scholarly journals Comparison Analysis Between Simulation and Experiment of Cutting Force and Cutting Stress as Well as Chip Morphology During the Macro and Nano Cutting of Single Crystal Copper

Author(s):  
Dongju Chen ◽  
Shuiyuan Wu ◽  
Yazhong He ◽  
Shupei Li ◽  
Yuchi Luo ◽  
...  

Abstract In this paper, the simulation and experiment comparison of cutting force, cutting stress and chip morphology during the macro and nano cutting of single crystal copper are carried out. Firstly, a finite element method based on Johnson-Cook metal strength and failure model were used to establish a macro cutting model, and the cutting force, cutting stress, cutting displacement and chip morphology were obtained. Then a molecular dynamics simulation was used to establish a nano cutting model, and the cutting force, von mises stress and chip morphology were obtained. Afterwards, a comparative analysis of the two was carried out. Finally, the external turning experiment was used to verify the simulation results of the macro cutting model. The results show that: 1. The change trend of the cutting force in x and y directions are different,but the corresponding ratios of cutting forces in x and y directions in macro and nano cutting process are very close, and the corresponding ratios of the average macro and nano cutting forces in x and y directions are also very close. 2. The cutting stress in nano cutting process was about 100 times of macro cutting stress. 3. The chip length in macro cutting process is larger than the chip length in nano cutting process, and the shape is more regular. 4. The experimental cutting force change trend is very similar to the simulation cutting force change trend, but there exits difference in the value between the experiment cutting forces and simulated cutting forces.

Author(s):  
Weilong Niu ◽  
Rong Mo ◽  
Huibin Sun ◽  
Balachander Gnanasekaran ◽  
Yihui Zhu ◽  
...  

The saw-tooth chip formation is one of the main machining characteristics in cutting of titanium alloys. The numerical simulation of saw-tooth chip formation, however, is still not accurate, since most of these numerical simulation models are based on traditional finite element method, which have difficulties in handling extremely large deformation that always occurs in the cutting process. Furthermore, these models adopt the Johnson–Cook damage constitutive law that is implemented in commercial codes such as ABAQUS® and LS-DYNA® to describe the dynamic mechanical properties of material, but Johnson–Cook damage constitutive law cannot account for the material of behavior due to strain softening and the dynamic recrystallization mechanism that occurs in the cutting process of Ti–6Al–4. Therefore, this work introduces a material constitutive model named hyperbolic tangent (TANH) and an improved smooth particle hydrodynamics method, and then develops an improved cutting model for Ti–6Al–4V titanium alloy through our in-house code to predict saw-tooth chip morphology and cutting forces. When compared to the experiments and Johnson–Cook damage model, the improved cutting model better explains and predicts the shear localized saw-tooth chip deformation as well as cutting forces.


Author(s):  
Xiangqin Zhang ◽  
Xueping Zhang ◽  
A. K. Srivastava

To predict the cutting forces and cutting temperatures accurately in high speed dry cutting Ti-6Al-4V alloy, a Finite Element (FE) model is established based on ABAQUS. The tool-chip-work friction coefficients are calculated analytically using the measured cutting forces and chip morphology parameter obtained by conducting the orthogonal (2-D) machining tests. It reveals that the friction coefficients between tool-work are 3∼7 times larger than that between tool-chip, and the friction coefficients of tool-chip-work vary with feed rates. The analysis provides a better reference for the tool-work-chip friction coefficients than that given by literature empirically regardless of machining conditions. The FE model is capable of effectively simulating the high speed dry cutting process of Ti-6Al-4V alloy based on the modified Johnson-Cook model and tool-work-chip friction coefficients obtained analytically. The FE model is further validated in terms of predicted forces and the chip morphology. The predicted cutting force, thrust force and resultant force by the FE model agree well with the experimentally measured forces. The errors in terms of the predicted average value of chip pitch and the distance between chip valley and chip peak are smaller. The FE model further predicts the cutting temperature and residual stresses during high speed dry cutting of Ti-6Al-4V alloy. The maximum tool temperatures exist along the round tool edge, and the residual stress profiles along the machined surface are hook-shaped regardless of machining conditions.


2006 ◽  
Vol 5-6 ◽  
pp. 367-374
Author(s):  
C. G. Dumitraş

Due to robotic deburring development, the research gains a new orientation and focused on the cutting forces and the chip control. The present paper will emphasize the main difference which occurs between the normal cutting process and the deburring process, the way it develops and the parameters which characterize this process. Also the dynamics of the process are considered. Based on a central composite design one determine a relation between the geometry of the tool, workpiece hardness and cutting force.


2013 ◽  
Vol 690-693 ◽  
pp. 2559-2562
Author(s):  
Ying Zhu ◽  
Shun He Qi ◽  
Zhi Xiang ◽  
Ling Ling Xie

Molecular dynamics model of the polysilicon material under the micro/nanoscale is established by using molecular dynamics method, make variety of the typical defects distribute to the polysilicon model reasonable and relax the simulation model, obtain the system potential energy curves in the relaxation process and the atomic location figure after the relaxation. Conduct molecular dynamics simulation of nanometric cutting process relying on the development of simulation program, get instant atom position image and draw the cutting force curve. Discusses the typical defects impact on the polycrystalline silicon nanometric cutting process, those mainly include cutting force changes in the cutting process, potential energy changes and processed surface quality etc.


