Author Topic: Need help w/ daughter's laser engraver not burning  (Read 1321 times)

c0love

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Need help w/ daughter's laser engraver not burning
« on: October 04, 2020, 01:51:20 PM »
I am looking for some help with my daughter's laser engraver not burning. Quick history. I impulse bought this off an auction site for my daughter's STEM club. It was new in the box, but missing setup instructions so I am not sure the exact model. Before I spent time trying to figure out how to put this thing together without any instructions I hooked up the laser and used T2Laser machine control mode. The laser immediately came on, burned the cardboard that I had in front of it. I shut it off and spent a day or two assembling this. Got it all together and now the laser will come on in lower power mode, the laser goes brighter in engraving mode and all the stepper motors move around properly but it doesn't generate any heat and won't burn anything at all. Here is what I know and have tried.

  • The arduino nano is running Benbox 3.1 natively
  • It is a 2.5W 450nM laser
  • There was a label on the outside of the box stating this is a MySweet 2-Axis engraver, but after spending days reaching out to the Amazon seller they can't tell me anything about the engraver. They keep sending me instructions for a different engraver. I think something is lost in translation.
  • It had a software manual from Developower telling you how to setup the BenBox software, but nothing else
  • I have used BenBox, T2Laser, and LaserGRBL all with the same result
  • I have tried plain brown cardboard and white paper
  • I have a few other Arduino nanos lying around so I put one of those on the board and flashed it with the T2Laser default 1.1 firmware, but no change
  • I tried cleaning the focal lens, but no change
  • I tried the Ch341 driver that came with it (2011 version) plus an updated version (2019 version) of the driver with no change
  • I have tried both 255 and 999 for max laser power with no change

She is pretty disappointed this isn't working. It seems to me that even though the laser comes on that maybe it has still gone bad. I was looking at replacement lasers but they appear to be as much as we paid for the engraver and all would take weeks to come from China. Any ideas on additional things to try would be greatly appreciated!

ThothLoki

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Re: Need help w/ daughter's laser engraver not burning
« Reply #1 on: October 04, 2020, 02:27:23 PM »
Make sure the low power button on the top of the laser module is not pressed
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Zax

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Re: Need help w/ daughter's laser engraver not burning
« Reply #2 on: October 04, 2020, 02:39:35 PM »
Are you focusing the laser to the smallest spot size?

If so, and it appears to get brighter but isn't burning then I would first check the voltages. The alser module probably has 3 wires; 12VDC power, ground and the TTL signal.

So when it is supposed to be on full power (either 255 with my firmware or 1000 with others) you should get >=3.5VDC on that signal pin.

c0love

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Re: Need help w/ daughter's laser engraver not burning
« Reply #3 on: October 04, 2020, 04:30:57 PM »
Thanks! Yes I ensured the button on the laser wasn't depressed. When that is pushed it says it is supposed to go into weak laser mode, but it doesn't actually output any light at all.

I will check the pin voltage and let you know. Yes I have it focused down to the smallest pinpoint of light (I tried various sizes as well with no success). In weak laser mode it comes on. When I send code to engrave it gets brighter but doesn't burn.

c0love

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Re: Need help w/ daughter's laser engraver not burning
« Reply #4 on: October 04, 2020, 05:03:54 PM »
I checked pin voltage. I have 3 pin Red, Black, and Yellow.

With the Benbox 3.1 firmware that came with it, I get:
  • Between ground and yellow: 12.25V all the time whether the laser is on or off
  • Between ground and red 4.69V when laser is on. 0V when off. No change in voltage when I adjust the intensity settings (stays at 4.69V)
  • With BenBox software the voltage does go up and down with intensity level changes

With the GRBL 1.1 firmware that I flashed from T2Laser (I used a diff arduino nano) I get
  • Between ground and yellow: 12.25V all the time whether the laser is on or off
  • Between ground and red 4.69V when laser is on. 0V when off. Voltage adjusts as I change the intensity level down to .19V up to the 4.69V. It doesn't go above that for anything aboe 255

With both firmwares when I send the GCode to engrave I see the voltage change up and down as it thinks it is engraving

ggallant571

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Re: Need help w/ daughter's laser engraver not burning
« Reply #5 on: October 04, 2020, 05:28:49 PM »
The typical color codes:
   BLACK     - GND
   RED         - +12
   YELLOW - PWM

Getting 12V between BLACK & YELLOW sounds wrong. Do you see any identification on controller or laser?
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c0love

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Re: Need help w/ daughter's laser engraver not burning
« Reply #6 on: October 04, 2020, 06:36:46 PM »
Actually it looks like the way they have this one wired up it is:
Yellow= VOC
Black = Grnd
Red = PWM

The board and the laser appear to match up. Just as a note, there is a second unused connector on the board labeled "Laser" with just a pos and neg pin, but this came with the 3 pin cable to match the 3 pins on the laser so I have been using that connector.

Zax

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Re: Need help w/ daughter's laser engraver not burning
« Reply #7 on: October 05, 2020, 04:20:36 AM »
It sounds like everything is working correctly.

As ggallant571 noted the wire colors are swapped but providing both ends are the same that's OK.

So the problem is either the beam focus or the diode is bad.

c0love

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Re: Need help w/ daughter's laser engraver not burning
« Reply #8 on: October 05, 2020, 07:03:17 AM »
Thanks everyone. I really appreciate the help. I am fairly confident that it is a bad diode. I have never used an engraver so I didn't realize that it could go bad where the laser still comes on but just doesn't burn. I have tried just about every focal length with no success. I broke down and ordered this laser https://www.amazon.com/gp/product/B07YB9ZHSH/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 off of Amazon. It just got here. I am only using 3 of the 4 pins (just left the temp pin empty). As soon as I plugged it in, it started burning the cardboard. I am going to mount it now and give it a few tests, but it seems to work with the exact setup where the other laser doesn't.

My $90 great deal now cost us $170 which still seems like a decent deal and if she gets some joy out of it, it will be worth it.

c0love

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Re: Need help w/ daughter's laser engraver not burning
« Reply #9 on: October 05, 2020, 07:18:15 AM »
Just for thoroughness of troubleshooting. This is what the laser looks like on the one that isn't burning for us. The cardboard is a few inches away. The same distance where the other laser burns. There was some haloing that I never could fully clean up. I am not sure if this is normal. Tried cleaning all of the lens and they look clean. This was the most narrow I could get the center dot.
« Last Edit: October 05, 2020, 07:21:53 AM by c0love »