Backlash Compensation - your opinions please!

Rick wrote:

It sounds like perhaps you are saying that it does not matter which direction you touch off on...

It does make a difference, the idea is to make sure when you touch off all the slack is away from the touch off.
If you have already made a move in the positive direction the next move if it is also in a positive direction will not have backlash compensation (BLC) added to it and so on. However if you make a move in the opposite direction the BLC will be applied.
In short the BLC is applied when you change directions.
Might be simpler to set the backlash to a high number just to experiment with the results. Once understood set to correct number.

Rick G

Hey, Rick...

I'm being an idiot... got it now. It clicked last night when I was losing sleep over it

It doesn't matter what way you approach touch off because you are doing it WITH the CNC, and the BC is turned on... so it works properly by its nature (provided you drive past any backlash to begin with).

Thanks so much.

R

BigJohnT wrote:

I would assume when you touch off and your using BC you want to be in the middle of the range. How you might do that is a mystery to me. IMHO I don't think many people end up using BC. The "right way" is to not use BC unfortunately.

Since your machine is very small can you just spring load the X and Y to one side and eliminate backlash?

JT

That's a grand idea! It's a Sherline... and I do love the machine for what it is (you just have to respect its limitations). They are notorious for having .003" no matter what you do.... but spring loading... apart from additional wear, might be a good solution when having to hold a tight tolerance in CNC. I've never seen that. Might you have a link to example pics?

I'm used to using it manually... I have a Russian microscope mounted to it... so I do precision work by hand. Backlash is easily compensated for, and I can hold a couple of tenths if I have to. But this CNC stuff is, while simple in concept, full of interesting caveats the more I learn about it. It's certainly a separate skill.

Thank you!

R