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Author Topic: Cuts uneven when it's cutting arcs  (Read 6432 times)

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Cuts uneven when it's cutting arcs
« on: May 18, 2012, 04:27:18 PM »
I'm using solidworks with solid cam and mach3 as my programs. I drew a part that is a simple shape with a straight cut and some curve cuts. The piece is 1/8 inch flat wood stock. The pattern is one profile cutting 5 passes stepping down till it cuts through.  My question is when it cuts the curved parts it's not supper cleanness, it looks slightly scalloped. I was wondering if this is some kind of motor tuning thing or if my machine is not tuned properly, or for that matter built properly. Is this normal. How clean of parts do you get right off the mill. Am I expecting too much. Can anyone help. Thank you.

Online ger21

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Re: Cuts uneven when it's cutting arcs
« Reply #1 on: May 18, 2012, 05:35:56 PM »
Could be lots of things.
What kind of machine are you using?

Can you post a picture of the cuts?

5 passes is a bit excessive for 1/8" wood. It should come off the machine very smooth and clean, if you use the right tooling at proper feedrates and rpm's.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

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Re: Cuts uneven when it's cutting arcs
« Reply #2 on: May 18, 2012, 05:52:18 PM »
I made my own cnc router mill. I'm new with forums I don't now how to post pictures. My computer is not hooked up to Internet, I use my I phone. Can you tell me how real quick.  So if I slow down the feed rate on  the main screen that should help. I was just hoping to get the part milled faster it already takes a min and a half.
Re: Cuts uneven when it's cutting arcs
« Reply #3 on: May 18, 2012, 07:15:35 PM »
I tried slowing the feed down really really slow it helped a tiny bit but still not super clean. When it comes to the part that has the tightest radius that's when I here the motors step mimicking those little scallop marks and as it tapers off the tight radius to the lesser it gets better. Any thoughts.
Re: Cuts uneven when it's cutting arcs
« Reply #4 on: May 20, 2012, 05:09:11 PM »
I had a very similar problem with my router. I fixed it by going into the Config/General config page and changing the "IJ" mode from ABS to INC. You will find it in the second column from the left about half way down in the box for "Start up Modals"

Hope this helps.

Stuart

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Re: Cuts uneven when it's cutting arcs
« Reply #5 on: May 20, 2012, 05:12:25 PM »
Is the code an arc or is it tiny wee steps?
Hood
Re: Cuts uneven when it's cutting arcs
« Reply #6 on: May 20, 2012, 06:22:44 PM »
It's just a curved line that takes the X and Z axis to perform its sounds like little steps and  when it does that I think that's what causes it to be uneven

Offline Hood

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Re: Cuts uneven when it's cutting arcs
« Reply #7 on: May 21, 2012, 02:48:42 AM »
I was meaning is the code an arc or is it lots of short lines, also is it really the X and Z? Just thought by your initial secription it would have been X and Y .
Hood
Re: Cuts uneven when it's cutting arcs
« Reply #8 on: May 21, 2012, 08:29:48 AM »
Oh ya your right x and y. It's an arc or a spline not short lines
Re: Cuts uneven when it's cutting arcs
« Reply #9 on: May 21, 2012, 08:38:03 AM »
Spencer,
Can you post the gcode, or a portion of it if it is a large file?

Will help to diagnose your problem.

Regards,
John Champlain
www.picengrave.com