Mastering binder jet 3D printing of 316L stainless steel: A descriptive model approach to particle size and deposition thickness

Abstract To fill the gap in a rational strategy for materials selection and process optimization, the effect of 3D binder jetting on the packing density and pore structure of AISI 316L SS powders with a wide range of particle sizes ( d = 5–60 µm) and deposition thicknesses $$\left( {1 \le H/d \le 10} \right)$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mfenced> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>≤</mml:mo> <mml:mi>H</mml:mi> <mml:mo>/</mml:mo> <mml:mi>d</mml:mi> <mml:mo>≤</mml:mo> <mml:mn>10</mml:mn> </mml:mrow> </mml:mfenced> </mml:math> were investigated. We introduce a new dimensionless parameter, $$\varphi = \frac{{1 - \left( {d/H} \right)^{2} }}{{1 + \left( {d/H} \right)}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>φ</mml:mi> <mml:mo>=</mml:mo> <mml:mfrac> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>-</mml:mo> <mml:msup> <mml:mfenced> <mml:mrow> <mml:mi>d</mml:mi> <mml:mo>/</mml:mo> <mml:mi>H</mml:mi> </mml:mrow> </mml:mfenced> <mml:mn>2</mml:mn> </mml:msup> </mml:mrow> <mml:mrow> <mml:mn>1</mml:mn> <mml:mo>+</mml:mo> <mml:mfenced> <mml:mrow> <mml:mi>d</mml:mi> <mml:mo>/</mml:mo> <mml:mi>H</mml:mi> </mml:mrow> </mml:mfenced> </mml:mrow> </mml:mfrac> </mml:mrow> </mml:math> , and demonstrate that the packing density and binder-induced pores abruptly varies with $$\varphi$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>φ</mml:mi> </mml:math> in a semi-log scale and d −2 , respectively. In light of the mechanistic understanding of the transient behavior, the optimum d/H value to attain dense and homogeneous parts is proposed. Graphical abstract