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September 4, 1998

4 Min Read
Fast tools (and prototypes) reach new heights


Rapid tooling patterns and masters in ABS just took a giant step up in size with the introduction of a new FDM system called Quantum, Automotive, aerospace, and information technology markets are driving the trend toward larger build areas for low-volume rapid tools. According to Stratasys' Jon Cobb, compaines such as Sun Microsystems, Motorola, Westinghouse, and Whirlpool are at the leading edge of this demand.

When Stratasys (Eden Prairie, MN) embarked on the concept phase of its next-generation FDM system, developers began with a survey asking users what they wanted. Five hundred respondents came up with the following top five key items: equipment reliability, low price, materials for a wide variety of uses, ease of use, and model quality. Those involved in moldmaking for automotive, aerospace, and consumer electronics added another requirement - larger build envelopes. To that end, the company recently introduced the FDM Quantum, with a modeling size of 11,000 cu inches, or 23.6 by 19.7 by 23.6 inches. That's 30 percent larger than the company's former size champ, the FDM 8000.

Before we go any further, however, let's take a moment to answer a question many readers have undoubtedly asked themselves. What is the bottom-line benefit of rapid prototyping for tooling? IMM checked with automotive OEM Fiat to find out why it invested in an RP system.

Fiat wanted to find a way to lower costs of molded parts for limited-edition vehicles, those that reach about 400 annually in production volume. One such part, a front-door window guide, was selected as a benchmark project to determine the benefits of rapid prototyping. Designers sent the CAD file to an FDM 1650 and built an ABS pattern master prototype. The pattern master was then sprayed with metal to create the low-volume core and cavity set. And the results: the sprayed-metal tool vs. traditional tooling took six and a half weeks from concept to tool rather than 30 weeks, at a tool cost of $18,000 vs. $30,000. Success gave Fiat the green light for future rapid prototyping projects.

A corollary to this type of benefit involves molders and OEMs, who often send out part models for tooling quotations. That was the case at Cutler-Hammer, an Eaton Corp. division that makes industrial controls. Using a rapid prototype modeled in ABS material, designers were able to send the actual RP part out to moldmakers for quotations. Because the part left no ambiguities, toolmakers were able to deliver lower quotes, with reductions estimated at 8 to 12 percent.


A touch-screen interface called TouchWorks offers users a quick display of machine status as well as a self-diagnostic program. A magnetically controlled extrusion head inside the unit rides on an air bearing for greater velocity and accuracy.

We asked Jonathan Cobb, vice president of marketing for Stratasys, why leading RP vendors are introducing larger, more complex machines such as the FDM Quantum. "Customers are becoming more sophisticated in their usage of RP and in their needs," he says. "Many are looking at rapid prototypes for tooling applications, and that generally means larger build areas and greater feature detail, surface finish, and integrity to the CAD file." To improve these latter three features, the Quantum includes an electromagnetic motion control unit to drive the x-y motion of the extrusion head more accurately. The head rides on a cushion of air, allowing greater velocity with less friction. Accuracies range from +/-.005 to +/-.0015 mm at speeds up to five times faster than the FDM 8000.

Xerox Corp., a long-time Stratasys customer, performed some beta testing for the Quantum. "Xerox was interested mainly in ease of use," recalls Cobb. Five employees from the tool shop were trained to operate the system, which uses a touch-screen control that can be networked into a manufacturer's Windows NT or Unix computer system via ethernet or 10 Base T. According to Cobb, the training process was completed in a few days.

Stratasys begins shipping the Quantum this month. Prices range from $325,000 to $435,000, comparing favorably to SLA and SLS systems in the more than $400,000 range.

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