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Public Radio's Environmental News Magazine (follow us on Google News)

3-D Printing is Green

Air Date: Week of

RepRap v.2 'Mendel' open-source FDM 3D printer. (Wikipedia)

3D printers are fairly small machines can make just about any metal or plastic object simply by following precise instructions from a computer. A recent study indicates that 3D printing is good for the environment, can save you money, and could be the basis of many new businesses. Michigan Technological University researcher Joshua Pearce tells Steve Curwood about his team’s unexpected findings.


CURWOOD: Back before the industrial revolution, if you needed some thing, you or someone else would make it by hand. Then along came the production line and big machines that could mass produce items quickly and cheaply. And now we are headed back to future with so-called 3D printing, where a fairly small machine can make just about any metal or plastic object simply by following precise instructions from a computer. A team at Michigan Technological University has studied the possible environmental and the financial benefits of 3D printing. Joshua Pearce led the research and explains the surprising results.

PEARCE: So a 3D printer is a device that allows you to manufacture three dimensional objects from long strings of spaghetti-like plastic. The hot end melts the plastic as it’s moving over a surface and it traces out just a two-dimensional image the same way a normal printer works. But what makes three-dimensional printers different is the head then moves up a fraction of a millimeter and repeats the pattern again. And by doing this again and again you develop layers of material until you make a three-dimensional object, and that can be extremely complex with intricate designs both on them and within them. There are high-end printers that can basically fabricate anything that you can think of, though the ones that we did the study on - and the ones I think are of interest to most consumers - are currently only able to print in plastic. The open-source models cost less than 500 dollars, and they can still make quite complex objects.

CURWOOD: So, tell us about your study. How did you figure the environmental impact of this?

PEARCE: We choose three relatively common everyday objects. The first was a child’s toy. It’s kind of an intricate stacking block. The second was a spout you use to water your garden. And the third was a juicer for making, say, orange juice in your kitchen. So these would be common products that would be readily available on the web and in most stores, and could be produced with the currently available low-end plastic 3-D printers that you could have in your home. And we did a complete life-cycle environmental analysis of them to determine what environmental impacts of producing objects were and compared them to conventional manufacturing.

CURWOOD: OK. And so what exactly did you find?

PEARCE: We found substantially reduced environmental impacts from making them at home. And this was somewhat surprising because one of the benefits of large-scale manufacturing is you can drive down the cost, and part of those costs, the production costs, comes from technical advantages. It makes a lot more sense to, say, melt a bunch of plastic in a large volume container, so you have a large volume in a small amount of surface area where the energy’s escaping. Yet, when you’re making things with a 3-D printer, your melt volume is very tiny. And so your surface area is larger and you’d expect more losses. We found the environmental impact was cut by about half, between 40 and 64 percent, depending on your settings and the type of object you were looking at.

CURWOOD: So wait a second. Why?

Researcher Joshua Pearce with laminated photovoltaic panels in his Michigan Tech lab (Michigan Technological University)

PEARCE: The savings come from a couple of places. One is the transportation. So we assumed that the objects were manufactured in China and shipped to the US. So you have that reduction in transportation embodied energy. If you make something at home, you don’t have to transport it anywhere. The biggest savings though came by something that the 3-D printers can do that normal manufacturing methods can’t, and that’s you can make intricate designs within the shape of the object. So you don’t have to have a completely solid object in order to have a structurally sound object. You can, for instance, make a honeycomb structure, within, say, the juicer, that you just couldn’t do by any other method.

CURWOOD: So you’d have the strength, but not the weight, not the materials.

PEARCE: That’s right. So you don’t use as much materials, then that directly kind of takes off the bottom line for both embodied energy and emissions that come from making the object.

CURWOOD: Now, some people listening to us might say, well, plastic being green is kind of counterintuitive.

