Ward’s Auto World
March 1994

That Buzz You’re Hearing is…
Robust Engineering

It’s gaining steam to slash time and costs
in product development

By: David C. Smith and Jon Lowell

Difficult to define and vaguely understood outside the technical community, a concept called "robust engineering" rapidly is becoming the auto industry’s hottest new methodology to produce dramatic jumps in quality and reliability at affordable costs.

Although elements of the idea date to the 1960s and have been practiced be Japan’s automakers for decades, robust is just now winning converts in the United States.

Some describe it as just plain good engineering and not all that joltingly new. Others view it as merely another fad, a buzzword for the honeybees to flock to. Asked if he can describe robust engineering, Robert C. Downs, chief engineer-transmissions at General Motors Corp.’s Saturn subsidiary, simply replies, "No, but I believe in it."

Using robust methods saved time and money in developing Saturn’s manual and automatic transmissions, he says, and also produced about 30 new patents. Warranty costs, he says, have been almost non-existent. And thanks to robust principles, the "intelligent computers" controlling Saturn’s automatic transmissions automatically switch to a "limp-home" mode if they detect a system failure, says Mr. Downs. That, he underscores, is an important warranty consideration.

Most who take robust thinking seriously basically agree with Tony Derhake’s description quoted on our cover. Mr. Derhake, chief engineer at GM’s Buick Motor Div., says robust is tough to assimilate because it calls for a paradigm shift in engineers’ long-standing way of doing things.

Historically, he says, engineers have been reluctant to release component and system designs, tweaking them over and over, creating havoc, delays and costs in manufacturing and assembly operations, and raising the potential for client complaints in real-world driving. "This was very slow and costly," he says.

Robust forces engineers to consider all facets of a design up front, including whether or not components and systems can be easily and simply produced at target costs, he says. "If you look at the design from a robust viewpoint going in, then you don’t have to make all of those changes," he says. Importantly, engineers must look at how each component or system reacts with its neighbors both from a product-design and manufacturing viewpoint, he adds.

Still, perhaps the single biggest driving factor in the growing implementation of robust engineering principles is rising client demands for quality and reliability, which have triggered stronger manufacturer warranties and a concurrent explosion in warranty costs.

Experts say only a new approach to engineering predictability into components and systems can make a long-term dent in these costs as cars and trucks become increasingly complex.

Sources say Ford Motor Co. alone spent a staggering $3.2 billion on warranty claims in 1992. A Ford spokesman will neither confirm nor deny the accuracy of the highly secret number. GM and Chrysler Corp, officials also stonewall on the subject, but their costs are believed to be vaguely proportional to Ford’s based on their size. That could put GM costs for 1992 at some $5 billion and Chrysler’s at more than $1 billion. A rash of recent recalls, however, won’t help hold down Chrysler’s warranty costs this year.

Ford, judged by most to be the leader among the U.S. Big Three in spreading the robust gospel, apparently is confident enough about the results it’s getting that it will offer a dramatically reduced 100,000 mile (160,000-km) engine and drivetrain maintenance schedule on its new Mercury Mystique and Ford Contour compacts scheduled for Introduction in September. Ford’s longer0term goal is to build cars

and trucks with 150,000 (240,000-km) durability.

John J. (Jay) Wetzel II, Saturn’s top engineer from its start in 1985 and since late year vice president for GM’s North American Operations (NAO) Engineering Center, puts it this way: " Robust is common-sense, darn good engineering. No paragraph can really describe it; it’s a total process. It involves

a lot of interaction."

Mr. Wetzel says the major driving forces behind robust engineering are-and each is equal-designing to satisfy clients in all driving conditions; manufacturing processes and capabilities; cost; quality; and reliability. "We’re pushing for engineering solutions that optimize each one of those," he says.

He and others, who embrace robust engineering principles, are convinced they eliminate wasted effort, time and cash throughout the engineering and manufacturing processes. And, Mr. Wetzel emphasizes, the entire process is to be approached on a team basis, with engineers and manufacturing folks rubbing shoulders closely –something that has not been common practice until very recently in the U.S. auto industry.

Distilled to it’s basics, robust engineering involves setting engineering goals to develop component designs that are immune to uncontrollable factors (called "noise" by robust’s practitioners), such as changes in the manufacturing environment, the kind of weather in which cars and trucks operate or how owners drive their individual vehicles.

