Gas Analysis and Optimization of Debinding and Sintering Processes for Metallic Binder-Based AM*

Binder-based additive manufacturing processes for metallic AM components in a wide range of applications usually use organic binders and process-related additives that must be thermally removed before sintering. Debinding processes are typically parameterized empirically and thus far from the optimum. Since debinding based on thermal decomposition processes of organic components and the subsequent thermochemical reactions between process atmosphere and metal powder materials make uncomplicated parameterization difficult, in-situ instrumentation was introduced at Fraunhofer IFAM. This measurement method relies on infrared spectroscopy and mass spectrometry in various furnace concepts to understand the gas processes of decomposition of organic components and the subsequent thermochemical reactions between the carrier gas atmosphere and the metal part, as well as their kinetics. This method enables an efficient optimization of the temperature-time profiles and the required atmosphere composition to realize dense AM components with low contamination. In the paper, the optimization strategy is presented, and the achievable properties are illustrated using a fused filament fabrication (FFF) component example made of 316L stainless steel.