Effect of flake distribution in mold on the flow during compression molding of unidirectional long fiber thermoplastic flakes

The growth of the use of composites in the industry generates a significant amount of composites waste. The thermoplastic wastes in the form of laminates and pre-pegs accounts for a significant percentage of the total material processed by composites manufacturing industries. These wastes could be shredded into smaller chips or flakes and compression molded into reusable products. Previous experiments have been carried out at the University of Twente in the Netherlands to produce an industrial product from recycled chopped woven flakes [1]. This paper discusses the compression molding process of chopped unidirectional (UD) flakes. The effect of consolidation pressure, dwell time and filling pattern of the mold on the laminates is studied. The paper shows the mechanisms of flake deformation generally observed during the molding process. Surface microscopy and density measurements show the extent of flake deformation and polymer flow. This qualitative analysis will later be used to model the process of flake deformation in melt to predict the mold filling behavior during compression molding of long (6-20 mm) thermoplastic flakes.