Among the U.S. pioneers in teaching robust engineering principles is Dr. Genichi Taguchi, executive director of the Allen Park, MI-based American Supplier Institute (ASI). Dr. Taguchi is widely acknowledged as a leader in the U.S. industrial quality movement and he’s given credit for starting the robust design movement in Japan more than 30 years ago.

ASI conducts seminars across the U.S. on robust engineering and quality-related subjects, but auto industry enthusiasm for the concept has spread well beyond the seminar circuit.

The level of interest is high enough at the Big Three that there is talk of taking the concept beyond existing Japanese efforts. Some U.S. engineers think the Japanese ways that produce "over-engineered" components.

But beating the Japanese at what is essentially their own game may prove to be a slippery slope climb. The Japanese in the past have been more comfortable with innovative new engineering approaches than their American counterparts, and they aren’t likely to give up leadership in these concepts without a fight.

The next step is what is called "robust technology development," which emphasizes technology readiness, flexibility and reproducibility. Some engineers in Japan have been using it for several years, as have their colleagues in Taiwan.

"So far, Japanese companies appear to be ahead in the number of applications, which will help bolster their technological capabilities," writes researcher Yuin Wu, in an ASI paper. "This should represent a strong concern, if not forewarning, to U.S. Firms."

Nowhere is there that interest more keen than at Ford, where a new organization –the Ford Design Institute (FDI)-was established in November 1991 to formalize teaching and to implement robust engineering based on the Taguchi principles.

FDI was formed after a multi-functional Ford team benchmarked educational and training processes at corporations considered to be leaders in their industries in terms of product development processes.

FDI’s first and current dean is Minoo P. Billimoria, who joined the company in 1963 and previously served in management positions with its Alpha super-secret advance engineering/manufacturing team.

Mr. Billimoria’s full-time staff numbers only six, but he draws on experts within Ford as well as outside consultants. He has a 14-person board of directors that includes eight Ford executives and six outsiders, three from other corporations and three from the academic community.

But it’s not all theory that’s being taught: FDI undertook 40 "case studies" seeking actual solutions using the robust approach in 1993 and 40 more are scheduled this year. They range from eliminating brake squeal to improving fuel-delivery systems, both common causes of client complaints.

"My job is to change the fundamental way of doing business in engineering community," says Mr. Billimoria. FDI’s long-term goal is to spread the robust message to Ford’s 14,000 U.S. engineers.

"Robust is not easy to understand, so we began doing case studies last year," he says. In one instance, an FDI team found a solution in three months that he calculates would’ve taken 13 months using traditional methods. "These are real problems and real engineers," he emphasizes.

Those who think robust is a passing fancy don’t get his vote. But he’s also realistic about its potential. "I don’t consider robust to be a sliver bullet or rocket science, but it is good engineering," says Mr. Billimoria. And it works, he adds: "It’s like a light bulb going on."

Robust’s goal, he underscores, is to "make whatever you’re doing insensitive to variation or ‘noise’ factors-to get designs that will last along time in the field in all environments. The outcome of the robust approach is good durability and quality."

Another major advantage, says Mr. Billimoria, is that robust methods reduce the historical tendency to over-engineer-the practice of concentrating on quality targets in isolation without taking into consideration the whole picture. "This methodology requires a thought-process change. Too much is done in a find-and-fix mode. You want to move the process up front because if you do it right the early stages, you can avoid the fire fighting you typically have to do downstream," he says.

Among still other attributes, GM’s Mr. Wetzel says that looking at engineering and manufacturing solutions for existing components and processes from a robust standpoint can free up money and time to develop high-technology components and methods.

"There’s a wide variation in what people mean by it," concedes Bernard I. Robertson, Chrysler vice president Jeep/Truck Engineering and general manager of Jeep/Truck Operations. "We don’t have a formal corporate definition. We don’t feel we have really widespread awareness of this yet."

Although many engineers surveyed by WAW (see feature p.59) say the idea is not new and will soon fade; top engineering executives think otherwise and subtly suggest that everyone better get with the program.

Because the Big Three are consolidating their suppliers, reducing their numbers and increasingly delegating more engineering-and manufacturing responsibilities to the robust bandwagon as well. And with good reason:" warranty cost-sharing will force robustness to the supplier levels," predicts one executive in WAW’s 1994 engineering survey.

