Sculptor adopts rapid prototyping technology

The largest-ever sculpture produced by rapid prototyping (RP) was unveiled by Helisys Inc., Torrance, Calif., in September at the International Manufacturing Technology Show (IMTS 98). IMPS is held in Chicago, Ill., and is sponsored by the Assn. for Manufacturing Technology, McLean, Va.

The 1.8 m (6 ft) tall sculpture -- titled "Chakra Seuss" -- was created by Michael Rees and built by Helisys using its Laminated Object Manufacturing (LOM) technology. The work has an estimated value of $35,000.

There are five basic steps in the patented RP method:
CAD data is entered into the LOM system's process control computer directly from your network.
Special software slices the geometry into many layers in the vertical z-axis.
The machine's CO2 laser cuts a cross-sectional outline in the top layer of the RP material (a special paper or plastic) and crosshatches excess material.
A new layer is bonded to the previously cut layer and a new cross section is created and cut as before.
Once all layers have been laminated, cut, and crosshatched, excess material is removed to expose the finished part.

"Chakra Seuss" was built in 186 hours. "If I had molded each individual part by hand, it would have taken years," states Rees.

Another use: A Helisys LOM system has been hooked up to the Internet at the Tele-Manufacturing (TMF) project at the University of California's San Diego Supercomputer Center (SDSC). Researchers access the system via the Net and use it to produce small solid models from a variety of 3-D geometry data sets. In all the TMF applications to date, the models have helped identify features not detected in 3-D computer graphics displays. Examples: docking sites on proteins, silt mounds in San Diego Bay, and fault geometries in Death Valley.

Cast housing: In another application, Rockwell Automotive's Off-Highway Engineering Div., Troy, Mich., relied on LOM to halve the development cycle for a large rear engine power take-off (REPTO) housing.

Rapid prototyping was done at 3-Dimensional Services, Rochester Hills, Mich. It took just five days to build a full-scale housing -- measuring 79 x 61 x 28 cm (31 x 24 x 11 in.) -- in the woodlike LOM paper. Foundry patterns and cores made via LOM were then sent to Tri-State Aluminum, Muskegon, Mich. Two-and-a-half weeks later, 12 prototype housings sand-cast in aluminum alloy 356.0-T6 were delivered to Rockwell. Total development time for the part was 11 months vs. the usual 18 to 24 months.