Computerworld – Richard Smith needed to build a wall-climbing robot for a customer — so he printed one.
Smith, director of Smith Engineering Gb Ltd., used a CAD program to design a 3D model of the WallRover, a dual-track roving robot with a spinning rotor in the chassis that creates enough suction to hold the device to a wall. He then sent the design file for each component to a 3D printer, which sliced the objects into sections less than 1/100th of an inch thick by printing it, one layer at a time, using molten ABS plastic as the “ink.”
As a 3D printer begins fabricating an object, each layer gets fused or glued to the previous one and the product gradually gets built up. Under the hood, 3D printers use a variety of different fabrication techniques, several of which are based on ink-jet technology, and can use many different types of “build” materials to print three-dimensional objects. (To learn more about the different types of 3D printers, check out our comparison chart.)
Before buying a 3D printer, Smith would send its designs to a service bureau for fabrication, and parts took three or four days to turn around. Had Smith used a service bureau for the WallRover project — which went through 22 design iterations — it would have taken six months to complete, Smith says.
Instead, Smith was able to get a final design and fully functional prototype to the client within two weeks.
And he did it using a consumer-grade 3D “plastic jet printer” that he built from a kit. The RapMan, from 3D Systems’ Bits From Bytes division, cost just $1,500. Smith spent another $180 for plastic filament — the “ink” consumed by the printer. “It saved five months of development time and somewhere in the neighborhood of $15,000 to $20,000 in models” that were created in-house instead of being sent to a service bureau, he says.
[Check out Rob Mitchell’s blog entry — 3D printing: A technology awaits its iPad moment.]
Smaller and cheaper
3D printing isn’t new. The manufacturing technique known today as 3D printing, also called additive manufacturing or direct digital manufacturing, has been used for rapid prototyping for decades. But over the last 24 months, prices have dropped to a level that makes it appealing to a wider audience.
The technology is more compact, particularly in the plastic jet-printing category. Cathy Lewis, vice president of global marketing at printer manufacturer 3D Systems Inc., says today’s models are “ideal” for personal use.
3D design gets easier
It’s relatively easy to use a free tool such as Google SketchUp to create simple objects for 3D printing. But for complex shapes and geometries, designers still reach for professional modeling tools like SolidWorks.
“Visualization software such as Google’s SketchUp provides a fast entry route” to 3D computer-aided design (CAD), says Nick Grace, manager of RapidformRCA, which acts as a 3D printing service bureau for students at the Royal College of Art in London and uses many different software design tools and 3D printer technologies.
But, he adds, “the shortcuts made by these tools are not allowed for in the 3D printer’s slicing routine.” For example, some software may not fully render elements of an object that aren’t needed from a particular viewpoint. That causes problems when the file is sent to the 3D printer. “We still regularly get unbuildable surface files or haphazardly constructed and translated data from files that render a perfectly coherent image,” he says. In other words, they look fine on screen but won’t print correctly.
Professional solid modeling tools do better job, but usually require specialized training and expertise. “The products today are pretty difficult to use,” admits Gonzalo Martinez, director of strategic research at Autodesk.
CAD software makers are addressing the 3D content creation challenge in three ways: By introducing easier-to-use solid modeling tools for 3D content creation, by offering libraries of 3D objects that give users a head start on a design and by using specialized software such as Autodesk’s 123D Photofly. This tool can combine a series of photographs of an object, taken from all sides, into a usable 3D model — a process known as photogrammetry.
Professional tool developers are working “to make complex operations more simple,” says Martinez. “Things that require training today you will be able to do with little training to create complex geometries.”
For example, Autodesk 123D, a free tool for CAD novices, is a much-simplified version of the vendor’s professional tools.
Other products, such as Rhino, a $995 program from McNeel, are edging closer to that middle ground between complexity and capability. “It is a high-end surface/mesh modeler, but has accessible controls and an excellent context-sensitive help with video clips,” says Grace.
“We are still some way off the point when a novice can draw, model and print without help from a specialist,” Grace says, “But that day will come.”
But creating a printable 3D object can be tricky. Designs created in a CAD program need to be “water tight,” or complete. “All surfaces have to be closed and lie on top of each other or you get holes in your part,” says Jon Cobb, vice president of marketing at 3D printer vendor Stratasys.
The design then needs to be exported to a standard file format 3D printers can use, most often the stereolithography (STL) format, originally developed by 3D Systems, that has become a de-facto industry standard.
Until recently, the quality of STL files produced by CAD programs wasn’t sufficient for 3D printing and required additional cleanup. But, Cobb says, that problem has largely gone away in professional solid modeling tools such as AutoCAD or SolidWorks. (Consumer-oriented design tools are a different story; see sidebar at left.)
Even so, Pete Basiliere, an analyst at Gartner who covers 3D printing, doesn’t see consumers using the technology for personal printing of unique, one-off household items. “What’s inhibiting consumer use is cost. It’s too expensive for most people.” Instead, he says, service bureaus may step in to fill those needs.