• Title/Summary/Keyword: Micro-milling

Search Result 227, Processing Time 0.03 seconds

Analysis of Micro Machining Characteristics using End-milling and Its Applications (초소경 엔드밀링을 이용한 미세 가공특성 분석 및 응용가공)

  • Choi, Hwan-Jin;Park, Eun-Suk;Jeon, Eun-Chae;Je, Tae-Jin;Choi, Doo-Sun
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.29 no.12
    • /
    • pp.1279-1284
    • /
    • 2012
  • Micro structures which are widely used at various fields are commonly fabricated by lithograph, etching and laser methods. Recently, with the emergence of micro tools and ultra-precision machine tools, fabrication of the micro structures obtained using end-milling are studied. However, there are some problems due to the diameter of the micro end-mill getting smaller below $100{\mu}m$. The micro run-out resulted from miniaturization of end-mills have influence seriously on accuracy of micro structures. The error of run-out with a tooling jig showed a decrease of about $9.3{\mu}m$. Furthermore, micro structures with width of $30{\mu}m$ could be applied through experiments of slot machining obtained using 30 and $50{\mu}m$ end-mill. Also, narrow angle structures with $30^{\circ}$ angle could be applied through analysis of machining acute angle structures. Based on basic experiments, micro fluidics channels and spiral patterns for air bearing were machined.

Effect of Powder Mixing Process on the Characteristics of Hybrid Structure Tungsten Powders with Nano-Micro Size (나노-마이크로 크기 하이브리드 구조 텅스텐 분말특성에 미치는 분말혼합 공정의 영향)

  • Kwon, Na-Yeon;Jeong, Young-Keun;Oh, Sung-Tag
    • Journal of Powder Materials
    • /
    • v.24 no.5
    • /
    • pp.384-388
    • /
    • 2017
  • The effect of the mixing method on the characteristics of hybrid-structure W powder with nano and micro sizes is investigated. Fine $WO_3$ powders with sizes of ${\sim}0.6{\mu}m$, prepared by ball milling for 10 h, are mixed with pure W powder with sizes of $12{\mu}m$ by various mixing process. In the case of simple mixing with ball-milled $WO_3$ and micro sized W powders, $WO_3$ particles are locally present in the form of agglomerates in the surface of large W powders, but in the case of ball milling, a relatively uniform distribution of $WO_3$ particles is exhibited. The microstructural observation reveals that the ball milled $WO_3$ powder, heat-treated at $750^{\circ}C$ for 1 h in a hydrogen atmosphere, is fine W particles of ~200 nm or less. The powder mixture prepared by simple mixing and hydrogen reduction exhibits the formation of coarse W particles with agglomeration of the micro sized W powder on the surface. Conversely, in the powder mixture fabricated by ball milling and hydrogen reduction, a uniform distribution of fine W particles forming nano-micro sized hybrid structure is observed.

Effects of Machining Conditions for Improvement of Surface Roughness on Micro End-Milling (마이크로 엔드밀 가공시 가공인자가 표면거칠기 향상에 미치는 영향)

  • Cho, Byoung-Moo;Kim, Sang-Jin;Park, Hee-Sang;Bae, Myung-Il
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.17 no.2
    • /
    • pp.71-76
    • /
    • 2008
  • Micro end-milling is one of effective technology that is able to do ultra-precision machining while increasing the productivity and has wide application field. But selection of machining condition is very difficult because of complicated machining mechanism. Therefore this study was carried out to select working factors to get the optimum surface roughness. Machining condition are depth of cut, feed rate and spindle revolution. The result of this study showed that Surface roughness was affected, in the other of depth of cut, spindle revolution, feed rate. And this study provided an regression equation relating surface roughness to working factors through Regression Analysis and determination coefficient of regression equation had a satisfactory reliability of 79%.

