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Volume 28 (2020): Issue 4 (December 2020)
Special Issue: IMTech2020-INNOVATIVE MINING TECHNOLOGIES. Editors: Dariusz Prostański, Bartosz Polnik

Volume 28 (2020): Issue 3 (September 2020)

Volume 28 (2020): Issue 2 (June 2020)

Volume 28 (2020): Issue 1 (March 2020)

Volume 27 (2019): Issue 4 (December 2019)

Volume 27 (2019): Issue 3 (September 2019)

Volume 27 (2019): Issue 2 (June 2019)
Special Issue: Technological Innovations in the Socio-Humanistic Context

Volume 27 (2019): Issue 1 (March 2019)

Volume 26 (2018): Issue 4 (December 2018)

Volume 26 (2018): Issue 3 (September 2018)

Volume 26 (2018): Issue 2 (June 2018)

Volume 26 (2018): Issue 1 (March 2018)

Volume 25 (2017): Issue 4 (December 2017)

Volume 25 (2017): Issue 3 (September 2017)

Volume 25 (2017): Issue 2 (June 2017)

Volume 25 (2017): Issue 1 (March 2017)

Volume 24 (2016): Issue 4 (December 2016)

Volume 23 (2016): Issue 3 (September 2016)

Volume 22 (2016): Issue 2 (June 2016)

Volume 21 (2016): Issue 1 (March 2016)

Journal Details
Format
Journal
eISSN
2450-5781
First Published
30 Mar 2017
Publication timeframe
4 times per year
Languages
English

Search

Volume 27 (2019): Issue 4 (December 2019)

Journal Details
Format
Journal
eISSN
2450-5781
First Published
30 Mar 2017
Publication timeframe
4 times per year
Languages
English

Search

10 Articles
Open Access

Possibilities of Pressure Die Casting of Iron Alloys

Published Online: 04 Dec 2019
Page range: 199 - 204

Abstract

Abstract

The current trends of production of casts are directed towards production of components disposing of higher accuracy, increased quality of surface and homogenous structure. In case of a thin-walled cast the development of speed of pressing and of pressure was observed inside the mould cavity during pressure die casting of ferrous alloys. In case of die casting of ferrous alloys the attention was paid to life service of a pressing piston and of a filling chamber. The optimal temperature of the steel casting ranges from 1600 to 1750°C and optimal mould temperature ranged from 220 to 260°C. The residues having occurred in gates reached the hardness of 38 HRC and in case of casts the value was of 45 HRC. Influence of acting of resistance pressure on the thin-walled casts only minimally. With the increasing resistance pressure the structure becomes more fine-grained and along with the increasing thickness of the wall the influence of the resistance pressure increases as well. Technology of pressure die casting of iron alloys can be compared with the pressure die casting technology of aluminium alloys. As standard, for pressure die casting the cast irons with carbon content of lower than 3% are recommended.

Keywords

  • pressure dies casting
  • specific pressure on metal
  • iron alloys
  • steel
Open Access

Experimental Determination of the Belt Transmission Slip

Published Online: 04 Dec 2019
Page range: 205 - 210

Abstract

Abstract

The presented paper provides the alternative options for determining the condition of belt gear based on the testing and monitoring. In order to carry out experimental measurements, a newly developed device for testing, monitoring and diagnostics of belt drives was designed, as well as the possibility of determination of limit states by extreme loads. The designed measuring stand allows to determine the point of destruction of the belt for an extreme load. The main objective of the experimental measurement was to determine the slip of the wedge-shaped belt. The slip was evaluated by the coefficient of belt creeping and the specific belt slip by means of the measuring stand. The measurements on the proposed device can be made when the input speed from the electric motor and the transmitted torque of the belt gear are constant while the tensioning force of the belt drive is changing or the measurements can be made when the tensioning force and input speed of the belt drive are constant and the torsional moment changes. The monitoring of specified parameters for determining the belt gear slip is made by means of sensors located at predetermined locations from which data is processed by a PC. In the paper, the analytical calculation is processed, from which the values are compared with the values measured on the proposed device.

