• Title/Summary/Keyword: Thermal compensation

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Simulation Research on the Thermal Effects in Dipolar Illuminated Lithography

  • Yao, Changcheng;Gong, Yan
    • Journal of the Optical Society of Korea
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    • v.20 no.2
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    • pp.251-256
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    • 2016
  • The prediction of thermal effects in lithography projection objective plays a significant role in the real-time dynamic compensation of thermal aberrations. For the illuminated lithography projection objective, this paper applies finite element analysis to get the temperature distribution, surface deformation and stress data. To improve the efficiency, a temperature distribution function model is proposed to use for the simulation of thermal aberrations with the help of optical analysis software CODE V. SigFit is approved integrated optomechanical analysis software with the feature of calculating OPD effects due to temperature change, and it is utilized to prove the validation of the temperature distribution function. Results show that the impact of surface deformation and stress is negligible compared with the refractive index change; astigmatisms and 4-foil aberrations dominate in the thermal aberration, about 1.7 λ and 0.45 λ. The system takes about one hour to reach thermal equilibrium and the contrast of the imaging of dense lines get worse as time goes on.

Characteristics Evaluation of Spindle Thermal Displacement with kinds of Lubrication Oil (윤활유 종류에 따른 주축 열변위의 특성 평가)

  • 강순준;이갑조;김종관
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2003.04a
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    • pp.93-98
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    • 2003
  • High speed precision machines have been introduced to the CNC industry in order to improve productivity, shorten the appointed date of delivery and reduce the prime cost. High speed machines have more functions then general machines, and they were proved in performance. The production and sales of the high speed machines have been increased not only in domestic market but also all over the world. Accordingly, machines are faster, there are lots of problems to be solved. One of the most difficult problems is the thermal displacement on the main spindle due to generated heat while the spindle is rotated in high speed. Since the thermal displacement directly effects the quality of the machined parts, utmost efforts to minimize the thermal displacement have to be given from the beginning of designing machines. In practice, variety of methods are attempted and practiced to minimize the thermal displacement such as design of symmetrical frame, adoption of high speed bearings, application of compensation system using non-contact sensor and use of forced circulating lubrication system with oil cooler. Even if these variable methods have been practically used in the industrial field, generated heat has not been Perfectly Prevented lienee, in this paper, the characteristics of thermal displacement were investigated when several kinds of oil were tested for a high speed machine with forced circulating lubrication system within the same atmosphere and under the same conditions.

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Characteristics Evaluation of Spindle Thermal Displacement with kinds of Lubrication Oil (윤활유 종류에 따른 주축 열변위의 특성 평가)

  • 강순준;이갑조;김종관
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.2
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    • pp.47-53
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    • 2004
  • High speed precision machines have been introduced to the CNC industry in order to improve productivity, shorten the appointed date of delivery and reduce the prime cost. High speed machines have more functions then general machines, and they were proved in performance. The production and sales of the high speed machines have been increased not only in domestic market but also all over the world. Accordingly, machines are faster, there are lots of problems to be solved. One of the most difficult problems is the thermal displacement on the main spindle due to generated heat while the spindle is rotated in high speed. Since the thermal displacement directly effects the quality of the machined parts, utmost efforts to minimize the thermal displacement have to be given from the beginning of designing machines. In practice, variety of methods are attempted and practiced to minimize the thermal displacement such as design of symmetrical frame, adoption of high speed bearings, application of compensation system using non-contact sensor and use of forced circulating lubrication system with oil cooler. Even if these variable methods have been practically used in the industrial field, generated heat has not been perfectly prevented. Hence, in this paper, the characteristics of thermal displacement were investigated when several kinds of oil were tested for a high speed machine with forced circulating lubrication system within the same atmosphere and under the same conditions.

