[ Closed ] Filament Extruder - Convert pellets to filament (Page 9 of 58)

Sure - even if they're optical.

The problem is that the allowable tension on the hot filament is nearly zero. You can blow on it and deform it for the first inch or two out of the hotend. That limits you to sensors - I don't think a clutch could be that sensitive.

I have an idea I'm pretty confident in, but need to get these next batch of betas out the door before I go back to experimenting. Speaking of which:

I came home from vacation to find that the PID controllers are not yet here. I expected them to be delivered over the holidays, but I guess USPS got behind in their deliveries. I'll do all the other work today - shipping labels, packing boxes, but they can't go out until the PID controllers get here. Sorry guys.

I like Lyman's setup where there are motorized pinch rollers before the spool.  You can set the speed that gives you the right diameter, and the tension stays constant.  Then you have a lot more leeway in how you handle the filament on the other side.  You would then be able to use the mechanical switches to coordinate the spooling and the pinch roller.

The best bet for that would be something routed out in a material that is resistant to acetone, or printed and then coated in some kind of resist.  The latter would be easiest for me, but I don't know what would work as a resist.

If I'm picturing this correctly, it assumes the extrusion rate is constant. I'm not sure that's the case, though I don't any data for/against.

I was thinking something along these lines, if the pull force out of the extruder is that touchy you could go with a start and stop trigger so you maintain a consistent loop, then you don't have to match speed the coiler would just adjust itself to whatever speed you were getting.   Hopefully this conveys the idea, I got lazy and just sketched in autocad. 

Yeah, and you'd need to come up with a guide that moves back and forth along the spool so you don't have all the filament on one side of the spool, unless you're doing only 1" spools or something then you'd likely be fine without it.

Does cooling need to be done right at the exit of the tip?  For example would looping it into a meat loaf tin full of water work or is it already deformed by that point? 

The only other thing I can think of without touching it would be to take copper pipes like you had in your original vapor bath, pump ice water through in a loop and have a tight coil of maybe 6 or 10 wraps that the filament passes through coming out of the extruder, should super cool it right as it comes out and maybe eliminate the stretching / deformation?  Let me know if that makes sense, otherwise I break out the autocad again.  (Don't make me do it) haha

Beta v2 is finished! I just fired it up.

Changes:

• Got rid of the hotend/coldend flanges, since quality control was not very good on them, and they were getting misaligned.

• Uses hopper v2 and hopperfunnelv2

• I shortened the motor shaft, this is definitely optional

• Uses a hex socket instead of setscrew shaft coupling. Hopefully this will grip the auger better

• Did away with the threaded rod. This is much faster to assemble - I can do one in under an hour now.

I'm pretty sure the auger was turning the whole nipple, and the hopper went along for the ride. I didn't want to spill pellets, so I put a screw in, in case the nipple tightened some more. It seems to have stabilized now.

Post the STL, if you don't mind!