Engraving skewed, cutting fine

vortexblue
Posts: 4
Joined: Tue Mar 06, 2018 9:39 am

Engraving skewed, cutting fine

Postby vortexblue » Mon Apr 02, 2018 5:16 pm

Hi,
I have a 1309 machine that I recently replaced the X motor driver on. I typically only cut plastics, but I recently tried to engrave and I had a weird result.

The scan goes from *bad* (out of where it should be), to *good* (right where it should be).
-The issue is not exclusive to any software (tried 2 different versions of RDWorks and Lightburn Beta)
-it happens anywhere on the bed (not location based issue)
-It's consistent: RDworks scans from top to bottom and the issue shows at the top. LightBurn goes from bottom to top, so the issue is at the bottom.
-it's not file related: both test files were created in their respective editors (open software, new file, text tool)
-I tired adjusting the backlash settings and it just made errors appear; I have it set to 0
-I tried adjusting the 'reverse interval' settings; this made it no better
-I tried toggling the 'pwm rising edge' box; no luck.
-steppers have been calibrated: 100mm square measures 100mm square.

I feel like this might be a settings issue, but I'm not sure what it could be.
Any thoughts?


Image

vortexblue
Posts: 4
Joined: Tue Mar 06, 2018 9:39 am

Re: Engraving skewed, cutting fine

Postby vortexblue » Fri Apr 06, 2018 7:23 pm

Update:
Not cutting fine.
Image

That file started at the upper right and went anti-clockwise. the bottom 2 are the same as the top 2, only the cut path runs twice.
On the 3rd one you can see some X steps are missing, and in the 4th one, there are even more X steps missing.

Any thoughts?

Techgraphix
Posts: 471
Joined: Fri Jan 20, 2012 1:39 pm
Location: Appelscha, the Netherlands
Contact:

Re: Engraving skewed, cutting fine

Postby Techgraphix » Sat Apr 07, 2018 3:43 am

Mechanical? A loose timingpulley for instance.. X and Y not square (perpendicular)
Loosing steps due to a weak motor, wrong currentsettings, wrong settings for acceleration, jerk etc..
This can have many causes..
Kees

vortexblue
Posts: 4
Joined: Tue Mar 06, 2018 9:39 am

Re: Engraving skewed, cutting fine

Postby vortexblue » Sat Apr 07, 2018 6:56 pm

-I tried a number of different things; backlash compensation, reverse interval, laser alignment. With each step, I could see a difference, but not an answer to the issue. Things like changing the backlash introduced a different 'jog'.

-I tried toggling the PWM rising edge:
Image

-I tried changing the stepper resolution from 6400 to 3200 (I resquared the stepper length it before this test)
Image

-It was suggested that it could be losing steps even during cutting, so I received a test file to try. I ran it, and they were right:
Image

-I pulled the X stage apart, cleaned and lubricated it. Tension was re-set and tested again with no change.

-I re-ran the file with different amperage settings; 2.0A, 3.0A, 4.0A, 5.2A, 5.8A (what it was set at originally), 7.0A. The problem was repeated exactly to the T.
Image

-I re ran the file MUCH slower (speed 100, then 20, then 10). The issue got better, but it is still losing steps.
Image


So here's where I'm at:
It loses steps only in the X direction, Only to the right. It's not bed location based. I think I can eliminate software (I've tested with lightburn, I've created new test files, etc). I think I'm looking at a hardware issue. The Y motor driver recently had a failure - not long after I moved the machine across town. Could I be looking at a X driver motor failure, or does this seem like it might be X motor?

Thanks so much for any suggestions. I'm up for testing/ trying out anything you might think of.
-Chris

SWMS
Posts: 158
Joined: Mon Jan 06, 2014 4:28 am

Re: Engraving skewed, cutting fine

Postby SWMS » Wed Apr 11, 2018 3:25 pm

Could be one of those process of elimination things you have to go through. Try replacing the x motor and driver with a cheap one if you have a closed loop stepper and just see if it’s that.

I have a wobble issue on my y axis and I think it’s down to friction and the axle not being true. I feel your pain trying to work out the causes of these problems. I’ve spent £75 replacing bearings, pulleys and a precision shaft.

vortexblue
Posts: 4
Joined: Tue Mar 06, 2018 9:39 am

Re: Engraving skewed, cutting fine

Postby vortexblue » Wed Apr 11, 2018 9:13 pm

Image

Success!

It appears to be a bad driver. I replaced the one in the picture with one from LightObject and we're good to go. I will still run the pattern file I ran earlier to see if it'll miss steps, but I'm feeling confident now.

Now onto fun stuff like tuning it for good etching, adding a 2nd tube, adding a red dot and experimenting with my unused rotary assembly!

SWMS
Posts: 158
Joined: Mon Jan 06, 2014 4:28 am

Re: Engraving skewed, cutting fine

Postby SWMS » Thu Apr 12, 2018 12:40 am

Hooray! Fantastic news. I would not have thought a driver could do that but I suppose it makes sense.


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