For our second BioPrinter platform, we built a custom XY platform from a couple of old CD drives, inspired by this beautiful DIY laser cutter / microfluidics platform from our friends at Hackteria
TL;DR: You pull the mechanisms that move the laser head out of a CD/DVD drive, put two of these at a 90 degrees angle, and voila: XY-platform with a very small build area, but high positional accuracy!
Using the laser head positioning mechanism from a CD drive to build a highly accurate XY platform is not a new idea, of course. Urs at Hackteria credits Peter Jansen
on the RepRap Builders list, who got it from his friend Trevyn, who for all whe know may have gotten it from somewhere else:http://builders.reprap.org/2010/08/selective-laser-sintering-part-8.html
Here's some other versions, via Hackaday
:CNC machine from PC partsBuild a mini cnc machine for $45Blu-ray CNC looks great for branding and engravingLaser CNC from Bluray partsBluray Laser CNC – version 0.2