Experimental Study on Electrochemical Drilling of Micro Holes with High Aspect Ratio

2014 ◽  
Vol 941-944 ◽  
pp. 1952-1955 ◽  
Author(s):  
Yong Liu ◽  
Shao Fu Huang

It is a difficult problem to fabricate deep and micro holes on the difficult-to-cut metals in the field of aviation manufacturing. The experimental research of electrochemical drilling technology with high-speed micro electrode for fabricating deep micro holes is carried out. The influences of rotary speed on machining precision and stability are studied. The holes, which the diameter is about 400μm, the aspect ratio is more than 10, and have steep wall and sharp edges were fabricated successfully on the nickelbase superalloys on self-developed high-precision micro-electrochemical machining system. It is proved that the high-speed electrochemical drilling process for fabricating deep and micro holes has a huge potential and broad application prospects.

Author(s):  
Ronnie Mathew ◽  
Sagil James ◽  
M. M. Sundaram

Accurate and precise micro tools are essential for the micromachining of highly complex features in a wide variety of engineering materials including metals and ceramics. Simple shapes like cylindrical rods with micrometer level dimensions are increasingly being used as micro tools in processes such as micro ultrasonic machining. High aspect ratio tools are necessary to produce deep micro holes and other high aspect ratio structures. Micro tools produced by the well known wire electro-discharge grinding suffer from deformation due to the thermal stresses. Therefore, alternate micro tool manufacturing techniques are being explored actively. In this paper, the manufacturing of micro tools by micro electrochemical machining (ECM) is discussed. The micro tools are made under different experimental conditions using an in-house built micro electrochemical machining system and analyzed for tool tip radii and cone angles. Further, the feasibility of extremely high aspect ratio micro tools is studied. Using micro ECM, micro tools having mean diameters of 10 microns with tips as small as 50 nm and aspect ratios of the order of 300 are achieved.


Micromachines ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 28 ◽  
Author(s):  
Yong Liu ◽  
Minghong Li ◽  
Jingran Niu ◽  
Shizhou Lu ◽  
Yong Jiang

Fabrication of the injection nozzle micro-hole on the aero engine is a difficult problem in today’s manufacturing industry. In addition to the size requirements, the nozzle micro-hole also requires no burr, no taper and no heat-affected zone. To solve the above problem, an ultra-short voltage pulse and a high-speed rotating helical electrode were used in electrochemical drilling (ECD) process. Firstly, a theoretical model of ECD with ultra-short voltage pulse was established to investigate the effects of many predominant parameters on machining accuracy, and the effect of rotating helical electrode on the gap flow field was analyzed. Secondly, sets of experiments were carried out to investigate the effects of many key parameters on machining accuracy and efficiency. Finally, the optimized parameters were applied to machine micro holes on 500 μm thickness of GH4169 plate, and micro-holes with the diameter of 186 μm with no taper were machined at the feed rate of 1.2 μm/s. It is proved that the proposed ECD process for fabricating micro-holes with no taper has a huge potential and broad application prospects.


2009 ◽  
Vol 69-70 ◽  
pp. 229-233
Author(s):  
Ming Huan Wang ◽  
Qiao Fang Zhang ◽  
C.Y. Yao ◽  
Wei Peng

The machining of materials on microscopic scales is considered to be great importance to a wide variety of fields. Electrochemical Micro-machining (EMM) appears to be promising to machine the micro-structures in future due to the material is dissolved at the unit of ion. This paper is focused on developing a micro electrochemical machining system in which the micro-structures such as micro-cylinder, multiple micro-electrodes, micro-holes and micro-slot were processed. The micro-electrodes were prepared in a precisely controlling the electrochemical etching process. Mathematical model controlling the diameters of electrodes was built up. Furthermore, the obtained micro-electrodes were selected as the cathode tool for micro holes drilling and micro-slot milling using pulse power in Micro-ECM.


2011 ◽  
Vol 295-297 ◽  
pp. 1794-1799 ◽  
Author(s):  
Shao Fu Huang ◽  
Di Zhu ◽  
Yong Bin Zeng ◽  
Wei Wang ◽  
Yong Liu

Electrochemical discharge machining (ECDM), based on electrochemical machining (ECM) and electrodischarge machining (EDM), is an unconventional micro-machining technology. In this paper, with the use of water, the process of micro hole on ANSI 304 stainless steel machined by micro-ECDM with high speed rotating cathode is studied. The effects of machining conditions such as the cathode rotating speed and cathode diameter on the surface quality and accuracy of the shape are investigated. The results indicate that a relatively higher electrode rotating speed can improve the machining accuracy of the micro-holes and reduce the electrodes wear.


2010 ◽  
Vol 447-448 ◽  
pp. 836-840 ◽  
Author(s):  
Eiichi Aoyama ◽  
Toshiki Hirogaki ◽  
Keiji Ogawa ◽  
Satoshi Nojiri ◽  
Yutaka Takeda

A drilling technique using micro-drills of 0.2 mm or less in diameter and a super-high-speed spindle of 160000 rpm or more has been developed for drilling ultra-micro holes in printed wiring boards (PWBs). The drilling process requires higher reliability and quality to maintain the reliability of the electrical connection between circuit layers. On the other hand, higher processing efficiency is also required in PWBs manufacturing. To maintain high productivity, drilling is normally performed using a non-step method, but heat damage called B-RING occurs around the drilled holes with this method. To solve these problems without the loss of processing efficiency, we applied the rapid-feed step-drilling cycle method. We investigated the B-RING for drilling quality and evaluated the drilling time for processing efficiency under various drilling conditions. We found that using a rapid-feed step-drilling cycle with an appropriate number of steps and feed rates ensures a higher level of hole quality and processing efficiency compared with the conventional non-step drilling.


2021 ◽  
Author(s):  
Jesus M. Orona-Hinojos

Electrical discharge machining is a machining method generally used for machining hard metals, those that would be high cost or have poor performance to machine with other techniques using, e.g., lathes, drills, or conventional machining. Therefore, also known as thermal processes like EDM, Plasma or Laser cutting can be used in drilling operations with poor metallurgical quality on cutting edge and will be necessary complement with other processes such as electrochemical machining (ECM). Both ECM and EDM processes use electrical current under direct-current (DC) voltage to electrically power the material removal rate (MRR) from the workpiece. However in ECM, an electrically conductive liquid or electrolyte is circulated between the electrode(s) and the workpiece for permitting electrochemical dissolution of the workpiece material. While the EDM process, a nonconductive liquid or dielectric is circulated between the cathode and workpiece to permit electrical discharges in the gap there between for removing the workpiece material. Both are principle too different, EC using an electrical conductive and ED using a dielectric medium. But exist a way that can to do a combination of Pulsed EC + ED Simultaneous and allowing the coexist both process, in a semidielectric medium, where both condition exist in the same time, therefore in this hybrid is possible create a tooling device dual cathode for drilling process with promissory advantages fast hole for this innovative hybrid ECDM Simultaneous, this hybrid it’s knew as blue arc drilling technology.


2018 ◽  
Vol 777 ◽  
pp. 327-332
Author(s):  
Ornsurang Netprasert ◽  
Noppakao Chimyo ◽  
Suphaphich Phimphun ◽  
Jantakarn Sukjan ◽  
Viboon Tangwarodomnukun ◽  
...  

Electrochemical machining process is an advanced material removal technique offering high precision and introducing no heat damage to the work material. The shape and size of machined area are highly dependent on some process parameters such as voltage, electrolyte and inter-electrode gap. To further enable a more insight into the process performance, this paper investigates the influences of applied voltage, electrolyte concentration and inter-electrode gap on the shape and sizes of hole produced by the electrochemical drilling process. Titanium alloy (Ti-6Al-4V) was used as a work sample in this study as it has been extensively used in many advanced applications. The experimental result indicated that the use of high voltage and high electrolyte concentration can enlarge and deepen hole in the workpiece, while the inter-electrode gap provided less effect to the hole features. The maximum hole depth can reach 300 μm within 60 seconds when the applied voltage of 30 V, the inter-electrode gap of 10 μm and the electrolyte concentration of 10%wt were used. However, with this setup, the obtained cut profile became a non-uniform V-shaped hole. The use of lower voltage was instead recommended to yield a better cut quality with U-shaped profile.