Keywords

  • belt gear
  • calculation
  • measurement
  • slip
Open Access

Acoustic Emission of Corroded Weldments During Tensile Test

Published Online: 04 Dec 2019
Page range: 211 - 216

Abstract

Abstract

The article deals with the use of acoustic emission to identify the formation of cracks during the mechanical loading in the corrosive attacked weldment S235JR+N. The experiment includes the methodology for continual record of emissive signals, data analysis and monitoring of material response to monitor mechanical stress effect in real time. There is possibility to observe response of corrosive degraded samples in real time during mechanical stress through the suitably designed methodology of detection, process and analysing of acoustic emission signals. It is possible to gain new information about processes rising inside the material by this way of data measurement. The signals of acoustic emission can be used as the way of identification for the micro cracks rising in the inner and also external structure of effortful materials.

Keywords

  • weld joint
  • hot-dip galvanising
  • corrosion
  • acoustic emission
  • protection
Open Access

Properties Prediction of Linear Block-Polyurethanes Based on the Mixtures of Simple Oligoethers

Published Online: 04 Dec 2019
Page range: 217 - 220

Abstract

Abstract

Polyurethanes are materials usable in wide spectrum of applications. This article is aimed at the properties tailoring of selected polymers by an alteration in initial materials. To achieve that goal, we proposed form the polyurethane matrix by mixing materials that have a different ratio of the initial components. Mathematical model has been developed that describes relationship of structure and strength, deformation, rheological and tribotechnical characteristics of linear block-polyurethanes based on oligoether blends. Oligoethers blend samples were obtained by injection moulding on an automatic thermoplastication machine with varying proportions of the starting components over the whole concentration range. A significant change of properties over the whole concentration range was observed and compositions with unique combination of characteristics have been determined. Obtained dependencies allow to predict the composition of the binary mixture with a tailored level of strength, deformation, rheological and tribotechnical characteristics. The obtained results are fully consistent with the practical experience of processing and exploitation of initial polyurethanes.

Keywords

  • linear block-polyurethane
  • oligoether
  • physico-mechanical characteristics
  • melt flow characteristics
  • melt flow
  • wear intensity
  • material quality indicator
Open Access

Implementation of Integrated Management System in Order to Enhance Equipment Efficiency

Published Online: 04 Dec 2019
Page range: 221 - 226

Abstract

Abstract

The main aim of presented article is to present methodology how sophisticated products as compressor equipment can be considered and analysed as a complex technical system which consists of jointly operating components – a set of hardware, software, operational staff and documented information. In process modelling, these components are interacting in different processes of inputs, outputs, mechanisms (resources) or management. Based on the regulatory requirements for each component of the system, a key efficiency indicator can be identified. This allows to control the process and make appropriate decisions to improve the system. The application of the proposed methodology for the development and implementation of an integrated management system reduce the cost of resources and significantly improve the quality of the implementation of processes.

Keywords

  • complex technical system
  • integrated management system
  • standards
Open Access

