Volume 30 (2022): Edizione 50 (June 2022)

The paper briefly describes factors influencing the effectivity of forgings production. It focuses on lifetime of forging dies and possibilities of surface layers mechanical strengthening application. Included are also the results of experiments in the area of surface layer strengthening of forging die tool steels by shot peening. The article presents the results obtained on the basis of monitoring the influence of the initial hardness on the surface roughness after shot peening and on the course of hardness in the surface layer after shot peening. The results of the experiments confirmed the beneficial effect of mechanical reinforcement (strengthening) on the final properties of surface layer.

The article focuses on the influence of infill (internal structure of components) in the dimensional accuracy of dental master models during the processes of their fabrication by Fused Deposition Modeling (FDM) technology, and their vacuuming process for production of clear orthodontic aligners. The components, in this case, were the upper jaws (maxillary teeth) of two individual patients (Tzina, Dimitris), which were obtained by intraoral 3D scanning. Patient Tzina at the time of intra-oral scanning was 27 years old and Dimitris was 23 years old. The method of 3D printing was the FDM, and the material used in this research was thermoplastic high impact polystyrene (HIPS). Three different percentages of infill density were set, 60%, 80%, and 100%. For each setting, there were five specimens (thirty 3D printed dental models in total, 15 for Tzina and 15 for Dimitris). After the 3D printing, the models were digitized and measured by GOM ATOS II Triple Scan MV 170 optical 3D scanner and compared with the values of the initial digital models. Then the dental master models underwent the process of Essix-aligners formation (single press) and were rescanned and measured again. The outcome of this research was to examine if the dental master models remain dimensionally accurate after these processes, and which infill provides the optimal and medically approved accuracy.

Internal turning process is a very important and widely used process for enlarging and finishing holes. Especially for the components that work with external members, this operation needs to assure surface and geometric quality. In that case, the correct definition of working parameters will directly contribute to the quality of component. Aim of the current research was to analyse the form error and the roughness of workpieces submitted to internal turning process using boring bars in long overhangs with three different internal tools (steel, carbide and antivibrating tool). For the experiments, heat-treated DIN EN 1.2842 (ISO 90MnCrV8) steel with 58 HRC of hardness was submitted to boring process using CBN (cubic boron nitride) inserts, and a boring bar with the most possible rigid clamping system (Easy Fix). The workpiece roughness and circularity were measured using a profilometer and a form error measuring machine. The measurements provided the data to identify the boring bar levels of stability, and the workpiece micro and macro geometric errors. The experiments allowed to conclude that, for all toolbars, the evaluated errors kept constant with increasing L/D ratio during stable clamping conditions, without any vibration. On the other hand, higher values of overhangs, limited to L/D>4.25 for steel tool, can cause serious damages in the cutting system if the antivibration tools or the carbide will be not used.

This paper reviews the effects of iron-based powder on shape accuracy of injection moulded parts. Analysed specimens were produced on a micro injection moulding machine. At first, specimens of pure polypropylene (PP) were manufactured. Then specimens containing 1, 2 and 3 vol. % of iron powder additive were produced using the same process parameters. Subsequently, the samples were scanned using scanned using Zeiss METROTOM CT scanner. Results were analysed via CAE inspection tools. The main aim was to compare the shape and flatness of the scanned specimens to the nominal models. Results showed that iron-based additives of this vol.% had no significant effect on shape accuracy of produced parts. This paper is a partial result of the ongoing research focused on effect of iron and steel-based additives on material, magnetic and mechanical properties of polymers.

In recent times, demand for sustainable products and systems keeps increasing. It is guided by need for reduction of energy and material consumption. Powder metallurgy (PM) has generally lower energy consumption and higher material yield than other conventional processes, such as casting, forming and machining. Also some additive manufacturing (AM) techniques use metal powder as feedstock. In this paper, the energy consumption and material yield of AM techniques using metal powders are compared with conventional manufacturing.

This paper focuses on virtual commissioning of a robotic manufacturing system, its theoretical background, and an analysis of its importance in the design of automated and robotic systems. Virtual commissioning allows the PLC control program to be tested and debugged on a created digital model of the machine, called a digital twin of the machine. Just this solution can simulate and optimize the automated system design itself without the need to have real hardware (PLC, automation elements, or the whole machine/equipment). Virtual commissioning offers an effective alternative to reduce the risks and effort of real commissioning of the machine. This makes it possible to reduce the time to market and increase flexibility, efficiency, and quality. Virtual commissioning in a single-control system is a simple solution; we can either use the Software-in-the-Loop method with emulated PLC control, simulated behavioural model, and co-simulation model or Hardware-in-the-Loop method with real controller. The problem appears when we have various types of controller, including an industrial robot controller. The paper deals with the theoretical background and partial outlines of solutions in the use of different types of the control system, if interconnections or emulators for different control systems are available. The recommended solution is to use a separate solution for the 3D simulation of the robotic system and an independent solution for the behavioural model, which will be tested in the future.

This paper focuses on the input parameters that affect the resulting efficiency of a robotic workplace for industrial use. The aim of the investigation was to find which parameters most significantly affect cycle time and electricity consumption, and which way of movement is the most suitable for robotic operation. By finding the most suitable parameters, we obtain the information on how to build the most efficient robotic workplace. The investigation focused mainly on the energy consumption and layout of the robotic work cells components that significantly affect the cycle time and potentially save electric energy.

Titanium grade 2 plates were modified by a pulsed nanosecond laser beam. The aim was to determine the surface properties after the machining process in two different liquid media. The samples were processed in distilled water and paraffin oil. It was found that a surface with half-surface roughness values with a number of cracks was formed in distilled water. The presence of water reduced the size of the heat-affected zone.

Digitalization is a hot topic today in every business, affecting the whole life cycle of a process or a product. This paper focuses on the design phase of automation systems, especially creating a digital twin of a machine to support the software development of the control system and its virtual commissioning. Different simulation model architectures are introduced, as well as specific use-case. The main objective of this paper is to present three basic types of digital twin architectures for virtual commissioning of production devices and systems. These architectures were investigated and built based on predefined requirements. Collaborative project work for the development of the digital twin and efficiency was defined as one of the requirements. Efficiency is required due to the software and hardware used for the digital twin. Architectures such as centralized, basic distributed and completely distributed were introduced in the paper. Based on the results from observation and testing, the authors recommend using the concept of completely distributed architecture of the digital twin based on the defined requirements. This digital twin architecture separates mechanical engineering and automation engineering with respect to PC stations. Nevertheless, it interconnects them using the standard machine-to-machine software and communication interfaces.