Headquartered in Auburn Hills, MI, Guardian Automotive Corporation is one of the world's largest manufacturers of float glass and fabricated glass products. It is also an international supplier of exterior vehicle systems. Its Warren Automotive Trim plant, located in Warren, MI, designs and builds the primary injection molding tooling for making parts for Guardian Automotive. More than 120 plastic injection molding machines with tonnage capacities ranging from 100 tons to 3,600 tons, are operating at seven locations throughout North America. Half of its production is decorative trim products and other half is glass applications for the OEM and Tier One markets.

Russ Napp is the Director of Tooling there and has more than 25 years' of experience in the automotive trim business. He and his colleagues have relied on Moldflow simulations performed by CAE Services (Batavia, IL) for the last several years. In fact, last year alone, nearly 20 analytical studies were performed by CAE Services for Napp.

He says that since much of their work is related to decorative parts such as automotive grills, cosmetic issues are important. "Moldflow filling analyses are good predictors of knit line locations. The Moldflow fill, warp, and cool simulations allow us to talk to our customers about appearance expectations prior to building a mold. If knit lines appear, we can demonstrate their locations and discuss alternatives with customers. The simulations help me in the approval process," says Napp.

Cosmetic assistance
Recently, Moldflow flow, fill, warp, and cool simulations were used in the design of a chrome grill that fits in front of a car radiator. Napp adds, "Since the part is shiny, any defect in the molded part would appear quite handily through the chrome. So the use of Moldflow to address possible cosmetic issues was crucial. In addition, manifolds for delivering the plastic to the part are quite expensive because they are comprised of many drop features. In terms of processing, grills are quite complicated. If we obtain knit lines in the wrong locations or at places that our customer does not approve, replacing a manifold can be financially devastating – costing $50,000 or more. We use Moldflow to avoid that situation and build confidence that our designs will be successful."

Napp says they use Moldflow simulations not only to identify knit line locations, but the software also provides expected injection pressures "Moldflow analyses tell me if we are going in the right direction and whether the gating scheme in a part is reasonable. They provide sufficient information to confirm that our expectations for a part will be successful. However, it's important to note that you have to have the engineering and process knowledge to be able to understand the simulations," Napp adds.

Project savings
For these reasons, Napp says using Moldflow for complex parts such as grills is invaluable. While he does not have a specific quantifiable measurement for the recent grill project and using Moldflow, Napp says he lauds the time and money not spent on possible downstream problems if the software was not used prior to production. "We use Moldflow simulations to avoid unwanted costs," Napp explains. Regarding the recent grill project, Napp and his team eliminated trial and error and manifold replacement expenses. And, the job finished on time. "Once you experience the pain associated with unexpected expenses, you start to look for a tool that helps you avoid those issues."

He solicits help from CAE Services because the firm offers excellent engineering expertise. In addition, CAE Services helps Guardian Automotive establish continuity regarding its Moldflow use. "As you acquire and build Moldflow knowledge, you begin to understand the correlations between similar parts," adds Napp. "We have consistency regarding analyses and narrowed the number of people who are using the technology. This strategy has provided us with better results."

For more information about CAE Services, go to www.caeservices.com. To contact the writer, write to Email Contact.