scholarly journals A Critical Reanalysis of Uncontrollable Washboarding Phenomenon in Metal Band Sawing

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4472
Author(s):  
Kazimierz A. Orlowski ◽  
Michal Dobrzynski ◽  
Grzegorz Gajowiec ◽  
Marcin Lackowski ◽  
Tomasz Ochrymiuk
Keyword(s):  
Outer Layer ◽  
High Hardness ◽  
Cutting Process ◽  
Processed Material ◽  
Material Texture ◽  
Core Hardness ◽  
Wave Regeneration ◽  
Cutting Processes ◽  
Band Saw ◽  
Horizontal Band

The article analyzes the cutting process of hard bars. Investigations conducted in industrial conditions demonstrated the presence of surface errors in the machined workpieces in the form of washboard patterns. The purpose of this study was to analyze the results of cutting on band sawing machines with different band saw blades. The cutting processes were conducted on three different horizontal band sawing machine types. Analyzed material was an alloy steel Ø40 mm rod with a hardened surface covered with a thin layer of chromium. The hardness of the outer layer was 547 HV with a core hardness of 180 HV. The surface topography measurements of the processed workpieces were carried out with the 3D Optical Profiler, which supplied information on the irregularities of the processed material texture. In each of the analyzed cases, a corrugated surface was obtained after sawing, which is the effect of the occurrence of the washboarding phenomenon, despite the fact that the teeth of each band saw had variable pitches. The washboarding phenomenon when cutting rods with hard surfaces is caused by the phenomenon of wave regeneration. Despite the use of variable pitch saw blades, the cutting process results in rippling of the sawn surface, which is caused by the high hardness of the outer layer of the workpiece, as well as by the type of tool with spring setting of teeth.

Research of machining forces and technological features of cast PA6, POM C and UHMW-PE HD 1000

2010 ◽  
Vol 1 (1) ◽  
pp. 136-143
Author(s):  
Robert Keresztes ◽  
Gabor Kalacska
Keyword(s):  
Injection Molding ◽  
Cutting Force ◽  
Mechanical Engineering ◽  
Cutting Process ◽  
Engineering Practice ◽  
Serial Production ◽  
Machining Forces ◽  
Engineering Plastics ◽  
Machine Elements ◽  
Cutting Processes

Nowadays parts made of up-to-date engineering plastics are used more and morein mechanical engineering practice. These machine-elements are produced most frequentlyby injection molding or by one cutting process. The injection molding technology are usedgenerally for great number of pieces, in case of serial production while cutting processes arepreferred to piece (unit) or smaller number production.We used lathe and measured the main- and feeding-directional cutting force at differentengineering polymers (cast PA6, POM C and UHMW PE HD 1000). The analysis made canbe well used in practice.

scholarly journals Residual Stresses Distribution Posterior to Welding and Cutting Processes

2021 ◽  
Author(s):  
Asma Manai
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
Weld Seam ◽  
Considerable Change ◽  
Cutting Process ◽  
Local Material ◽  
Weld Residual Stress ◽  
Exact Size ◽  
Cutting Processes ◽  
Welding Processes

Welding is a joining process that leads to considerable change in the local material and the formation of welding residual stresses (RS). Welding residual stresses can be compressive (beneficial for the fatigue life) or tensile (harmful for the fatigue life). In this chapter, a probabilistic analysis of residual stresses distribution posterior to welding processes is carried out. Several researchers stated that the type of the introduced stresses either compressive or tensile depends on several factors. Some of these factors are listed in this chapter. Welding of mega-structures is carried out in the workshops, then a cutting process takes place to construct the exact size of the structural components. This cutting process has a significant effect on the weld residual stresses re-distribution. A study of the re-distribution of the weld residual stress after cutting was performed. It was found that independent of the weld seam length, the residual stresses re-distributed up to 60 % of the weld seam length.

