Pressure intensifies to link mechanical with PCB design

Electronic News, Nov 18, 1991 by Jeff Dorsch

CHICAGO -- Time-to-market pressures are leading manufacturers to telescope the once-separate processes of electronic and mechanical design, forcing software vendors to provide bridges between the two-dimensional world of printed circuit board design and the three-dimensional world of mechanical design.

The shrinking of enclosures for boards in aerospace, automotive and consumer electronics is causing cross-pollination between electronic and mechanical design methodologies, and designers seek alternatives to using standard "rack" board sizes.

The customary method of designing a board in a standard "rack" size and throwing that design "over the wall" to a product's mechanical design team is being increasingly challenged all over the industry, according to vendors exhibiting at last week's Autofact conference. Using concurrent-engineering techniques, many manufacturers are specifying non-standard forms for their boards early in the design process and are having their electronic and mechanical engineers work simultaneously.

Typical of the new world order in electromechanical design was the disclosure last week of a joint development and marketing agreement between Schlumberger CAD/CAM and Valid Logic Systems. The companies will link Schlumberger's Bravo3 mechanical design tools with Valid's software for circuit design, simulation and board layout.

"Using these interfaces, customers will be able to determine the size and shape of a PCB in Bravo3, transfer that geometry to Allegro (Valid's board design software), lay out the components on the board, then take it back into Bravo3 and place it into a mechanical enclosure. From there they can package the system, check for interferences and perform thermal and structural analysis," said Brad Morley, president of Schlumberger CAD/CAM.

The Autofact technical conference devoted a session to integrating electronic design automation and mechanical design automation, with presentations from Structural Dynamics Research Corp., Mentor Graphics Corp. and Norand Inc.

Customers lashed on by the increasing pressure of global competition are driving the closer ties between vendors of electronic and mechanical design software, executives said. SDRC was led to establish formal relationships with such EDA vendors as Mentor, Valid and Racal-Redac by customers saying "We really want this interface," said Edwina L. Wedeking, industry marketing manager for SDRC, a supplier of mechanical design tools.

Product design in the past "was very much driven by electronic engineering," Ms. Wedeking noted, but such important considerations as board size and shape now are "a lot more frequently driven by the mechanical side."

Having mechanical tools which can "read" data from EDA packages was fairly common; now it is becoming more critical to make those interfaces bidirectional, because "customers want to read data back," Ms. Wedeking commented.

Years ago, turnkey CAD/CAM vendors could provide an integrated electromechanical design and drafting suite, but the offerings typically were "extremely restrictive," the SDRC executive noted. "A good wireframe design package would not bundled with a so-so PCB package."

Then the EDA startups, Mentor, Valid and Daisy Systems, "made it hard for the turnkey vendors to keep up with CAE and CAD/CAM for electronics," Ms. Wedeking said. Although mechanical CAE companies like SDRC also emerged in the 1980s, manufacturers found themselves with "a bottleneck in mechanical design" because there was no way "to make these two separate design systems talk to each other."

Solids-based interfaces are making it possible for the gap between EDA and MDA to be bridged efficiently. SDRC is pursuing relationships with Zuken, the leading Japanese supplier of PCB design tools, and the P-CAD unit of Cadam, which sells through a number of VARs, to broaden its links in the EDA world, according to Ms. Wedeking.

Enhancements that need to be made include "reducing the number of steps to generate the physical model," she said. System-level engineers are interested in thermal analysis, another facet which can be improved upon.

Mentor's dropping of its mechanical design line (EN, Aug. 26) means there is "no longer any concern on their side on how to position their products alongside ours" through Mentor's Open Door program for marketing third-party software, Ms. Wedeking observed. "In general, we didn't have a lot of competition (between Mentor and SDRC packages), but it helps to improve the relationship."

Massood Zarrabian, vice president of CADDS marketing for Computervision, sees the integration trend being driven by a desire for vendor simplicity. "Customers prefer one or two vendors, not 275," he said.

Designers of automotive electronics are among those with the need to combine electronic and mechanical design in an efficient way. Thermal analysis of automotive PCBs is especially important, since car manufacturers don't have the luxury of sticking a fan next to every electronics assembly, Mr. Zarrabian noted. "They will not change the car body for many things."