Rapid surface quality assessment of green 3D printed metal-binder parts. (February 2019)

• Record Type: Journal Article
• Authors: Rane, Kedarnath; Castelli, Kevin; Strano, Matteo
• Is Part Of: Journal of manufacturing processes. Volume 38(2019)
• Page Start: 290
• Page End: 297
• Publication Date: 2019-02
• Subjects: Additive manufacturing -- Extrusion -- Feedstock -- Image processing -- Surface quality; Production management -- Data processing -- Periodicals; Manufacturing processes -- Periodicals; Procestechnologie; Productietechniek; Production -- Gestion -- Informatique -- Périodiques; Fabrication -- Périodiques; Manufacturing processes; Production management -- Data processing; Periodicals; 670.5
• DOI: 10.1016/j.jmapro.2019.01.032
• Languages: English
• ISSNs: 1526-6125

Abstract

Highlights: A machine and process for additive manufacturing by extrusion of viscous metal/binder mixtures is described. The effect of process parameters on surface quality of infill layers is studied experimentally. A method for rapid assessment of surface quality of infill via image processing is proposed. Abstract: Mixtures made of a solid metal powder and a viscous polymeric binder are increasingly used in material Extrusion Additive Manufacturing (EAM) processes. The EAM process adopts the relative movement of an extruder head to a build table, to deposit thin strands of the mixture and build a 3D object layer by layer. In this study, EAM process was applied to produce 3D printed square plate-shaped parts of stainless steel 316 L at the green state, i.e. before debinding and sintering. The 3D printing experiments were designed by considering various independent process parameters: extrusion velocity ve, table velocity vt, layer height h and hatch spacing Da . The surface characteristics of as printed (green) square plate-shaped parts were investigated by a rapid, high-resolution optical imaging technique. The obtained images were analyzed to model the effect of the process parameters on the surface uniformity Ui and space filling Fi . The proposed methodology can be also used as a process monitoring technique. The study has demonstrated that the layer height h has the most relevant effect on the infill quality and should be set at a low value for good quality. However, a combination of the other parameters can be found that yields a compromise between infill surface quality and build up rate.