Machines. Technologies. Materials.
Vol. 18 (2024), Issue 9

Table of Contents

  • MACHINES

    • Design of an Industry 4.0-Based, Vertically Angular Automated Line Separator

      pg(s) 278-281

      In this study, an original design was developed to address the issue of insufficient packaging speed, a key challenge in wet wipe production lines. A separator/distributor was developed that enables a single wet wipe machine to work with three packaging units during the transfer of products from the wet wipe preparation unit to the packaging process. The developed separator moves angularly on the vertical axis and can transfer products to conveyor groups leading to three different packaging lines. Additionally, a unique movable upper conveyor was designed to operate across a range of product heights, which applies pressure to the products during movement to prevent them from scattering. One of the primary design criteria for the conveyor is lightweight construction, and this was a key focus during development. To achieve angular motion, a servo-driven flywheel mechanism was designed. The machine is equipped with sensors for Industry 4.0 compatibility, ensuring communication between units. In case one of the packaging machines becomes inactive, the separator automatically redirects the product feeding process to the remaining packaging machines, ensuring uninterrupted production.

    • Dynamic analysis of vehicles hydraulic lift for the case of load handling

      pg(s) 282-285

      The paper examines the dynamic analysis of a hydraulic lift that is used for lifting and lowering vehicles. These lifts are implemented in various servicing facilities for the repair of vehicles. The lifts consist of various mechanical and hydraulic parts and besides lifting and lowering the vehicle, they need to keep the vehicle lifted for a certain amount of time. During the work operations, the lift’s main parts are heavily loaded. The method of analysis consists of 3D modeling of the Hydraulic lift and carrying simulations with software. This enables to analyze the dynamics of motion, identify the forces and stresses in lift parts and the form and intensity of oscillations that can cause failures of parts and concerns about the safety. Conclusions from this paper will be useful regarding the loading dynamics on the Hydraulic Lift during lifting and lowering, and design considerations. Results will be shown in graphical form, in time dependence. The Hydraulic Lift is modeled based on the Data from the standard manufacturer. The software that will be used for modelling and analysis is SimWise 4D.

    • Determination of dynamic loads during operation of a flexible screw sectional working body

      pg(s) 286-289

      The article presents the design of a flexible screw sectional working body that will improve the functional and operational characteristics of screw conveyors during the utilization of the removed contaminated soil layer. A mathematical model of the dynamic system of a flexible screw conveyor was created, and dynamic starting torques were calculated at the rated load of the loaded screw and when the system was braked. The analysis of the results shows that with significant damping coefficients, the startup transient process is smooth and the load reaches its nominal value without fluctuations in torque and speed.

  • TECHNOLOGIES

    • Technologies for additive manufacturing of metal structures

      pg(s) 290-293

      Additive manufacturing (AM) of metal structures is transforming industries by enabling the creation of complex, efficient, and customizable components. This article explores key AM technologies for metals, including Powder Bed Fusion (PBF), Directed Energy Deposition (DED), Binder Jetting, Metal Extrusion, and Sheet Lamination. Each is analyzed in terms of principles, strengths, limitations, and applications. A comparative evaluation highlights factors like precision, scalability, cost, and environmental impact to identify optimal technologies for various industries. Despite its advantages, challenges remain in material quality, process reliability, cost, and certification. Emerging trends such as hybrid manufacturing, AI-driven process optimization, advanced materials, and sustainable practices hold promise for overcoming these barriers. By examining current technologies and future opportunities, this article provides valuable insights for advancing metal AM in diverse applications.

    • Possible energy savings in passenger elevators

      pg(s) 294-297

      Paper deals with determining the possible savings of electrical energy in a passenger elevator. After carrying out calculations with a set number of floors of an administrative building and number of passengers according to a proven and widely used methodology in Bulgaria, an appropriate three-phase squirrel-cage induction motor has been selected to drive the considered elevator system. Calculations have been also carried out on the possible recovery, i.e. returning electrical energy back to the supply power grid when the driving rotating electrical machine is switched to generator mode. Variants with different number of passengers and movement of the cabin in upward and downward directions were theoretically studied. The active power, time to work in recovery mode and the active energy returned to the power grid are defined for each specific case. Calculations of possible electrical energy return in generator mode would be of interest to specialists dealing with these technical facilities.

