Engel, an Austrian company that manufactures injection molding equipment, is touting a new "tape sandwich" molding process that should be of interest to designers who work with plastic. The process creates parts with "greater stiffness, despite a more compact part design and less weight, [and] low production costs."

To explain how it works, Engel uses the example of a motorcycle seat base. This plastic part needs to be strong, and the incumbent way of adding strength/stiffness is by adding support ribs, which add both bulk and materials cost.

Engel's innovation is to use what's called UD tape, or unidirectional tape. This is tape that has been impregnated with a resin matrix, adding fibers that all run in the same direction, hence the product name. This matrix provides reinforcement.

What Engel does is stick the tape into both halves of the injection mold for the seat, prior to squirting the molten plastic into it. What comes out of the mold is a delicious tape sandwich, with the UD tape for the bread and the molded polypropylene as the meat.

"Due to the specific mechanical properties of the sandwich structure, we can already meet the stiffness required for motorcycle seat bases with a single-layer UD-tape," explains Franz Füreder, Engel's VP of Automotive & Mobility. "This means that the tape sandwich process requires significantly less energy and simpler production cell technology than conventional fibre-reinforced plastic composite processing methods. At the same time, the production costs drop."

In the specific case of the motorcycle seat, here shown on a motorcycle by manufacturer KTM, the volume of space required for installation was reduced by 66%, and the weight reduced by 26%.

You can learn more about Engel's tape sandwich process here.