3D printing is fabulous by itself, but many enthusiasts out there concentrate their efforts on recycling and home filament making. One of them is Stefan from the channel CNC Kitchen, and this time he decided to tackle something that honestly shouldn't exist: disposable cutlery. His tests include processing cutlery with various quality levels, and most importantly, dirty plastic.
Disposable cutlery is… a horror. I can understand the need for a spoon when eating ice cream or other desserts, but if knives don't cut and forks break with minimal effort, what's the point? Single-use plastics have been banned in many parts of the world, however, it's not hard to find exceptions, and online sales platforms continue to sell them.
But there is another possibility: that they stop being “single-use” through direct recycling, courtesy of 3D printing and home filament production. Stefan from the channel CNC Kitchen explored that possibility recently, and with the exact dose of tweaking, his results were excellent.
How to recycle disposable cutlery to create filament
Of course, Stefan has a shredder and an extrusion system, but machines aren't magic, and the material requires prior processing. The main advantage is that cutlery is made of PLA. Under the right conditions, PLA is biodegradable, however, ideally it shouldn't end up in a landfill in the first place (the process takes 80 years on average). All of Stefan's equipment is compatible with PLA, so the chain is shred-dry-extrude.
The first round of black PLA created a filament that was too brittle, but by adjusting the temperature and adding virgin transparent PLA (in a 50/50 ratio), the problem disappeared. The deficit in filament diameter can be compensated in the printer by increasing the flow.
In his next test, Stefan discovered that there are big quality differences between cutlery, and beyond color contamination, the filament he got in the second round was very good. The most important part was left for the end: recycling cutlery that was already used. Stefan prepared a marinara sauce, dirtied the cutlery with it, let the “mixture” rest overnight, and proceeded to wash/dry/shred that same plastic. Beyond a slight herb smell in the PLA, the filament responded wonderfully with only 20% virgin PLA, and just a few red pellets to inject color.
In summary, the process is slow and requires manual intervention... but it works.
