Wyniki wyszukiwania - BazTech

1

Analyzing the use of rigid- or elastic-plastic finite models for the simulating of cutting processes

Stupnytskyy Vadym, Prodanchuk Oleh, Dyshev Oleksand

Archive of Mechanical Engineering

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2025

|

LXXII, nr 1

131--152

EN

The simulation modeling of cutting processes represents a powerful scientific instrument for investigating stress-strain and thermodynamic processes in machined materials. Nevertheless, the principal obstacle to the extensive deployment of this scientific approach is inadequate precision of the resulting research outcomes. This is due to the complexity of formalizing the physical and mechanical forming pattern, considering all the dominant factors in building a high-quality cutting model. Additionally, there is a need for professional experience from the researcher to correctly describe the physical model of the material, as well as a logical selection of fracture criteria, among other factors. One of the most significant challenges in ensuring the accuracy of cutting modeling processes is formalization of the description of a rigidplastic or elasto-plastic FEA model for analyzing the behavior of materials during machining. The article presents a scientifically based argument for the practicality of using these techniques in simulation modeling systems. It also provides practical recommendations for researchers on constructing an accurate FEA simulation model in DEFORM 2D. The conclusions drawn from the analysis of simulation studies of cutting-induced residual stresses for heterogeneous materials are confirmed by experimental investigations.

2

Mitigation of edge fracture in tempered glass during abrasive water jet cutting

Şimşi Uğur

Advances in Mechanical and Materials Engineering

|

2025

|

Vol. 42, nr 1

231--237

EN

When an 8 mm-thick glass hob plate is cut in a circular shape using high-pressure abrasive water jet cutting in two distinct sizes, it leads to issues such as breakage and burr formation along the edges. As a result, a secondary grinding process becomes necessary, which not only wastes time but also drives up the cost. Additionally, this process increases the amount of scrap material produced. The goal of this research is to optimize the cutting process by experimentally determining the parameters that affect the edge quality of the 8 mm-thick glass, specifically after adjusting the diagonality of a CNC abrasivewater jet cutting machine to improve the circularity of the cut. Various tests were conducted under different pressures, flow rates, nozzle types, orifice sizes, and garnet abrasives. The findings revealed that the most efficient and defect-free cutting conditions were achieved with a 2000 bar pressure, 0.4 kg/m abrasive flow rate, 0.76 mm nozzle, 0.25 mm orifice, 120 mesh garnet abrasive, and a cutting speed of 1000 mm/min.

PL

Cięcie szklanej płyty grzewczej o grubości 8 mm w kształcie koła za pomocą strumienia wody ze ścierniwem pod wysokim ciśnieniem w dwóch różnych rozmiarach prowadzi jest problematyczne ze względu na pękanie i powstawanie zadziorów na krawędziach. W rezultacie konieczne staje się wtórne szlifowanie, co nie tylko marnuje czas, ale również podnosi koszty. Ponadto proces ten zwiększa ilość wytwarzanego materiału odpadowego. Celem badań, których wyniki przedstawiono w niniejszym artykule, była optymalizacja procesu cięcia poprzez eksperymentalne określenie parametrów wpływających na jakość krawędzi szkła o grubości 8 mm, w szczególności po dostosowaniu ustawień maszyny CNC do cięcia strumieniem wodno-ściernym w celu poprawy okrągłości cięcia. Przeprowadzono szereg testów przy różnych ciśnieniach wody, natężeniach przepływu, typach dysz, średnicach otworów i ścierniwach granatowych. Wyniki wykazały, że najbardziej efektywne i wolne od wad warunki cięcia uzyskano przy ciśnieniu 2000 bar, przepływie ścierniwa 0,4 kg/m3, średnicy otworu w dyszy 0,76 mm, średnicy otworu kryzy 0,25 mm, materiale ściernym z granatu o rozmiarze 120 mesh i prędkości cięcia 1000 mm/min.

