PLA are the most sustainable alternatives and can fit in a wide-range of applications of electronics, nonwoven fabrics and food packaging. With these PLA’s adaptability and suitability in many techniques of production such as injection moulding, extrusion, and blow moulding, PLA has become high interest in the production process. Besides, PLA as a thermoplastic polyester that mostly obtained from renewable materials [1]. Infill patterns can affect the mechanical properties of 3D printed PLA and cPLA. PLA with zig zag infill pattern has higher tensile strength of 23.409 MPa compared to PLA with grid and concentric infill pattern. Meanwhile, cPLA with grid infill pattern has higher tensile strength of 30.5638 MPa compared to cPLA with concentric and zig zag infill pattern. By using the suitable infill pattern parameter, the 3D printed PLA and cPLA can have good mechanical properties and can be applied in packaging, pharmaceuticals, textiles, automotive, biomedical and tissue engineering. It has been widely investigated for biomedical applications due to its biodegradability and biocompatibility.

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Polylactic acid (PLA) is derived from natural aliphatic polyester resources for instance sugarcane or starch based plants. PLA also known as a biocompatible and biodegradable thermoplastic and found widely in multiple applications like electronic and electrical devices, biomedical, food packaging and the engineering field. PLA have attracted attention in production potential due to its superior attributes like ease of processing, high strength and high modulus. Infill density, raster angle and infill pattern can influence the mechanical characteristics of materials like PLA, acrylonitrile-butadiene-styrene (ABS), polyetheretherketone (PEEK). In this paper, the relationship between infill density and raster angle was studied to investigate the mechanical performances of PLA by using 3D printers. 3D printing is used to fabricate more complex 3D design objects. The tensile test was involved to evaluate the properties of pure PLA. For pure PLA, 0° raster angles with 100% infill density show the highest tensile strength and Young’s modulus which are 28.926MPa and 1262.7MPa respectively. However, a decreasing trend of break elongation reveals in PLA as infill density increases for both 0° and 90° raster angle. Optimization of printing parameters become crucial to provide high quality materials for 3D printing in order for education, packaging, engineering and biomedical applications.

This work aimed to study the effect of zinc oxide (ZnO) filler suspension on the mechanical, electrical, and thermal properties of polylactic acid (PLA)/ZnO and cPLA/ZnO. Fused deposition modelling, one of the additive manufacturing methods, was used to fabricate the PLA specimen. PLA was used as the main material in this project, and the ZnO suspension was added during the printing process. The speed of the dispenser (low speed = 1,000 rpm, medium speed = 1,400 rpm, and high speed = 1,800 rpm) was the parameter that was varied to control the filler content of the composite. All the samples underwent a tensile test to determine the mechanical properties, followed by the scanning electron microscopy (SEM) test to analyse the fracture surface properties of the tensile test. SEM observations showed the PLA samples’ inherent smooth appearance, but the PLA/ZnO composite showed a rougher surface. PLA and cPLA composites showed an enhanced storage modulus but lower loss modulus than the pure samples. Because of the high thermal and electrical conductivity of carbon black and ZnO, cPLA composites had higher electrical and thermal conductivity than PLA composites.

3D printed polylactic acid (PLA) composites reinforced with zinc oxide (ZnO) were successfully fabricated by attaching a ZnO dispenser beside a MendelMax RepRap Printer. Mechanical and electrical testings were performed to characterize the properties of PLA/ZnO and cPLA/ZnO composites. PLA polymer filament is a biodegradable material with the same strength and modulus as other plastic materials. This work emphasizes the effects of printing parameters (infill density and raster angle) on the mechanical properties and electrical conductivity of PLA/ZnO composites. The combination of 100% infill density and 0° raster angle resulted in a substantial increase in the tensile strength and Young’s modulus, but reduction in break elongation. As the infill density increased and shifted from 90° to 0° raster angle, the storage modulus was enhanced but the damping factor declined. Scanning electron microscope images proved ZnO was dispersed in the PLA matrix. Optical measurements showed a large air gap across the 35% compared to the 100% infill density. Conductive PLA composites (cPLA/ZnO) enhanced electrical conductivity when increasing infill density compared to PLA composites. Therefore, optimizing printing parameters could help manufacturers provide superior quality structure and cPLA composites for electrical and electronic applications due to good electrical conductivity.