under the column? The muck keeps getting deeper with this problem.



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  19. #19
    Join Date
    Mar 2007
    Posts
    89

    Re: XY out of square!!!

    Quote Originally Posted by Hyrum View Post
    Something interesting I found in the service manual; it says you should check for squareness after every crash. I think it is clear my machine was either crashed hard or dropped at some point in time. Since finding the XY is out of square I've also checked and found the ZY and ZX is out. It seems like the ZY could be adjusted the same way you described but on the z blocks. But the the ZX does not look easy. Shims under the column? The muck keeps getting deeper with this problem.



    Sent from my SPH-L720 using Tapatalk
    How far out are each?
    I think a 6 inch machinst square would work very nicely for your machine.
    An ajustment of the Z blocks will not affect motion but will affect the tool axis squareness.
    The column will need to be 'adjusted' to square the motion.
    The rabbit hole gets deeper and deeper. When evaluating a machine tool there are a LOT of issues to check.
    My guess is the machine was assembled much like you see it. With a small machine this condition would hardly ever be found.
    Hopefully, you will only need knee high rubber boots to wade through the muck.
    On my 5 axis Cinci the head is an AB head so I did not need to worry about the mechanical tool axis adjustment.
    I dialed the tool axis perpendicular to the XY table and started measuring from there. It was complicated.

  20. #20
    Join Date
    May 2010
    Posts
    34

    Re: XY out of square!!!

    I'm sure the machine did not leave the factory like this. I have a 2007 inspection sheet that shows a much better machine.

    More to come later

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