Tuesday, November 2, 2010

Z opto endstop

The new z-axis is very stable and I am confident enough to take the z-axis opto endstop into use for calibrating the height automatically at the beginning of a print. A very simple bracket to hold the opto endstop was printed and fixed to a vertical rod. The endstop is mounted with bolts with springs to allow for easy calibration. Three nuts are trapped in the plastic. The bracket looks like this:

The final endstop installed looks like this:

The printing procedure now is to set the extruder in the middle of the area where an object should be printed, with height close to zero (0-2 cm high). The extruder than will be lowered 2 cm, but the movement will stop when the opto endstop is activated. This is the point where the height is calibrated to zero and the extruder can move up 2 cm to warm up and do a test extrusion.


  1. I believe those optical switches are meant to be used in the other direction, and may not be as accurate when the flag enters from that angle. Otherwise, great idea! I've been having trouble figuring out how to add endstops to Huxley, and something like this might work. Although mounting it on a spring with a screw is a bit easier to adjust, mounting the endstop to the bar so that it can slide along the same axis is a more elegant solution, and should also decrease the area of "thin sheet" parts needed.

  2. @whosawhatsis: You are right, accuracy is a bit less when mounted like this. I did not know, but the specs just confirmed it. I mounted it like this because I though it would be easiest to adjust. I'll keep it in mind for the next opto endstops on X and Y. Thanks for your comment.