Laser not Firing in frame mode or manual fire

[Cbob219 (Chris)]

I recently purchased my first laser (cheap Laser Tree 20w on Amazon) to practice with prior to purchasing a more expensive laser. I have two GRBL 1.1 boards (24v power supply) that I’ve tested the laser on, but for some reason, I can’t get it to fire.

The laser is listed as a 20W laser module with a 4W optical laser power output, which is connected to the LSR/TTL port with (PWM, GND, 12V). I’ve confirmed the machine settings have laser mode enabled and I’ve even tested fire when framing and the manual fire option within the move tab, but no luck.

I just want to double check I’m not doing anything obviously wrong before I consider the Laser defective.

[berainlb (PY)]

In principle what you’re describing seems to be correct. But a few things to check for:

1. If you have a 24V board, does the board provide 12V for laser output?
2. Can you take photos of controller Laser port as well as port on laser module?
3. Can you take a screenshot of Device Settings in LightBurn
4. Can you run this in Console and return output:

$I
$$

5. When you’ve used the Fire button in Move window, to what power % have you increased the laser?

[Cbob219 (Chris)]

The board port lists 12V for laser output. You asking for the photos did make me look and find that the wiring was backwards, so that has been fixed (fan turns on now). When doing the manual fire, I was testing various percentages from 0 to 20%, which was the max it let me put.

Laser and Board Photos (Using 12V 3p laser on board)

Requested Output:

$I

[VER:1.1h.20190830:]

[OPT:V,15,128]

Target buffer size found

ok

$$

$0=10

$1=0

$2=0

$3=2

$4=0

$5=0

$6=1

$10=115

$11=1.000

$12=0.002

$13=0

$20=0

$21=0

$22=1

$23=7

$24=25.000

$25=500.000

$26=250

$27=2.000

$30=255

$31=0

$32=1

$100=400.000

$101=400.000

$102=400.000

$110=1200.000

$111=1200.000

$112=600.000

$120=200.000

$121=200.000

$122=100.000

$130=400.000

$131=180.000

$132=80.000

ok

[berainlb (PY)]

Typically you would only have one port on the laser module occupied. Where is the LD-, LD+ connected to? Is that going to the 2P 12V on the board? Or is that going to an internal component of the laser module? Same question for fan.

Do you have PWM on laser module going to PWM on controller? And GND to GND and 12V to 12V?

Can you take screenshots of these things:

1. Device Settings screen
2. Push Devices button in Laser window, then click once on the name of your laser and take a screenshot.

When you push the fire button and increase power. Can you describe in detail what happens? Anything that you observe.

Also, do you have a meter that you can use to test voltages?

[Cbob219 (Chris)]

Yep the LD- , LD+, and Fan-/+ are going to internal fan and laser module. I remove the casing from the photo and confirmed that those were in fact going to the laser and fan.

Yes, I do have the correct connects for PWM, GND, and 12V.

When pressing the Fire button, I’m not really noticing any difference. I do see an additional led on my board light on when pressing Fire and off when turning off Fire. The laser or fan itself doesn’t make any noticeable differences.

I do have a multimeter and do see that the LD-/LD+ port on the laser is reading 12v when firing. When I turn fire off, it does appear to stay around 12v, but decreases over time (was reading around 7v about 30-45 seconds after turning off fire)

[berainlb (PY)]

Change S Value Max in Device Settings to 255 (to match $30 in your GRBL configuration).

Retest.

However I’m not sure if this will make a difference if you went all the way to 20% with power level on the fire button. 20% of 1000 is 200. That should have been around 78% of the power of your laser with $30 at 255.

Can you measure voltage between PWM and Ground at the controller or at the end of the cable? Voltage should be proportional to power with 100% power at likely either 5V or 3.3V and 0% power at 0V. If you can confirm that your board is sending valid PWM then it’s really just dependent on the laser module at that point.