Micro Ultrasonic Machining Using Oil Based Abrasive Slurry

Author(s):  
Murali M. Sundaram ◽  
Sreenidhi Cherku ◽  
K. P. Rajurkar

Advanced engineering materials posses excellent properties such as high wear resistance, and inertness to corrosion and chemical reactions. Since these materials are usually hard, brittle, chemically inert, and electrically nonconductive, they pose serious machinability challenges. Micro ultrasonic machining (Micro USM) is an emerging method for the micromachining of hard and brittle materials without any thermal damage. This paper presents the results of micro ultrasonic machining using oil based abrasive slurry. Details of the in-house built experimental setup used to conduct the experiments are explained. The influence of process parameters such as slurry medium, slurry concentration, and abrasive particle size on the performance of micro USM are reported. It was noticed that the evidence of three body material removal mechanism is predominant for micro USM using oil based slurry. In general, the material removal rate increases with the increase in the abrasive particle size for both aqueous abrasive slurry and oil based abrasive slurry. Further, material removal rate is consistently higher for experiments conducted with aqueous abrasive slurry medium. On the other hand, it is noticed that the oil based slurry medium provides better surface finish. It is also noticed that the smaller abrasive grains provide better surface finish for both aqueous, and oil based abrasive slurry mediums. Role of slurry concentration is ambiguous, as no clear trend of its effect of on process performance is evident in the available experimental results.

2001 ◽  
Vol 671 ◽  
Author(s):  
Chunhong Zhou ◽  
Lei Shan ◽  
S.H. Ng ◽  
Robert Hight ◽  
Andrew. J. Paszkowski ◽  
...  

ABSTRACTThis paper reports on the effect of colloidal abrasive particle size in the polishing of thermally grown silicon dioxide on 100mm diameter, P-type, (100), single crystal silicon wafers. The abrasive particle sizes were varied in six (6) slurries with pH values of 10.97 ± 0.08. The abrasive sizes were 10, 20, 50, 80, 110 and 140nm in diameter, and the slurry contained 30 weight percent abrasives. The experimental results indicate that the material removal rate (MRR) varies with the volume of the particle size. Results also confirm that there exists an optimum abrasive particle size with respect to material removal rate and surface finish. For a pad surface roughness of 5.2μm (Ra), the slurry containing 80nm particles resulted in the highest material removal rate and best surface finish. A nano-film model based on the pad roughness is used to explain the results.


1995 ◽  
Vol 21 (5) ◽  
pp. 355-366 ◽  
Author(s):  
T.A. Stolarski ◽  
E. Jisheng ◽  
D.T. Gawne ◽  
S. Panesar

1995 ◽  
Vol 117 (2) ◽  
pp. 142-151 ◽  
Author(s):  
Z. J. Pei ◽  
D. Prabhakar ◽  
P. M. Ferreira ◽  
M. Haselkorn

An approach to modeling the material removal rate (MRR) during rotary ultrasonic machining (RUM) of ceramics is proposed and applied to predicting the MRR for the case of magnesia stabilized zirconia. The model, a first attempt at predicting the MRR in RUM, is based on the assumption that brittle fracture is the primary mechanism of material removal. To justify this assumption, a model parameter (which models the ratio of the fractured volume to the indented volume of a single diamond particle) is shown to be invariant for most machining conditions. The model is mechanistic in the sense that this parameter can be observed experimentally from a few experiments for a particular material and then used in prediction of MRR over a wide range of process parameters. This is demonstrated for magnesia stabilized zirconia, where very good predictions are obtained using an estimate of this single parameter. On the basis of this model, relations between the material removal rate and the controllable machining parameters are deduced. These relationships agree well with the trends observed by experimental observations made by other investigators.


Author(s):  
Hariharan Perianna Pillai ◽  
Shamli Chinnakulanthai Sampath ◽  
Rajkeerthi Elumalai ◽  
Shruthilaya Hariharan ◽  
Yuvaraj Natarajan

Electrochemical micromachining process is one among the successful micromachining technique, which uses the electrochemical energy and is recognized for machining difficult-to-cut materials. One such material is Nimonic 75 alloy, which is used to make gas turbine components. In this study, an effort has been made to machine micro-hole profiles in Nimonic 75 with a thickness of 500 μm using two different electrolytes. A combination of sodium bromide, hydrofluoric acid and ethylene glycol has been chosen as the first electrolyte, while the second is a combination of sodium chloride and sodium nitrate. Solid tungsten carbide of diameter 500 μm is used as the tool in each case. For layout of experiments, Taguchi orthogonal array was chosen with following input parameters namely voltage, micro-tool feed rate and duty cycle. Performance characteristics such as material removal rate, overcut and conicity have been assessed for each electrolyte. Experimental results have shown that the first electrolyte yields lower values of overcut (OC) and conicity, whereas the second electrolyte gives higher material removal rate (MRR). Further, the optimal combinations of process parameters have been found by implementing the TOPSIS procedure and the results were found to be in good agreement with the experimental outcomes.


Author(s):  
VG Ladeesh ◽  
R Manu

The electrically non-conductive materials like glass, ceramics, quartz, etc. are of great interest for many applications in modern industries. Machining them with high quality and at a faster rate is a challenging task. In this study, a novel technique called grinding aided electrochemical discharge drilling (G-ECDD) is demonstrated which uses a hollow diamond core drill as the tool for performing electrochemical discharge machining of borosilicate glass. The new hybrid technique enhances the material removal rate and machining accuracy to several folds by combining the thermal melting action of discharges and grinding action of the abrasive tool. This paper presents the experimental investigation on the material removal rate during G-ECDD of glass while using different electrolytes. An attempt has been made to explore the influence of electrolyte temperature on G-ECDD performance by maintaining the electrolyte at different temperatures. Experiments were conducted using three different electrolytes which include NaOH, KOH, and the mixture of both. The results obtained from this study revealed that an increase in temperature will favor chemical etching as well as electrochemical reaction rate. Also, it was observed that heating the electrolyte leads to an increase in the bubble density and enhances the ion mobility. This causes the formation of gas film at a faster rate and thereby improving the discharge activity. Thus, machining will be done at a faster rate. Better results are obtained while using a mixture of NaOH and KOH. From the microscopic images of the machined surface, it was observed that material removal mechanism in G-ECDD is a combination of grinding action, electrochemical discharges, and chemical etching. Response surface methodology was adopted for studying the influence of process parameters on the performance of G-ECDD. The new technique of grinding aided electrochemical discharge drilling proved its potential to machine borosilicate glass and simultaneously offers good material removal rate, repeatability, and accuracy.


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