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Trouble cutting accurately
« on: December 07, 2007, 11:47:01 AM »
I am having trouble cutting parts accurately.  I cut cabinet parts, and have parts coming out up to .0625 big.  I don't think I have had one come out under size.  Accuracy also seems to vary from part to part.  Meaning one part might be correct, the next one plus .0625, and the next and the next one anywhere in between.  My parts are drawn in cad and nested with artcam 2008.  I have been running a cnc for about 2 months, so i don't have a lot of experience.  Any suggestions would be greatly appreciated.  Please laymen's terms only lol.

Dustin

Offline Chip

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Re: Trouble cutting accurately
« Reply #1 on: December 07, 2007, 02:53:31 PM »
Hi, Dustin

Under Config, General Config, "Motion Mode" Are you set to "Exact stop" mode ?

Chip
Re: Trouble cutting accurately
« Reply #2 on: December 07, 2007, 04:07:07 PM »
Yes i am set in exact stop mode.  I have read around this site and am wondering if motor tuning has anything to do with it. I did a g1y48 command and it travels about 48.03125.  I did the same along the x and got a similar result.  Thank you for the reply.

Dustin

Offline Chip

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Re: Trouble cutting accurately
« Reply #3 on: December 07, 2007, 04:25:42 PM »
Hi, Dustin

Looks like your "Steps Per" inch in motor tuning are Off, a few to many.

That will do it every time, Don't now why it's inconsistent though.

Chip
Re: Trouble cutting accurately
« Reply #4 on: December 07, 2007, 06:56:23 PM »
Would you explain the process of tuning them for me?  The model on the motors is Keling Technology  KL34H295-43-8A.  Is there a manual that can be purchased for the mach 3 software?  I really would like to understand the cnc world, its hard as i am sure you know to make the switch from table saw to the cnc.  The software alone is mind blowing. 

Dustin

Offline Chip

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Re: Trouble cutting accurately
« Reply #5 on: December 08, 2007, 01:37:21 AM »
Hi, Dustin

Above, Tutorials, Documentation, Using Mach3Mill , Hears a shortcut to the Manuals.

http://www.machsupport.com/documentation/

"Steps Per", Number of pulses to your stepper cont. to move 1 inch, Looks like your pretty close, Just need to reduce the steps per value a little.

To calculate it, Number of steps it takes to turn the stepper motor one turn, std. full-step= 200, half-step= 400, 10 micro step=2000.

If your stepper motor is one turn, std. full-step= 200 X 10 turn ball screw = 2000 "steps per.", 10 micro step=2000 X 10 turn ball screw = 20,000

Or std. full-step= 200 X 10 turn ball screw X 2 to 1 reduction = 4000 "steps per."

"Velocity" is your top speed G00, With no lost steps, Make your moves 5-10 inches if possible, G00 X10.

"Acceleration" is from a stop to full speed or full speed to a stop, With no steps lost,Use G00 or F100 to test.

Reduce the values by 10% or so, "Velocity, Acceleration ", It's a balancing act Hear.

G01,2,3, "G01 x10 F1", Will override these speeds and run at 1 inch per minute

The Manuals have all the Info you need, It's a bit of a steep climb, But there is a Plato up there.

Hope this Helps, Chip