ASI officials warn that suppliers soon will be required to submit analyses of their products based on robust engineering formulas. ASI conducts two-hour "awareness" sessions to explain terminology to supplier companies.

"You can’t do robust without suppliers signed up on board," says GM’s Mr. Wetzel. Adds Mr. Billimoria. "We’ve had several suppliers on our case-study teams, and there’s a vision that this education also will be given to supplier" as they take on more services for the No.2 automaker.

The auto industry isn’t alone in using robust engineering procedures. The philosophy has its converts in diverse industries such as aerospace, appliance manufacturing and electronics.

Proponents have developed mathematical formulas for measuring the "robustness" of individual designs and report cases of dramatic improvements when robust engineering guidelines have been applied to specific problems. But Mr. Billimoria, for one, says statisticians have some difficulty with the concept because it’s not as easily quantifiable as, say longstanding statistical measures such as defects per million parts.

However the results are tallied, robust methods clearly are working. For example, Nissan Motor Co. Ltd. Engineers, in a 1992 paper presented to the Taguchi Method Symposium, said they were able to cut heat-treating time for pieces used in automotive steering and powertrain assemblies from 10 hours to one minute using robust principles.

In Europe, Ford and Pirelli SpA engineers applied the methodology to solve a problem with premature timing-belt failure (see diagram, p52). A new robust design calling for a change in belt composition lowered noise levels-the kind of noise you can hear-and doubled belt life, while allowing the outside supplier to use less-expensive materials at a savings to Ford.

Chrysler’s Mr. Robertson says engineers at the No.3 automaker have their own informal understanding of robust engineering and its value. A key knowing the manufacturing process by which a part or component will be made "in order to ensure minimum variability in the end result."

Perhaps not surprisingly in view of its recent spate of new-product snafus, Chrysler engineers have been looking more intently at variability recently, says Mr. Robertson.

"We find that a greater and greater percentage of the problems that we have in the field are no longer the classic’ or the design wasn’t suitable for the end result of variabilities. In the vast majority of the cases, the design is satisfactory, but some small percentage of perhaps each operation had variability that caused it not to be satisfactory."

Mr. Robertson acknowledges that many people over the years have tried to push design engineers to become more familiar with manufacturing processes. Now, he says, robust engineering brings that effort closer to reality.

"We’re trying to formalize the process by which we all work much closer together," he says. "this causes you to take a fresh look at how you design things.

Mr. Robertson says one idea under study to reduce variability is to take operator adjustments out of production machinery. Parts would have to be engineered to work regardless of which point in a machine’s wear-cycle they were made.

"In the past there’s been something of a tendency to say if the product isn’t satisfactory we just aren’t doing the adjustment right," the Chrysler engineering executive says. "Breaking out of that and saying maybe there’s a whole different way of doing this is an example of robust design." Using the concept, Mr. Robertson argues, is a way to take basically good designs and raise them to even higher standards.

ASI Chairman Lawrence P. Sullivan’s version of the short-form definition of robust engineering is "a product design or process design that is insensitive to the sources of variation downstream."

That includes, he says, manufacturing processes, assembly processes and variations in supplier parts and client use.

"Ford is really driving is the leader right now." Retired Ford engineering executive John Manoogian, whose last job was heading Alpha, was instrumental in developing more traditional engineering troubleshooting methods at the No.2 automaker. He has now become a believer in robust engineering.

" With robust design, you have to change your mindset," Mr. Manoogian says. "You say to yourself, ‘I want to design a new part but I want to forget about how I used to design these part.’ The primary thing robust design is you focus on the function of that part. What do you expect that part to do? That’s the difference."

Traditional effort "were all fire fighting" he says, echoing Mr. Billimoria, while robust engineering approaches deal with potential difficulties earlier in the design process.

A major push behind robust engineering is coming from the speed with which technology is changing. ASI’s Mr. Sullivan points out that engineers can’t wait these days for data from field experience because systems such as antilock brakes are being redesigned too frequently.

"Instead of having your engineers spending 70% of their time fire fighting, you’d rather have them spend perhaps 10%," he says.

Not the least of the challenges in instituting robust engineering ideas into a company, say ASI officials, is making sure that new approaches to engineering problems don’t get short-circuited by senior management tied to traditional approaches.

"You have to work on that, " observes one expert.

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