scholarly journals Precision EDM of Micron-Scale Diameter Hole Array Using in-Process Wire Electro-Discharge Grinding High-Aspect-Ratio Microelectrodes

Micromachines ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 17
Author(s):  
Zhixiang Zou ◽  
Zhongning Guo ◽  
Qinming Huang ◽  
Taiman Yue ◽  
Jiangwen Liu ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Turbine Blades ◽  
Hole Array ◽  
Machining Accuracy ◽  
Micro Edm ◽  
Wire Vibration ◽  
Micro Hole ◽  
The Wire

Micro-electrical discharge machining (micro-EDM) is a good candidate for processing micro-hole arrays, which are critical features of micro-electro-mechanical systems (MEMS), diesel injector nozzles, inkjet printheads and turbine blades, etc. In this study, the wire vibration of the wire electro-discharge grinding (WEDG) system has been analyzed theoretically, and, accordingly, an improved WEDG method was developed to fabricate micron-scale diameter and high-aspect-ratio microelectrodes for the in-process micro-EDM of hole array with hole diameter smaller than 20 μm. The improved method has a new feature of a positioning device to address the wire vibration problem, and thus to enhance microelectrodes fabrication precision. Using this method, 14 μm diameter microelectrodes with less than 0.4 μm deviation and an aspect ratio of 142, which is the largest aspect ratio ever reported in the literature, were successfully fabricated. These microelectrodes were then used to in-process micro-EDM of hole array in stainless steel. The effects of applied voltage, current and pulse frequency on hole dimensional accuracy and microelectrode wear were investigated. The optimal processing parameters were selected using response–surface experiments. To improve machining accuracy, an in-process touch-measurement compensation strategy was applied to reduce the cumulative compensation error of the micro-EDM process. Using such a system, micro-hole array (2 × 80) with average entrance diameter 18.91 μm and average exit diameter 17.65 μm were produced in 50 μm thickness stainless steel sheets, and standard deviations of hole entrance and exit sides of 0.44 and 0.38 μm, respectively, were achieved.

High aspect ratio micro-hole drilling aided with ultrasonic vibration and planetary movement of electrode by micro-EDM

CIRP Annals ◽  
2009 ◽  
Vol 58 (1) ◽  
pp. 213-216 ◽  
Author(s):  
Z.Y. Yu ◽  
Y. Zhang ◽  
J. Li ◽  
J. Luan ◽  
F. Zhao ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Ultrasonic Vibration ◽  
High Aspect Ratio ◽  
Hole Drilling ◽  
Micro Edm ◽  
Micro Hole

Machining of High Aspect Ratio Micro-Holes on Titanium Alloy Using Silver Nano Powder Mixed Micro EDM Drilling

2019 ◽  
Author(s):  
Chong Liu ◽  
Asif Rashid ◽  
Muhammad P. Jahan ◽  
Jianfeng Ma
Keyword(s):  
Titanium Alloy ◽  
Aspect Ratio ◽  
Surface Finish ◽  
High Aspect Ratio ◽  
Electrical Discharge Machining ◽  
Turbine Blades ◽  
Weight Ratio ◽  
Recast Layer ◽  
Micro Edm ◽  
Micro Holes

Abstract Titanium alloy Ti-6Al-4V is used extensively in aerospace engines because of its high strength-to-weight ratio and corrosion resistance. Machining of cooling holes in turbine blades for aerospace engines is one of the major challenges faced in aerospace industries. Ti-6Al-4V is known as a difficult to be machined material by conventional machining processes, and machining of micro-through-holes with diameter less than 100 microns is even more challenging. Therefore, the objective of this study is to investigate the feasibility of machining high aspect ratio micro-through holes in Ti-6Al-4V using micro electrical discharge machining (micro-EDM) with the silver (Ag) nanopowder mixed dielectric. The machining time, overcut, recast layer, crater size, aspect ratio and surface finish of the micro-holes were evaluated. In order to minimize the positional inaccuracy and spindle runout, the microelectrodes were fabricated in-situ using block micro-EDM process. In this study, as received electrode of 300 microns diameter tungsten wire was reduced to about 50 microns diameter rod by micro block EDM using a tungsten carbide block. The effect of powder concentration, gap voltage, capacitance and electrode rotational speed was studied. It is found that high quality micro-holes of about 50 microns diameter can be achieved successfully and repeatedly using powder mixed micro-EDM (PM-μEDM). The micro-holes generated by PM-μEDM provides comparatively smoother surface finish and minimal recast layer around the rim of the micro-holes. In addition, PM-μEDM process improves machining stability, thus allowing to minimize the hole size and quality, thus enhancing the aspect ratio of micro-holes.

scholarly journals Fabrication of Micro-Parts with High-Aspect Ratio Micro-Hole Array by Micro-Powder Injection Molding

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1864 ◽  
Author(s):  
Changrui Wang ◽  
Zhen Lu ◽  
Kaifeng Zhang
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Linear Shrinkage ◽  
Powder Injection ◽  
Hole Array ◽  
Particle Sizes ◽  
Crystalline Particle ◽  
Average Deviation ◽  
Micro Holes ◽  
Micro Hole

The present study investigated high-aspect ratio micro-hole array parts which were made by ZrO2 micro-powder with different particle sizes and micro-powder injection molding technology. It analysed the influence of particle sizes on feedstock, debinding and sintering of ceramic nozzles with multi-micro-holes. The forming quality of ceramic nozzles with multi-micro-holes was discussed in this paper. The results show that the two mixed ZrO2 feedstocks have fine uniformity. The average deviation of the feedstock made with 200 nm powder was −2%, and the average deviation of the feedstock made with 100 nm powder was −7.1%. The sample showed certain sintering characteristics which provided better strength (11.10 MPa) to parts after debinding. The linear shrinkage and the density of the two powder samples at different sintering temperatures increased as the sintering temperature increased. If the temperature continued to increase, the linear shrinkage and the density decreased. The highest hardness and flexural strength values of the ZrO2 sample with 200 nm powder used were: 1265.5 HV and 453.4 MPa, and the crystalline particle size was 0.36 μm. The highest hardness and flexural strength values of the ZrO2 sample with 100 nm powder used were: 1425.8 HV and 503.6 MPa, and the crystalline particle size was 0.18 μm. The ceramic nozzles with multi-micro holes shrunk to nearly the same axial, radial and circumferential directions during sintering. After sintering, the roundness of ceramic micro-hole met the user requirements, and the circular hole had a high parallelism in the axial direction. The micropore diameter was 450 ± 5 μm, and it was possible to control the dimensional accuracy within 1.5% after sintering. The study presented a superior application prospect for high-aspect ratio micro hole array parts in aerospace, electronics and biomedicine.

Micro extrusion of high aspect ratio bi-lumen tubes using 17-4PH stainless steel feedstock

2020 ◽  
Vol 58 ◽  
pp. 443-457
Author(s):  
Sandeep Kuriakose ◽  
Paolo Parenti ◽  
Massimiliano Annoni
Keyword(s):  
Stainless Steel ◽  
Aspect Ratio ◽  
High Aspect Ratio

High aspect ratio meso-scale parts enabled by wire micro-EDM

2002 ◽  
Vol 8 (6) ◽  
pp. 395-401 ◽  
Author(s):  
G. L. Benavides ◽  
L. F. Bieg ◽  
M. P. Saavedra ◽  
E. A. Bryce
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Micro Edm ◽  
Meso Scale
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