Machines. Technologies. Materials.
Vol. 16 (2022), Issue 6

Table of Contents

  • MACHINES

    • Analysis of an existing gantry crane track on assembly base

      pg(s) 189-191

      The assembly base is a permanent building site, where the elements of the track panel are assembled. It is characterized by large dimensions and weights of the processed parts and the final product. The report is based on observation and measurements of the existing assemble base in Kazichane and possibilities of modern computer technologies for modeling and simulation of the operation of the individual crane track elements. The unique of the studied crane track is that the rails are joined to half-sleepers lying on 1 m distance, not to a continuous beam, like in crane tracks in industry, and that the using materials are typical for the railway superstructu re.

    • Development of innovative commercial dishwasher using gas-heated water for energy efficiency

      pg(s) 192-194

      Commercial dishwashers are among the most important products for commercial kitchen personnel as they clean dirty products (plates, glasses, cutlery, etc.) in a short time (between 1 and 4 minutes according to the program). In recent years, customers’ demands for energy-saving products have been increasing. Therefore, instead of using the electrical energy to be obtained after the combustion of natural gas in power plants, the use of direct natural gas in a commercial dishwasher contributes to reducing the carbon footprint. In this study, the original design studies of the combustion system of the innovative commercial dishwasher prototype using water heated with gas were carried out. For the first time in our country, the system that enables the heating of water with gas was designed as a module other than the existing commercial dishwasher. An independent combustion system has been developed to provide easy use to other commercial dishwashers on the market. Simulation studies have been used effectively in the design verification phase in order to provide the most efficient combustion conditions for different gases (natural gas and LPG) in the original designed combustion system. Combustion analyses were carried out by parametric study for different operating conditions. In the innovative commercial dishwasher prototype that uses water heated with gas, optimum temperature values have been obtained for effective washing at the water inlet and water outlet points of the uniquely designed combustion system. As a result of the tests and evaluations, the most effective working range of the innovative prototype was determined.

  • TECHNOLOGIES

    • The change of microgeometry of metal surface after application of chemical pretreatments

      pg(s) 195-198

      Currently, one of the most important and monitored surface properties is the ability to achieve the highest possible level of adhesion after applying a layer of paint or glue. To guarantee this property, it is extremely important to choose the right surface pretreatment. The paper is focused on chemical surface pretreatment and subsequent evaluation of morphological surface changes after application of various selected types of chemical pretreatment based on roughness parameters.

    • Effect of Overlay Paper Properties on the Surface Quality of Laminate Flooring

      pg(s) 199-201

      In this study, the effect of overlay paper properties on the surface quality of laminate flooring was investigated. For this aim, only the upper surface of 22 gr/m² raw overlay papers impregnated with 53% melamine formaldehyde resin in the glue pool was sprinkled by corundum (Al2O3) in two different ratios (23 and 28 gr/m²) from different companies at 140-160 ºC. In the drying ovens, the impregnated overlay papers with a final weight of 135 and 140 gr/m² and a humidity of 7.5% were produced. The panels obtained at the end of these processes were tested according to TS-EN 14323 and related standards, which are surface quality features such as surface abrasion, surface scratch and ash test. According to the test results, it has been observed that under the same pressing conditions, different corundum type and amount as well as laminate floorings covered with overlay papers with different final weights have an effect on the surface quali ty properties. It was observed that although the increase in the amount of corundum did not have a significant effect on surface scratching, it had a significant effect on surface wear values. According to the results of the ash test, it was observed that the amount of corundum increased and its distribution on the overlay paper surface was homogeneous.

    • Opportunities to improve product quality with the support of industrial robots

      pg(s) 202-205

      In the industry, the concept of “production quality” means a very important and inseparable role, which has a large share in the final quality of the product. Various factors affect product quality. Above all, state-of-the-art technologies are used in every industry, which helps to adapt quickly and efficiently to changes in market conditions, which has a significant impact on the competitiveness of manufacturers to become market leaders. The manufacturers ‘efforts are made to produce a flawless product that will excessively meet customers’ requirements for the perfect product. An integral part of the production process is the quality control of products at certain stages of production. Measurement requirements are defined by satisfactory accuracy, variability, total cost and speed. An important factor in product inspection is currently the creation of a three-dimensional virtual model of a real product, where you can easily compare the created 3D model with the original CAD model and display dimensional deviations.

