NOVI, MICH. — Computer-aided engineering is sparking a running feud between old-school and new-school parts designers.
The old-school view goes something like this: A part is designed, borrowing from dozens of hard prototypes, and then passed to engineers for physical testing before it is ready for production.
``It's a fairly intuitive process and based more on judgment calls than computer analysis,'' said Anne Bernhardt, president of Dallas-based Plastics & Computer Inc., a software consulting firm. ``You feel like you can't mess up too badly with all the years of experience you have.''
The new-school view, practiced by automotive molder Key Plastics Inc. and others, turns that theory on its head. The supplier has resolved to pare pre-production time to a minimum by using CAE tools concurrent with computer-aided design.
A goal is to let the speedier, virtual world of computer simulations absorb some of the labor-intensive work of testing and building prototype models.
It is a departure from the show-me approach of older design engineers, said Kenneth Haviland, CAD/CAE engineering manager for Novi-based Key Plastics.
``Some people misperceive CAE tools to be only a trend and not factual enough to take at face value,'' Haviland said. ``But we don't want to re-create the wheel every time we make a product. [CAE] helps us streamline the design process and contain costs.''
Key Plastics has a 45-person technical center in Novi that includes five CAE engineers. Four years ago, when Haviland began managing the center, it had fewer than 10 people, he said.
Unlike most processors with design studios, at Key, a design engineer only performs rudimentary CAD work before passing the design to a CAE expert.
The part then is put through an extensive battery of computer-driven tests. They include some of the fundamentals of CAE, such as mold-filling simulations and finite-element analyses to predict impact resistance.
But the tests also include computational fluid dynamics to depict air and liquid flow in such parts as air vents; light analysis to show how natural light affects a dashboard graphic; noise, vibration and harshness tests; kinematics to depict how vehicle motion dislodges a part; and cubing-room software to predict surface quality.
``We can do a lot of the engineering work by computer,'' said Payman Afshari, senior CAE technical specialist at Key. ``We don't need to do a lot of physical testing.''
Only then is the part looped back to the designer for finishing details before it is cut loose for production tooling and final validation.
The idea is to spend more time testing a part by computer to avoid designing a part that might never get past the studio door, said Calvin Saur, Key Plastics' vice president of global technology and product development.
``You never have good design unless you have a robust process,'' Saur said. ``We design all our parts for manufacturing and assembly. CAE tools are the driving force for that.''
Ideally, those CAE tools will eliminate the need to make early prototypes in design, said Mike Heskitt, director of the engineering services division of Troy, Mich.-based firm Altair Engineering Inc.
``In plastics, many suppliers are just coming off the curve gaining expertise to apply [CAE],'' Heskitt said. ``The goal is to have the first test work be successful with CAE and only use prototypes for final testing.''
In the auto industry, CAE work traditionally has been done by carmakers, Heskitt said. Now, those companies are beginning to push suppliers to perform those services and invest in CAE tools. That has led to an abundance of work for Altair to get suppliers up to speed, he said.
Haviland said Key greatly has reduced the number of prototypes it needs to produce. The company uses a fused-deposition modeling rapid prototyping machine to assist with quick part development.
Production and assembly run on the same math-based data.
Using both rapid prototyping and CAE make time and cost savings even more dramatic, Haviland said. A typical door handle can be made in 12-14 weeks instead of six months or longer, he said.
Yet, some companies working outside the automotive industry are not quite ready to give up their prototypes just yet. Doing that could be a bit rash, said marketing manager Mark Powers of Sundberg-Ferar Product Development Inc., an industrial-design firm in Walled Lake, Mich.
The firm performs a great deal of consumer product design work for Whirlpool Corp. and other companies. And prototypes are still a necessity, according to Powers.
``You can't get away from the need to make something physical,'' he said. ``We preach pretty religiously that seeing a green widget on a [computer] tube is nice, but you need a physical iteration of it. You can't feel it and see how it goes together unless you create prototypes.''
The same goes for Mack Group Inc., a large processor of consumer and electronic plastic parts. The company, headquartered in Arlington, Vt., uses CAE tools to analyze mold flow and uses prototype parts to help it learn how a part will function, said Mack senior staff engineer Randy Pell.
The problem is that CAE tools are only as good as the best operator, said Pell, whose company has set up a separate design group to manage projects for customers.
``You need someone who knows that a part just doesn't look right after a computer analysis,'' Pell said. ``But a cheap prototype tool, made from aluminum or new epoxies, might help you do that, too.''
Still, cost savings with CAE tools can make a difference, said Sandy Munro, president of Troy-based manufacturing consultant firm Munro & Associates Inc. Crash tests alone on vehicles can cost $500,000, at the very least. Computer simulation software, which can cost around $20,000, could perform some of that work, he said.
Some suppliers still are loath to use it regularly, Munro added.
``But it takes a paradigm shift,'' Munro said. ``It's a matter of getting people to accept data and utilize tools in front of them. There's still a fear of the unknown because it's a computer and not real to some people.''
The firm has a design and training technology company called Command Train Inc., which helps designers and engineers use CAE tools. Command Train Vice President Lawrence Maples said designers and engineers have begun to work together.
In one instance, for a windshield-wiper module, product-development time dropped from 18 months to six months, he said.
``We've heard about making a design and then throwing it over an imaginary wall to an engineer,'' Maples said. ``Well, now, we're starting to see some holes in that wall. It will continue to happen.''