Sunday, July 10, 2011

RepRap: Frame Complication

{Before and after photos above.}

In the process of building the Y axis for the Prusa Mendel I discovered a problem with how I built the frame. The visual instructions I am following directed me to put three washers and a nut in between the Y motor bracket and the front pulley. This, though, made it necessary to position the pulley gear on the Y motor out  about four millimeters past the end of the shaft. It's not the end of the world, but I was afraid the strain of uneven support on the gear might cause it to break eventually.

On the wiki for the construction of the Prusa this step had a big red note attached. It mentioned this problem and suggested that if the motor shaft is too short to accomodate the spacing washers they could be left out, along with the nut, as well. The two versions are illustrated here.

The shaft, as I said, was about 4mm shallow of flush with the end of the gear. Two washers were just over 3mm, and I had maybe another 1mm wiggle room in how close to the Y motor bracket I could shift inwards. Too close, though, and the extension of the 10mm long screw out of the gear would impact the Y motor bracket. Instead of taking the whole machine apart to remove two washers I removed the motor, got the Y motor bracket out of the way, and used a cutting tool on the Dremel to cut off the washers, carefully.

No comments: