Split Cutter Method for Contact Stresses Research over Flank Surface of a Cutter

2017 ◽  
Vol 743 ◽  
pp. 258-263 ◽  
Author(s):  
Victor Kozlov ◽  
Jia Yu Zhang ◽  
Jian Cui ◽  
Maria Bogolyubova

The paper presents a method for of contact load (stress) research over a flank land of a cutter by a “split cutter” (sectional cutter) method which is more preferable in cutting steels and durable materials in industrial cutting mode. The research of contact stresses distribution over surfaces of a cutter must be carried out on the special rigid four-component dynamometer for the “split cutter” with inspection of total components of cutting force Pz and Py. However, the investigation of contact loads distribution over the flank land faces the problem due to elastic deformation of measuring elements and penetration of work material into a slit between the two parts of the “split cutter”. The research of contact stresses distribution over a face of a cutter should be carried out on a lathe with horizontal radial feed, while the research of contact stresses distribution over a flank land should be done on a horizontal-milling machine with vertical radial feed of a table. The distributions of contact stresses over the flank land of the cutter in free orthogonal turning of a disk made from ductile brass (63Cu-37Zn), brittle brass (57Cu-39Zn-1Al-3Mn) are described. In machining ductile brass with formation of a continuous chip, extreme pattern of normal σh and tangential τh contact stresses epures (curves of distribution) over a flank land is observed, i.e. the highest contact stress is at some distance from the cutting edge. In machining brittle brass with formation of a discontinuous chip, the highest contact stress is observed, on the contrary, near the cutting edge. The character of normal contact stresses over a flank-land depends on the type of the chip formation due to a sag of the transient surface under the act of a radial component of the cutting force on the rake surface.

2018 ◽  
Vol 769 ◽  
pp. 364-370
Author(s):  
Victor Kozlov ◽  
Jia Yu Zhang ◽  
Ying Bin Guo ◽  
Sai Kiran Sabavath

The paper presents data about distribution of contact stresses on a rake surface and flank-land of a cutter in free orthogonal turning of a disk made from a titanium alloy (Ti-6Al-2Mo-2Cr). On the cutting edge of the bar blade, there is a normal force Nρ, directed perpendicularly to a transient surface, with a large magnitude of specific linear force qN r= 182.6 N/mm, but the tangential force on the cutting edge Fρis equal to zero. On the rake surface, there are uniformly distributed shear contact stresses with very small magnitude of τ ≈ const ≈ 25 MPa, irrespective of feed rate, which speaks about plastic character of the contact on the rake surface. The greatest normal contact stress on the rake surface σmax≈ 1009 MPa, irrespective of feed rate. The greatest magnitude of normal contact stresses on the flank surface chamfer near the cutting edge σh max= 3400-2200 MPa confirms the hypothesis about recovery of a transient surface sag after separation of a formed element of a chip, and explains increased wear of the cutting tool on the flank surface at initial time. Normal σhand shear τhcontact stresses on the flank surface chamfer are essentially diminish with a distance from the cutting edge. It explains working ability of the cutting tool even at very large wear on the flank surface (hf> 3 mm). Our experimental data allows calculating the components of cutting force and contact stresses on the rake and flank surfaces of cutting tools during titanium alloy (Ti-6Al-2Mo-2Cr) machining.


2017 ◽  
Vol 743 ◽  
pp. 252-257 ◽  
Author(s):  
Victor Kozlov ◽  
Jia Yu Zhang ◽  
Ekaterina Letshiner ◽  
Wen Ze Zhao

This paper analyses the results of experimental research of contact stresses distribution over an artificial flank wear-land and temperature distribution in a cutting wedge in a free orthogonal turning of the disk made from titanium alloy (Ti-6Al-2Mo-2Cr) by a cutter with a sharp-cornered edge and with a rounded cutting edge. The investigation was carried out by the method of “split cutter” (sectional tool) and method of variable length of an artificial flank wear land. Experiments with variable feed rate and cutting speed show that in titanium alloy machining with a sharp-cornered cutting edge, the highest normal contact stress over the flank land (σh max = 3400…2200 MPa) is observed immediately at the cutting edge, and the curve has a horizontal region with a length of 0.2…0.6 mm. At larger distance from the cutting edge, the value of normal contact stress is dramatically reduced to 1100…500 MPa. The character of normal contact stresses for a rounded cutting edge is different: it is uniform and its value is approximately 2 times smaller as compared to machining with sharp-cornered cutting edge. In author’s opinion it is connected with generation of a seizure zone in chip formation region and explains working capacity of very worn-out cutting tools in machining titanium alloys. The results of experimental research of temperature distribution in the cutting tool wedge show that temperature reaches 1000 °С at essential wear over the flank surface. Such high value of temperature on the contact surface causes softening of work material, and explains the small value of tangential contact stresses (τh = 800…200 MPa) and reduction of normal contact stresses σh far from the cutting edge for a sharp-cornered cutting edge.


2018 ◽  
Vol 769 ◽  
pp. 284-289
Author(s):  
Victor Kozlov ◽  
Jia Yu Zhang ◽  
Ying Bin Guo ◽  
Sai Kiran Sabavath

The paper presents the distribution of contact stresses on the flank land of a cutter during steel turning (Fe-0.4C-1Cr) at the initial time of cutting. Plunge-cutting into a steel workpiece by the whole length of the cutting tool edge features almost twofold short-term increase of in cutting force components in comparison with stable cutting. Such increase is absent, if the feed rate exceeds 0.34 mm/rev and the cut depth exceeds 2 mm. This is explained by sagging of the cutting surface under the influence of the dead zone in the area of the cutting edge, which moves before the cutting tool and reduces the contact interaction of the flank surface chamfer with the workpiece. The contact stresses on the flank surface chamfer increase with the distance from the cutting edge, which is explained by recovered cutting surface sag, conditioned by the action of the dead zone in the cutting edge area. This increase accelerates with the reduction in the feed rate. Normal contact stresses increase more quickly on a flank-land at a distance from the cutting edge of more than 0.8 mm, which is explained by recovering of a transient surface sag, and explains the increase in the probability of cutting wedge destruction when the length of flank-land wear exceeds 1.2 mm.


2021 ◽  
Author(s):  
Weiwei Zhang ◽  
Jian Weng ◽  
Kejia Zhuang ◽  
Cheng Hu ◽  
Xing Dai ◽  
...  

Abstract Cutting tools with round edge can enhance the performance of machining difficult-to-machine materials, while the complex contact mechanism related to micro cutting edge limits the deeper understanding of cutting mechanics. Material separation, which is associate to plough mechanism with formation of dead metal zone (DMZ), also requires the analysis of contact behavior. This study develops a contact model along the round edge together with the illustration of DMZ, with three contact feature points defined to explain the contact situation between workpiece and cutting edge. Among these feature points, two separation points related to DMZ classify the sliding and sticking region considering the dual-zone approach. The stagnation point is the zero shear stress point where a sudden change in shear stress direction happens. Besides, the parabolic stress model obtained from finite element simulations is established to define the normal contact distribution along the round edge. In this basis, the tool-based frictional forces are determined and two contact force components are classified for different contact regions. The proposed contact feature points and contact stress are validated through illustration with finite element simulations. Besides, orthogonal cutting tests ensure the practicality and accuracy of the proposed contact model and predicted cutting forces.


2012 ◽  
Vol 565 ◽  
pp. 359-364 ◽  
Author(s):  
Masahiro Furuno ◽  
Koichi Kitajima ◽  
Takeshi Akamatsu

The results of an investigation on the effects of surface roughness on ball end mill are reported here. We used grindwheels with varying in grit between #325 and #1000 to grind ball end mill’s rake surface and flank surface, and then coated the end mill with TiAlN film, CrSiN film, and TiSiN film. We measured the state of adhesion on the films on the rake surface in continuous lathe milling as well as the surface roughness and cutting force. The results show that, in generating the cutting cutoff, the optimum grinding roughness differs between the near vicinity of the cutting-edge ridgeline and the part of the rake surface that is further away from the cutting-edge ridgeline. From that fact, we understand that the cutting characteristics of the work material and the surface area of the rake surface that is in contact with the cutting cutoff exert their respective influences during the cutting.


Author(s):  
Xuesong Jin ◽  
Jun Guo ◽  
Xinbiao Xiao ◽  
Zefeng Wen

Some important papers concerning the studies on rail wear and wheel/rail contact stresses are reviewed. The present paper utilizes a numerical method to analyze the effect of railway vehicle curving on the wear and contact stresses of wheel/rail. The numerical method considers a combination of Kalker’s non-Hertzian rolling contact theory, a material wear model and a vertical and lateral coupling dynamics model of a half vehicle and a curved track. The present analysis investigates the influence of the curving speed, the curved track super-elevation and the rail cant on the wear and the contact stresses. Through the detailed numerical analysis, it is found that the maximum contact stress depends greatly not only on the curving speed but also on the profiles of the wheel/rail. The curving speed increasing leads to increase the normal load of the wheel rolling over the high curved rail, but, decrease the normal contact stress level under the condition of the optimum match of wheel/rail profiles. The track super elevation increasing efficiently lowers the contact stresses and the wear at a constant curving speed. The rail cant has a great influence on the low rail wear of the curved track. Increasing the rail cant leads to the great growth of the low curved rail wear, the reduction in the high rail wear. The results are very useful in the maintenance of the track.