3

Cold forming of steel - selected processes, issues, and CAx

Horajski Piotr

Systemy Wspomagania w Inżynierii Produkcji

|

2024

|

Vol. 13, iss. 1

41--54

EN

This paper presents an analysis of the key challenges and irregularities associated with metal plastic deformation processes, with particular emphasis on phenomena such as springback, wrinkling, folding, cracking, microcracking, and burr formation. These undesirable effects can negatively impact the quality of final products and their mechanical properties, as well as the durability of tools used in processes such as bending, stamping, spinning, and cutting. The paper discusses the mechanisms leading to the formation of these defects, highlighting the role of process conditions, such as stress, processing speed, and tool geometry, which can cause technological issues. It also emphasizes the significance of tool wear, particularly in cutting processes, where abrasive, adhesive, and fatigue wear can lead to burr formation and deterioration in the quality of cut components. The study further explores methods to minimize these defects through process parameter optimization and proper tool design. Special attention is given to the use of numerical tools, such as the finite element method (FEM), which enables precise modeling of stress and strain distributions and the prediction of potential defect locations. Advanced simulations allow for improved prediction of issues like cracking, wrinkling, and springback, which ultimately enhances the quality of deformation processes and final products. The paper also highlights the need for further research in plastic deformation and the development of numerical models, particularly in the context of accounting for microstructural changes and residual stresses in materials.

PL

Niniejsza praca przedstawia analizę kluczowych wyzwań i nieprawidłowości związanych z procesami deformacji plastycznej metali, ze szczególnym uwzględnieniem takich zjawisk jak powrót sprężysty, marszczenie, fałdowanie, pękanie, mikropęknięcia oraz powstawanie gratu. Te niepożądane efekty mogą negatywnie wpływać na jakość finalnych produktów oraz ich właściwości mechaniczne, a także na trwałość narzędzi wykorzystywanych w procesach, takich jak gięcie, tłoczenie, wyoblanie czy cięcie. W pracy omówiono mechanizmy prowadzące do powstawania tych wad, zwracając uwagę na rolę warunków realizacji procesu i zjawisk fizycznych, takich jak naprężenia, prędkość obróbki oraz geometrię narzędzi, które mogą prowadzić do problemów technologicznych. Podkreślono również znaczenie zużycia narzędzi, w szczególności w kontekście procesów cięcia, gdzie zużycie cierne, adhezyjne oraz zmęczeniowe może prowadzić do powstawania gratu oraz pogorszenia jakości ciętych elementów. Analizowano także metody minimalizowania wspomnianych wad poprzez optymalizację parametrów procesowych i odpowiednie projektowanie narzędzi. Szczególną uwagę poświęcono wykorzystaniu narzędzi numerycznych, takich jak metoda elementów skończonych (MES), która pozwala na precyzyjne modelowanie rozkładów naprężeń, odkształceń oraz przewidywanie miejsc potencjalnych wad. Dzięki zaawansowanym symulacjom możliwe jest lepsze przewidywanie zjawisk takich jak pękanie, fałdowanie czy powrót sprężysty, co pozwala na poprawę jakości procesów deformacyjnych i produktów końcowych. Wskazano również na potrzebę dalszych badań w zakresie obróbki plastycznej oraz rozwoju modeli numerycznych, szczególnie w kontekście uwzględniania zmian mikrostrukturalnych i naprężeń resztkowych w materiałach.

4

Methods of Reducing Burrs in the Process of Cutting and Blanking Metal Materials

Bohdal Łukasz, Kułakowska Agnieszka, Tomkowski Robert, Ssemakula Hamzah Ssekiunga

Rocznik Ochrona Środowiska

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2024

|

Tom 26

629--637

EN

In metal cutting and blanking processes, one of the primary technological challenges is the formation of burrs on the surfaces of cut parts, especially in thin materials. Many companies face the issue of excessive waste due to burr formation after cutting. Understanding the causes of this defect is complex. This paper presents the current state of knowledge and the authors' research on reducing burr occurrence on cut surfaces. The conditions for achieving a high-quality cut edge were determined through numerical and experimental studies. With the increase of the rake angle in shear-slitting, the burr height decreases. When cutting with trimming, the cutting clearance value should be within hc = 1-3% of the material thickness. When blanking, the cutting clearance should be less than 10% of the thickness of the material being cut. The findings support selecting optimal process conditions to minimise waste after cutting.

5

An introduction to laser materials processing

Lima M. S. F., Siqueira R. H. M., Batalha G. F.

