• 제목/요약/키워드: Material Removal rate

검색결과 593건 처리시간 0.033초

Characteristics of Si3N4 Laser Assisted Machining according to the Laser Power and Feed Rate

  • Kim, Jong-Do;Lee, Su-Jin;Suh, Jeong
    • Journal of Advanced Marine Engineering and Technology
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    • 제34권7호
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    • pp.963-970
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    • 2010
  • This study makes an estimate of the laser-assisted machining (LAM) of an economically viable process for manufacturing precision silicon nitride ceramic parts using a high-power diode laser (HPDL). The surface is locally heated by an intense laser source prior to material removal, and the resulting softening and damage of the workpiece surface simplify the machining of the ceramics. The most important advantage of LAM is its ability to produce much better workpiece surface quality compared to conventional machining. Also important are its larger material removal rates and longer tool life. The cutting force and surface temperature were measured on-line using a pyrometer and a dynamometer, respectively. Tool wear, chips and the surface of the workpiece were measured using optical microscopy, and the surface and fractured cross-section of $Si_3N_4$ were measured by SEM. During the LAM process, the cutting force and tool wear were reduced and oxidation of the machined surface was increased according to the increase in the laser power. Moreover, the more the feed rate increased, the more the cutting force and tool wear increased.

자성유체를 이용한 연마 (Magnetorheological Finishing)

  • 신영재;이응숙;황경현;김경웅
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2000년도 추계학술대회 논문집
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    • pp.775-778
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    • 2000
  • Magnetorheological Finishing(MRF) is a newly developed and recently commercialized for finishing optical components. The magnetorheological fluid consists of a water based suspension of carbonyl iron, nonmagnetic polishing abrasives, and small amounts of stabilizer. Theoretical analysis of MRF, based on Bingham lubrication theory, is illustrated and a correlation between surface shear stress on the workpiece and material removal is obtained.

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MR 유체 제트 연마를 이용한 광학유리의 가공성능 (Machining Performance of Optical Glass with Magnetorheological Fluid Jet Polishing)

  • 김원우;김욱배
    • 한국정밀공학회지
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    • 제28권8호
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    • pp.929-935
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    • 2011
  • As a deterministic finishing process for the optical parts having complex surface, machining performance of the magnetorheological(MR) fluid jet polishing of optical glass are studied and compared with a general water jet polishing. First, design of the jet polishing system which has the special electromagnet-nozzle unit for stabilizing the slurry jet based on MR fluid and the change of jet shape as magnetic field is applied are explained. Second, for the BK7 glass, machining spot and its cross section profile are analyzed and the unique effect of MR fluid jet polishing is shown. Third, both material removal depth and surface roughness are explored in order to investigate the polishing performance of MR fluid jet. With the same ceria abrasives and amount in the polishing slurries, MR fluid jet shows superior machining performance compared to water jet and the difference of material removal mechanism and its resulting performance are described.

입자연마가공에서의 압력 속도 및 유체점도의 영향에 대한 고찰 (A Study of the Effects of Pressure Velocity and Fluid Viscosity in Abrasive Machining Process)

  • 양우열;양지철;성인하
    • Tribology and Lubricants
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    • 제27권1호
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    • pp.7-12
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    • 2011
  • Interest in advanced machining process such as AJM(abrasive jet machining) and CMP(chemical-mechanical polishing) using micro/nano-sized abrasives has been on the increasing demand due to wide use of super alloys, composites, semiconductor and ceramics, which are difficult to or cannot be processed by traditional machining methods. In this paper, the effects of pressure, wafer moving velocity and fluid viscosity were investigated by 2-dimensional finite element analysis method considering slurry fluid flow. From the investigation, it could be found that the simulation results quite corresponded well to the Preston's equation that describes pressure/velocity dependency on material removal. The result also revealed that the stress and corresponding material removal induced by the collision of particle may decrease under relatively high wafer moving speed due to the slurry flow resistance. In addition, the increase in slurry fluid viscosity causes the reduction of material removal rate. It should be noted that the viscosity effect can vary with the shape of abrasive particle.

Evaluation of Mixing Effects on Solid-state Anaerobic Digestion Performance of Dairy Manure and Sawdust Bedding Mixtures

  • Jo, Hyeonsoo;Lee, Seunghun;Lee, Jaehee;Kim, Eunjong;Ahn, Heekwon
    • 한국토양비료학회지
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    • 제49권3호
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    • pp.227-234
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    • 2016
  • The influence of mixing on biogas production and organic material removal performance of solid state anaerobic digestion of dairy manure and sawdust bedding mixtures was evaluated using 22 L volume lab-scale digesters. After 45 days of anaerobic digestion at $37^{\circ}C$, cumulative methane yield of unmixed test unit ($73.1N{\cdot}mL/g-VS$) was almost 1.3 times of that of mixed one ($56.3N{\cdot}mL/g-VS$). The biodegradable volatile solids removal rate of unmixed test unit was 67%, which was almost 28% greater than mixed one. Our results reveal that unmixed condition is better than mixed one in terms of biogas production and organic material reduction.

