The direct strand-deposition process - new methods in compression molding of long-fiber reinforced thermoplastics

摘要

Compression moldign compounds with a thermoplastic matrix, such as glass-mat-reinforced thermoplastics (GMT) and more recently long fiber reinforced thermoplastic pellets (LFT), have been growing rapidly withi nthe last few years especially in automotive applications. Glass reinforced thermoplastics (GRT) offer economic efficiency, a high process reproducibility, short cycle itmes, a stable and high component qulaity and a good recyclability. the direct strand-deposition process is capable to increase the efficiency of manufacturing GRT parts by omitting the step of producing expensive semi-finished compounds. A high flexibility can be achieved by an easy variation of fiber lengths and contents or by using other matrix materials than polypropylene and differnt additives. This paper presents the direct strand-deposition process. Optimum process parameters are determined mainly to reduce fiber length reduction. Mechanical properties, flowability aspects and fiber-length distribution and orientation i nthe part are characterized. With this, the process and achieveable properties can be compared to traditional processing techniques of long-fiber reinforced thermoplastics. This process is also capable to recycle cutting waste and scrap efficiently while maintaining long fibers.