Mar. 17, 2015 | By Alec

While 3D printing technology is great for creating various plastic components in your own home, that is exactly also its largest downside: you’re filling your home, your trash and the world with even more plastic. Fortunately, filament extruders working with recycled plastics are being commercialized, while various grinders that can turn failed PLA or ABS experiments into new filament are also now available. This means that, theoretically, you can work with recycled plastics and even recycle them again for further 3D printing. It’s a great step in the right direction.

But wait a minute: everything around us is plastic! Why shouldn’t we be able to recycle our own trash for 3D printing purposes? That is exactly what a research team from Michigan Technological University, led by Joshua Pearce, is calling for in a new article that has recently been published in the journal Resources, Conservation and Recycling. And they’re absolutely right. Why shouldn’t we be able to recycle our own plastics in our own home and immediately 3D print it again? Even if the environment isn’t your biggest concern, Pearce and his team estimates that the filament prices can become as low as ten cents per kilogram through recycling (rather than the common $30).

But as Pearce explains in their publication, it’s not as simple as getting a recyclebot and just filling it with used plastic cutlery and empty milk jugs. The problem is that there are dozens and dozens of different types of polymers that are all being used for our daily products. Many of them don’t feature labels revealing what type of plastic has been used, or feature labels unsuited for 3D printed recycling. The US recycling system falls woefully short of the demands of 3D printing, as it only lists seven different codes in its labeling scheme. In comparison, China has a system that differentiates between 140 types of polymers.

‘We want to know about polymers the same way a chemist would,’ Pearce argues. ‘Currently, the most common 3-D printed plastics are grouped in the category seven polymers in the US,’ meaning that many 3D printable plastics are put in the same category as materials unsuited for printing. As an example, Pearce reveals that the distinctly different plastics used for water bottles and for milk jugs fall in the same US category. Pearce and his team therefore call for a paradigm shift in manufacturing and recycling standards that will enable 3D printing enthusiasts to recycle within the comfort of their own homes. ‘The centralized paradigm of both manufacturing and recycling is being challenged by the rise of 3D printing,’ Pearce says.

As part of their study, Pearce and his team have therefore developed a new resin code identification system that heavily borrows from China’s more extensive system. This new system focuses on 3D printable polymers and could be used as the basis for a new recycling system. ‘We also demonstrated how to incorporate recycling symbols into 3-D printed objects using open-source and parametric scripts for our new print codes,’ Pearce says. The scripts have already been released on Appropedia here, free for all the use. ‘Overall the results [of our study] showed that a far larger resin code identification system can be adopted in the U.S. to expand distributed recycling of polymers and manufacturing of plastic-based 3-D printed products,’ they write in the paper.

The idea is that even home users and commercial manufacturers that use 3D printing can include this scripts on their projects for easy recycling later on. While standard recycling labels are small raised areas somewhere on the bottom of a bottle, these labels can obviously be placed anywhere and woven into the design itself. Some of their examples even require you to shine a light through the bottom of a vase, or crack open a component, to find the code. This way, it doesn’t diminish the beauty of your 3D printed creations. ‘To make this actually happen, the coders for the slicing software need to make this an option,’ Pearce says. ‘So we’re sharing the source codes so they can incorporate them into their software for free, so everyone can use it.’

Recycling is crucial for 3D printing to become a sustainable and responsible technology, that can even do its part towards reducing the accumulation of trash on our planet. And adopting this manufacturing innovation – even in the relatively limited room of your desktop 3D printer – is the first step towards making 3D printing not just cost-effective and creative, but also environmentally friendly. You can find the improved recycling codes here. In the age of open source and at home development, we don’t have to wait for large industries to take the initiative.


Posted in 3D Printing Applications


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