Laser Diode Engraving

Picengraver
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Laser Diode Engraving

Post by Picengraver » Sun Jun 01, 2014 11:14 pm

I engraved this today with a stock Shapeoko and an analog modulated M140 laser diode.
4.0"w x 5.5"h - Baltic Birch plywood - about 1hr 45 min.
John Champlain
Attachments
G Autry PLL.jpg
G Autry PLL.jpg (40.45 KiB) Viewed 3521 times

Staticcling
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Joined: Sun Mar 23, 2014 4:17 am

Re: Laser Diode Engraving

Post by Staticcling » Mon Jun 02, 2014 3:49 am

Looks great!


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nfortosis
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Joined: Thu Apr 19, 2012 12:26 am

Re: Laser Diode Engraving

Post by nfortosis » Mon Jun 02, 2014 5:48 pm

What version of GRBL are you using? I just started messing around with a laser diode and it looks like v.9 has a bug that causes the buffer to pause intermittently when many spindle control commands are used. Have you had this issue or did you find a workaround?
Shapeoko #165: 1m X 1m, Double X, Dual Y motors, Acme upgrade, DW660

Picengraver
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Re: Laser Diode Engraving

Post by Picengraver » Mon Jun 02, 2014 9:34 pm

I used the 8c version that ships with the Shapeoko. I am running some tests with 9d as I write this, and it seems to be doing good for me.

I am not using PWM for my analog signals. I am using an 8bit digital to analog converter circuit to convert Z stepper pulses from GRBL into a 0 to 5v signal for my LD controller, which is similar to a FlexMod P3.

John Champlain

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Re: Laser Diode Engraving

Post by Picengraver » Wed Jun 18, 2014 11:25 am

I laser diode engraved this image yesterday with my Shapeoko 2 and the 9d version of GRBL. I used a gcode sender program I am presently writing running on my Win 8 laptop.

I have been using my Shapeoko and Arduino for a few weeks now, and while I personally find it somewhat limited in features when compared to Mach3, I am quite pleased with its performance and abilities. I compliment all those who have contributed to GRBL's development.

I do not use PWM for diode modulation as many are trying. I prefer to use a digital to analog converter connected to the Z axis. I will soon start experimenting with a simplified DAC circuit using a digital potentiometer, and also will experiment with a rotary encoder driven by a Nema 17 stepper.

I also wish to publicly thank Jeff Woodcock, the original inventor and developer of analog modulation of laser diodes for image engraving, for all his help. He has been a mentor and friend to me, and has freely shared his techniques with all.

Regards,
John Champlain
http://www.picengrave.com
Attachments
Adrianne 3.jpg
Adrianne 3.jpg (60.11 KiB) Viewed 3321 times

Picengraver
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Re: Laser Diode Engraving

Post by Picengraver » Sat Jun 28, 2014 9:24 am

Engraved with Shapeoko2 and GRBL 9e.
About 4.5 x 5.5 inches - 45 ipm - M140 laser diode analog modulated at 1.65 max. amps - Baltic Birch ply - 1.5 hours.
Gcode by PicLaser Lite and streamed to Arduino with my PicSender program.
Attachments
GRBL9ePLLPS.jpg
GRBL9ePLLPS.jpg (31.63 KiB) Viewed 3180 times

Woodworker
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Re: Laser Diode Engraving

Post by Woodworker » Sat Jun 28, 2014 12:29 pm

Picengraver, what are the variations in the z axis GCODE? Are they large swings or just small changes? The reason I ask is curiosity about what the output would look like if used with a spindle.
BRuce - SO2 #4798 - IC's Z axis upgrade, customized Z rail and Z motor mount, spindle Dewalt 611

Picengraver
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Re: Laser Diode Engraving

Post by Picengraver » Sat Jun 28, 2014 5:23 pm

Woodworker,
They are very small. I use G20 mode, and the Z gcode value range is 0 to -.0255 inches. Further, I have the Z axis step/mm set to 393.7008. This gives me 256 power levels for the laser diode.
John Champlain

Woodworker
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Re: Laser Diode Engraving

Post by Woodworker » Sat Jun 28, 2014 5:25 pm

Thanks John, I may have to play with this program with my spindle.
BRuce - SO2 #4798 - IC's Z axis upgrade, customized Z rail and Z motor mount, spindle Dewalt 611

Picengraver
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Re: Laser Diode Engraving

Post by Picengraver » Thu Jul 10, 2014 9:50 pm

I have posted a short video of my Shapeoko2 laser diode engraving an image.

I am using a sender program (PicSender) I am working on to send the gcode to GRBL 9e.

http://youtu.be/TSwfpXVxgGw

John Champlain

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