[ Closed ] Filament Extruder - Convert pellets to filament (Page 42 of 58)

Most Excellent Puller Experiment!  What issues pop up as the amount of drop and span is decreased? Once you have a capstan, you almost want a constant tension take up reel like on the old tape recorders.  Could run the reel with a brushed DC motor and constant current supply.

Ian - agree with your statement about stiffness of the material being a factor on the scale we are operating on.  On the flip side, full size bridges use 1m diameter steel cables   Maybe we just need a 30m filament span, but then we'd have to name each machine.

Considering this more, maybe it is best to decouple the tasks of spooling and filament thickness control for the time being. Let's try to figure out how to do each one well, and then combine them if the opportunity presents itself. 

I don't have a Beta machine, so help me understand what might be the best "knobs" to turn to vary thickness.  Things like:
-Auger speed
-Auger torque
-Extruder temp
-Filament pull

How badly tuned must the Extruder Temp PID be to start messing up thickness?
What other things affect filament thickness during a run? (cat toy or bad hair day don't count)
What are the factors limiting increased feed rates? 

Wish I had a Beta to experiment on.  Wish I had more time!  This is cool stuff.

Dropping the filament into a loop on the way to the puller does decouple those tasks.  Variations in pulling or extrusion speed act on the loop rather than the diameter.  Changes in weight from the length of the loop are slight enough to not really effect diameter.  Pulling in a straight line from the extruder will directly affect diameter, but both the pull and the extrusion speed have to be constant, or at least in sync.

The loop doesn't have to be very long.  I've been experimenting with keeping everything on the table top by putting the winder on top of the extruder, setting the extruder on a shelf above the winder, and setting them both up on boxes.  I'm starting to think that mounting them both vertically is the simplest solution.   The filament will only go down, around, then up.  It doesn't have to go out, down, over, up and in.  More direction changes mean more opportunities for the filament to do odd things. 

I had it coming out of the extruder set up high, then curving down and back into the spooler which was lower than the extruder facing the same direction.  When the filament was anchored in the winder with the winder motor stopped, the stiff filament leading into the winder supported the filament coming out of the extuder above.  With the winder stopped, the sideways loop didn't drop toward the table, it kept going further and further to the side.  When I started the motor it again it jerked the filament a little and caused that mid-air loop to fall over sideways and cross itself.

II'm going to try some guide rollers and see if I can control the filament a little better to put the loop where I want it.

Peformed a overheat test today. Results as expected. Video here https://www.youtube.com/watch?v=VjMvEEtob64
It might be a good idea to make certain your thermocouple is engaged with the nozzle.
Filled house with smoke very quickly, no flames. The kapton tape did not even melt.

Here is my photo switch for the spooler - http://www.youtube.com/watch?v=uY7CcildG5o

I haven't been able to get the filament to loop through it.  It's been hard to get it into just the right position without getting a kink along the way that won't run through the clip.  I need to try extruding pointed down, or work out a PEEK nozzle to get the filament more stable coming out.

Cool setup!

3mm doesn't coil particularly well, unfortunately. Most of us here use 1.75mm.  You could try redrilling with a smaller bit, to try to end up nearer to the 2.85mm. The smaller the die, the more back pressure that can be built up, which it seems helps consistency. Other things that may help:

Increased airflow right at the die face (though this will increase diameter)
Overvolting motor. 15v is probably ok as long as the motor stays cool.

anynews when the kickstarter is gonna happen?

Congrats!

Nice project.  How are you determining the cost?  Is it with new parts + shipping, or with salvaged parts?

Even if that does include the cost of every single part, which I don't think it does, hand assembling those electronics will take a quite a while, welding/machining, as well as hand winding that heater. I'm also quite sure he's not including shipping from all the different vendors in that that price quote, either.

I don't think there was any welding in there that I could see.  It looked like it was mostly made out of Aluminum extrusions from the hardware store that were screwed or bolted together.  It looks like they were just cut to length and holes drilled.  The worm gear motor looks rugged.

Parts are from local shop and are new. Only the electric motor is old. To build this filament extruder, in this version, you need a lathe, a drill and a welding machine. Labor time was not calculated (6 hours). Electronics and heating element are homemade (1 day of work).

Thanks.
Which parts were welded?
Which operations required a Lathe?