How exactly does 3D printing work?

A Dutch architect recently announced plans to construct a house using 3D printing, a technology that has been around for decades but has only entered the public consciousness in the last few years.

Janjapp Ruijssenaars, who works with the Amsterdam-based architecture studio Universe Architecture, recently announced his plans for Landscape House, a looping infinity building that he expects will be completed in 2014, according to the Guardian.

Expected to cost between $5 million and $7 million, the building will be made from 3D-printed pieces.

Frequently portrayed as a seemingly magical process, 3D printing — also called additive manufacturing — involves creating a solid object by layering thin slices of material including plastic, metal and ceramic.

"It’s been in use for industrial contexts for at least 20 years," says Matt Ratto, assistant professor at the University of Toronto and director of the information faculty’s Critical Making Lab.

However, 3D printing has caught the public eye over the last few years as the technology has become more refined, not to mention cheaper.

Some of the proposed uses have drawn widespread attention in the media, from the ability to manufacture gun parts at home to the creation of edible entrees from pureed foods.

Anyone hoping for a Star Trek-type "replicator" able to generate myriad objects of varying complexity will likely be disappointed, as the technology is typically used to test the fit and functionality of prototype models or pieces in manufacturing and design projects.

How it works

There are several types of 3D printers. They may use different materials, but all involve the same basic approach for "printing" an object: spraying or otherwise transferring a substance in multiple layers onto a building surface, beginning with the bottom layer.

Before the printing can occur, a person must first create a 3D image of the item they want printed using a computer-assisted design (CAD) software program. That object is then sliced into hundreds or thousands of horizontal layers, which are placed one on top of the other until the completed object emerges.

One type, called selective laser sintering, involves heating and solidifying granular material with a laser in a specific pattern for each slice before repeating over and over again with new layers; this technique could be used in creating figurines, for example. Another uses UV light to cure layers of resin. Others deposit material much like an automated glue gun.

Ruijssenaars, the Dutch architect who intends to 3D print a house, plans to use a large machine that deposits sand and a binding agent in layers roughly five to 10 millimetres thick to create six-by-nine-metre sections of a stone-like material. Those blocks will then be used to construct the home.

Ratto said the theory behind building a house out of 3D-printed blocks is sound, although it has never been attempted on such a scale. The machine that Ruijssenaars would use is essentially a larger version of the printers already being used.

"I don’t think it’s a hard thing to do. The hard thing is to build a machine that would be cost-effective and reliable," Ratto said.

The technology could also be used in the future to create customized concrete blocks, a research area that is currently being explored in the U.K., Ratto said.

‘From industry to consumer curiosity’

Most of the 3D printers available, however, are smaller and not meant to build houses.

Reuben Menezes, marketing manager at 3D Printers Canada, says his company sells a variety of machines with differently sized building areas. The smallest measures 13 x 13 centimetres with a height of 13 centimetres, while the largest is 90 x 60 centimetres and 90 centimetres in height.

Although entry-level hobbyist machines can be found in the $1,000 range, the company's heavy-duty 3D printers range in price from $9,000 to upwards of $600,000.

Menezes says 3D Printing Canada sells primarily to academic institutions and companies with research and development arms for the purpose of testing prototype parts.

There are smaller and cheaper models available for eager hobbyists, some for less than $1,000, which are often used to design toys or gadgets.  

Annette Kalbhenn, sales and marketing manager at 3D Prototype Designs in Toronto, says her company has been using 3D printing for rapid prototyping – creating short runs of test pieces for manufacturing processes – for about 15 years.

"I think the biggest trend that I’ve noticed is that there is more public awareness," she said. "It’s kind of flipping from industry to consumer curiosity."

Despite its growing popularity, Kalbhenn says some people have misconceptions about 3D printing.

"That anyone can do it and that it’s easy and it’s inexpensive and instead of going to the Volvo parts replacement you can just make it yourself for two dollars," Kalbhenn said, citing some of the misconceptions.

Some people are unaware, Kalbhenn said, that you can’t really print anything without the CAD file containing a plethora of data about the object’s dimensions.

Technology has its limitations

While there are websites offering a variety of downloadable designs, Ratto says most of the people using the CAD software are trained professionals, not the average hobbyist.

That creates major obstacles for a layperson wanting, for example, to 3D print a small piece of a closet door that is likely available at a reasonable cost in a traditional store, Ratto says.

Another limitation is that the printers create an object out of only one material when most consumer goods are made of many.

Ratto said researchers are looking at ways to solve that by creating devices that print a number of different materials. For instance, a machine could combine plastic and conductive material to create electronics, including cellphones.

Some business observers are pinning high hopes on 3D printing, believing that the technology could return a level of small-scale, custom manufacturing back to North America, Ratto said.

"I think that’s one of the claims and I don’t think it’s impossible," he says "I think it’s an interesting possibility and one that is potentially feasible."