Existence of standardized materials and product standards for various products gives confidence in complete material selection process. In case of welded steel products, respective product standards clearly define requirements for design and fabrication. Among many properties, four are mostly considered: strength, ductility, toughness, and weldability. Nowadays products are more demanding than ever, and it is not possible to consider single property anymore, but two or even three of them. In such cases, selection charts are used, making material selection easier. This paper provides selection charts and corresponding design criteria defined in welded product standards for selected structural steel grades. Values presented in selection charts are acquired through own researches, as well as from available literature. Considered structural steels are grades with yield strength from 355 to 960 MPa, available in three mayor delivery conditions: normalized, thermo-mechanically treated, and quenched and tempered.

While fused deposition modeling (FDM) is one of the most used additive manufacturing (AM)process today due to its ability to produce products with very complex geometries and with wide range of different thermoplastic materials. Engineers have the option of making parts with the most commonly used thermoplastics, such as ABS, PLA, PET-G, a variety of blends, as well as engineered thermoplastics for aerospace, medical, automotive, electronic and other specialty applications. The aim of this paper is to investigate tensile properties of carbon reinforced PLA and carbon reinforced PET-G materials, and make a comparison of carbon PLA with PLA and carbon PET-G with PET-G material. For every material it will be tested 2 specimens with different 3D printing orientation angle (0, 15, 30 and 45) prepared according to ISO 527-2. Specimens would be 3D printed on Ultimaker 2+ with steel nozzle and under the same conditions of 3D printing, in order to reduce impact of unwanted factors on material tensile properties. The results of this paper will be useful to see whether it is profitable to use carbon-reinforced materials and whether they really increase the tensile properties of basic materials.

Today, one of the most used material in FDM (fused deposition modelling) 3D printing technology is PLA (polylactic acid). On market today, there are many different companies that producing PLA material filament for 3D printers with different diameter and colours. Previous research showing that there are so many parameters in FDM technology that affect on mechanical properties of 3D printed material like layer height, infill density, temperature etc. Topic of this article is to investigate whether colour of PLA material effect on material tensile properties and in what amount. It will be tested more than 10 different colours of PLA material, and for every colour it will be tested 3 specimens. Specimens are prepared according to ISO 527-2, and all printed with same 3D printing parameters and with 100% infill. Also, all used materials are of same company and for every colour specimen will be 3D printed from same filament spool. All this is done to avoid other parameters to effect on material properties. The results of this study will be useful for colour selection of the PLA material without compromising the material tensile properties of 3D printed product.

Fused deposition modeling (FDM) is a rapidly growing additive manufacturing technology for various applications in field of engineering. Mechanical properties of 3D printed materials in FDM technology depend on various parameters. Literature suggests that type and density of infill are parameters that affecting the mechanical properties of 3D printed materials, and also have direct influence on 3D printing time and amount of 3D printed material. In this paper influence of infill type and density on tensile properties, 3D printing time and amount of 3D printed material will be investigated and presented. Total of 13 different types of infill and for every type it will be tested 9 specimens with different infill density from 10% to 90%. Every specimen would be 3D printed of PLA material with same colour and 3D printing parameters, also at the same position on printer bed to maximally reduce influence of other factors on mechanical properties of material. The obtained results would give us a wider picture of how to maximally save on 3D printing time and amount of material consumed in the production, but to still keep required tensile properties.