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

This paper deals with vibration-based monitoring of micro-milling of DMLS Ti-6Al-4V ELI using a SCHUNK iTENDO² smart toolholder. The study evaluates the applicability of vibration signals for assessing process conditions during machining with a 1 mm diameter end mill. Annealed and non-annealed samples were machined under different cutting directions relative to the build layers and different initial surface states. The tests were carried out at constant cutting speed, feed per tooth and depth of cut, while vibration data were recorded continuously. The machined grooves were then evaluated by optical and profilometric methods with emphasis on burr formation and edge quality. The results showed that annealing had the strongest positive effect on process stability, reducing vibration levels and significantly improving edge quality. The lowest burr formation was observed in annealed samples machined perpendicular to the printed layers, whereas the non-annealed material exhibited higher dynamic loading and substantially larger burrs. The study confirms that smart toolholder-based vibration monitoring can provide useful information about changes in machining conditions during micro-milling of DMLS titanium alloy and can support further development of process diagnostics in finishing of biomedical components.

Titanium alloys are essential in biomedicine due to their high specific strength and biocompatibility, with surface properties directly influencing the successful osseointegration of implants. In this study, surface texturing of an experimental titanium alloy was performed using an ultrafast femtosecond laser with varying pulse energies. Roughness and topography were analysed using optical profilometry and confocal laser scanning microscopy, while microhardness was measured by the Vickers method. The results show that a pulse energy of 2.1 µJ, with a wavelength of 1030 nm, pulse duration of 190 fs, and repetition rate of 1 MHz, constitutes the optimal laser process parameters for achieving the desired surface properties in engineering and biomedical applications.

New types of materials have been developed for years, including titanium-based alloys, which have the potential for various applications. Due to the combination of their very good mechanical properties with outstanding corrosion resistance and excellent biocompatibility, titanium alloys are developing into materials that can be used in aerospace, automotive, energy systems and especially in medicine. A fundamental understanding of the phase transformations that occur at high temperatures in all these cases, especially during cooling from elevated temperatures, is necessary to achieve optimal mechanical properties of titanium alloys. It is known that the mechanical properties of titanium alloys depend on a significant extent upon the microstructure. Therefore, it is very important to understand the nature of the phase transformations that occur under different heat treatment conditions the leads to microstructure development of titanium alloys microstructure. The aim of this article is to review the current state of knowledge and previous research and to point out some of the most interesting phase transformations of titanium alloys.

Direct Metal Laser Sintering (DMLS) is a revolutionary technology that allows a production of fully functional metal parts directly from a 3D CAD data, eliminating the investment to production tools and technologies which brings considerable cost and time savings. Metal parts made by DMLS technology are fully comparable with casted or machined parts. A range of application of DMLS technologies is very wide – from prototypes, through short-run production to final products. Advantages of DMLS technology are arising along with complexity of parts – more complex geometry of parts (in terms of shape and occurrence of the detail) make DMLS technology even more
economically effective.

This study aims to present the practical application of the Dentistry 4.0 concept based on obtaining data on the patient’s intraoral situation and bone base using CBCT, processing them into a digital model, creating a digital twin, and then developing an intraprocedural navigation procedure through a dedicated surgical guide and then designing and manufacturing, using 3D printing, implantprosthetic restorations. The study describes the results of the author’s work, indicating the engineering aspects of implant prosthetic treatment based on the description of cases related to the reconstruction of single missing teeth using dental implants implanted in the case of difficult anatomical conditions of the bone base and/or adjacent teeth, with a discussion of the material selection methodology, technological and structural design, using additive manufacturing.
The technology for the design, manufacture and application of implant-prosthetic restorations developed by the author, preceded by a fully navigated implantation procedure of dental screw implants, illustrates in practice the full application of the Dentistry 4.0 concept, where the latest technologies, including primarily computer-aided design and computer-aided CAD/CAM manufacturing, the use of a digital twin, supporting surgical procedures through the use of templates navigating the operator’s actions and additive manufacturing allow for a radical increase in the availability of implant-prosthetic solutions for patients with difficult anatomical conditions, both due to a limited bone base and anomalies of the anatomy of adjacent teeth. Thanks to the latest technology, not only is it possible to perform this type of procedure, but it is also possible to perform the procedure in a short time, with minimal interference in the patient’s tissues and ensuring the optimal shape of the prosthetic restoration itself.

