Cement-based additive manufacturing: experimental investigation of process quality

The interest in additive manufacturing (AM) of cement-based materials is steadily increasing. Moreover, there is a growing need for higher productivity and part quality. In this study, the impact of the different values of the process parameters on part quality was identified. An alternative process-control strategy was investigated, according to which the width of the extruded path is controlled by the ratio of the extrusion speed over the scanner head speed. To conduct linear- and rotational-extrusion experiments, an experimental apparatus was designed. The significance of the effect of the speed ratio on the part quality was found to be the highest, followed by the extrusion radius, whereas the extrusion speed appeared to be of low importance. Therefore, in linear extrusion, high quality and consistency can be achieved by maintaining the ratio value above 0.8. However, in rotational extrusion, the effect of the radius was additionally considered by calculating the ratio on the outer side of the part, rather than on the centerline. Thus, acceptable quality and consistency were ensured for both linear and curved paths by controlling the aforementioned ratio values.