Journal of Achievements in Materials and Manufacturing Engineering

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2024

|

Vol. 126, nr 1

17--30

EN

Purpose: of the paper is to proceed with a short introduction and review of lasers for materials processing, showing that they have been used for marking, machining, treating, welding, and additive manufacturing in different areas, such as can-code bar printing and aeroplane manufacturing. Design/methodology/approach: The paper proceeded with a short review and introduced the laser processing of materials based on the authors' experience. Findings: The laser processing system revenues from cutting operations attained approximately 45% of the global market, followed by 20% for welding and brazing and 10% for marking and engraving. Research limitations/implications: Laser beam welding is the principal manufacturing technology for joining applications because of its low heat input, which leads to low distortions, high welding speeds, good control of the microstructure, and flexibility. Laser-induced breakdown spectroscopy (LIBS) of potentially dangerous substances (bio-agents, drugs, and nuclei), where a very small portion of the target is burned and analysed at a secure distance. Practical implications: Laser additive manufacturing is a growing area of interest in many industries and, together with surface processing, could be a major driving force for the laser market in the coming years. The paper briefly reviews the important characteristics of each laser–material processing technology for prospective users. Originality/value: The value of this introductory review is based on previous research and contributions carried out by the authors.

6

Technologie cięcia w produkcji kanałów wentylacyjnych z blach powlekanych

Michalski Dariusz, Kurp Piotr, Kroner Andrzej

Stal, Metale & Nowe Technologie

|

2023

|

nr 3-4

60--69

PL

W niniejszym artykule autorzy analizują technologie cięcia blach i taśm stalowych ocynkowanych wg PN-EN 10346:2015-09 [1] w gatunku DX51DZ275-M-A-C [2], o wydatku ocynku 275 g/m2. Wykorzystuje się je do produkcji różnego rodzaju kształtek wentylacyjnych prostokątnych i kanałów. Materiały o grubości w zakresie od 0,6 do 1,5 mm stosowane do produkcji muszą spełniać wymagania normy PN-89/H-92125.

EN

In this article, the authors analyse the technologies of cutting galvanized steel sheets and strips according to PN-EN 10346:2015-09 [1] in the grade DX51DZ275-M-A-C [2], with the galvanizing coating of 275 g/m2. They are used for the production of various types of rectangular ventilation fittings and ducts. Materials with a thickness in the range from 0.6 to 1.5 mm used for production must meet the requirements of the PN-89/H-92125 standard. The process of cutting, i.e. the loss of material consistency, consists in mechanical or thermal impact on the material until it is cut or burned through its entire thickness.

7

How do different types of river maintenance works affect the ichthyofauna of small European watercourses?

Brysiewicz Adam, Czerniejewski Przemysław, Sieczko Leszek

Ecological Chemistry and Engineering. S

|

2023

|

Vol. 30, nr 4

617--633

EN

Watercourses serve the needs of agriculture in certain sections and are subject to strong anthropopressure. When agriculture prevails in the catchment, it often has abundant vegetation, macrophytes in particular, and the bottom is covered by a substantial layer of silt. In order to ensure patency of flow and access to water, small watercourses are very often subject to river maintenance works. The aim of the study was to assess the impact of 3 types of works on the diversity of fish species and density of fish in the 1 and 2 year after the works at 21 sites located on 8 rivers in the European Central Plains Ecoregion. As a result of the works, especially in the 1 year after the works, significant changes were found in hydrochemical and hydrological parameters, especially with the increase in velocity and mean depth in watercourses. Additionally, habitat change contributed to differences in the composition of the ichthyofaunal. After 1 year, the diversity of fish species and fish population density increased or remained unchanged after dredging and removal of plants from the river channel, but they decreased after the removal of macrophytes from river banks. After year 2, a decrease in the diversity of fish species and density was observed, associated with re-infestation and siltation of the watercourses. Particularly in the case of dredging and removal of macrophytes from the river bank, maintenance works should not be done too frequently, because some species of natural value disappear.

8

Investigation on surface roughness and kerf analysis in abrasive water jet machining of silicon carbide

Hynes N.R.J., Asirvatham A.D., Sankaranarayanan R., Raja S., Benita B., Atchaya J.

