I was recently contacted by a blind man, Dave, who was interested in getting some samples of the braille I printed on the makerbot earlier this year. I took the opportunity to refine the design a bit more before shipping a few test pieces off to him early this week.
Just yesterday he received them and was immediately able to read them. To quote: "I am enormously impressed. With my fingernail I can feel where the filaments laid down. With my fingertips though, the dots are correct sized, smooth feeling and comfortable to read. I really think this is professional quality stuff."
The next step is to figure out if there's a need for this kind of braille production. I'm currently doing some research on traditional methods of creating braille and am talking with Dave about the feasibility of actually using the makerbot to produce braille.
The trick to getting good braille output is to ensure that the "seam" produced when the extruder moves up a layer doesn't fall on the front face of the strip of braille. I tried messing around with skeinforge to solve this issue but I couldn't reliably fix the problem. My solution was just to add a ridge at the back that effectively displaced the seam.
I created these pieces using Inventor but other programs are definitely possible. I made a test piece in sketchup which worked pretty well.
As with my previous braille design, I extruded the braille font (easily downloaded online) from a flat face (80x10x2mm works well for one line of braille). I provided a .dxf file with all the dimensions I used. The size and spacing of the dots is particularly important in terms of the readability.
http://dots.physics.orst.edu/gs_layout.html provides some of the standard dimensions to consider when making braille.