• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.100-107
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• 2002

The extruder screw is a part for extruding material in a injection molding machine. The screw's geometrical shape can mathematically be described by a sweep surface which is constructed by sweeping a section curve composed of a few circular arcs, along a helical guide curve. In the paper we developed a dedicated CAD system which basically is parametric in a sense that the system initially takes several design parameters to construct the geometric elements including the final sweep surface of the screw as well as section & guiding curves, along with feasibility check of the input parameter values, without further user interaction. The system has been developed as a built-in module onto a commercial CAD system, which can further incorporate additional NC-out functions with ease.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.143-150
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• 1978

In our previous report (Korean J. Food Sci. Technol., 9, 123. (1977), functional properties of soyprotein isolates prepared from defatted soybean meal were studied. Using those properties soyprotein fibers, which may be acceptable as meat analogs, were prepared with protein spinning apparatus. Soyprotein can be converted into the suitable form for the spinning by denaturation with alkali (0.6%) and continuous fibers were spun by extruding spinning solution into an 20% NaCl-1 N acetic acid coagulating bath. The process for producing soyprotein fibers on a bench scale was described and break strength, break elongation and textural parameters of the fibers formed were evaluated. The possible scheme of formation of soyprotein fibers was discussed.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.1
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• pp.89-95
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• 1995

The efficient use as a protein source for poultry of full fat soybean (FFSB) treated under various processes, i. e. steaming under pressure 40 lbs/sq. inch for 5, 10 or 15 minutes or roasting in a baking oven at $180^{\circ}C$ for 20, 30 or 40 minutes or extruding was compared with that of soybean meal. Eight hundred straight run broiler chicks (AA 707) were randomly allotted into 8 treatments of 4 replicates, fed with, rations containing either kind of the above mentioned FFSB for 6 weeks (Wks 1-7). The protein content of the diets for chicks during 1-3, 3-6 and 6-7 weeks of age was 21, 19 and 17% respectively. The result revealed that steaming can destroy 76-92% of the trypsin inhibitor activity (TlA) in soybean, particularly that at 15 minutes, while roasting can get rid of only 13-28% TlA. Chicks fed roasted FFSB had an enlarged pancreas and showed inferior performances to the steaming and the extrusion products. Steaming should be at least 10-15 minutes in order to obtain the comparable performances to those of the extrusion or of the soybean meal. The extruded FFSB showed the best feed conversion ratio. This might be due to the very fine particle of the product.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.335-340
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• 2005

A study on the variation of combustion characteristics by injector geometries was conducted. Coaxial swirl injectors were used. Existence of swirl chamber and variation of a nozzle length become key parameters. Injectors were identified as open, closed and mixed type by existence of swirl chamber. Variation of nozzle length was made extruding the both nozzle along the axis while other design parameters remain the same. A uni-element combustor with ablative material liner and a water cooled nozzle made by oxygen free copper with outer stainless steel casing were used.

• Journal of Korea Foundry Society
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• v.21 no.2
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• pp.119-126
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• 2001

Al/15%Gr. composite have been manufactured by mixing, compacting, and extruding aluminium powder and graphite powder. Then, Al-6%Si/x%Gr., Al-12%Si/x%Gr., and Al-18%Si/x%Gr.(x: 0, 2, 4, 6, 8) composites have been manufactured by remelting the extruded materials(Al/15%Gr.), Al-33.3%Si alloy, and Al ingot, etc. We conducted experiments to chracterize the microstructure, and damping properties and hardness. The result of microstructure experiment on Al-x%Si/y%Gr. composites reveals the good dispersion of graphite. As to Al-Si/y%Gr. composites, the more the graphite contents, the less the tensile strength. And the tensile strength varied according to contents of Si: with its highest value in Al-18%Si/y%Gr. composites and lowest in Al-6%Si/y%Gr. composites. As to Al-x%Si/y%Gr. composites, the more the contents of graphite, the more the vibration damping properties. And we can get the highest vibration damping rate in Al-12%Si/y%Gr. composites which matrix structure is an eutectic component.

