• Title/Summary/Keyword: Compressed Air

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Evaluation of Machinability of Micro groove by Cutting Environments in High Speed Machining using Ball End Mill (소구경 미세홈 고속가공시 가공환경변화에 따른 가공성 평가)

  • 정연행;이태문;강명창;이득우;김정석
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.04a
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    • pp.32-37
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    • 2002
  • High speed machining is one of most effective technologies to improve productivity. It can give great advantage for manufacture of die and Moulds. However, when the high speed machining of materials, especially in machining of micro groove, a severely thermal demage was generated on workpiece and tool. Generally, the cutting fluid is used to improve penetration, lubrication, and cooling effect. In order to rise the performance of lubrication, it contains extreme pressure agents (Cl, S, P). But the environment of work room go bad by those additive Therefore, the compressed chilly air with Oil mist system was developed to replace the conventional cutting fluid system. This paper carried out the tests to evaluate the machinability by the cutting environment in high speed micro groove machining of NAK80 (HRC40). Compressed chilly air with oil mist was ejected on the contact area between cutting edge and workpiece. The effectiveness of this developed compressed chilly air with oil mist system was evaluated in terms of tool life. The results showed that the tool life of carbide tool coated TiAIN with compressed chilly air mist cooling was much longer than with dry and flood coolant when cutting the material.

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A Study on the Energy Saving Type Pneumatic System Characteristics (에너지 절약형 공기압 시스템 특성에 관한 연구)

  • Kim, Hyeong-Ui;Kim, Dong-Su;Gang, Bo-Sik;Seong, Baek-Ju
    • 연구논문집
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    • s.25
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    • pp.91-98
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    • 1995
  • Recently, improving the energy efficiency of a pneumatic system and reducing the consumption of compressed air were a concern of scholars at domestic and abroad. The using fields of a pneumatic system are widely used in factory automation of manufacturing line, chemical factories with explosiveness danger and petroleum industries etc. In particular, pneumatic cylinder is applied to feeding work of workpiece. jig tools and press mechanism, reciprocation and rotary motion with rack and pinion. In this study, the experimental apparatus consisted to pneumatic cylinder, dual supply pressure regulator and solenoid valve. The dual supply pressure regulator connected to outlet port of solenoid valve. The supply pressure($4.5kg_f/cm^2$) of compressed air goes into the rodless chamber 1 to drive the piston rod forward which is named working stage. The supply pressure ($2kg_f/cm^2$) of compressed air goes into the rod chamber 2 to drive the piston rod backward which is named no-working stage. Accordingly, the research results of this study can be obtained to Energy-Saving Effects of the compressed air about 35%.

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Cutting Characteristics of Micro grooving by Cutting Environments in High Speed Machining using Ball End Mill (미세홈 고속가공시 절삭유제 공급방식에 따른 가공성 평가)

  • 배정철;정연행;강명창;이득우;김정석
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.172-175
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    • 2002
  • High speed machining is one of the most effective technologies to improve productivity. It can give great advantage for manufacture of die and Moulds. However, when machining of micro groove in high speed machining a severely thermal damage was generated on workpiece and cutting tool. Generally, the cutting fluid is used to improve penetration. lubrication. and cooling effect. In order to rise the performance of lubrication. it contains extreme pressure agents (Cl, S, P). But the environment of work room go bad by those additive. Therefore, the compressed chilly air with oil mist system was developed to replace the conventional cutting fluid system. This paper carried out the tests to evaluate the machinability by the cutting environment in high speed micro groove machining of NAK80 (HrC40). Compressed chilly air with oil mist was ejected on the contact area between cutting edge and workpiece. The effect of this developed compressed chilly air with oil mist system was evaluated in terms of tool life. The results showed that the tool lift of carbide tool coated TiAlN with compressed chilly air mist cooling was much longer than that of the dry and flood coolant when cutting the material.

