RepRap: Blog

Many thanks, looks great! thanks for sharing ;-)

I would prefer that PTFE barrel wouldn't be glued, because extruder s a bit problematic, plastic can block there - at least for novice users...

Also I don't like to make flat faces on stepper motor shaft...

I would instead try to use this ideas:
http://www.thingiverse.com/thing:1625
http://www.thingiverse.com/thing:1935
 

Nice design apart from the unsupported PTFE. Is there anybody outside Bath that has used a PTFE insulator like this and not had it fail?
 

Nice design indeed, and nice big gear !
 

very nice, i like your design, once i get printing i think i might try to make that my next one, with gearing that big could a person go down a size on there stepper for the extruder, saving both wight and cost. the less mass to move around the better i think but i do like that one nice and simple i think. and i like the fact that you don't have to modify the stepper shaft the most.

i am going to try to set my one up allot like that if i can.
 

I like the sideways mount - much better use of the available space on the Mendel carriage.

Adrian, you should do a quick pull test, and see how much force it can produce - we can have an extruder tractor pull. :)

Nophead, I've got about 5 kg of ABS and PLA through my old unsupported PTFE extruder, pic here:
http://gallery.me.com/wbortz#100008/Pinch%20wheel%20build&bgcolor=black

and another 2.5 kg of PLA through a newer PTFE extruder pictured here:
http://gallery.me.com/wbortz#100008/Extruder&bgcolor=black

The one failure I did have was from overheating due to the JB weld on the thermocouple failing.

Works well enough for me, making a 3rd one soon. I'd love an all stainless heater, but I haven't worked out how to make one without a lathe.
 

Aw, Adrian, that is SO fine! If we had brass pigmented PLA it would be positively Steampunk! I just LOVE it! :-D
 

Nophead and I are on the case of the fact that PTFE doesn't seem to have heard of the Copernican principle. It always works for us (and Wade), and never for him. Now - ours cost a lot more than his, so there may be a clue there. We're swapping samples to do a few tests.
 

Wade's design has a simple 7mm hex nut to transfer the torque, whereas you're using a wing nut. A wing nut is much larger, of course, and the larger gear ratio generates more torque (5:1 vs 2.4:1, roughly double the torque) but is the wing nut really needed? Plastic is tough stuff, and unless the motor is heating up and softening it, I'd think you could do this design with a hex nut and get about the same service life either way.

Given how much more difficult using a wing nut is, as they don't come in standard sizes, thus the file to force a fit.

Hmm, if you heated the wingnut instead of filing it down, that'd be quicker, simpler, and give a more solid connection. Might need a blowtorch to keep it hot while forcing it into the plastic though. How to do that while keeping it straight?
 

Wing nuts are pretty easy to get hold of.

I like the idea of heating it. If it was already on the shaft when you did this, it should stay straight; if it didn't, you could line it up using a square when the plastic was still soft anyway.
 

Wing nuts are pretty easy to get hold of.

I like the idea of heating it. If it was already on the shaft when you did this, it should stay straight; if it didn't, you could line it up using a square when the plastic was still soft anyway.