PEARCE: Absolutely, so one of the environmentally friendly aspects of 3D printers is the most popular polymer that we use now, it’s polylactic acid, or PLA, and that’s an organic-based polymer that is derived from corn. So not only is it recyclable, it’s also compostable. As far as green materials go, it’s extremely green to begin with. I think as 3D printing catches on and more and more people begin using it, I think we’ll be doing direct recycling. Our group has created a recycle bot, which is basically a little tool that turns waste plastic into long strings of spaghetti that you then feed into the 3D printers. And that technology is much less developed than the 3D printers themselves, but it’s coming and it’s coming fast. Not only do we think we can expect people to 3D print things in their home, but I think we’ll start recycling in our homes as well, and radically reduce the environmental impact of things that we use on two fronts.

CURWOOD: Now, what about the cost of electricity? You have to use some power to run that 3D printer. So how economical is it, or even more environmentally sound to print one widget at a time, rather than making those widgets in a giant factory?

PEARCE: Our studies showed unquestionably using very conservative numbers for the energy use of these printers, and they basically don’t use any. It’s essentially the same amount of power draw that you’d have on your laptop. So these are not energy intensive beasts by any stretch of the imagination. To give you a feel for it, if we say the juicer, using less than a kilowatt hour to make it, and that’s a pretty large print. And so a kilowatt hour costs maybe on average in the United States 10 or 11 cents. You’re literally using only pennies of electricity to make most common objects. We’re already using less than half the energy to make an object as, say, a conventional manufacturing process.

CURWOOD: Your team also looked at different forms of energy, particularly solar power. So what about the use of photovoltaic cells to power 3D printers?

PEARCE: One of the unique aspects about 3D printers is it’s a distributed form of manufacturing, and so we started to think a little bit about what that meant in terms of energy use, and it couples very nicely to a form of distributed power generation. And our group has already developed two separate types of solar powered 3D printers. One was for schools in the developing world, and the other one can fit literally into a suitcase. And so it actually couples very nicely. So a small module produces enough solar power to power these RepRap 3D printers, and when you look at the environmental impacts of that, it annihilates what you can do conventionally. It’s a technology that is primed to use a distributive sort of form of generation like solar photovoltaics that turns sunlight directly into electricity.

PEARCE: It’s probably pretty obvious to you, but to someone listening to us it may not be obvious why they would want to have a 3D printer in their home.

CURWOOD: It will depend very much on the type of person you are. So we’re scientists so a lot of what of what we use our 3D printers for is making scientific equipment. And we’ve cut the cost of scientific equipment down by like 99 percent. For us, that’s a very clear no-brainer. For the average homeowner, it’ll be for doing things that they want customized for themselves first, and so it might be medical applications, it might be things that, if they’re really into particular television show or something and they want a customized toy that is not available, they can justify the cost of the printer for making something special for themselves.

CURWOOD: What will be the impact on jobs with 3D printers?

PEARCE: I think we’re going to see both a lot of job destruction and a lot of job creation. On the destruction side, if your business model is currently based on doing mass manufacturing of polymer based products and selling them for a high markup, you’re in trouble because, I think, in the very near future, people, if they don’t have 3D printers in their own homes, they’ll have access to them at, say, a local 3D print shop, and they’ll be able to make those things for themselves. On the other hand, there’s an enormous opportunity for small-scale entrepreneurship, where if you own a 3D printer, you can start to provide enormous value for people in your local community by printing out the things they need and want. Because you can produce it so much less expensively than is currently available, there’s a huge amount of potential for profit.

CURWOOD: Joshua Pearce is a Professor Michigan Technological University where he heads up the Open Sustainability Tech Lab. Thanks so much for sharing your time with us today.

PEARCE: Thank you. It's been a pleasure.



In Sustainable Chemistry & Engineering, ACS Publications, “Environmental Life Cycle Analysis of Distributed Three-Dimensional Printing and Conventional Manufacturing of Polymer Products,” by Megan Kreiger and Joshua M. Pearce

Pearce Research Group, Michigan Tech’s Lab in Open Sustainability Technology

Printers for Pearce: An Interview with 3D Printers for Peace’s Dr. Joshua Pearce

“Getting Started in 3D Printing,” by Lee H. Goldberg


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