Papers by Keyword: Cutting

Abstract: In this research work, we aim to evaluate the cutting resistance and deformation of a laminated nylon film subjected to a 42^o wedged indentation. One of the problems occurred in the wedge indentation process is the unstable separation and quality of the sheared profile of the worksheet. In order to reveal the effect of cutting parameters on the cutting features, the indentation experiment of 0.16 mm thickness of Polyamide-6/ Polyethylene nylon film (PA6/PE) was conducted; the cutting line force was gotten using a recording unit; the bent-up angle and sheared profile of the worksheet were observed using a high-speed camera. From the experiment results, it was found that the cutting direction was an important factor affected to the bent-up angle and cutting load response of the nylon film. Also, the effect of cutting direction (PA6-PE and PE-PA6) of the nylon film was numerically investigated.

Abstract: The paper analyzes the structure of coal beds. It is noted that coal beds belong to laminar massifs with characteristic oriented structure and pronounced anisotropy of strength properties, and include rock layers and consolidated hard inclusions. The quality criteria of the coal loosening process are highlighted. A selective method of separating coal from a massif by cutting along weakened surfaces is proposed as an alternative to the existing combine technology with continuous cutting of a massif from the surface.

Abstract: This paper investigates the effect of the laser cutting parameters on the heat-affected zone, and on the boundary layer of stainless steel processing. A new analytical resolution based on the boundary layer theory is used to deduce the interaction effects of the cutting parameters on the above zones. The results revealed that, the laminar nitrogen assist gas has a negligible effect on the HAZ depth but it has a remarkable effect on the molten boundary layer. It is also noticed that the pressure gradient remains very small compared to the interface shearing and the conductive heat losses from the cutting zone towards the substrate is dominant compared to the convective heat losses towards the gas.

Abstract: The paper proposes a mathematical model of the formation of a deep-hole cut when boring it; substantiates that the cut is manifested as the technological heredity of the errors of the workpiece; confirms theoretical positions by using the method of computer simulation of the process of shaping during the finishing boring of the deep holes of hydraulic-cylinder barrels made of various steels; and introduces design and technological methods for minimizing hole errors.

Abstract: In this paper, based on the technical theory developed by the article contributors and the theory designed for twisting of a composite laminated rod of any cross section, a computer program for numerical stress-strain analysis of laminated composite blades in the centrifugal forces field is presented. The naturally twisted laminated composite blade is considered to be under the combined action of the tensile stresses, bending and twisting moments or under the influence of centrifugal forces. In the program, the technological problem of blade unfolding into petals is solved. These petals lie in planes which are parallel to the rod axis and appear due to the varying cross-section along the length of the blade. The investigated blade is represented with eight sections. The results of research on stress-strain behaviour of boron aluminium laminated compressor blades which operate in the fields of centrifugal forces are analysed.

Abstract: During the dry machining operation, the cutting tool is constantly subjected to extreme conditions in terms of thermal and mechanical stresses at the tool-chip interface. Indeed, the high temperature and the large plastic deformation affect and particularly accelerate the degradation of the state of the coating of the cutting tool. Thus, it becomes essential to predict the initiation and propagation of a crack in a coated tool. This makes it possible to optimize the cutting and loading conditions in order to improve the efficiency of the coating used and consequently the service life of the cutting tools.In this work, a finite element calculation code "ABAQUS / STANDARD" was used to study and analyze the cracking of a diamond-coated cutting tool. In this sense, we proposed to combine two methods often used to study the discontinuity at the tool-chip and coating-substrate interface. These are respectively the extended finite element method (XFEM) method and the cohesive element method. In addition, a parametric study on the impact of beak radius on cracking was performed to optimize this parameter.

Abstract: In the article the model for forecasting of thermal processes arising during processing of bevel gears is presented. The kinematics of cutting is modeled due to the analytical model. Chipping is modeled using the finite element method. The experiment is based on the method of infrared photography of the cutting process. In the process of carrying out a numerical experiment, the graphs of the heat fields for the tool, the workpiece gear and chips were obtained, and an array of data on their change during the cutting process was achieved. The simulation results showed that the maximum temperatures and heat flows in the tool depend significantly on the choice of the rake and clearance angels of the cutting.

Abstract: A thick glass plate was cut by using hot wire. Crack growing was stopped when wire temperature was low. Ligament length decreased with increase in temperature of hot wire and full-cutting was achieved at the temperature of 650°C. The center region in the thickness direction seemed to propagate earlier compared to surfaces regions when the crack propagation was stopped. Finite element thermal stress analysis was carried out. According to distribution of thermal stress inside a glass plate, higher stress was generated in the bottom region at the beginning of the process but occurred in the center region in the later stage as matching with the experimental result.

Abstract: In order to clarify the effectiveness of the multi-layer AlCrWN/AlCrWSiN-coated cemented carbide tool, the wear progress was investigated in cutting hardened sintered steel using three types of coated tool. Namely, Tool I had the dual-layer (Al60,Cr25,W15)(C,N)/(Al53,Cr23,W14,Si10)(C,N)-coating film, Tool II had the multi-layer (Al60,Cr25,W15)(C,N)/(Al53,Cr23,W14,Si10)(C,N)-coating film and Tool III had the multi-layer (Al60,Cr25,W15)N/(Al53,Cr23,W14,Si10)N-coating film. The following results were obtained: (1) The main tool failure of the three types of coated tools were the flank wear within the maximum value of the flank wear width of 0.2 mm. (2) The critical scratch load of the three types of coated tools was 130 N or more. (3) The micro-hardness of Tool III 3000 HV0.25N was the highest among the three types of coated tools. (4) The mean value of the friction coefficient of the (Al53,Cr23,W14,Si10)N coating film, 0.21, was approximately half that of the (Al53,Cr23,W14,Si10)(C,N) coating film, 0.41. (5) In the case of the higher cutting speed, the wear progress of the multi-layer coating system was slower than that of the dual-layer coating system. (6) In the case of the cutting hardened sintered steel using the multi-layer coated tool, the wear progress of the Type III coated tool was slower than that of the Type II coated tool.

Abstract: In turning hardened steel, polycrystalline cubic boron nitride (cBN) compacts are widely used, due to their high hardness and high thermal conductivity. However, in milling hardened steel, fracture of cBN cutting tools readily occurs because they have poor fracture toughness. Therefore, coated cemented carbide tools, which have good fracture toughness and wear resistance, are generally and widely used. In this study, hardened steel (ASTM D2, JIS SKD11, 60HRC) was milled with three physical vapor deposition coated cemented carbide end mill cutters in order to determine effective tool materials for milling hardened steel. The coating films used were two types of aluminum/chromium/tungsten/silicon-based-coating films and (Ti,Al)N-coating film. The two types of aluminum/chromium/tungsten/silicon-based-coating films are a new type of coating film, and the Type I and Type II coating film was a two-layered and multi-layered structure, respectively. The following results were obtained: (1) In milling hardened steel at a cutting speed of 2.5 m/s, Type II coating film was the best coating material among the three types of coated film. Type I coating film was superior to (Ti,Al)N-coating film. (2) The critical scratch load of both Type I and Type II of over 130 N became larger than that of the (Ti,Al)N-coating film of 65 N. (3) The multi-layered structure is expected to improve the tool life.