    • Optical tool condition monitoring techniques in milling process

      pg(s) 206-209

      Recent most important improvements in metal cutting industry are utilization of cutting tool and tool condition monitoring systems. These systems help to prevent damage to both machine tools and workpieces. New technologies in optical measurements allow construction of tool condition monitoring systems which does not affect manufacturing processes and are relatively cheap to build because of low prices of optical sensors compared to standard sensors and measurement techniques, built on cutting machines. Our paper summaries various monitoring methods for tool condition monitoring in the milling processes that use optical sensors and optical methods combined with machine vision and image processing, that have been practiced and described in literature.

    • Method for deposition of thin films from ceramics with high dielectric permittivity on metal plates

      pg(s) 210-212

      There has been growing interest in the use of the sol-gel approach to form high-quality dielectric materials. Their tailored properties allow for developing functional electronic devices in a scalable and rapid manner. According to physicochemical principles, the displacement and response behavior of charges under an applied external field can manifest in unique dielectric properties, providing useful information to improve the process, design, and quality of electronic devices. Therefore, a systematic and in-depth investigation of the fundamentals of sol-gel dielectrics is necessary. In this Research Update, we present recent advances in various sol-gel-processed dielectric materials and their applications to functional electronic devices. A brief introduction to sol-gel chemistry to form oxide dielectric films and the basis of physical mechanisms under electrical fields are discussed. Along with the dielectric properties, recent achievements of proofof-concept experiments and their various applications to functional electronic devices are introduced. It is expected that further innovations in solution-processed metal oxide dielectrics will achieve cost-effective high-performance functional electronics in the near future.

  • MATERIALS

    • Determination of the quality of renovation layers in tribological conditions

      pg(s) 213-216

      Molds designed for high-pressure casting of aluminum are exposed to very intense thermal, mechanical but also chemical stress during their operation. This stress leads to a synergistic effect of a combination of high-temperature corrosion processes in molten metals, under real conditions associated with mechanical wear. High-temperature corrosion in the environment of liquid metals occurs in the foundry industry, when casting molten metal most often into steel molds. Repair of worn parts of molds by welding, which can be performed even after their irreversible surface degradation, is a very efficient, cost-effective and envi-ronmentally acceptable form of their maintenance, while the chemical and physical properties are welded layers if they exceed the properties of the original material.

    • Study of age hardened MS1 material after the abrasive water jet application

      pg(s) 217-220

      This contribution deals with the study of cut surface after the abrasive water jet application on the material Maraging Steel MS-1, prepared in the form of 3D printing method Direct Metal Laser Sintering. The aim of the study is to point out the morphology of the cut plane under the use of various technological parameters, like feed rate of machining and abrasive mass flow at the constant cut pressure. For the track morphology monitoring after the abrasive water jet application, scanning electron microscope SEM MIRA 3, f. Tescan, was used. For the identification of observed particles stabbed in the cut track, chemical composition EDX analysis was used.

    • Monitoring the change of corrosion resistance of HCT600X+Z galvanized steel after plastic strain

      pg(s) 221-223

      This work deals with corrosion measurements of galvanized steel HCT600X+Z subjected to progressively increasing plastic strain. The corrosion resistance measurements were carried out by non-destructive EIS (electrochemical impedance spectroscopy) test and destructive LP (linear polarization) test. As a result of the work, the measured data were analyzed and the results were processed using Nyquist diagram and Tafel analysis.

    • Hybrid reinforced concrete with controlled volume deformations for hydrotechnical facilities

      pg(s) 224-227

      The development of hydration processes in cement concrete is associated with the release of significant amounts of heat, which leads to a significant exothermic temperature increasing in the concrete body, especially valid for massive structures. This creates a temperature gradient from the inside of the array to the surface. The latter may be re lated to the development of unacceptable internal stresses, often leading to cracking, defects and reducing the durability of the facility. The report presents the individual stages of the search for an optimal technical solution for the construction of a specific hydro-technical facility – a massive hybrid reinforced trapezoidal wall of a water catchment gorge, in the area of Stara Zagora town. In the context of specified geometric dimensions of the facility, the specific features of the exothermic increase of the temperature in the concrete body as a function of the hydration processes are discussed. A reasonable choice of a specific type of cement is proposed in order to limit the amount of heat released – slag cement CEM III-A 42.5 N with a specific heat of hydration up to 280 J/g. A specific concrete mix design has been proposed, providing a balanced increase in temperature within acceptable limits, preventing cracking, in two possible scenarios – winter and summer outdoor temperature conditions. An additional advantage of the mix is the inclusion in the recipe of fiber-reinforcement and high-tech chemical admixtures – deep internal crystallization and shrinkage-compensating one. Specific calculation data for the kinetics of temperature increasing are presented, and the obtained values are critically evaluated in terms of guaranteed cracks eliminating in the structure.