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3-D printing evolves, finds unique place in manufacturing

Despite drawbacks, 3-D printing will continue to revolutionize design, development and production of unique, low-volume complex parts.

Additive manufacturing -- the industrial version of 3-D printing -- offers an alternative manufacturing strategy that is being adopted in many different situations and markets. Like any other technology, it will provide new options and capabilities in some areas, but will be less useful in others.

Additive manufacturing differs from traditional manufacturing in that it forms the items being made by adding material through one of several mechanisms, the most well-known of which is to "print" successive layers of a liquid or gel form of the component material on top of each other to form a three-dimensional solid. Most traditional manufacturing consists of material removal, material forming or assembly. Another type of manufacturing, not a part of this discussion, uses chemical or physical processes to transform, rather than add or remove, raw material. Because additive manufacturing produces little or no "scrap" material, it is considered highly efficient and therefore very "green."

Initial success with 3-D printing is mostly with the use of plastics as the deposited material, although researchers are having some success with certain metals and other materials. However, the range of materials that can be used in 3-D printing is limited. Also, 3-D printing is not quick and it does not scale. It can take many hours to 3-D print a part of only modest size and complexity. And the cost of 3-D printers increases geometrically with increasing size (while speed may decrease and precision is harder to achieve). To produce parts in any volume requires rooms full of printers working 24/7.

3-D printing no threat to traditional volume manufacturing

Modern automated production processes can create large quantities of identical parts at high speed. 3-D printers produce single parts one at a time and the only scaling available is to install multiple printers to slowly produce parts simultaneously.

Despite its downsides, 3-D printing has and will continue to revolutionize design, development and production of unique, low-volume parts, particularly those with complex geometry.

CAD/CAM was a major advancement in the world of engineering and design. An assembly and its component parts can be specified in the design software, then analysis programs in the software can test strength, heat transfer properties, stress and strain characteristics, movement and operations, and much more. 3-D printing takes CAD/CAM to the next step by creating a physical prototype, albeit the prototype may not be in the material that the final product will use. Nevertheless, designers can touch and feel the prototype, mate it with other parts or objects in the real world, and learn more about the part or product before committing to expensive tooling and equipment needed for production. Waiting 10 or 12 hours for a 3-D printer to produce a prototype is certainly preferable to waiting days or weeks for the model shop to hand-craft a sample.

3-D printing is a great tool for producing one-off or small-quantity objects -- for example, replacement parts no longer in production, specialty products and art pieces (custom jewelry, for instance).

3-D printing finds its place in many arenas

In the medical arena, where custom-built replacement hip and knee joints are becoming common, 3-D printing seems particularly promising. Also showing great promise is research into using 3-D printers to produce other biological structures.

Printing parts with complex geometry can greatly reduce the number of individual parts (print the entire unit rather than assemble many parts) and result in a stronger and lighter part. GE has demonstrated the ability to use 3-D printers to produce complex jet engine parts (a 3-D rocket engine injector created by a 3-D printer has passed a major NASA test, "potentially heralding a new age of propulsion-system manufacturing," according to space agency officials).

Remote printing of service parts also is an area rife with potential. Think how handy it would be to have a 3-D printer in hard-to-access locations such as mines, drilling sites, or exploration sites in the far corners of the globe or in orbit on the International Space Station. Closer to home, 3-D printers could be the answer to an equipment manufacturer's need to maintain an inventory of low-volume replacement parts. With 3-D printing, a digital file of the needed part could be downloaded and printed by a dealer or service technician or, when printers become more commonplace, customers may be able to print the part themselves. More 3-D printing outlets are becoming available, offering a service much like having your cloud-based photos printed at Wal-Mart or your digital documents printed at FedEx-Kinko's.

These few examples highlight the chief appeal of 3-D printing today but, undoubtedly, more creative uses for the technology will emerge. Certainly, 3-D printing capabilities will improve as well, with the ability to print using more materials, faster and with more precision. But the scalability issue may ultimately limit 3-D printing's use in volume production.

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