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Author Topic: What is the min movement I can command in mach3?  (Read 2025 times)

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What is the min movement I can command in mach3?
« on: June 14, 2015, 12:04:33 PM »
Assuming i have a very hefty reduction (10tpi screw, 10:1 belt reduction) how small of an increment can mach 3 be commanded to move. Will it accept a .00001" command in the mdi dro?

Offline RICH

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Re: What is the min movement I can command in mach3?
« Reply #1 on: June 14, 2015, 01:56:30 PM »
natefoereg,

It all depends on your steps per uinit. The min resolution  would be 1/steps per unit and
most machines will not accurately move to the theoretical min resolution.
IE; My engraving machine has 253000 steps per unit, thus the smallest resolution would be
0.000004", but , the "machines system" requires the capability to be able to move that small,
and, one needs to be able to measure the movement.

To measure your 0.000010 movement would require a calibrated scale ( about $1000 ) and around
a 600 to 900x quality microscope. I doubt very much a belt reduction is any good for that kind movement.

FWIW,
RICH

Re: What is the min movement I can command in mach3?
« Reply #2 on: June 14, 2015, 02:08:35 PM »
I am really asking if I can even input a command into mach 3 for a movement as small as .00001"

I have electronic indicators with amplifiers, 20 millionth mechanical indicators, Mahr/federal electronic levels etc.. I can measure very small movements as well as anyone can in a non temp controlled setting.

I am interested in retrofitting a machine (Moore Jig Grinder) that has lead screws that are more accurate than most micrometers. 

Assuming I have the appropriate reduction, can mach 3 accept and implement a command for a movement as small as .00001"?

I know that their are MANY real world problems with making and measuring a move of only ten millionths. I only want to know (assuming a zero backlash system with a large reduction) can mach accept, understand and implement a move as small as .00001"?

Offline BR549

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Re: What is the min movement I can command in mach3?
« Reply #3 on: June 14, 2015, 02:47:02 PM »
You will have to change the resolution of the DROS in Mach3 (easy)  but yes you can call any move that equals to 1 step of the drive . Mach3's DISPLAY WILL round the last decimal place UP SO for .00001 you would set the dros for .000000 or the min Plus 1 decimal point.

BUT if you quiry the DRO through script you WILL get the Raw number which may be as long as 13 decimals

(;-) TP
« Last Edit: June 14, 2015, 02:49:03 PM by BR549 »
Re: What is the min movement I can command in mach3?
« Reply #4 on: June 14, 2015, 03:27:17 PM »
Thanks everyone!
What is the min movement I can command in mach3?
« Reply #5 on: June 15, 2015, 05:27:24 PM »
Unless the machine has very low stiction/friction, I suspect that you would be very lucky if the stepper or servo could move by such a small amount even though Mach might deliver it the requisite pulses.  This because the incremental torque generated would be too small to move the axis or even the screw.


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