High Efficient Mechanism of Material Removal in Two-Dimensional Ultrasonic Grinding from the Locus Perspective

2009 ◽  
Vol 416 ◽  
pp. 609-613
Author(s):  
Ming Li Zhao ◽  
Bo Zhao ◽  
Yu Qing Wang ◽  
Guo Fu Gao

Relative motion of single abrasive is analyzed for the different applied directions of longitudinal ultrasonic vibration, and its locus is simulated in the present paper. The research results show that the locus in two-dimensional ultrasonic vibration is only similar to that in y-direction, and both are close to sinusoid curves. The width of grooves scratched by abrasive grains y-direction (axial direction of grinding wheel) is two times of the vibration amplitude, and the material removal rate increases remarkably. In case of x-direction (tangential direction of grinding wheel) ultrasonic vibration, abrasive grains with periodic force impact material surface with high frequency vibration, which make material fracture removal easy. Therefore, the high efficiency essence of material removal in two-dimensional ultrasonic grinding is revealed in view of locus. In addition, according to the results of grinding experiments, under same conditions good surface quality can be obtained in two-dimensional ultrasonic grinding and material removal rate in common grinding is the lowest. Consequently it is further proved that the method of two-dimensional ultrasonic vibration grinding is an effective one for ceramic materials.

2007 ◽  
Vol 359-360 ◽  
pp. 431-435
Author(s):  
Guo Fu Gao ◽  
Bo Zhao ◽  
Qing Hua Kong ◽  
Chuan Shao Liu

Based on the machining pattern, mechanics of material removal and theory of micro-indentation, in previous studies the models of material removal rate of hard-brittle materials was discussed through the relatively influencing factors of machining parameters from various aspects, reflecting the research advances on mechanics of material removal of hard-brittle materials. However, those models of material removal rate have limitations, which results from impercipient theory of fracture of new kinks of materials, randomicity of practical machining process, inappropriate assumptions and simplification of the machining conditions and so on. In this work firstly, previous models of material removal rate of hard-brittle materials machining with ultrasonic assistance were reviewed briefly. Subsequently, the models of material removal rate of complex ceramics machining with two-dimensional ultrasonic vibration assistance were established based on fracture theory of micro- indentation in fracture regime and plastic removal mechanics in ductile regime respectively. The material removal rate is affected not only by the properties of material and machining parameters, but also by the character of grinding wheel and parameters of ultrasonic vibration.


2007 ◽  
Vol 329 ◽  
pp. 451-458 ◽  
Author(s):  
Yan Wu ◽  
A.G. Sun ◽  
Bo Zhao ◽  
Xun Sheng Zhu

Based on the single abrasive particle motion locus of elliptical spiral in two-dimensional ultrasonic vibration grinding (WTDUVG), the theoretical model representing the material removal rate are deduced and verified, and the reason of high efficiency material removal by applying two-dimensional ultrasonic vibration is analyzed. Finally, experimental researches on material removal rate of ceramics were carried out using coarse grit diamond wheel both with and without workpiece two-dimensional ultrasonic vibration assistance grinding. Experimental results indicated that (1) Material removal rate (MRR) in vibration grinding process is about 1.5 times as large as that of in conventional grinding, the experimental results are in good agreement with the calculated ones. (2)The material removal rate increases along with increases of the grinding depth and workpiece velocity both in with and without vibration grinding. (3)The vibration grinding surface had no spur and build-up edge and its surface roughness was smaller than CG significantly. Surface quality of WTDUVG is superior to that of conventional grinding, it is easy for ultrasonic vibration grinding that material removal mechanism is ductile regime grinding.


Author(s):  
Gurpreet Singh ◽  
DR Prajapati ◽  
PS Satsangi

The micro-electrical discharge machining process is hindered by low material removal rate and low surface quality, which bound its capability. The assistance of ultrasonic vibration and magnetic pulling force in micro-electrical discharge machining helps to overcome this limitation and increase the stability of the machining process. In the present research, an attempt has been made on Taguchi based GRA optimization for µEDM assisted with ultrasonic vibration and magnetic pulling force while µEDM of SKD-5 die steel with the tubular copper electrode. The process parameters such as ultrasonic vibration, magnetic pulling force, tool rotation, energy and feed rate have been chosen as process variables. Material removal rate and taper of the feature have been selected as response measures. From the experimental study, it has been found that response output measures have been significantly improved by 18% as compared to non assisted µEDM. The best optimal combination of input parameters for improved performance measures were recorded as machining with ultrasonic vibration (U1), 0.25 kgf of magnetic pulling force (M1), 600 rpm of tool rotation (R2), 3.38 mJ of energy (E3) and 1.5 mm/min of Tool feed rate (F3). The confirmation trail was also carried out for the validation of the results attained by Grey Relational Analysis and confirmed that there is a substantial improvement with both assistance applied simultaneously.


2008 ◽  
Vol 53-54 ◽  
pp. 155-160 ◽  
Author(s):  
Qiu Sheng Yan ◽  
Ai Jun Tang ◽  
Jia Bin Lu ◽  
Wei Qiang Gao

A new plate polishing technique with an instantaneous tiny-grinding wheel cluster based on the magnetorheological (MR) effect is presented in this paper, and some experiments were conducted to prove its effectiveness and applicability. Under certain experimental condition, the material removal rate was improved by a factor of 20.84% as compared with the conventional polishing methods with dissociative abrasive particles, while the surface roughness of the workpiece was not obviously increased. Furthermore, the composite of the MR fluid was optimized to obtain the best polishing performance. On the basis of the experimental results, the material removal model of the new plate polishing technique was presented.


