Fibers are one of the most important reinforcement materials when it comes to polymers. Combining fibers with polymer resins significantly increases the polymer material's mechanical properties. On account of their relatively light weight, fiber-reinforced polymers are often used when designing lightweight components found commonly in the automotive or airspace industry.

While fiber-reinforced polymers traditionally consist of thermosets, there is an emerging industrial trend toward using thermoplastic matrices. On account of their chemical structure, the latter class of polymers becomes moldable at certain, higher temperatures. In regard to the production process, these characteristics are advantageous, including a higher degree of automation and potential recycling material.

In the “Smart Extrusion” machine hall at the LIT-Factory, thermoplastic tapes are produced and reinforced with unidirectional-oriented (UD) continuous fibers. A haul-off unit located at the end of the process line pulls continuous fiber rovings (e.g., glass or carbon fibers) from creels that are placed on a strand. Before entering the extrusion die, the rovings are threaded through a spreading unit to force the filaments to distribute uniformly over the width. The rovings are then pulled through an extrusion die where they are impregnated with a thermoplastic polymer melt (e.g., polypropylene or polycarbonate) and shaped. During the downstream processing steps, the fiber-reinforced thermoplastic tape is calibrated, cooled down, and coiled.

Bernhard Löw-Baselli understands more about UD Tape Extrusion