GM Powertrain

Design verification at a fraction of the cost

The Problem
GM Powertrain Group in Pontiac, Michigan, an engineering division responsible for the design and manufacturing of automobile engines and transmissions, had to design a complicated engine cylinder head. Because design duties were divided among design teams, each of whom were assigned a specific section of the single-piece cylinder head, communication was essential to orchestrating the final design successfully. And because of the complexity of the cylinder head's internal cavities, a two-dimensional drawing was not adequate to visualize how the various sections would interact. Three-dimensional models were absolutely necessary to validate the intricate features and to refine the individual sections for an optimal design.

What's more, the design division had to communicate to a number of other departments responsible for the manufacturing of the final product, most of whom were unfamiliar with the two-dimensional CAD medium, but whose input early in the process was necessary. "For both design and manufacturing to understand the complexity of the part early on, a three-dimensional model was a must," says Dave Rogers, Design Supervisor for GM Powertrain Group.

Alternative Solution
Before receiving their Actua 2100, GM Powertrain had no choice but to send designs out to the manufacturing division for tooling or rapid prototyping, a more costly and time-consuming means of producing a three-dimensional "visualization" model. "We were spending valuable rapid prototyping dollars for non-rapid prototyping applications," explains Rogers.

The process took five days from the time of request until the three-dimensional model was in the designer's hands -- valuable time in GM Powertrain's fast-paced design environment. With the design team making changes on a daily basis, the model was obsolete before it arrived. Since each half-scale model cost around $2300 per iteration, GM Powertrain needed a faster, more cost-effective method of producing three-dimensional models. Actua fully met their expectations as a three-dimensional concept modeler and provided an alternative to their design dilemma.

With an Actua 2100 located within the design environment, each design team was able to produce three-dimensional verification models of their assigned section at their own convenience. Individual "slices" or sections of the cylinder head could be printed out and fit together like a loaf of bread. Refinements could be made to specific features and examined without producing an entirely new model. All this could be done easily, and at a fraction of the time and cost of conventional methods.

A Magnitude of Savings
With the on-site Actua 2100, GM Powertrain estimates they were able to produce a half-scale model in just twenty hours and at a cost of only $120. Quite a savings compared to the five days and $2,300 required for traditional methods. "There is a magnitude of difference in using the Actua to produce three-dimensional models -- we've gone from days to hours and from thousands of dollars to just over a hundred," enthuses Rogers. In addition to the quantifiable time and money savings, GM Powertrain has experienced what Rogers calls, "soft dollar cost savings". Using the Actua, designers can make decisions faster and iterate design changes more quickly, saving time and energy which translates into dollars down the line. With a three-dimensional model in hand, designers can identify costly design flaws early in the design process before costs escalate.

Actua provides up-front communication between the designers and downstream users -- most of whom do not get involved with the design process until there is a physical part available. Other engineering disciplines can participate in the design process earlier, allowing them to give their input sooner so design changes can be made to improve the overall manufacturing process.

Designer's Neighbor
Located at the Powertrain Advanced Engineering facility in Pontiac, Michigan, the Actua 2100 is situated next to the CAD area among a collection of printers and plotters -- a convenient neighbor to twenty-six workstations. Jobs are submitted to a prioritized job queue located on the group's computer network, where they are prioritized by three lead designers who make sure the Actua stays busy, running over 18 hours a day. Shorter jobs are completed during the day, and longer jobs are run overnight and on the weekend, maximizing the efficiency of the machine. By providing designers with the opportunity to quickly produce models within the design environment, Actua has opened new doors for the interaction between the design and manufacturing disciplines, providing the ability to refine the design process and speed products to market.