Analysis of Risk Factors for Underground Coal Gasification

Published Online: 04 Dec 2019
Page range: 227 - 235

Abstract

Abstract

The purpose of this article is to determine the environmental impacts of underground gasification on the population and to analyze the risk of underground coal gasification (UCG) activities using selected risk assessment methods. Coal gas is a regular part of coal deposits and its extraction also allows the use of coal deposits that cannot be extracted by traditional methods. These technologies bring both positive and negative aspects. The paper points out the risk analysis, hazard identification and assessment during the operation of UCG technology using a risk graph and a risk matrix. Identified risks to workers that cannot be reduced should be taken into consideration and appropriate safeguard should be used. For each risk, it is necessary to inform employees about regular education and training. From worldwide experience with this technology, it is possible to analyze risks in Slovakia. Actual gasification produces polluting gases such as carbon dioxide, carbon monoxide, hydrogen sulphide, hydrogen sulphide, nitrogen oxides, tar and ash, and creates a risk that may occur on and under the surface of the site depending on the geological and hydrogeological structure of the deposits. Possible measures to mitigate the adverse effects are proposed for the implementation of this technology. Coal is still one of the main domestic primary energy sources. Currently, only 5 out of 19 deposits in the Slovak Republic are used. Underground gasification could increase the use of Slovak coal and brown coal deposits.

Keywords

  • analysis of risk
  • coal gas
  • environment
  • polluting gases
  • underground coal gasification
Open Access

Measurement of Residual Stresses of Locomotive Wheel Treads During the Manufacturing Technological Cycle

Published Online: 04 Dec 2019
Page range: 236 - 241

Abstract

Abstract

The production of two-wheeled rolling stock represents, at first glance, a simple assembly process that significantly affects the overall functionality and safety of the vehicle. This is due to residual stresses that arise after assembly by pressing the wheel on the axle. The state of stress after assembly remains in the design has a decisive influence on the load-bearing capacity of the two-wheel drive, its lifespan but also the transfer of the pulling force in the case of locomotives. Therefore, it is very important to find suitable methods for determining residual stresses. Numerical and experimental approaches are already in place to gain information on the state of stress after compression, or during a real operation. The developed techniques and tools for estimation of residual stresses in locomotive wheel treads based on the acoustoelasticity effect using electromagnetic acoustic transformation are described in the paper. The original results of residual stress measurement in the treads during a technological cycle of locomotive wheel pair manufacturing are presented.

Keywords

  • tread railway wheels
  • acoustoelasticity
  • electromagnetic acoustic transformation
  • residual stresses
Open Access

The Design of Forecasting System Used for Prediction of Electro-Motion Spare Parts Demands as an Improving Tool for an Enterprise Management

Published Online: 04 Dec 2019
Page range: 242 - 249

Abstract

Abstract

This article describes the design of a simple forecasting system and its practical application to predict the sporadic needs for a spare part. The article shows new approach already implemented in the special servicing and production company in Slovakia and its results during a short period of performance after its implementation. Such a proposed model can be a part of the purchase planning of spare parts within the company’s logistics system. In some companies, the material flow of spare parts is dominant element in terms of logistics costs. Their management is therefore important for cost optimization, customer satisfaction and market sustainability in a competitive environment. The article, in its introductory part, provides an overview of similar practical solutions within the research of this topic, but many models are designed to be applied in a global market environment and predict the amount of spare parts needed in different industries. However, these models are difficult to use for the needs of a small enterprise, because the main problem lies in the time of a spare part demand rather than its quantity. If there is a need for a specific spare part, which costs several hundred or thousands of euros, but the consumption is only a few pieces per year or more than a year, the time prediction of required spare parts is therefore crucial.

Keywords

  • forecast
  • spare parts
  • time series
  • order
  • model
Open Access

Expert Technology for Risk Management in the Implementation of QRM in a High-Tech Industrial Enterprise

Published Online: 04 Dec 2019
Page range: 250 - 254

Abstract

Abstract

In modern conditions, management technology is becoming the main instrument of competition in many areas of production and business. The article focuses on the examinations of issues related to the possibilities of introducing an integrated risk management system in modern high-tech enterprises. The main scientific research methods are bibliographic analysis, formal logic methods, comparative analysis, methods of analogies. Based on the application of the guidelines of systems’ theory, of the theory of self-organization, the theory of risk management, and the theory of reflexive control the expert technology for risk management in a high-tech industrial enterprise was developed. As a result of the study, it was revealed that the use of technologies such as the ETRM will help to increase the feasibility and effectiveness of implementing complex projects such as fast-response QRM production.

