KraussMaffei delivers large lightweight components with a class-A surface

"The good mechanical properties and the premium-quality surfaces commend the Long Fiber Injection procedure for large-format components in many markets, and especially in the automotive and commercial vehicle industry to meet the increasing demands of the CAFC (Corporate Average Fuel Consumption) program for a lower fleet consumption," explains Paul Condeelis, VP Business Development at Romeo RIM. "KraussMaffei has been a competent partner and the only market player able to meet our requirements."

With the enormous dimensions of approximately 2.5 x 2.1 m (8' x 7') and an area of over five square meters (56 sq. ft.), the complete two-piece roof weighs less than 23 kg (50 lbs.) and meets all requirements regarding flexibility, good durability, low weight, and cost-effective manufacturing. Another contribution is the option for functional integration on the rear side, where the dome and ribs are attached.

The heart of the system – the oversized mold carrier

At the center of the system is the largest mold carrier built by KraussMaffei to date, with a mold clamping area of 3660 x 3660 mm (12' x 12') on the molds with weights of up to 40 US tons (36 metric tons). The mold carrier with the dimensions 22 x 9.5 x 5 m and a clamping force of 400 tons is equipped with a "two-shuttle system," which brings two bottom parts of the mold into the mold clamping unit in alternation. While the Long Fiber Injection process and the reaction time are running in one mold, the second mold can be de-molded and be prepared for the new process. Every 9 to 10 minutes, therefore, one of the two elements for the complete roof is formed in alternation. For precise component thicknesses and reproducible processes, the mold carrier is equipped with an hydraulic 4-axis parallelism control, which also ensures parallel closing of the molds for asymmetric components or off-center mold clamping. "The new mold carrier will enable us to produce, for instance, even larger exterior body panels for all of the markets we service like the agricultural and heavy truck markets and to do it in a cost-competitive way," explains Condeelis.

Expertise for machines, procedures, and automation from a single source

Two industrial robots, each of which are equipped with an LFI mixing head of the latest generation, are moved over the mold to put in the LFI mixture. Beforehand, two additional industrial robots can be used to put a layer of paint (In Mold Painting) and a barrier layer into the bottom mold, which prevents the fibers from standing out on the visible side. Consequently, completely painted components with excellent mechanical properties and premium quality surfaces are manufactured in a single pass. "To prevent problems from arising in the areas where the paint evaporates, the shuttle system is carried out there with explosion protection," says Cord Hagenmeyer, project manager at KraussMaffei. "Here, the combined expertise from process engineering and mechanical engineering come to fruition. Since all components were manufactured at KraussMaffei, all requirements are able to be implemented quickly and safely."

Even at such an enormous size, the operability does not fall short. This is provided for by a swivel device on the movable upper mold clamping platen. When a mold carrier is completely opened, the upper plate with the top mold can be swiveled out by 90°