Why engineers seek solid ground

The #!$@%! part doesn't fit! No one ever utters those words calmly, especially in the latter stages of a design project. Instead, engineers often shout them through bared teeth, the words spraying like shrapnel from an exploding bomb.

Like so many of his colleagues in industry, Electroglas Inc.'s Jim Levante, engineering services manager, was hearing those words too often.

The Santa Clara, CA company designs and builds wafer-probing machines that semiconductor manufacturers rely on to sort and classify integrated circuits. Composed of thousands of parts, the machines position semiconductors under contact probes for testing while they are still in wafer form.

Under Electroglas' former 2-D drafting regimen, engineers didn't test for machine reliability, accuracy, or part interferences until after they built a physical prototype. By then, they had consumed a lot of time and expense only to discover problems with the design, such as parts that didn't fit.

That was then. Now, using 3-D solid modeling, the company's engineers conduct design reviews online. They evaluate product models early and often, and have the freedom to make changes without affecting the schedule. The result, says Levante: "We get a better product, and save money."

A lot of money, in fact. Solid modeling recently helped Levante and his engineers save $17,000 in the design of a manipulator, one of the options that comes with the company's Horizon wafer probers. The key: the ability to make sure every part fit the first time.

Within the small world of software developers, there's a lot of talk about the potential for solid modeling to revolutionize engineering. And the word has gotten out: The most recent forecast from Cambridge, MA-based research firm Daratech shows that the fastest growing software companies are those with solid modeling products--Parametric Technology Corporation (Pro/ENGINEER), IBM (CATIA and SolidWorks), SDRC (I-DEAS), and EDS Unigraphics (Unigraphics CAD and, soon, Solid Edge, which it will market with Intergraph under a separate subsidiary).

But, to find out if solid modeling really can improve the engineering process, you have to study closely the experience at Electroglas and other companies that have chucked their 2-D ways and bet the future on solids.

Windows on design. Electroglas is a great case study to follow because, under Levante's direction, the company has combined solid modeling CAD with other Windows-based engineering software for a total remake of its product-development procedures.

The importance of engineers as owners of that process has become apparent, says Brian Seitz, Microsoft's worldwide engineering industry manager, who has worked with Electroglas.

As recently as two years ago, Electroglas did everything in 2-D. Engineers and designers would create a product layout, then pass it off to the drafting department, which documented and detailed the design. "The drafter, not the engineer, was the most important person in the review process, because he gave the design team something to look at," Levante recalls.

Analysis? Engineers were doing it too late in the process, which cost time and money. Today, everything's different.

Electroglas re-engineered its engineering process around the use of SolidWorks 97, Windows-based 3-D solid modeling CAD software from Concord, MA-based SolidWorks Inc. "We now work much harder to create a capability spec, then model the product in SolidWorks," Levante says.

Seeing and believing. Designing in solids opened up all kinds of possibilities, he says. For one, it enabled engineers to visualize the product at each step of the design phase, and long before they made a physical prototype. And, by using the visualization software of SolidWorks partner Immersive Design, they can make a video version of the product so they and others can evaluate it. "That gives everyone the chance to see the design intent early, and gets engineers input from others in the company when we can use it," Levante asserts. It has also helped engineers win design approval, he says.

Using Microsoft's Source Safe, an archiving application, engineers share the solid modeling data with their colleagues. Source Safe archives all previous versions of the model, so engineers can go back to any point in the design process. Then, still within SolidWorks, they use SRAC's COSMOS/Works finite element analysis software to optimize the design by, for example, adding or removing material to make a part stronger and more cost-effective.

Virtual prototypes precede physical prototypes, which the engineers develop directly from the solid model using SURFCAM.

When the product is ready for release, they copy drawings and bills of materials from Source Safe to Agile Configurator, which the entire company uses as a product data management tool. That tool gives them the benefit of global viewing of drawings and bills of materials, and electronic handling of engineering change orders.

And, because all the software is Windows-based, engineers can release drawings to the technical publications department, which uses MS Word to create operating manuals.

The bottom line: "Solid modeling helps us identify problems early and get the design right the first time," Levante says. And, he adds, SolidWorks doesn't limit the kind of talent the company can hire. "It's so easy to learn, we no longer look for people specially trained in a specific CAD system, we look for the best people," he says.

The model-drawing connection. For Joe Slater, head of engineering and new product development at Kaiser Optical, Ann Arbor, MI, the biggest changes solid modeling has brought to the engineering process are model-to-drawing associativity, the ability to make part and assembly drawings quickly, and the ability to render images of new design concepts.

The company makes holographic optics for the military market and for industrial process analysis. Until a year ago, engineers developed the products using 3-D wireframe models. They could model anything, but rendering was limited. Engineers would make 3-D wireframes that they would send to the design and drafting department, where others would break the file into individual parts, add screw holes and other changes, and then make new drawings. "We never updated the original model, which often became obsolete," Slater recalls.