Effect of Dispersion Method on Formation of Electroless Ni-CNT Coatings (분산법이 무전해 Ni-CNT 복합도금막 형성에 미치는 영향)

  • Bae, KyooSik
    • Journal of the Semiconductor & Display Technology
    • /
    • v.13 no.3
    • /
    • pp.51-55
    • /
    • 2014
  • Ni-CNT(Carbon Nanotubes) composite coating is often used for the surface treatment of mechanical/electronic devices to improve the properties of the Ni coating. For the Ni-CNT coating, the dispersion of CNT fibers is a critical process. In this study, ultrasonic treatment instead of the conventional ball milling was attempted as a dispersion method for the electroless Ni-CNT coating. SEM-EDX analysis was performed and contact angle, sheet resistance, and micro-hardness were measured. Results showed that the ultrasonic treatment was comparable to the ball milling, as a dispersion method, but the difference was negligible. However, combined ball milling and ultrasonic treatment(double treatment) showed much improved micro-hardness value, above 350Hv(close to the value obtained by the Ni-CNT electroplating). In addition, electroless Ni-CNT(double-treated) coatings formed on the thin Ni film deposited by the electroless plating(double coating) showed better mechanical properties. Thus, double treatment and double coating are suggested as an improved electroless Ni-CNT coating method.

Characteristics of the Femto-second Pulsed Laser Ablation according to Feed Velocity on the Invar Alloy (펨토초 레이저의 이송속도에 따른 Invar 합금의 어블레이션 특성)

  • Chung, Il-Young;Kang, Kyung-Ho;Kim, Jae-Do;Sohn, Ik-Bu;Noh, Young-Chul;Lee, Jong-Min
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.26 no.3
    • /
    • pp.25-31
    • /
    • 2009
  • Femto-second laser ablation with the various feed velocities of the Invar alloy and the micro surface milling for the processing condition were studied. We used a regenerative amplified Ti:sapphire laser with a 1kHz repetition rate, 184fs pulse duration time and 785nm wavelength. Femto-second laser pulse was irradiated on the Invar alloy with the air blowing at the condition of various laser peak powers and feed velocities. An ablation characteristic according to feed velocity of the Invar alloy was appeared as the non-linear type at different zone of energy fluence. The micro surface milling of the Invar alloy using a mapping method was investigated. The optimal condition of micro surface milling was laser peak power of 22.8mW, feed velocity of 1 mm/s, beam gap of $1{\mu}m$. With the optimal processing condition, the fine rectangular shape without burr and thermal damage was achieved. Using the femto-second laser system, it demonstrates excellent tool for micro surface milling of the Invar alloy without heat effects and poor edge.

Multi-signal characteristics for condition monitoring of micro machined surface (미세가공면의 상태 감시를 위한 다중신호특성에 관한 연구)

  • Jang, Su-Hoon;Park, Jin-Hyo;Kang, Ik-Soo;Kim, Jeong-Suk
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.8 no.1
    • /
    • pp.31-36
    • /
    • 2009
  • Micro-machining technology has been adopted for shape accuracy of micrometer and sub-micrometer scale, surface roughness of tens nanometer in industries. In micro-machining process the quality of machined surface is derived from machining condition and tooling. This paper investigates AE(acoustic emission) and cutting force signals according to machined surface quality related to machining condition. Machined surface quality was analyzed by the AE and cutting force parameter which reflect surface morphology. The characteristics of signal were extracted for process optimization by monitoring both the tool condition and the machined surface texture in micro end milling process.

  • PDF

Micromachining Using Hybrid of Laser Beam and Electrical Discharge Machining (레이저 빔 가공과 방전 가공을 이용한 복합 미세 가공)

  • Kim, San-Ha;Chung, Do-Kwan;Kim, Bo-Hyun;Oh, Kwang-Hwan;Jeong, Sung-Ho;Chu, Chong-Nam
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.26 no.10
    • /
    • pp.108-115
    • /
    • 2009
  • Although nanosecond pulsed laser drilling and milling are rapid and non-wear processes in micromachining, the quality cannot meet the precision standard due to the recast layer and heat affected zone. On the other hand, electrical discharge machining (EDM) is a well-known high precision machining process in micro scale; however, the low material removal rate (MRR) and tool wear remain as drawbacks. In this paper, hybrid process of laser beam machining (LBM) using nanosecond pulsed laser and micro EDM was studied for micro drilling and milling. While the quality of the micro structure fabricated by this hybrid process remains as high as direct EDM, the machining time and tool wear can be reduced. In addition, variable depth of layer was introduced as an effective method improving efficiency of hybrid milling.