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."
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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.
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.
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.)