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A Comparison of the Cooling Effects for the Compressed Cold Air and Coolant on the Cylindrical Grinding with WA Wheel (WA 숫돌을 이용한 원통 연삭 시 압축냉각공기와 연삭유의 냉각효과에 관한 연구)

  • Lee, Seok-Woo;Choi, Hon-Zong;Jeong, Hae-Do
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.10
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    • pp.155-161
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    • 2000
  • Recently, environmental pollution has become a big problem in industry and many researches have been done in order to preserve the environment. In the grinding process, the coolant has great influence on environment. It contains several chemicals(sulfur, phosphorus and chlorine) to improve the grinding efficiency. If these additives go into the workplace atmosphere, it is harmful for workers. It can also cause the environment pollution. Because of these reasons many studies have been done to minimize the amount of coolant. However the small amount of coolant can cause the thermal defect on the ground surface layer. This study forced the effects of the compressed cold air when the spindle shaft materials(SCM4 & SCM21) were cylindrical ground with WA wheel. The compressed cold air was used as the coolant and grinding performance was compared with that of the conventional grinding fluids(emulsion). Many experiments were carried out with these two cooling materials. The surface roughness, residual stress, and roundness were measured for the cylindrical grinding. The test results showed that the compressed cold air was very useful as the cooling materials for grinding process. It was also efficient to minimize the thermal defects of workpiece and could also play a role in solving environmental pollution.

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Stability Analysis of Concrete Plugs Installed in Pilot Tunnels for the Storage of Compressed Air (압축공기 저장용 파일롯 터널에 설치된 콘크리트 플러그의 안정성 해석)

  • Lee, Youn-Kyou;Song, Won-Kyoung;Park, Chul-Whan;Choi, Byung-Hee
    • Tunnel and Underground Space
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    • v.20 no.6
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    • pp.446-454
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    • 2010
  • CAES-G/T (Compressed Air Energy Storage - Gas Turbine) power generation is a likely option for the buffer facility stabilizing the fluctuation of the renewable powers, such as wind and solar powers. Considering the geological conditions, the underground CAES facility is most probable if the CAES-G/T generation is planed in Korea. In this kind of facility, a concrete plug is installed to seal the compressed air in the container, so that the selection of the shape and dimension of concrete plug could be a critical design factor. The stability evaluation of two types of plug was carried out by investigating the distribution of the factor of safety in the plugs and the distribution of contact pressure over the contact surface. The analysis result shows that the taper-shaped plug is more structurally stable than the wedge-shaped plug for the given geological condition. Possible separation of the rock-concrete interface around the spring line of the wedge-shaped plug is anticipated, which means the possible leakage of compressed air through the side wall and also means the poor mobilization of frictional resistance on that area.

Analysis of Cooling Effect Using Compressed Cold Air in Turing Process (압축냉각공기를 이용한 선삭가공시 냉각효과 해석)

  • Kwak, Seung-Yong;Kim, Dong-Kil;Lee, Jong-Hang;Lee, Sang-Jo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.6
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    • pp.1007-1013
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    • 2003
  • As environmental restriction kas continuously become more strict, machining technology has emphasized on development of environment-friendly technology. In cutting technology, it has been well recognized that cutting fluids might have undesirable effects on workers health and working environment. In this study, compressed cold air was used as a replacement for conventional cutting fluids. The cooling effect on cutting tool was analyzed using the finite element method and the computational fluid dynamics. This study focused on the temperature simulation of cutting tool by real flow analysis of cold air. The maximum flow rate and the minimum temperature of compressed cold air are 300ι/min and -30$^{\circ}C$ respectively. To compare the simulation and experimental results, inner temperature of the cutting tool was measured with the thermocouple embedded in the insert. The results show that the analysis of cutting temperature using FEM and CFD is resonable, and the replacement of cutting fluid with cold air is available.

Evaluation of the Energy Efficiency of the Air Engine (공기 엔진의 에너지 효율 평가)

  • Park, Jaehyeon;Baek, Jehyun
    • Transactions of the Korean Society of Automotive Engineers
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    • v.23 no.5
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    • pp.494-501
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    • 2015
  • Nowadays, many people are trying to develop eco-friendly engines such as the electric motor and the air engine because the I.C. engine cause a lot of pollutants. Nevertheless of these effort, there are few evaluation and comparison of these engines to conventionally used I.C. engines. Because of this, it is difficult to determine that the eco-friendly engines are really energy saving engines. In this paper, the efficiency of the air engine is calculated. The air engine does not cause environmental pollution problem because it uses "Compressed air". Due to the air engine operated at a low temperature and spark-free condition, this engine can be used in extreme condition for safety. Despite the many advantages of the air engine, there are few analysis on the air engine because of an air engine is low energy density.

