Stepped finish on edges of job

Community Laser Talk
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1

Hi All
I have a K40 with a Cohesion3D board using a laptop running Windows 11
The attached images show the results my machine has just started producing. I have made no hardware , firmware or software changes and this stepped effect has just randomly started to happen.

20241217_124955
20241217_1249551920×933 144 KB

IMG-20241212-WA0002
IMG-20241212-WA0002918×1632 92.1 KB

I have carried out the following:-

  1. Removed , cleaned and replaced the SD card
  2. Cleaned the x axis drive belt , checked for damage and excessive wear without stripping it down.
  3. Cleaned the x axis gantry and rollers then dry lubricated
  4. Swapped out USB cable
  5. Tried using a different image
  6. Tried a variety of speeds faster and slower
  7. Tried a variety of DPI higher and lower
    None of the above have made a difference. I know very little about G-Code but can someone tell me if these two lines of code below are usual?
    G0 X-0.203Y0.101
    G0 X0.101Y0.101
    All other lines are like this
    G0 X-0.101
    G1 X-0.203
    G0 X-0.102
    G1 X-0.203
    G0 X-0.102
    G1 X-0.203

I would be very grateful if anyone has any ideas

Regards
Steve

2

These are simply diagonal moves.

3b. Checked all the coupling set (grub) screws.

3

Hi Mikey
Thanks for your suggestion. I will give it ago later today and let u know how it goes :+1:

4

Hi Mike
In the cut settings editor I have changed the scan angle from ‘0’ where scanning occurs left to right to ‘90’ where scanning occurs top to bottom. This change removes the error on the ‘X’ axis and now it appears on the ‘Y’ instead.? I also turned of overscanning but this had no effect. Im not sure what you mean by the coupling grub screws ? do you mean the coupling on the Y axis joining the 2 drive belts?

20241218_1404211
20241218_14042111920×933 176 KB

Many thanks again for your help :+1:
Steve

5

Yes, and the couplings for the Xaxis too.

That is for something else. Outcome expected.

This part bothers me, unless multiple couplings are loose. Without seeing the same item engraved at right angles for comparison, it is hard to formulate a diagnosis.

6

Hi
I had to walk away from my machine before it ended up in the river. I engraved the same item , same results.Im not sure what coupling(s) you are refering to on the x axis. There is the drive from the motor and associated screws, the belt tensioner at the other end and the screw which holds the belt onto the carriage. The are 4 allen screws on the catenary 2 at each end and associated rollers and locking screws all of which I have checked.
I have found that if I create and fill a square I get perfect results in this case a 100mm x 100mm at this same size I have created 2 rectangles as png images one white one black and these have turned out perfectly (positive and negative settings).I have bought a new SD card which has made no difference. I have not yet flashed my board yet but that will be for tomorrow. For what ever reason my machine now seems to struggle with images (tried png and jpg). Hope I dont need a new board

7

This will either verify or rule out play in your machine. Scale this file to fit your work area and run it at high speed with enough power to mark on cardboard. Make sure to turn all optimizations off. upload a quality photo of the results so we can look over your shoulder.
BacklashTest.lbrn2 (65.5 KB)

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