Mechanical properties of CF-reinforced PLA parts manufactured by fused deposition modeling

Abstract

Many parameters of fused deposition modeling (FDM) influence the resulting mechanical properties. This can become a key factor if those parts are intended for commercial applications. This study focuses on the influence of nozzle temperature and infill line orientations for parts made with short carbon fiber (CF)-reinforced polylactic acid (PLA). Tests bars made of PLA and PLA-CF composite were produced under carefully selected conditions. As expected, PLA-CF yields higher tensile properties compared to PLA, owing to the strengthening effect of high modulus CFs. Maximum tensile properties are attained for a nozzle temperature of 230°C, for both PLA and PLA-CF. This temperature was thus selected for probing the effects of infill orientations in test bars. Among the multiple orientations tested, the combination [0°, 15°, −15°] relative to the long axis of the test bar yields the highest levels of tensile properties for both PLA and PLA-CF over the “all-purpose” [45°, 135°] orientation. Annealing can also affect crystallinity and mechanical properties of manufactured parts. Through differential scanning calorimetric analyses, the degree of crystallinity was assessed for samples annealed under various conditions. Results show that annealing increases crystallinity in PLA and PLA-CF samples, with a lower cooling rate yielding higher values. The Young’s modulus exhibits the same behavior for annealed and as printed parts, with a lower cooling rate yielding higher modulus values. This is attributed to a relaxation of the material structure as well as to the orientation of polymer chains toward the CFs.

FDM-Based 3D Printing of Polymer and Associated Composite: A Review on Mechanical Properties, Defects and Treatments

“…A similar experiment was conducted by Magri et al [ 155 ] to investigate the effect of infill and the printing temperature of CF/PLA composite. With that, the optimum nozzle temperature and the print orientation to achieve higher tensile strength was obtained as 230 °C and [0°, 15°, −15°].…”

Biodegradable Poly(Lactic Acid) Nanocomposites for Fused Deposition Modeling 3D Printing

“…Uniform distribution of additives ensures that agglomerates do not clog the printing apparatus or cause weak points in the printed material [ 11 ]. Compounding the complex nature of FDM 3D printing, various printing parameters—raster angle, raster width, layer thickness, build orientation, infill density and pattern, feed rate, and air gap—also have large effects on the quality and mechanical properties of FDM-printed parts [ 12 , 13 , 14 , 15 , 16 , 17 ].…”

Experimental investigation and optimization of printing parameters of3Dprinted polyphenylene sulfide through response surface methodology

“…The use of annealing heat treatment on polymer‐based parts, such as annealing, offers a multitude of advantages, like reduction of residual stresses, improvement of dimensional stability, reduction of defects, and improvement of physical and mechanical properties. [ 39 ] Recently, El Magri et al [ 22 ] studied the influence of annealing treatment on the crystallinity and mechanical properties of 3D printed PLA and short carbon fiber‐reinforced PLA. They found that annealing treatment at a low heating/cooling rate (2°C/min) improve significantly the degree of crystallinity, with favorable results on the mechanical properties of manufactured parts.…”