Thermodynamic Energy Balance Analysis of Underground Lined Rock Caverns (LRC) for Compressed Air Energy Storage (CAES) (복공식 지하 압축공기에너지 저장공동의 열역학적 에너지수지 분석)

  • Kim, Hyung-Mok;Park, Do-Hyun;Ryu, Dong-Woo;Choi, Byung-Hee;Song, Won-Kyong
    • Tunnel and Underground Space
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    • v.21 no.4
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    • pp.297-306
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    • 2011
  • In this paper, we performed thermodynamic energy balance analysis of the underground lined rock cavern for compressed air energy storage (CAES) using the results of multi-phase heat flow analysis to simulate complex groundwater-compressed air flow around the cavern as well as heat transfer to concrete linings and surrounding rock mass. Our energy balance analysis demonstrated that the energy loss for a daily compression and decompression cycle predominantly depends on the energy loss by heat conduction to the concrete linings and surrounding rock mass for a sufficiently air-tight system with low permeability of the concrete linings. Overall energy efficiency of the underground lined rock caverns for CAES was sensitive to air injection temperature, and the energy loss by heat conduction can be minimized by keeping the air injection temperature closer to the ambient temperature of the surroundings. In such a case, almost all the heat loss during compression phase was gained back in a subsequent decompression phase. Meanwhile, the influence of heat conductivity of the concrete linings to energy efficiency was negligible.

Performance Evaluation of Compressor to Develop 500W Class Ultra-Micro Gas Turbine (500W급 초소형 가스터빈 개발을 위한 압축기 성능 평가)

  • Seo, JeongMin;Park, Jun Young;Choi, Bum Seok;Park, Moo Ryong
    • The KSFM Journal of Fluid Machinery
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    • v.15 no.6
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    • pp.51-57
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    • 2012
  • Performance evaluation of a compressor is conducted to develop 500W class ultra-micro gas turbine (UMGT) for power generation. The performance evaluation is essential to check the performance of the components of UMGT, a radial turbine, a centrifugal compressor, an angular combustor and a shaft, which have been already designed in previous researches. The purpose of this study is to introduce the development process of the performance testing equipments of the UMGT and to present the results of compressor performance test. For the performance evaluation of the compressor, two test equipments are developed and the initial test equipment uses commercial static air bearings with long shaft. In the improved test equipment, static air bearing is improved to increase rotating speed and compressed nitrogen gas is used for utility gas of the static air bearing to supply compressed air in a stable and steady way. To increase rotating speed to 320,000 rpm, 80% speed of design speed, compressed air is provided to the turbine. The performance map of the compressor with the 50%, 60%, 70%, 80% speed of design point is presented. The results of the performance test of compressor show a good agreement with the results of 3D CFD.

A Study on the Environment-Friendly Grinding Technology through Minimizing Coolant (냉각액 최소화를 통한 환경 친화적 연삭 가공기술 연구)

  • 최헌종;이석우;김대중;정해도
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.05a
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    • pp.796-799
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    • 2000
  • The concern of environmental problems by using coolant required the recycling technologies of used coolant and development of environmental-firiendly coolant Some methods have been developing. Those are the dry grinding with compressed cold air and grinding with misted coolant. The farmer is effective in the cooling effect, but has not the performance of lubrication. Otherwise, the latter can satisfy both of them and also decrease the environmental pollution. This paper tried to analyze the cooling effect and surface integral of coolant, compressed cold air, mist through measuring the temperature of grind point and grinding force. Especially, the grinding method with misted coolant according to parameters was done. So, the finding method with misted coolant proved to be effective as one of methods to decrease the environmental pollution.

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