Author Topic: no success etching in greyscale  (Read 3709 times)

Ken

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Re: no success etching in greyscale
« Reply #30 on: May 25, 2016, 11:49:21 AM »
I have been trying to engrave the attached image for the last 3 week and all I get is 2 black eyes and the black by the ears. I have changed power setting, speeds, resolution and dithering & Gray scale. Do you have any suggestion as to what I am doing wrong? I tested the power levels and it drops from 255 to 225 then quits burning at 1000 speed. Any help would be appreciated because that wall is beginning to look very attractive.

Zax

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Re: no success etching in greyscale
« Reply #31 on: May 25, 2016, 01:59:32 PM »
When you say it stops burning below power 225 at speed 1000, is the laser on but doesn't have enough power or does it turn off?

If it's still on, then lower the speed and the max power value to get a more linear response. You want to get the most range that still burns, say 50 is a very light result and 200 is black then set laser min to 20 or 30 and max to 200.

If the laser just doesn't work below 225 then using dithered is your best bet, and should give good results. If using dithered I would set the min to 0 and max to 255.

dindunuffin

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Re: no success etching in greyscale
« Reply #32 on: May 25, 2016, 03:02:07 PM »
That sounds like the type of results I am getting.   I think there's something different here with some of our hardware.  The light is pulsing on and off, but I can't visually make out much, if any, differentiation between power levels other than high and low.  It definitely is not for a lack of trying.  I've used every combination of speed, power, and resolution I can come up with.

Where did you get your laser kit?  I have an A5 2000mw kit from Gearbest, and it came with an L5 board. 

Ken

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Re: no success etching in greyscale
« Reply #33 on: May 25, 2016, 03:07:23 PM »
The laser is still working and I have burned thru paper, It just doesn't burn wood below 225/1000 speed. If I understand you correctly I need to set laser max at 255 and min to 50 usinging grayscale and keep reducing speed until I get a burn at all power levels! Correct?

Zax

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Re: no success etching in greyscale
« Reply #34 on: May 25, 2016, 03:12:02 PM »
That would be a good place to start, if you need to go slower for the low power to work but the high power is too much you can lower the max laser value.

The problem comes when you don't have sufficient range between min and max for grey scale to function, in that case dithering comes to the rescue.

Ken

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Re: no success etching in greyscale
« Reply #35 on: May 25, 2016, 03:32:00 PM »
tHANKS zAX

BrOncO

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Re: no success etching in greyscale
« Reply #36 on: July 06, 2016, 12:45:56 AM »
hello all, i ave the same problem with my laser in pwm mode, the laser is a 2,5w violet laser from bangood.
Under 220 the laser is turned on but does not burn more, I think the internal driver needs some minimum time for loading.

I measured with a voltmeter the pins on the round board and the voltage is always 12V even on laser pin, I believe that the Round board is only a derivation.

The external driver should be connected directly to the diode? so to use an external driver is necessary in any case remove the internal driver?
I have no idea how it is mounted, it seems is attached with a white paste.

This driver is powerful enough for the 2,5w laser?
http://www.banggood.com/12V-TTL-200mW-To-3W-445nm-450nm-Laser-Diode-LD-Power-Supply-Driver-Board-p-984552.html
Bangood changed the description with 2w max, but on many sites they give it to maximum 3w


Some of you managed to use an external driver with this laser?

Zax

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Re: no success etching in greyscale
« Reply #37 on: July 06, 2016, 06:16:53 AM »
The output should always be 12V, but it is being switched at 1kHz (PWM). Yes, it is the internal current driver board that is not capable of working with the PWM signal so using the board you mention (the same one I have) is the answer.

I have only tested so far using a spare diode as I did not want to disassemble my laser module yet.

sapling

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Re: no success etching in greyscale
« Reply #38 on: July 06, 2016, 07:51:32 AM »
Thanks this is all very similar to what I have been experiencing with my laser so this thread was really good to read. Gotta make some changes to my firmware and check those settings to see if I can get it to do a better job as well.

BrOncO

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Re: no success etching in greyscale
« Reply #39 on: July 08, 2016, 01:46:00 AM »
I have only tested so far using a spare diode as I did not want to disassemble my laser module yet.

Same situation, I'm a little scared about opening the laser.

Zax

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Re: no success etching in greyscale
« Reply #40 on: July 08, 2016, 04:59:32 AM »
I opened mine but found the diode, some of the wiring and part of the board are encapsulated in epoxy... disconnecting the diode and replacing the board is likely to be more difficult that I expected.

It's probably easier to purchase a replacement laser module with TTL (link below for the 2W model) or build one from scratch.

http://www.banggood.com/445nm-2000mW-2W-Blue-Laser-Module-For-DIY-Laser-Cutter-Engraver-p-1055244.html

marcel54

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Re: no success etching in greyscale
« Reply #41 on: July 08, 2016, 11:30:22 AM »
How to link the module laser with TTL on the card L5?

Zax

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Re: no success etching in greyscale
« Reply #42 on: July 08, 2016, 11:49:40 AM »
12VDC would be connected to the board directly, and then you connect the modules TTL input to digital (PWM) output pin 11 on the Nano.

Agastar

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Re: no success etching in greyscale
« Reply #43 on: July 08, 2016, 01:52:06 PM »
You could use Xylene to soften the cured epoxy and then remove it. I would test it first on a scrap piece of electronics first but it's an option.

kn4ud

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Re: no success etching in greyscale
« Reply #44 on: July 08, 2016, 05:40:11 PM »
I removed the fan and see the same board as Zax posted the picture of and it appears to be glued in. It should be easy enough to solder 2 wires into the T+ & T- . So the red & black wires are going to supply 12v to the laser possibly from the ttl module. take the ttl input from pin 11 of the nano. Am I understanding this correct?
Allen