Archives of Materials Science and Engineering

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2023

|

Vol. 120, nr 1

30--35

EN

Purpose: Machining silicon carbide (SiC) is challenging due to its brittle and maximum tensile nature. Lapping or laser beam are done with a high cost of manufacturing and low material removal rates. Water abrasive jet cutting is a promising candidate since the machining temperatures and processing force of ceramics are extremely low. Investigation into the abrasive water jet machining of silicon carbide is carried out in the present work. Design/methodology/approach: The variations in traverse speed while abrasive water jet cutting of silicon carbide and its effect on the surface roughness and kerf characteristics are studied. Silicon Carbide abrasive material is used as garnet consisting of 80 mesh. The surface roughness was calculated along with the depth of the cut made during the processing. Findings: The outcomes demonstrated that the traverse speed is more effective upon the surface roughness and is an important factor that damages the top kerf width and the kerf taper angle. Research limitations/implications: Based on the hardness and thickness of the SiC plate, the taper angle is high, and for a feed rate of 10 mm/min, the surface roughness is low. Less thickness of the SiC plate could have a lower taper angle than with high thickness. The erosive force is provided by abrasive material along with the jet stream. Practical implications: Water abrasive fine jet could effectively machinate silicon carbide ceramic material with a better surface finish accurately. Suitable surface roughness with higher productivity can be attained with medium traverse speed. Originality/value: The effect of process parameters on kerf taper angle and top kerf width in the abrasive water jet machining of silicon carbide is explored, considering surface roughness as an important output parameter.

9

The effect of air plasma cutting on the quality, structural transformations and changes in the chemical composition of structural steel

Górka Jacek

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 3

art. no. e215, 2023

EN

The article presents results of tests concerning the effect of technological parameters of the plasma arc cutting process (involving the use of air as plasma gas) on the quality of cut surfaces as well as on structural transformations and changes in the chemical composition of 14 mm-thick plates made of steel S235JR. The tests revealed that the adjustment of optimum parameters of the cutting process enabled the obtainment of cut surfaces representing quality class I in accordance with the ISO 9013 standard. Only the surfaces processed using the maximum cutting rates represented quality class II. The chemical composition analysis was performed using an ICXA 733 X-ray microanalyser (Jeol) equipped with an energy-dispersive spectrometer (EDS) and an ISIS 300 analytical system (OXFORD). The cut surfaces were observed and their characteristic areas were photographed using an X-ray microanalyser and the backscattered electrons (BSE) technique. The phase analysis was performed using a PHILIPS PW 1050 X’Change machine operated in the B–B (Bragg–Brentano) geometry. It was observed that the application of the air plasma cutting process led to the formation of an amorphous phase on the cut surface. The amorphous phase was characterised by a very high nitrogen content (of approximately 1.6%) and a hardness of 750 HV 0.2. The intense nitration resulted from the diffusion of nitrogen from the plasma gas. At the same time, the effect of air plasma arc gases on the liquid metal was responsible for the carburising of the cut surface (up to approximately 0.5%) and the burnout of alloying components (in accordance with the theory of the selective oxidation of chemical elements). The quality of the cut surfaces was primarily affected by the cutting rate. An increase in the cutting rate was accompanied by the deterioration of the geometric features of cut surfaces. In addition, higher cutting rates also translated into the significant reduction of the HAZ width and that of the size of the zone of chemical composition changes. The tests revealed that, in terms of the 14 mm-thick plates made of steel S235JR, the optimum cutting rates were restricted within the range of 600 mm/min to 1500 mm/min. The tests carried out made it possible to determine the influence of the active plasma gas (oxygen, nitrogen) both on changes in the chemical composition of the tested steel and on the quality of the cut surfaces obtained.

10

Hob wear prediction based on simulation of friction, heat fluxes, and cutting temperature

Hrytsay Ihor, Stupnytskyy Vadym

Archive of Mechanical Engineering

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2023

|

LXX, nr 2

271--286

EN

Based on comprehensive interrelated mathematical and graphical-analytical models, including 3D cut layers and simulation of contact, strain, force, and thermal processes during gear hobbing friction forces, heat fluxes, and temperature on the teeth of the hob surface are investigated. Various physical phenomena are responsible for their wear: friction on contact surfaces and thermal flow. These factors act independently of each other; therefore, the worn areas are localized in different active parts of the hob. Friction causes abrasive wear and heat fluxes result in heat softening of the tool. Intense heat fluxes due to significant friction, acting on areas of limited area, lead to temperatures exceeding the critical temperature on certain edges of the high-speed cutter. Simulation results enable identification of high-temperature areas on the working surface of cutting edges, where wear is caused by various reasons, and make it possible to select different methods of hardening these surfaces. To create protective coatings with maximum heat resistance, it is advisable to use laser technologies, electro spark alloying, or plasma spraying, and for coatings that provide reduction of friction on the surfaces – formation of diamond-containing layers with minimum adhesion properties and low friction coefficient on the corresponding surfaces.

