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Volume 28 (2020): Edition 47 (September 2020)

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Volume 27 (2019): Edition 45 (September 2019)

Volume 27 (2019): Edition 44 (June 2019)

Volume 27 (2019): Edition s1 (December 2019)
Special Number

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Volume 24 (2016): Edition 37 (June 2016)

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Volume 23 (2015): Edition s1 (August 2015)
Edition Title: Special number

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Special Edition

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CO-MAT-TECH 2012

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Détails du magazine
Format
Magazine
eISSN
1338-0532
Première publication
03 Mar 2011
Période de publication
2 fois par an
Langues
Anglais

Chercher

Volume 28 (2020): Edition 47 (September 2020)

Détails du magazine
Format
Magazine
eISSN
1338-0532
Première publication
03 Mar 2011
Période de publication
2 fois par an
Langues
Anglais

Chercher

9 Articles
Accès libre

Process Schedule of Material Flow Activities in iCIM 3000

Publié en ligne: 12 Dec 2020
Pages: 1 - 10

Résumé

Abstract

When the modeling production or assembly processes, it is decisive to choose the type of model that allows the process to be simulated as efficiently as possible. The technical preparation of production must respect the impact of randomly changing the order conditions and, at the same time, specific working conditions. The complexity of such a system can be modelled using simulation models. These simulation models can be designed based on the work algorithm of the production line in question. An algorithm is a finite sequence of well-defined instructions to accomplish a task. The final solution to the concept of a flexible production and assembly system will be to design a simulation model; algorithm is part of this simulation study.

Mots clés

  • Flow chart
  • simulation model
  • production system
  • assembly system
  • material flow
Accès libre

Experimental Investigation of Wearing Grinding Wheels After Machining Sintered Carbide

Publié en ligne: 12 Dec 2020
Pages: 11 - 20

Résumé

Abstract

Solid cutting tools are widely applied in the machining of shape parts and mainly fabricated using the grinding operations. Solid cutting tools are of specific geometry and shape. The tool geometry is created by mutual movement grinding wheels and stock. In the grinding of its manufacturing, grinding wheels are worn out gradually with the grinding number increasing. The wearing grinding wheel has a significant influence on the accuracy geometry of the tool produced. The paper focuses on the wear of the grinding wheels based on diamonds, and the grinding wheels based on cubic boron nitride. The wear rate of the grinding wheels is affected by the properties of a grinding wheel, grinding conditions, and type of cutting material. A measure of the ability of a grinding wheel to remove material is given by the Grinding ratio. The grinding ratio (G ratio) is defined as the volume of material removed (Vw) divided by the volume of wheel wear (Vs). Periphery grinding wheels were used in the experiments. Cylindrical face grinding was used for the machining of sintered carbide stock with a diameter of 20 mm. The results of the experiment show that the diamond-based grinding wheels are more suitable for grinding sintered carbide.

Mots clés

  • Grinding ratio
  • grinding wheel
  • grinding
  • sintered carbide
Accès libre

Design of Single-Purpose Milling Machine Prototype and its Verification With Respect to Defined Criteria

Publié en ligne: 12 Dec 2020
Pages: 21 - 31

Résumé

Abstract

The application of individual components in the milling machine design must be monitored because of the mechanical load affecting individual parts. For this reason, defined and monitored parameters within the design include, for example, individual fixed elements, the acting forces and the material properties of individual parts. In fact, the material properties are one of the main criteria included in the control calculations and numerical simulations that were developed to verify the proposed structure.

Mots clés

  • Portal milling machine
  • input parameters
  • design process
  • milling machine design
  • static strength analysis
Accès libre

Effect of the Friction and Reduction Angle on the Accuracy of Cold Drawing Steel Tubes STL Model Based on FEM Analysis

Publié en ligne: 12 Dec 2020
Pages: 32 - 39

Résumé

Abstract

The object of the study was to create a computer model that resembles the process of cold drawing seamless steel tubes, and evaluate the influence of selected process parameters on selected final dimensions and tolerances of STL models of the tubes obtained from DEFORM simulation software. The STL models of tubes generated from the simulations were evaluated, and the effects of the reduction angle and the friction coefficient on the inner/outer diameter, inner/outer roundness and concentricity were subsequently found. It was proven that the inner and outer diameters are not influenced by different values of the friction coefficient at the same reduction angle. On the other hand, increasing value of the reduction angle affects decrease of the outer and inner diamaters after drawing. Furthermore, this experimental investigation vindicates that friction coefficient and reduction angle have the minimal impact on the inner/outer roundness and outer concentricity.

