Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: sdougm on September 07, 2018, 05:11:35 PM
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Hi folks!
I buyed a STB4100 USB board and i cant make backlash work, any1 kow if this board support it?
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Ask the people that sold it to you.
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Hi,
even if the controller does support backlash compensation, and given the boards Chinese origins it seems unlikely, it
still does not cure backlash.
The software will for instance 'take up the lash' if you reverse direction, rather like this:
G1 X100 F500 ;the machine cuts in a straight line until X=100 at 500mm/min
G1 X0 F500 ;the machine because of backlash compensation travels at reduced acceleration (of your nomination) in the -X direction
the distance of the backlash of that axis (that you nominate) say 1mm. The machine will now cut in the negative X direction until
X=0
Thus the machine absorbed the backlash. If however the cutting forces are such then the axis can move the distance of the backlash and the software is not
only unable to do anything about it it doesn't even know, Mach is not a feedback system.
Backlash compensation is useful under a number of limited circumstances but is not a cure and in other conditions, particularly reversal of cutting
forces it will fail to be of use at all.
Any and all discussions on backlash recommend solving the backlash mechanically, a software solution at best a patch up.
Craig