Modeling of the Effect of Machining Parameters on Maximum Thickness of Cut in Ultrasonic Elliptical Vibration Cutting

Author(s):  
Chandra Nath ◽  
Mustafizur Rahman ◽  
Ken Soon Neo

In recent years, the ultrasonic elliptical vibration cutting (UEVC) technique has been found to be an efficient method for the ultraprecision machining of hard and brittle materials. During the machining at a given nominal depth of cut (DOC), the UEVC technique, because of its inherent mechanism, effectively reduces the thickness of cut (TOC) of the workpiece material through overlapping vibration cycles. For the ductile machining of hard and brittle materials, this TOC plays a critical role. However, the relationships between the nominal DOC, the TOC, and the relevant machining parameters have not yet been studied. In this study, the role playing machining parameters for the TOC are firstly investigated and then theoretical relations are developed for predicting the maximum TOC (TOCm) with respect to the relevant machining parameters. It is found that four machining parameters, namely, workpiece cutting speed, tool vibration frequency, and tangential and thrust directional vibration amplitudes, influence the TOCm. If the speed ratio (ratio of the workpiece cutting speed to the maximum tool vibration speed in the tangential direction) is within a critical value 0.12837, then a reduced TOCm can be obtained. It is also realized that if the TOCm can be kept lower than the critical DOC (DOCcr), then ductile finishing of brittle materials can be achieved. The above phenomenon has been substantiated by experimental findings while machining a hard and brittle material, sintered tungsten carbide. The findings suggest that the same concept can be applied for the ductile cutting of other hard and brittle materials.

Author(s):  
Sen Yin ◽  
Zhigang Dong ◽  
Yan Bao ◽  
Renke Kang ◽  
Wenhao Du ◽  
...  

Abstract Ultrasonic elliptical vibration cutting (UEVC) technique, as an advanced cutting method, has been successfully applied to machine difficult-to-cut materials for the last decade. In this study, the mechanism of the elliptical vibration locus caused by the “asymmetric structure” of the horn was analyzed theoretically firstly, and the corresponding relationship between the degree of asymmetry and the elliptical vibration locus was determined based on finite element method (FEM). Then an efficient single-excitation UEVC device with “asymmetric structure” was developed and optimized. The resonant frequency of the device was 40.8 kHz, and the amplitude reached 12.4 µm, which effectively broke the limitation of cutting speed in UEVC. Finally, the UEVC device's performance was tested, and the advantages in improving the tungsten alloy surface quality and reducing diamond cutting tool wear validated the technical capability and principle of the proposed device.


2011 ◽  
Vol 314-316 ◽  
pp. 1851-1856 ◽  
Author(s):  
Xin Quan Zhang ◽  
A. Senthil Kumar ◽  
Mustafizur Rahman

The elliptical vibration cutting (EVC) technique has been found to be a promising technique for ultraprecision machining of various materials. Researchers have proved that the EVC technique prevails over both conventional cutting and 1D vibration cutting techniques in most aspects in terms of cutting performances. However, during the EVC process, vibration marks or cusps are generated by the elliptical vibration locus and can result in an increase in the overall roughness of machined surface, which is undesirable for achieving high-quality mirror surface. Although researchers have developed a calculation method for the height of the cusps, only the effects of vibration frequency on surface generation were studied, and the effects of the other vibration and machining parameters have not been investigated in detail by previous researchers. Hence, in the present study, in order to deeply understand surface generation process along nominal cutting direction under the EVC technique, which is critical for its performance improvement and application, an experimental study comprising a series of grooving tests was carried out. The effects of nominal cutting speed on the surface generation at two different thrust-directional vibration amplitudes are investigated. Analysis is given for the comparison between the theoretical and experimental roughness values, showing that there exists a critical nominal cutting speed, below which the measured roughness value is quite small and the vibration marks are almost undetectable.


2009 ◽  
Vol 69-70 ◽  
pp. 133-137 ◽  
Author(s):  
Eiji Shamoto ◽  
Norikazu Suzuki

Precision machining, named ‘elliptical vibration cutting’, and its application to ultraprecision / micro machining of some hard / brittle materials are introduced in the present paper. The elliptical vibration cutting has a superior cutting performance in terms of low cutting force, low cutting energy, low heat generation, long tool life for steels, sintered tungsten alloy, etc., and large critical depth of cut for ductile machining of brittle materials such as glasses and single crystal calcium fluoride, etc. Based on these basic advantages, practical ultraprecision / micro machining of the hard / brittle materials is successfully realized by employing the ultrasonic elliptical vibration tools, which have been developed for ultraprecision machining.


Author(s):  
Wu-Le Zhu ◽  
Yu He ◽  
Kornel F. Ehmann ◽  
Antonio J. Sánchez Egea ◽  
Xinwei Wang ◽  
...  

Alumina (Al2O3) is an extremely hard and brittle ceramic that is usually used as an abrasive or a cutting tool insert in manufacturing. However, its growing applications in industrial products make it necessary to conduct a study of the machinability of alumina themselves with a cost-effective and flexible method, rather than conventional diamond grinding or laser-assisted processing methods. In this paper, polycrystalline diamond tools are used to investigate the machining of nonporous pure alumina by applying an inclined ultrasonic elliptical vibration cutting (IUEVC) method. First, a theoretical analysis is presented to study the effects of the machining parameters on cutting performances during raster cutting procedures from the prospective of the material removal rate (MRR), tool-chip contact area, cutting edge angle, etc. Then, experiments are carried out to investigate the cutting forces and the areal surface roughness (Sa) in connection with the theoretically established relationships. The results show that the cutting forces are remarkably reduced, by up to more than 90%, and that the machined surface finish is also improved compared with conventional methods.


2011 ◽  
Vol 55-57 ◽  
pp. 327-331 ◽  
Author(s):  
Cheng Mao Zhang ◽  
Cheng Li ◽  
De Yuan Zhang

Hardened stainless steels are materials widely used in the field of aviation and spaceflight. Machining of this materials with conventional cutting (CC) method is a real challenge compared to other difficult-to-cut materials. Ultrasonic elliptical vibration cutting (UEVC) method is a novel and non-conventional cutting technique which has been successfully applied to machine such intractable materials for the last decade. However, few studies have been conducted on the cutting force in ultrasonic elliptical vibration cutting of hardened materials. This paper presents an experimental study on cutting force in UEVC of hardened stainless steels using cemented carbide tools. Experiments have been carried out to investigate the effect of cutting parameters in the UEVC method in terms of cutting force, while cutting hardened stainless steels. The tests have revealed that the average thrust force,principal force and feed force drop to 3%,10% and 90% of CC value for UEVC of hardened stainless steels. The ratio between the CC force and the UEVC force decrease with the increase of DOC and cutting speed.


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