A laser beam deflection system for heat treatments in large scale additive manufacturing

Large Scale Additive Manufacturing (LSAM) based on plastic raw material is known for high material output and thus, increased productivity. For an improvement of part properties LSAM is combined with a laser process. Depending on the deposition direction, the laser beam needs to be repositioned to reach the space between two adjacent and consecutively printed strands. Therefore, an optomechanical design is required that allows variable orientation of the laser beam. It consists of a combination of an elliptical, tube-like mirror with an additional, rotatable flat mirror in one of its focal axes. The deflected laser beam hits the second focal axis where the extruder nozzle is located. Thus, > 75% of the nozzle circumference is covered during a laser beam treatment. Both mirrors are individually designed custom-made parts. Its functional verification lays the foundation for an improved additive manufacturing process, which aims to homogenize the component structures to improve the mechanical properties of 3D-printed components

Funktionales Laserfinishing additiv gefertigter PA12-Bauteile

Das pulverbasierte Multi Jet Fusion Verfahren (MJF) hat sich seit der Einführung 2016 in der additiven Serienfertigung etabliert. Einige Anwendungsfelder von MJF-Bauteilen werden jedoch durch eine prozessbedingt körnige Oberfläche mit Rauheiten von Ra > 5 μm eingeschränkt. Ziel dieser Forschungsarbeit ist daher die Identifikation und Charakterisierung von Methoden zur Reduzierung der Rauheit sowie zur Anpassung der optischen und haptischen Oberflächeneigenschaften. Im Mittelpunkt steht die Glättung durch Laserstrahlpolieren (LSP). Damit ist es möglich, den PA12-Kunststoff lokal aufzuschmelzen und die Rauheit auf Ra 5 μm. The aim of this study is the identification and characterization of methods to reduce the roughness and adapt optical and haptic surface properties in order to expand the scope of MJF applications. The focus is set on smoothing by laser beam polishing. With this process it is possible to locally melt the PA12 plastic and reduce the roughness to Ra < 1 μm. Subsequently additional processes, such as metallizing or powder coating, can be utilized in order to adapt the functional properties of the component’s surface

Conceptual Development of a High-Productive Fabrication System for Additive Manufactured Large-Scale Items from Arbitrarily Chosen Plastics

The objective of the research project is the development of a production system in order to create additive manufactured large-scale parts based on arbitrarily chosen thermoplastics. A real three-dimensional additive manufacturing process is going to be realized. It becomes possible to create items under consideration of lightweight design aspects and optimization in strength. The key-technology of the prototype is based on fused layer modeling. An offline tool automatically separates the CAD-model into partial volumes and realizes a multi-axis relative movement between extruder and shell-model. The setup utilizes three extruders to provide a huge variety of material applications and support structures. Special plastic blends are being developed and tested in order to generate items with individually desired properties like hard-soft combinations, colors and locally defined conductivities. Furthermore, it is intended to improve the bonding quality between deposited beads by tempering the extruded paths with a laser beam. Surface improvements, outlining, labeling and the functionalizing of part surfaces are objectives of this research. The final setup will be applicable for prototypes and mass production providing a part volume of 800x800x800 [mm³] and maximum weight of 25kg

Hybride additive Multimaterialbearbeitung: Hochauflösende Hybrid-Additive Multimaterialfertigung von individualisierten Produkten

The aim of HyAdd3D is to create complex additive manufactured components with novel equipment technology whilst simultaneously fulfilling the requirements of the multi-material manufacturing process. The project engages in developing a hybrid procedure solution that is able to process new materials with functional additives. This article describes the HyAdd3D approach and examines the current project status. All relevant findings are summarized to conclude and further developing measures are explained