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This is on a 1999 Haas VR-11B. This machine has been great but recently we started seeing the tolerances slipping and then out to the point where it wont make good parts. Most of the parts this machine runs are +/- .010. I think I have checked everything. It repeats this same amount every time. All the tool lengths and pivot lengths are correct and I can take this program from this machine and it will make a good part on my other 2 VR's.
Encoders, leadscrews?
Is 0,0 in the center of the part? Are the center 4 holes in the correct location or are they off a proportional amount?
0,0 is the top left corner of the material. The holes in the center are correct. The 4 that are out are 5 axis.Quote:
Originally Posted by Jim Dawson
Ahhh, I didn't notice in the picture that they were angled, you have to look really close, it's not obvious.
In that case I'm going with an encoder, or scaling problem. Alternatively, it could be a mechanical issue, maybe even just the spot drill is walking, but probably not that simple. I guess I would dry run that portion of the program and stop at the hole routine and get some measurements. You have to know where it error is coming from before you can fix it. Is it possible the G-code has been edited? or maybe an old/new version? A RevA part and a RevB drawing?
Just to clarify, the holes that are made using standard XYZ moves are correct. When holes are made using 5 Axis positioning, then the locations are out. Correct?
If my statements are correct, then the error is obviously in the rotaries for the 5 axis head. Because you have errors in both X and Y my first thoughts go to parameters. Has ANY work been done on your machine where the parameters could have been changed? Depending on how long the issue has been around, you could scan through the alarms page to see if any parameter changes have been recorded.
I believe that machine has 2 nitrogen counterbalance cylinders. I doubt this has anything to do with your issue, but check the pressure in the tanks to make sure they have proper charge. Do this for your other machines if you haven't checked them in a while just for good measure.
One of the manuals I have shows an Air Spring counterbalance for the rotary. The manual recommends replacement of the spring and rod ends every 2 years. Pg 10 here: https://diy.haascnc.com/sites/defaul...df?0=%253F2316
I am not sure if this applies to your specific machine though.
I would probably want you to make a call to the Haas service line in Oxnard and ask to talk to one of their VR specialists. It's been a really long time since I have even seen a VR machine, I had fun working with them though. You can also check with your dealer to see if they have any ideas; you obviously have multiple VR machines so they should at least be familiar with the series, but I have a feeling Oxnard will be your best bet for solid info.
I didn't offer much help, but I hope your get things figured out quickly. Please update as you get things sorted out.
Good luck!