Author(s):  
Harsha Goel ◽  
Usharani Rath ◽  
Pulak M Pandey

Ultrasonic-assisted jet electrochemical micro drilling is an advanced variant of electrochemical machining to drill micro holes quickly and efficiently. The present article deals with the modelling and simulation of the integration of ultrasonic vibration with the conventional jet electrochemical micro drilling process. Multi-physics-based modelling and simulation approach has been used in the present work. The flow pattern of electrolyte jet was analysed for both jet electrochemical micro drilling and ultrasonic-assisted jet electrochemical micro drilling processes. The simulation results were validated with the previous experimental findings of ultrasonic-assisted jet electrochemical micro drilling process. It was found that the material removal rate (MRR) improved significantly as the ultrasonic wave got superimposed onto the electrolyte jet. In addition to that, voltage and concentration of the electrolyte also played vital roles in improving the MRR.


2018 ◽  
Vol 226 ◽  
pp. 03017
Author(s):  
Vladimir V. Glebov ◽  
Irina N. Danilenko ◽  
Ruslan I. Ratushinsky

In this research shaped tube electrolytic machining of drilling and milling of magnetic alloys parts and difficult-to-cut metals, steels and alloys is presented. New research made in the field of space, aviation, automobile, medical, computer and electronics, and others has created the need for small and fine holes with high aspect ratio in these materials. The primary investigations of ECM with the tubular tool electrode are presented. Compared with mechanical machining, shaped tube electrolytic machining (STEM) exhibits an advantage in producing micro-holes with a high aspect ratio and in producing the curved holes. In order to realize the process of electrochemical machining, experimental assembly with the shaped tube tool electrode has been designed and manufactured. Completed researches indicate that this tool electrode has a high potential to machine difficult-to-cut and brittle metals economically and efficiently.


Circuit World ◽  
2014 ◽  
Vol 40 (2) ◽  
pp. 61-70 ◽  
Author(s):  
Linfang Wang ◽  
Lijuan Zheng ◽  
Cheng yong Wang ◽  
Shan Li ◽  
Yuexian Song ◽  
...  

Purpose – Compared with the traditional printed circuit board (PCB) drilling process, the technology of drilling IC substrate is facing more problems, such as much smaller hole diameter, more intensive hole space, thinner sheet and more complicated materials are drilled in process. Moreover, the base material of IC substrate is different from traditional PCB, more kinds of fillers added in IC substrate which make the drill worn seriously during drilling process. Micro-drills wear and micro holes quality are the most important questions when drilling IC substrate so far. Wear morphology of micro-drill, holes wall roughness and hole location accuracy are researched in this paper. The influence factors of micro-drills wear and micro holes quality are also studied in this drilling process. The paper aims to discuss these issues. Design/methodology/approach – Two drills with same structure and different diameter are used to drill different stacks of IC substrate and drill different holes in this paper. There are four experiments made and the drilling parameters including spindle speed (n), feed rate (vf) and retraction speed (vr) are recommended by drill manufacturing company. Wear morphologies of drill are observed, holes wall roughness (Rmax) and holes location accuracy (Cpk) are measured in this paper. Analyzing the main factors influence on drill wear, holes wall roughness and holes location accuracy through these experiments. Findings – The micro-drills of IC substrate wear more severely compared with other material of PCB through the experimental results in this paper. Drill diameter has influence on micro-drill wear when drilling IC substrate, the smaller of drill is, the more severely of micro-drill wears. Drill diameter affect the holes wall roughness too, the holes wall roughness of larger holes is better than smaller one in a certain range. The drilled holes number also has influence on micro-drills wear, holes wall roughness and holes location accuracy. The more drilled holes, the seriously of micro-drills wear, and the worn drill would destroy the hole quality. Therefore, the more drilled holes lead the bad holes wall roughness and holes location accuracy in this paper. In addition, stacks of IC substrate affect much on the holes location accuracy, the more stacks, the worse holes location accuracy. Originality/value – Chinese Mainland is obviously lagging behind in technology and manufacturer of IC substrate which is incompatible with the nation circumstances. There is few research of drilling IC substrate in China and research data are lacking so far. It is most necessary to improve the technology level of drilling IC substrate in China. In order to reduce the wear of micro-drills and improve the quality of micro-holes, many experimental tests about drilling IC substrate are researched in this paper.


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