3D printers produce a large amount of plastic waste which hopefully the new generation of multi head printers like the H2C will help solve.
But many users rely on single head machines for multi colour printing which generates a LOT of purging waste particularly from commercial printing farms.
Is there some way 3D Printing waste can be recycled to minimise negative environmental impacts?
Technically yes, practically less so.
The second one is expensive and it can suffer from contamination between different filament types. It can also suffer from issues while trying to maintain a constant thickness.
Filament shredder.
Some people buy silicone molds and make skulls and things like that. I thought about making some colorful wall tiles to hang on my printer room walls, but then discovered a better use for the mold i purchased, storing freshly removed hot nozzles. Its one of my must have tools now and always besides the printer. 
A few ideas here - I think melting the waste into plastic sheets has a fair bit of potential - I haven’t done much with this for a while - but I have plenty of waste PLA built up for when I get back to it.
The main challenge isn’t the recycling itself, but avoiding the mixing of different filament types. My waste bin usually contains a blend of nearly all the materials I print with, and sorting them out without contamination would be a real pain.
Back in the day, I built a homemade filament maker that shredded PET bottles and extruded them into printable PET filament — the results were fairly decent, but these days it’s simply not worth the effort for me anymore.
Check out these systems:
There is a US company in St. Louis that deals exclusively in recycled filament. They’ll accept print waste, with a few minor sorting guidelines (separate PETG from PLA, etc.) Google “Printerior Recycling” and you’ll find their info page.
They’ll give you discounts on their filament based on the amount you send them, so it could potentially be useful over time even if you do have to pay to ship your waste. I’ve sent them almost 5 KG of PLA waste but I’ve yet to try their filaments. I’m just happy to send it somewhere where it will go to use.
I store the waste in the form of arts. I haved used some in place of packing peanuts and probably will keep using them that way. It’s reuse, not recycle.
Just like recycling other general household plastics, recycling filament waste will have challenges. Dumping them into the regular cycle pins won’t work. Shipping them out to a few specialized recycling centers, as suggested by the post above, has its own cons. Shipping has a large carbon footprint. In order to save a box of waste, packaging and shipping create waste and carbon emission along the way.
Yes. We do use silicone molds and recycle 100% of our purged filament.
Pretend it is muesli.
What kind of molds? I have been struggling to find or even create a mold myself that’s functional
Great point! Plastic waste is definitely a big concern in 3D printing, especially with single-head multi-color machines that require a lot of purging.
One approach is to reuse or recycle failed prints and purge material, and this is something we often consider when doing rapid prototyping. By carefully planning prints and reprocessing waste filament, it’s possible to minimise environmental impact while still producing accurate, multi-color parts.
Old post I know, but a competitor has now built a grinder and filament maker, though you have to add some virgin filament for integrity, I’m very torn on getting one or not. Does mean less waste, and apparently you can even use plastic bottles like water bottles.
What are you waiting for ?
I already bought the Sunlu’s jointer. Now it takes up space in my closet as an eternal testament to how stupid I am 
just 45€ fortunately
