But, "Fit at Assembly" has been banished from the lexicon of at least one tooling supplier because the concept, and the time-honored process it represents, are no longer adequate to meet the needs of today's automakers. At Peak Industries in Dearborn, Mich., the new watchwords are "Design For Manufacturing" and "Shop Engineering," two concepts made possible by an innovative, proprietary approach to 3-D modeling that defines a new process for engineering and manufacturing assembly tooling.

No Time For Old Methods

"With our customers cutting months and years out of their product development cycles," explained Jeffrey Miles, engineering supervisor, "there just isn't time to build assembly tools the old way. Today, they're expected to arrive at the plant at the same time the first sheet metal and sub-assemblies do, and they had better work -- or else. To survive in that kind of environment, we've developed new procedures for engineering and building assembly tools.

"3-D modeling as the foundation for simultaneous engineering and a streamlined internal manufacturing operation was clearly the way to go," Miles continued, "but the cost of the big name systems was more than we cared to pay. We decided there had to be another way, so we worked on the problem until we developed a solution.

"The 3-D modeling capability we've developed is built around a customer integration of CAD, surfacing, rendering, animation, and translation capabilities from a variety of sources," Miles noted. "It's all readily available and in widespread use. But we've made it all work together in a system that mirrors the capabilities our customers have. What makes our system different is the integration, and that's our own development."

Simultaneous Engineering With A Twist

By basing the engineering and manufacturing process on customer- supplied electronic data, rather than paper drawings or hard models, Peak is able to enter into truly interactive simultaneous engineering projects with its large automotive customers. More often than not, that means Peak first engineers and then builds assembly tools for components that don't even exist outside the customer's computer and Peak's 3-D models. It also means both Peak and the customer can examine a wide range of design possibilities before arriving at an optimum solution.

A case in point is an instrument panel (IP) installation tool Peak designed and built for a major U.S. automaker recently. The tool is designed to center the IP inside the body, providing equal clearance on both sides. It's a simple sounding task that has presented automakers with a persistent challenge for many years.

IP centering is a very common component of "fit and finish" ratings performed by a number of consumer magazines and other organizations every year. The problem is that the stack-up of body assembly and IP tolerance often approaches 1/2 inch, which is enough to cause interference with door panels, and is noticeable to the consumer.

Because the tolerance stack-up is unpredictable, simply locating the IP from the centerpoint of the supporting crossmember does not assure precise centering in the finished passenger compartment. Even with special training, skilled installers are not able to consistently center the IP because the body in white provides no reliable visual indicators.

Stepping Up To The Challenge

The automaker approached Peak with the challenge, and proposed a multi-model year development project using a current model as a prototype testbed, with a fully implemented solution scheduled for a future model year production to coincide with a major interior re-design. Peak accepted, and decided that the multi-year nature of the project made it ideally suited for its 3-D model based system.

Peak's first challenge was to build a 3-D model of the IP from the (dozens, hundreds?) of individual component parts listed on the customer's bill of materials. This was not as simple as it might sound, since the datasets for the various components resided with a variety of different groups within the customer's organization.

"We talked to interior designers, ducting engineers, wiring systems people, radio and electronics groups, and many other sources before we got all the data we needed," reported Miles. "But our perseverance paid off and we ended up with a 3-D model of the IP and its associated structures.

More Than Just An Engineering Tool

"In fact," Miles added, "we've found that our models are excellent tools for group meetings to thrash out design problems. We've had as many at 15 customer engineers from various disciplines in one room using a large-scale projection of our model to evaluate the impact of future design changes on all the systems that go into and work with the instrument panel. That sort of thing really accelerates a simultaneous engineering project."

As the IP model progressed, Peak began sending details to its fabrication shop for machining. By the time the final assembly drawings for the tool were completed, the tool was built.

"We literally built the whole tool before we generated the assembly," Miles noted. Everything fit, because everything came from the same set of customer data. And, when the tool was delivered to the plant for pilot testing, it worked the first time it hit the floor. "It's still working," he noted with pride.

Building On Success

With that success under its belt, Peak and the customer began improving the design to incorporate the lessons learned in a production environment. Future production tools would be more difficult to design because the IP was not only changed, but came in three distinct variations for different models built on the same platform. It was also considerably larger than the one variation of the IP, leaving only 4 inches (101.6mm) of working space for the assembly tool.

Changing The Car To Make The Tool Work Better

As the project developed, Peak modified its model to incorporate the evolving changes to the IP, and then returned tool data to the customer for evaluation and further modification. During this process, Peak identified an opportunity to improve the installation process if the customer would modify his process to supply a pair of locating holes to assist the tool in centering the IP. After much discussion, and many iterations and simulations using Peak's 3-D model,the customer agreed to include the new locating holes on the subsequent model year body.

"This revision to the customer's design is just how simultaneous engineering is supposed to work," Miles said, "and its a perfect example of what happens when it's done right. I think the fact that we could use the 3-D model to look at all the possibilities and predict the results of design changes was the key to making it happen."

Supported by the confidence developed during the pilot project, Peak is building more tools using the same methods. Each tool is released for manufacturing as it is finalized, well before the customer's product is made.

Shop Engineering

"One of the reasons this approach works for us," Miles explained, "is that all of our designers and engineers have hands-on experience in the shop. They've run machine tools and built assembly tools themselves. As a result, their designs are what we like to call 'shop engineered' which means they're easy to manufacture and easy to assemble. "Not only does that save us time and money in the fabrication end of things," he continued, "it also lets us compress the build cycle. 'Fit at Assembly' is something we don't do anymore, and neither do our customers."

Peak Industries has been a supplier of custom automation and assembly components and special machines and systems for the automotive and other manufacturing industries since 1966.