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3-D Printing: Cars, Houses, Guns, and More

August 2015

I don't (currently) have a need for a pistol, but if I did, I could print one. I could download the 3-D graphics to my computer, print the parts on a 3-D printer, and then assemble a working plastic gun. In fact, the most downloaded 3-D model on the GrabCAD website is for a Colt 1911-A1 Model Government Pistol. The government isn't too happy about this.

The more common uses of 3-D printing, though, are much more benign. Such as the child who was born with an underdeveloped trachea, causing serious medical problems. The doctors treating him used 3-D printing to print a small splint of biocompatible material based on a model created from a CT scan. They successfully implanted the splint, which supported the infant's trachea and allowed it to grow. Eventually new cells grew around the splint, and the splint itself gradually dissolved, leaving the boy with a normal trachea.

3-D printing is now being used for an amazingly wide range of purposes, and the cost of printers has dropped dramatically. You may yourself find a use for one in the near future.

The basic principle is simple. You're likely familiar with how an inkjet printer lays down a thin film of ink onto paper. A 3-D printer is like that, but instead of laying down a thin film, it continues to add more and more layers of material, until you have a three-dimensional object.

These printers use a variety of materials: plastics and polymers, of course, but also ceramics, wax, a range of metal and alloys, clay, silicone, porcelain, plaster, and more. They originally cost tens of thousands of dollars, with the first sub-$10,000 printer coming on the market in 2007. You can now buy a 3-D printer for as little as $250 (though the cheapest ones often come as kits that you need to assemble). Better quality 3-D printers are often in the $2,000 range, plus according to one review the more expensive ones can be easier to use.

But you don't need to buy one in order to do some 3-D printing, with establishments such as Staples making 3-D printers available for use. In addition, many communities are now setting up makerspaces, where people can go to access a variety of tools, everything from sewing machines to power saws. The workshop in the Sustainable Living department on MUM campus in Fairfield is being made available as a makerspace until another such space can be set up in the community. I'm hopeful that it will include a 3-D printer.

3-D printing is now being used to make cars, houses, prosthetics, eyeglasses, jewelry, smartphone cases, tableware, cremation urns, and acoustic guitars. Of course, these printers are extremely useful for manufacturing custom parts, including replacement car parts. Other frequently downloaded models on GrabCAD include models for a bike frame, a human skeleton, an Iron Man helmet, and a robotic hand. You can even download models for a kit with parts for a 3-D printer.

If you're handy with computer-assisted design (CAD), you can make your own 3-D models to print. Or you can download models and tweak them to your taste.

3-D printing is now also commonly called "additive manufacturing." It's said to be more efficient than previous techniques for machining parts because it uses only the amount of material that's needed. The conventional approach to machining parts has typically involved milling and boring and cutting, all of which wastes material. The conventional approach is now increasingly being referred to as "subtractive manufacturing."

Okay, I get that I can make a cup or an iPad case or a car part, but a whole house? Or even an office building (as Dubai is doing)? Yep, Dutch architects have used a giant 3-D printer to build a house. The parts of the house are made from a bio-plastic material that is 75% vegetable oil reinforced with microfibers. Not only is it less wasteful and more environmentally friendly than traditional homes, but also the materials can be melted down and recycled. Or if you want to move to a new location, you simply disassemble your house and reassemble it in the new location.

Also, a Chinese company has printed a working electric car at a total cost of $1,770. Top speed: 25mph. And Local Motors, an American company, has a car called the Strati that can go 40 mph — and that can be printed in just 44 hours. They're currently setting up microfactories around the world.

I think we're witnessing yet one more computer-based revolution: manufacturing is now available to everyone.

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© 2015 by Jim Karpen, Ph.D.

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