The twin screw extruder is used for continuous compounding, preparation and processing of polymers. The polymer processing takes a severe interest in the modification of polymers with carbon fibers and carbon fiber recyclates. In this correlation, the recycled carbon fibers are production residues (e.g. in the automotive industry). The steadily growing demand for fiber-reinforced thermoplastics is based on their significantly improved physical and mechanical properties. In addition, new laws (e.g. EU Waste Framework Directive and End-of-Life Vehicle Ordinance) regulate the recycling of the carbon fiber residues. Due to legal requirements, alternative disposal methods for fiber composites will become indispensable in the future. The production of compounds from a thermoplastic matrix and fiber recyclates can represent this alternative disposal method. However, the incorporation behavior of the recycled fibers are not so well analyzed. Within this paper, the influences of the process parameters and screw configurations on the fiber length decrease along the screw for recycled fiberballs are investigated. The aim of the work is the description of the the influences on the fiber degradation and the determination of the mechanical properties of the produced compounds.