Frederik Vogeler

Process Monitoring of Extrusion Based 3D Printing via Laser Scanning

Extrusion based 3D Printing (E3DP) is an Additive Manufacturing (AM) technique that extrudes thermoplastic polymer in order to build up components using a layerwise approach. Hereby, AM typically requires long production times in comparison to mass production processes such as Injection Molding. Failures during the AM process are often only noticed after build completion and frequently lead to part rejection because of dimensional inaccuracy or lack of mechanical performance, resulting in an important loss of time and material. A solution to improve the accuracy and robustness of a manufacturing technology is the integration of sensors to monitor and control process state-variables online. In this way, errors can be rapidly detected and possibly compensated at an early stage. To achieve this, we integrated a modular 2D laser triangulation scanner into an E3DP machine and analyzed feedback signals. A 2D laser triangulation scanner was selected here owing to the very compact size, achievable accuracy and the possibility of capturing geometrical 3D data. Thus, our implemented system is able to provide both quantitative and qualitative information. Also, in this work, first steps towards the development of a quality control loop for E3DP processes are presented and opportunities are discussed.

A novel approach to additive manufacturing: Screw extrusion 3D-printing

This paper presents a novel approach of screw extrusion based 3D printing of thermoplastic materials. In contrast to the well-known extrusion based 3D printing technology Fused Deposition ModelingTM based on thermoplastic filament extrusion, granules are used as raw-material in a plastic processing screw, melting the plastic and depositing it at the required locations. The system is designed to overcome some limitations of the filament based process e.g. the need for a thermoplastic filament as feed material, which needs to be produced with a narrow production tolerance with respect to the nozzle diameter to prevent blocking and especially the limited range of commercially available materials which can be processed. The presented system is controlled by an open architecture based CNC-controller, programmed in such a way that it easily can be adapted and extended with new advanced control systems modules, systems to improve product quality.