Anodic Dissolution Behaviour of Passive Layer During Hybrid Electrochemical Micromachining of Ti6Al4V in NaNO3 Solution

2021 ◽  
Author(s):  
Mukesh Tak ◽  
Rakesh Mote
Keyword(s):  
Hybrid Approach ◽  
Passive Layer ◽  
Electrochemical Micromachining ◽  
Abrasive Tool ◽  
Specific Strength ◽  
Micro Holes ◽  
Micro Drilling ◽  
Micro Hole ◽  
Micro Tool ◽  
Bio Compatibility

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.

Influence of Process Parameters on Electrochemical Micromachining of Nimonic 75 Alloy

2017 ◽  
Author(s):  
Hariharan Perianna Pillai ◽  
Shamli Chinnakulanthai Sampath ◽  
Rajkeerthi Elumalai ◽  
Shruthilaya Hariharan ◽  
Yuvaraj Natarajan
Keyword(s):  
Process Parameters ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Cycle Performance ◽  
Electrochemical Micromachining ◽  
Influence Of Process Parameters ◽  
Micro Hole ◽  
Micro Tool ◽  
Nimonic 75

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.

The tool-wear characteristics of flexible printed circuit board micro-drilling and its influence on micro-hole quality

Circuit World ◽  
2016 ◽  
Vol 42 (4) ◽  
pp. 162-169 ◽  
Author(s):  
Lijuan Zheng ◽  
Chengyong Wang ◽  
Xin Zhang ◽  
Xin Huang ◽  
Yuexian Song ◽  
...  
Keyword(s):  
Tool Wear ◽  
Circuit Board ◽  
Hole Quality ◽  
Content Type ◽  
Wear Characteristics ◽  
Printed Circuit ◽  
Micro Holes ◽  
Micro Drilling ◽  
Micro Hole

Purpose Micro-holes are drilled and plated in flexible printed circuit boards (FPCs) for connecting circuits from different layers. More holes, with diameters smaller than 0.3 mm, are required to be drilled in smaller areas with flexible circuits’ miniaturization. The micro-hole quality of micro-drilling is one of the biggest issues of the flexible circuit manufacturers’ production. However, it is not easy to control the quality of micro-holes. The purpose of this study was to conduct research on the tool wear characteristics of FPC drilling process and its influence on micro-hole quality to improve the micro-hole quality of FPC. Design/methodology/approach The tool-wear characteristics of micro-drills after FPC drilling were observed. The influence of spindle speed, feed rate, number of drilled holes and entry board materials on tool-wear was analyzed. The hole qualities of FPC micro-drilling were measured and observed. The relationship between tool-wear and hole quality was analyzed. Findings The result showed that the tool-wear characteristics of FPC micro-drilling was similar to the tool-wear characteristics of rigid printed circuit board (RPC) micro-drilling. Abrasive wear occurred on both the main cutting edges and the chisel edges of micro-drills, even though there was no glass fiber reinforcing the cloth inside FPC. Resin adhesion was observed on the chisel edge. The influence of feed and number of drilled holes on tool-wear was significant. Tool-wear significantly influences the hole quality of FPC. Tool-wear will largely decrease the hole position accuracy of FPC micro-holes. Tool-wear will increase the thickness of PI nail heads and the height of exit burrs. Fracture was the main difference between tool wear of FPC and RPC micro-drilling. Resin adhesion of RPC was much more severe than FPC micro-drilling. Increasing the spindle speed properly may improve tool life and hole quality. Originality/value The technology and manufacturing of FPC has been little investigated. Research on micro-drilling FPC and research data is lacking so far. The micro-hole quality directly affects the reliability of FPC. Thus, improving the micro-hole quality of FPC is very important.

