Electrochemical micromachining of micro hole using micro drill with non-conductive mask on the machined surface

2020 ◽  
Vol 59 ◽  
pp. 366-377
Author(s):  
Hang Zou ◽  
Xiaoming Yue ◽  
Haixuan Luo ◽  
Baohui Liu ◽  
Shiyi Zhang
Author(s):  
Rajkeerthi E ◽  
Hariharan P

Abstract Surface integrity of micro components is a major concern particularly in manufacturing industries as most geometry of the products must meet out necessary surface quality requirements. Advanced machining process like electrochemical micro machining possess the capabilities to machine micro parts with best surface properties exempting them from secondary operations. In this research work, different electrolytes have been employed for producing micro holes in A286 super alloy material to achieve the best surface quality and the measurement of surface roughness and surface integrity to evaluate the machined surface is carried out. The machined micro hole provides detailed information on the geometrical features. A study of parametric analysis meant for controlling surface roughness and improvement of surface integrity has been made to find out the suitable parameters for machining. The suitability of various electrolytes with their dissolution mechanism and the influence of various electrolytes have been thoroughly studied. Among the utilized electrolytes, EG + NaNO3 electrolyte provided the best results in terms of overcut and average surface roughness.


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.


2008 ◽  
Vol 389-390 ◽  
pp. 375-380 ◽  
Author(s):  
Thai Nguyen ◽  
King Pang ◽  
Jun Wang

The erosion process in micro-machining of brittle glasses using a low pressure slurry jet is discussed. The process capability of the technique is assessed by examining the machined surface integrity in relation to fluid flow dynamics in micro-hole generations. The holes produced are characterised by a “W” shape in the cross section, while the surface morphology is distinguished by three zones associated with the fluid flow behaviour, i.e. a direct impact zone, a wavy zone and an accumulation zone. The surfaces appear to be smooth and without cracks, indicating a predominance of the ductile mode erosion process. With the increase of pressure, the erosion rates can be enhanced as a result of the expending of the accumulation zone while the outer diameter of the holes remains unchanged. This study shows that this technique can be used for micro-machining with high surface quality, and provides an essential understanding for further research in the avenue.


2021 ◽  
Author(s):  
Xu Wang ◽  
Valentin L. Popov ◽  
Zhanjiang Yu ◽  
Yiquan Li ◽  
Jingkai Xu ◽  
...  

Abstract In the micro cutting process of SiCp/Al composites, the tool wear is serious due to the existence of reinforcement phase in the material, which greatly affects the machined surface integrity. In order to reduce the friction and adhesion at the tool-chip interface, fabricating micro texture on the tool surface could be a feasible solution. This work focuses on the study of the cutting performance of the textured cutting tools through micro cutting of SiCp/Al composites. The experiments were carried out using NTK-KM1CCGW060202H uncoated cemented carbide tools with micro-hole textures developed by pulsed fiber laser. The results indicate that the micro-textured tools can reduce the wear, sticking and the contact length between the tool-chip. Also, the surface quality can be improved. It is observed from the chip’s surface that the micro-textured tool can produce secondary cutting when machining SiCp/Al composite materials, the smaller the texture spacing, the more obvious the secondary cutting phenomenon. Furthermore, the cutting forces can be reduced using the micro-textured tool in most cases. However, when the texture spacing is too small the cutting force does not decrease. Finally, the surface roughness and surface residual stress of the machined workpiece are investigated. Textured tools have better results.


Author(s):  
Mukesh Tak ◽  
Rakesh Mote

Abstract Titanium and its alloys are considered as difficult to cut material classes, and their processing through the traditional machining methods is a painful task. These materials have an outstanding combination of properties like high specific strength, excellent corrosive resistance, and exceptional bio-compatibility; therefore, they have broad fields of application like aerospace, MEMS, bio-medical, etc. Electrochemical micromachining (ECMM) is a very vital process for the production of micro-domain features in difficult-to-machine materials. The machining issue with ECMM for titanium and their alloys is the passive layer formation, which hinders the dissolution and causes stray removal. To overcome these issues, a hybrid ECMM approach has been proposed by using a diamond abrasive tool combined with ECMM. The present study focuses on the detailed characterization of the passive layer formed using the hybrid approach. Through the use abrasive tool, the abrasive grits scoop the passive layer by the mechanical grinding action, formed in micro-drilling on the Ti6Al4V alloy to expose a new surface for further dissolution. The micro-holes were produced incorporating the abrasive tool and then compared by the holes created using a cylindrical tool (tool without abrasive). The taper and the stray dissolution of the micro-holes were also compared, produced at different applied potentials. The minimum average entry overcut and exit overcut of the hole were obtained as 29 µm and 3 µm, respectively, also a micro-hole with the lowest taper of 2.7°, achieved by the use of the abrasive micro tool.


