Papers by Keyword: Cutting Zone

Abstract: In the paper the detailed structural changes in the cutting zone were determined using metallography. Accurate determination of parameters such as shear angle, slip angle, chip thickness, cutting ratio, chip separation point, etc. required metallographic analysis on a relatively complex sampling of the cutting area. We performed the analysis on an orthogonal cutting. We achieved orthogonal cutting by turning a thin-walled Inconel 718 and C45 alloy tubes and setting the lath bit cutting edge perpendicular to the tube axis. In real state, the shapes in the cutting zone are more complicated therefore the chip thickness was determined using quantitative metallography from the equality of areas and the resulting point of transition between the chip and the machined surface. The shear angle starts from this point and is a tangent to the cutting edge, the direction of which was determined using the Thales circle. The distance between this point and the machined surface which represents a layer which is not separated from the machined material but is planar deformed was determined too. The depth of the deformed layer and the value of deformation on the machined surface was determined by quantitative metallography. A much simpler numerical simulation was performed with the same parameters using Deform 2D/3D software package. Numerical simulation could not fully replace metallographic analysis, but to some extent numerical simulation can be used instead of metallographic analysis.

Abstract: Finite element modelling (FEM) of machining is a widely applied way to get information about the phenomena occurring during the cutting process. This paper discusses experimental work and FEM analysis to investigate the mechanism of CK45 (1.0503) carbon steel chip formation during orthogonal turning process. Local strain in cutting zone is estimated by measurement of deformation of metallographic cut using stereological evaluation of the gain boundary orientation. Estimated local strain in cutting zone was compared to deformation analysis for orthogonal cutting was made, based on simulation results in numerical modelling software DEFORM 2D. Stress, temperature, tool wear is also discussed in the last part of this paper.

Abstract: Local plastic deformation in cutting zone during turning is affected by technological conditions of the processes. Therefore it is needful to know detail structure changes of plastic deformed material during machining. It is localised, asymmetric deformation which operates at very large strains and exceptionally high strain rates. Three areas of intensive local plastic deformation in cutting zone were observed: the primary area of plastic deformation in shear plane, the secondary area of plastic deformation caused by friction of chip to tool face and the tertiary area of plastic deformation caused by friction of tool to machined surface. Local strain in these three areas was estimated by measurement of deformation of grains on metallographic cut. The effect of grains boundaries self-orientation caused by grains deformation was evaluated using stereology. But the orientation is not the same as deformation and so a correlation between the grain deformation and grain orientation was used. The turning piece was made of CK45 (1.0503) carbon steel. The specimen of cutting zone was obtained by using internal stress method.

Abstract: The The basic hypothesis of this article focuses on the study of accompanying phenomenas in the cutting zone of the stainless steels, with regard to the elimination of occurrence of poor-quality holes when drilling into new austenitic ELC (Extra Low Carbon) stainless steels. The problem of drilling holes with diameter D=1 to 9 mm resides in the fact that 20 to 28 % of these holes do not comply with prescribed requested requirements. The result of the deformation is very often the unforeseen destruction of the cutting tools; therefore their operational tool life is reduced. This article presents the results of experiments focusing on the study of the plastic deformation of the chips, at drilling with diameter d=5 mm when drilling into a new austenitic ELC stainless steels. This study also includes an analysis of accompanying phenomena in the cutting zone by measuring some selected parameters. The results of the experiments were compared with Cr18Ni8 steel and then verified when drilling holes into specific products.

Abstract: In the area of tribology, surface roughness has become one of the most important factors that contributed to the evaluation of part quality during machining operation. In order to understand the behavior of cryogenic cooling assistance in machining Inconel 718, this paper aims to provide better understanding of tribological characterization of liquid nitrogen near the cutting zone of this material in milling process. Experiments were performed using physical vapor deposition (PVD) - coated carbide inserts under cryogenic and dry cutting condition. The cryogenic results of the cutting temperature, cutting forces and surface roughness of the ball nose cutting tool have been compared with those of dry machining. Finally, experimental results proved that cryogenic implementation can decrease the amount of heat transferred to the tool up to almost 70% and improve the surface roughness to a maximum of 31% when compared with dry machining.

Abstract: This paper presents the conclusions of machinability tests on a Cast Iron GTW 35-04. The content of this article also focuses on the analysis of selected basic indicators of steel machinability: quality of the processed surface. The results of the article are conclusions for working theory and practice for drillng of cast iron. Based on the cutting tests, cutting speeds of 50 to 100 m/min, feed rate of 0.1 to 1.0 mm and screw drill carbide monolite.

Abstract: The basic hypothesis of the article focuses on the ploughing effect from the cutting process during the course of making holes by drilling into austenitic stainless steel X5Cr18Ni9. The problem with drilling holes with a diameter of D_w=3 through 10 mm. The article presents the results from experiments where stainless steel X5Cr18Ni9 was drilled. Based on the cutting tests, cutting speeds of 40 to 60 m/min, feed rate of 0.04 to 1.2 mm and screw drill carbide monolite.

Abstract: This paper presents the conclusions of machinability tests on a XCr18Ni8 stainless steel. The content of this article also focuses on the analysis of selected basic indicators of steel machinability: quality of the processed surface. The results of the article are conclusions for working theory and practice for drillng of austenitic stainless steels. Based on the cutting tests, cutting speeds of 40 to 60 m/min, feed rate of 0.04 to 1.2 mm and screw drill carbide monolite.

Abstract: Precise and reliable information on the machinability of a material before it enters the machining process is a necessity, and hypotheses must be tested through verification of actual methods. This article presents conclusions of machinability tests on a new austenitic stainless steels X2Cr12Ni12MoTiN and describes appropriate parameters for the cutting zone during the process of turning. The content of this article also focuses on the analysis of selected basic indicators of steel machinability: quality of the processed surface. The results of the article are conclusions for working theory and practice for turning of austenitic stainless steels. Based on the cutting tests, cutting speeds of 80 to 200 m/min, feed rate of 0.05 to 0.2 mm and solid carbide insert WNMG 080404-NF.

Abstract: The cutting zone temperature is the basic cutting process physical parameter, how to obtain it accurately is a problem over the years. In the paper, a method combined the artificial thermocouple method with thermal conduction reverse seeking method was proposed. The thermocouple can track the temperature history curve of the tool measured point. Then the tool and cutting process heat conduction models were built up in the ANSYS and AdvantEdge FEM respectively. According to the simulation results, the corresponding relationship between the rake face temperature and the measured point temperature and the shear slip face temperature can be solved. So the first and second deformation zone average temperature was obtained. Shown as the research results, the method proposed in the paper can obtain the small cutting zone temperature effectively. It provides technical support for the study of cutting process deformation and friction behavior.