ORLANDO, FLA. — Think you make small parts? An industry panel at Antec 2000 described the brave new world of micromolding, where a day's worth of resin fits into a small envelope, molds get shipped via Federal Express and touching the parts — if you can even see them — is taboo. Everything about these parts is tiny. Measurements are in millimeters and microns.
"We usually carry our molds around in our hand," said Stuart Kaplan, president of Makuta Technics Inc., a micro-injection molder in Columbus, Ind.
Kaplan recalled how a new intern accidentally sneezed and scattered a day's worth of production across the room.
Members of the five-member panel, held May 10 during the conference in Orlando, said micromolding can be challenging, sometimes frustrating work. The market is growing, especially in medical products and electronics such as cellular phones.
Ethicon Endo Surgery of Cincinnati has been studying plastics for the tiny gears and other components it uses on devices it makes for doing endoscopic surgery — operations that use a thin tube fitted with a camera and surgical equipment to probe inside the body.
"Everything that goes through that tube has to measure 3 millimeters or less," said Robert Alvarez, a plastics engineer at Ethicon. "They're very, very tiny devices stressed to the absolute minimum."
Endoscopic surgery is growing because it is considered less invasive, and less expensive, than traditional surgery. A patient can recover much quicker, he said.
In the future, mechanical implants also will require miniature parts, whether plastics, ceramic or metal. Medical experts are developing tiny pumps that would remain in the body to deliver medicines.
"It's probably smaller than you can actually see, and it's an actual, working pump," Alvarez said.
How do you inspect a 10-micron part? X-ray diffusion is the only way, Alvarez said. "You can't do it optically."
How do you assemble parts you can't even see? Alvarez said all the assembly equipment has to be custom made. "Probably there aren't more than three or four companies in the whole world that are capable of making this type of equipment," he said.
Makuta is allied with Japan's Sansyu Group of companies, which claims to be the world's largest micromolder. Before joining Sansyu, Kaplan worked at his family's metal fabricating business, which stamped big parts for fuel tanks, along other things.
Talk about culture shock. Kaplan found himself in Japan molding parts like a 1mm coil bobbin for a tiny motor.
"It was a total change in attitude for me," said Kaplan. He learned to inspect parts using an electron microscope and a pair of tweezers. "There's no way you can touch them. They have to be checked by vision systems."
In Indiana, Makuta runs 17 Sumitomo injection presses. "Our maximum tonnage on our machines is 18 tons, and we go down from there," he said. The plant runs 24 hours a day, seven days a week with just 20 employees.
Murray Inc. of Buffalo Grove, Ill., makes a special machine called the Sesame NanoMolding press, which is used for micromolding. Murray President Phillip Leopold explained the name: "You can get about 20 of these sesame-seed-sized parts out of one pellet of resin."
The press, using electric and pneumatic power, uses two plungers, one that charges the shot and the second that injects plastic into the mold.
Leopold said the Sesame process mimimizes the sprue and runner — an important feature in micromolding, where those waste parts are bigger than the actual, minuscule part. In fact, George Shevchuk, of Bell Laboratories, joked that technicians there call micromolding "controlled flash."
Shevchuk described two fiber-optic parts and one connector developed by Bell Labs in Murray Hill, N.J.
One way to avoid a sprue is to inject at the parting line of the mold. SPM, the custom injection unit of Dynacast International Inc., adapted a four-slide process from the die-casting industry, according to Richard Brock, business development manager at SPM in Anaheim, Calif.
The four slides run in channels cut into metal, so they hold the tiny mold face very tightly.
Brock said SPM does micromolding on fairly simple, pneumatic plunger machines.
In a question-and-answer session, Alvarez said he still has many questions about micromolding, even after studying it for Ethicon for several years.
"If you think you're going to just walk into this business and buy your equipment and make parts, you're kidding yourself," Alvarez said.