Automotive goes big with three-platen system

When Volkswagen late last year added a 3200-metric-ton molding machine to the 110 presses already in its Braunschweig, Germany factory, it was a major change in scale. Previously, the largest machine there was 800 metric tons. Purchased primarily to produce the largest dashboard components for the luxury model of the company's newest Multivans, this machine also bucked the trend toward two-platen technology. VW selected a three-platen Battenfeld HM system.

Ralph Sundermeier, who has been head of VW's plastics technology section in the plant since the beginning of this year, explains the choice. "From operating 110 injection molding machines of various brands and ages, we have been able to gather a considerable amount of experience. Our experienced operators know their priorities: Uptime, precision, and service are at the top of the list. We were looking, above all, for sturdiness and simplicity of operation, and we are confident that this is precisely what the Battenfeld three-platen module has to offer." (Battenfeld recently introduced a two-platen clamp for the HM Series but continues to support three-platen technology as well.)

Pioneering New Products, Technologies
Plastics Technology, which is one of seven business units at Volkswagen's Braunschweig plant, last year made about $72 million in sales with 650 employees. Products include interior parts such as seat components, linings, dashboards, motor and underbody parts, and exterior surface components. The products are used in such VW models as Golf, Polo, Passat, Multivan, and Caravelle. Platform components also go to other VW Group members such as Audi, Seat, and Skoda.

According to Sundermeier, the unit's approximately 450 products are typically the more sophisticated components that need innovative process technology. "Once a technology becomes standard in the market," he says, "we find it increasingly difficult to remain competitive." Production then goes to outside suppliers and the group moves on to new challenges. There are a few parts made in-house for strategic reasons, and these are also high-tech. Braunschweig manufacturing units must bid for production orders on equal terms with external suppliers. "We will not get any orders unless we offer a very convincing price-performance ratio," Sundermeier says.

Luxury Model Dashboards
With orders increasing at the Braunschweig facility over the last few months, Sundermeier says there are plans to increase the workforce to 700 employees by 2004. A current project that is particularly influential in the expansion is the dashboard for the luxury version of the VW Multivan T5 to be launched in spring 2003. These will come exclusively from Braunschweig.

The dashboard body consists of three moldings welded together. The top and bottom parts are connected by the air duct. Various other components such as a glove box, exhaust devices, air ducts, and valves that are also manufactured in Braunschweig are assembled into the larger structure. The dashboard assemblies are delivered to the Multivan plant in Hannover where they are further processed into cockpits before being fitted into vehicles.
The production system is an integrated cell that can handle all three molds for the large PP or EPDM dashboard components. Battenfeld designed the complete installation including robots, grippers, an inverted transportation line with cooling station, magnetic mold clamping system, and other ancillary equipment. The hydraulic HM 32000/19000 injection machine has an electric plasticating unit for continuous processing. A Suhling linear robot removes parts from the mold. In the case of the dashboard top, the robot transfers it to the inverted transportation system for cooling. Since this particular component has a thin wall section combined with a very long flow length, VW uses sequential valve gating.

To accommodate the largest component, again the top part of the dashboard, Battenfeld extended the maximum mold height adjustment by 600 mm (23.6 inches). There is a tiebar removal device to make fitting the 40-ton mold as easy as possible. Another feature designed to make work easier is the QMC magnetic clamping system from Stäubli. "This system gives us more flexibility than a fast clamping system, since it also accommodates smaller molds," explains Sundermeier. He says it comes as close as possible to a universal clamping system. The large Battenfeld machine includes several cooling circuits, a hydraulic system for valve gates and core pulls, and other features that Sundermeier says give it the flexibility wanted for future large-dimension parts and molds.