A technology now under development can make an injection mold in minutes by spraying droplets of molten steel onto a pattern.
The conventional way — machining a solid piece of steel, then grinding and polishing it — has a lead time averaging three months.
With the new technology, the entire process, including design, can take only days.
``You can kind of visualize this as a souped-up paint sprayer,'' said Kevin McHugh, advisory scientist with the Idaho National Engineering and Environmental Laboratory, near Idaho Falls.
INEEL has created the Rapid Solidification Process Tooling Consortium. Active industry members in the consortium include the Big Three automakers, Baxter Healthcare of Round Lake, Ill., Procter & Gamble Co. of Cincinnati and UT Automotive of Dearborn, Mich.
``We feel very fortunate to be in on the ground floor'' of rapid solidification, said Ed Buzanoski, UT Automotive's principle engineer for rapid prototyping and rapid tooling.
Most ``rapid tooling'' methods make a mold that can run a limited number of parts. The big push now is to make production tooling.
``We have not done a production mold [by RSP] yet at UT,'' Buzanoski said. ``But we are planning to do that later this year.''
He declined to say what part the mold will make, but said it will be used for a glass-filled resin.
INEEL's McHugh explained how the method works: Molten tool steel or another tooling alloy is pressure-fed into a nozzle, where it comes into contact with a high-velocity, high-temperature, inert gas.
The gas atomizes the metal into fine droplets and sprays them onto a tool pattern made from wax, clay, plastic, ceramic or metal.
The droplets solidify quickly, in a process that actually starts as they fly through the air toward the pattern.
After the metal block cools to room temperature, it is separated from the pattern.
A drawback is the steel cannot be sprayed into deep, narrow spaces because it builds up at the mouth of the space, blocking the inside.
On the other hand, McHugh said, ``the level of detail is pretty incredible.''
Researchers have sprayed the metal into a glass plate with a fingerprint impression on it, replicating the fingerprint in steel.
One consortium member is captive injection molder Hach Plastic Products, a division of water analysis equipment maker Hach Co. in Loveland, Colo.
Bob Hewson, senior tool designer, said Hach Plastic, which builds its own molds, has explored several other rapid tooling technologies. He thinks the spray-on-metal method of mold making could decrease the company's tooling costs significantly and slash the time it takes to make new molds.
``This has very good potential,'' Hewson said.