Selective laser melting is a frequently used, powder bed fusion additive manufacturing technology for producing metallic parts. However, appropriate surface quality cannot be achieved, so post-processing is often necessary. Subsequent machining of surfaces serves multiple objectives such as improvement of dimensional accuracy, changing surface roughness and modification of the residual stress state for higher surface hardness. Beyond its several advantageous properties, Ti6Al4V material has, as its weaknesses, low tribological behavior and wear resistance. Sliding friction burnishing is a conventional chipless and coolant-free environmentally conscious technology for surface modification that is appropriate for simultaneously decreasing surface roughness and increasing surface hardness. Until now, there has been a research gap regarding the diamond burnishing of selective laser melted Ti6Al4V parts. In this study, we investigated how the surface roughness of selective laser melted parts can be modified via sliding friction burnishing. 2D and 3D characteristics of surface roughness were measured by a chromatic roughness measuring device. Indices of surface roughness improvement were defined and studied as a function of selective laser melting parameters. Optimal manufacturing parameters of laser power—P = 280 W and scanning speed u = 1200 mm/s—for effective surface improvement via burnishing are proposed.

Abstract. The regular cleaning up of the materials deposed in sewer networks is realised with equipment that uses pressure water jets. The functioning of this equipment is dependent on certain process parameters that can vary, causing variations of the impact forces. The research method of this study is the experiment. The purpose of this study is to determine the equation of impact forces produced by water jets in two ways: once using the Taguchi design of experiments and secondly using the full factorial design of experiments. For the experimental determination of the impact forces a stand for generating water jets and a device for measuring the impact forces are used. Finally, an analysis of the advantages and disadvantages of the two methods used is presented.

Nowadays additive manufacturing continues to gain more and more space in industrial technology. In particular, FDM (fused deposition modelling) machines have become easily available to the public. Quality of parts is impacted by several factors. In this study we investigate layer thicknesses of a prototype manufactured from PLA, and we pay special attention to the thickness of sequentially deposited layers.

Nowadays additive manufacturing is a rapidly developing field of production engineering. We investigated shape accuracy of test specimen made by additive manufacturing technology. It is demonstrated that this method has systematic error, but this error is below the barroer given by the manufacturer, and reliability of the machine is high, so that it produces dimensions of manufactured parts with very small standard deviation.

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