• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.309-312
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• 2002

Precision stage is essential device for semiconductor equipments, fiber optic assembly systems and micro machines. In this paper, we develop a piezo-electric inchworm type actuator for long stroke ultra precision linear stages, and implement a controller to interface with commercial motion controllers. It provides fast implementation of precise position control system substituting for rotary motor. In the future, using a laser interferometer as a position sensor, we plan to implement a nano meter precision stage.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.322-327
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• 1997

This paper investigates the effects of shot peening on mechanical properties of SAE 9254, which is a spring steel used for the suspension system of automobiles. Rotary Bending Fatigue test is accomplished and the results are summarized as fellows : 1. The tensile strength and the hardness do not change so much. 2. The layer of highly residual stress is obtained by multi-stage shot peening. 3. The fatigue strength seems to be improved by residual stress. 4. The fatigue strength of un-peened and multistage shot peened material are 425 MPa and 756 MPa, respectively.

• 한국세라믹학회지
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• 제29권6호
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• pp.489-495
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• 1992

The continuous compaction response of zirconia powders prepared by different processing treatments was investigated. Though the yield point could be or not below 1 MPa, the change of slope was always observed at high pressure range around 60 MPa. Powder compaction was mainly governed by second compaction stage and compaction rate was decreased with increasing forming pressure. Rotary vacuum dried powder favored a high compaction density, whereas freeze dried and calcined powders favored an increase in the pressing efficiency. In order to extract more reliable information about powder compaction, it was necessary to use not only compaction response diagram but also compaction rate diagram.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1717-1722
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• 2003

In this paper we developed flip-chip bonder using XY stage, liner-rotary actuator and vision system. We depicted the major parts of the developed flip-chip bonder. Then we discussed several problems and their solutions such as vision and motion control, pick-up module position accuracy, separation of chip from the blue taped hoop, etc. We used a post guide to improve the horizontal positional accuracy against the long arm. Also, we used an ejector module and synchronization technique for easy chip separation from the blue tape.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.917-923
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• 2001

This paper presents the fabrication and testing results of a dual stage microactuator system for fine positioning of magnetic heads in hard disk drives. An electrostatic rotary microactuator was newly designed and fabricated. The microactuator was integrated into the head gimbal assembly of a disk drive system and its dynamic characteristics were investigated. Experimental results show that natural frequency and voltage gain of the microactuator are 4.3 KHz and 25 nm/V and the dual stage microactuator system achieves the tracking accuracy of 30 nm.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.635-641
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• 1994

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 (4.5kgf/cm$\^$2/) of compressed air goes into the rodless chamber 1 to drive the pistion rod forward which is named working stage. The supply pressure(2kgf/cm$\^$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%.

• 한국환경보건학회지
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• 제38권2호
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• pp.151-158
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• 2012

Objectives: Bioaerosols released by treating organic-waste resources cause a variety of environmental and hygiene problems. The objective of this study was to investigate the distribution characteristics of the airborne bacteria emitted from a pig manure composting plant, a principal site for organic-waste resource facilities. Methods: Three types of pig manure composting plant were selected based on fermentation mode: screw type, rotary type and natural-dry type. Each site was visited and investigated on a monthly basis between September 2009 and August 2010. A total of 36 air samplings were obtained from the pig manure composting plants. The air sampling equipment was a six-stage cascade impactor. Quantification and qualification of airborne bacteria in the air samples was performed by agar culture method and identification technique, respectively. Results: The mean concentrations of airborne bacteria in pig manure composting plant were 7,032 (${\pm}1,496$) CFU $m^{-3}$ for screw type, 3,309 (${\pm}1,320$) CFU $m^{-3}$ for rotary type, and 5,580 (${\pm}1,106$) CFU $m^{-3}$ for natural dry type. The screw type pig manure composting plant showed the highest concentration of airborne bacteria, followed by the natural dry type and the rotary type. The ratio of respirable to total airborne bacteria was approximately 40-60%. The predominant genera of airborne bacteria identified were Micrococcus spp., Staphylococcus spp. and Escherichia spp. Conclusion: Monthly levels of airborne bacteria were highest in August and lowest in November regardless of fermentation mode. There was no significant correlation relationship between airborne bacteria and environmental factors such as temperature, relative humidity and particulate matters in pig manure composting plants.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.258-264
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• 2012

The overall aim of this paper is to determine coupling loss factor of welding point between shell and cylinder using loss factor and structural loss factor. For this purpose, two kinds of loss factor were adopted. One is loss factor of each sub structure, another is structural loss factor based on the complex welded or assembled structure. Using these two parameters, it is possible to derive the coupling loss factor which represents characteristic condition of SEA theory. Coupling loss factor of conjunction in complex structure was expressed as power balance equation. The derived equation for a coupling loss factor has been simplified on the assumption of one way (uni-directional) power flow between multi-sub structures. Using these conditions, it is possible to find the equation of coupling loss factor expressed as above two loss factors. To check the effectiveness of above equation, this paper used two-stage application. The first approach was application between simple cylinder and shell. The next was adopted rotary compressor. Rotary compressor has three main conjunctions between shell and internal vibration part. This equation was applied to find out the optimum welding point with respect to reduce the noise propagation. It shows the effective tool to evaluate the coupling loss factor in complex structure.

• 한국정밀공학회지
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• 제29권2호
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• pp.129-138
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• 2012

In this study, three types of large scale multi-tasking machine tools together with core technologies involved have been developed and introduced; a multi-tasking machine tool for large scale marine engine crankshafts, a multi-tasking vertical lathe for windmill parts, and a large scale 5-axis machine tool of gantry type. Several special purpose devices has been necessarily developed for the purpose of handling and machining big and heavy workpieces accurately, such as PTD (Pin Turning Device) with revolving ring spindle for machining eccentric crankshaft pins, hydrostatic rotary table and steady rest for supporting and resting heavy workpieces, and 2-axis automatic swiveling head for high-quality free surface machining. Core technologies have been also developed and adopted on their detail design stage; 1) structural design optimization with FEM structural analysis, 2) theoretical hydrostatic analysis for the PTD and rotary table bearings, 3) box-in-box type cross-rail and octagonal ram design to secure machine rigidity and accuracy, 4) constant spindle rpm control against gravitational torque due to unbalanced workpiece.

• 드라이브 ㆍ 컨트롤
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• 제20권2호
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• pp.31-39
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• 2023

The aim of this study was to measure and analyze engine load factor (LF) according to working conditions (operation type and gear stage) of small agricultural multi-purpose cultivator to estimate the emission of air pollutants. To calculate LF, a torque sensor capable of collecting torque and rotational speed was installed on the engine output shaft and DAQ was used to collect data. A field test was conducted with major operation of a cultivator and tillage operations (plow tillage and rotary tillage). Engine power was calculated using engine torque and rotational speed and LF was calculated using real-time power and rated power. In addition, unified LF was calculated using the weight for each operation and the average LF for each operation. As a result, average LF values at 1.87 and 3.10 km/h by plow tillage were 0.50 and 0.69, respectively. Average LF values at 1.87 and 3.10 km/h by rotary tillage were 0.70 and 0.78, respectively. Furthermore, unified LF calculated in consideration of the weight factor showed a value of 0.65, which was 135% higher than the conventional LF (0.48). Results of this study could be used as basic information for realizing LF values in the field of agricultural machinery.