Executing Organisation: AiF Projekt GmbH, Program: ZIM – Central Innovation Program SME of the Federal Ministry of Economic Affairs and Energy
In this project, an efficient laser-assisted post processing method for additively manufactured components made of thermoplastic materials was developed. The aim was to significantly improve the functionality of the additively manufactured plastic components and to approximately achieve the quality of injection-molded components with regard to mechanical properties, dimensional accuracy and surface quality, while at the same time the advantages of additive manufacturing concerning freedom of design and economic and ecological efficiency with small lot sizes are maintained.
The process uses a scanning CO2 laser which can be switched between pulsed and continuous emission mode. The pulsed laser beam allows the subtractive processing of additively manufactured components by laser ablation in order to remove geometrical deviations like waviness or steps. Micro roughness can be reduced by laser polishing (remelting) using continuous wave CO2 laser radiation.
The results show that laser polishing with continuous wave CO2 laser radiation can reduce surface roughness by up to 50%, even at high angles of incidence (up to 60 °). By laser ablation using pulsed CO2 laser radiation, the component tolerance can be significantly improved by selective ablation with minimal ablation depths per pulse of about 25 μm. The ablated surfaces show up to 65 % reduced surface roughness (see figure at left), resulting in a significant improvement in mechanical properties (see figure at right) with complete processing of the components.