3D printing as a manufacturing method is gaining more popularity since 3D printing machines are becoming easily accessible. Especially in a prototyping process of a machine, they can be used, and complex parts with high quality surface finish can be manufactured in a timely manner. However, there is a need to study the effects of different manufacturing parameters on the materials properties of the finished parts. Specifically, this chapter explains the effects of six different process parameters on the impact resistance. In particular, print temperature, print speed, infill ratio, infill pattern, layer height, and print orientation parameters were studied, and their effects on impact resistance were measured experimentally. Moreover, the optimum values of the process parameters for impact resistance were found. This chapter provides an important guideline for 3D manufacturing in terms of impact resistance of the printed parts. Furthermore, by using this methodology the effects of different 3D printing process parameters on the other material, properties can be determined.
TopIntroduction
Additive manufacturing (AM), also known as 3D printing, is receiving great attention due to the fact that it allows easy and time efficient realization of designs from prototypes to functional products with complex geometries (Zotti et al., 2018), (León-Cabezas et al., 2017), (Castro et al., 2015). The process of AM starts with computer aided design and continues with printing successive layers on top of each other to obtain the desired final shape. 3D printing technology started to be used in mid-80’s with a process known as Stereolithograpgy and was followed by powder bed fusion, fused deposition modelling, inkjet printing and contour crafting, chronologically (Spoerk et al., 2018). The main printed parts using Stereolithograpgy 3D printing technology are patterns, mold and models by photopolymerization. Powder bed fusion (or selective laser melting) allows the manufacturing of 3D parts by selectively melting and layer by layer fusing metallic powder materials (Arisoy et al., 2019). For the process of fused deposition modelling, 3D computer models can be printed without requiring a mold (Daver et al., 2018). In contour crafting, the parts are printed by integrating material delivery and installation in to one system (Zareiyan & Khoshnevis, 2017). With the aid of this rapidly developed technology, different material groups from polymers to metals with very complex geometries are now able to be printed. However, in order to use these 3-D printed materials in design, the mechanical characterization of them is of utmost importance.
The mechanical characterization of 3-D printed parts has been carried out by using several experimental methods. In order to determine the material properties, tensile tests, compression tests and indentation tests have been conducted at different loading conditions (Spoerk et al., 2018; Ahn et al., 2002; Rankouhi et al., 2016). Particularly in these studies, strength, ductility, modulus and hardness values of 3-D printed materials have been measured. In addition, as a conclusion of these studies, it has been proven that the mechanical properties of 3-D printed materials depend on both the unprinted material and 3-D process parameters. For instance, optimum tensile properties are obtained when the filaments are parallel to the loading direction (Dizon et al., 2018). However, in spite of many works on the mechanical properties of 3-D printed materials under tensile and compressive loads, the number of works on the impact response of 3-D printed materials are very limited. In these limited studies, effects of building orientation, layer thickness, fiber volume content, lattice topology and build direction on the impact performance of 3-D printed materials have been investigated (Caminero et al., 2018; Bourell et al., 2017; Ngo et al., 2018; Lou et al., 2018). However, there is a lack of research about how 3-D printed materials are subject to impact loadings during operation. Therefore, the impact response of these materials should also be investigated in order to utilize them in safe design.