Keywords

  • effective management technology
  • risk management
  • QRM production
Open Access

Assessment of Production Process Capability in the Serial Production of Components for the Automotive Industry

Published Online: 04 Dec 2019
Page range: 255 - 258

Abstract

Abstract

The article deals with the assessment of production process capability in the serial production of plastic components. The plastic component was used for analysis. Component is used in the automotive industry in car suspension shock absorbers. Assessing the capability of the product’s manufacturing process is very important. The aim of the present paper is to measure the dimensional characteristics of a thermoplastic product as a monitored quality feature. The analyzed product is manufactured in an eightfold injection mold by injection technology. The products from each injection mold cavity were considered separately. Process capability was assessed using capability indices. Process variability and centering were evaluated. Based on the analysis we can say that the production process is in excellent condition.

Keywords

  • production process
  • capability
  • automotive industry
  • plastic components
10 Articles
Open Access

Possibilities of Pressure Die Casting of Iron Alloys

Published Online: 04 Dec 2019
Page range: 199 - 204

Abstract

Abstract

The current trends of production of casts are directed towards production of components disposing of higher accuracy, increased quality of surface and homogenous structure. In case of a thin-walled cast the development of speed of pressing and of pressure was observed inside the mould cavity during pressure die casting of ferrous alloys. In case of die casting of ferrous alloys the attention was paid to life service of a pressing piston and of a filling chamber. The optimal temperature of the steel casting ranges from 1600 to 1750°C and optimal mould temperature ranged from 220 to 260°C. The residues having occurred in gates reached the hardness of 38 HRC and in case of casts the value was of 45 HRC. Influence of acting of resistance pressure on the thin-walled casts only minimally. With the increasing resistance pressure the structure becomes more fine-grained and along with the increasing thickness of the wall the influence of the resistance pressure increases as well. Technology of pressure die casting of iron alloys can be compared with the pressure die casting technology of aluminium alloys. As standard, for pressure die casting the cast irons with carbon content of lower than 3% are recommended.

Keywords

  • pressure dies casting
  • specific pressure on metal
  • iron alloys
  • steel
Open Access

Experimental Determination of the Belt Transmission Slip

Published Online: 04 Dec 2019
Page range: 205 - 210

Abstract

Abstract

The presented paper provides the alternative options for determining the condition of belt gear based on the testing and monitoring. In order to carry out experimental measurements, a newly developed device for testing, monitoring and diagnostics of belt drives was designed, as well as the possibility of determination of limit states by extreme loads. The designed measuring stand allows to determine the point of destruction of the belt for an extreme load. The main objective of the experimental measurement was to determine the slip of the wedge-shaped belt. The slip was evaluated by the coefficient of belt creeping and the specific belt slip by means of the measuring stand. The measurements on the proposed device can be made when the input speed from the electric motor and the transmitted torque of the belt gear are constant while the tensioning force of the belt drive is changing or the measurements can be made when the tensioning force and input speed of the belt drive are constant and the torsional moment changes. The monitoring of specified parameters for determining the belt gear slip is made by means of sensors located at predetermined locations from which data is processed by a PC. In the paper, the analytical calculation is processed, from which the values are compared with the values measured on the proposed device.

Keywords

  • belt gear
  • calculation
  • measurement
  • slip
Open Access

Acoustic Emission of Corroded Weldments During Tensile Test

Published Online: 04 Dec 2019
Page range: 211 - 216

Abstract

Abstract

The article deals with the use of acoustic emission to identify the formation of cracks during the mechanical loading in the corrosive attacked weldment S235JR+N. The experiment includes the methodology for continual record of emissive signals, data analysis and monitoring of material response to monitor mechanical stress effect in real time. There is possibility to observe response of corrosive degraded samples in real time during mechanical stress through the suitably designed methodology of detection, process and analysing of acoustic emission signals. It is possible to gain new information about processes rising inside the material by this way of data measurement. The signals of acoustic emission can be used as the way of identification for the micro cracks rising in the inner and also external structure of effortful materials.