2010 ◽  
Vol 447-448 ◽  
pp. 193-197
Author(s):  
Wei Qiang Gao ◽  
Qiu Sheng Yan ◽  
Yi Liu ◽  
Jia Bin Lu ◽  
Ling Ye Kong

Electro-magneto-rheological (EMR) fluids, which exhibit Newtonian behavior in the absence of a magnetic field, are abruptly transformed within milliseconds into a Bingham plastic under an applied magnetic field, called the EMR effect. Based on this effect, the particle-dispersed EMR fluid is used as a special instantaneous bond to cohere abrasive particles and magnetic particles together so as to form a dynamical, flexible tiny-grinding wheel to machine micro-groove on the surface of optical glass. Experiments were conducted to reveal the effects of process parameters, such as the feed rate of the horizontal worktable, feeding of the Z axis, machining time and machining gap, on material removal rate of glass. The results indicate that the feed rate of the worktable at horizontal direction has less effect on material removal rate, which shows a fluctuation phenomenon within a certain range. The feed rate of the Z axis directly influences the machining gap and leads to a remarkable change on material removal rate. Larger material removal rate can be obtained when the feeding frequency of Z direction is one time per processing. With the increase of rotation speed of the tool, material removal rate increases firstly and decreases afterwards, and it gets the maximum value with the rotation speed of 4800 rev/min. The machining time is directly proportional to material removal amount, but inversely proportional to material removal rate. Furthermore, material removal rate decreases with the increase of the machining gap between the tool and the workpiece. On the basis of above, the machining mode with the tiny-grinding wheel based on the EMR effect is presented.


2006 ◽  
Vol 304-305 ◽  
pp. 555-559 ◽  
Author(s):  
Chang He Li ◽  
Guang Qi Cai ◽  
Shi Chao Xiu ◽  
Q. Li

The material removal rate (MRR) model was investigated in abrasive jet precision finishing (AJPF) with wheel as restraint. When abrasive wore and workpiece surface micro-protrusion removed, the size ratio for characteristic particle size to minimum film thickness gradually diminishing, the abrasive machining from two-body lapping to three-body polishing transition in AJPF with grinding wheel as restraint. In the study, the material removal rate model was established according to machining mechanisms and machining modes from two-body to three-body process transition condition, and active number of particles in grinding zone were calculated and simulated. Experiments were performed in the plane grinder for material removal mechanism and academic models verification. It can be observed from experimental results that the surface morphology change dramatically to a grooved or micro-machined surface with all the grooves aligned in the sliding direction in two-body lapping mode. On the other hand, the surface is very different, consists of a random machining pits with very little sign of any directionality to the deformation in the three-body machining mode. Furthermore, the material removal rate model was found to give a good description of the experimental results.


2008 ◽  
Vol 53-54 ◽  
pp. 243-247 ◽  
Author(s):  
Bo Zhao ◽  
Ming Li Zhao ◽  
Guo Fu Gao

The influence of ultrasonic vibration on the surface roughness and micro-topography of ceramics plate is discussed in this paper. Grinding assisted by two-dimensional ultrasonic vibration is developed to deal with the processing difficulty of ceramic materials due to its hard-brittle property. The experimental results show that the surface roughness value obtained in two-dimensional ultrasonic grinding nano-ZrO2 ceramic plate specimen is obviously smaller than that in common grinding, and the scratched grooves on the machined surface in ultrasonic grinding is wider and relatively smoother than that in common grinding. Consequently, it proves that the two-dimensional ultrasonic machining is a feasible, high-efficient machining method for hard-brittle materials.


Author(s):  
Kishore S. Gaikwad ◽  
Suhas S. Joshi

Microelectrochemical grinding (micro-ECG) is a variant of electrochemical grinding (ECG) process, in which material is removed by a combination of electrolytic dissolution and abrasive action that take place in a small interelectrode gap. This paper discusses analytical modeling of the material removal phenomenon in micro-ECG process to predict material removal rate. In the model, the phenomena, which contribute to the material removal in the process by electrolytic and abrasive actions, have been considered; these include streaming potential in the electrochemical action and shearing forces due to the flow of electrolyte through interelectrode gap and the abrasive action of grinding wheel. Two configurations of the process, viz., surface and cylindrical micro-ECG, have been modeled. The results have been validated by CFD simulation in the case of surface micro-ECG process, and specific experimentation in the case of cylindrical micro-ECG process.


2010 ◽  
Vol 154-155 ◽  
pp. 1604-1613
Author(s):  
Mohammad Reza Shabgard ◽  
Babak Sadizadeh ◽  
Keivan Amini ◽  
Hamid Pourziaie

The correct selection of the machining parameters is one of the most significant issues to take into consideration in Ultrasonic-assisted Electrical Discharge Machining (US-EDM) and EDM processes. In the present work, a study has been made to develop and extract statistical models to show the relationship between important machining performance data (material removal rate (MRR), tool wear ratio (TWR) and surface roughness Ra) and the input machining parameters (pulse current, and pulse-on time) in the EDM and US-EDM of AISI H13. The models obtained were used to analyze the effects of input parameters on machining performance. In addition, a comparative study was carried out to investigate the effect of ultrasonic vibration of the workpiece on machining performance. The results show that Ultrasonic vibration of the workpiece can significantly reduce the inactive pulses and improves the stability of process. Also US-EDM is effective in attaining a high material removal rate (MRR) in finishing regime in comparison with conventional EDM. The results of Analysis of Variance (ANOVA) indicate that the proposed mathematical models can adequately explain the performance within the limits of the factors being studied.


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