A Study on Thermal Deformation Compensation in the Molding of Aspheric Glass Lenses (비구면 유리렌즈 열변형 보정에 관한 연구)

  • Lee, Dong-Kil;Kim, Hyun-Uk;Cha, Du-Hwan;Lee, Hak-Suk;Kim, Hye-Jeong;Kim, Jeong-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.5
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    • pp.22-26
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    • 2010
  • Recently, due to the tremendous growth of media technology, demands of the aspheric glass lens which is a high-performance and miniaturized increase gradually. Generally, the aspheric glass lens is manufactured by Glass Molding Press (GMP) method using tungsten carbide (WC) mold core. In this study, the thermal deformation which was occurred by GMP process was analyzed and applied it to compensate the aspheric glass lens. The compensated lens was satisfied that can be applied to the actual specifications.

Development of Error Compensation System and On the Machine Measurement System for Ultra-Precision Machine (초정밀가공기용 오차보상시스템 및 기상측정장치 개발)

  • 이대희;나혁민;오창진;김호상;민흥기;김민기;임경진;김태형
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.599-603
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    • 2003
  • This paper present an error compensation system and On-Machine Measurement(OMM) system for improving the machining accuracy of ultra-precision lathe. The Fast-Tool-Servo(FTS) driven by a piezoelectric actuator is applied for error compensation system. The controller is implemented on the 32bit DSP for feedback control of piezoelectric actuator. The control system is designed to compensates three kinds of machining errors such as the straightness error of X-axis slide, the thermal growth error of the spindle. and the squareness between spindle and X-axis slide. OMM is preposed to measure the finished profile of workpiece on the machine-tool using capacitive sensor with highly accurate ruby tip probe guided by air bearing. The data acquisition system is linked to the CNC controller to get the position of each axis in real-time. Through the experiments, it is founded that the thermal growth of spindle and tile squareness error between spindle and X-axis slide influenced to machining error more than straightness error of X-axis slide in small travel length. These errors were simulated as a sinusoidal signal which has very low frequency and the FTS could compensate the signal less than 30 m. The implemented OMM system has been tested by measuring flat surface of 50 mm diameter and shows measurement error less than 400 mm

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Analysis of Longitudinal Steel Behaviors of Continuously Reinforced Concrete Pavement at Early Age (연속철근콘크리트(CRCP) 종방향 철근의 초기거동 분석)

  • Nam, Jeong-Hee;Jeon, Sung Il
    • International Journal of Highway Engineering
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    • v.16 no.6
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    • pp.59-67
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    • 2014
  • PURPOSES : The purpose of this study is to analyse the longitudinal steel strain and stress of continuously reinforced concrete pavement(CRCP) with longitudinal and transverse direction at early age using stress dependent strain analysis method. METHODS : To measure the longitudinal steel strain, 9-electrical resistance and self-temperature compensation gauges were installed to CRCP test section (thickness = 250mm, steel ratio = 0.7%) and continuously measured 10min. intervals during 30days. In order to properly analyze the steel stress first, temperature compensation process has been conducted. Secondly, measured steel strains were divided into stress dependent strain (elastic strain) and stress independent strain (thermal strain) and then stress dependent strain was applied to stress calculation of longitudinal steels. RESULTS : Steel strains were successfully measured during 30days. To verify the accuracy of temperature compensation process, measured coefficient of thermal expansion(COTE,$11.46{\times}10^{-6}m/m/^{\circ}C$) of longitudinal steel before paving was compared with that of unrestrained steel. Max. steel stress in the transverse direction shows about 266MPa at 23days after placement. CONCLUSIONS : Steel stresses in the longitudinal and transverse direction have been evaluated. In longitudinal direction, steel stress from the crack was rapidly reduced from 183MPa at crack to 18MPa from 600mm apart the crack. From this observation, stress effective length can be identified as within 600mm apart from the crack. In transverse direction, max. stress point was located near the center of pavement width and stress level(266MPa) is about 66% of yield stress of steel.

