Loss of power with multiple passes 60w JPT MOPA...overheat? software issue?

Community Laser Talk
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1

I have a brand new 60w JPT mopa M7 fiber laser with SG 7210 head & LMCV4 clone control board. When running multiple passes (some of my deep engraving projects are over 300), the laser appears to stop firing when the job is nowhere near 100% completion. for a few minutes, i see a red line scan across the marking field, but no physical marking is occurring. eventually the red scanning stops, the timer in lightburn continues going and i do hear some faint noises from the laser head. after several minutes of it appearing to be off, the proper “heavy” firing resumes. this can happen several times throughout the duration of a single job of >150 passes. its almost like the laser or another integral component is heating up, overheating, stalling until it cools, and then resuming. that said, i don’t know how to confirm if that is what is in fact happening, or if this is normal. I’m concerned that something is wrong here and that perhaps all of my 3d layers are not being marked while the task is running. can someone help?

currently running lightburn pro 2.0.00-RC-8 (prerelease) on windows 11.

perhaps i have something wrong in my settings? settings when i notice this occurring:

Layer passes: 270
Q-pulse: 200
Speed: 2050
Power: 80-100%
Frequency: 120-140 range
Interval: 0.025
Image Mode: 3d Slice
Angle increment: 47.8
scan angle: 0
Enable cleanup pass ON- speed 7000 @ 70kHz, 27.5% power, Q-pulse 200; one cleanup to 15 passes

Timing:
Jump Speed: 7000
Jump Distance Limit: 10
Min jump delay: 0
Max jump delay: 0
Laser on TC: 149
Laser off TC: 215
End TC: 100
Polygon TC: 100

I have a video of this occurring if i need to post it.

2

Sounds like overheating.. Is there any way to increase the ventilation?

Double check the optics for being clean.

I have the same source, it has reflection detection and the ability to throttle back the power or shut it off if it overheats or has some other issue.

As far as I know there isn’t really any way to determine what’s going on without specific equipment.

:smiley_cat:

3

I suppose i could open the side of the machine and use a desk fan directed at the laser source.

4

I’ve had mine for over a couple of years and have not been inside it. I know JPT has a cable that makes use of their software to check the internals of the source…

I don’t know how you could check what type of error that may be causing the stoppage.

Maybe @Albroswift has some idea that might help. Is it, by any chance, still under warranty?

***Edit: ***Found this, it seems to be able to monitor any of the error indicators… again, extra hardware and software will be needed.

:smiley_cat:

5

Is it possible the quiet time is the cleaning passes?

6

maybe, but that seems awfully strange. i stuck a piece of paper in the beam path during quiet time and it did not mark at all. its either a very ineffective cleaning pass, or a legitimate malfunction

7

also, why would a cleaning pass take 10 minutes? its set to 1 clean pass to 15 marking passes. seems really strange.

8

Yes, agree.

9

solution to problem: overheating required the sides of the case to be opened and a fan to be directed at the laser source when firing. no overheating since. i will be installing some pc fans in my laser case.

10

So you are saying the laser source gets too hot, throttles down, and when temp drops it throttles back up? What really seems strange is the throttle back up part. Seems like once it stopped burning it shouldn’t start back up. Learned something new.
Thanks for reporting back!

11

yes, precisely. i agree, you would think it would shut down and require a job restart. it would be nice if lightburn creators integrated a feature where this could be detected and projects could be resumed at the appropriate layer in the future. however, now that ive identified the problem, hopefully the problem can be mitigated wit proper ventilation. thanks again for everyone’s help.

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