The Characteristics of Titanium Alloy Chip-Breaking by Orthogonal Cutting with a Surface-Textured Cutting Tool

2013 ◽  
Vol 365-366 ◽  
pp. 1235-1239 ◽  
Author(s):  
Jian Fu Zhang ◽  
Zhi Meng Chen ◽  
Ping Fa Feng ◽  
Wan Hong Xu

A comparative experimental study on the orthogonal cutting of titanium alloys by a polished tool, a tool containing a chip breaker groove, and a surface-textured tool was performed. The effects of different cutting tools on chip morphology, chip thickness, length and width of crack defects inside the chip, saw-teeth of the chip, and chip curl radius were analyzed during the cutting of a titanium alloy. Compared to chips formed by other tools, curled chip fragments formed by the surface-textured tool exhibited greater thickness and longer crack defect depths but smaller chip tooth pitches and curvature radii. The microstructural mechanisms involved in the interaction between the micro-texture surface cutting tool and the chips were analyzed by evaluating the cutting and texture parameters. The chip-breaking mechanism is that the micro-texture on the tool surface creates a sticky texture, leading to the micro-cutting and wrenching of chips, thereby increasing the magnitude of the tools work-hardening and chip-breaking effects.

2011 ◽  
Vol 223 ◽  
pp. 3-11 ◽  
Author(s):  
François Ducobu ◽  
Edouard Rivière-Lorphèvre ◽  
Enrico Filippi

The foundations of micro-milling are similar to macro-milling but the phenomena it involves are not a simple scaling-down of macro-cutting. The importance of the minimum chip thickness is one of the significant differences between the two processes. The lagrangian FEM model presented in this paper aims to study the depth of cut influence on chip formation of Ti6Al4V in orthogonal cutting. It is firstly used to compare the modelled saw-toothed macro-chip morphology and cutting forces to experimental cutting results from literature. Then a minimum chip thickness prediction is performed by decreasing the depth of cut. Finally this study is the opportunity to highlight the specific features of micro-cutting reported in literature, such as the effective negative rake angle of the tool or the size effect. The model presented brings therefore a numerical contribution to the comprehension of these phenomena.


2011 ◽  
Vol 487 ◽  
pp. 39-43 ◽  
Author(s):  
L. Tian ◽  
Yu Can Fu ◽  
W.F. Ding ◽  
Jiu Hua Xu ◽  
H.H. Su

Single-grain grinding test plays an important part in studying the high speed grinding mechanism of materials. In this paper, a new method and experiment system for high speed grinding test with single CBN grain are presented. In order to study the high speed grinding mechanism of TC4 alloy, the chips and grooves were obtained under different wheel speed and corresponding maximum undeformed chip thickness. Results showed that the effects of wheel speed and chip thickness on chip formation become obvious. The chips were characterized by crack and segment band feature like the cutting segmented chips of titanium alloy Ti6Al4V.


Author(s):  
Yun Chen ◽  
Huaizhong Li ◽  
Jun Wang

Titanium and its alloys are difficult to machine due to their high chemical reactivity with tool materials and low thermal conductivity. Chip segmentation caused by the thermoplastic instability is always observed in titanium machining processes, which leads to varied cutting forces and chip thickness, etc. This paper presents an analytical modelling approach for cutting forces in near-orthogonal cutting of titanium alloy Ti6Al4V. The catastrophic shear instability in the primary shear plane is assumed as a semi-static process. An analytical approach is used to evaluate chip thicknesses and forces in the near-orthogonal cutting process. The shear flow stress of the material is modelled by using the Johnson–Cook constitutive material law where the strain hardening, strain rate sensitivity and thermal softening behaviours are coupled. The thermal equations with non-uniform heat partitions along the tool–chip interface are solved by a finite difference method. The model prediction is verified with experimental data, where a good agreement in terms of the average cutting forces and chip thickness is shown. A comparison of the predicted temperatures with published data obtained by using the finite element method is also presented.


2021 ◽  
Vol 40 (1) ◽  
pp. 77-86
Author(s):  
Siwen Tang ◽  
Pengfei Liu ◽  
Zhen Su ◽  
Yu Lei ◽  
Qian Liu ◽  
...  

Abstract Al2O3 nano-scaled coating was prepared on micro-textured YT5 cemented carbide cutting tools by atomic layer deposition ALD. The effect of Al2O3 nano-scaled coating, with and without combined action of texture, on the cutting performance was studied by orthogonal cutting test. The results were compared with micro-textured cutting tool and YT5 cutting tool. They show that the micro-texture and nano-scaled Al2O3 coated on the micro-texture both can reduce the cutting force and friction coefficient of the tool, and the tools with nano-scaled Al2O3 coated on the micro-texture are more efficient. Furthermore, the friction coefficient of the 100 nm Al2O3-coated micro-texture tool is relatively low. When the distance of the micro-pits is 0.15 mm, the friction coefficient is lowest among the four kinds of pit textured nanometer coating tools. The friction coefficient is the lowest when the direction of the groove in strip textured nanometer coating tool is perpendicular to the main cutting edge. The main mechanism of the nanometer Al2O3 on the micro-textured tool to reduction in cutting force and the friction coefficient is discussed. These results show that the developed tools effectively decrease the cutting force and friction coefficient of tool–chip interface.


