Today, seemingly out of the blue, I found that when my laser (Atomstack S20 Pro) slows down an engrave to do a corner, it seems to be reducing the power so much, that the corners do not get engraved
My settings have not changed, and it used to do these engraves without issue at the same speeds and power.
I’ve checked to make sure that layer settings were ok, and they seem absolutely fine (no tabs set up or anything like that)
I took a look at my machine settings, and they all looked good, but just to be certain, I reset them all to factory defaults, so they now look like this:
But resetting to defaults didn’t make a difference. I then increased $31 to 300, so as to increase the minimum power allowed, but that also made no difference.
I’m really at a loss now as to what is wrong. Any suggestions would be appreciated!
Do you think you still have the same engraving quality overall? Otherwise, you might also have a dirty lens which decreases overall power and might block completely at lowest powers. You could also try at a different material to rule out the wood’s characteristics.
Thanks. The only thing it really mentions is increasing the Max Acceleration on the X and Y in the Machine Settings. I have a “Max rate” and a “Acceleration”, but not a “Max Acceleration”. I assumed it meant just “Acceleration” and my numbers are as standard, already at 1,000 mm/sec which is higher than they say to try to raise them to
Do you think you still have the same engraving quality overall? Otherwise, you might also have a dirty lens which decreases overall power and might block completely at lowest powers. You could also try at a different material to rule out the wood’s characteristics.
I have tried this on a number of different woods, with no change. I did check the lens and noticed a few specs of black that aren’t usually there, so I eagerly cleaned it thinking you were right, but sadly, this made no difference
Also interesting to note, is that when I cut, which I obviously do at a much slower speed and much higher power, it cuts perfectly
There’s a lot of helpful stuff in this post.. I think you’re close to having this sorted out.
$110, $111 and $112 – [X,Y,Z] Max rate, mm/min
$120, $121, $122 – [X,Y,Z] Acceleration, mm/sec^2
What speed are you engraving at? The capture of the Cuts/Layers window shows 3000 mm/min, which is fine. Please confirm.
Fair assumption.. Acceleration in grbl is mm/(second squared) or mm/second/second. (mm per second per second). Grbl doesn’t vary acceleration. It applies the acceleration setting to the motion along the axis.
I thought you might have been attempting to engrave at 1000 mm/sec which is 60,000 mm/minute and a fair bit faster than the max rate.
The thing that’s making me look at this a third and a fourth time are the vertical lines of the smallest square of the ‘constant power’ test. These seem darker than the vertical lines on the ‘variable power’ test and these should be identical in the middle of the line.
Would you be willing to retest with acceleration settings of 300 mm/s^2?
I believe that acceleration is compensated for in the ‘motion planning’ in the grbl controller. The controller turns the power up when commanded speeds aren’t being met. I don’t believe that this applies to acceleration, but I’d appreciate it if you would be willing to check.
I cannot find any documentation from Atomstack describing what the $113 - $115 parameters do, but they seem grouped with the $110 - $112 trio setting the maximum axis speeds. A casual search suggests all the values are usually equal, so they may also be limiting the speeds, perhaps for engraving.
Because GRBL reduces the power based on the actual speed, I think limiting the engraving speed could cause the symptoms you see.
Try bumping those up to the same 6000 mm/min, try the same patterns again, and see if anything changed.
Perhaps if you asked Atomstack nicely, they might tell you what those additional GRBL parameters mean …
Based on the Machine Settings window in Lightburn,
$113 is “A” Max rate (mm/min)
$114 and $115 don’t show up in the Machine Settings, so I changed those to 6000
Unfortunately, after running another test, I got the same results
Assuming those were the $110 - $111 values for the X and Y axes, you now have some useful evidence, plus knowing the other settings don’t do what I guessed.
The “correct” setting for the acceleration is basically the highest value your machine can tolerate without requiring more torque from the motors than they can deliver. The values for other machines with different motors, different motor currents, different laser heads, and so on and so forth, provide only guidance, not absolutely correct values.
Given that Atomstack isn’t forthcoming with any information, you can try increasing the X and Y axis acceleration in steps of 500 mm/s² until the machine misbehaves, then back off by steps of 250 mm/s² until it works again. This won’t damage the hardware, although it may produce awful sounds.
Scale it to fit the platform and run it as fast as it will go in Line mode with optimizations turned off and power set to mark a sheet of cardboard. Any differences from the design will be informative; a photo will let us look over your shoulder.
Always use something cheap like cardboard until you’re certain you’re getting the results you want.
That really solidifies things for me. When you did this test, were the max rates all set for 6000?
From the Console window in LightBurn, Enter the following request:
$i
Followed by Enter (or Return).
Dollar ‘i’ is the request for system information from the control board on the engraver. It should report the build date and firmware version number.
Please select and copy the text from that report in the Console window in LightBurn and paste it into a reply here so I can read every letter of the 6 or 7 line report.
You did that perfectly with the settings report ‘$$’.