11

Technologia oraz linie do cięcia poprzecznego i wzdłużnego blach

Trzepieciński Tomasz

Stal, Metale & Nowe Technologie

|

2022

|

nr 7-8

59--63

PL

W artykule przedstawiono przebieg procesu cięcia mechanicznego za pomocą dwóch krawędzi tnących oraz zarys technologii i funkcjonalność linii do cięcia wzdłużnego i poprzecznego blach.

EN

The article presents the process of mechanical cutting with two cutting edges as well as the outline of the technology and functionality of lines for sheet metal cross-cutting and slitting.

12

Analiza wybranych technologii cięcia blach powlekanych stosowanych do produkcji kanałów wentylacyjnych

Michalski Dariusz, Kurp Piotr, Kroner Andrzej

Stal, Metale & Nowe Technologie

|

2022

|

nr 5-6

80--87

PL

W niniejszym artykule autorzy analizują technologie cięcia blach i taśm stalowych ocynkowanych wg PN-EN 10346:2015-09 [1] w gatunku DX51DZ275-M-A-C [2], o wydatku ocynku 275 g/m2. Wykorzystuje się je do produkcji różnego rodzaju kształtek wentylacyjnych prostokątnych i kanałów. Materiały o grubości w zakresie od 0,6 do 1,5 mm stosowane do produkcji muszą spełniać wymagania normy PN- -89/H-92125. Proces cięcia, czyli utraty spójności materiału, polega na mechanicznym lub cieplnym oddziaływaniu na materiał do momentu jego przecięcia lub przepalenia na całej jego grubości.

EN

In this article, the authors analyse the technologies of cutting galvanized steel sheets and strips according to PN-EN 10346:2015-09 [1] in the grade DX51DZ275-M-A-C [2], with the galvanizing coating of 275 g/m2. They are used for the production of various types of rectangular ventilation fittings and ducts. Materials with a thickness in the range from 0.6 to 1.5 mm used for production must meet the requirements of the PN-89/H-92125 standard. The process of cutting, i.e. the loss of material consistency, consists in mechanical or thermal impact on the material until it is cut or burned through its entire thickness.

13

Niekonwencjonalne metody cięcia we współczesnych procesach wytwórczych

Styp-Rekowski Michał, Oborsky Ivan L., Polishchuk Oleg

Obróbka Metalu

|

2022

|

nr 3

54--59

PL

W artykule przedstawiono niekonwencjonalne metody przecinania materiałów konstrukcyjnych realizowanych we współczesnych procesach wytwarzania. Do tej grupy zaliczono przecinanie strugą wodną i wodno-ścierną a także przecinanie elektroerozyjne. Wskazano cechy pozytywne tych metod oraz kryteria jakimi powinno kierować się przy wyborze najlepszego sposobu przecinania.

EN

In this paper unconventional methods for cutting construction materials that are realized in modern manufacturing processes were presented. This includes cutting with water and abrasive-water jets and erosion treatment. It shall indicate their positive features and the criteria according to which the method should be selected.

14

Experimental evaluation of eccentric mechanism power loading of movable pressure plate in die-cutting press

Knysh Oleh, Rehei Ivan, Kandiak Nazar, Ternytskyi Serhij, Ivaskiv Bohdan

Acta Mechanica et Automatica

|

2022

|

Vol. 16, no. 3

266--273

EN

The paper reports experimental research on torques during cardboard cutting in the die-cutting press with eccentrics in the drive of the movable pressure plate. To conduct the research, an experimental bench with eccentrics in the drive of the die-cutting press is designed and manufactured. The manufactured experimental device for the research on cardboard blanks provides the possibility of getting dependencies of loadings at different parameters of the die-cutting process. The experimental approach envisages the use of the strain gauge measurement method and the wireless module for data collecting, as well as the software for its processing, for getting trustworthy results with minimum faults. The method gives an opportunity to study the torque values during the cardboard-cutting efforts on the drive shaft. The paper shows changes in the torque value on the drive shaft during the kinematic cycle with and without the use of cardboard blank. The angle of the drive shaft rotation during the cutting process was evaluated at selected values of the cardboard thickness. The relationship between the linear cutting efforts and the cardboard thickness, its fibre direction, cutting rule type and rotational speed of the drive shaft is elaborated. This kind of data is approximated by a logarithmic function (logarithmic curve), at R2 from 0.90 to 0.98. The thickness of the cardboard significantly influences the value of the linear cutting effort at all the studied parameters.

