• 한국공작기계학회논문집
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• 제18권2호
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• pp.194-200
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• 2009

The extruder type is classified as screw type and non-screw type in terms of the extrusion method. The screw type extruder, which is the most frequently used, is classified as the single screw extruder and the multi-screw extruder. They are classified as vertical type and horizontal type in terms of structure; and those for compounding and for forming in terms of function. The single screw extruder is a universal extruder, most of which is suitable for the extrusion forming of thermoplastic resin. The multi-screw(two-screw, three-screw and four-screw) extruder can increase the extrusion power using the engagement of the screw flank. The single screw extruder does not have a good mixing ratio of the raw material and stable extrusion power, while it has low construction cost and operation cost. In this study, the single screw extruder, which has many weak points compared with the multi-screw extruder, was studied. There have been many studies on the single screw extruder, and they led to its significant development. The existing study method, however, had complex analysis processes and required much time. In this study, the CFD was applied to the performance test and analysis of the extruder, and the optimal design condition of the extrusion power for the screw and die of the single screw extruder was found by comparing the analysis results with the actual performance measurement of the single screw extruder.

• 한국생산제조학회지
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• 제25권6호
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• pp.452-457
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• 2016

Single screw compressors are widely used in the fields of air/gas compression, refrigeration, and chemical fluid transportation systems. A single-screw compressor is composed of a screw rotor and two gate rotors located at both sides. This simple construction enables low rotational speed of the rotor, efficient compression with low noise, low vibration, and long bearing life. Despite these merits, the design method of single-screw compressors is not well known. To accelerate the industrial application of single-screw compressors, a design method using coordinate transformation is presented in this paper, and a tool trajectory is established for machining. Finally, the screw rotor, which is machined using the proposed method, is presented.

• 대한조선학회 특별논문집
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• 대한조선학회 2008년도 특별논문집
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• pp.84-89
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• 2008

Twin screw mode LNG Carrier is appeared. Because LNG CARRIER is larger recently. In this paper introduces maneuvering characteristics of Twin screw LNG CARRIER on single screw mode, which are found when the non-using screw mode is fixed or not(wind mill).

• Korea-Australia Rheology Journal
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• 제18권3호
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• pp.143-151
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• 2006

We analyzed the non-Newtonian and non-isothermal flow in a single screw extruder system and investigated the mixing performance with respect to the screw speed and the screw pitch. The viscosity of polymer melt was described with Carreau-Yasuda model. The mixing performance was computed numerically by tracking the motions of particles in the screw element system. The extent of mixing was characterized in terms of the deformation rate, the residence time distribution, and the strain. The results revealed that the high screw speed reduces the residence time but increases the deformation rate while the small screw pitch increases the residence time. It is concluded that the high screw speed increases the dispersive mixing performance and the small screw pitch increases the distributive mixing performance.

• 대한의용생체공학회:의공학회지
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• 제42권1호
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• pp.1-6
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• 2021

Recently, various types of pedicle screws have been developed considering the anatomical structure of the spine. The purpose of this study was to evaluate the pullout stiffness and strength of two types of commercial pedicle screws. The design of two type screws were single pitched thread (ST) pedicle screw and dual pitched thread (DT) pedicle screw, respectively. The tests were conducted in accordance with the ASTM standards using polyurethane (PU) test blocks which has anatomical structure of the spine. There was no significant difference in pullout stiffness between two types of screw. However, DT exhibited higher pullout strength than ST (p<0.05). Pedicle screw with dual pitched thread showed higher pullout strength without decrease in pullout stiffness compared to the standard pedicle screw. In conclusion, dual pitched thread design of the pedicle screw is considered to be more suitable than the single pitched thread for the anatomical structure of the spine.

