Elliptical Ultrasonic Assisted Grinding (EUAG) of Monocrystal Sapphire – Wear Behaviors of Resin Bond Diamond Wheel

2010 ◽  
Vol 126-128 ◽  
pp. 573-578 ◽  
Author(s):  
Yong Bo Wu ◽  
Zhi Qiang Liang ◽  
Xi Bin Wang ◽  
Wei Min Lin

This paper describes the wear behaviors of a resin bond diamond wheel in elliptical ultrasonic assisted grinding (EUAG) of monocrystal sapphire. The EUAG is a new grinding method proposed by the present authors in which an elliptical ultrasonic vibration is imposed on the workpiece by using an elliptical ultrasonic vibrator. In our previous work, an experimental apparatus mainly composed of the vibrator was produced and grinding experiments were conducted involving sapphire workpiece. In this paper, further investigations focusing on the wear behaviors of resin bond diamond wheel in EUAG of sapphire were carried out experimentally. The obtained results showed that: (1) the wheel wear process can be divided to three regions according to the variation trend of grinding forces, i.e., an initial region, a steady region, and a deteriorated region; (2) in the initial and steady regions, the grinding forces and the ratio of the normal grinding force to the tangential grinding force in EUAG are much smaller than that in conventional grinding (CG), but in deteriorated region, the grinding forces in EUAG are increased significantly up to be larger than that in CG whereas the grinding forces ratio has few difference between those in EUAG and CG; (3) in all the regions, the work-surface in EUAG is much smoother than that in CG whereas the wheel wear has little influence on the work-surface roughness; (4) the wheel wear in CG is mainly caused by the attrition wear and the macro-fracture and pullout of abrasive grains, while in EUAG by the micro-fracture and cleavage of abrasive grains.

2015 ◽  
Vol 9 (4) ◽  
pp. 365-372 ◽  
Author(s):  
Masakazu Fujimoto ◽  
◽  
Yongbo Wu ◽  
Mitsuyoshi Nomura ◽  
Hidenari Kanai ◽  
...  

This paper deals with the wear behavior of the mini-size diamond wheel used in Ultrasonic Assisted Grinding (UAG). The aim is to understand the wheel wear behavior. Sequential changes of the surface topography of the mini-size wheel, such as the number and shape of grains of the cutting edge, during the on-surface UAG process were observed and evaluated quantitatively using a Scanning Electron Microscope with four electron probes (3D-SEM). The obtained results show that a good wheel surface is maintained during the UAG process compared with the Conventional Grinding (CG) process. In particular, a number of sharp grain cutting edges are larger in the UAG process than those of the CG process. Additionally, these results are closely related to the stability of grinding forces and the reduction of the finished workpiece surface.


2013 ◽  
Vol 797 ◽  
pp. 356-361
Author(s):  
Wen Qing Song ◽  
Yong Bo Wu ◽  
Jian Guo Cao ◽  
Jing Ti Niu

Ultrasonic assisted grinding experiments were carried out to evaluate the effects of the ultrasonic vibration (UV) on the face grinding characteristics of nickel based superalloy of Rene77. In experiments, an electroplated cBN grinding wheel was ultrasonically vibrated dominantly along its axis. The experimental results indicated that the X-axis and Y-axis components of grinding forces with UV were smaller by 44.5% and 31.6%, respectively, than those without UV. The usual fractures and debris on the surface of workpiece disappeared and the work-surface roughness Ra was decreased by 42.3% once the UV was applied. The abrasion of the grinding wheel without UV is more serious than that with UV.


2014 ◽  
Vol 8 (4) ◽  
pp. 569-575 ◽  
Author(s):  
Masakazu Fujimoto ◽  
◽  
Yongbo Wu ◽  
Mitsuyoshi Nomura ◽  
Hidenari Kanai ◽  
...  

The objectives of this paper are to describe a quantitative evaluation of mini-size diamond grinding wheel surface topography in Ultrasonic Assisted Grinding (UAG) process and demonstrate the effects of topography on grinding characteristics. In this study, threedimensional (3D) analysis of the wheel working surface was observed using a Scanning Electron Microscope (SEM) with four electron probes (hereafter described as 3D-SEM) in an on-surface UAG process. These results indicated that a good wheel surface maintained in the UAG process is related to the number and the area of cutting edges. Additionally, the resulting topographic features of the grinding wheel surface are closely related to low grinding forces and allow easy manufacturing of a mirror workpiece surface.


2012 ◽  
Vol 565 ◽  
pp. 129-134 ◽  
Author(s):  
Kyeong Tae Kim ◽  
Yun Hyuck Hong ◽  
Kyung Hee Park ◽  
Young Jae Choi ◽  
Seok Woo Lee ◽  
...  

In this work, grinding test was performed in terms of machining parameters, such as grinding speed, feed rate, etc., in order to study effect of ultrasonic vibration in grinding. The design of experiment (DOE) approach was used for an optimal condition of ultrasonic assisted grinding, which can minimize the grinding forces. In DOE, ultrasonic amplitude power, feed rate, and rotation speed of spindle were chosen as the major machining factors. The grinding forces were measured and compared between the conventional grinding and ultrasonic assisted grinding. From the experiment, it was found that the grinding forces decreased as the ultrasonic vibration power and the rotation speed of spindle increased while the grinding force was reduced as the feed rate increased. In addition, regression model was formulated for obtaining optimal grinding condition.


