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Author Topic: Cut parts are wrong size, CNC knee mill problem  (Read 21514 times)

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Offline Hood

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Re: Cut parts are wrong size, CNC knee mill problem
« Reply #40 on: July 27, 2012, 02:51:39 AM »
LOL no probs Rich.


Sebastian
 With the mention of your cut being 0.2 out I was just wondering if it was  when you were doing code like you posted? If you were measuring the circle cut for both the big dia and then what was left, the core so to speak?
If thats what you are doing then the core will be big dia - cutter dia - 0.2mm as you have a 0.1mm finish on the big dia.
Hood
Re: Cut parts are wrong size, CNC knee mill problem
« Reply #41 on: July 27, 2012, 09:50:01 AM »
It's fixed!!

So last night the first thing that I did was use the drivertest s/w to see how much I could increase the output frequency. My computer was given the green light to 100K but I decided to try 45K first and increase the step/dir to 10us. I then put my dial indicator back in place and ran the set axis one more time to see if they were still within 0.002mm and they were so I decided to make one test cut before changing to Hood's calculated settings. The circle was cut perfectly. At that point I decided to leave my step settings as they were and cut the horseshoe part, and it cut perfectly as well. I did a couple more test cuts at 10mm cut depths and higher speeds and everything always measured up so it seems my problem is fixed!!

Thanks for all the help guys, I still don't understand if it was increasing the freq to 45 or increasing the step/dir time which solved the problem but I don't want to figure that one out now that it's cutting as it should ;D

Cheers,
Sebastian

Offline Hood

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Re: Cut parts are wrong size, CNC knee mill problem
« Reply #42 on: July 27, 2012, 01:26:42 PM »
Good to hear its working, out of interest what do you have the steps per unit set to?
Hood
Re: Cut parts are wrong size, CNC knee mill problem
« Reply #43 on: July 30, 2012, 11:18:55 AM »
1182.change for the x-axis
1183.change for the y-axis

It doesn't make sense since they are the same pitch & belt drive but maybe since the y-axis has to move more weight (the entire table + x-axis motor mount and servo) it's steps are fractionally smaller?

Sebastian

Offline derek

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Re: Cut parts are wrong size, CNC knee mill problem
« Reply #44 on: July 30, 2012, 12:18:27 PM »
Probably a slight difference between the timing pulleys.
Re: Cut parts are wrong size, CNC knee mill problem
« Reply #45 on: November 25, 2015, 09:25:46 PM »
I am a noob having the same issue.  I will wrap my mind around this discussion and hopefully get everything calibrated.   Thanks for sharing the solution.
Cheers