• Title, Summary, Keyword: twin-screw extruder

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Shape Design and Specific Torque Characteristics of the Extrusion Twin Screw (압출용 2축 스크류의 형상설계 및 비토크 특성)

  • 최부희;최상훈
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.8
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    • pp.185-193
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    • 2003
  • The modular self-wiping co-rotating twin screw extruder (SWCOR) has become the most important of twin screw machines. Screw design is one of the most important factors in determining performance of screw extruder. The screw flight and screw channel geometry of SWCOR is determined by the screw diameter, centerline distance, helix angle, and flights number. The maximum allowable throughput rate on a twin screw extruder is determined by a combination of free volume and available specific torque. In this paper we designed geometrical parameters of extruder screw and presented optimal specific torque value in K=1.55, and then developed screw design program for the screw cutting by the use of JAVA API in the twin screw extruder.

Characteristics Design on Flights Shape of the Extruder Screw (압출용 스크루의 날개형상에 대한 특성설계)

  • 최부희;최상훈
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.292-297
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    • 2001
  • Twin screw extruders are the heart of the polymer processing industry. They are used at some stage in nearly all polymer processing operations. This paper is concerned with the basic elements of the extruder design. The proper design of the geometry of the extruder screw is of crucial importance to the proper functioning of the extruder. If the material transport instabilities occur as a result of improper screw geometry, even the most sophisticated computerized control system cannot solve the problem. For this purpose, a characteristic design on flights shape of the extruder screw. This paper presents cross section designs of a closely intermeshing twin screw extruder with double-flighted screw elements, and channel depth characteristics for a double flighted corotating self-wiping twin screw extruder.

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A Study on Screw Design Parameters of Co-Rotating Twin Screw Extruder (동회전 2축 스크류 압출기의 스크류 설계 파라미터에 관한 연구)

  • 최부희;최상훈
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.7
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    • pp.217-226
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    • 2003
  • Twin screw extruders are the heart of the polymer processing industry. They are used at some stage in nearly all polymer processing operations. This paper is concerned with the basic elements of the extruder design. The proper design of the geometry of the extruder screw is of crucial importance to the proper functioning of the extruder. If the material transport instabilities occur as a result of improper screw geometry, even the most sophisticated computerized control system cannot solve the problem. For this purpose, a characteristic design on the screw flights shape of the closely intermeshing co-rotating twin screw extruder. This paper presents design parameters of double flighted screw and triple flighted screw elements, and characteristics of various screw channel area versus screw diameter ratio, K value, in the barrel of screw extruder.

Numerical Study of Internal Flow in Twin Screw Extruder and Its Mixing Performance Analysis (이축 스크루 압출기내 유동의 수치 해석과 혼합 성능 분석)

  • Kim, Nak-Soo;Kim, Hong-Bum;Lee, Jae-Wook
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.1
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    • pp.32-41
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    • 2006
  • We analyzed the non-Newtonian and non-isothermal flow in the melt conveying zone in co-rotating and counter-rotating screw extruder system with the commercial code, STAR-CD, and compared the mixing performance with respect to screw speed and rotating direction. The viscosity of fluid was described by power-law model. The dynamics of mixing was studied numerically by tracking the motion of particles in a twin screw extruder system. The extent of mixing was characterized in terms of the residence time distribution and average strain. The results showed that high screw speed decreases the residence time but increases the shear rate. Therefore higher screw speed increases the strain and has better mixing performance. Counter-rotating screw extruder system and co-rotating screw extruder has the similar shear rate with the same screw speed in spite of different rotating direction. However, the counter-rotating screw has good mixing performance, which is resulted from longer residence time than that of co-rotating screw extruder.

Numerical analysis of internal flow and mixing performance in polymer extruder II: twin screw element

  • Kim, Nak-Soo;Kim, Hong-Bum;Lee, Jae-Wook
    • Korea-Australia Rheology Journal
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    • v.18 no.3
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    • pp.153-160
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    • 2006
  • We analyzed the non-Newtonian and non-isothermal flow with Carreau-Yasuda viscosity model in co-rotating and counter-rotating twin screw extruder systems. The mixing performances with respect to the screw speed, the screw pitch, and the rotating direction have been investigated. The dynamics of mixing was studied numerically by tracking the motions of particles. The extent of mixing was characterized in terms of the deformation rate, the residence time distribution, and the average strain. The results showed that the high screw speed decreases the residence time but increases the deformation rate. Small screw pitch increases the residence time. It is concluded that the high screw speed increases the dispersive mixing performance, while the small screw pitch increases the distributive mixing performance. Co-rotating screw extruder has the better conveying performance and the distributive mixing performance than counter-rotating screw extruder with the same screw speed and pitch. Co-rotating screw extruder developed faster transport velocity and it is advantageous the flow characteristics to the mixing that transfers polymer melt from one barrel to the other barrel.

