Experimental realisation of build orientation effects on the mechanical properties of truly as-built Ti-6Al-4V SLM parts

This paper proposes an integrated approach to determine optimal build orientation for powder bed fusion by laser (PBF-L), by simultaneously optimizing mechanical properties, surface roughness, the amount of support structure (SUPP), and build time and cost. Experimental data analysis has been used to establish the objective functions for different mechanical properties and surface roughness. Geometry analysis of the part has been used to estimate the needed SUPP and thus evaluate the build time and cost. Normalized weights are assigned to different objectives depending on their relative importance allowing solving the multi-objective optimization problem using a genetic optimization algorithm. A study case is presented to demonstrate the capabilities of the developed system. The major achievements of this work are the consideration of multiple objectives and the establishment of objective function considering different load direction and heat treatments. A user-friendly graphical user interface was developed allowing to control different optimization process factors and providing different visualization and evaluation tools.

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Anisotropic Mechanical Properties of Rapid Prototyping Parts Fabricated by Stereolithography

Science of Advanced Materials ◽

10.1166/sam.2021.4071 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1812-1819

Author(s):

Na-Na Yang ◽

Hao-Rui Liu ◽

Ning Mi ◽

Qi Zhou ◽

Li-Qun He ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Elastic Modulus ◽

Brittle Fracture ◽

Fracture Surface ◽

Elongation At Break ◽

Build Orientation ◽

Range Distribution ◽

Anisotropic Mechanical Properties ◽

Orientation Experiment

Stereolithography (SLA)-manufactured parts behave with anisotropic properties due to the varying interface orientations generated by the layer-based manufacturing process. Part build orientation is a very important factor of anisotropic mechanical properties. In this paper, the build orientation experiment was designed to study the anisotropic behaviour of the mechanical properties of the SLA parts based on the orientation relationship between the force and the layer. The results show that there are obvious brittle characteristics on the fracture surface of the specimens and microcracks perpendicular to the direction of the layer distributed on the side of the fracture. The mechanical properties under brittle fracture have different degrees of sensitivity to the build orientation. Among all the build orientations, whether a specimen is built flat or on an edge shows obvious difference in tensile strength, and the relative range distribution reaches 35%. The changes in elastic modulus and the elongation at break are the most obvious in different angles relative to the XY plane, and the relative range distribution reaches 62% and 56% respectively. In all the build orientations designed, the tensile strength is the largest when it is placed on the edge at 0° with Y-axis in the XY plane, the elastic modulus is the largest when it was placed vertically, and the elongation at break is the largest when it is placed flat at 45° with Y-axis in the XY plane.

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