Analysis of Burr Formation Mechanism in Orthogonal Cutting

1999 ◽  
Vol 121 (1) ◽  
pp. 1-7 ◽  
Author(s):  
M. Hashimura ◽  
Y. P. Chang ◽  
David Dornfeld

To prevent problems caused by burrs in machining, reduction and control of burr size is desirable. This paper presents a basic framework for and conceptual understanding of the burr formation process based upon the material properties of the workpiece. In order to verify this framework and explain the basic phenomena in the burr formation process, the deformation at the edge of the workpiece was analyzed using a finite element method (FEM). Micro-machining tests under an optical microscope and a scanning electron microscope using Al-2024-O material were also done to observe the burr formation process. The feed rate and tool edge radius were varied and the resulting burr formation observed. FEM analysis of burr formation in the 2024 material and observation of the deformation at the workpiece edge in the micro-machining tests verified the proposed conceptual understanding of the burr formation process. For the experimental conditions examined, all of the burrs in Al-2024-O were “negative” burrs, that is, edge breakout. As the feed was increased two effects were observed. One effect was an increase in the resulting burr thickness. Another effect, which was observed during the burr initiation stage while machining with a sharp tool, was an increase in both the distance and depth of the initial pivoting point of the burr from the tool edge.

1996 ◽  
Vol 118 (2) ◽  
pp. 201-206 ◽  
Author(s):  
Gwo-Lianq Chern ◽  
David A. Dornfeld

The mechanisms of burr formation and breakout in orthogonal cutting are analyzed. A burr formation/breakout model for orthogonal cutting is proposed, based on the observation of SEM micro-machining tests. It is found that a negative deformation plane begins to form when the steady-state chip formation stops as the tool approaches the end of the cut. Plastic bending and shearing of the negative deformation plane contributes to the burr formation, while crack propagation along the plane causes the breakout. Simulated orthogonal cutting experiments using copper, Al 2024-T4, and Al 6061-T6 were performed with a modified impact machine to verify the model. The tests showed excellent agreement with the model predictions.


2007 ◽  
Vol 24-25 ◽  
pp. 249-254 ◽  
Author(s):  
Hai Jun Qu ◽  
Gui Cheng Wang ◽  
Hong Jie Pei ◽  
Qin Feng Li ◽  
Yun Ming Zhu

The cutting-direction burr is one of the important factors that influence the edge quality and performance of precision parts. The cutting-direction burr formation process is simulated with DeformTH3D. The mechanism of cutting-direction burr formation is analyzed in terms of the results of the simulation. The negative shear zone and initiation negative shear angle are discussed too. Study results show that the deformation of CDE is an important factor affect the cutting direction burrs’ size and shape.


2008 ◽  
Vol 53-54 ◽  
pp. 77-82 ◽  
Author(s):  
Hai Jun Qu ◽  
Gui Cheng Wang ◽  
Yun Ming Zhu ◽  
Qin Xi Shen

The two-side burr is one of the important factors that influence the edge quality and performance of precision parts. The two side-direction burr formation process is simulated with DeformTH3D. The mechanism of two-side burr formation is analyzed in terms of the results of the simulation. Enlarging the tool orthogonal rake and minimizing the depth of cut can reduce the burr size.


2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110090
Author(s):  
Xuefeng Zhao ◽  
Hao Qin ◽  
Zhiguo Feng

Tool edge preparation can improve the tool life, as well as cutting performance and machined surface quality, meeting the requirements of high-speed and high-efficiency cutting. In general, prepared tool edges could be divided into symmetric or asymmetric edges. In the present study, the cemented carbide tools were initially edge prepared through drag finishing. The simulation model of the carbide cemented tool milling steel was established through Deform software. Effects of edge form factor, spindle speed, feed per tooth, axial, and radial cutting depth on the cutting force, the tool wear, the cutting temperature, and the surface quality were investigated through the orthogonal cutting simulation. The simulated cutting force results were compared to the results obtained from the orthogonal milling experiment through the dynamometer Kistler, which verified the simulation model correctness. The obtained results provided a basis for edge preparation effect along with high-speed and high effective cutting machining comprehension.


2010 ◽  
Vol 152-153 ◽  
pp. 1058-1061
Author(s):  
Zhou Wei ◽  
Xiao Xia Zhang

A wedged load test method is used to evaluate the adhesion strength of high-strength coatings, which have been processed with various sintering parameters. In this test, for stress concentration at cut tip, cracks are always induced and expanded rapidly cross the interface between coating and substrate. Macro-fracture and SEM image of coating interface of high-strength coating are characterized using optical microscope and scanning electron microscopy (SEM), respectively. In order to evaluate the bonding properties between coating and substrate effectively, corresponding finite element (FE) analysis has been conducted to evaluate the adhesion strength of high-strength coating. And stress distributions cross the interface of high-strength coating are obtained. The stress analysis can help to evaluate the bond strength of high-strength coating. Because of small specimen and contact relationship between wedged pressure head and wedged cuts, complex stress state is affected by many factors resulting from interface, and also by the thickness of coating.


