A spool based 3D FDM printer requires a plastic filament for 3D printing. This filament would act as a toner cartridge. The plastic which comes pre-packaged is expensive and therefore to combat this high cost, you can make your own filament extruders like the Filabot or the Filstruder and the plastic pellets.
Pa Lemur undertook an Instructables project, used recycled plastic to make his 3D printer part cycling Grinder. Moreover, this device was made using the basic tools which Pa Lemur possessed and it took 40 hours to complete the project which was carried out in the garage of his house.
This is how the grinder works- It operates like a pair of scissors with a forward cutting front. Bolts and nuts make the tool sturdy and stiff. Though the process of recycling plastic from the grinder is a tedious and time-consuming job which involves huge amounts of time, it is a big cost saver.
The cost involved in recycling freely available plastic into a form that can be used as a spool filament is negligible and therefore, worth the hard labor.
The project requires small tasks like gluing, rotary tools, abrasive wheels, metal part filing, cutting and a drill that can plow through the metal, are required elements to construct the device.
When the cutting process is complete, the assembling process is initiated. It involves stacking, threading, and drilling, these processes are repeated until all the blades are well-fitted and the handmade 3D Printer part recycling grinder is ready for use.
The Instructables prototype is capable of cutting up parts up to 1/4” thick in solid PLA wall but it is difficult to cut tough materials like polycarbonate.
Also, the blade for chopping things up is about 0.5” square opening which allows very little pieces can go into the grinder. Some PETE plastic too got stuck in the blades sometimes.
In spite of the drawbacks, the toil and the effort by someone to undertake this project are commendable and worth mentioning.