Effect of Process Parameters and Thermal Annealing on Mechanical Properties of Fused Filament Fabricated Specimens

Abstract

Fused filament fabrication (FFF) is the most popular additive manufacturing technique to produce three-dimensional complex structures. It is a layer by layer additive manufacturing technique in which parts are created by the addition of one layer over another by using melted thermoplastic polymers. Fused filament fabricated parts have broad applications in automotive, medical, art and adornments fields, etc. The mechanical and thermal properties of FFF printed parts mainly depends on process parameters like infill pattern, layer thickness, infill speed, Nozzle temperature, infill density. The only way to improve the mechanical and surface properties of a part after printing is to make use of the post-processing techniques. Thermal annealing is one of the best post-process treatment for fused filament fabricated parts to improve mechanical properties. The objective of this paper is to provide an overview of the effect of different process parameters on the mechanical properties of fused filament fabricated parts and also investigate the influence of thermal annealing on the mechanical properties of printed parts. Mechanical properties of printed parts are analyzed by conducting different mechanical tests like tensile strength, compressive strength, and impact strength tests, etc. These mechanical tests are conducted on the standard specimens of ASTM or ISO standards. Thermal annealing should be possible by heating the printed part in a temperature range between the glass change temperature (Tg) and the melting point temperature (Tm) of the material used. It is found that the mechanical properties like tensile strength, compressive strength, and impact strength, etc. depend more on the process parameters like infill density, layer thickness, nozzle temperature, etc. It is observed that thermal annealing caused an improvement in flexural strength and tensile strength of fused filament fabricated parts. The tensile test for high tensile PLA showed that the maximum tensile strength furthermore, modulus for the non-heat-treated examples was acquired 65.75 MPa and 4.9 GPa individually, at 250°C. The tensile test results for heat-treated examples exhibited that the maximum tensile strength and modulus were gained 67.4 MPa and 5.65 GPa, separately, at 250°C.