MM Science Journal, June 2020

NUMERICAL SIMULATION OF COMPOSITE CAR SEAT CUSHION

Pavel Srb, Michal Petru
Keywords: numerical simulation | car seat | composite foam | natural fibers | low-density

Reduction of energy consumption, improving performance and efficiency is one of the most important factors influencing current trends in the development of components used in the transportation and automotive industry. For car producers, one of the possible ways of achieving such a goal is to reduce the weight of individual components while maintaining or improving the material properties during practic (…)

CERAMIC 3D PRINTING: COMPARISON OF SLA AND DLP TECHNOLOGIES

Veronika Truxova, Jiri Safka, Martin Seidl, Iaroslav Kovalenko, Lukas Volesky, Michal Ackermann
Keywords: 3D printing | stereolithography | Digital Light Processing | ceramics | sintering | debinding

Complex ceramic parts tend to be difficult or even impossible to produce by conventional methods. Therefore, the 3D printing technologies have started to spread widely in the area of ceramic parts production. The aim of this paper is to compare the efficiency of Stereolithography and Digital Light Processing technologies in 3D printing of ceramic parts. Firstly, indicative chemical analysis was performe (…)

COMPENSATION FOR DEVIATIONS ON CYLINDRICAL SHAPES MANUFACTURED BY 3D PRINTERS

Michal Sasala, Lukas Hrivniak, Jozef Svetlik, Peter Demec
Keywords: deviations | 3D printers | PLA | additive manufacturing

This paper compares deviations on cylindrical shapes between CAD models and parts created by additive manufacturing. These parts happen to have different dimensions than their CAD models and even counterparts designed with working precision of 3D printers do not fit together. These deviations are changing based on material and based on settings, but they are always in favor of overlapping fits. However (…)

DYNAMICAL LOAD OF LINEAR ROLLING GUIDES

Radka Jirova, Lubomir Pesik
Keywords: dynamical load | linear rolling guides | Lagrange equations | dynamical analysis | multibody systems

Linear rolling guides are used for realizing a translational motion of mechanical elements or assemblies e.g. in industrial robots, handling or CNC machines. Their reliability is highly desirable to meet the requirements of Industry 4.0, and hence the accurate load identification of linear guides is needed. The objective of this article is to identify a dynamical load of linear guides based on the subst (…)

MECHANISM OF MATERIAL REMOVAL DURING DIE-SINKING EDM OF TOOL STEEL EN 90MnCrV8

Luboslav Straka, Gabriel Dittrich
Keywords: Die-sinking Electrical Discharge Machining (Die-sinking EDM) | Electrode Wear Ratio (EWR) | Main Technological Parameters (MTP) | Material Removal Rate (MRR) Tool Wear Rate (TWR).

Mechanism of material removal after die-sinking electrical discharges machining, is quite complex. The principle is based on electrical discharge which occurs between workpiece and tool electrode. The electrical discharges always occur when complying the specific conditions, i.e. reaching the desired mutual distance (gap), mutual combination of main technological parameters and sufficient discharge ene (…)

AMONG THE WORLD’S LEADERS IN FORGING MACHINES: CKV 17000 DOOSAN PRESS

Milan Cechura, Vaclav Kubec
Keywords: hydraulic press | free forming | design | finite element method | optimization

This paper presents the largest hydraulic press for open-die forging ever made in the Czech Republic. Its capacity of 170 MN combines with a workspace of 8.5-metre height and 9.8-metre width. In each case, the result is a unique machine, a prototype made to customer requirements. Designing machines of this size always involves a great deal of ingenuity and experience which cannot be taught. The paper de (…)

POLYOXYMETHYLENE FLOW ENHANCEMENT USING THE ROUGH SURFACE INJECTION MOULD CAVITY

Petr Fluxa, Michal Stanek, Martin Ovsik, Adam Dockal
Keywords: injection moulding | polymer fluidity | surface roughness | polyoxymethylene | rheology

Injection moulding is a manufacturing process which is suitable for high-volume production of polymer parts. These products are final and do not require any additional operations. The quality of the final product is significantly affected by the surface of the mould cavity. This paper reveals the influence of cavity surface roughness and technological parameters on the flow length of polyoxymethylene (P (…)

UTILIZING INSTRUMENTED HARDNESS TEST TO MEASURE PROPERTIES OF POLYAMIDE SURFACE LAYER

Martin Ovsik, Michal Stanek, Adam Dockal, Lenka Hylova
Keywords: Polyamide 6 | radiation | cross-linking instrumented hardness | surface layer | gel content

The goal of this study was to determine the extent, to which beta radiation modified mechanical properties of surface layer on scale of nano meters. The current trend of replacing varying metal products by plastic products leads to lesser weight, but also a decrease of the tear resistance. This can be countered by exposing the material to electron radiation, which causes a creation of 3D network within (…)

METHODOLOGY OF ARM DESIGN FOR MOBILE ROBOT MANIPULATOR USING TOPOLOGICAL OPTIMIZATION

Zbynek Paska, Jaroslav Rojicek, Petr Ferfecki, Martin Fusek, Dominik Heczko, Vaclav Krys
Keywords: topology optimization | manipulator arm optimization | material model | DIC | ABS-M30 | 3D Print | FDM additive technology