    • Investigation and analysis of tested plastic films according to ASTM D6992 Standard Test Method for Accelerated Tensile Creep using the Stepped Isothermal Method

      pg(s) 298-300

      In the article, experimental results according to ASTM D6992 standard test method for accelerated tensile creep of plastic films were investigated and analyzed. A regression model was created based on the obtained results. Real and theoretical data were compared. In order to determine deviations of the model and what is the reliability of the theoretical data.

  • MATERIALS

    • Frost resistance of hollow ceramic structural elements for ceramic beehives

      pg(s) 301-303

      In laboratory conditions, the frost resistance of hollow ceramic samples (constructive elements of ceramic beehives) was examined by applying a standardized methodology for assessing the reliability of ceramic products. For both sample types that were investigated (each with different phase compositions), the result for the frost resistance coefficient Kfr is above 84%. The products retain their structural integrity and high resistance in an extreme temperature environment. It was not observed any significant damage that could disrupt their functionality. The obtained results prove the assumptions that the ceramic beehives are appropriate for use in vast geographical regions characterized by critical temperatures and high diurnal and seasonal temperature amplitudes. At the same time, the experimental data can serve for further optimization of the recipe compositions, the technological regime, and for improvements of the construction characteristics of the ceramic elements that build the ceramic beehive.

    • Investgation properties of part – holder of breaking shoe beam made of SG60/SE300 steel cast

      pg(s) 304-307

      The main reason to perform this research investigation was to find a reason for appearing failures in exploratory condition of a part holder of breaking shoe beam. This part is incorporated in an assembly in railway wagon. This part together with few others was damaged in exploratory condition. It means that cracks were noticed on these parts. Some parts were completely broken. Because of that purchaser of parts complained of received parts to the producer. One of these parts was delivered to Prof Cvetkovski to find a reason and to give opinion about the reason for failure. The damaged parts are made of cast steel SG60/SE300. Many types of investigation was performed in order to solve this problem. As first visual control was done. After that, radiographic control was made. Investigations continued with determination of chemical composition and macro and micro metallography and determination of non-metallic inclusions. Finally mechanical testing like tensile testing, hardness measurement and impact toughness were performed too. Performed research confirmed that typical casting defects in the investigated part like the hot tears, slag inclusions, shrinkage porosity and segregation are the main reasons for failure of the delivered parts, holder of breaking shoes i.e. appearing of cracks or their completely fracture.

    • Lazer ablation in liquid as innovative method for preparation of ZnO-zeolite nanocomposites

      pg(s) 308-310

      Laser ablation in liquid is an eco-friendly and efficient method to produce nanomaterials with interesting properties in a laboratory scale. Previously reported ZnO nanoparticles, obtained by nanosecond and millisecond pulsed laser under various laser parameters, demonstrated photocatalytic, gas-sensing, and antibacterial activity. Here we explore the possibility for laser ablation of Zn metal plate in natural zeolite suspension and isolation of a composite ZnO-Zeo. It was characterized by UV-vis, XPS and SEM methods. The characteristic UV-vis peak for ZnO nanoparticles was observed at 340 nm, which is associated with small particles size, proven by SEM images to be 30-50 nm. The spherical ZnO particles are located on the zeolite surface. It was found that the attraction forces between both phases cause a shift in Zn 2p XPS peak positions which were determined at 1022.0 eV and 1045.1 eV for 2p3/2 and 2p1/2 levels, respectively. The approach for laser ablation in suspension could open avenue for simultaneous formation and incorporation of various nanoparticles into different supports.