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Author Topic: Mach 3 Demo Scale issues  (Read 242 times)

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Mach 3 Demo Scale issues
« on: February 08, 2019, 12:46:09 PM »
 I have read many similar posts but none that helped solve our problem. So I am hoping someone can point out what we are doing wrong.
 I have little cnc experience. Everything I know, I learned online in the last month.  I have a D&M 5 lathe with no oem info. I am using an Ohmikron stepper control with micro-steppers (3.5a motors).  This setup was gifted to us with no accompanying documentation.  I am using Mach3 on Windows XP to only control the XZ axis. Spindle is manual. I have the gcode, made with Fusion 360, for the part we are cutting. 
 I ran the code on Mach3 Demo. It cut the piece out in about 25% scale in Z and 200% in X . I read some posts to see if anyone else's solutions would help. We cannot adjust the scale for the axis. There is nothing in the Toolpath window and clicking the Regen Toolpath button does nothing.
 I adjusted the steps per. I raised them incrementally up to 16,000 from 2000 and then worked back down to 9600. The safe position return seemed to match up with the gcode best here. We cannot get the lathe to come apart to do the math for real (it's old), so we were basically trying to get lucky. At one point I was able to cut the piece at about 25% scale in X and Z. Made a few steps per adjustments and then was able to cut one at about 85% scale but was not able to improve it or even replicate it.
 We have had the code gone thru twice and it is definitely ok. So it has to be in our settings. Every time I run the code, the axis run out of position or it cuts in the wrong scale. It never seems to run the same way twice either.  I have tried setting the part position in multiple places, multiple times, I have tried adjusting the motor tuning. I just cannot get this to work right and I don't want to buy Mach3 until we see it work. I understand we are running before we know completely how to walk but I learn quicker hands on.
 Any help in the right direction would be appreciated?
 
Re: Mach 3 Demo Scale issues
« Reply #1 on: February 08, 2019, 11:37:56 PM »
Hi,
do yourself a favour and turn OFF ALL Scaling. Now you have changed your 'steps per unit' values you will have
to set those perfectly accurately otherwise you will never cut any parts to the right size.

MDI a G50. Now all scaling is off.

Zero the X axis with <zero X>
MDI G0 X1     should cause the x axis to move (at max traverse speed) 1 inch (I assume you are in inch units?).
If it does not move exactly 1 inch then change the X axis 'steps per unit' until it does. You need to measure this accurately
and keep at it until a G0 X1 causes EXACTLY 1 inch of movement. Thereafter LEAVE THE STEPS PER VALUE ALONE, it will
stay as is for the life of the machine.

Now do the same thing with the Z axis.

If you wish to machine a part of different dimensions that's what Fusion 360 is all about. Don't try to cheat with G51 scale
commands, it will screw up every time.

Craig
My wife left with my best friend...
     and I miss him!
Re: Mach 3 Demo Scale issues
« Reply #2 on: February 08, 2019, 11:40:39 PM »
Hi,
by the way Mach3 Demo Lathe will only run 50 lines of Gcode. If you want to run bigger files then get a licence.

Mach4 Demo will run an unlimited number of lines but only six minutes before you have to restart.

Craig
My wife left with my best friend...
     and I miss him!
Re: Mach 3 Demo Scale issues
« Reply #3 on: February 11, 2019, 10:59:08 AM »
Thanks I will try that! Appreciate your time.