Titanium alloys due to their good properties are increasingly used in biomedicine. However, in order to improve certain properties, titanium-based alloys with new chemical compositions are designed. In order to be characterized in a satisfactory manner, they must first be adequately prepared. In this paper the two most influential parameters were varied: grinding time and force, while the speed of rotation of the grinding wheel was constant. After grinding with the highest gradation of grind paper, the samples were observed under a light microscope to determine the condition of the surface. Then their hardness was determined by the Vickers method with different indenter loads. After that, the samples were polished under the same conditions, and their hardness was determined again. The obtained hardness values were numerically analyzed and the corresponding functional dependences of the measured hardness on the grinding parameters (time and force) and on the indentation force were determined.

The article is focused on the research of the influence of different blasting means on the surface of the titanium alloy Ti6Al4V, which was made by the sintering technology of layered metal powders (DMLS) in terms of microgeometry. The resulting microgeometry values of the titanium alloy placed on the platform in different sectors. Individual sectors had different laser power settings. The blasting was carried out at a constant pressure of 6 bar. Samples were then subjected to roughness measurement by contact method in accordance with STN EN ISO 4287. Individual parameters were subsequently statistically evaluated. A 3D topography of roughness of individual blasted materials was made.

The effect of the low-frequency vibration processing on the residual elastic stresses in the Ti-6Al-4V alloy manufactured by 3D printing (Selective laser melting) was investigated. The studied sample was manufactured horizontally in respect to the building platform. Different vibration oscillations modes (vertical, horizontal, and elliptical) were chosen for study. The oscillations were done with frequency of 16 Hz, and a processing time was 20 minutes. Studies shown that 3D printed sample had a high level of residual elastic stresses, which were changed after vibration treatment. The optimal parameters of vibration processing, which provide a minimum level of residual elastic stresses in 3D printed Ti-6Al-4V alloy are discussed.

The application of the selective laser melting (SLM) method requires knowledge of not only the properties of the material after manufacturing, but also after mechanical loading. The aim of this work is to investigate the strain-rate dependence and microstructure of Ti6Al4V samples manufactured by SLM method with different angles to the building platform. SLM Ti-6Al-4V samples were manufactured using the EOSINT M280 (EOS GmbH) at angles of 0°, 30°, 45°, 90° to the building platform. A medicine Ti6Al4V (ASTM grade 23) powder was used for the study. Tensile tests were performed with an Instron test machine using two strain rates 0.5 mm/min and 2 mm/min at room temperature. It was found the strain-rate dependence in the studied samples. The features of the mechanisms of hardening and softening in an investigated SLM Ti-6Al-V alloy are discussed.

Direct Metal Laser Sintering (DMLS) is a revolutionary technology that allows a production of fully functional metal parts directly from a 3D CAD data, eliminating the investment to production tools and technologies which brings considerable cost and time savings. Metal parts made by DMLS technology are fully comparable with casted or machined parts. A range of application of DMLS technologies is very wide – from prototypes, through short-run production to final products. Advantages of DMLS technology are arising along with complexity of parts – more complex geometry of parts (in terms of shape and occurrence of the detail) make DMLS technology even more economically effective.

Since diffusion bonded joint is formed from atomic migration across an interface without a liquid phase, the interface is homogeneous microstructure and hence mechanical properties are not different from those of the matrix metal. However, it is not easy to control process variables at high temperature. This paper presents diffusion bonding process and a machinery with tool material selection to develop diffusion bonding press machine for joining complex contoured metals using hot forming and diffusion bonding technology.

TiAl6V (ELI) has the low density, low elastic modulus and high strength. Biocompatibility of this material allows one to adapt it to human implant production and successfully use in the manufacture of surgical implants. Spherical argon-atomized Ti6Al4V (ELI) (45µm) powder from TLS Technik was used for study. The chemical composition complies with the ASTM F-136 (grade 5), ASTM B348 (grade 23) standard for surgical implant applications. Two machines from two scientific centers (Russia and South Africa) were used for the manufacturing of the alloys. Analysis of the oxygen and nitrogen contamination in SLM alloys was done with Van de Graaff accelerator with 2 Mega Volts. It is found that the oxygen concentration in both samples is about 0.2 wt. % and decreases with the increasing of the sample depth; the nitrogen concentration is about 0,02 wt%. X-Ray results show an absence of beta (BCC) phase in both samples. TEM studies found the metastable martensitic structure and silicon nitride Si3N4.