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Re: Another Laser Diode Engraving Thread

Posted: Sat Mar 05, 2016 6:03 pm
by picengravertoo
I wanted to try laser engraving the same image on the back of a mirror with our 6W laser this time. I added a frame to the border so the engraving would blend into the mirrors reflection on the edges. Laser engraving on mirrors gives similar results as spindle engraving Lithophanes, except the image is visible when backlit or not.

I Dithered the image to 1bit Black & White in the PEP5 image editor so the laser would just pulse on/off. I then Flipped the image so it will view on the front properly. I used the Negative selection so the white areas will burn with the highest power which comes out white on the front. The mirror's reflection gives you the black shading effect.

I set the feedrate at 150IPM with a FRC of 20%. Black areas ran at 150IPM at zero laser power (off), then it slows to 120IPM to burn the white areas at full laser power. There are 1,642,528 lines of gcode in the file and the size is 10" X 8". It took 2:07:02 in time to engrave. The hardest part is trying to take pictures of the finished mirror engraving because everything in front of it comes out in the photo.

Here it is backlit.
Mirror6W1.jpg
Mirror6W1.jpg (482.53 KiB) Viewed 2080 times
Here it is without being backlit.
Mirror6W2.jpg
Mirror6W2.jpg (358.51 KiB) Viewed 2080 times

Re: Another Laser Diode Engraving Thread

Posted: Sat Mar 05, 2016 9:07 pm
by AnonymousPerson
Wow, that is really cool.

The concept of lasering a mirrored surface to effect/reduce the mirroring (in controlled fashion) is a completely new thing to me.

Probably wouldn't ever have realised it could be done without your effort + photos above. Very impressed. :)

Re: Another Laser Diode Engraving Thread

Posted: Sat Mar 05, 2016 9:52 pm
by picengravertoo
Thanks,

We actually have used our Varied Intensity laser engraving process with shading results on mirrors in the past. Some examples can be seen on our Gallery page here: http://www.picengrave.com/Gallery.htm

This is the first try with our 6W LD. We have a batch of mirrors here that has an uneven coating on the back, so dithering the image first and then pulsing the laser on/off is more forgiving to achieve good results.

Re: Another Laser Diode Engraving Thread

Posted: Tue Mar 15, 2016 8:27 pm
by picengravertoo
We found this inkscape extension to generate puzzle vector patterns, so I decided to give a try.

http://tuts.ahninniah.graphics/how-to-m ... d-inkscape

We created a 10" X 10" puzzle in inkscape and saved it to a DXF format. We then imported the file into KeyCreator to generate the gcode for cutting it with our 6W laser diode.

We first TTL laser engraved (pulsed on/off) a B&W image on 1/8" Birch Ply the same size as the puzzle pattern we created, then cut through the Birch Ply afterwards. It has a total of 144 pieces.
PuzzlePEP52S.jpg
PuzzlePEP52S.jpg (485.29 KiB) Viewed 2018 times

Re: Another Laser Diode Engraving Thread

Posted: Wed Mar 23, 2016 9:28 pm
by AnonymousPerson
Possibly a weird thought... but would a laser diode caramelize sugar?

eg if you put down a (say) 2" x 2" layer of white sugar, a few mm's thick, then ran the laser diode over it in a pattern, would that caramelize the sugar in that pattern into a solid?

Kind of like https://en.wikipedia.org/wiki/Selective_laser_sintering (SLS) style.

Asking after reading the old http://candyfab.org page, and wondering why they didn't use a laser diode instead. Maybe they weren't available at the time?

Re: Another Laser Diode Engraving Thread

Posted: Wed Mar 23, 2016 9:59 pm
by picengravertoo
Not sure as I never tried it. It may just burn it.

Re: Another Laser Diode Engraving Thread

Posted: Wed Mar 23, 2016 10:55 pm
by AnonymousPerson
No worries. I may just need to try it out myself when I get one. :)

Re: Another Laser Diode Engraving Thread

Posted: Thu Mar 24, 2016 12:23 am
by xfredericox
i've seen that done i think.

also, coincidence?
http://www.manmademayhem.com/?p=1092

Re: Another Laser Diode Engraving Thread

Posted: Thu Mar 24, 2016 12:32 am
by AnonymousPerson
Heh Heh Heh

"Don’t mind the picture, it was a booze-laden night... "

Definitely preaching to the choir. :D

Don't suppose you have any sugar handy, and a willingness to see if your diode laser will fuse it together?

Re: Another Laser Diode Engraving Thread

Posted: Thu Mar 24, 2016 9:21 am
by xfredericox
found this:
https://muzoodesign.wordpress.com/2011/ ... -3d-print/

also, it seems the guy also experimented with doing it in layers, effectively 3D printing with sugar.

http://www.3ders.org/articles/20140422- ... sugar.html