Thursday, April 24, 2014

Brand Spanking New

Our first print was a great accomplishment, we learned a lot and showed that we were capable of printing a three dimensional part, but we know we can make our printer even better. We completely re-designed the printer to be stronger, more accurate, and more compact. The most drastic change in the design will be size. By orienting the projector vertically instead of horizontally, we can eliminate much of the wasted space our old "box" design. The vertical projector will require the use of two mirrors, which need to be perfectly calibrated to avoid distortion. While adding mirrors adds complexity, it saves plenty of space, our new printer dimensions will be about 14"x12"x16", which is a considerable decrease from the old design, which was almost four times the volume.

The most prominent feature of our previous printer was the large tower holding the build platform that rises out of the resin pool during printing (we call it the "z-table"). Our X and Y resolution for each layer were nominal, but the resolution in the Z direction suffered due to the design of the z-table mechanics. The long arm which connected the table to the mechanics for motion inside the tower separated the center of mass of the table from the threaded rod and stepper motor; the high torque bound the gear and made motion inconsistent. Our new design will stabilize the z-table by adding guide rails on each side of the table, as well as moving the motion mechanics nearer to the center of mass.