Mirror Laser Engraving 6W LD

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Picengravertoo
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Mirror Laser Engraving 6W LD

Postby Picengravertoo » Sat Mar 05, 2016 12:58 pm

I wanted to try a laser engraving on the back of a mirror with our 6W LD. 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 5472 times


Here it is without being backlit.
Mirror6W2.jpg
Mirror6W2.jpg (358.51 KiB) Viewed 5472 times

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Picengraver
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Re: Mirror Laser Engraving 6W LD

Postby Picengraver » Sat Mar 05, 2016 7:02 pm

:respect)

banjags
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Re: Mirror Laser Engraving 6W LD

Postby banjags » Wed Dec 21, 2016 4:04 pm

I have a 6 watt diode too and what been wanting to do this on mirrors as well. I am using Arduino and Ramps so I have to us the 3d laser settings with in PEP 5. There FRC settings are not in there. Is another way to accomplish basically the same product as you with my setup?

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Re: Mirror Laser Engraving 6W LD

Postby Picengravertoo » Wed Dec 21, 2016 4:15 pm

The image was Dithered black & white, so I only used the FRC to speed it up in the black no laser power areas. You don't really need the FRC. You just have to be more patient waiting for it to finish. ;-D

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Re: Mirror Laser Engraving 6W LD

Postby banjags » Wed Jan 11, 2017 10:35 am

Figured I would share my results with you. Turned out rather well I must say. Not quite 100% but pretty close. I am impressed with the detail considering the larger spot size on the 6 watt. The 2 tigers are 10cm x 10cm and the wolf is 7.5cm x 7.5 cm.
Attachments
Wolf.JPG
Third Attempt
Wolf.JPG (311.68 KiB) Viewed 4871 times
Tiger2.jpg
Second Attempt
Tiger2.jpg (126.7 KiB) Viewed 4871 times
Tiger1.jpg
First Attempt
Tiger1.jpg (131.79 KiB) Viewed 4871 times

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Re: Mirror Laser Engraving 6W LD

Postby Picengravertoo » Wed Jan 11, 2017 10:48 am

:Bravo!

What Dithering Algorithm are you using? I prefer Atkinson because it's adjustable.

Thanks for posting your results.
Jeff

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Re: Mirror Laser Engraving 6W LD

Postby banjags » Wed Jan 11, 2017 2:45 pm

I did not use any Dithering. Just straight PWM. 5-255 power, 1200mm/min

Would I get better results with dithering?

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Re: Mirror Laser Engraving 6W LD

Postby Picengravertoo » Wed Jan 11, 2017 3:05 pm

With a Dithered image, the laser just pulses on/off which will give the illusion of shades. It's more forgiving because the back coat on the mirror is an inconsistent thickness and has imperfections.

banjags
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Re: Mirror Laser Engraving 6W LD

Postby banjags » Wed Jan 11, 2017 3:22 pm

Hmm ok.. Its worth a shot. I shall try Atkinson since that what you use and your engraves have turned out real nice.

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Re: Mirror Laser Engraving 6W LD

Postby banjags » Wed Jan 11, 2017 3:25 pm

What constant do you use with Atkinson? or does it vary from image to image? Whats a good starting point?


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