Effect of Large Cross-Section Oxygen-Propane Flame Cutting on Microstructure in Heat-Affected Zone

2013 ◽  
Vol 274 ◽  
pp. 249-252
Author(s):  
Zhi Xin Wang ◽  
Yong Kui Han ◽  
Yong Qiu Chen
Keyword(s):  
Cross Section ◽  
Heat Affected Zone ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Pressure Vessels ◽  
Manufacturing Industries ◽  
Cutting Process ◽  
Pure Oxygen ◽  
Cutting Processes ◽  
34Crnimo6 Steel

Many metal-manufacturing industries include oxyfuel gas cutting among their manufacturing processes because cutting was often used in metal-cutting processes, specifically in the large castings and forgings and the fabrication of pressure vessels. The oxyfuel gas cutting process uses controlled chemical reactions to remove preheated metal by rapid oxidation in a stream of pure oxygen. Previous research has demonstrated microstructure in heat-affected zone varied depending on the gas used for the combustion as well as the cutting speed (Vc) used during the process. In this research, 34CrNiMo6 steel of 900 mm in thickness and 45 carbon steel of 450 mm in thickness were cut using an oxygen-propane flame cutting process. Then, macroscopic morphology and microstructure test were done to analyze the influence of the thickness of cutting cross-section. The results showed, in general, the width of heat-affected zone increased with the thickness of cutting cross-section. Also, it was demonstrated that heat-affected zone in the bottom and top section was wider than others.

Optimization of Laser Beam Cutting Process Parameters of Austenitic Materials

2015 ◽  
Vol 1111 ◽  
pp. 235-239 ◽  
Author(s):  
Sanja Petronić ◽  
Biljana Grujic ◽  
Dubravka Milovanovic ◽  
Radomir Jovicic
Keyword(s):  
Process Parameters ◽  
Laser Cutting ◽  
Elevated Pressure ◽  
Cutting Process ◽  
High Mechanical Strength ◽  
Complex Shapes ◽  
Manufactured Products ◽  
Modern Manufacturing ◽  
Design Requirements ◽  
Cutting Processes

Austenitic materials have high demand in modern manufacturing industries due to their improved technological characteristics such as high mechanical strength and hardness, corrosion resistance, heat resistance and wear resistance. Some applications of austenitic materials include elevated pressure and temperature, and require stringent design requirements and close tolerances in manufactured products. Laser cutting is one of the non-conventional cutting processes, used to obtain complex shapes and geometries. In this paper, laser cutting was performed on austenitic material. The laser cutting process parameters are varied with the aim to obtain the optimal process parameters. The geometric and metallurgical characteristics of the cut parts are investigated and compared to the conventional cutting methods of austenitic materials.

scholarly journals Modelling of Guillotine Cutting of a Cold-Rolled Steel Sheet

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2954 ◽  
Author(s):  
Jarosław Kaczmarczyk
Keyword(s):  
Steel Sheet ◽  
Cutting Process ◽  
Experimental Investigations ◽  
Rolled Steel ◽  
The Finite Element Method ◽  
Cold Rolled Steel ◽  
Cold Rolled ◽  
Cutting Processes ◽  
Professional Tool ◽  
Good Agreement

In this paper, the modelling of a cutting process of a cold-rolled steel sheet using a symmetrical cutting tool is presented. The fast-changing nonlinear dynamic cutting process was elaborated by means of the finite element method and the computer system LS-DYNA. Experimental investigations using scanning electron microscopy were performed and the results are presented in this work. The numerical results were compared with experimental ones. The comparison shows a good agreement between the results obtained by means of numerical modelling and those received from experimental investigations. The numerical simulations of the cutting process and the experimental investigations aimed to understand the mechanism of the cutting process. They serve as a highly professional tool for carrying out research investigating the behavior of complex nonlinear fast-changing dynamical cutting processes in the future.

Soil Cutting Processes: The Cutting of Water Saturated Sand

2011 ◽  
Author(s):  
Sape A. Miedema
Keyword(s):  
Pore Water ◽  
Cutting Forces ◽  
Water Vapor Pressure ◽  
Cutting Process ◽  
Shear Stresses ◽  
Saturated Sand ◽  
Pore Water Pressures ◽  
Offshore Industry ◽  
Cutting Processes ◽  
Water Saturated