Keywords

  • weld joint
  • hot-dip galvanising
  • corrosion
  • acoustic emission
  • protection
Open Access

Properties Prediction of Linear Block-Polyurethanes Based on the Mixtures of Simple Oligoethers

Published Online: 04 Dec 2019
Page range: 217 - 220

Abstract

Abstract

Polyurethanes are materials usable in wide spectrum of applications. This article is aimed at the properties tailoring of selected polymers by an alteration in initial materials. To achieve that goal, we proposed form the polyurethane matrix by mixing materials that have a different ratio of the initial components. Mathematical model has been developed that describes relationship of structure and strength, deformation, rheological and tribotechnical characteristics of linear block-polyurethanes based on oligoether blends. Oligoethers blend samples were obtained by injection moulding on an automatic thermoplastication machine with varying proportions of the starting components over the whole concentration range. A significant change of properties over the whole concentration range was observed and compositions with unique combination of characteristics have been determined. Obtained dependencies allow to predict the composition of the binary mixture with a tailored level of strength, deformation, rheological and tribotechnical characteristics. The obtained results are fully consistent with the practical experience of processing and exploitation of initial polyurethanes.

Keywords

  • linear block-polyurethane
  • oligoether
  • physico-mechanical characteristics
  • melt flow characteristics
  • melt flow
  • wear intensity
  • material quality indicator
Open Access

Implementation of Integrated Management System in Order to Enhance Equipment Efficiency

Published Online: 04 Dec 2019
Page range: 221 - 226

Abstract

Abstract

The main aim of presented article is to present methodology how sophisticated products as compressor equipment can be considered and analysed as a complex technical system which consists of jointly operating components – a set of hardware, software, operational staff and documented information. In process modelling, these components are interacting in different processes of inputs, outputs, mechanisms (resources) or management. Based on the regulatory requirements for each component of the system, a key efficiency indicator can be identified. This allows to control the process and make appropriate decisions to improve the system. The application of the proposed methodology for the development and implementation of an integrated management system reduce the cost of resources and significantly improve the quality of the implementation of processes.

Keywords

  • complex technical system
  • integrated management system
  • standards
Open Access

Analysis of Risk Factors for Underground Coal Gasification

Published Online: 04 Dec 2019
Page range: 227 - 235

Abstract

Abstract

The purpose of this article is to determine the environmental impacts of underground gasification on the population and to analyze the risk of underground coal gasification (UCG) activities using selected risk assessment methods. Coal gas is a regular part of coal deposits and its extraction also allows the use of coal deposits that cannot be extracted by traditional methods. These technologies bring both positive and negative aspects. The paper points out the risk analysis, hazard identification and assessment during the operation of UCG technology using a risk graph and a risk matrix. Identified risks to workers that cannot be reduced should be taken into consideration and appropriate safeguard should be used. For each risk, it is necessary to inform employees about regular education and training. From worldwide experience with this technology, it is possible to analyze risks in Slovakia. Actual gasification produces polluting gases such as carbon dioxide, carbon monoxide, hydrogen sulphide, hydrogen sulphide, nitrogen oxides, tar and ash, and creates a risk that may occur on and under the surface of the site depending on the geological and hydrogeological structure of the deposits. Possible measures to mitigate the adverse effects are proposed for the implementation of this technology. Coal is still one of the main domestic primary energy sources. Currently, only 5 out of 19 deposits in the Slovak Republic are used. Underground gasification could increase the use of Slovak coal and brown coal deposits.