Development of Tool Electrode High Frequency Vibration Assisted Micro-Hole EDM Machine for Industry Environment

2010 ◽  
Vol 44-47 ◽  
pp. 430-435
Author(s):  
Ming Gang Xu ◽  
Xue Ke Luo ◽  
Yong Li
Keyword(s):  
High Frequency ◽  
Main Body ◽  
Tool Electrode ◽  
High Frequency Vibration ◽  
Electrical Control ◽  
Industry Environment ◽  
Micro Holes ◽  
Micro Hole ◽  
Micro Tool ◽  
Series Of Experiments

A new tool electrode high frequency vibration assisted micro-hole EDM machine tool aimed to resolve the problem of machine large quantities micro holes in industry was designed. The machine is mainly composed of main body, electrical control module and assistant mechanisms etc. And drawn tungsten wire was used as the micro tool electrode. A series of experiments were carried out using the micro-hole EDM machine.

Influence of the Planetary Movement of Tool on the Aspect Ratio of Micro Holes Machined by Micro-Ultrasonic Machining

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Senwang Lei ◽  
Zuyuan Yu ◽  
Kai Zhou ◽  
Jianzhong Li ◽  
Renke Kang
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Ultrasonic Machining ◽  
Processing Efficiency ◽  
Machining Speed ◽  
Micro Holes ◽  
Hard And Brittle Materials ◽  
Micro Hole ◽  
Micro Tool ◽  
Movement Parameters

The micro-ultrasonic machining (USM) is suitable for machining hard and brittle materials. When a micro hole is drilled deeply using micro-USM, machining speed slows down and the breakage of micro tool may occur. To solve this problem, this paper proposes the application the planetary movement of micro tool in high-aspect ratio micro holes drilling by micro-USM. The micro holes of about 92 μm in diameter with an aspect ratio larger than ten have been machined. The processing efficiency has been improved. The influence of planetary movement parameters on processing efficiency has been investigated

Multicharacteristics optimization of electrical discharge micro hole drilling in Mg alloy using hybrid approach of GRA–regression–PSO

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Neeraj Ahuja ◽  
Uma Batra ◽  
Kamal Kumar
Keyword(s):  
Hybrid Approach ◽  
Mg Alloy ◽  
Hole Drilling ◽  
Bone Implants ◽  
Content Type ◽  
Response Characteristics ◽  
Micro Holes ◽  
Micro Hole ◽  
Experimental Values ◽  
Grey Relational

PurposeMagnesium alloys are becoming prominent as an alternative to the permanent biomedical implants. In present work, electric discharge drilling (EDD) process has been investigated and optimized for ZM21 Mg alloy that can be used for producing perforated bone implants having geometrically precise micro holes.Design/methodology/approachPlanning of experiments has been carried out in accordance to the Taguchi mixed L18 orthogonal array (OA). The hole overcut (HO), circularity at entrance (Cent) and circularity at exit (Cext) of drilled micro holes were measured as response characteristics during experimentation corresponding to different settings of EDD input parameters. For optimizing multiresponse characteristics, the hybrid approach of grey relational analysis, regression analysis and particle swarm optimization has been implemented.FindingsIt is found from hybrid approach that brass electrode along with Ip; 3 Amp, Ton; 50 µs and Toff; 52 µs outperformed over all other parametric settings against the collective result of response characteristics. The experimental values of response characteristics at suggested optimized setting are HO: 93.48 µm; Cent: 0.988 and Cext: 0.992, respectively.Originality/valueThe optimization of EDD process for developing perforated Mg alloy bone implants, using hybrid approach is still missing.

Mechanical drilling of PCB micro hole and its application in micro ultrasonic powder molding

Circuit World ◽  
2015 ◽  
Vol 41 (2) ◽  
pp. 87-94 ◽  
Author(s):  
Xiong Liang ◽  
Bing Li ◽  
Lianyu Fu ◽  
Xiaoyu Wu ◽  
Hongyan Shi ◽  
...  
Keyword(s):  
Cylinder Surface ◽  
Average Particle ◽  
Drilling Process ◽  
Content Type ◽  
Cylinder Array ◽  
Micro Holes ◽  
Micro Drilling ◽  
Micro Hole ◽  
Hole Arrays ◽  
Micro Cavity