• Korea-Australia Rheology Journal
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• 제21권4호
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• pp.289-297
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• 2009

We numerically analyzed flow characteristics of the polymer melt in the screw equipment using a proper modeling and investigated design parameters which have influence on the mixing performance as the capability of the screw equipment. We considered the non-Newtonian and non-isothermal flow in a single rotor equipment to investigate the mixing performance with respect to screw dimensions as shape parameter of the single rotor equipment and screw speed as process parameter. We used Bird-Carreau-Yasuda model as a viscous model of the polymer melt and the particle tracking method to investigate the mixing performance in the screw equipment and considered four mixing performance indexes: residence time distribution, deformation rate, total strain and particle standard deviation as a new mixing performance index. We compared these indexes to determine design parameters and object function. On basis of the analysis results, we carried out the optimal design by using the response surface method and design of experiments. In conclusion, the differences of results between the optimal value and numerical analysis are about 5.0%.

• 대한의용생체공학회:의공학회지
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• 제39권3호
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• pp.134-139
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• 2018

One of the most common problems with pedicle screw system is pullout of the screw. This study was performed to evaluate the pullout strength and driving torque of newly designed pedicle screws. The design of three type screws were standard pedicle screw, which had single lead threaded and single pitched design (Type A), single pitched and dual lead threaded pedicle screw (Type B), dual pitched and dual lead threaded pedicle screw (Type C), respectively. The tests were performed in accordance with the ASTM standards using polyurethane (PU) foam blocks. There was no significant difference in pullout strength among three types of screw. Type B and Type C exhibited higher insertion torque and removal torque than Type A, respectively (p<0.05). Pedicle screws newly developed with dual pitched and dual lead threaded design showed higher driving torque without decrease in pullout strength compared to the standard pedicle screw and could be inserted more rapidly with the same number of revolutions.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.337-342
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• 2001

A numerical study of three-dimensional fluid flow and heat transfer in the metering section of a single screw extruder has been performed. The mathematical model for the screw channel is simplified by unwound channel and fixing the coordinate system to the screw. The pressure boundary and the prescribed mass flow rate conditions are imposed on the inlet and outlet, respectively. The commercial code STAR-CD based on the finite volume method is used to obtain the results of the present work. The computation of the reverse flow, which cannot be computed by the marching-type 3-D model, is performed in the present study.

• 한국임상수의학회지
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• 제39권1호
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• pp.28-31
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• 2022

A 5-week old Thoroughbred foal was presented with severe left carpal valgus. Radiographs of the dorsopalmar projections confirmed the deviation was 14 degrees. Surgery using a single-position screw traversing the physis of the distal radius was performed. The limb was almost straight (2 degrees) 3 weeks after surgery. Visual/radiograph follow-up 7 months after screw removal revealed no over-correction after removal of the screw. Transphyseal bridging using a single-position screw without lateral periosteal transection of distal radius was successful for the correction of foals with this condition.

• 한국식품과학회지
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• 제15권4호
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• pp.392-398
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• 1983

식품 압출성형기 (Food Extruder)의 기계적 성질과 제품 특성을 이해하기 위하여 다목적 Pilot plant 용 Single-Screw Extruder를 제작하고 corn grits를 사용한 Extrusion-cooking process의 기계적 성질과 제품 특성을 조사 하였다. Start-up 기간에서 스크류우 회전속도에 따른 열 발생속도를 측정하여 다음과 같은 결론을 얻었다. Start-up 기간에서의 열 발생속도는 스크류우 회전속도 및 원료사입속도에 직접적인 영향을 받았다. 추정된 바렐내부에서의 반죽의 점도는 스크류우 회전속도에 크게 영향을 받았으며 이 점도의 변화로 바렐내부에서의 가열 용융반응이 진행되는 정도를 예측할 수 있었다. Start-up 기간에서의 팽화율은 주로 바렐내부의 온도와 열용융 반응이 일어난 정도에 의존하였다. Corn Grits가 호화되는 바렐온도와 탄화가 일어나는 온도는 회전속도에 따른 체재시간에 크게 영향을 받았다.