Virtual bead representation and surface roughness evaluation challenges for additive manufacturing material extrusion processes

Additive manufacturing (AM) processes, such as material extrusion, are part of a popular growing technology field; with limited human assistance required and advanced rapid prototyping capabilities, this technology is advertised to have limitless possibilities. The common challenge faced by users is a lack of design control of the surface roughness, which is highlighted by a characteristic stair case layering effect at the boundary. Focusing on material extrusion processes, the goal of this research is to model representative bead shapes, and highlight the surface roughness challenges for assessing boundary-fill regions. Various bead shapes are explored and compared through virtual simulation. Unique material extrusion AM-related issues arise, and it is shown that machining solutions may not provide the desired surface smoothness. This research illustrates that specific physical and virtual assessment tools and standards need to be further developed to convey surface roughness attributes for material extrusion additive manufactured components.