Author(s):  
Ahmad Farhadi ◽  
Amir Abdullah ◽  
Javad Zarkoob ◽  
Abbas Pak

Ultrasonic assisted grinding of hard materials is a novel technique which is used in order to decrease grinding forces and energy. Grinding force is in direct connection with wheel wear, grinding accuracy, grinding temperature and surface integrity. In this paper the effects of ultrasonic vibration in creep feed grinding process which is superimposed to the workpiece in feed direction has been represented. The mechanism of grain-workpiece interaction in the presence of ultrasonic vibration has been investigated both analytically and numerically. The cutting path of a single grain in ultrasonic assisted grinding has been derived using equations of motion and has been compared to the grain cutting path in ordinary grinding. Using displacement equations of a single grain in ultrasonic assisted grinding and drawing the motion path, it has been shown that there exist a multiple-impact between grain and workpiece. By implementing a 2-D finite element modeling, the mechanism of chip formation in ultrasonic assisted grinding and ordinary grinding has been compared. Furthermore the effects of longitudinal workpiece vibration on the grinding forces have been investigated. FE analysis of grain-workpiece interaction in case of using ultrasonic vibration has shown a reduction of about 40% of grinding forces compared to ordinary grinding.


2012 ◽  
Vol 565 ◽  
pp. 135-141 ◽  
Author(s):  
Young Jae Choi ◽  
Kyung Hee Park ◽  
Yun Hyuck Hong ◽  
Kyeong Tae Kim ◽  
Seok Woo Lee ◽  
...  

In this paper, a ultrasonic horn, which can vibrate longitudinally with a frequency of 20㎑, was designed using finite element method (FEM). And the ultrasonic horn was fabricated for ultrasonic assisted grinding. To evaluate machining performance of the fabricated ultrasonic horn, grinding test was conducted on alumina ceramic (Al2O3). In the grinding test, grinding forces was measured and compared between the conventional grinding and the ultrasonic assisted grinding. The results showed that the grinding force in the ultrasonic grinding was lowered than the conventional grindign by 3~20%.


2012 ◽  
Vol 490-495 ◽  
pp. 2449-2453
Author(s):  
S.X. Yuan ◽  
M. Xiao

This paper analysis the mechanism of axial ultrasonic-assisted grinding(AUAG), by establishing the kinematics model of a single grit; The reason why AUAG forces are more lower than conventional grinding(CG) forces is presented, and the experiments of the grinding force in AUAG comparison with CG were carried out. The results indicate that the grinding force of the superalloy in AUAG is about 40% to 50% less than that in CG.


2003 ◽  
Vol 27 (3) ◽  
pp. 193-204 ◽  
Author(s):  
Andrew Warkentin ◽  
Robert Bauer

Grinding involves many randomly shaped and distributed abrasive grains removing material from a workpiece. Wheel wear results when these grains dull, fracture or break away. As a result, grinding forces are time-varying. In order to automate and optimize the grinding process an understanding of how forces are generated and change during grinding is critical to avoid workpiece damage, surface finish deterioration, cracking, excessive heat generation, and excessive residue stresses. This paper builds upon the existing grinding literature by studying the relationships between wheel wear and grinding forces for different depths of cut when surface grinding mild steel with an aluminum oxide wheel.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Zhang Jianhua ◽  
Zhao Yan ◽  
Zhang Shuo ◽  
Tian Fuqiang ◽  
Guo Lanshen ◽  
...  

Ultrasonic vibration assisted micro end grinding (UAMEG) is a promising processing method for micro parts made of hard and brittle materials. First, the influence of ultrasonic assistance on the mechanism of this processing technology is theoretically analyzed. Then, in order to reveal the effects of ultrasonic vibration and grinding parameters on grinding forces and surface quality, contrast grinding tests of silica glass with and without ultrasonic assistance using micro radial electroplated diamond wheel are conducted. The grinding forces are measured using a three-component dynamometer. The surface characteristics are detected using the scanning electron microscope. The experiment results demonstrate that grinding forces are significantly reduced by introducing ultrasonic vibration into conventional micro end grinding (CMEG) of silica glass; ultrasonic assistance causes inhibiting effect on variation percentages of tangential grinding force with grinding parameters; ductile machining is easier to be achieved and surface quality is obviously improved due to ultrasonic assistance in UAMEG. Therefore, larger grinding depth and feed rate adopted in UAMEG can lead to the improvement of removal rate and machining efficiency compared with CMEG.


2014 ◽  
Vol 620 ◽  
pp. 128-133 ◽  
Author(s):  
Kai Ding ◽  
Yu Can Fu ◽  
Hong Hua Su ◽  
Tao He ◽  
Xi Zhai Yu ◽  
...  

In the present work, ultrasonic assisted grinding (UAG) and conventional grinding (CG, without ultrasonic) tests of Carbon fiber reinforced silicon carbide matrix (C/SiC) composites were conducted. In addition, analysis was done by comparing the machining quality, grinding force, and specific grinding energy between the two processes. The results showed that material removal mode of carbon fiber both in CG and UAG were brittle fracture, and fracture size had no obvious difference. Compared with CG, brittle fracture area of SiC increased during UAG. In comparison with CG, the normal grinding force and tangential grinding force for UAG were reduced maximally by 45%, 39% respectively of those for CG. Accordingly, specific grinding energy was also reduced by UAG. Therefore, UAG can improve the grinding performance of C/SiC composites significantly.


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