I am a bit desperate and hope that there is someone in this forum who can help me.
As the title say, my K40 produce a line-pattern and i don´t know why.
I run a SKR 1.4 Turbo with Smoothieware. I have tested the “2-wire-method” ( pwm from SKR to IN on Laser PSU) and Pin 2.0 (Servo-PIN) to L. The Result is this pattern.
I have also tested the “1-wire-method” (Potentiometer to IN and 1 Wire from Mosfet Drain to L). Same result.
In addition i have already replaced the Laser-PSU, same result.
I replaced the SKR with a new one, same result.
This is seriously driving me crazy. Does anyone have a clue what else I could do?
Of course I’ve already checked the steppers. The movement is smooth and no rattling.
Fun Fact: My cousin has the same setup and runs his machine without Problems.
Of course I already had this idea, but he doesn’t want his setup to be destroyed. I understand him
By looking at the pattern i guess there is a problem with the pwm signal.
when increasing the speed, the distance between the vertical rows increase too. So the interference frequence does not change, I guess?
well, the setup is written into the board, so is quite difficult to destroy something, also maybe he has done a better cable managing and has no interference. Anyway engrave only a couple of parallel lines 200mm long with 3mm distance from each other.
The only difference to my cousin’s setup is that he used a potentiometer between IN and the level shifter to limit the signal physicaly, as safety precaution. I also tried this, no difference. So frustrating…
The fact that the pattern changes with speed is interesting. I suspect there are a couple of things going on simultaneously.
Perhaps a mechanical issue that’s causing the inconsistent lines and maybe a scanning offset issue or a curtaining issue.
Can you try running a set of a bi-directional engraving with line interval set to 1 mm. Run it at the same 4 speeds in your previous examples. That will tell you if you need to adjust for scanning offset and may reveal other issues.
Also, you should try a test with scan operations at 90 degrees. Do you get the same artifacts or something different?
So this looks a lot better ! It seems the pattern is only made by the x axis.
In the next step I made again 0° engraving with line interval set to 1 mm and got this…
That surprised me a lot! After that engraving I turned the laser off and made some 300 mm/s moves. The Stepper is vibrating like a love toy… Interestingly, I didn’t hear that. The faster the stepper, the greater the vibration, so this explains the greater distance in the pattern at 300 mm/s.
Unfortunately, I’m faced with the next problem. To locate the problem I tried this:
3 different steppers, no difference
2 different connection cables, no difference
2 different stepper drivers ( 2208 & 2209), no difference
I changed the pins on the SKR, to exclude the malfunction of the driver socket, no difference
I tried different steps ( 1/4, 1/8, 1/16), no difference
Agree with @killrob, you should try at different speeds. Does the issue entirely disappear at lower speeds?
Some more questions:
Can you describe more the stepper vibration you’re seeing? Do you actually feel the vibration only at the stepper? Do you get the same vibration on the Y under the same circumstances? What happens if you swap cable ends to the motors?
The last horizontal line test, the top line there is going left to right or right to left? This looks like you have overscan set. At what percentage?
Are you certain you have no wobble in your X gantry, the laser head itself, or in the lens/barrel? This looks more mechanical to me.
Did you try different current settings for the motor in your config?
Ok guys, I have news.
The y-stepper also rattles. While the stepper is installed you can´t hear anything. Smooth movements. But when I disassemble the motor and hold it in my hand it clearly vibrates. The reason for the visibility on the x-Axis is probably the longer belt (600mm).The rattling + the resonance from the belt leads to this pattern. But this rattling is still not normal.
I think it is unlikely that the 2nd skr board is broken. So maybe the drivers are the problem? I have tested the 2208 and 2209 drivers, and the Vref ist ~0.7 on both. This should be ok, for Nema 17 steppers, I think.
All steppers vibrate so can’t tell from your description if this is some sort of unusual vibration. If so, then most likely a driver configuration or compatibility issue.
Do engravings come out dimensionally accurate? So 100 mm in design results in 100 mm in the burn?
However, I suspect you may be able to work around the vibration issues if you can sort out the mechanical issues on your X.
Question, was your laser working normally prior to the board swap?
Where are you getting Smoothieware from? Have you tried C3D’s build?
i don’t know smoothie as firmware but for example, in marlin, you have to declarate which driver are you using for each stepper motor, maybe there is something similar in smoothie?
it vibrates when idle or when in motion? btw mine don’t do such a thing like this, but i use MKS DLC32 as controller with TMC2225 as drivers and GRBL as firmware.
This is a fascinating discussion. I will contribute my own experience in case it has any bearing.
By accident I dropped the laser diode head of my Sculpfun S9 on the floor. Thereafter it exhibited the pattern described above. Close examination under a high power magnifier showed that the head was vibrating in the Y direction. To test this I mounted the head rotated horizontally by 90 deg. Now the pattern showed vibration in the X direction. Yes, it was a mechanical problem in the laser diode head.
Desperate for a solution, since I could not wait for the replacement diode head from China, I tried my hand at repair. I carefully dismantled the laser diode head. I found that the grub screw which secured the laser barrel assembly in the bore of the heatsink was missing. I reassembled it, making sure the lenses were tightly secured, re-focussed the unit and put in a grub screw to secure the laser barrel in the heatsink bore.
That did it, the problem was eliminated and the laser diode worked properly, like new. In the mean time my replacement diode head arrived from China(at prohibitive shipping costs), making me the happy owner of two laser diode heads!
If my experience is anything to go by, mechanical problems are a likely cause.