laser cutter tips and tricks

Well I went back to the physics lab today to meet with Rich at 1PM (the time he said he'd be there) but he never showed. However, I was able to get back on the cutter we used previously in the fabrication lab (which I'm told is much better anyway) and I had it to myself for several hours. During this time I was also able to meet and talk in-depth with some of the engineering/technology professors and they think the laser cutter is as cool as I do. I talked for a while with Kevin Lee too and he was telling me the kerf width ranges from .008" at the top (face up surface) of the material to .007" at the bottom (face down surface). I still want to measure this ourselves but I was planning on doing some testing with his values.

I also made some small projects today while experimenting on and practicing with the cutter:

Some small boxes/candle holders (and yes I know about the thickness error but I think it looks cooler this way)


Friction fit gauge

Well I just sketched this up in Inkscape to help us with the kerf. Basing it off of your link the idea is we can use this template for every material we want to try and when we get a new material we cut/engrave (blue is cut, red is engrave) one of these with it. When the individual rectangles are loose inside the border you push them all to one end and measure the total gap on the other end. You take that total and divide it by 10 (10 horizontal cuts) to get the average kerf for that material. I'll try and find an upload site to make this .svg available for anyone who wants it.

I'm going to go to Home Depot and buy a 8' x 4' sheet of some really nice hardwood plywood for the club. I'll have them cut the whole sheet up into 16 individual 2' x 1' (slightly less actually) pieces that'll fill the cutter. I'll try this template out as soon as I can with the plywood.

Screenshot of the .svg in Inkscape

Good thinking, we should do both so we can really find a good average. I'm starting to wonder if we should have a laser cutting sub-Forum or at least a sub-Forum for all the machines together where we can collect our work and possibly get a guide going to get people working on their own projects.

For the words in Inkscape: create your text and select it, then under Object -> Fill and Stroke -> set Fill to No Fill, Stroke paint to Flat Color with your color, and Stroke style width to 0.001 inch. Also is it possible to take a 2D sketch in Autodesk Inventor (that perhaps you're using to create 3D shapes with) and export it into a .svg format? I wanted to try creating 3D objects with multiple layers from the laser cutter (like pic below) so I was thinking of making a bunch of 2D sketches and extruding them 1/4" to see what the finished product would look like.


You could probably make this with 3 layers on the cutter, 2 for the front/back and the third for the gears in the middle.

Been practicing in Autodesk Inventor and Inkscape and made both of the pics below. That thing is actually a business card and I figured it was as good as anything to start learning Inventor with. I also need to find a way to generate random polygons in Inkscape (well with a limit on # of sides and size), doing them by hand has to be one of the worst things in the world. I really liked how the pattern came out in the little box above so I'm trying to expand it to a larger cube.


Over a billion hours learning Inventor - this is the top layer showing the cuts/engravings to be made (I'm guessing on all the dimensions)



Random polygons by hand:

Been trying to get the maximum amount of time I possibly can on the laser cutter all this week so I can have some stuff to show off on Friday. First of all I stopped at Home Depot and got a 1/4" x 4' x 8' sheet of some really nice oak plywood for everyone in the club. This stuff looks awesome, feels awesome (both sides come sanded), and even smells awesome so I had the guy cut it down into 16 individual 1' x 2' chunks to fit in the laser cutter. Unfortunately I'm pretty sure I got the new guy and while the width is pretty uniform, the length on some of the pieces can vary up to about an inch past 2' and won't fit in the cutter. I've been thinking I might go back and have them fix it, they better do it for free - they're the ones who fck'd it up. I also got some wood glue and some artist paintbrushes in case any of our designs aren't quite snug enough for a friction fit.

In other news I went ahead and cut out the kerf measurement template from my previous post on the new oak plywood. It was a little larger than I meant to have it but it looks like it'll work very well. Any chance you're going to be on campus with that feeler gauge set? I'm a little nervous about starting cutting full time before we figure this out. I cut a couple test pieces for a torus design of mine and they were way off by about .050" so I definitely feel like we should get this sorted out.

Oak plywood for the club:


Kerf template turned out very well but large


Torus design and test pieces: