Does anyone know what the process is to actually make PLA or ABS 3mm/1.75mm filament from raw PLA/ABS plastic? What machinery would a company use to convert its raw plastics to filament that’s ready for sale to the public? Something like the filabot, but for industrial purposes.
I appreciate your insights!
I would expect that it is a standard extrusion. Or if you want to look at it a little differently a really big print head with an integrated heater and chiller so the plastic is fully solidified by the time it comes out.
Wasn’t there a kickstarter a year or so ago called “Filabot” or some such that looked at making filament from recycling your own plastic?
A plastic extruder, water bath, and a puller. Stratasys has a patent for how to make it best. In the patent there is a schematic of a two piece die that shapes half of the circle at a time.
Thanks for the responses, folks. You guys rock!
The filabot looks cool, and so does the ramen (http://www.makibox.com/details/product/ramen_kit) in concept, but the paying public can’t actually get either, yet. They’re both still in development. Also, they produce filament at hobbyist volumes, I would imagine.
I’m interested in surveying the machinery to produce filaments at industrial weights - 10 to 100 kg per hour. Let me know if you’ve got any leads!
Come to think of it, if folks are aware of companies that perform that operation as a service, I would love to hear about that, too.
In addition to extrusion, you’ll do some basic finishing operations such as sending it through some rollers to make it as circular as possible. Temperature control at every stage is critical.
You need to prevent any gasses or moisture from being allowed into the plastic as you form it, too, which makes the apparatus still a bit more complex compared to a regular old hot end.
The challenge in making filament is largely QC. The tighter the tolerance, the more the filament you produce is worth, which is why it’s still best to get the filament from a professional manufacturer at this point, and will probably remain so for quite a while.
Rollers don’t shape the filament, it’s solid by the time it reaches that point. If there are notches in the rollers, it’s probably to keep the filament from getting flattened. Places like Village Plastics will probably do runs for you, but I don’t know what the minimums would be like.
In Germany that would be Orbitech or Putsch Plastik afaik
http://3dprinterfilaments.com have an excellent selection of filaments and their elastic filaments are very cool.
The ideas of quality control and finishing seem pretty reasonable. Conversely, I could imagine a reliable process that doesn’t require them - but I’m not a professional plastics guy. Do you have any links or documentation that describe that process, @Miles_Wilford ?
We use a one-piece die in the big extruders, and a long, long air and water cooling zone - about 10 metres. This also contains an employee with a micrometer. We carefully control the heating and cooling so the plastic remains perfectly straight and smooth. Finally, we pass it all through a sizing die that normally will not touch the plastic. If a lump somehow gets through, it will block the die and halt our run.
Our machines used to make knitting needles - very high quality. We do custom runs of 300m or more if you need it.