Shrinkage behaviour of material extrusion steel 316L: influence of primary 3D printing parameters

Abstract

Purpose The wide application of metal material extrusion (MEX) has been hampered by the practicalities associated with the resulting shrinkage of the final parts when commercial three-dimensional (3D) printing equipment is used. The shrinkage behaviour of MEX metal parts is a very important aspect of the MEX metal production process, as the parts must be accurately oversized to compensate for shrinkage. This paper aims to investigate the influence of primary 3D printing parameters, namely, print speed, layer height and print angle, on the shrinkage behaviour of MEX Steel 316L parts. Design/methodology/approach Two groups of dog-bone and rectangular-shape specimens were produced with the BASF Ultrafuse Steel 316L metal filament. The length, width and thickness of the specimens were measured pre- and post-debinding and sintering to calculate the percentile shrinkage rates. Analysis of variance (ANOVA) was used to evaluate and rank the significance of each manufacturing parameter on shrinkage. Typical main print quality issues experienced in this analysis are also reported. Findings The shrinkage rates of the tested specimens ranged from 15.5 to 20.4% along the length and width axis and 18.5% to 23.1% along the thickness axis of the specimens. Layer height and raster angle were the most statistically significant parameters influencing shrinkage, while print speed had very little influence. Three types of defects were observed, including surface roughness, surface deformation (warping and distortion) and balling defects. Originality/value This paper bridges an existing gap in MEX Steel 316L literature, with a focus on the relationship between MEX manufacturing parameters and subsequent shrinkage behaviour. This study provides an in-depth analysis of the relationship between manufacturing parameters – layer height, raster angle and print speed and subsequent shrinkage behaviour, thereby providing further information on the relationship between the former and the latter.

A Comparative Investigation of the Reliability of Biodegradable Components Produced through Additive Manufacturing Technology

“…Interestingly, the ultimate strength of the cracked sample at a 45-degree raster orientation was higher (55.65 MPa) compared to the intact sample (48.82 MPa). This suggests that the crack, in this case, might have altered the material failure mechanism, leading to a higher ultimate strength [ 44 ]. However, it is important to note that cracks generally make materials more brittle, meaning they are less likely to deform before failure.…”

Indirect Induction Sintering of Metal Parts Produced through Material Extrusion Additive Manufacturing

“…The results fit within the filament supplier guidelines that caution for an overall shrinkage of ~15%. Shrinkage upon sintering is a well-known effect of powder-based metallic additive manufacturing and has been extensively reported in relation to stainless steel 316L produced through FFF [ 71 , 72 , 73 ]. The effect is attributed to the bulk transport mechanism appearing during the final stages of sintering, whereby neck growth and the elimination of pores are dominated by the atomic particles that migrate from the bulk of the neighboring granules at the contact points [ 74 ].…”

Dimensional Accuracy and Mechanical Characterization of Inconel 625 Components in Atomic Diffusion Additive Manufacturing

“…The shrinkage thus depends on the binding agent fraction and the voids in the green part after the extrusion process. Hence, by knowing the characteristic porosity and binding agent content, the shrinkage in the different directions can be calculated [39,40]. By using the finite element method, this can also be expanded to the analysis of hotspots for potential sinter failure [29].…”