Need Help!- Circle cutting still have kinks after backlash adjustment.

[alexccmeister]

Hi all,

I have been checking my X and Y axis backlash with a dial gauge and recorded the backlash around 0.2 for both x and y. However after setting the figures in Mach 3, the circle isn't cutting properly and still has a bit of kinks where the motor changes direction. Is this normal or there is a way to get better circle cutting?

Wanting zero backlash in my machine now doesn't seem ridiculous.

Alex

[LongRat]

You may have variable backlash at different points on your machine. When you measured the lash, was it in the same place you are cutting the circle? The other thing to consider is that your backlash may vary under cutting loads. The material can push and pull the cutter around and can highlight insuffient end-bearing preload etc. When you cut the circle, did you skim off a thin amount as a finishing pass? This really helps.

[alexccmeister]

Hi Longrat,

Thanks for your input on this. I will check and see if my end bearing is tight enough. I doubt its the problem but good to check. I am glad you highlighted finishing pass. No, I have not done this and the final pass is the finishing pass. I should try a lighter cut at the end and see if the backlash will come back. But to be honest, when I do a 0.05mm DOC on Delrin, I also get the kink where the motor reverses rotation.

Alex