sortafast
Aluminum
- Joined
- Jul 22, 2011
- Location
- hillsboro OR
So I got a 2002 4020HT With the MP control a month or so ago. It needed ball screw thrust bearings so I went all in and did all of the axes, replaced seals, disabled the cool power to the ball screws (and looped it all back together so the spindle is still connected), I replaced the coupler discs as well so that I wouldn't have to do that crap again later and set the backlash comp. I went through and tuned the axis drives per the doc on fadalcnc's site as the X axis servo was making some noise and I just wanted to make sure everything was fine there. Machine is level. Used my Starrett level that was spot on. So I ran some parts and they fell within the tolerances but they were fairly simple with strait lights and drilled holes etc. Measurements were consistent and most everything was with in a thou and seemed good to go. Now I am moving on to a part with some slightly more complex contours and such and now its getting weird. There are two 0.590" OD circles that it has to cut and those circles are coming out about 0.004" out of round and undersized. The best I can describe it is that at the spots exactly 45degree to the X and Y axis in all 4 quadrants of the circle it is larger in diameter then at the point of the axis it is smaller in Diameter. Slowed the feed down a bunch, didn't really help the out of roundness. Started at 140ipm, went all the way down to 25ipm and same thing. This is in 6061 with a 1/2 Destiny Viper. At the faster speeds it would make the part smaller in the areas that were rounded or contoured. With the first parts at the faster speeds it was like 0.010" to 0.015" undersized on the contour. Slowed the feed and it got better tolerance wise, but even at 25ipm it still undersized the round parts of the contour by about 0.003" on the diameter, but all of strait lines were spot on dimensionally. So its doing something when it transitions from axis to axis like it just can't process fast enough or something. I am not sure where else to look. Could it be a ball screw binding? I am checking the gibs and straps now, but they seem ok. Seems like the issue is in the electronics somewhere and its driving me nuts. Is there a parameter or setting that I am missing or need to check? Need to get this thing spot on so I can get on with some jobs.