Purpose – This paper aims to present the main factors affecting the mechanical drilling of the printed circuit board (PCB for short) micro-holes and method of micro-ultrasonic powder molding (micro-UPM for short) by utilizing PCB micro-hole array. Design/methodology/approach – To optimize the drilling process, the paper proposes the on-line monitoring methods for the drilling process including drilling force, drilling temperature, high-speed photography and vibration signals. Taking 0.10 and 0.15 mm micro-drilling as examples, the paper analyzes the drilling process of ultra-small micro-holes. Finally, by taking the PCBs with 0.10 and 0.15 mm micro-hole arrays as the micro-cavity inserts, utilizing ultra-high-molecule weight polyethylene powder with the average particle size of about 150 μm as raw material, two sizes of micro-cylinder array polymer parts are fabricated through micro-UPM process. Findings – PCB micro-cavity inserts with micro-hole arrays fabricated by mechanical drilling has the advantages of low costs, high efficiency and good consistency. Taking 0.10 and 0.15 mm micro-drilling as examples, it is found that the both measured apertures are about 10.0 μm more than the diameter of the micro-drill bits on average. The average diameter of the micro-cylinders by micro-UPM process is smaller than that of the micro-hole with the same specification, while the value of the roughness of the cylinder surface is more than that of the hole-wall surface with the same specification. Originality/value – This paper describes the challenges and the developments of mechanical drilling and by using PCB micro-cavity inserts with micro-hole arrays fabricated by mechanical drilling, two different micro-cylinder array polymer parts are successfully made and thus the application area of PCB micro-drilling is broadened.

Development of a Reverse Micro EDM-Drilling for Holing Diamond-Tool

2010 ◽  
Vol 126-128 ◽  
pp. 802-807
Author(s):  
Shun Tong Chen ◽  
Zong Han Jiang ◽  
Yi Ying Wu ◽  
Hong Ye Yang
Keyword(s):  
Diamond Tool ◽  
Dimensional Accuracy ◽  
Sintered Alloy ◽  
Micro Edm ◽  
Hollow Shaft ◽  
Discharge Capacitance ◽  
Micro Holes ◽  
Micro Hole ◽  
Micro Tool ◽  
Edm Drilling

This study presents the development of a drilling technique for an innovative tabletop drilling machine that combines micro-EDM with drilling to fabricate micro-holes in diamond-tool. The mechanisms designs of double V-shaped bearings and double spindles which provide a precision clamping and vertical alignment for diamond-tool and micro-tube are devised to enable to machine a co-centric micro-hole for micro-tool. A diamond-tool, made with copper-based sintered alloy, is drilled by using the developed technique of co-centric micro-hole EDM-drilling into a hollow shaft which can create equilibrium of drilling forces, prevent a drilling squeezing to be occurred and enable to offer a temporary storing space for drilling chips. Relative experiments including the determinations of drilling ratio and discharge capacitance are carried out via this established machine. Experimental results show that excellent geometric and dimensional accuracy of micro-holes on the diamond-tool can be achieved.

A Method of Machining Micro Hole and Micro Cavity in Ceramics

2011 ◽  
Vol 130-134 ◽  
pp. 923-926 ◽  
Author(s):  
Jian Zhong Li ◽  
Tao Wu ◽  
Long Zhang
Keyword(s):  
Tool Path ◽  
Electrical Discharge Machining ◽  
Hole Drilling ◽  
Final Size ◽  
Shrinkage Ratio ◽  
Micro Electrical Discharge Machining ◽  
Micro Holes ◽  
Micro Hole ◽  
Micro Tool ◽  
Micro Cavity

For machining micro hole and micro cavity in ceramics, a manufacturing methods based on green machining have been systematically researched. The micro tool was prepared on-machine by micro electrical discharge machining (EDM). The tool size for micro hole drilling was determined based on extensive experimental results of the sintering shrinkage ratio and the gap caused by the removed ceramics particles between the tool and the workpiece to achieve the desired hole diameter. The tool path design was based on the tool size, the shrinkage ratio and the gap which is different from that in micro hole drilling. Micro holes with diameter of 100μm and micro cavities with upper surface size of 500μm×500μm was machined in ceramics successfully by this method. The final size error was controlled less than 2.25% in micro hole drilling and less than 2% in micro cavity generation.

