Recycling symbol. Source:  Igor Shikov/
Recycling symbol. Source: Igor Shikov/

3D printing is a splendid new technology, but it does bring up questions of sustainability, reuse, and recyclability. ABS and PLA plastic are common materials used in 3D printing as well as paper and metal. Let us explore some of the recycling options open to us.

What is PLA Plastic?

Polylactic Acid (PLA) plastic is a thermoplastic polymer that softens when heated and hardens when cooled. It is made from renewable resources, such as cornstarch and sugarcane.

Recycling PLA Plastic

 PLA plastic is biodegradable under the right circumstances. However, these circumstances are very specific and PLA cannot be composted in your typical compost heap.  PLA needs to be recycled at a facility where plant scraps are turned into fertilizer by microbes. The compost heap must reach 140 degrees for 10 days in order to compost the PLA plastic material.

PLA plastic is recycling code #2.

What is ABS Plastic?

ABS plastic is a thermoplastic polymer that softens when heated and hardens when cooled. Nitrile chains bind together, which makes ABS plastic stronger than pure polystyrene. Styrene gives ABS a shiny surface and butadiene provides resilience.

Recycling ABS Plastic

There are some options to use recycled ABS plastic, such as milk jugs, and turn it into filament for 3D printing. Recycling machines, such as RecycleBot, are designed to convert shredded milk jugs into filament by melting the plastic and then extruding the melted plastic through a nozzle.

Another option is to use machines, such as ExtrusionBot, that use plastic ABS or PLA plastic pellets to create filament at a cheaper cost, which if used correctly, can prevent waste. This machine allows you to create filament as you need it and as much as you need it, so that companies will not have to keep a large stock of filament on hand.

ABS plastic is recycling code #9 or #ABS.

Other Methods of Recycling Plastic

Scientists Miranda Wang and Jeanny Yao, are also working on breaking down plastic phthalates with bacteria. Phthalates are a plasticizer harmful to health and can take hundreds or even thousands of years to biodegrade.

Watch the TED Talk

Recycling Paper in 3D Printing

Some printers, such as the Mcor, uses ordinary office paper to print 3D parts. The Mcor can use recycled paper to print parts, the paper support material is reusable and the 3D parts are 100% recyclable.

Paper is recycling codes #20 C PAP, #21 PAP, #22 PAP, or #23 PBD.

Recycling Metals: Stainless Steel, Brass, and Sterling Silver in 3D Printing

3D parts made of stainless steel are not recyclable. Sterling silver and brass 3D printed parts can be taken to scrap metal recyclers to possibly sell. Your local scrap metal recycler will be able to tell you if they will accept 3D printed metal parts for recycling.

Recycling Ceramics in 3D Printing:

3D printed parts created out of ceramic materials are recyclable. Contact your local recycling program to find out if they accept ceramics. Ceramic parts can be crushed and reused as drainage rocks for flower pots or used in ceramic mosaics.

Recycling Sandstone in 3D Printing

3D printed parts created out of sandstone-like material are not recyclable