Theoretical modeling and experimental study on the dimensional shrinkage and surface roughness of metal material extrusion 17-4PH products

Purpose The purpose of this study is to set up the theoretical model for predicting the dimensional shrinkage and surface roughness of metal material extrusion (MME) additive manufacturing 17-4PH parts, as well as carry out the experimental validation and sensitivity analysis. Design/methodology/approach With the porosity and gravity taken into account, the dimensional shrinkage model of MME sintered parts is set up based on the thermal viscoplastic constitutive model. The surface roughness model of MME sintered parts is established by integrating the shrinkage mechanism and bonding neck formation theory during ME shaping. Subsequently, a series of experimental tests are performed on the samples to obtain the measured data and then used to validate the proposed model. Findings It indicates that the theoretical models proposed in this study can give reliable predictions in the dimensional shrinkage and surface roughness of MME sintered parts. The sensitivity analysis shows that the apparent density of the green parts exerts the greatest influence on the shrinkage, whereas the maximum temperature holding time has the least influence on both the shrinkage and surface roughness. In contrast, the layer height has the greatest influence on the surface roughness. Research limitations/implications Future research can be focused on using the proposed model to investigate the effect of processing and technical parameters on the MME parts’ dimensional shrinkage and surface roughness. Practical implications This study shows theoretical basis and technical insight into improving the forming accuracy and quality of the MME parts. Originality/value Novel reliable theoretical models to provide theoretical basis and principle to reveal the physical phenomena and mechanism of MME parts.