Tool Shape Design for the Screw Flights Cutting in Twin Screw Extruder (2축 스크류 압출기의 스크류 가공용 공구형상 설계)

  • 최부희;정찬길;최상훈
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.824-828
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    • 2002
  • Twin screw extruders are the heart of the polymer processing industry. The single most important mechanical element of a screw extruder is the screw. The proper design of the geometry of the excluder screw is of crucial importance to the proper functioning of the extruder. If material transport instabilities occur as a result of improper screw geometry, even the most sophisticated computerized control system cannot solve the problem. For this purpose, Tool shape design for the screw flights cutting in twin screw extruder.

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A Study on Machining of the Self-Wiping Co-Rotating Twin Screw (밀폐형 동회전 2축 스크류의 제작에 관한 연구)

  • 최부희;이상혁;최상훈
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1426-1429
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    • 2003
  • This paper describes screw tool design and machining method witch is able to design tool profile and 3-dimensional geometry for screws in self-wiping co-rotating twin screw extruder. The geometric features of screws for co-rotating twin screw extruders are developed from kinematic principles. Closely self-wiping screw segments are manufactured in universal milling machine by using designed screw tools. It is shown that experimental results verified the closely intermeshing condition in twin screw.

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Effect of System Parameters on Target Parameters in Extrusion Cooking of Corn Grit by Twin-Screw Extruder (옥분 압출가공시 이축압출성형기의 System Parameters에 따른 압출물의 특성변화)

  • Kim, Ji-Yong;Kim, Chong-Tai;Kim, Chul-Jin
    • Korean Journal of Food Science and Technology
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    • v.23 no.1
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    • pp.88-92
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    • 1991
  • To analyze the effects of the system parameters on the target parameters, which include the amount of water evaporation, water solubility index(WSI) and water absorption index(WAI), test trials of fractional factorial design of the three process variables at three levels were carried out for corn grit with a laboratory twin-screw extruder with three different screw configurations. The system parameters collected from the trials, such as extrusion temperature, specific mechanical energy input(SME) and mean residence time(RT), were showed the ranges of $129{\sim}182^{\circ}C$, $67{\sim}163\;kwh/ton$ and $12{\sim}34\;sec$, respectively. Within these ranges of the system parameters, the target parameters were able to be quantified by using multiple regression equations. The correlation of results with the system parameters blocked by the screw configuration as dependent variables, yield correlation coefficients above 0.90, and the correlation using the system parameters obtained from whole experiment system as the dependent variables yield correlation coefficients around 0.80. The functional relationship, which can be quantified by second order polynomial regression equation with only two system parameters within necessary degree of accuracy, can he graped in three dimensional surface response and contour diagrams.

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Design Parameters and Conveying Characteristics of Twin Screw Extruder (2축(軸) 압출기(押出機)의 설계요인(設計要因) 및 이송량(移送量)에 관한 분석(分析))

  • Song, D.B.;Koh, H.K.;Kim, Y.H.
    • Journal of Biosystems Engineering
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    • v.19 no.1
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    • pp.50-61
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    • 1994
  • This research was conducted to determine a preliminary design parameters for the development of twin screw extruder using Booy's screw design method, and to analyze a extrusion process using Janssen's mathematical flow model. In processing process, the experimental mass flow rates of com flour and wheat flour were almost the same as theoretical values corrected by correction factors of 0.95 and 0.6 respectively. It was appeared that the mathematical model would be suitable to predict the conveying capacity.

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Analysis of the TPP(Texturization of Plant Protein) Production Process Using Twin Screw Extruder (2축 압출기를 이용한 식물성 단백질의 조직화(TPP)제조공정 분석에 관한 연구)

  • Song, D.B.;Koh, H.K.;Kim, Y.H.
    • Journal of Biosystems Engineering
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    • v.19 no.1
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    • pp.42-49
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    • 1994
  • Texturization of plant protein means the physical or chemical recomposition method of plant protein damaged during the extracting process of soybean oil. As a stable protein supplement, substituted for meat, needs of texturized products have been increased. Twin screw extruder is a very effective tool for texturization process as a physical method. This research, using defatted soy flour as raw material and twin screw extruder manufactured in domestic, showed that plant protein was texturized successfully on the operating conditions of barrel temperature of $120{\sim}140^{\circ}C$, material feed rate of 30~36kg/hr and water content of 20~25%. It also showed that the shape of die affected the texturization continuity.

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