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I need to find time to give it a try. First I need to make a gauge for focusing so when I move the bottom beam with the rotary on it I can focus it faster.

 

So I got around to making my focusing gauge. I cut it out of acrylic with my CO2 laser. I love cutting acrylic with that because it is fast and does such a a nice job. The distance I needed from the front of the housing was 23mm.


Tonight I decided to test the chuck out on a cut-off of an old table leg. Since there was green paint on the leg, I figured a sea turtle would be a good test. It worked out pretty well and so far, I am happy with it.

I was wearing appropriate safety glasses and also had a piece of orange acrylic I purchased from J-tech photonics between myself and the laser. If I were smarter, I would have had the camera behind the acrylic so you could see the engraving in the process.

My Lightburn settings were 100mm/sec at 50% power. It was enough to remove the layer of paint, but barely burned the wood. That actually worked out well. I can just put new paint on and use it for further testing.

 

I also "tested" the TAP Plastics fluorescent orange acrylic scrap I had with the diode laser. It definitely did not pass through when I moved it around in front of the beam. There were absolutely no burn marks on the paper backing. I plan to build an enclosure using some of this for the door.

 

Good info. That is why I invested in a quality pair of laser glasses. I have a healthy fear of even the reflected light. I still have a 12" X 12" inch square of orange I ordered from J-tech photonics. I wish I could find some locally that was properly rated. I may have to see if I know anyone with the proper equipment to test it. My other thought was completely enclosed with solid doors and use a camera on the inside with an orange filter on the lens.

 

I did some more testing last night with the rotary on clear glass bottles. I discovered Laguinita's Hopwater (a delicious alcohol, sugar, and calorie free drink) so I had plenty in the recycle bin. I was careful not to damage the part of the label with the barcode on it so I could get my 10 cent deposit back . I painted the bottle with white tempera paint to absorb the laser. I am sure black would be a lot better, but white is what I had. I chose tempera because it easily washes off with water. The colors in the photo look weird because it was filmed though the Jtech laser safe orange acrylic I had.


The result was not awesome, but it worked. The main reason I think there are lines in the engravings below is because I applied the paint with a brush and there were streaks in the paint. I also noticed some black coloring in the engraved portion of the glass. I believe this may have been the laser reacting with the titanium dioxide in the paint to and fusing the darkened Ti02 to the glass. Or, I am overthinking it and I burnt the glass.

The laser being used is a 5.5 watt laser diode.

The lower image here was done with me forgetting to reset the speed and power, so I believe it was something like 6000mm/min at 50% which is why it is so horrible.
I then went to 1778 mm/min at 40% power and it was better. I was basing this off someone else's settings on youtube (70ipm at 40). It actually does not look bad, but there were lines in it and I thought turning up the power would be the answer. I do not think it was.



Below are two attempts with the power turned up.

The top engraving in this image was 750mm/min at 60% power.
The lower was 800mm/min at 85% power.

These two actually look worse than the 1778 mm/min at 40% power due to the slight blackening in some areas. My next attempt will be to airbrush the paint on so it has a thin even coat. I will go with 1750 mm/min at 40% and see if that works. If not, I will try other settings. If I get desperate, I will go buy black tempera paint.