15

Technologia oraz linie do cięcia poprzecznego i wzdłużnego blach

Trzepieciński Tomasz

Stal, Metale & Nowe Technologie

|

2021

|

nr 1-2

52--57

PL

W artykule przedstawiono przebieg procesu cięcia mechanicznego za pomocą dwóch krawędzi tnących oraz zarys technologii i funkcjonalność linii do cięcia wzdłużnego i poprzecznego blach.

EN

The article presents the process of mechanical cutting with two cutting edges as well as the outline of the technology and functionality of lines for sheet metal cross-cutting and slitting.

16

Analiza wybranych technologii cięcia blach powlekanych stosowanych do produkcji kanałów wentylacyjnych

Michalski Dariusz, Kurp Piotr, Kroner Andrzej

Stal, Metale & Nowe Technologie

|

2021

|

nr 11-12

46--56

PL

W niniejszym artykule autorzy analizują technologie cięcia blach i taśm stalowych ocynkowanych wg PN-EN 10346:2015-09 [1] w gatunku DX51DZ275-M-A-C [2], o wydatku ocynku 275 g/m2. Wykorzystuje się je do produkcji różnego rodzaju kształtek wentylacyjnych prostokątnych i kanałów. Materiały o grubości w zakresie od 0,6 do 1,5 mm stosowane do produkcji muszą spełniać wymagania normy PN- -89/H-92125. Proces cięcia, czyli utraty spójności materiału, polega na mechanicznym lub cieplnym oddziaływaniu na materiał do momentu jego przecięcia lub przepalenia na całej jego grubości.

EN

In this article, the authors analyse the technologies of cutting galvanized steel sheets and strips according to PN-EN 10346:2015-09 [1] in the grade DX51DZ275-M-A-C [2], with the galvanizing coating of 275 g/m2. They are used for the production of various types of rectangular ventilation fittings and ducts. Materials with a thickness in the range from 0.6 to 1.5 mm used for production must meet the requirements of the PN-89/H-92125 standard. The process of cutting, i.e. the loss of material consistency, consists in mechanical or thermal impact on the material until it is cut or burned through its entire thickness.

17

Neuromodel of the "Crusher mill" Mechatronic Complex

Kalinchyk Vasyl, Meita Olexandr, Pobigaylo Vitalii, Kalinchyk Vitalii, Filyanin Danylo

Rocznik Ochrona Środowiska

|

2021

|

Tom 23

470--483

EN

To create a mechatron model of vacuum tube vibration system for rock cutting by flat auger tools based on physical and mechanical properties of processed array and kinematic characteristics of the instrument. The analytical model of the fracture process of rock cutting by tool vibration with considering of plastic properties of the massif were developed. The main technological parameters of massif vibrating cutting with normal variations were modeled: dependences of normal and tangential pressure in the zone of working body interaction with the medium, normal and shear stresses in the zone of destruction, rock characteristics of the medium, vibration parameters dependences on the characteristics of mechatronic system geometry of the contact area of flat incisors treated with medium. The choice of the computational model of the vibration rock cutting with the normal to the direction of movement of the working body fluctuations with considering arising from processes at once or disorders: the occurrence of compressive and tensile stresses were backgrounded. Main stages and interconnection options in the simulation of vibration cutting were established. Scientific novelty lies in the development of a method of analysis of contact interaction of roller working body molding machine with an array taking into account the changes in the stabilization process of physical and mechanical properties of the treated medium, the aim of which is to predict the required voltage and depth of the formed layer. The theoretical basis of rock cutting by flat auger tool taking into account the normal component of the vibration with respect to the movement direction allowing for the deformation of the rock mass and the contact interaction with the working body were established, that allows to improve the technology of drilling wells by reducing the power consumption of the cutting process. The results enable us to determine the parameters of power and kinematic conditions for the occurrence of the vibration cutting.

