Manufacturing Continuous Fiber‐Reinforced Printing Filaments: Development of a Post‐Consolidation Unit

A novel, temperature‐controlled post‐consolidation unit is developed to test its potential to improve the melt impregnation process used to manufacture continuous fiber‐reinforced filaments for additive manufacturing of high‐performance thermoplastics. Preliminary laboratory characterizations have identified Hexcel HexTow AS7 and Arkema Kepstan 6004 as suitable dry carbon‐fiber roving and thermoplastic matrix material, respectively. Filaments are processed by melt impregnation with varying parameters (e.g., different temperatures), as well as with and without the post‐consolidation unit. A thermographic camera is used to monitor the process and observe the temperature distribution of the filament during post‐consolidation. The filament quality is determined by a 3‐axis measurement device (filament diameter), micrographs, and X‐ray microscopy. The test results show that the temperature of the filament drops below the glass transition temperature over a production length of less than 100 mm when cooled by air. Using the post‐consolidation unit keeps the filament above the glass transition temperature of the matrix (160 °C) for a production length of 550 mm, allowing compaction by the integrated grooved rollers. The test results show that post‐consolidation reduces defects, improves the roundness of the filament cross‐section, and minimizes diameter variation.