Additive manufacturing (AM) technology refers to the process of producing 3D objects by adding material in successive layers. Fused deposition modeling (FDM) is one of the AM technologies where objects are built by adding layers of melted thermoplastic filament onto the printing surface. Mechanical properties of FDM printed part depend on many influencing factors such as material composition, extruding temperature, printing parameters and environment temperature. The aim of this study was to investigate consistency of mechanical properties of elements produced by FDM additive manufacturing technology. To do so, mechanical tensile and compression tests were conducted on ten samples using polylactic acid (PLA) and ten samples using acrylonitrile butadiene styrene (ABS) thermoplastic material. Tensile tests were conducted using Shimadzu Compact Tabletop Testing Machine EZ-LX and the compression tests were done using VEB ZDM 5/91 testing machine. The ultimate tensile strength, strain, Young modulus and compression yield strength values were analyzed. The ABS thermoplastic material showed greater consistency in mechanical properties during tensile tests. Tensile strength values for PLA material varied between samples thus showing greater inconsistency in repeatability of mechanical properties. Compression tests, on the other hand, showed that PLA samples had greater consistency in mechanical properties compared to ABS samples.

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Abstract. Universal gear reducers are quite simple products, so today there are many manufacturers around the world that produce this kind of reducers. Their connecting dimensions and shape are not defined by the standard, so there is a large number of solutions. The most of manufacturers produce gear reducers with connecting dimensions and axis height, usually the same like the biggest manufacturers do (mainly company SEW), because they want to provide interchangeability of their gear reducers. It is interesting to note that most manufacturers are trying to adopt such a form of reducer that will be different from competing solutions in order to avoid an accusation of coping with someone else's solution, although manufacturers have almost identical shape and competing (copied) solutions. The paper presents, due to the volume of matter, only the analisys of forms of the housing of modern single-stage universal gear reducers in order to point out the expected directions of their further development.

Abstract:The purpose of this paper is to point out the usual methods of determining the service factor, which is the most influential parameter. In order to provide the proper selection of the size of the worm gear reducer, manufacturers are trying to take detailed look at all the factors which influence the work gear and to provide customers with the best possible solution. The greatest impact on their defining has a safety factor which is used to calculate the gear unit and the effect of an ambient temperature i.e. cooling method.

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