Week 2 -- Press Fit Construction Kit
I've had the same eyeglass frames since I was 12. Frames that are too small for my head, make me look like Harry Potter, and have that annoying bend in them from being sat on in 9th grade. So for this week's project I decided to make a press-fit glasses kit. While the idea started out as a bunch of different frame styles, it quickly devolved into the 3rd grade giddyness of a Mr. Potato-head style kit. I set out to build a glasses kit with attachable eyebrows, mustaches, and wonky frames. The Harry Potter thing has gotten me pretty far, so why no try out Mr. Potato Head.
Before cutting out each of the parts, I ran a few test cuts to determine a nice press-fit slot width. I got advice to shoot around 4mm from the MAS863 mailing list, but tested a range of sizes from 3 to 5 mm. I decided I liked the feel of the 3.9mm slot the best, but it seemed like everything from 3.8 to 4.2 gave a pretty snug fit. To get the general dimensions of the different parts, I took a ruler and roughly measured my facial features: the length from the top of my nose to the side of my head, length from the side of my head to the back of my ear, and the width and length of my nose for the mustache attachments.
The final kit contains frames, eyebrows, mustaches, temple arms, a linear connector to serve as the bridge and connector to the eyebrows, and a perpendicular connector to attach the temple arms and mustaches.
I did my initial designs using InkScape. When getting ready to lasercut, I used the Ubuntu partition and used the fab modules to generate the .path and .epi files to send to the Epilog lasercutter. There was an annoying effect that the location of my design was mirrored vertically and horizontally in the bed of the lasercutter - i.e. my design in the top left corner would cut in the bottom right corner of the lasercutter. It was also a bit tedious to jump from InkScape to .bmp to fab modules to laser printer. After a little while, I switched onto the Windows partition and used Corel Draw for the remainder of the project. I had to export the design as a .ps file from InkScape and import into Corel Draw (.cdr format by default). Exporting as a .eps, .svg, and .svgz all incorrectly imported into Corel Draw (the node relationships weren't maintained).
The default settings for cardboard left my cuts incomplete in certain points. I wound up iterating and trying several different values, but found the best results with speed:55, power:35, and frequency:1200.