Mots clés

  • Cold drawing
  • tube
  • nib
  • dimensions
  • tolerances
  • simulation
  • Finite Element Model
Accès libre

Comparison of Foundry Industry in Slovakia and Czech Republic

Publié en ligne: 12 Dec 2020
Pages: 40 - 47

Résumé

Abstract

Foundry industry is an important supplier of complex shape parts for other industrial branches. It depends on the development of customer demand in other industries. The current paper compares the structure and sales of foundry industry in Slovakia and Czech Republic.

Mots clés

  • Foundry
  • casting
  • ferrous metals
  • non-ferrous metals
Accès libre

Comparison of Foundry Industry in Slovakia and Hungary

Publié en ligne: 12 Dec 2020
Pages: 48 - 55

Résumé

Abstract

Foundry industry is an important supplier of complex shape parts for other industrial branches. It depends on the development of customer demand in other industries. The following paper compares the structure and sales of foundry industry in Slovakia and Hungary.

Mots clés

  • Foundry
  • casting
  • ferrous metals
  • non-ferrous metals
Accès libre

Influence of Surface Roughness on Selected Geometric Characteristics of Laser Beam Welded Joints of AW 2099 Alloy

Publié en ligne: 12 Dec 2020
Pages: 56 - 64

Résumé

Abstract

Al-Li alloys are used in various industries owing to their good mechanical and physical properties. However, one of the limiting factors of welding the aluminium alloys by laser beam is the high reflectivity of the beam and thus the reduced efficiency of the laser. Reduction of reflectivity can be achieved by increasing the surface roughness, which may have a beneficial effect on the absorption of the laser, resulting into affecting the weld bead dimensions. The paper deals with the analysis of the influence of surface roughness of welded materials on geometry of welded joints. Specimens of AW 2099 alloy 2099 with a thickness of 3 mm were milled to achieve different levels of roughness, and then laser welded. Characteristic dimensions of the welds (weld surface/root width) were measured. The obtained data were statistically analysed using the ANOVA method, in order to assess statistical significance of the influence of individual roughness parameters on the geometric characteristics of welds. The results of the analysis showed that, within the monitored range and surface roughness parameters, only the influence of roughness parameter Rq, Rz on the weld root width can be considered statistically significant.

Mots clés

  • Laser welding
  • AW 2099
  • geometric characteristics
  • ANOVA
Accès libre

Use of Nesting Workstations in Assembly

Publié en ligne: 12 Dec 2020
Pages: 65 - 71

Résumé

Abstract

Over the years there has been a fixed idea that components just enter the assembly floor and that assembled products leave it subsequently after certain operations have been executed on such products. Besides, there is a common notion that only small and simple products can be assembled on the so called “assembly nests”; however, the dimensions of objects assembled inside these keep increasing. Nowadays, even an aircraft, a boat, etc. can also be assembled on a moving trolley. This is possible given to the fact that the trolley with the product and with the operators themselves may come to the same storage of parts, while the system does not need to be balanced in time. On the other hand, in assembly nested layouts, the productivity of one operator is usually higher than the productivity on the line station and this because such lines are not often time balanced. Besides, this is also enhanced by the fact that more than one operator can work on a single nest. In this regard, the present paper seeks to identify the ways of combining or assembling components into products, and to analyse quality of the abovementioned assembly approaches.

Mots clés

  • Assembly systems
  • assembly nest
  • assembly configurations
Accès libre

The Effect of the Shielding Gas Flow Rate on the Geometry, Porosity, Microstructure and Mechanical Properties of Laser Weld Joints

Publié en ligne: 12 Dec 2020
Pages: 72 - 85

Résumé

Abstract

In this research, studied was the microstructure of AW5083 aluminium alloy butt laser weld joint fabricated under the Ar + 30 vol. % He shielding gas. The light and electron microscopy, computed tomography, microhardness measurements and tensile testing were used for evaluation of the weld joint properties. Porosity volume in the weld metal (WM) was observed by the computed tomography (CT). The volume of porosity in the weld No. 1 was 0.05 mm3, while that in the weld No. 2 was 1.45 mm3. The width of the weld No. 1 was 4.69 mm, the average tensile strength was 309 MPa, and the average microhardness was 55.7 HV0.1. Polyhedral grains with an average grain size diameter of 48 μm were present in the heat-affected zone. The fusion zone (FZ) was of a dendritic structure with an average grain size of 20 μm. Three intermetallic compounds β-Al3Mg2, γ-Al12Mg17 and Al49Mg32, which were identified by transmission electron microscope (TEM) analysis, were present in inter-dendritic areas of the WM. The weld joint was characterized by ductile fracture in the base metal (BM). In the FZ, a small number of Al2O3 particles of irregular shapes were observed.

