Will it ever be possible to flip on a rapid prototyping machine and pop out a model with 100 percent of the physical properties of the finished product?
Probably not, but new materials can get pretty close, said Tom Mueller, a pioneer in the RP field. If you can match a few key properties with a model, you can skip the step of making a rapid mold and dramatically cut the time to develop new products, he said.
Mueller, co-owner of Express Pattern Inc. in Buffalo Grove, Ill., outlined advances in rapid prototyping materials March 22 at the Charlotte conference of the Structural Plastics Division of the Society of the Plastics Industry Inc.
The goal should not be to duplicate the finished part exactly, but to create a ``functional model'' using rapid prototyping, Mueller said.
Mueller bought one of the first stereolithography machines in the late 1980s at Baxter Healthcare Corp., where he was manager of computer-aided engineering.
``The early materials were very brittle. In fact, if you looked at it wrong, it would break,'' he said with a chuckle.
Now there are some good new materials. But some limitations remain. For example, he said, most RP models are not good for running impact tests. To get a 100 percent property match, you still have to make a rapid mold, then run some limited-production parts.
But Mueller said just matching, or coming close, on certain very important properties could be good enough. The degree of closeness depends on the physical demands of each specific application.
Product designers first have to determine how close they need to come for properties such as stiffness, flexural modulus, impact and coefficient of thermal expansion, then select the proper rapid prototyping material.
Another industry expert, RP consultant Terry Wohlers, spoke March 24 in Charlotte at a conference sponsored by MoldMaking Technology Magazine.
Wohlers documented the changing role of service providers, small companies that do contract prototyping for original equipment manufacturers. A few years ago, OEMs used to outsource all of their RP work to service providers, but OEMs now are buying low-priced, three-dimensional printers. Some such printers now sell for about $30,000, and Wohlers said prices will continue to drop.
Too much capacity is another problem. ``[Service providers] were buying machines like there was no tomorrow, and it led to a big overcapacity,'' he said.
In 1995, 25 percent of all rapid prototyping machines were running at service providers. Today that figure has declined to just 9 percent.
But Wohlers said OEMs still outsource work in the later stages of prototyping. Also, service providers are beefing up expertise in the newer RP area of metals, to do rapid mold making, he said.
Wohlers, who runs Wohlers Associates of Fort Collins, Colo., will issue his RP report for 2004 at the Rapid Prototyping Manufacturing 2004 show, set for May 10-13 in Dearborn, Mich.
He treated his Charlotte audience to some exotic examples of using the technology to do direct manufacturing - turning out highly specialized, finished products. No models. No tooling.
Devotees say that could lead to the nirvana of ``mass customization,'' where every part is made just for you.
Hearing-aid makers are adopting the technology to make the devices better fitting for each user. Wohlers said RP also can be used to make a model of a hand, for example, or an artificial joint.
``The medical business is a sleeping giant, and it's going to be enormous,'' he said.
An Italian company, Treviso Tecnologia, uses rapid prototyping to turn out the frames for limited-edition sunglasses.
In the Netherlands, Amsterdam-based Freedom of Creation is turning out arty lampshades in small quantities. The avant-garde firm even is experimenting with clothing - with the ``cloth'' resembling chain mail or a mesh formed by a series of spirals.