The contribution deals with the problematics of topology optimization of the arm of a mobile robot manipulator for the international competition European Rover Challenge (ERC). The manipulator was designed at the Department of Robotics at VSB - TU Ostrava and is described in detail below. The aim was to test the entire design process: determination of loading forces, material model and parameters identi (…)

THE OPTIMIZATION OF OPERATING PARAMETERS FOR A MELTING FURNACE DURING MELTING OF ALUMINIUM ALLOY AlSi7Mg0.6

Luboslav Straka, Peter Michalik, Slavko Pavlenko, Matej Hrabcak
Keywords: optimization | technical device | melting furnace | operating parameters | economic efficiency

One of the key requirements for almost every technical device is its reliable, safe and economical operation. All these requirements can only be fulfilled by the appropriate choice of the individual elements of a technical device and their appropriate constructional arrangement concept. The choice of the elements of a technical device and their constructional arrangement must be done as a matter of prio (…)

MODELING WITHIN NATIONAL ECONOMY USING INDUSTRY-ORIENTED INDICATORS: EVIDENCE FROM CZECH REPUBLIC

Elena Gresova, Jozef Svetlik
Keywords: gross domestic product | multiple linear regression analysis | industry-oriented indicators | Czech Republic

The presented paper solved the question of national economy modeling with an emphasis on gross domestic product. The modeling was based especially on industry-oriented indicators and applied to the Czech Republic. The multiple linear regression analysis was used as the main research method. The main objective of this paper was to specify the relationship between the dependent variable (gross domestic pr (…)

IMPROVEMENT OF POLYMER SURFACE LAYER BY ELECTRON RADIATION

Martin Ovsik, Michal Stanek, Adam Dockal, Petr Fluxa
Keywords: radiation | electron beam | cross-linking | ultra-nano hardness | indentation

This article deals with improving properties of the surface layer of varying polymer products. The surface layer of the tested polymer was influenced by electron radiation with varying intensity. This resulted in improved resistance to wear due to the creation of a 3D network within the polymer structure. The properties were measured by an instrumented test using a contemporary ultra-nano indentation de (…)

RECONFIGURABLE WHEEL-LEGGED ROBOT

Ivan Virgala, Lubica Mikova, Tatiana Kelemenova, Michal Kelemen, Erik Prada, Darina Hroncova, Martin Varga
Keywords: legged locomotion | reconfigurable | Robot | wheeled locomotion | mechanism

The paper deals with the reconfigurable robot design. A robot should be able to locomote via using wheels on a smooth terrain and locomote via using legs on a rough terrain or if necessary also cross an obstacle. The transformation between legs and wheels is a suitable concept to an unknown environment with obstacles. Wheeled locomotion is better from the viewpoint of energy consumption. A design of a (…)

PRODUCTION LINE AUTOMATION PROJECT BASED OF FMEA METOD

Peter Malega, Naquib Daneshjo
Keywords: FMEA | production line | throttle valve | ESD floor | automation | 3D model

The main goal of this paper is to analyze production line LITROBA and propose improvements for this line. The paper is divided into three main sections. The first section consists of two smaller parts, which treat about method FMEA and about the selected product, which is the throttle valve. The second section is about branches of production line LITROBA and is concentred on the manual workstations and (…)

SHAPE AND DIMENSIONAL ANALYSIS OF LATTICE STRUCTURES PRODUCED BY SELECTIVE LASER MELTING

Radek Vrana, Ondrej Vaverka, Daniel Koutny, Katerina Docekalova, David Palousek
Keywords: Selective Laser Melting (SLM) | lattice structures | shape analysis | dimension analysis | digitization | finite element analysis

Mechanical properties of lattice structures produced by Selective Laser Melting (SLM) are hardly predictable using a numerical simulation. It is caused by procedural inaccuracies of the SLM, such as shape and dimension deviations which are usually not included in a simulation. In order to quantify their influence, lattice structure specimens were produced by SLM and digitized in the whole volume using (…)

THEORETICAL RESEARCH OF THE INTERNAL GAS DYNAMICS PROCESSES OF MEASUREMENTS OF HOT AIR CURTAIN WITH CROSS-FLOW FAN

Maria R. Koroleva, Olga V. Mishchenkova, Michal Kelemen, Alena A. Chernova
Keywords: theoretical research | air curtain | cross-flow fan | computational simulation | gas dynamic | curtain efficiency

This paper describes problems of computational simulation of gas dynamics and thermophysical processes running inside a displacement volume of the air curtain with a cross flow fan. The measurement of flow structure in the form of flow lines, gas pressure, temperature and velocity field at a fan rotation rate ranged from 250 rpm up to 1500 rpm is evaluated due to the computational experiment. The measur (…)

THE PROCESS OF CREATING A COMPUTATIONAL 3D MODEL OF A HARMONIC TRANSMISSION

Maros Majchrak, Robert Kohar, Michal Lukac, Rudolf Skyba
Keywords: Harmonic gear systems | construction parameters | 3D computational model | backlash analysis

The article focuses on the explanation of the basic principles and functions of harmonic gear systems. The main objective of the article is to comprehensively explain the relations concerning the main construction parameters of these special gear systems and their impact on the backlash. It also includes basic mathematical relationships between the reaction elements, mechanical characteristics, cogging (…)