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Dedicated Rotary Laser Made from Scrap and Spares

Discussion in 'Laser Cutters' started by Giarc, Sep 17, 2022.

  1. Giarc

    Giarc OpenBuilds Team
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  2. Mark Carew

    Mark Carew OpenBuilds Team
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    Way to go man your rocking the builds this week! Thanks for the shares :thumbsup:
     
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  3. Rob Taylor

    Rob Taylor Master
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    I love a good scrap build. This is awesome!
     
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  4. David Bunch

    David Bunch Veteran
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    The color scheme is cool and o-ring grippers are a really good idea. Be interested to see how that chuck works for you. I still haven't gotten around to really using my little turntable.
     
  5. Giarc

    Giarc OpenBuilds Team
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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.
     
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  6. Giarc

    Giarc OpenBuilds Team
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    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.
    IMG_20221010_203847__01.jpg

    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.

     
    #6 Giarc, Oct 14, 2022
    Last edited: Oct 14, 2022
  7. Giarc

    Giarc OpenBuilds Team
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    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.
    IMG_20221013_222542.jpg
     
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  8. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Hit in eye with 1000mw 445nm blue laser is a must read thread

    OD = optical density. With unknown acrylic you don't have a proper OD rating, nor a tested and more importantly spectrum analysed report to work from. It may block enough of the near UV to prevent burning the backing paper, could still easily damage an eye. Near UV is much more effective on the hemofglobin (red) inside the veins inside an eye, than it is on a white piece of paper (opposite color spectrum absorbtion etc). It also emits other wavelengths

    Just putting this here - as a very stern reminder - that eyes are irreplacable, this is a public forum, and you really don't wants to use the word "definately" when people could lose eyesight :)
     
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  9. Giarc

    Giarc OpenBuilds Team
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    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.
     
  10. Rob Taylor

    Rob Taylor Master
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    I'd do it like a standard machine enclosure- painted sheet metal with acrylic (orange OD in this case) windows. That's my plan for when I get back to finishing up my laser- cheap 6061 sheet, 3000 series for any bent parts, full hinged door with front window.

    I got the JTech acrylic too- zero reason to skimp on a project like this. You can't know if there are irregularities in unrated acrylic that might cause problems down the line.
     
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  11. Giarc

    Giarc OpenBuilds Team
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    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 :thumbsup:. 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.
    upload_2022-10-17_21-59-14.png

    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.

    IMG_20221016_211428.jpg

    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. :)


    IMG_20221016_211353 (2).jpg
     
    #11 Giarc, Oct 18, 2022
    Last edited: Oct 18, 2022
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