International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Additional manufacturing (AM), commonly known as 3D printing, exists for 40 years, still evolving and improving. AM has gained great popularity in modern industries due to many advantages concerning conventional manufacturing technologies. Consequently, AM is one of nine pillars of the currently dominating industry trend – Industry 4.0. Initially, AM was mostly used for making models. Now, objects made by AM technologies, often are physical parts ready to be used as final products or to be installed as parts of assemblies in more complex systems. Because of that, in more applications, the mechanical properties of these parts have to be known for the purpose to determine load carrying capacity essential for their functionality. Mechanical properties are being tested using appropriate methods, specimens, and equipment. In order to obtain comparable and evaluable test results, the test procedures and means should be s tandardized. Therefore, there was a need to develop standards for testing materials used for AM. International standardization in the field of AM started 10 years ago. The international body for standardization ISO developed and published a certain number of standards, but this is just beginning. This paper discusses aspects of AM standardization in the field of testing the mechanical properties of materials for 3D printing using fused deposition modelling (FDM). As an illustration of the standard application, specimens were prepared for testing the tensile properties of plastic materials widely used in AM: PLA, PETG and ABS+.

Three-dimensional (3D) printing technologies have been developed for prototype purposes. However, it has become possible to manufacture various functional parts with improving mechanical properties of 3D printing materials. Although polylactic acid (PLA) is the most widely used 3D printing material, the mechanical properties required for functional parts are not sufficient. For this reason, carbon fibre reinforced PLA composites are preferred as 3D printing material to advance the mechanical properties of the fabricated parts. However, for 3D printed parts, it is known that the layer thickness and printing orientation angles affect the mechanical properties. In this study, unreinforced PLA and 15% carbon fibre reinforced PLA composite tensile specimens were 3D printed using fused deposition modeling (FDM) technique. The effects of printing orientation angle and layer thickness on modulus of elasticity and tensile strength are investigated. 3D printed unreinforced PLA samples exhibited better tensile performance as compared to carbon fibre reinforced PLA composite samples.

Three-dimensional (3D) printing technologies are the most promising method in the production of functional parts. Although 3D printing technology includes various methods, fused deposition modelling (FDM) is the most widely used one. In FDM, generally polylactic acid (PLA) filaments are used to fabricate 3D geometry by stacking individual layers. In fact, FDM is a complicated process with numerous parameters that affect printing quality. Printing parameters such as printing orientation, layer thickness, printing orientation angle, filling ratio, filament feed rate, etc. have significant impact on the quality and performance of FDM printed parts. Since the mechanical properties are very important for functional parts, the effect of these parameters on the mechanical properties of the PLA specimens has been extensively studied. However, there is no sufficient data in the surface characterization literature of these parameters. In this study, the effect of layer thickness and printing temperature on the surface properties of PLA specimens printed using FDM was investigated.