Effect of Process Parameters on the Tensile Strength of Fused Deposition Modelling Parts

Abstract

Fused deposition modelling, the most common form of three-dimensionalprinting, builds a part by depositing molten plastic layer upon layer, andbecause the part is built up rather than cut from a solid block, its strengthdepends not only on the material but on how it is printed; the processparameters chosen, such as the thickness of the layers and how densely theinterior is filled, strongly affect how strong the finished part is. This studyexamines the effect of process parameters on the tensile strength of fuseddeposition modelling parts, focusing on the layer thickness and the infilldensity. Test specimens were printed with different layer thicknesses anddifferent infill densities, and their tensile strength, the force per unit area they could withstand before breaking when pulled, was measured and compared. The infill density had a strong effect: parts printed with a denser interior were considerably stronger, because more material carried the load, a fully filled part being substantially stronger than a half-filled one. The layer thickness also mattered: parts built from thinner layers were stronger than those built from thicker layers at the same infill, because thinner layers bond over a greater number of interfaces and give a more uniform structure. The strongest parts were therefore those printed with a high infill density and thin layers, though these also took longer to print and used more material, while the weakest were the thickly layered, sparsely filled parts that printed fastest. The study shows that the tensile strength of fused deposition modelling parts is governed substantially by the infill density and layer thickness, and it discusses the trade-off between strength and the time and material that printing consumes. KEYWORDS: Additive manufacturing, Fused deposition modelling, 3Dprinting, Tensile strength, Process parameters, Infill density, Layer thickness, Mechanical properties, Manufacturing