Having issues all of a sudden with skipped steps on rasters running LW3 on

Lasers
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Having issues all of a sudden with skipped steps on rasters running LW3 on @raykholo 's Cohesion 3D. I’ve tightened the Gantry belt as mentioned in @Alex_Krause 's post, but I’m still having the issue. It’s sort of unpredictable.

Originally shared by Alex Krause

Started noticing a bunch of shifting in my images… I thought I was missing steps at first… so I checked my X axis belt tension on my k40 and felt a ton of slack in the belt. So I jogged the head to where the hole that leads to the electronics pannel is and tightened both screws that I circled in the second image a 1/4 turn at a time until the belt was where it should be… fingers crossed that this fixes my problem and remember don’t over tighten the belt

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9294f39d9cf3cce1d4bc94180ce8384d.jpeg4160×2340 2.63 MB

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09fd3171f286aff8c6b7a2f7b19a956b.jpeg4160×2340 1.87 MB

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Are you powering off the laser PSU for 24?

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@Alex_Krause yes.

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Happen to know how much current your steppers are running at?

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@Alex_Krause Last I checked the pots were set at .41

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I also have a feeling I’m just doing the engraving wrong…most of what i do is cutting. It’s not as smooth or fast a I’ve seen some people do when they engrave.

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The reason I ask is that the 24v supplied by the laser PSU is only rated at 1amp max @donkjr ​ confirmed this… I also noticed I had more skipping issues with the coiled hose from my air assist attached while going at high speed and acceleration settings

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good info !

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@Chris_Sader try this test image in both image and vector (svg) form.

To test:
…Load the SVG directly.
…Save the .svg as an image and then load.

Laser them both.

You can also repeat them across the work space for more information relative to x-y location.

Its intention is to create a known set of vector moves and raster image that you can then diagnose by looking at straightness spaceing etc.

https://drive.google.com/file/d/0B9A1NYiboK99WUh2NldlMVFGcjQ/view?usp=sharing

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I’ve had this problem since I switched to a cohesion board on anything I try to engrave larger than 2 or 3 inches. I’ve tried everything short of changing my stepper motors

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ab88f71a3aff34ae6003fd54f1e0cc8b.jpeg
ab88f71a3aff34ae6003fd54f1e0cc8b.jpeg3024×4032 1.72 MB

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Try slowing down your engrave speed a bit @tyler_hallberg ​ I saw more problems at 400mm/sec than I did after changing my max speed to around 300mm/sec by doing so you need to back off the power at which you engrave to compensate for moving slower

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Is the cohesion board able to change the micro stepping? If you can back off to 1/16 micro steps you should get more torque from your motors

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We have tried everything. I see no speed change when going from 100mm/s to 400mm/s. I have changed out the controller parts, re did the configure file, update firmware, and nothing helps. Doing smaller things is fine, but it almost gets lost when doing larger engravings.

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Have you tried LW4 to see if you get the same problems?

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I am using LW4. If I turn off join pixels machine runs like garbage. If I leave it on it runs but not the speed i set it at. I just upgraded the firmware again to see if anything has changed. will update shortly

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Any pointers on where to change the micro steps? is that in the config file?

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It would be a jumper if @raykholo ​ added it to the board

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Speed & inertia: do you increase the head weight ? (cable chain, air assist) could be related with max current available for the motor
saying that, i just notice you have only one break in your image so just one (large) skipping. hard to think it could be a software setting.
maybe just an acceleration issue (not computed) before changing direction. sorry just a shout in the dark !!!

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@tyler_hallberg Try to reduce accelleration. That’s where stepps get lost most often.