This technical information has been contributed by
Proto Labs, Inc.

Injection Molder Streamlines Operations with Proprietary CAD/CAM Software

Plastic Injection Molding

Standardized production methods bring fast turnarounds and low-cost tooling into play.

The Protomold Company is playing a big part in the frantic drive to market for products needing plastic parts. The medium-sized Minnesota job shop is focused on a manufacturing niche that has it turning out prototypes and low-volume plastic parts of moderate complexity. A high-tech contract manufacturer, Protomold has standardized its niche to such a degree that it can offer extremely fast turnarounds at very reasonable rates.

"Real parts, real fast, with real savings" is Protomold's motto, one that the company has reportedly lived up to since opening its doors in 1999 in Maple Plain, Minnesota, near Minneapolis. The company, which recently doubled its facility space to 30,000 square feet, operates 10 three-axis CNC milling machines for tooling; it also operates 12 injection molding presses, ranging from 50-ton to 300-ton capacity. The firm employs 70 on three shifts, and has a full-time quality engineer.

"We are a very fast, inexpensive way to get injection molded parts from 3-D CAD models into the hands of a designer," says the company's president, Brad Cleveland. "We can only do a certain size and complexity of plastic part, but I think that our company can consistently get OEMs these standardized parts faster and cheaper than anyone else can," Cleveland added. "We can do this because we make our own tooling in-house and perform the injection molding, we stock almost any plastic material imaginable, and we've developed our own CAD/CAM software for the quotation and production processes. So we've removed all of the manual tasks of designing and manufacturing the molds."

Cleveland says that Protomold typically turns work around in one third of the time and with one third of the costrequired by most other injection molders doing the same type of work. He insists that many molders would take six to eight weeks to finish a part that Protomold can mold in two to three weeks. For a premium price, the company can ship a part in five days. Protomold's proprietary CAD/CAM software has automated the design process to the extent that the average cost of its soft aluminum molds for the average part is about $3,300. The tooling, which might cost over $10,000 at another vendor, is most cost-effective in the hundreds or thousands of parts, up to 10,000 parts per year.

Meteoric Growth

The niche-oriented company has grown its operation impressively in all respects: revenue, production output, workspace, and number of employees. From 1999 to 2000, the company tripled its number of employees; it tripled the number again from 2000 to 2001, and once more from 2001 to 2002. So far this year, the fledgling injection molding company has doubled the size of its operation. Not surprisingly, Protomold recently received the Rising Star Award in Deloitte & Touche's Technology Fast 50 Program for Minnesota. The program honors the 50 fastest growing technology companies that have been in business in the state for only three years.

"I attribute this incredible growth," says Cleveland, "to a great business idea by our founder, Larry Lukis. And also to the fundamental, value-added benefit we offer of dramatically reducing the time and cost of getting real injection molded parts into the hands of designers."

Since its customer base is very diverse, Protomold has no "primary" markets. However, the company manufactures many enclosures and handles for consumer appliances, as well as a large amount of electronic enclosures, automotive mechanisms, and medical device parts.

Protomold's entire management team is staffed with engineers, several of whom are also software developers, which is unusual for a job shop. The firm's proprietary software completely automates the quoting and designing process and creates commands for its CNC milling machines to make the mold. Customers first provide a 3-D solid model over their website with all of the geometry they want on the part. Then, typically within a few hours, the customer receives an e-mail with a hyperlink to a webpage on their server for their ProtoQuoteTM software.

"ProtoQuoteTM is very high-tech," says Cleveland. "It has screen shot illustrations of the part and it's interactive with pull-down menus. Our customers can adjust things like delivery times, materials, number of mold cavities, and surface finishes. And the price automatically updates each time they make a selection."

Protomold's software can also provide customers with design guidance, because the company says that most CAD/CAM software doesn't offer a high level of this type of support. A customer might want to check out an illustration on a corner of their part that is too thick for injection molding, or that needs to be thickened, or they might want to look at a wall that may distort when it's molded.

"Right now we're limited to straight pull molds," Cleveland says. "Any part that has an undercut in it and requires a side action, we can't support it. If someone needs an undercut, like a through hole, our software will identify that and recommend that they need to remove that feature or adjust their design so we can manufacture the parts cost-effectively. We will, however, be supporting molds with simple side actions early in 2004."

If the customer is pleased with the quote and decides to order, they can do so online. Their design runs through Protomold's manufacturing software, which automatically creates a mold design. The high-tech software handles the splitting of the core and cavity, generates designs for shutoff surfaces, and adds gate locations and ejector pin placements. It then automatically generates tool paths for milling machines to machine components for the mold.

Any molder could piece together a variety of different off-the-shelf software to do all of these functions, according to Cleveland. But Protomold's program is one complete, seamless piece of software that does everything in unison.

"I've yet to see anyone come up with the cost and time efficiencies that our software has brought to this market," Cleveland continues. "We can control all of these processes much more efficiently with our complete package. We're now in the process of designing a program that will automatically control our milling machines to do side actions. In this way, we will be able to do bigger and more complicated parts very quickly."

Cleveland acknowledges that there is a place for rapid prototyped parts made by stereolithography, fused deposition modeling, or 3D printing. He believes, however, that injection molded prototypes have a number of advantages for functional testing, for volumes in the range of 50 to 100 parts, and for clients who want to see their new part in the actual material in which it will eventually be molded. Nowadays, a great many thermoplastic materials can be injection molded: Protomold stocks 300 different resins, even a glass-filled polymer, to decrease production times. And because the firm's molds are made so efficiently, mold tooling can be remade inexpensively if changes or modifications are made after the first prototype.

At this time, the firm's largest press is a 300-ton unit that limits projected area to 75 square inches. The biggest mold that Protomold can build is approximately 3 inches deep x 10 inches x 20 inches; maximum achievable depth is nominally +/- 1.5 inches from the parting line. Tiny parts, only inch in size, can also be molded effectively. Tolerances vary depending on the amount of shrinkage of the material being molded. A typical tolerance for Bayer Lustran ABS, for example, would be +/- 0.003 inch, and +.002 inch/inch.

Protomold strives to offer not only parts, but also solutions to customers' technical challenges. One instance was for an OEM that manufactures personal digital assistants (PDAs). The part was an enclosure for the manufacturer's first hand-held electrical device. According to Cleveland, the device was designed to assist golfers by giving them information about how to play a particular course. The startup company needed prototypes, but wasn't sure how to procure them cost-effectively.

The OEM first decided to have the enclosures made by RTV molding, at a cost of about $50 per part. But because the enclosure came in two halves, and the company would eventually need 100 parts of each half, the method would have been expensive. The company then obtained quotes for standard injection molding. The first molder wanted $40,000 and twelve weeks to do the 200 parts. At this point, the OEM's owner was getting frustrated, and because his investor was threatening to pull out of the project, he needed to find a cost-effective alternative.

The part's designer suggested that Protomold be given a chance to bid on the part. "We were able to make both molds and ship the 200 parts for about $8,000, and turn the job around in 15 days," said Cleveland. "He was able to keep his investor, he saved some startup money, and he was able to start selling the product very quickly. We're now doing his production work at hundreds of parts per month. We're able to do this for our customers all the time."

This technical information has been contributed by
Proto Labs, Inc.

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