Fadal loosing something/somewhere - cumulative error or backlash?
Hey guys, fadal VMC15xt here. Making some casting paterns (long programs, surfacing...) and noticed after a couple of those programs, if I use edge finder and touch reference surfaces in x and y direction - I get about 0,1mm and 0,05mm difference, respectively. Thats about 4 thou and 2 thous,I believe.
I tried to measure backlash following procedure - I get ZERO backlash reading (current BL values are good, previous owner determined them good).
I get that difference after running long programs. I used 2 microns (less than tenth) test indicator. Determined the backlash with the small program from the procedure, and via encoder, manually - same reading, both good.
I have tuned the axis driver quite well not so long ago.
Is there anything I am missing?
What could be the cause of my loss of zero point of the piece?
Thank you all, guys.
Re: Fadal loosing something/somewhere - cumulative error or backlash?
Best guess is the screws heat up and change length. Let it all cool down for an hour and recheck.
Ed.
Re: Fadal loosing something/somewhere - cumulative error or backlash?
Quote:
Originally Posted by
ginner
Just a thought - I set the backlash value in thous - vhat if it actually, for example, 1.25 thous? I can't (or can I???) type in that value, if I can measure it? If I really have that situation, it means that, if I have 200 direction changes in one program, i have 200x0.25 thous of error (assuming that I typed in 1 thou as a backlash value).
I hope you get it.
Does this means it is error that I have to live with, if I have large programs with many directions changes?
Backlash does not accumulate. When you go one way you lose the backlash and when you return it returns canceling out.
Ed.
Re: Fadal loosing something/somewhere - cumulative error or backlash?
...you might be able to use G51.3 to comp for different times of the day of running. Tricky but, possible. Try monitoring your Coolant Temp to use as tool to help.
DJ