Mots clés

  • Laser welding
  • aluminium alloy
  • microstructure
  • TEM analysis
9 Articles
Accès libre

Process Schedule of Material Flow Activities in iCIM 3000

Publié en ligne: 12 Dec 2020
Pages: 1 - 10

Résumé

Abstract

When the modeling production or assembly processes, it is decisive to choose the type of model that allows the process to be simulated as efficiently as possible. The technical preparation of production must respect the impact of randomly changing the order conditions and, at the same time, specific working conditions. The complexity of such a system can be modelled using simulation models. These simulation models can be designed based on the work algorithm of the production line in question. An algorithm is a finite sequence of well-defined instructions to accomplish a task. The final solution to the concept of a flexible production and assembly system will be to design a simulation model; algorithm is part of this simulation study.

Mots clés

  • Flow chart
  • simulation model
  • production system
  • assembly system
  • material flow
Accès libre

Experimental Investigation of Wearing Grinding Wheels After Machining Sintered Carbide

Publié en ligne: 12 Dec 2020
Pages: 11 - 20

Résumé

Abstract

Solid cutting tools are widely applied in the machining of shape parts and mainly fabricated using the grinding operations. Solid cutting tools are of specific geometry and shape. The tool geometry is created by mutual movement grinding wheels and stock. In the grinding of its manufacturing, grinding wheels are worn out gradually with the grinding number increasing. The wearing grinding wheel has a significant influence on the accuracy geometry of the tool produced. The paper focuses on the wear of the grinding wheels based on diamonds, and the grinding wheels based on cubic boron nitride. The wear rate of the grinding wheels is affected by the properties of a grinding wheel, grinding conditions, and type of cutting material. A measure of the ability of a grinding wheel to remove material is given by the Grinding ratio. The grinding ratio (G ratio) is defined as the volume of material removed (Vw) divided by the volume of wheel wear (Vs). Periphery grinding wheels were used in the experiments. Cylindrical face grinding was used for the machining of sintered carbide stock with a diameter of 20 mm. The results of the experiment show that the diamond-based grinding wheels are more suitable for grinding sintered carbide.

Mots clés

  • Grinding ratio
  • grinding wheel
  • grinding
  • sintered carbide
Accès libre

Design of Single-Purpose Milling Machine Prototype and its Verification With Respect to Defined Criteria

Publié en ligne: 12 Dec 2020
Pages: 21 - 31

Résumé

Abstract

The application of individual components in the milling machine design must be monitored because of the mechanical load affecting individual parts. For this reason, defined and monitored parameters within the design include, for example, individual fixed elements, the acting forces and the material properties of individual parts. In fact, the material properties are one of the main criteria included in the control calculations and numerical simulations that were developed to verify the proposed structure.

Mots clés

  • Portal milling machine
  • input parameters
  • design process
  • milling machine design
  • static strength analysis
Accès libre

Effect of the Friction and Reduction Angle on the Accuracy of Cold Drawing Steel Tubes STL Model Based on FEM Analysis

Publié en ligne: 12 Dec 2020
Pages: 32 - 39

Résumé

Abstract

The object of the study was to create a computer model that resembles the process of cold drawing seamless steel tubes, and evaluate the influence of selected process parameters on selected final dimensions and tolerances of STL models of the tubes obtained from DEFORM simulation software. The STL models of tubes generated from the simulations were evaluated, and the effects of the reduction angle and the friction coefficient on the inner/outer diameter, inner/outer roundness and concentricity were subsequently found. It was proven that the inner and outer diameters are not influenced by different values of the friction coefficient at the same reduction angle. On the other hand, increasing value of the reduction angle affects decrease of the outer and inner diamaters after drawing. Furthermore, this experimental investigation vindicates that friction coefficient and reduction angle have the minimal impact on the inner/outer roundness and outer concentricity.

Mots clés

  • Cold drawing
  • tube
  • nib
  • dimensions
  • tolerances
  • simulation
  • Finite Element Model
Accès libre

Comparison of Foundry Industry in Slovakia and Czech Republic

Publié en ligne: 12 Dec 2020
Pages: 40 - 47

Résumé

Abstract

Foundry industry is an important supplier of complex shape parts for other industrial branches. It depends on the development of customer demand in other industries. The current paper compares the structure and sales of foundry industry in Slovakia and Czech Republic.

