A recent paper from CHI 2025 postulated a new method to make multi-material 3D prints recyclable. Finding places that will recycle 3D printed plastic is extremely difficult as it is, but when you combine two or more materials in one print, it becomes impossible. This is because many 3D printing materials are incompatible with each other, and mixing them together would create a lumpy, unprintable mess.
The method devised by researchers from the University of Colorado Boulder incorporates water-soluble seams and joiners directly into the design itself, placing them between different materials. They propose using PVA, which is already in use as a water-soluble support material. These PVA buffers need to be woven into the model to maintain strength and integrity. Once the printed model is worn out, it can be dunked in water to dissolve the PVA, and the different materials can be sorted for recycling.