The cutting process in water saturated sand has been the subject of research in the dredging industry for decades already. The Dutch dredging industry started this research in the sixties, resulting in a number of models in the seventies and eighties (van Leussen & van Os (1987) and Miedema (1987 and later). The application of the theory in the offshore industry is rare, although Palmer (1999) used it. In the last decades trenching has been a practice where these theories can be applied and with the tendencies of working in deeper water and in arctic conditions it is useful to try to combine the knowledge from the dredging and the offshore industry regarding cutting processes. The cutting process in water saturated sand is dominated by the phenomenon of dilatancy. Due to shear stresses, the porosity of the sand increases, resulting in an absolute decrease of the pore water pressures. Since the soil stresses are a constant, and equal to the sum of the grain stresses and the pore water stresses, this implies that the grain stresses increase with decreasing pore water stresses. This results in much higher cutting forces. The decrease of the pore water stresses is limited by the water vapor pressure and so are the cutting forces. At shallow waters, the pore water may start to cavitate if the strain rates are high enough, but at very deep water this will probably not occur. In this paper the basics of the cutting theory are explained. This cutting theory however requires a lot of finite element calculations in order to determine the pore water pressures. The paper gives simplification that allows the user to apply the theory with the help of pre-calculated coefficients.

Cutting Dynamics Identification by Dynamic Data System (DDS) Modeling Approach

1985 ◽  
Vol 107 (2) ◽  
pp. 91-94 ◽  
Author(s):  
T. Y. Ahn ◽  
K. F. Eman ◽  
S. M. Wu
Keyword(s):  
Transfer Functions ◽  
Moving Average ◽  
Analytical Form ◽  
Data System ◽  
Cutting Process ◽  
Autoregressive Moving Average ◽  
Multivariate System ◽  
Dynamic Data ◽  
Dynamic Cutting Force ◽  
Cutting Processes

The dynamics of the cutting process have been conventionally characterized in terms of the Dynamic Cutting Force Coefficients (DCFC) which represent its transfer characteristics at discrete frequencies. However, this approach fails to obtain the transfer function of the process in closed analytical form. Anticipating the stochastic nature of the cutting process and the double modulation principle, a two-input one-output multivariate system was postulated for the dynamic cutting process identification model. The Dynamic Data System (DDS) methodology was used to formulate and characterize the dynamic cutting process using Modified Autoregressive Moving Average Vector (MARMAV) models. Subsequently, transfer functions of the inner and outer modulation dynamics of the cutting processes were obtained from the identified models.

Characterization of Brittle Phase in Magnesium Based Materials Prepared by Powder Metallurgy

2018 ◽  
Vol 784 ◽  
pp. 61-66
Author(s):  
Michaela Krystýnová ◽  
Pavel Doležal ◽  
Stanislava Fintová ◽  
Josef Zapletal ◽  
Tomas Marada ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Powder Mixture ◽  
Intermetallic Phase ◽  
High Hardness ◽  
Laves Phases ◽  
Pressing Method ◽  
X Ray ◽  
Processed Material ◽  
Brittle Phase ◽  
Point Bend

Magnesium-zinc based materials are characteristic with the creation of intermetallic phases, strongly influencing material mechanical properties. Mg-Zn powder mixture (10 % wt. Zn) was processed by the hot pressing method under 500 MPa at 300 °C. Microstructure of the prepared material was analyzed in terms of light optical microscopy and scanning electron microscopy. Chemical and phase composition of the processed material were analyzed by energy-dispersive X-ray spectroscopy and X-ray powder diffraction, respectively. Microhardness testing was adopted to characterize created structure mechanical properties on the microscopic level. Depending on the Mg-Zn powder mixture local chemical composition, the structural and chemical analysis of the processed material revealed that it consisted of magnesium and zinc rich areas, and MgZn2 intermetallic phase. The MgZn2 intermetallic phase belongs to the so-called Laves phases group with the general formula AB2. Laves phases are characteristic with high hardness and the related high brittleness. Their presence in the material usually results in deterioration of mechanical properties such as strength and toughness. The microhardness of magnesium and zinc rich areas in the processed material was 58±1 HV 0.025 and 47 ±1 HV 0.025, respectively, while the value of the microhardness for MgZn2 intermetallic phase was 323±12 HV 0.025. Different behavior and mechanical properties of the present phases was observed on the fracture surfaces of specimens broken during the 3-point bend test. While brittle fracture was a characteristic feature for MgZn2 intermetallic phase, the rest of the material exhibited more ductile fracture behavior with characteristic transgranular failure.

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