18

Wyniki badań własności mechanicznych skał w aspekcie metody urabiania

Bołoz Łukasz

Przegląd Górniczy

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2021

|

T. 77, nr 1-3

38--47

PL

W artykule przedstawiono tematykę związaną z często pomijanym wpływem kierunku urabiania na generowane opory urabiania skał. Na etapie prac związanych z rozpoznaniem złoża lub doborem sposobu eksploatacji przeprowadzane są badania określające własności mechaniczne calizny. Najczęściej przeprowadza się badania wytrzymałości na jednoosiowe ściskanie oraz czasami urabialności skał. Bardzo często wyniki tych badań silnie zależą od kierunku ich realizacji. Ponadto w zależności od sposobu urabiania (frezowanie, struganie, wiercenie) oraz miejsca pobierania próbek (ocios ściany, czoło lub ocios chodnika) kierunek skrawania zazwyczaj nie jest zgodny z kierunkiem realizacji badań. W artykule zwrócono uwagę na występujące w praktyce kierunki skrawania oraz przedstawiono, opracowane w tym celu dla górnictwa podziemnego, zalecenia dotyczące kierunku prowadzenia badań w celu prawidłowego określenia własności calizny. Zaprezentowano również autorskie wyniki badań węgla kamiennego, soli kamiennej oraz piaskowców, łupków i dolomitów, przeprowadzonych w trzech prostopadłych kierunkach. Ponadto dokonano przeglądu literatury w tym aspekcie, prezentując wybrane badania. Wyniki badań potwierdzają występowanie kilkukrotnych, czasami prawie pięciokrotnych, różnic wartości własności mechanicznych w zależności od kierunku obciążania. Wiedza dotycząca planowanego kierunku skrawania oraz kierunku realizacji badań jest warunkiem koniecznym prawidłowej interpretacji wyników i doboru techniki urabiania, rodzaju narzędzi, parametrów procesu oraz spodziewanej efektywności i energochłonności.

EN

The paper is concerned with the influence of cutting direction on rock cutting resistance, which is a frequently neglected issue. Investigations into the mechanical properties of unmined rock are carried out at the stage of works involving deposit identification or mining method selection. The most frequently performed tests include uniaxial compressive strength and, sometimes, mineability of the unmined rock. The results of these tests are strongly correlated with the direction in which they have been carried out. Additionally, depending on the method of mining (cutting, planning, drilling) and the site of sampling (sidewall, face), the direction of cutting is usually inconsistent with the direction of testing. In the article, the author has drawn attention to the commonly applied directions of cutting and presented recommendations on the direction of testing to be followed in underground mining plants in order to properly determine the unmined rock properties. The results of author’s research into hard coal mine, rock salt and sandstones, shales and dolomites, conducted in three perpendicular directions have also been quoted. Furthermore, the subject literature in this field has been reviewed and selected investigations presented. The research results confirm that depending on the cutting direction, there may be considerable, even fivefold differences in the value of mechanical properties. Knowing the planned cutting direction and the direction of testing is a necessary condition for interpreting the results in a proper way, choosing a suitable mining technique, the type of tools and process parameters, as well as achieving the projected efficiency and energy consumption.

19

Wpływ głównych parametrów wysokociśnieniowej strugi wodno-ściernej na jakość powierzchni przeciętej stali HARDOX 500

Perec Andrzej

Obróbka Metalu

|

2021

|

nr 2

34--39

PL

Przedstawiono wyniki badań wpływu najważniejszych parametrów procesu przecinania wysokociśnieniową strugą wodno-ścierną stali Hardox na chropowatość powstałej powierzchni. W celu określenia najkorzystniejszych parametrów kontrolnych procesu skrawania stworzono matematyczno-statystyczny model procesu cięcia wykorzystując metodę powierzchni odpowiedzi (RSM). Wybrano równanie wielomianowe drugiego stopnia i na jego podstawie stworzono model obróbki, umożliwiający znalezienie optymalnych parametrów kontrolnych oraz predykcję wartości chropowatości powierzchni przeciętej.

EN

The results of investigations of the influence of the most important parameters of the cutting process of highpressure water jet cutting of Hardox steel on the roughness of the resulting surface are presented. A mathematical-statistical model of the cutting process based on the response surface method (RSM) was created to determine the most favorable control parameters of the cutting process. A second-degree polynomial equation was chosen and a machining model was created based on this equation to find the optimal control parameters and predict the value of the cut surface roughness.

20

Tribologia obróbki skrawaniem wspomaganej ciekłym dwutlenkiem węgla ze smarem stałym

Jemielniak Krzysztof

Mechanik

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2021

|

R. 94, nr 7

20

PL

Współczesną tendencją w obróbce skrawaniem metali jest dążenie do eliminacji szkodliwego dla środowiska chłodzenia zalewowego. Jednym ze stosowanych rozwiązań jest chłodzenie kriogeniczne ciekłym dwutlenkiem węgla (LCO2). Efektywność takiego chłodzenia można podnieść dzięki połączeniu go ze smarem stałym.