Computer software will 'automate' concurrent engineering of plastic parts.

The Design & Manufacturing Institute at Stevens Institute of Technology in Hoboken, N.J., is developing "automated" concurrent-engineering software for design and manufacturing of injection molded, long-fiber reinforced thermoplastics.

The goal of the program is to create an intelligent, "feature-based design" software system that can automatically integrate various constraints on an injection molded component (for example, part design, tooling costs, and polymer flow properties) into the initial design concept stage.

Such a software tool, if successful, could assist processors looking to join the ranks of "world-class" manufacturers and participate in "strategic partnerships" with end-user customers. Strong internal part/tooling design capabilities are recognized as an essential trait in the world-class processor profile (see Jan. '92, p. 48 and April '91, p. 84).

'AUTOMATED' DESIGN

The main thrust behind all concurrent-engineering concepts is to achieve maximum flexibility, cost-effectiveness and time savings by having manufacturing guidelines and constraints built into the design process at the initial concept phase. Normally this involves the direct human interaction of numerous experts in design, materials, tooling, and manufacturing. The Institute seeks to "automate" this process through the use of computers. By integrating a variety of databases and specialized software, the Institute aims to make manufacturing intelligence readily available, on an interactive level, at the initial stages of the design process.

The Institute's software development project is being funded by a three-year, $15.5 million U.S. Navy contract, which began in September 1991 and is due to be completed in September 1994. Additional funding comes from AT&T, Digital Equipment Corp., State of New Jersey (with matching grants from Stevens Institute), and the U.S. Army Research Office.

At the end of the Navy contract, the Institute is expected to deliver a fully functioning software system to be used in the design and production of two injection molded prototypes: an environmental control valve for an F-18 aircraft; and an electrical housing for an unnamed Army vehicle. After demonstrating its success in these military applications, the software will be made commercially available to domestic processors to help them leapfrog offshore competitors.

COMPUTER-AIDED ENGINEERING 

According to Institute directors Stephen J. Tricamo and Donald H. Sebastian, an automated concurrent-engineering software system would have the capacity to drastically condense (by up to 70%) the time and effort required to design and produce injection molded parts, compared with conventional engineering approaches. The two directors see the concept and initial design phases--the "front end" of the traditional engineering process--becoming the dominant steps in part development and production. The bulk of the time and cost savings would be culled from the design-revision and data-dissemination steps, which traditionally represent the greatest portion of time and cost for developing new parts and tools.

The concurrent-engineering software would transform part-design specifications into a complete, computer-aided sequence of mechanical design, material selection, mold-filling analysis, and selection of molding process conditions, as well as NC machining instructions for cutting the mold.

Tricamo and Sebastian say injection molding of engineering thermoplastics is a manufacturing process that readily lends itself to this unified, computer-aided, concurrent-engineering concept. They explain the software will capture the many variables of the injection molding process, mold design and gating considerations, polymer properties, cost of tooling, and cycle-time projections, allowing those data to steer initial design concepts.

"Our goal is to have real machinery and polymer capabilities and various processing constraints embedded into the program, so that they can be used concurrently in the design stage," Sebastian says. "We're developing a vertically integrated software system that will attempt to coordinate the entire design and manufacturing process. Our attempt is to allow the creative design process to take place while concurrently applying downstream tooling, processing and cost constraints."

Sebastian says the concurrent engineering software available today basically is analysis simulation; it doesn't provide information on how to fix or recognize manufacturing problems, or how to design a mold for a part. The Institute's "automated concurrent engineering" software for CAD/CAM systems would provide a "live" computer screen readout of tooling and manufacturing data, automatically updated with every design change. Sebastian cites the example of simply adding a boss as a new feature of a plastic part design: the new software would automatically update all parameters of mold design, gating options, optimum polymer choices for desired mold-filling characteristics, part stresses, processing conditions and cycle-time economics.

LEADING-EDGE TECHNOLOGIES

Tricamo says the program will focus on part design for long-fiber reinforced engineering thermoplastics such as nylon, polycarbonate, PEEK, and ABS. Fiber selections would include glass, carbon and steel (for conductivity). The software will take into account more than just traditional injection molding capabilities; the Institute is giving special attention to the new "multiple live-feed" Scorim process, available in this country from Scortec Inc., Gulph Mills, Pa. (PT, Oct. '92, p. 17). This process presents special opportunities for enhancing properties of fiber-reinforced parts. Rapid prototyping via stereolithography is another cutting-edge technology being incorporated into the software system.