• Title/Summary/Keyword: 극미량 윤활

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Numerical Analysis of Thermal Characteristics of a Milling Process of Titanium Alloy Using Nanofluid Minimum-Quantity Lubrication (티타늄 합금의 나노유체 극미량 윤활 밀링 공정 열특성에 관한 수치 해석 연구)

  • Kim, Young Chang;Kim, Jin Woo;Kim, Jung Sub;Lee, Sang Won
    • Journal of the Korean Society for Precision Engineering
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    • v.34 no.4
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    • pp.253-258
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    • 2017
  • This paper presents a numerical study on the thermal characteristics of a milling process of titanium alloy with nanofluid minimum-quantity lubrication (MQL). The computational fluid dynamics (CFD) approach is introduced for establishing the numerical model for the nanofluid MQL milling process, and estimated temperatures for pure MQL and for nanofluid MQL using both hexagonal boron nitride (hBN) and nanodiamond particles are compared with the temperatures measured by thermocouples in the titanium alloy workpiece. The estimated workpiece temperatures are similar to experimental ones, and the model is validated.

Experimental Characterization of Turning Process of Titanium Alloy Using Cryogenic Cooling and Nanofluid Minimum Quantity Lubrication (극저온 냉각 및 나노유체 극미량 윤활을 적용한 티타늄 합금의 선반 절삭가공 특성에 관한 연구)

  • Kim, Jin Woo;Kim, Jung Sub;Lee, Sang Won
    • Journal of the Korean Society for Precision Engineering
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    • v.34 no.3
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    • pp.185-189
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    • 2017
  • Recently, titanium alloys have been widely used in aerospace, biomedical engineering, and military industries due to their high strength to weight ratio and corrosion resistance. However, it is well known that titanium alloys are difficult-to-cut materials because of a poor machinability characteristic caused by low thermal conductivity, chemical reactivity with all tool materials at high temperature, and high hardness. To improve the machinability of titanium alloys, cryogenic cooling with LN2 (Liquid Nitrogen) and nanofluid MQL (Minimum Quantity Lubrication) technologies have been studied while turning a Ti-6Al-4V alloy. For the analysis of turning process characteristics, the cutting force, the coefficient of friction, and the surface roughness are measured and analyzed according to varying lubrication and cooling conditions. The experimental results show that combined cryogenic cooling and nanofluid MQL significantly reduces the cutting forces, coefficients of friction and surface roughness when compared to wet condition during the turning process of Ti-6Al-4V.

Ultra Precision Machining Characteristics of PMMA in HMD optical system (HMD 광학계용 PMMA의 초정밀 가공 특성)

  • Yang J.S.;Kim G.H.;Yang S.C.;Lee I.J.;Kim M.S.;Lee D.J.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1566-1570
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    • 2005
  • The aspherical lenses are used as optical lens of HMD optical system. The optimum cutting condition of PMMA lens sample with ultra precision SPDT, the diamond tool nose radius, the cutting speed, the feed rate, the depth of cut, and cutting fluid type are found. The demanded surface roughness 10 nm Ra, aspherical form error $1.0\;\mu{m}$ P-V for aspherical lens of optical data storage device are satisfied.

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The Characteristics of SIL Lens Machining Using Diamond Turning Machine (초정밀가공기를 이용한 SIL 렌즈의 절삭특성)

  • Won, Jong-Ho;Park, Won-Kyoo;Kim, Ju-Hwan;Kim, Geon-Hee
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.2 no.1
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    • pp.63-68
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    • 2003
  • The aspherical lenses are used as objective lens of optical pickup. To examine the design factor the sample product is made before manufacturing of injection mould of lens. The optimum cutting condition of PMMA lens sample with ultra precision SPDT, the roam spindle speed, the depth of cut, the feedrate are found. The demanded surface roughness 100m Ra, aspherical form error $0.5{\mu}m$ P-V for aspherical lens of optical data storage device are satisfied.

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A study of Pickup Lens manufacturing in diamond turing machine (초정밀가공기를 이용한 광 저장용 렌즈의 절삭특성)

  • 김건희;홍권희;김효식;박지영;박원규
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.891-894
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    • 1997
  • The asphericals lenses are used as objective lens of optical pickup. To examine the design factor the sample product is made before manufacturing of injection mould of lens. The optimum cutting condition of PMMA lens sample with ultra precision SPDT, he main spindle sped, the depth of cut, the feedrate are found. The demanded surface roughness 10nm Ra, aspherical form error 0.5${\mu}{\textrm}{m}$ P-V for aspherical lens of optical data storage device are satisfied.

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A Study on High Speed Machining Distortion Characteristics of Aluminum Lithium Alloys Wing Rib (Al-Li 합금 윙립의 고속가공 변형특성에 관한 연구)

  • Lee, In-Su;Kim, Hae-Ji
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.6
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    • pp.111-118
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    • 2014
  • Aluminum lithium alloys are new materials developed for lightweight aircraft parts. However, as compared with conventional aluminum alloys in high-speed machining, problems such as tool wear, machining distortion, and cutting ability arise. This study presents the machining distortion characteristics of an Al-Li alloy wing tip in relation to the cutting heat in high-speed machining. A machining experiment was conducted with high-speed machining equipment for an evaluation of the machining distortion characteristics, with each machining stage temperature change of the workpiece machining surface, and the inside and outside temperature changes of the equipment measured. By measuring the amount of distortion of the workpiece before and after machining, the cutting heat was analyzed with regard to its effect on machining distortion in the product.

Semidry-cutting Characteristics according to Workpiece Materials (공작물 재질에 따른 세미드라이 절삭가공 특성)

  • Lee, Jong-Hang;Park, Cheol-Woo;Lee, Seok-Woo;Choi, Hon-Zong
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.968-973
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    • 2003
  • As environmental restrictions have continuously become more strict, it has emphasized development of environment-friendly technologies. In cutting technology, it has been well recognized that cutting fluids might have undesirable effects on worker's health and working environment and, hence, recently there have been numerous attempts to minimize harmful effects of cutting fluids on environments. To minimize the use of cutting fluids in machining, conventional cutting fluids have been replaced with the technologies of pressurized cold air and minimum quantity lubrication(MQL). Compared with milling, turning is a continuous cutting process, where tools are continuously heated up and lack of lubricity could lead to tool wear and deteriorated surface roughness. In this study, it has been investigated how tool wear and surface roughness could be affected by cutting conditions, supply and cooling methods. The experimental results show that MQL technology is able to minimize harmful effects of conventional cutting fluids.

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A Study on the Optimum Shape of MQL Carbide End-mill for Machining of Aluminum Lithium Alloy (Al-Li 합금 가공용 MQL 초경공구의 최적 형상에 관한 연구)

  • Lee, In-Su;Kim, Hae-Ji
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.12 no.6
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    • pp.159-166
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    • 2013
  • In order to develop the optimum shape of an MQL carbide end-mill suitable for high speed machining of wing ribs which are a detailed part of larger wing structures, using a new material Al-Li alloy, a new MQL carbide end-mill is created that has various quantities of holes, hole sizes, and hole locations. A theoretical machining graph is generated using the hammer test and FRF simulation, and a machining test is performed in order to verify the machining stability in the high speed machining area. The optimum configuration of the MQL carbide end-mill is also presented through comparing the chattering, machining noise and cutting conditions, including the maximum cutting depth, rpm, and feed rate per teeth, for each cutter.