2006 ◽  
Vol 532-533 ◽  
pp. 753-756 ◽  
Author(s):  
Jun Zhao ◽  
Xing Ai ◽  
Zuo Li Li

The Finite Element Method (FEM) has proven to be an effective technique to investigate cutting process so as to improve cutting tool design and select optimum cutting conditions. The present work focuses on the FEM simulation of cutting forces in high speed cutting by using an orthogonal cutting model with variant undeformed chip thickness under plane-strain condition to mimic intermittent cutting process such as milling. High speed cutting of 45%C steel using uncoated carbide tools are simulated as the application of the proposed model. The updated Lagrangian formulation is adopted in the dynamic FEM simulation in which the normalized Cockroft and Latham damage criterion is used as the ductile fracture criterion. The simulation results of cutting force components under different cutting conditions show that both the thrust cutting force and the tangential cutting force increase with the increase in undeformed chip thickness or feed rate, whereas decrease with the increase in cutting speed. Some important aspects of modeling the high speed cutting are discussed as well to expect the future work in FEM simulation.


2011 ◽  
Vol 239-242 ◽  
pp. 2775-2778
Author(s):  
Jia Xuan Chen ◽  
Ying Chun Liang ◽  
Xia Yu ◽  
Zhi Guo Wang ◽  
Zhen Tong

To study the removal mechanism of materials during nano cutting, molecular dynamics method is adopted to simulate single crystal copper nanomachining processes, and subsurface defects evolvements and chip forming regulation are analyzed by revised centro-symmetry parameter method and the ratios of the tangential cutting forceand the normal cutting force. The results show that there are different defects under different cutting depths. When cutting depths is shallower, there are dislocation loop nucleation in the subsurface of the workpiece beneath the tool; however, when the cutting depths is deeper, there are dislocations nucleation and slipping along {101} plane and (111) plane. In addition, both tangential cutting forceand the normal cutting force decrease as the cutting depths decreasing. When the ratios of the normal cutting force and the tangential cutting force is below 0.9, the chip will be formed.


2010 ◽  
Vol 97-101 ◽  
pp. 1961-1964 ◽  
Author(s):  
Wei Guo Wu ◽  
Gui Cheng Wang ◽  
Chun Gen Shen

In this work, the prediction and analysis of cutting forces in precision turning operations is presented. The model of cutting forces is based on the oblique cutting force model which was rebuilt by two coordinate conversions from the orthogonal cutting model. Then the cutting field in precision turning was divided into two fields which are characterized as curve change and linear change on cutter edge and they were modeled respectively. Cutting field of cutter nose was modeled by differential method and its cutting force distribution is predicted by the proposed method. The predicted results for the cutting forces are in agreement with the experimental results under a variety of operation variables, including changes in the depths of cut and in the feedrate.


1967 ◽  
Vol 89 (2) ◽  
pp. 347-355 ◽  
Author(s):  
Russell F. Henke

This paper is the latest of a continuing series on the subject of self-excited machine tool chatter. The representation of the metal cutting process as required by the previously developed closed-loop chatter theory is extended to oblique cutting with tools of practical shape and geometry. The cutting process parameters essential to proper application of the stability theory are found by an analytical formulation leading to a classical eigenvalue problem. Techniques are developed to determine the steady-state constant of proportionality between resultant cutting force and uncut chip area, the direction of resultant cutting force, and the direction of maximum cutting stiffness for any single-point cutting operation. In the process, a general method to predict steady-state oblique cutting forces is evolved. The method depends on certain experimentally justifiable assumptions and utilizes previously compiled orthogonal cutting data.


2011 ◽  
Vol 421 ◽  
pp. 123-128 ◽  
Author(s):  
Hong Wei Zhao ◽  
Lin Zhang ◽  
Peng Zhang ◽  
Cheng Li Shi

A series of three-dimension molecular dynamics (MD) simulations are performed using hybrid potentials to investigate nanometric cutting process of single-crystal copper with diamond tool. The effect of tool geometry in nanometric cutting process is investigated. It is observed that with the negative rake angle, the volume of chips becomes smaller due to large hydrostatic pressure and plastic deformation generated in the subsurface layer. When the rake angle changes from -40° to 40°, the machined surface becomes smoother. Besides, the ratio of tangential force to normal force decreases with the increase of rake angle. In addition, the effect of clearance angle is analyzed and approximate entropy (APEN) is presented to denote the complexity and uncontrollability of the interactions between tool and workpiece with different clearance angles. With the decrease of clearance angle, the machined surface quality decreases with the local stress distribution in subsurface layer is uneven. An appropriate clearance angle not only keeps cutting force stable, but makes sure of the quality of machined surface as well.


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