Extruder Problems

Scott and I had our first RepRap session this evening. First off, we made sure the extruder was connected up correctly. When James and I were building Kurzweil a year ago, we lost the "12 Way Connector" that came with our BfB kit. We fudged a solution to get the extruder connected, but it's fragile, and got messed up during transportation across campus for the end-of-year poster session a month ago. Printing a new 12-way connector is an excellent candidate for a future project.

Once we were sure the extruder was connected properly, we performed the tedious but necessary rituals of bed-leveling and z-axis-setting (thus further fueling my desire for one of those well-constrained Mendels...).

We started noticing problems while printing the test rafts. The extruder was clicking, and I could see the filament jumping back, so I released the pressure bearings a bit. I may have gone too far, because the flow from the extruder became pretty feeble, so I tightened them back up half as much as I loosened them. That seemed to make the extruder run more smoothly but the flow was still pretty weak resulting in this test raft:
test raft

I think the problem is either in the tension of the pressure bearings, or some kind of clogging in the nozzle or the insulator, which, if you were wondering, looks like this:
bulgy insulator

I know that the bulge is a problem others have run into. The Bfb kit called for us to cut off a ring of the nozzle to restrain the insulator, but we didn't have the tools to do that and Ian at BfB assured us we'd be fine without it... I'll look around for solutions but if anyone reading this has a take on the situation I'd really appreciate the input.

...And We're Back

While today is not the first time I've worked on the RepRap since I last posted 14 months ago, it is the first time since then I've documented my struggles. Let me bring you up to speed (I'll try to keep it short)...

In the Fall semester of 2009 I took a Computer Architecture course taught by Michael Siff at Sarah Lawrence College. For my independent project I attempted to design a system of modular mechanical logic gates. I seriously underestimated the scope of this endeavor. I was trying to simultaneously:

  • learn Blender
  • learn Skeinforge
  • design complex pieces using Blender
  • maintain and troubleshoot Kurzweil

All while also trying to keep up with an intense Psych class and a very full Music program. Needless to say, I did not succeed, though I learned the hard way that making an idea into reality never goes as smoothly as one first imagines.

Slightly discouraged, and reluctant to set myself up for disappointment again, in Spring 2010 I took a break from RepRap. And then I graduated.

Now, in what may be my last month and a half in the Westchester area, I've set another possibly preposterous goal: wherever I go next, I want to take pieces for a Mendel with me. But this time I have help!

Scott Calvin, an SLC Physics professor, and my excellent Don, wants to learn the RepRap so future SLC students may experience its agony and glory. And what better way to learn how a machine works than fixing one that don't work so well? Hopefully with our powers combined, we will be able to get this puppy running.