Tuesday, June 14, 2016

Secret Project Laser

The school where The Child goes to wanted to make some mallets with the school's R logo on them.   Someone much cleverer than me in the ways of woodworking made the mallets, and figured out a way to use blank tiles of white oak to put the mallet together.

I had to convert the pixelated logo into a vector drawing of the logo in InkScape, which I surrounded with boxes the size of the wood tiles.
When I got to the Maker Space, I laid the side of a cardboard cereal box into the laser cutter, and had it etch the design onto a cardboard cereal box so I'd know where to put the tiles.

I went back into the CAD program and added the black within the logo.  For whatever reason, CADQ hadn't picked up the black bits.  This was a good thing for cutting the guide, but it took me a few minutes to figure out how to add solid hatching.  The default setting for the cutter is to use a continuous red line for cutting through object, and black for a rastered etching.  

Since I didn't want to cut out the tiles, I removed the bounding boxes on CADQ.  Then I did a test run on the obverse side of some extra tiles.  In this photo you can see how the cardboard got sliced out around one of the stars before I got the laser to pause.  

The blanks laid out on the cardboard guide in the laser cutter's bed (note laser siting dot in upper right-hand corner).  The only problem with the cardboard was that it was folded and warped in a few places, so while it laid flat when the tiles were on it, it didn't want to stay flat when they were off, which was a source of worry.

The process of cutting and etching the tiles took about 25 minutes.   I'd say the first 20 was the laser going back and forth like an old Apple ImageWriter burning in the R's and the last five minutes was spent outlining.

The finished tiles, with the center one removed to show the cardbard's guidelines beneath.

The tiles were .25 of an inch thick, and I set the laser to cut at .13.  When I did an experimental tlle at .25, it nearly cut out the R and there wasn't much of an increase in contrast on the engraving.  I think if I had manually fiddled with the laser's power and the sled speed, I could have changed how things came out.  However, at .13 inches burning into white oak, there was minimal scorch marks.  

A finished tile.  Adding cut line around the engraving made the design pop out of the wood.

Once they were done, I got the white oak tiles back to another parent, who is wiser in the way of wood, and who put them onto the mallets.

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