Wednesday, April 1, 2015

Practically everything that could go wrong with my RigidBot 3D printer went wrong.

After replacing the main circuit board with a RUMBA to no effect, replacing the extruder motor to no effect, replacing the extruder flat cable to no effect and burning filament dregs out of the extruder nozzle to no effect, I happened to notice a small electrical flash in the connector from the extruder motor to the circuit board socket.

So I chopped off the extruder motor socket and soldered on individual sockets for each of the four wires. Finally, at last, I got a proper response out of the extruder motor. So I ran tests for a few hours and it all seemed to be OK and then the extruder stopped for no obvious reason.

Well the only piece in the whole extrusion chain that I hadn't replaced or repaired was the teflon tube in the filament pre-heater. And sure enough when I extracted it I found it had partially melted to partially fill the filament hole, making proper extrusion impossible. A bit of creative gouging with a small drill bit restored the hole sufficiently to allow filament to pass through.

And finally, after more hours of testing, I have a working 3D printer. I put all the original parts back in and it still worked :).

So I've started trying to catch up on my backlog of needed enclosures. Obviously I don't need a special enclosure for a RUMBA board because I've put the original board back into the enclosure already supplied.

I tried making an enclosure for my Parallella. This required me to re-construct the SolidWorks example on Thingiverse here into a parametric model I could change to suit my requirements, specifically I only had a 40mm x 40mm fan and I wanted to continue using the existing 5V power socket.

Yak-shaving to make a 3D model

I wondered if OpenSCAD was the quickest and easiest open source 3D modelling program. I wasn't prepared to pay the SolidWorks licence fee considering how infrequently I would be likely to use it. I looked at FreeCAD and it seems an interesting parametric design program. Then quite fortuitously I found SolveSpace which has only recently been made open-source but seems much more powerful and capable than FreeCAD. And there is a Mac OS X version as well. The trouble was, for the simple box enclosures I want to make OpenSCAD simply makes better sense to me. I suppose it appeals to my programmer background.

Plan B

In the meantime, I ordered an enclosure and cooling fan for the Parallella from Ground Electronics just in case I found making a usable enclosure too tedious or too difficult. The Plan B case arrived today and although I was very close to a working enclosure, I couldn't get the correct screws so it seemed easier to use this enclosure and get on with other things.