Prusa Mendel build update #4

In my last update on the building of a Prusa Mendel reprap 3d printer, I finally got everything working in with the printer…if only for a few minutes.

I’ve yet to actually print anything recognizable thanks to a number of challenges along the way.

Once I got the software sorted, I tried printing some calibration cubes. Unfortunately, things didn’t work out as the extruder got clogged with PLA almost immediately. It seems I was trying to force the filament into the hotend faster than it should have been. So then I had to disassemble it, clear it out and try again.

After rebuilding the hotend, the X axis belt was loose so in the process of tightening it, I managed to break all the PLA bushings that were supporting the X axis. I had already fixed these recently so was pretty much done with them at this point. Fortunately, I received some LM8UU linear bearings (from which are smaller than normal ones for some reason) and printed some replacement parts (in blue – I couldn’t be bothered to swap colors to match the previously printed green ones).

X-axis motor mount with LM8UUs

I liked the design of the Prusa 2 parts but wasn’t prepared to cut my smooth rod to make it work so I modified a derivative version of the Prusa 1 idler to fit my LM8UUs (which I posted on Thingiverse in case it would be useful to anyone else). I now have a hybrid X axis since the motor mount is this one (with the awesome integrated endstop trigger) and the idler is a modified Prusa 1 version for LM8UUs.

Prusa Reprap X-end idler for LM8UUs

It all works so I’m happy and I don’t have to worry about snapping off any more bushings. I opted to stick with the old X-carriage as it’s opening is large enough to allow me to remove the extruder and hotend without having to disassemble it (although I may swap in this open x version once I track down the bearings…which leads me to my next issue:

PLA leakage

Seems that once again, I was pushing too much filament into the hotend and I may have had a problem during one of my rebuilds with the teflon tape getting compromised which lead to the ‘leakage’ of PLA above the PEEK block in the photo above.

This should be easy to fix and I’ll try it all again very soon. Once again, the folks in the local RepRap group I belong to helped out very quickly by helping to diagnose the issues just from some photos so I hope to be finally printing by this weekend.

One final thing for Reprap users on Mac OSX – Kliment has released a native OSX app version of Pronterface which I found on his Github while troubleshooting getting a new version of it running…this is great as it means I don’t need to run a couple of command line scripts in order to get Pronterface going anymore. Works like a charm!

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