Author(s):  
Nejah Tounsi ◽  
Tahany El-Wardany

Abstract Part I of these two-part papers will investigate the effect of three FEM representations of the milling process on the prediction of chip morphology and residual stresses (RS), when down-milling small uncut chips with thickness in the micrometer range and finite cutting edge radius. They are: i) orthogonal cutting with the mean uncut chip thickness t, obtained by averaging the uncut chip thickness over the cutting length, ii) orthogonal cutting with variable t, which characterizes the down-milling process and which is imposed on a flat surface of the final workpiece, and iii) modelling the true kinematics of the down milling process. The appropriate constitutive model is identified through 2D FEM investigation of the effects of selected constitutive equations and failure models on the prediction of RS and chip morphology in the dry orthogonal machining of Ti6Al4V and comparison to experimental measurements. The chip morphology and RS prediction capability of these representations is assessed using the available set of experimental data. Models featuring variable chip thickness have revealed the transition from continuous chip formation to the rubbing mode and have improved the predictions of residual stresses. The use of sequential cuts is necessary to converge toward experimental data.


2022 ◽  
Vol 73 ◽  
pp. 183-196
Author(s):  
Qiang Fu ◽  
Shujing Wu ◽  
Changhe Li ◽  
Jinyang Xu ◽  
Dazhong Wang

2009 ◽  
Vol 407-408 ◽  
pp. 420-423
Author(s):  
He Ping Wang ◽  
Xue Ping Zhang

An explicit dynamic coupled thermal-mechanical Arbitrary Lagrangian Eulerian (ALE) model was established to simulate orthogonal cutting AISI 52100 bearing steel, and its temperature and stress distribution. Based on ABAQUS, The ALE approach effectively simulates plastic flow around round edge of the cutting tool without employing chip separation criteria. The calculation results reveal that cutting speed and cutting depth have great impact on chip morphology, stress and temperature distribution in the finished surface and subsurface, the predicted temperature agrees well with experiment data obtained under the similar cutting conditions as well as the change in chip morphology from continuous to sawtooth as the cutting speed increases.


Author(s):  
N Fang

Traditionally, cutting tools made of sintered carbides or high-speed steels are used to cut a variety of metal materials in the experimental study on chip control. One of the existing problems is that, in most cases, it is difficult to make, in a laboratory, cutting tools with a three-dimensionally shaped chip breaking groove for use in the follow-up experiments. Turning to tool manufacturers, who use the powder metallurgy techniques of tool making for help, usually leads to a long experimental period and high cost. An auxiliary approach to the experimental study on chip control, called a kinematically simulated test (KST), is proposed in this present work to overcome the above shortcoming of the traditional method employed in the experimental study on chip control. A plexiglass-made cutting tool is employed to cut a commercially available paraffin wax to simulate some kinematic phenomena (such as chip flow and chip curl) which take place during practical machining processes. After the applied range of KST has been illustrated, two examples of applying KST are given. One is the application of KST to chip flow research. The other is optimizing the geometry of the chip breaking groove of a tool insert by means of KST. Both examples involve the making of the chip breaking grooves with the three-dimensional shape and geometry.


2010 ◽  
Vol 37-38 ◽  
pp. 550-553
Author(s):  
Xin Li Tian ◽  
Zhao Li ◽  
Xiu Jian Tang ◽  
Fang Guo ◽  
Ai Bing Yu

Tool edge radius has obvious influences on micro-cutting process. It considers the ratio of the cutting edge radius and the uncut chip thickness as the relative tool sharpness (RST). FEM simulations of orthogonal cutting processes were studied with dynamics explicit ALE method. AISI 1045 steel was chosen for workpiece, and cemented carbide was chosen for cutting tool. Sixteen cutting edges with different RTS values were chosen for analysis. Cutting forces and temperature distributions were calculated for carbide cutting tools with these RTS values. Cutting edge with a small RTS obtains large cutting forces. Ploughing force tend to sharply increase when the RTS of the cutting edge is small. Cutting edge with a reasonable RTS reduces the heat generation and presents reasonable temperature distributions, which is beneficial to cutting life. The force and temperature distributions demonstrate that there is a reasonable RTS range for the cutting edge.


2011 ◽  
Vol 694 ◽  
pp. 616-619
Author(s):  
Peng Zhang ◽  
Xing Yu Guo ◽  
Kang Pei Zhao ◽  
Li You Zhu

It is often one of the most important issues for chip breaking and chip removal problems in the hole machining process, especially for micro hole. The chip breaking mechanism of the vibration drilling is researched, and its chip breaking conditions is analyzed. The micro drilling experiments are carried to contrast the chip shape of common drilling and vibration one. It can be draw that the vibration drilling can realize the regular chip breaking, which is beneficial to chip removal in hole machining, the chip breaking feature is one of the fine process effects. This work further enriches the vibration drilling technology.


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