Investigation of filler share influence in highly filled carbon polymer compounds (> 50 vol%) with Material Extrusion (MEX) based Additive Manufacturing

Today highly filled carbon compounds with fractions of carbon derivates like graphite, carbon black, etc. by more than 50 vol% are used in special applications with the need for high electric or thermal conductivity at high chemical resistance. Though actually being processed only by conventional manufacturing technologies the additive manufacturing of these highly filled carbon polymer compounds can enable new possibilities in design, prototyping and manufacturing on demand in these fields of application. Recent studies either concentrate on additive manufacturing of compound composites with low electric conductivity or high mechanical stability for example with carbon nanofillers. This paper differs from existing literature that it investigates the electric conductivity in special of different carbon compound formulations with challenging filler share rates of more than 50 vol% and up to 80 vol%. This work also shows material behavior, influence factors and challenges in the use with material extrusion. The results of investigations lead to new insights and conclusions for product design and material processing. The process shown in this work has the potential for application in industrial additive manufacturing of carbon products like graphite bipolar plates used in hydrogen fuel cells, tools for complex thermal forming processes or conductive housing parts for measurement applications. This leads to innovations for existing or new fields of application for highly filled carbon compounds with filler fractions above 50 vol% due to the potential of additive manufacturing in general.