Author(s):  
G. Kibria ◽  
I. Shivakoti ◽  
B. Bhattacharyya

In micro-electrical discharge machining (micro-EDM), dielectric plays a significant role during the machining process as different types of dielectrics encounters different chemical compositions, cooling rates and dielectric strengths. Therefore, while employing these different dielectrics, dissimilar process responses are accounted when machining in EDM at micron level. The present paper investigates micro-EDM characteristics such as material removal rate (MRR), tool wear rate (TWR), overcut (OC), taperness and machining time (MT) during micro-machining of through holes on Ti-6Al-4V superalloy employing de-ionized water based dielectric other than conventional hydro-carbon oil i.e. kerosene. The paper also includes the comparative study of the micro-EDM machining characteristics employing boron carbide (B4C) powder as additive in de-ionized water dielectric at different discharge energies. The results show that MRR and taper of micro-hole are better and TWR is less employing B4C additive in the dielectric than pure one, i.e. the productivity is improved and same micro-tool can be used for machining an array of micro-holes. Surface topography and recast layer formed during micro-hole machining by micro-EDM has also been investigated based on optical and SEM micrographs. Energy dispersive spectroscopy (EDS) analysis of machined surface as well as tool electrode surface has been done and the results show that there is significant amount of infusion of tungsten element onto the machined surface. A significant amount of carbon element is found onto the tool electrode surface.


2010 ◽  
Vol 113-116 ◽  
pp. 1914-1917
Author(s):  
Ying Liu ◽  
Wei Liang Zeng ◽  
Zhen Long Wang

In the process of Electrochemical micromachining (EMM), the machining gap between tool cathode and workpiece anode is the root cause leading to the error, EMM error of Micro-hole array can be divided into duplication error and repeated error. According to the characteristics of EMM, the impact factors of micro-hole array duplication error and repeated error are analyzed. The distribution of electric field strength and scattered erosion are the most important causation resulting in duplication error. There is stray electric-field existing on electrode side, making scattered erosion to workpiece, impacting micro-hole forming processing precision, the extent of scattered erosion becomes serious with processing time growing, that is showed as phenomenon of sharp corner turning round and the phenomenon is observed carefully by experiments. While the accumulation of air bubbles in the processing region leads to the emergence of repeated error. Through theoretical and experimental analysis, measures are taked to improve machining accuracy.


CIRP Annals ◽  
2009 ◽  
Vol 58 (1) ◽  
pp. 177-180 ◽  
Author(s):  
D. Zhu ◽  
N.S. Qu ◽  
H.S. Li ◽  
Y.B. Zeng ◽  
D.L. Li ◽  
...  

2011 ◽  
Vol 464 ◽  
pp. 15-19 ◽  
Author(s):  
He Wang ◽  
Xue Li ◽  
Qi Ming Ju

An online monitoring method for micro-hole drilling based on rough sets fuzzy control is developed in this article to improve system on too many control rule numbers with strong subjectivity and complicated calculations. Utilize rough sets for reduction of fuzzy control rules and fuzzy control system for real time data processing of drilling capacity, drilling moment and spindle motor current under MATLAB platform. By discovering micro-drill bit abrasion information, online monitoring for micro drilling can be implemented in real time which can effectively prevent micro drill bit from crack.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
T. Praveena Gopinath ◽  
J. Prasanna ◽  
C. Chandrasekhara Sastry ◽  
Sandeep Patil

Abstract An attempt has been made to study the influence of magnetic field on the micro hole machining of Ti-6Al-4V titanium alloy using electrochemical micromachining (ECMM) process. The presence of magneto hydro dynamics (MHD) is accomplished with the aid of external magnetic field (neodymium magnets) in order to improve the machining accuracy and the performance characteristics of ECMM. Close to ideal solution for magnetic and nonmagnetic field ECMM process, the parameters used are as follows: concentration electrolyte of 15 g/l; peak current of 1.35 A; pulse on time of 400 s; and duty factor of 0.5. An improvement of 11.91–52.43% and 23.51–129.68% in material removal rate (MRR) and 6.03–21.47% and 18.32–33.09% in overcut (OC) is observed in ECMM of titanium alloy under the influence of attraction and repulsion magnetic field, respectively, in correlation with nonmagnetic field ECMM process. A 55.34% surface roughness factor reduction is ascertained in the hole profile in magnetic field-ECMM in correlation with electrochemical machined titanium alloy under nonmagnetic field environment. No machining related stress is induced in the titanium alloy, even though environment of electrochemical machining process has been enhanced with the presence of magnetic field. A slight surge in the compressive residual factor, aids in surge of passivation potential of titanium alloy, resulting in higher resistance to outside environment.


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