파우더 블라스팅을 이용한 유리 가공시 실험계획법에 의한 가공면 분석 (Predictive modeling of surface roughness and material removal In powder blasting of glass by design of experiments)

  • 김권흡;김정근;한진용;성은제;박동삼;유우식
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 추계학술대회 논문집
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    • pp.681-684
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    • 2005
  • The old technique of sandblasting which has been used for paint or scale removing, deburring, and glass decorating has recently been developed into a powder blasting technique for brittle materials, capable of producing micro structures larger than 100um. A large number of Investigations on the abrasive jet machining with output parameters as material removal rate, penetrate and surface finish have been carried out and reported by various authors. In this paper, we investigated the effect of surface characteristics and surface shape of the abrasive jet machined glass surface under different blasting parameter. and finally we established a model for abrasive flow machining process, and compared with experimental results.

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자외선 광을 활용하는 화학기계적 연마에 관한 연구 동향 (Research Trends on Chemical Mechanical Polishing Using Ultraviolet Light)

  • 이현섭
    • Tribology and Lubricants
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    • 제38권6호
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    • pp.247-254
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    • 2022
  • Chemical mechanical polishing (CMP) is a hybrid surface-polishing process that utilizes both mechanical and chemical energy. However, the recently emerging semiconductor substrate and thin film materials are challenging to process using the existing CMP. Therefore, previous researchers have conducted studies to increase the material removal rate (MRR) of CMP. Most materials studied to improve MRR have high hardness and chemical stability. Methods for enhancing the material removal efficiency of CMP include additional provision of electric, thermal, light, mechanical, and chemical energies. This study aims to introduce research trends on CMP using ultraviolet (UV) light to these methods to improve the material removal efficiency of CMP. This method, photocatalysis-assisted chemical mechanical polishing (PCMP), utilizes photocatalytic oxidation using UV light. In this study, the target materials of the PCMP application include SiC, GaN, GaAs, and Ru. This study explains the photocatalytic reaction, which is the basic principle of PCMP, and reviews studies on PCMP according to materials. Additionally, the researchers classified the PCMP system used in existing studies and presented the course for further investigation of PCMP. This study aims to aid in understanding PCMP and set the direction of future research. Lastly, since there have not been many studies on the tribology characteristics in PCMP, research on this is expected to be required.

강자성체와 나노사이즈의 프러시안 블루가 합성된 새로운 형태의 복합체 제조 및 최적의 적용 조건 도출 (Manufacture of Novel Composites Synthesized with Ferromagnetic and Nano-Sized Prussian Blue and D eriving Optimum Conditions)

  • 김종규
    • 한국재료학회지
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    • 제33권4호
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    • pp.151-158
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    • 2023
  • In this study, a new type of composite material combined with carbonyl iron, a relatively strong ferromagnetic material, was prepared to overcome the current application limitations of Prussian blue, which is effective in removing radioactive cesium. The surface of the prepared composite was analyzed using SEM and XRD, and it was confirmed that nano-sized Prussian Blue was synthesized on the particle surface. In order to evaluate the cesium removal ability, 0.2 g of the composite prepared for raw cesium aquatic solution at a concentration of 5 ㎍ was added and reacted, resulting in a cesium removal rate of 99.5 %. The complex follows Langmuir's adsorption model and has a maximum adsorption amount (qe) of 79.3 mg/g. The Central Composite Design (CCD) of the Response Surface Method (RSM) was used to derive the optimal application conditions of the prepared composite. The optimal application conditions achieved using Response optimization appeared at a stirring speed of pH 7, 17.6 RPM. The composite manufactured through this research is a material that overcomes the Prussian Blue limit in powder form and is considered to be excellent economically and environmentally when applied to a cesium removal site.

정밀여과·나노여과·역삼투 막에 의한 세슘과 요오드의 제거 (Removal of cesium(137Cs) and iodide(127I) by microfiltration·nanofiltration·reverese osmosis membranes)

  • 채선하;김충환
    • 상하수도학회지
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    • 제28권5호
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    • pp.549-554
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    • 2014
  • This study was evaluated the applicability of the membrane filtration process (Micro Filtration (MF), nanofiltration membranes (NF), reverse osmosis (RO)) on the major radioactive substances, iodine ($I^-$) and cesium ($Cs^+$) using membranes produced in Korea and domestic raw water. Iodine ($I^-$) or cesium ($Cs^+$) in the microfiltration membrane (MF) process could not be expected removal efficiency by eliminating marginally at the combined state with colloidal and turbidity material. At the domestic raw water (lake water, turbidity 1.2 NTU, DOC 1.3 mg/L) conditions, nanofiltration membrane (NF) and reverse osmosis (RO) showed a high removal rate of about 88 ~ 99% for iodine ($I^-$) and cesium ($Cs^+$) and likely to be an alternative process for the removal of radioactive material.