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Rotary Axis Problems
« on: December 12, 2006, 02:45:47 PM »
Well here I go again.  Not sure if I am doing something wrong but I thought i would throw this out there for ppl to look at.

The design says "Carla & Dan" along the top and "10 Years" along the bottom.

I have a file that cuts a design on a .770 diameter tube using the A and X axis.  I set up the A rotary Diameter and configured the toolpath with x as the rotary axis.  So far so good.  I import the gcode and it looks reasonable.  The only minor problem that has existed for many revisions is that the image the toolpath displays is wrapped around the axis backwards.  But when it cuts it comes out correctly.  So ignore that problem.

When I cut the part it came out totally wrong.  The "&" was all the way to the left of the text and "CarlaDan" was crowded together as in the quotes. 

The "10 Years" was way off center to the top text and jammed together overwriting the "0" and "Y" and the rest of the letters just crowded together. 

My first thought was that I was loosing steps.  But the letters look very consistent although crowded.  If I was loosing steps I thought it would be more exaggerated.

Anyhow here is the gcode if you care to look.

Thanks.

Dan.

Offline Graham Waterworth

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Re: Rotary Axis Problems
« Reply #1 on: December 12, 2006, 03:13:04 PM »
What did you use to generate the code, DXF file?

if so post it here.

Graham.
Never give up, time will pass, the cloud will clear, the sun will shine once more.

Offline Chaoticone

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Re: Rotary Axis Problems
« Reply #2 on: December 12, 2006, 03:16:04 PM »
And a picture if of the cut if you will.
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Offline Graham Waterworth

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Re: Rotary Axis Problems
« Reply #3 on: December 12, 2006, 03:29:44 PM »
The only obvious thing in your code is that you don't have a feed rate set (NO'F')

Graham.
Never give up, time will pass, the cloud will clear, the sun will shine once more.
Re: Rotary Axis Problems
« Reply #4 on: December 12, 2006, 03:41:48 PM »
Yeah I usually add the feed rate but forgot.  I take a picture in a bit.

Here is the dxf file.

Thanks.

Dan.
Re: Rotary Axis Problems
« Reply #5 on: December 12, 2006, 05:17:23 PM »
Ok, I think I figured out a problem.  Although I am still not sure if I am causing it.

I added a feed rate of 3 to the file (f3) only once at the beginning.  I also have "use diameter for feedrate" selected in the toolpath configuration.

When I rapid the A axis with either a G0 A0 move in the MDI screen or use the A axis button in the MPG window or my shuttle dial I get about 300 as a reading. 

When the program is running I get about less then 50 as a reading.  About line 486 there is a big G0 A axis move from about 20 degrees to 120 degrees (about).  The A axis accelerates so fast - above 1200 - the motor totally loses position.

So my question is why does it go so fast?   I tried turning down the tuning but then the motor turns so slow during G1 moves it would take days to run the file. Or maybe I do not have the tuning set correctly?  The other option is I turn the "use diameter as feedrate" off but again there is a huge difference in speeds between a G1 and G0 move.

Am I doing something wrong?  This was a problem a long time ago but with version 1.84 it ran very smooth with the existing tuning.

?????

Dan.

Offline Chaoticone

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Re: Rotary Axis Problems
« Reply #6 on: December 12, 2006, 05:44:20 PM »
G0 is a rapid and G1 is a feed. Are you running in feed rate over ride? I saw somewhere to check this box if you are. (See Pic.) Your axis should move at rapid, what it is tuned to in motor tuning, without skipping steps. It should never go over that even if you have your feed rate over ride set to 300 with a feed rate of 99999. This Queue box being checked is supposed to fix it if that is the case. If your motor is tuned right then try to back off of the feed rate. I hope all of this makes sense and is what you are asking.
« Last Edit: December 12, 2006, 05:51:42 PM by Chaoticone »
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!
Re: Rotary Axis Problems
« Reply #7 on: December 12, 2006, 06:32:38 PM »
I reverted back to 1.9.014 and everything works fine.

Offline Chaoticone

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Re: Rotary Axis Problems
« Reply #8 on: December 12, 2006, 06:40:28 PM »
Did you try the checkbox in 2.0.025? If not, I will run some test just for fun.
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!
Re: Rotary Axis Problems
« Reply #9 on: December 12, 2006, 07:03:55 PM »
No I did not try the checkbox... to be honest I wasn't sure where it was.

Thanks for all the suggestions.

Dan.