Sunday, November 7, 2010

RepRap: aluminum extruder perfection!

I made a few design decisions since the last OpenSCAD renders. I decided to stick with the vanilla x-carriage so that others can benefit from the design without having to purchase linear bearings. I also increased the size of the heater block at the suggestion of an engineer friend. The other design changes are a result of trying stuff until I got something working. I am not a mechanical engineer by education, nor do I remember much from thermodynamics, so there was a lot of trial and error before the design matured into the following.

The second to last picture shows me tightening up the whole rig with a 3mm rod used to align it. This is critical. I tightened a few designs without the alignment rod and the filament was really hard to push.

One element of the design that is very exciting is the fact that the top most plate of aluminum is cool to the touch! I think this is a result of three plates.

Finally, the PTFE is inside the hot tip, instead of the other way around. This really does make all the difference.

I have printed for about 4 hours without it failing. I'll leave it running for the rest of the weekend and report back on how it is holding together.

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