Effect of the Reactive Power Compensation System on Performance Enhancement in a 900 MW Combined Cycle Power Plant (무효전력보상장치 설치가 900 MW 복합화력발전소의 성능향상에 미치는 효과)

  • Lee, Young Ok;Yoo, Hoseon
    • Plant Journal
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    • v.17 no.2
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    • pp.48-53
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    • 2021
  • In the case of a 900 MW combined cycle power plant, most of the load on the site is a rotating device and is operated at a low power factor, and the power factor decrease increases the reactive power, which causes the efficiency of the device to be consumed and unnecessary unnecessary power consumption. This study intends to present the results by installing and operating a reactive power compensation device that absorbs and removes reactive power, which is a solution to this problem, on a 6.9 kV on-board bus. As a result of application of this system, first, it was confirmed that the power factor of the rotating machine was improved to 0.22 and the load power in the house was reduced by 1.4%, and the thermal efficiency of the generator was increased by 0.1% and the power generation power by 810 kW. Next, it was confirmed that the cost of construction and operation can be reduced in the future due to economic feasibility, with a decrease of 200 million won/year in electricity loss compared to 1.5 billion won in investment, an increase of 1 billion won/year in sales, and a one-year capital recovery period.

Measurements of Thermal Expansion Coefficients in GRP Pipe (GRP 복합관의 열팽창계수 측정)

  • Oh, Jin-Oh;Yoon, Sung-Ho
    • Composites Research
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    • v.25 no.1
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    • pp.26-30
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    • 2012
  • This study was focused on the measurement of thermal expansion coefficients for GRP pipe through strain gage circuits. First of all, thermal expansion coefficients of aluminum beam were measured to examine the validity of the suggested method by using various types of strain gage circuits. Thermal expansion coefficients of GRP pipes along axial and hoop directions were measured to investigate the effect of the location of strain gages, number of repeated measurements, and strain gage types with different thermal expansion coefficients on the thermal strains and the repeatability of measured results. According to the results, thermal expansion coefficients of GRP pipes along hoop direction were lower than those along axial direction due to the constraint effect of reinforced glass fibers on thermal strains along hoop direction. As measurements were repeated, thermal expansion coefficients of GRP pipes were slightly increased, but the degree of increase became smaller. Finally, the same thermal expansion coefficients were obtained irrespective of different types of strain gages with different thermal expansion coefficients if thermal strains of strain gages were compensated by using reference compensation specimen.

Non linearity Distortion Cancellation Module Design for Thermal Noise Compensation (열잡음 보상을 위한 비선형 왜곡제거 모듈 설계)

  • HwangBo, Chang;Ko, Young-Eun;Bang, Sung-Il
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.27-30
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    • 2005
  • In this paper, we designed and manufactured the distortion cancellation module which is able to compensate thermal-noise distortion by software The distortion cancellation algorithm not only bring forth system non-linear distortion by input level but also bring compensate component of distortion by thermal to get rid off distortion from now on. After TMS320C6711 DSP to recognize our algorithm, we manufactured the module for every kinds of system To evaluate efficiency of the distortion cancellation module, we designed and manufactured communication system. By measured result, if system output power is -3dBm equally, 12dB of ACLR has improved in 1MHz away from a center frequency, and also gain has increased up to 0.5dB.

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The Design of Power Amplifier using Temperature Memory Effect Compensation (열잡음 메모리 효과 제거기를 이용한 전력증폭기의 효율 개선)

  • Ko, Young-Eun;Lee, Ji-Young
    • The Journal of Information Technology
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    • v.10 no.3
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    • pp.47-58
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    • 2007
  • In this paper, we designed and manufactured the distortion-cancellation module which is able to compensate thermal-noise distortion by software. The distortion-cancellation algorithm not only bring forth system non-linear distortion by input level but also bring compensate component of distortion by thermal to get rid off distortion from now on. After TMS 320C6711 DSP to recognize our algorithm, we manufactured the module for every kinds of system. To evaluate efficiency of the distortion-cancellation module, we designed and manufactured communication system. By measured result, if system output power is -3dBm equally, 12dB of ACLR has improved in 1MHz away from a center frequency, and also gain has increased up to 0.5dB.

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