Author Topic: Laser turns on but wont burn  (Read 353 times)

bobbyg5301

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Laser turns on but wont burn
« on: June 29, 2020, 11:10:10 AM »
Hi, Everyone!

I bought this engraver at an auction and after hours of research and looking for building instructions and so on, I finally got it put together.

I was having issues getting the laser to turn on at first (all of the motors worked) but after installing the T2Laser software and uploading all of the firmware there it turns on now.

The issue is that I cant get it to actually burn anything. Ive focused the laser on 50 power to a small dot, but if I boost it back up to 255 it wont burn anything, also same thing if I "send G Code" to start a burn. It does the outline, and the laser is on, but wont burn anything.

Any ideas would be appreciated.

Thank You!

bobbyg5301

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Re: Laser turns on but wont burn
« Reply #1 on: June 29, 2020, 11:32:05 AM »
Here are some pictures. one of the laser itself, one of the laser at 50 power, one at 255 power and the whole setup.

Thanks again.

Zax

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Re: Laser turns on but wont burn
« Reply #2 on: June 29, 2020, 02:05:05 PM »
300mW is a pretty low power laser module but at a slower feed rate (try 200) you should be able to burn hard wood.

bobbyg5301

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Re: Laser turns on but wont burn
« Reply #3 on: June 29, 2020, 02:08:26 PM »
Thanks. But when I turn the laser on in the laser controller to 255, and I just keep a piece of cardboard under it, there is no burn at all, so I donít think itís a feed speed issue, at least not yet.

Zax

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Re: Laser turns on but wont burn
« Reply #4 on: June 29, 2020, 03:03:36 PM »
Agreed. I was going to suggest trying that but I just assumed it would burn a nice hole.

So what firmware are you using, have you tried setting laser max or the manual laser power to 1000? If you are using the Eleks firmware it is probably using 1000, although this would be changed to 255 if you either loaded my firmware or uploaded my default parameters.

The PWM output is 8-bit (0-255) and greyscale images are generally 8-bit so everything is a direct 1:1, when you use 1000 as a Grbl parameter it needs to downscale the output so you can get banding in the engraving (depends on the image).

bobbyg5301

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Re: Laser turns on but wont burn
« Reply #5 on: June 29, 2020, 03:13:19 PM »
I followed the directions from one of your older posts, so its grbl 1.1e (I believe).

I tried setting it to 1000 and doing the same and it didnt make a difference. And, yes, i uploaded your firmware and default parameters.


Zax

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Re: Laser turns on but wont burn
« Reply #6 on: June 30, 2020, 03:55:00 AM »
In that case you are getting max power.

As I said 300mW is pretty weak, was it a new module or used?

bobbyg5301

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Re: Laser turns on but wont burn
« Reply #7 on: June 30, 2020, 09:25:15 AM »
It was an ďonline returnsĒ auction, so used for sure. Just how used I donít know. The set looks like it was never fully put together, but Iím not sure.

Zax

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Re: Laser turns on but wont burn
« Reply #8 on: June 30, 2020, 09:47:48 AM »
It looks like an older style controller board, is the laser 3-wire (TTL)?

If not, you could connect 12VDC directly to the module and verify if it will burn or not. If it's a TTL module you can still do that but need to apply 5VDC to the TTL input (you can get that from the Nano if needed).

I suspect it's just not powerful enough although I have no experience with a 300mW module. The lowest I've tested was a 1600mW and that was actually a really good engraver, very small spot size.

Other thoughts, clean the lens but be careful not to lose the spring - also check orientation when you put it back in.

bobbyg5301

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Re: Laser turns on but wont burn
« Reply #9 on: June 30, 2020, 10:59:42 AM »
On the board side the laser is 2 wires, but comes out 4 wires on the laser side.

ggallant571

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Re: Laser turns on but wont burn
« Reply #10 on: June 30, 2020, 11:17:48 AM »
Is the laser side two 2-pin headers (4 pins in total). One labeled +12/GND and the other PWM/GND?
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Zax

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Re: Laser turns on but wont burn
« Reply #11 on: June 30, 2020, 11:41:38 AM »
It must be a non-TTL if only 2 wires from the controller, it probably splits on the module between the laser diode driver and fan.

So it would be OK to apply 12VDC directly and see if it's capable of burning or is just a bright laser pointer.

ggallant571

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Re: Laser turns on but wont burn
« Reply #12 on: June 30, 2020, 01:46:11 PM »
Zax - you still in England? It could have +12 from a power supply, PWM from a controller, and common grounds.
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Zax

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Re: Laser turns on but wont burn
« Reply #13 on: June 30, 2020, 01:51:14 PM »
It could but the picture he posted shows the older red clone board, I have only seen these use a MOSFET.

No - back in Texas, although wondering if that was a wise decision  ::)