To save time and money, the designers didn't do traditional assembly drawings, which were expensive. They relied, instead, on the original models for assembly information. In other words, they depended on engineers remembering how to put the assemnbly together. Engineering productivity wasn't a problem, but Slater and his team knew they couldn't continue like that. The company was growing too fast. They wanted to move to model-to-drawing associativity. The key was to control the geometry with the solid model. Associativity features of the software would automatically update drawings and assemblies to incorporate changes in the model. To accomplish that, they chose Solid Edge CAD software from Intergraph, Huntsville, AL.

Kaiser Optical's products are almost always a collection of individual parts, and it's not possible to create new parts outside the context of an assembly, Slater says. "Wireframe models don't know anything about holes and other features, and couldn't give us the associativity between models and drawings that we needed," he adds. "Wireframes are like lines of spaghetti--you can't make any sense of them."

Slater isn't ready yet to say that solid modeling has improved product quality or engineering productivity, but he suspects it will. For now, he is pleasedwith the Solid Edge software and athow quickly the engineers learned to use it. "Our productivity was already good, and we've held ground during the switch to solid modeling, which is good enough," he says. Design, drafting, and configuration tasks have already im-proved, he adds.

Oh, and about the software's visualization capabilities: "I used to think rendered images were fluff, but that capability has really helped us communicate design concepts to management and get approval," Slater asserts. "In that sense alone, it makes my job easier."

What you see is what you get. Brian Wagner agrees. As engineering manager at Carlson Tool and Manufacturing in Cedarburg, WI, he likes the aesthetics that come with solid modeling. "You see what you'll get," he says.

Among the things he sees are thin-wall and thick-wall sections that can cause fill problems in the tooling designs his engineers develop. The company designs and builds plastic-injection die-cast permanent molds for automotive, medical, and consumer products. Customers often send the company 2-D prints, and Carlson engineers themselves worked in 2-D. But 18 months ago they began using EDS Unigraphics version 11 solid modeling software. (They had used Unigraphics for manufacturing for 13 years. Today, they use a combination of versions 12 and 13 for both design and manufacturing.)

"Now, when we model the customer's 2-D print in 3-D, we see all kinds of potential problems in areas such as radius, draft, and thick or thin walls," Wagner says. Catching those problems early saves time and money while enabling Carlson engineers to help the company's customers accomplish their own goals.

That added value was evident recently, when Carlson helped an overseas automotive customer avoid a fill problem. The customer had supplied 2-D prints for a battery cover. "We did a solid model of the part and showed them thick walls that would not fill properly," Wagner recalls. "We told them that when the plastic shrunk there would be blemishes. We re-modeled the part showing them two ways to correct the problem."

When they were working in 2-D, Wagner says, Carlson engineers would draw multiple cross sections, but they were useless for downstream tasks such as analysis or manufacturing. It was also easier to make a mistake. "Many of our parts are free-form unique shapes," he says. "We put geometry close to other geometry, and it's hard to be sure in 2-D that the parts won't interfere with each other."

The lesson from these examples is that solid modeling, among other things, reduces errors. Some say it's difficult to use. Nevertheless says Patrick Hanratty, president of MCS, Inc., "people who use 3-D solid modeling well do wonderful things with it."

Adds Microsoft's Seitz, combining solid modeling with Windows makes it easier for engineers to use the full power and functionality of CAD. "It gives engineers more time to be engineers," he says.

Check here to see if you need solids

How do you know if you should be using solid modeling? If any of these situations describe your process, you could benefit from it, says John R. Baker, product manager from EDS Unigraphics:

- Your products consist of assembled items where clearances and packaging issues are important. Unlike 2-D models, solid models show interferences and allow you to measure clearances.

- Parts in your products are machined, or you produce them using net-shape manufacturing processes, such as casting, molding, or forging. Solid modeling systems define rounded edges, drafted sides, and other detailed aspects found in those parts.

- You use images or illustrations of your products as marketing and sales aids or for manuals.

- You analyze your products for weight, or perform center-of-gravity studies. Solid modelers calculate the data for single-piece parts as well as complete assemblies, even if you make the assemblies from different materials.

- You use rapid prototyping. Solid modeling systems offer virtually the only practical way of defining parts to be produced for product validation or short production runs using today's rapid prototyping processes.

What solid models let you do- Visualize the product throughout the entire design cycle. "You can share solid models with everyone in the organization, and everyone understands them," says Electroglas' Jim Levante.

- Trouble-shoot early to identify problems like interferences early, while you can still correct them inexpensively.

- Generate part and assembly drawings quickly.

- Gain advantages of associativity, so when you change a part the whole assembly updates.

- Easily take advantage of downstream applications such as finite-element analysis and CAM.