2014 ◽  
Vol 8 (6) ◽  
pp. 837-846 ◽  
Author(s):  
Norikazu Suzuki ◽  
◽  
Risa Enmei ◽  
Yohei Hashimoto ◽  
Eiji Shamoto ◽  
...  

A series of high-speed milling tests of Inconel 718 were carried out utilizing SiAlON ceramic tools, and the transitions of the cutting edge geometry and cutting forces were investigated. Through the experimental investigations, it was confirmed that the cutting edge is worn rapidly and a round shape is formed at the initial stage of machining. The radius of the round cutting edge becomes considerably large with respect to the uncut chip thickness, and thus the ploughing process is dominant in ceramic milling like general micro cutting operations. Based on the observed phenomena, a quasi-mechanistic model for cutting force prediction was proposed, where the measured cutting edge geometry and the contact stress distribution at the toolworkpiece interface are taken into account. The estimated cutting force by the proposed model showed a good agreement with the measured one. Minimizing the estimation error in the cutting forces, contact stresses of the cutting edge to the workpiece are identified. Stress field analysis using the estimated contact stresses revealed that the large tensile stress instantaneously generates around the stagnation point. This mechanism may contribute to the generation of the rake face flaking, which determines the end of the tool life.


2019 ◽  
Vol 6 (2) ◽  
pp. e31-e35
Author(s):  
A. V. Yavtushenko ◽  
V. M. Protsenko ◽  
Y. V. Bondarenko ◽  
A. G. Kirichenko ◽  
F. Y. Ping

The possibility of application of the program complex called Mathcad Prime 5 for calculation of normal contact stresses in the center of deformation during cold rolling of the strips is considered. The algorithm, the block-scheme and the computer program of calculation of the normal contact stresses during rolling of the strips on the reverse mill 1680 PJSC “Zaporizhstal” are developed. The epures were constructed and a comparative analysis of the formulas used to calculate the normal contact stresses in the deformation center was carried out. Received calculation data in Mathcad Prime 5 coincides with the literary data, which has practical value for both educational process and research and design work. Based on the analysis of the contact stress epures, it can be concluded that the most accurate calculation of the total metal pressure on the rolls during cold rolling is possible only when the formulas used to consider the change in the forced yield strength in the deformation center by the law of a straight line or the parabolic law. Keywords: CAD, CAE, block-crankcase, 3D model, casting defect.


Author(s):  
Angeli Jayme ◽  
Imad L. Al-Qadi

A thermomechanical coupling between a hyper-viscoelastic tire and a representative pavement layer was conducted to assess the effect of various temperature profiles on the mechanical behavior of a rolling truck tire. The two deformable bodies, namely the tire and pavement layer, were subjected to steady-state-uniform and non-uniform temperature profiles to identify the significance of considering temperature as a variable in contact-stress prediction. A myriad of ambient, internal air, and pavement-surface conditions were simulated, along with combinations of applied tire load, tire-inflation pressure, and traveling speed. Analogous to winter, the low temperature profiles induced a smaller tire-pavement contact area that resulted in stress localization. On the other hand, under high temperature conditions during the summer, higher tire deformation resulted in lower contact-stress magnitudes owing to an increase in the tire-pavement contact area. In both conditions, vertical and longitudinal contact stresses are impacted, while transverse contact stresses are relatively less affected. This behavior, however, may change under a non-free-rolling condition, such as braking, accelerating, and cornering. By incorporating temperature into the tire-pavement interaction model, changes in the magnitude and distribution of the three-dimensional contact stresses were manifested. This would have a direct implication on the rolling resistance and near-surface behavior of flexible pavements.


2018 ◽  
Vol 8 (8) ◽  
pp. 1353
Author(s):  
Tao Chen ◽  
Fei Gao ◽  
Suyan Li ◽  
Xianli Liu

Carbon fiber reinforced plastic (CFRP) is typically hard to process, because it is easy for it to generate processing damage such as burrs, tears, delamination, and so on in the machining process. Consequently, this restricts its wide spread application. This paper conducted a comparative experiment on the cutting performance of the two different-structure milling cutters, with a helical staggered edge and a rhombic edge, in milling carbon fiber composites; analyzed the wear morphologies of the two cutting tools; and thus acquired the effect of the tool structure on the machined surface quality and cutting force. The results indicated that in the whole cutting, the rhombic milling cutter with a segmented cutting edge showed better wear resistance and a more stable machined surface quality. It was not until a large area of coating shedding occurred, along with chip clogging, that the surface quality decreased significantly. At the stage of coating wear, the helical staggered milling cutter with an alternately arranged continuous cutting edge showed better machined surface quality, but when the coating fell off, its machined surface quality began to reveal damage such as groove, tear, and fiber pullout. Meanwhile, burrs occurred at the edge and the cutting force obviously increased. By contrast, for the rhombic milling cutter, both the surface roughness and cutting force increased relatively slowly.


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