Gelbart Linear Stage

thingiverse

Dan Gelbart is an amazing engineer, designer, and entrepreneur. In the included screenshot you can see a photo of the linear-positioning stage he created, which I've attempted to reproduce here with some minor modifications. This is designed to be a demo object and would need to be modified to take into account material selection. I don't recommend 3D printing this in plastic. Most hobbyist 3D printers will be unable to print the thin .010" walls needed to build the thin-sections which makeup the flexures that make the device work so well. Actually those walls are probably thinner than they need to be, so it may be possible to make this is plastic after all. Ideally this design would be cut on a CNC waterjet cutter out of a single block of metal. The major modification I've made to Gelbart's design is to expand the size of the stage mounting holes for 1" square optical mounts, giving you a 3x3 mounting pattern, and the 4 in-pattern mounting holes around them. Most optical components will slot into a design like this easily, using 1/4"-20 mounting holes. Also, Gelbart's device features a 1:15 lever ratio, whereas this design features a 1:24 ratio. But again, this is an untested, unvalidated copy for demo purposes only. I have no idea how well it would ultimately work. Included also is a model and print for a precision-screw from McMaster-Carr designed to be used with the device to actuate it. The brass sleeve will fit in the bottom hole near the lever and provide the actuation force. I suppose you could put a spring behind this same bottom lever to provide opposite force. There is enough clearance to insert the brass sleeve on the inside of the bottom hole. At the top of the device is another 1/4" hole for a precision measuring-device to measure stage movement. Ideally, this design should produce a stage that can actuate in millionths of an inch with no backlash or hysteresis. And if you want the source of the screenshot, it's from Gelbart's amazing 2012 videos on prototyping called "Making Prototypes" which can be found here: https://www.youtube.com/watch?v=xMP_AfiNlX4