RepRap: Blog

Fitting the new Flexure Coupling design (with a tapered motor shaft hole) to the X Axis Driver was extremely easy and needed no tools. It did mount 2-3mm above the old one though, so some faffing around with the spacers etc. was needed to line the Drive Screw height up. The result of the backlash test was impressive though:

As a reminder, in the photo above the top row is drawn right to left, the bottom left to right. The two left-hand lines are drawn at the same X coordinate, but in different directions on the Y axis. This allows me to spot any trouble caused by a misbehaving Y axis.

Gap between the top lines is 80μm. Subsequent gaps between the lower lines are increased by 0.5μm. I it's hard to tell if the 2nd or 3rd line from the left lines up best, which would be a maximum of 1μm difference. As backlash happens in both directions, the actual backlash distance would be half that, or 0.5μm max., compared with 1.25μm with the previous (cracked) Flexure Coupling. I'll take that.

If accidents like this keep happening, I may have to design the Flexure Coupling to be a bit more robust, but not having to fit the thing with a mallet may increase its working life...