Investigation of pulsed electrochemical micro-drilling on titanium alloy in the presence of complexing agent in electrolyte

2018 ◽  
Vol 1 (2) ◽  
pp. 142-153 ◽  
Author(s):  
Mukesh Tak ◽  
Vedanth Reddy S ◽  
Abhijeet Mishra ◽  
Rakesh G. Mote
Keyword(s):  
Titanium Alloy ◽  
Titanium Alloys ◽  
Electrochemical Machining ◽  
Chemical Properties ◽  
Machining Process ◽  
Electrochemical Micromachining ◽  
Complexing Agent ◽  
Machined Surface ◽  
Micro Holes ◽  
Micro Drilling

Titanium and its alloys have excellent mechanical and chemical properties; however, these properties make the processing of titanium alloys more challenging compared with other engineering materials. Electrochemical micromachining (ECMM) is a non-conventional machining process, which removes material through anodic dissolution regardless of the material’s hardness. However, during the electrochemical machining of titanium, the formation of a passive oxide layer inhibits further material removal and deteriorates the machined surface quality. In addition, the accuracy of micromachining of titanium alloys is especially affected by the formation of electrolysis precipitates such as TiO2 and stray current dissolution. In this study, the effect of the addition of the complexing agent to different electrolytic solutions on the radial overcut during micro-drilling of titanium alloy grade 5 (Ti6Al4V) has been experimentally studied using the in-house developed ECMM set-up. The influence of parameters such as applied voltage and different electrolytic concentration with and without the complexing agent on overcut during ECMM on Ti6Al4V of micro-holes has been studied. It has been safely concluded that the quality of micro-holes fabricated in the presence of EDTA in the electrolyte while machining is responsible for better dimensional characteristics.

scholarly journals Desktop Micro-EDM System for High-Aspect Ratio Micro-Hole Drilling in Tungsten Cemented Carbide by Cut-Side Micro-Tool

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 675 ◽  
Author(s):  
Yung-Yi Wu ◽  
Tzu-Wei Huang ◽  
Dong-Yea Sheu
Keyword(s):  
Aspect Ratio ◽  
Large Scale ◽  
Cemented Carbide ◽  
Hole Drilling ◽  
Scale Production ◽  
Micro Edm ◽  
Micro Holes ◽  
Micro Hole ◽  
Micro Tool ◽  
Micro Tools

Tungsten cemented carbide (WC-Co) is a widely applied material in micro-hole drilling, such as in suction nozzles, injection nozzles, and wire drawing dies, owing to its high wear resistance and hardness. Since the development of wire-electro-discharge grinding (WEDG) technology, the micro-electrical discharge machining (micro-EDM) has been excellent in the process of fabricating micro-holes in WC-Co material. Even though high-quality micro-holes can be drilled by micro-EDM, it is still limited in large-scale production, due to the electrode tool wear caused during the process. In addition, the high cost of precision micro-EDM is also a limitation for WC-Co micro-hole drilling. This study aimed to develop a low-cost desktop micro-EDM system for fabricating micro-holes in tungsten cemented carbide materials. Taking advantage of commercial micro tools in a desktop micro-EDM system, it is possible to reach half the amount of large-scale production of micro-holes. Meanwhile, it is difficult to drill the deep and high aspect ratio micro-holes using conventional micro-EDM, therefore, a cut-side micro-tool shaped for micro-EDM system drilling was exploited in this study. The results show that micro-holes with a diameter of 0.07 mm and thickness of 1.0 mm could be drilled completely by cut-side micro-tools. The roundness of the holes were approximately 0.001 mm and the aspect ratio was close to 15.

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