Keywords

  • analysis of risk
  • coal gas
  • environment
  • polluting gases
  • underground coal gasification
Open Access

Measurement of Residual Stresses of Locomotive Wheel Treads During the Manufacturing Technological Cycle

Published Online: 04 Dec 2019
Page range: 236 - 241

Abstract

Abstract

The production of two-wheeled rolling stock represents, at first glance, a simple assembly process that significantly affects the overall functionality and safety of the vehicle. This is due to residual stresses that arise after assembly by pressing the wheel on the axle. The state of stress after assembly remains in the design has a decisive influence on the load-bearing capacity of the two-wheel drive, its lifespan but also the transfer of the pulling force in the case of locomotives. Therefore, it is very important to find suitable methods for determining residual stresses. Numerical and experimental approaches are already in place to gain information on the state of stress after compression, or during a real operation. The developed techniques and tools for estimation of residual stresses in locomotive wheel treads based on the acoustoelasticity effect using electromagnetic acoustic transformation are described in the paper. The original results of residual stress measurement in the treads during a technological cycle of locomotive wheel pair manufacturing are presented.

Keywords

  • tread railway wheels
  • acoustoelasticity
  • electromagnetic acoustic transformation
  • residual stresses
Open Access

The Design of Forecasting System Used for Prediction of Electro-Motion Spare Parts Demands as an Improving Tool for an Enterprise Management

Published Online: 04 Dec 2019
Page range: 242 - 249

Abstract

Abstract

This article describes the design of a simple forecasting system and its practical application to predict the sporadic needs for a spare part. The article shows new approach already implemented in the special servicing and production company in Slovakia and its results during a short period of performance after its implementation. Such a proposed model can be a part of the purchase planning of spare parts within the company’s logistics system. In some companies, the material flow of spare parts is dominant element in terms of logistics costs. Their management is therefore important for cost optimization, customer satisfaction and market sustainability in a competitive environment. The article, in its introductory part, provides an overview of similar practical solutions within the research of this topic, but many models are designed to be applied in a global market environment and predict the amount of spare parts needed in different industries. However, these models are difficult to use for the needs of a small enterprise, because the main problem lies in the time of a spare part demand rather than its quantity. If there is a need for a specific spare part, which costs several hundred or thousands of euros, but the consumption is only a few pieces per year or more than a year, the time prediction of required spare parts is therefore crucial.

Keywords

  • forecast
  • spare parts
  • time series
  • order
  • model
Open Access

Expert Technology for Risk Management in the Implementation of QRM in a High-Tech Industrial Enterprise

Published Online: 04 Dec 2019
Page range: 250 - 254

Abstract

Abstract

In modern conditions, management technology is becoming the main instrument of competition in many areas of production and business. The article focuses on the examinations of issues related to the possibilities of introducing an integrated risk management system in modern high-tech enterprises. The main scientific research methods are bibliographic analysis, formal logic methods, comparative analysis, methods of analogies. Based on the application of the guidelines of systems’ theory, of the theory of self-organization, the theory of risk management, and the theory of reflexive control the expert technology for risk management in a high-tech industrial enterprise was developed. As a result of the study, it was revealed that the use of technologies such as the ETRM will help to increase the feasibility and effectiveness of implementing complex projects such as fast-response QRM production.

Keywords

  • effective management technology
  • risk management
  • QRM production
Open Access

Assessment of Production Process Capability in the Serial Production of Components for the Automotive Industry

Published Online: 04 Dec 2019
Page range: 255 - 258

Abstract

Abstract

The article deals with the assessment of production process capability in the serial production of plastic components. The plastic component was used for analysis. Component is used in the automotive industry in car suspension shock absorbers. Assessing the capability of the product’s manufacturing process is very important. The aim of the present paper is to measure the dimensional characteristics of a thermoplastic product as a monitored quality feature. The analyzed product is manufactured in an eightfold injection mold by injection technology. The products from each injection mold cavity were considered separately. Process capability was assessed using capability indices. Process variability and centering were evaluated. Based on the analysis we can say that the production process is in excellent condition.

Keywords

  • production process
  • capability
  • automotive industry
  • plastic components

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