During this assignment we have been asked to use the Laser Cutter. We currently use the Epilog Laser cutter, 60watts.
My first attempt for this assignment was some decorative pieces. I have tried a few different designs in Rhinoceros ranging from detailed ones to simpler ones to test the capacity of the machine and the materials I could use in each case. They are all 40mm in diameter.
At first I tried using a 5mm acrylic with the following cutting settings:
It didn't work that well with the above settings so a second pass was necessary. Good result, the small parts were not cut completely but were nicely etched. Looks good on clear acrylic but I guess a coloured opaque acrylic would not have such a good result. I later tried it with clear and opaque 3mm acrylic. The detailed parts in the coloured one were pretty bad as the upper part slightly melted and didn't look great and at the same time the bottom part was so badly cut. I tried increasing the speed but the flower wasn't cut, i also tried to do 2 or 3 passes but again I didn't get a good result. I then tried the 3mm clear acrylic. Maybe there is a slightly different density in these two, although they are of the same width. I was pleased with the result.
The simpler designs were very easily cut, both in 3mm coloured and clear acrylic.
The second attempt was to make a 3mm ply press fit shape.
After designing them and nesting them in Rhino, I had to play around wiht the settings as the attempt to cut them using the prescribed by the manual epilog laser settings for wood did not cut through the plywood. I finally succeeded by doing 2 passes to avoid having lots of burn marks [I still did have a burn mark but it wasn't that bad] , here is how it looks:
The notches are a tiny bit narrower than the material thickness. I had designed them to be 2.8mm. This would give a good enough to allow for the ply pieces to join nicely. I also tried it with acrylic.
I did not get a great result at first. The notches had to be a lot wider for the other parts to slide through. Lesson learned, I made them wider by .2mm and it worked just fine.
What was wrong at first? This is also a tip for later: need to measure the material before laser cutting it. It may not be exactly the thickness that is shown in the box but because of changes in temperature this may vary.. Especially with timber [acrylic will not have this issue].
The drawing can be found here.