|Winder box with Filastruder on top|
To take advantage of this, a number of solutions exist for making one's own filament, including the Filastruder, a kit I received a prior Christmas. Cleverly designed from largely ordinary hardware, the device extrudes filament by squeezing plastic pellets with an auger bit down a heated length pipe and out a small nozzle.
For a more convenient system, I decided to try making a simple filament winder that could take up the filament as it is produced, keeping it neat and consistent. While a commercial winder kit exists, I could justify neither the cost nor large wall hanging space it requires when set-up. Instead, I chose to make one of my own design; one that didn't require the same finicky electronics. It would also be a challenge which added to the fun. Lastly, I came up with the idea of building it into a handy portable case that could house both itself and the Filastruder, keeping them free of dust and out of the way when not in use.
Other winders use linear sensors, but they require a microprocessor and more complexity, which I hoped to avoid. After trying mercury switches and considering magnetic reed switches and other sensors,
I settled on a lightweight 3D-printed "see-saw" rocker that I weighted down slightly on one side. The filament moves in a loop down the left side of the box, across the bottom, and up the right side. When the filament develops too much slack, the bottom of the loop pushes down on a curved acetate surface glued to one side of the rocker. This lifts up the other side, raising a shutter that exposes a CDS-cell light detector to a single LED light source.
To evenly guide the filament onto the spool, the filament passes through a short length of tubing mounted onto a hinge. As the hinge moves, the filament comes out at a different place on the reel, keeping it from bunching up in one place.
The hinge, in turn, is linked to a carriage, that moves up and down along a worm gear (threaded rod) driven by a second gear motor. Two momentary limit switches keep the carriage from moving too far in either direction. They simply switch on and off a DPDT latching relay, wired in a way (one on, one off) so that the motor reverses direction when either switch is hit.
After my initial tests, I also added a small, spring loaded clamp to keep the filament under tension. This was needed to keep the filament tight on the reel.
Here is the completed winder case. When in storage, the Filastruder fits neatly inside with hanging space for an empty or full filament spool.
I was surprised how well it worked right off the bat. The rocker assembly tends to stay right on the edge between on and off, moving ever so slightly to periodically activate the take-up motor. The movements are so small that the filament path moves very little, leading to the most consistent filament than I've ever made before.
I've already successfully used it to create two one-pound (half-size) spools. I'll still probably buy some filament, particularly for special colors and specialty plastics. When I need simple black or white filament, however (the colors I use the most), from now on I'll probably just make my own.