It's been nearly seven years since 3D printers have hit the market but it's only this year that they are approaching "hit" status. Gaining in speed, affordability and ease of use, 3D printers are becoming more popular, allowing more companies to develop rapid prototyping capabilities in-house. These machines let CAD (computer aided design) users "print" three-dimensional concept models, making it easier for designers to share product designs with other departments, such as engineering and marketing.

According to consultant Terry Wohlers, president of Wohlers Associates, 3D printers are leading rapid prototyping (RP) machine sales. "Low-end machine sales soared to unprecedented heights, with 3D printers becoming the 'crown jewel' of the RP industry," he tells Plastics Technology Magazine. In fact, last year's worldwide sales of 3D printers, which are cheaper than other kinds of rapid prototyping machines, jumped 57.3% over 2002. In comparison, sales of other RP systems increased by only 2.6% in 2003.

Three-dimensional printing, which employs the ink-jet printer principle to deposit successive layers of material, is one of several rapid prototyping methods. Other processes include stereo lithography and selective laser sintering. Stereo lithography, the most commonly used method, constructs 3D models from liquid photosensitive polymers that set layer by layer in the presence of ultraviolet light. Meanwhile, selective laser sintering employs a laser beam to selectively melt and fuse powdered materials such as plastic or metal into solid objects. Stereo lithography provides good detail, accuracy and surface finish, while selective laser sintering produces parts that are tough and durable.

But nothing can beat 3D printing when it comes to low cost and speed. In fact, these systems can generally produce models in as little as one-tenth the time it takes other types of machines. While 3D printing cannot match the other methods when it comes to accuracy, its positive price/performance ratio is invigorating sales, says Wohlers. "For a lot of companies, spending well over $100,000 for the more sophisticated RP machines is simply not an option." For instance, stereo lithography machines range from $180,000 to $500,000. In comparison, companies can purchase a 3D printer for as low as $25,000 from Stratasys and Z Corp., two 3D printer makers. Most other 3D systems fall in the $35,000 to $55,000 price range.

While more sophisticated rapid prototyping machines produce tooling patterns and functional prototypes that could be rigorously tested, 3D printers work best for early design and visualization of models. "Most parts produced by low-end 3D printers are throwaway models that allow you to see things you would not be able to see as well on a computer with a CAD system," says Wohlers. "People want to hold the proposed design, study it, and get a good feel for its shape."

Additionally, prototypes created by 3D printers are good for communicating designs to toolmakers. "When you give the toolmaker a prototype in addition to your CAD drawing, it allows them to give a more accurate price quote—typically a more attractive one," John Cobb, vice president and general manager at Stratasys, tells Plastics Technology. "We have been told by users that you can save up to 6 to 8% of tooling costs with a prototype."

In short, for more and more companies, 3D printing is becoming the chosen route to in-house rapid prototyping capabilities. For a relatively modest investment, their design engineers can use these machines to increase collaboration, lower cost and shorten design cycles.

Source:

3D Printers Lead Growth of Rapid Prototyping
Lilli Manolis Sherman
Plastics Technology, August 2004
www.plasticstechnology.com/articles/200408cu3.html