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Author Topic: Mach 3 backlash not working  (Read 577 times)

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Mach 3 backlash not working
« on: August 12, 2018, 02:25:57 AM »
I can not get mach to compensate for my backlash. Ive searched the forum and tried the 50/50/50 stuff but it seams like the backlash feature has been disabled. Im running .66 version of mach 3... Any ideas?
Re: Mach 3 backlash not working
« Reply #1 on: August 12, 2018, 02:38:29 AM »
Hi,
what in particular is it not doing. There are a number of circumstances that no backlash compensation
can fix. One in particular is climb milling, if your machine has significant backlash to try to climb mill could result
in disaster with the tool 'pulling' the lash of the axis into the cut zone all in one rapid lump. No amount of software
will save you from that.

Craig
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     and I miss him!

Offline ger21

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Re: Mach 3 backlash not working
« Reply #2 on: August 12, 2018, 06:35:12 AM »
And if you are using a motion controller, it's possible that it doesn't support backlash comp.
Gerry

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Re: Mach 3 backlash not working
« Reply #3 on: August 13, 2018, 12:56:41 AM »
I have .002" in X .003" in Y and .010" in Z. It is the Z that is the issue. It does not matter how much backlash i try and compensate for, any value entered has absolutely no effect.  Im test backlash by simply comanding movments in the dialog box, i.e Z.1, Z.0.

I am using a galil motion card but I have read other posts explaining the backlash compensation should still function.

Offline RICH

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Re: Mach 3 backlash not working
« Reply #4 on: August 13, 2018, 08:45:57 AM »
Quote
tried the 50/50/50 stuff


The 50/50/50 rule that I posted  is a good  general setting. To see just how BC works you need to play with
the individual settings  and carefully watch what is happening in the movement. BC is only done when change of direction takes
place. I don't know what the mechanics of your  Z axis mechanical makeup is and in that light I can only say that the best approach would be to eliminate the backlash. BC can be used to make a poor axis become functional but only to some degree of accuracy.  Don't use ver 66 here so no comments on that versions use. I would suggest that you profile the complete Z axis travel in both directions of movement  to check variance in accuracy and then strategically test BC at some locations  based on what you found in profiling of the axis movement.

RICH
« Last Edit: August 13, 2018, 08:56:51 AM by RICH »
Re: Mach 3 backlash not working
« Reply #5 on: August 13, 2018, 03:27:14 PM »
Thank you for the suggestion of mapping does the Z.
I have already eliminated as much of the backlash mechanically as possible. The machine is an old Kondia NC machine and Z movement is actually quite stiff.
Re: Mach 3 backlash not working
« Reply #6 on: August 15, 2018, 07:12:46 AM »
I have tried adjusting the backlash compensation and suttle wheel amount but they seam to have zero effect.  Absolutely no change regardless of values entered for either.

Offline RICH

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Re: Mach 3 backlash not working
« Reply #7 on: August 15, 2018, 07:24:55 AM »
Backlash is functional in Mach3, never tested it with version 66, does work in 62.
I echo Jerry's reply ............ And if you are using a motion controller, it's possible that it doesn't support backlash comp.

BTW, Try setting a large value for backlash ( say .1" ) with a slow shuttle wheel and  backlash speed setting. 

RICH
« Last Edit: August 15, 2018, 07:29:26 AM by RICH »