Mots clés

  • Foundry
  • casting
  • ferrous metals
  • non-ferrous metals
Accès libre

Comparison of Foundry Industry in Slovakia and Hungary

Publié en ligne: 12 Dec 2020
Pages: 48 - 55

Résumé

Abstract

Foundry industry is an important supplier of complex shape parts for other industrial branches. It depends on the development of customer demand in other industries. The following paper compares the structure and sales of foundry industry in Slovakia and Hungary.

Mots clés

  • Foundry
  • casting
  • ferrous metals
  • non-ferrous metals
Accès libre

Influence of Surface Roughness on Selected Geometric Characteristics of Laser Beam Welded Joints of AW 2099 Alloy

Publié en ligne: 12 Dec 2020
Pages: 56 - 64

Résumé

Abstract

Al-Li alloys are used in various industries owing to their good mechanical and physical properties. However, one of the limiting factors of welding the aluminium alloys by laser beam is the high reflectivity of the beam and thus the reduced efficiency of the laser. Reduction of reflectivity can be achieved by increasing the surface roughness, which may have a beneficial effect on the absorption of the laser, resulting into affecting the weld bead dimensions. The paper deals with the analysis of the influence of surface roughness of welded materials on geometry of welded joints. Specimens of AW 2099 alloy 2099 with a thickness of 3 mm were milled to achieve different levels of roughness, and then laser welded. Characteristic dimensions of the welds (weld surface/root width) were measured. The obtained data were statistically analysed using the ANOVA method, in order to assess statistical significance of the influence of individual roughness parameters on the geometric characteristics of welds. The results of the analysis showed that, within the monitored range and surface roughness parameters, only the influence of roughness parameter Rq, Rz on the weld root width can be considered statistically significant.

Mots clés

  • Laser welding
  • AW 2099
  • geometric characteristics
  • ANOVA
Accès libre

Use of Nesting Workstations in Assembly

Publié en ligne: 12 Dec 2020
Pages: 65 - 71

Résumé

Abstract

Over the years there has been a fixed idea that components just enter the assembly floor and that assembled products leave it subsequently after certain operations have been executed on such products. Besides, there is a common notion that only small and simple products can be assembled on the so called “assembly nests”; however, the dimensions of objects assembled inside these keep increasing. Nowadays, even an aircraft, a boat, etc. can also be assembled on a moving trolley. This is possible given to the fact that the trolley with the product and with the operators themselves may come to the same storage of parts, while the system does not need to be balanced in time. On the other hand, in assembly nested layouts, the productivity of one operator is usually higher than the productivity on the line station and this because such lines are not often time balanced. Besides, this is also enhanced by the fact that more than one operator can work on a single nest. In this regard, the present paper seeks to identify the ways of combining or assembling components into products, and to analyse quality of the abovementioned assembly approaches.

Mots clés

  • Assembly systems
  • assembly nest
  • assembly configurations
Accès libre

The Effect of the Shielding Gas Flow Rate on the Geometry, Porosity, Microstructure and Mechanical Properties of Laser Weld Joints

Publié en ligne: 12 Dec 2020
Pages: 72 - 85

Résumé

Abstract

In this research, studied was the microstructure of AW5083 aluminium alloy butt laser weld joint fabricated under the Ar + 30 vol. % He shielding gas. The light and electron microscopy, computed tomography, microhardness measurements and tensile testing were used for evaluation of the weld joint properties. Porosity volume in the weld metal (WM) was observed by the computed tomography (CT). The volume of porosity in the weld No. 1 was 0.05 mm3, while that in the weld No. 2 was 1.45 mm3. The width of the weld No. 1 was 4.69 mm, the average tensile strength was 309 MPa, and the average microhardness was 55.7 HV0.1. Polyhedral grains with an average grain size diameter of 48 μm were present in the heat-affected zone. The fusion zone (FZ) was of a dendritic structure with an average grain size of 20 μm. Three intermetallic compounds β-Al3Mg2, γ-Al12Mg17 and Al49Mg32, which were identified by transmission electron microscope (TEM) analysis, were present in inter-dendritic areas of the WM. The weld joint was characterized by ductile fracture in the base metal (BM). In the FZ, a small number of Al2O3 particles of irregular shapes were observed.

Mots clés

  • Laser welding
  • aluminium alloy
  • microstructure
  • TEM analysis

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