PSI - Issue 19

Aissa Ouballouch et al. / Procedia Structural Integrity 19 (2019) 433–441 Aissa Ouballouch et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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1. Introduction Additive manufacturing (AM) refers to a collective advance manufacturing technologies. It is a process of joining materials to make objects from a 3D model data, usually layer by layer ( ASTM F2792 - 12 Standard Terminology for Additive Manufacturing Technologies, no date)., which is invented by (‘Apparatus for production of three dimensional objects by stereolithograph y’, 1984) Charles Hull et al. in 80s. Various methods for polymer fabrication have been developed and drive from rapid prototyping to rapid manufacturing. Among these AM technologies streolithography (SLA), selective laser sintering (SLS) and fused deposition modeling (FDM) that uses polymer filaments (Dudek, 2013). The latter is the most widespread utilized system for plastics AM manufacture because of its relative low cost, low material waste and ease of use (Chua, Leong and Lim, 2003). The FDM process enables to utilize different polymer filaments such as neat feedstock, materials reinforced by chopped or continuous fibers. FDM machines work by controlled extrusion of polymer filaments. In detail, filaments melt into a semi-liquid state at nozzle and are extruded layer by layer onto a build stage where layers are fused together and solidify forming final parts. Basically, the quality of printed parts depends on post processing and varying of printing parameters like layer thickness, extrusion temperature, print speed etc. The influences of these processing parameters have been discussed by many authors in the literature. Although, few studies discuss the overall influence of the processing parameters such dimensional accuracy, mechanical properties and total cost. A study focused on the effect of printing conditions on the mechanical properties and dimensional accuracy was carried out by (Alafaghani et al. , 2017) Ala aldin Alafghani et al. This work showed that the dimensional accuracy of PLA parts is affected by building direction, extrusion temperature and layer thickness more than infill percent, infill pattern and printing speed. And the mechanical properties are influenced significantly by building direction, extrusion temperature and layer thickness and less affected by infill patterns for high infill percents and printing speed. Some fluctuation was observed. The aim of this paper is to improve the knowledge about the overall effect of printing parameters in terms of tensile and fatigue properties, dimensional accuracy and total cost. Our study focuses on the reinforced PA parts. Chopped glass fibers and short Kevlar fibers were used in printing of polymer composites. The following sections present the experimental details and results discussion. 2. Experimental 2.1. Materials Reinforced Nylon (polyamide) filaments were supplied by CoreXtrusion Group ( COREXTRUSION – Spécialiste de l’extrusion de filaments 3D sur mesure , 2019) . They are glass reinforced polyamide (GRPA) with 15% of short glass fiber and Kevlar reinforced polyamide (KRPA) with the same percent (15%) of chopped kevlar fiber. They are provided in the market by their commercial name TECHStrongTM and TECHArmedTM respectively. These both filaments have a diameter of 1.75mm. Their data sheet and detailed information are accessible and can be consulted via ( COREXTRUSION – Spécialiste de l’extrusion de filaments 3D sur mesure , 2019) 2.2. The 3D Volumic 3D printer Figure 1 shows a photopraph of the 3D Volumic 3D printer ( Imprimante 3D Professionnelle | VOLUMIC 3D , no date), more specifically Stream 30 Pro type from which test specimens were manufactured additively. The printing process is based on using one print head as the feedstock is formed by reinforced filaments containing chopped fibers. The design of the FDM 3D machine presents some interesting advantages: end of material detection, semi auto calibration, protection to overheating and enabling the printing with most of plastic filaments PLA, ABS, PA including reinforced ones … Its overall dimensions are 520x585x465mm.