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General Motors
 Stereolithography Provides a Symphony of Benefits
At General Motors, the world's largest user of stereolithography, what began as a grass
roots push has spread like wildfire throughout the corporation. Penetrating most of GM's many divisions, rapid prototyping
is becoming a necessary tool in the critical race to be first to market.
The drive to be first to market accelerates. Executives demand higher profit margins.
Consumer needs and wants change almost overnight. General Motors, like auto makers
the world over, faces the daily challenge of decreasing product cycle time, increasing
profits and meeting the needs of consumers before they're even expressed. Dr. Susan
Smyth and Steve Willis, of GM's Manufacturing Center, which is the Rapid Prototyping
Center of Expertise for NAO (North American Operations), tackle this challenge with vigor. Through the use of rapid
prototyping (RP) methods like stereolithography (SL), they have found a tool to ignite GM's
success - reduce the time it takes to prototype a vehicle.
Road Blocks
Time has never been a luxury for auto manufacturers. Within all vehicle programs, a
driving need is to have many prototype components ready at the right time. "The room
for error is small," states Smyth. "We don't want to create a bottleneck because some of
the components are ready, but are waiting for additional components to be finished. We
can't wait!" With RP technologies like SL, they don't have to. Throughout the company, the
goal is the same - produce high quality, innovative parts at lower cost in less time. At GM,
more and more often, the means to achieving this goal is RP. Successes spread like wildfire.
"When designers and engineers see how it helps achieve our goal, they become good repeat customers for RP project."
- Tom Greaves,
Advanced Manufacturing Engineer
Delphi Interior and Lighting Systems
(a components division of GM)
Tuning Up
At Delco Electronics, GM's automotive electronics subsidiary, the engineers, given a
chance to showcase their talents, orchestrated a masterpiece: the Maestro project.
Designed to harmoniously blend an advanced Audio System, a hands-free cellular phone,
Global Positioning System (GPS) navigation, Radio Data System (RDS) information, and
climate control into a completely integrated driver control system, the Maestro was to be a
technological tour de force. With many uniquely-shaped push-buttons, two active-matrix
LCD screens and a local area network allowing for future expansion, the Maestro had only
one possible sour note: time. Delco Electronics realized that only 6 months remained
before Convergence '94, the world's premiere automotive electronics conference. Held
only once every two years, Convergence was the critical launching point for Maestro.
Stereolithography Sets the Tempo
Working together with Modern Engineering, an engineering service company located in
Michigan, Delco Electronics developed the first renderings and concept drawings for the
Maestro project. It soon became apparent that the team was going to have to buy time at
the front end of the project in order to have sufficient time to integrate the complex
electronics and still make the deadline for Convergence.
Having an instrument panel with its myriad of working push buttons early in the design
cycle was critical. Unfortunately, the very large number of buttons meant a correspondingly large number
of rubber molds, with all the delays associated with the conventional molding process. From the
stylist's concepts, Modern Engineering manually machined models of each button face for customer
design approval.
Once approved, the machined models were laser-scanned, generating the necessary CAD
data for the creation of SL models. The CAD data, consisting of the backside geometry of
the buttons, the housing and its mechanical circuit board requirements, was then delivered
to GM's NAO RP Center. The final prototype buttons needed to be accurate enough to
ensure proper fit and function, as well as be translucent, so that they could be backlit.
Orchestrating Results
Working with an SLA 500 system, John Bolognino, Supervisor at GM's NAO Center of
Expertise for RP, modified the original button design, flattening the underside of the button
face to eliminate "stair-stepping" on the inside surface. With this modification, the buttons would not betray their SL origin, even when backlit.
Typically, machined models would have been created from the CAD data and then used to
generate rubber molds. From those molds would come the individual parts necessary for
benching each unique button. However, the SL models supplied by GM were so accurate
they could be finished, painted and installed in the actual prototype vehicle, eliminating
the need for rubber molds altogether. According to Brian Davert, Project Manager for
Modern Engineering, "The SL process allowed for continuous design development of a
functional part, delivered within hours of design direction."
The result? In less than four months, Delco Electronics had a complete, functional
instrument panel, with all 108 buttons built in SL directly from CAD data. "By using SL, we
bought ourselves two months to complete the electrical work," says Nancy
Edenborough, the Advanced Development Engineer responsible for the Maestro project. "This was a
crucial project for us, a showcase. It had to be done in time for Convergence. SL allowed
us to accomplish that." Launching Maestro at Convergence '94 solidified Delco Electronics'
position as an automotive technology leader and a first-class supplier to the world wide
automotive industry. Fully functional, and installed in a stock high-end European luxury
automobile, Maestro provides an integrated control system completely in sync with today's
automotive consumer.
Sharing the Wealth
Designers and engineers from dozens of divisions throughout GM share stories like these
at their Annual Internal RP Convergence. Hosted in 1991 by Smyth and Greaves, the
conference has met with amazing success. Because participation is restricted to GM
employees, engineers and designers are allowed to share real numbers and statistics
which makes for solid, hard-hitting presentations.
With a goal of educating and informing, the conference continues to thrive. Over the last 5
years, as GM designers and engineers come to recognize the significance of RP, the
attendance has grown. Distinctively diverse application stories are now shared by multiple divisions within GM.
Getting Physical
As GM goes through each new model year and each new design program, more and more
uses for RP appear. As designers and engineers communicate with each other, offering
suggestions and solutions, more work flows into the RP Departments - much of that work geared toward enhancing future communications.
Three-dimensional models establish a synergy in product development. They eliminate
some of the communication barriers between designers and engineers, helping everyone
speak the same language. More than half the time, upon evaluation of a physical part,
designers find areas to improve. Things that couldn't possibly be seen on a two-dimensional CAD
screen. SL reduces costs significantly by allowing designers to perform multiple iterations, perfecting the part before a nickel
is spent on tooling. Additionally, physical models act as a communication tool between GM and their vendors,
minimizing confusion regarding specifications and allowing vendors to make suggestions
regarding better methods of manufacturing. Supplier quotes are more accurate, often less
expensive, and guesswork eliminated. RP methods like stereolithography have proven
themselves time and time again at GM. From power train prototypes to interior lighting
systems and from interdepartmental communications to vendor quotes. Greaves sums it
up - "Nothing takes the place of having a physical part to work with."
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