• Journal of the Korea Institute of Building Construction
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• v.12 no.6
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• pp.586-595
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• 2012

While the extruded cement panel has many advantages compared to drywall, it has limited applicability in buildings due to its low fire resistance. However, an extruded panel in which the fire resistance has been dramatically enhanced through the addition of a-hemihydrate gypsum is expected to become widely applied as a partition wall or interior material for buildings. To ensure its applicability, certain safety requirements for use, such as the leaning load by residents, the impact by indoor articles, and the fire, need to be taken into consideration. The purpose of this study is to review the impact load resistance, horizontal load resistance, and fire resistance as required safety properties for the partition wall and interior materials of the extruded panel that includes a-hemihydrate gypsum. The results of this study show that the impact load resistance of the extruded panel that includes a-hemihydrate gypsum achieves SD grade for industrial buildings, and the horizontal impact load resistance achieves HD grade for public buildings. In addition, it provides fire-resistance for approximately 7 minutes longer than the existing extruded cement panel. Based on this result, it is confirmed the extruded panel incorporating a-hemihydrate gypsum has adequate safety properties for use as partition wall or interior material.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.5
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• pp.91-97
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• 2020

A split-die design for the cold forging of symmetric parts such as those having a hexagonal cross-section is presented in this paper. Parts with a hexagonal cross-section, such as bolt heads and nuts, should be forged with a die that has a hexagonal-shaped hole. A split type die is required to mitigate the buildup of stress concentrations located at the corners of the hexagonal hole. Generally, the insert of a hexagonal die is made by cutting each corner of a cylinder using a hexagonal hole and then combined with the die and shrink-fitted. However, split dies face problems when extruding material at the corners of the hexagonal split die. To address this problem, two types of split dies were evaluated: rounded hexagonal dies and angular hexagonal dies. The effects of the pre-stress ring on the dies were compared and analyzed and results show that using the angular split hexagonal die can extend the lifetime of forging dies.

• Transactions of Materials Processing
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• v.14 no.2 s.74
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• pp.160-167
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• 2005

In the present study about extru-bending of angle product, the bending of extruded angle products with the $'\Lambda'$ section and 'ㄱ', section can be obtained using two extrusion billets by the hot metal extru-bending machine with the two punches moving in the different velocity. The bending curvature can be controlled by the different velocity of billets through the two-hole container. This paper describes simulations and experiments of extru-bending process that can make bending during extruding by the difference of stem velocities. And they are applied to two kinds of dies, that is, one of them is conical dies with symmetry $'\Lambda'$ section and the other one is conical dies with asymmetry 'ㄱ' section. The results of the forming simulation by $DEFORM^{TM}-3D$ and results of experiments show that the bending phenomenon at the die exit during extrusion can be obtained with two extrusion billet by the two stems moving in the different velocity. And it was known that it is possible to design the structure of conical cavity of extrusion dies and to control the curvature of product through the simulation and experiment of extru-bending process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.3
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• pp.1-7
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• 2020

Fused filament fabrication (FFF) is a process extruding and stacking materials. PLA materials are one of the most frequently used materials for FFF method of 3D printing. Polylactic acid (PLA)-based materials are among the most widely used materials for FFF-based three-dimensional (3D) printing. PLA is an eco-friendly material made using starch extracted from corn, as opposed to plastic made using conventional petroleum resin; PLA-based materials are used in various fields, such as packaging, aerospace, and medicines. However, it is important to analyze the mechanical properties of theses materials, such as elastic strength, before using them as structural materials. In this study, the reliability of PLA-based materials is assessed through an analysis of the changes in the linear elasticity of these materials under thermal degradation by applying a hyperelastic analytical model.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.173-180
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• 2004

The tread pattern of a tire has an important effect on tire performances such as handling, wear, noise, hydroplaning and so on. However, a finite element analysis of a patterned tire with detailed tread blocks has been limited owing to the complexity of making meshes for tread blocks and the huge computation time. The computation time has been shortened due to the advance in the computer technology. The modeling of tread blocks usually requires creating a solid model using a CAD software. Therefore it is a very complicated and time-consuming job to generate meshes of a patterned tire using a CAD model. A new efficient and convenient method for generating meshes of a patterned tire has been developed. In this method, 3-D meshes of tread pattern are created by mapping 2-D meshes of tread geometry onto 3-D tread surfaces and extruding them through tread depth. Then, the tread pattern meshes are assembled with the tire body meshes by the tie contact constraint. Residual aligning torque and frictional energy are calculated by using a patterned tire model and compared to the experimental results. It is shown that the calculated results of a patterned tire model are in a good agreement with the experimental ones.