Working Model 4D from MSC.Software, Los Angeles, produced the photorealistic and accurate mechanical prototype for a lift mechanism. Suspa's Lasch says the software made easy work of sizing three internal springs.

An integrated system of solid modeling, motion, and stress analysis lets designers be more certain their mechanisms will work as intended before building expensive physical prototypes.

"The software is helping us reach a goal of only one prototype per design," says Jeff Lasch, an engineer with Suspa Inc., Grand Rapids, Mich., a manufacturer of gas springs, dampers, locking gas cylinders, and hydraulic-lift systems. The software keeps the design team from shuttling between the engineering department and the tool shop with iterations. Lasch says implementing the motion-FEA software has reduced the time he spends on a design because he no longer has to wait to see if the physical prototypes work.

After modeling a particular design in SolidWorks, Lasch seamlessly brings an assembly into the mechanism modeler to simulate its motion, and calculate and display dynamic forces for finite-element stress analyses. "The software lets us consider the dynamic nature of a problem and simulate the entire assembly, rather than only a part or a small subassembly as hand calculations would allow," says Lasch. Dynamic analysis leads to more accurate FEA results than would be possible by guessing at loads. In addition, the system's simplicity makes it practical to apply several times in the design loop.

Photorealistic imaging in the software also helped secure funding for a project that would have been difficult to describe in 2D prints alone. The model of one production machine, for example, involves several slides, grippers, and a welder, all moving in a precisely choreographed sequence. "Showing managers a working digital design and the accurate mechanical modeling to back it up earned us the go-ahead for the project," says Lasch.

--