The push towards sustainability is everywhere, with manufacturers in particular feeling the pressure. One of the biggest impacts businesses can make is by switching to recycled materials wherever possible. Of course, the extent to which this is possible depends on the manufacturing processes involved.
So, what about 3D printing?
Can you 3D print with recycled materials?
The short answer is “Yes” but it comes with some qualifications. There are many types of recycled materials that can be 3D printed, including polymers such as PET, ABS, PLA and Nylon, metals such as aluminum, steel and titanium, and other materials such as wood and certain composites.
However, it’s important to select the right 3D printing process to use recycled materials effectively. For example, material extrusion can use filament made from recycled plastics and powder bed fusion processes such as selective laser sintering (SLS) can use powders made from recycled metals. On the other hand, while recyclable photopolymer resins have been theorized, none are currently commercially available.
What are the material properties of parts 3D printed with recycled materials?
As with any application, recycled materials may exhibit different mechanical properties compared to virgin materials due to degradation during recycling and previous use. In one test of recycled PLA, tensile strength, shear strength and hardness all decreased by 10.9%, 6.8% and 2.4%, respectively. Nevertheless, there are ways to mitigate material degradation. Surface finish may be similarly comprised, but – provided the part can withstand post-processing – once again there are ways to remedy the issue.
Can you 3D print with biodegradable plastic?
While not necessarily a recycled material, biodegradable plastics offer another avenue to sustainability in 3D printing. PLA is often cited as eco-friendly, though its biodegradability comes with some significant qualifiers. As with recycled materials, biodegradable plastics are more suited to some 3D printing processes than others: specifically, fused deposition modeling (FDM), stereolithography (SLA) and SLS. While there are obvious benefits to 3D printing with biodegradable plastics, it’s important to keep their limitations in mind. These include shelf life, temperature sensitivity and their mechanical properties compared to traditional plastics.
Is 3D printing environmentally friendly?
As with any complex process, the answer to this question is concordantly complicated. On the face of it, 3D printing has the potential to reduce carbon emissions directly through lower energy consumption (though this varies by process) and indirectly through shortened supply chains. Additive manufacturing (AM) processes also tend to generate less material waste than subtractive processes, such as machining, though some AM processes also emit volatile organic compounds (VOCs) or hazardous particulate matter.
Ultimately, whether or not a particular AM application is environmentally friendly (or at least friendlier than its subtractive equivalent) will depend on material selection, energy efficiency and waste management.