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Steps per unit difference
« on: January 03, 2017, 01:06:49 PM »

Confused and frustrated

Stepcraft 420 with mach3

I read on here that ideal steps per Unit in motor tuning is 133.333333.

I tested this on a 8cm square profile job. Result: x-axis= 8 cm, but the y-axis=8.7.

I went then to the section settings where there are steps per unit set button to help you test how each axis moves per unit.
x and z are okay, but moving y double than its command.
Mach 3 suggests automatically adjust it and we have the half of steps per unit for the y-axis, so 66.6.

I then tested and found my square with x = 8, y = 4.4

What happens?

Offline RICH

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Re: Steps per unit difference
« Reply #1 on: January 03, 2017, 04:59:57 PM »
Go to Settings ( Alt-6),  in lower left side of screen you will find Axis Calibration, click the Set Steps per unit button,
select the axis and click ok, input how far you want the y axis to move, then click ok.
The axis moves and then the screen asks you how far it moved, you input how far the axis actually  moved. It then  asks
you if you want to accept the steps per, click yes.
The steps per value it calculated will be saved to the motor tuning.

Now test that same axis again the same way. You may need to do it a few times and each time Mach's calculated value will get closer to as perfect as you can measure the actual move.

When done ie; you commanded say 8.0000 and it moved 8.0000, then there is no need to continue doing it.
So then Config> save Settings, open the motor tuning and note the step per unit value for the axis.
Go out and back into Mach. The steps per unit should be correct to what you noted.

The input move should be as long as possible. How repeatable or accurate things are totally depends on your machine and how well you measured the actual distance moved.

NOW....one last thing

Go read the MACH 3 manual!  ;)

RICH

Offline RICH

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Re: Steps per unit difference
« Reply #2 on: January 03, 2017, 05:03:24 PM »
BTW,
The other site that you posted on ............
Not sure they know what they doing ???

RICH
Re: Steps per unit difference
« Reply #3 on: January 04, 2017, 03:30:17 AM »
I read the manual, I followed these steps and in settings section (Alt-6) everything is allrightr. The machine moves accurately. But in Program Run, when I load a g-code file with a simple square, the y- axis is wrong. I will insist and test it several times, and then restart the program.

Another thing: the guys from stepcraft advised me to buy Uccnc and motion controller for the best results. Mach 3 is not so suitable for stepcraft. What do you think?

Thank you so much. I am a beginner, but I love to learn.

Sorin.

Offline RICH

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Re: Steps per unit difference
« Reply #4 on: January 04, 2017, 07:05:35 AM »
Quote
Another thing: the guys from stepcraft advised me to buy Uccnc and motion controller for the best results. Mach 3 is not so suitable for stepcraft. What do you think?
Ask the guys WHY Mach3 "not so suitable"?

What I think about Stepcraft does not matter.

---------------------------------------

As a beginner you need to educate yourself about CNC, Controller Software
( MACH3 and others), different CNC software that provides for generation of the Gcode to do CNC nachining, what hardware is available ie; power supply, drives available, break out boards etc. Only then can YOU make intelligent decisions which are not based on what someone else or "the guys" say.

Spend your money wisely to satisfy current and future needs.
 
RICH
Re: Steps per unit difference
« Reply #5 on: January 04, 2017, 08:26:54 AM »
Thank you, Rich!
I will continue to investigate.