In 1868 U. S. inventor John Wesley Hyatt, known mainly for simplifying the production of celluloid, invented an injection molding process to produce billiard balls. In 1872 he and brother Isaiah patented an injection molding machine that used a plunger, a process that remained virtually unchanged until 1946 when a man named James Hendry built the first screw injection molding machine, revolutionizing the plastics industry.

Since those early days, the plastics industry has grown to incredible portions, with virtually every product you buy—from automobile bumpers to Lego toys to lightweight, high-strength construction materials—being made from some form of plastic. The most commonly used thermoplastics include polystyrene, acrylonitrile butadiene styrene (ABS), nylon, polypropylene, polyethylene, and polyvinyl chloride (PVC).

Advances in Moldmaking Technology

But still underlying all of the advanced technology in the plastics and injection molding industries is an old-fashioned metalworking skill known as moldmaking, a skill practiced by tool and die makers and moldmakers for more than a century. In the past, molds were made using manual equipment. As a result, the process was slow and difficult and very expensive. Today, however, in certain companies, moldmaking has reached a level of speed and precision never before considered possible.

Prestige Mold, Inc.

One such company that has taken the old “art” of moldmaking to the cutting edge of manufacturing technology is Rancho Cucamonga, CA’s Prestige Mold, Inc.

“We haven’t always been on the cutting edge,” says Donna Pursell, Prestige sole stockholder and CEO. “My husband, Mike Koebel, and I started the business in our garage in 1982. He worked days at a mold shop in Upland, CA and nights in our garage. I was an accounting major in college. He made the molds, I kept the books. We made a good team, and we were successful.”

How successful were they?

“Well, today Prestige employs about 80 people,” Pursell says. “We own our own 30,000 square foot building, 90% of which is dedicated to manufacturing. We own eight Workmaster 3R robots serving four high-speed Bostomatic CNC mills, two Mikron 42,000 rpm mills, two Zeiss CMMs and eight Charmilles Roboform die sinkers. We use the high-speed mills to produce thousands of electrodes used in the die sinkers to create molds with 4 to 128 cavities. Since our garage days, we’ve grown to serve more then 80 customers, most of whom generally are large, successful OEMs. We’re proud of that.”

So why hasn’t the Prestige customer base disappeared offshore along with so many others?

“One reason they stay here is to protect their intellectual properties,” Pursell explains. “They don’t want their products being built and sold overseas before they even hit the market here. At Prestige we routinely sign nondisclosure agreements with our customers, so they feel safe with us. Plus, they just can’t get better quality molds anywhere else, we believe. We have a highly experienced staff of mold designers in our engineering department, and customers rely on us to help them design the most efficient molds for their products.”

Production Requirements

For those not in the “know”, it’s pretty hard to imagine that a moldmaker would need the huge amount of automation and technology found at Prestige Mold.

“We produce a lot of molds with a lot of cavities,” Pursell explains. “We use Charmilles die sinkers like the Roboform 550 to burn those cavities. So, if you figure that a 128-cavity mold requires at least 128 electrodes, and generally a lot more, depending on the size, depth and shape of the cavities, you start to get the idea. For us electrode production is a major part of our operation.”

To meet their production requirements and to remove the sheer monotony of manually feeding its equipment, about six years ago Prestige made the decision to invest heavily in robot automation.

“We produce so many electrodes we had to automate,” says Pursell. “We use high-speed, 30-42,000-rpm Bostomatic and Mikon milling machines to machine our graphite electrodes. We went to high-speed machining in order to quickly get the kinds of finishes we need. You can make the electrodes at slower rpms, of course, but it takes a lot longer. We don’t have that luxury.”
A bad electrode can produce a bad cavity, and a bad cavity can ruin a costly mold. So, to be sure the electrodes are “right” before they’re used, they’all 100% inspected on two automated Zeiss CMMs.

“Once again, at inspection stage, you’re dealing with a lot of handling,” Pursell says. “So, we decided to avoid bottlenecks in the inspection area by feeding the CMMs with their own Workmaster. It’s much better to catch a mistake before it happens, rather than later.”

After electrodes are checked, they’re loaded onto the company’s 8 Charmilles die sinker EDM machines to burn the molds.

Pursell: “Obviously we had to automate this stage of production, too. We try to move fast, but do it right the first time. We don’t want to burn out our employees by having them do boring, repetitive work. Our machines work 24/7 and they never complain. They free our employees to do more critical kinds of things that can’t be done by machines.”

In the past before automation, production was significantly lower, Pursell reports.

“In a 55-hour work week, we were lucky to get 45 hours of production,” she says. “Now, we’re averaging 80 to 100 hours a week and 130 hours on electrodes. The productivity increase has been tremendous.”

Grading Their Paper

Once a mold has been produced, it goes through additional stages of quality control.

“We use the CMMs and other tools to make sure the molds are exactly as they’re supposed to be,” she says. “But in the end, the real proof is the kind of product a mold produces. We operate two injection molding machines to do that. One is a Toyo Plastar Si-300III 300-ton machine. The other is a Husky 160-ton machine. These machines can cycle a 128-cavity mold every six to eighteen seconds, depending on the complexity of the product. Once our customers buy off their molds, we ship and start over again.”

Prestige also uses the injection molding machines to do short-to-medium-run part production for its customers, if they request it.

“Sometimes customers need 100,000 to 500,000 parts to tide them over until they’re ready to do their own molding,” she says. “We do it for them just to help out.”

Charmilles EDMs Only

Pursell says she can’t quite remember when Prestige Mold went exclusively over to Charmilles EDM.

“It was a long time ago,” she says. “We started out with a Hansvedt EDM in our garage, but we soon needed a CNC EDM machine, so, we switched to Charmilles. We run two Charmilles wire EDMs and eight die sinkers. Charmilles is owned by the George Fisher Group, who also owns and produces the Mikron milling machines. Their products are very high quality and very reliable. We push all our equipment very hard at Prestige and so far we’ve had little problem.”

Looking to the Future

Although Pursell is not a moldmaker, she understands the business and enjoys her role as CEO.

“When my husband passed away, we were very lucky to have Lance Spangler, who is our president and general manager ready and willing take over the technical side of the business. Lance had been with us for years and is extremely knowledgeable. Under his guidance our company has grown significantly and will continue to do so.”

In her position as CEO Pursell handles company finances and operates through a systematic management system that gives key employees a say in decisions.

“I would like to see Prestige continue our stable growth,” she says, “hopefully with the molding services contributing even more. At Prestige, however, mold making is the heart of our business. We’re moldmakers, and that will never change.”

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