2007 ◽  
Vol 31 (2) ◽  
pp. 122-129 ◽  
Author(s):  
Gwo-Lianq Chern ◽  
Ying-Jeng Engin Wu ◽  
Jyun-Cheng Cheng ◽  
Jian-Cheng Yao

2007 ◽  
Vol 21 (3) ◽  
pp. 253-258 ◽  
Author(s):  
Tomie Nakakuki Campos ◽  
Cleber Henrique Inoue ◽  
Elcio Yamamoto ◽  
Ângela Toshie Araki ◽  
Lena Katekawa Adachi ◽  
...  

There are situations in which intraradicular retainers have to be removed and replaced. The objective of this research was to evaluate the apical seal after the removal of a custom cast post and core with a carbide bur or with an ultrasound apparatus. Twenty five roots of extracted human incisors were used. They were endodontically treated and prepared to receive the posts. The posts and cores were cast with 2 types of dental alloys, CuAlZn and PdAg, and were cemented with zinc phosphate cement. After 24 hours, they were removed using the two above mentioned techniques. Then, the roots had their external surface made impermeable by two layers of cyanoacrylate adhesive, leaving only the cervical area for dye penetration. The teeth were immersed in rhodamine for 24 hours. They were then cut and observed under an optical microscope and analyzed with appropriate software (Imagelab). The results were submitted to ANOVA, and they evidenced that, regarding the alloy factor, PdAg posts presented a larger mean infiltration value (2.23 ± 0.48 mm) as compared to the posts made of CuAlZn (1.39 ± 0.48 mm) (p = 0.025). Regarding the technique factor, there was no significant difference (p = 0.9) between the removal of the intraradicular retainer using ultrasound (1.99 ± 0.62 mm) or using a rotating cutting instrument (1.62 ± 0.62 mm). Under these experimental conditions, it was possible to conclude that the degree of apical leakage was directly related to the alloy type, and it was present in both techniques used.


Author(s):  
Vijay M. Sundaram ◽  
Sy-Bor Wen

Nano-patterns are generated on semiconducting and metallic surfaces through coupling an apertured near field scanning optical microscope (NSOM) with a pulsed laser source in this study. To understand the dominant mechanisms for the generation of the nano-patterns, a series of experimental measurement of the size and shape of nano-patterns generated on targets under different experimental conditions with different targets is conducted. The characteristic dimensions of nano-patterns show dependence on optical properties of the target material. The qualitative trend of the variation of nano-patterns as a function of laser and material conditions indicates that the dominant mechanisms for the generation of nano-patterns through a combination of nanosecond laser and an apertured NSOM under different conditions studied is near field laser-material interaction.


Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 276 ◽  
Author(s):  
Muhammad Asad ◽  
Hassan Ijaz ◽  
Waqas Saleem ◽  
Abdullah Mahfouz ◽  
Zeshan Ahmad ◽  
...  

This contribution presents three-dimensional turning operation simulations exploiting the capabilities of finite element (FE) based software Abaqus/Explicit. Coupled temperature-displacement simulations for orthogonal cutting on an aerospace grade aluminum alloy AA2024-T351 with the conceived numerical model have been performed. Numerically computed results of cutting forces have been substantiated with the experimental data. Research work aims to contribute in comprehension of the end-burr formation process in orthogonal cutting. Multi-physical phenomena like crack propagation, evolution of shear zones (positive and negative), pivot-point appearance, thermal softening, etc., effecting burr formation for varying cutting parameters have been highlighted. Additionally, quantitative predictions of end burr lengths with foot type chip formation on the exit edge of the machined workpiece for various cutting parameters including cutting speed, feed rate, and tool rake angles have been made. Onwards, to investigate the influence of each cutting parameter on burr lengths and to find optimum values of cutting parameters statistical analyses using Taguchi’s design of experiment (DOE) technique and response surface methodology (RSM) have been performed. Investigations show that feed has a major impact, while cutting speed has the least impact in burr formation. Furthermore, it has been found that the early appearance of the pivot-point on the exit edge of the workpiece surface results in larger end-burr lengths. Results of statistical analyses have been successfully correlated with experimental findings in published literature.


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