On a virtual path to perfection

  • 08-Apr-2009 03:37 EDT
Audi uses simulation of the heating-up process after painting to ensure that every part of the chassis has reached the critical temperature level by the end of the process. This serves to optimize process design and potentially to improve the design for production.

Over the last six to eight years, the complex business of digitally planning, simulating, and integrating vehicles, processes, and production sites has evolved from what once was considered a new approach to what is now a practical reality. While the diverse landscape of digital factory software (and the different data models within the companies using these tools) makes data consistency a challenge, individual tools are now widely used by automakers such as Audi and Ford to optimize and evaluate vehicle manufacturing long before the start of production.

“The digital factory links product development and production,” said Dr.-Ing. Uwe Bracht, Professor and Head of the IMAB Institute at the Technical University Clausthal, Germany. This is driven by strong economic needs, according to Bracht, who rounded up the current status of tools and application during the 5th Digital Factory Congress, held at Ingolstadt, Germany, early in 2009. “Today," he said, "we cannot afford months until we reach the maximum production volume. Digital factory planning helps to reduce the time to market and the time to volume.”

Virtual prototyping as part of an integrated development process translates into fewer prototypes, according to Bracht. “While there are limits at the detail level—for instance, in modeling the springback during sheet-metal forming—digital manufacturing planning delivers savings. From our working with OEMs, we estimate that there are 70% less planning problems, 30% less planning time, and 3 to 5% less manufacturing cost. The latter equals a substantial amount of cost per unit.”

Bracht considers Audi to be among the global leaders in digital factory technology. The OEM has grown dramatically on all levels since 1995, and in 2008 sold more than a million cars for the first time. The OEM is now in its 100th year (founded in 1909) and keeps coming up with new models. The upcoming A1 is an example of this proliferation. To master the challenge of making more cars economically and in high quality, Audi has been very active in supporting planning processes by digital tools.

Dipl.-Ing. Arne Lakeit, Vice President of Manufacturing Engineering at Audi, said: “We have replaced the sequential approach by concurrent engineering. In product development and production planning we are working in parallel. Design for production is important to us. Among other things, our software tools enable us to make sure that a product can be integrated into an existing, highly automated line.”

This manufacturing flexibility is gaining further importance during the economic crisis. At Audi, for instance, the A4 Avant and the Q5 are made on the same chassis line in one standard process and with common tools and fixtures.

"There is no way of doing this without digital factory software to plan the tools and fixtures, because the two cars have very few common chassis parts," said Lakeit, who has been heading Audi’s planning since 2004. Instead of using dedicated lines, digital factory planning serves to increase model flexibility to buffer the upswings and downswings in individual model demand.

Doing this is not so easy when the laws of clocked production are considered. If several models are manufactured on the same line—as is the standard process at Audi—the number of activities per worker may vary from model to model. This can either lead to unwanted time spreading or make it necessary to integrate more activities per worker depending on the model. Digital production planning seeks to avoid problems of this type from the start.

“It is a trade-off between design priorities and manufacturing priorities, which we tackle in discussion between our development engineers and production specialists. In the end, every decision has to contribute to product quality as perceived by the driver,” said Lakeit. “If there are product-related production steps that cannot be done in an automated process, we will fight for a change.”

Knowing that “traditionally there is trench between vehicle development and production experts," as Bracht put it, concurrent engineering has to overcome mental obstacles.

Asked for some bottom-line figures, Lakeit estimated that the digital process chain from product development through production and up to service saves the OEM 30% of cost along the process chain. “If you consider the additional IT investment of around 10 to 15% for this front-loading, we are looking at savings in the magnitude of around 15%,” Lakeit said. “But then there are things you simply cannot do without digital planning tools. There is no way to assess and evaluate a cockpit manually 2.5 years prior to the [start of production], for instance. Our current level of detail and quality would be unachievable without consistent, software tools-based processes.”

Ford Motor Co. has made digital pre-assembly an integral part of its global One Ford approach. As the OEM seeks to reduce the overlap in its vehicle portfolio, it is integrating R&D centers and production sites more closely, according to Dipl.-Ing. Achim Weiss, technical expert, process driven product design, in Cologne. “Our product and manufacturing development experts jointly develop the car,” he said.

Until 2012, Ford seeks to reduce its vehicle platforms by 40% and to base 70% of its total volume on just eight platforms. This will translate into new manufacturing requirements. “A globally harmonized product development process is mandatory for all product and manufacturing development centers worldwide,” said Weiss.

An essential part of this globally harmonized product development process is a final digital data judgment before product release.

“The product is continually checked and has to pass several gateways before release. Worldwide manufacturing engineering locations work very closely with product engineering and report their findings back into a joint digital pre-assembly process,” Weiss explained. “This process is tuned to address the engineering needs of a global enterprise. The systematic verification of the product against engineering, manufacturing, and process requirements enables reporting of a consistent, up-to-date health status to the global management team at any time throughout the development process.”

The first model delivered under the One Ford strategy is the new Fiesta global small car, destined for the U.S. in 2010.

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