Machine Design

Better wafer handling through simulation

Static or time-dependent physical responses are calculated by MSC.Nastran for Windows, including displacement evaluation.

Simulation technology let a maker of wet wafer-handling equipment go from as many as six physical prototypes to just one.

All Wet Technologies Inc., Wellsley, Mass., figures it saves as much as $30,000 per design adaptation by eliminating all but the final prototype.

MSC.Nastran for Windows gets credit for this shrinking of the development cycle. Says All Wet CEO Arthur Keigler, "Over five applications, we saved about $150,000 that would have been spent outsourcing multiple iterations of prototypes."

The software helped prove that maximum stresses were below the yield point, and thus that there was no inherent wear-out mechanism. In addition, simulation helped optimize for different applications requiring a specific range of pick-up tolerances or different acceleration and stiffness qualities.

Nonlinear analysis capabilities aided in verifying that high stress points were well within safety margins for the materials used. "My sense was that it would cost me half as much to pay somebody to do the analysis for just the first application as to buy the software. I figured it would be worth my time to learn FEA," says Keigler.

CAD models at All Wet went to MSC.Nastran via STEP files. An automesher discretized the imported models and produced results that were largely correct on the first pass, say All Wet developers.

The program has also been particularly helpful in working with elastic material properties, developers say. "We often combine relatively simple structures in novel ways where we need to know the nonlinear force deflection curve. We can evaluate a shape to determine if a concept works, then model it along with other components to more quickly get an overall design. (Without MSC.Nastran), we'd take much smaller steps between iterations and avoid the risk of trying completely new concepts," says Keigler.

TAGS: Technologies
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