• Design & Manufacturing
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• 제2권5호
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• pp.34-38
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• 2008

It was investigated that two rods of aluminium can be welded by hot extru-pressure welding method with stepped welding dies, and that the welding pressure on the welding surface were analyzed by computer simulation according to the stepped shapes of welding dies. It was known by computer simulation that welding pressure on the welding section of rods welded using stepped welding dies. And it was known by experime- nts that two rods of aluminium can be welded on the end sections by hot pressure welding method using stepped welding dies without relative rotational movement of contacted aluminium rods needed for the purpose of friction heating and pressure.

• 소성∙가공
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• 제4권4호
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• pp.322-334
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• 1995

This study presents development of an expert system for process and die design of hot extrusion through square dies. The design of extrusion dies is still an art rathere than a science with increasing complexity of shape and thinness of section. Therefore, most of the die design is still dependent on personal judgement, intuition and experience. The objective of this study is to develop an expert system which includes a rule base system extracted from literatures and experts in the extrusion industry. The system also includes finite element simulation program. The developed system is effectively used to design two types of processes and dies with lead time and trial extrusion.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 춘계학술대회 논문집
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• pp.106-109
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• 2001

The use of ceramic inserts in hot extrusion dies offers significant technical and economic advantages over other forms of manufacture. These potential benefits can however only be realized by optimal design of the tools so that the ceramic inserts are not subjected to stresses that lead to their premature failure. In this paper, process simulation and stress analysis are thus combined during the design, and a data exchange program has been developed that enables optimal design of the dies taking into account the elastic deflections generated in shrink fitting the die inserts and that caused by the stresses generated in the process. The stress analysis of the dies is used to determine the stress conditions on the ceramic insert by considering contact and interference effects under both mechanical and thermal loads. The results are compared with the experimental ones for verification.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.72-77
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• 2001

The use of hexagonal ceramic inserts for copper extrusion dies offers significant technical and economic advantages over other forms of manufacture. In this paper the data on the loading of the tools is determined from a commercial FEM package as the contact stress distribution on the die-workpiece interface and as temperature distributions in the die. This data can be processed as load input data for a finite element die-stress analysis. Process simulation and stress analysis are thus combined during the design, and a data exchange program has been developed that enables optimal design of the dies taking into account the elastic deflections generated in shrink fitting the die inserts and that caused by the stresses generated in the process. The stress analysis of the dies is used to determine the stress conditions on the ceramic insert by considering contact and interference effects under both mechanical and thermal loads.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.764-768
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• 2001

This study presents development of an software for process and die design of hot extrusion through square dies. The design of extrusion dies is still an art rather than a science with increasing complexity of shape and thinness of section. Therefore, most of the die design is still dependent on personal judgement, intuition and experience. The objective of this study is to develop an software system which includes a design rule extracted from literatures and experts in the extrusion industry. The system also includes finite element simulation program. The developed system is effectively used to design extrusion processes and dies with lead time and trial extrusion.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1996년도 춘계학술대회논문집
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• pp.138-144
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• 1996

In square die extrusion, flow guide and ide land play important roles for controlling the metal flow in die design. In the present work, the flow guide and the die land are considered for the die construction. Based on ALE description , rigid-viscoplastic finite element analysid is carried out to assess the effects of process and die design parameters. The thermal state affects greatly the product quality in hot extrusion. in the present work, the temperature distribution is also analyzed in theframwork of rigid-viscoplastic finite element computation. As a computational example, hot square die extrusion with flow guide and die land has been analyzed for the profile of a H section.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.187-191
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• 1995

An experimental study to analyze thd hot extrusion processes of regular square section through square dies is carried out by using plasticine as a model material at room temperature. The experimental setup for the extrusion of squared section from round billets through square dies is designed and manufactured. In order to visullize the plastic flow in the extrusion process the technique of gridding on the planes of the sysmmetries and a stacking the desks with different colors are employed. Velocity fields on the symmetry planes are obtained by using grid distortion.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.436-439
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• 2005

Condenser tube has been used as a component of heat exchanger in automobile and air conditioning apparatus. In this paper, porthole die extrusion that is advantageous to form long hollow section tube is analyzed by direct extrusion of condenser tube with 12 holes. A study on extrusion process is performed through the 3D FE simulation at non-steady state and extrusion experiments. Especially, weldability, extrusion load and die defects were estimated try FE-simulation. This study present the redesigned die of direct extrusion in consideration of the results obtained from FE-analysis.

• 소성∙가공
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• 제6권4호
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• pp.346-356
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• 1997

The fiber orientation distribution and interface bonding in hot extrusion process have an effect on the maechanical properties of metal matrix composites(MMC's). Aluminium alloy matrix composites reinforced with alumina short fibers are fabricated by compocasting method. MMC's billets are extruded at high temperature through conical and curved shaped dies with various extrusion ratios and temperature. This present study was directed to describe the systematic correlation between extrusion die shape and subsequent results such as fiber breakage, fiber orientation and tensile strength to hot extruded MMC's billet. Extrusion load, tensile strength and hardness for variation of extrusion ratios and temperature are investigated to examine mechanical properties of extruded MMC's SEM fractographs of tensile specimens are observed to analyze the fracture mechanism.

• 소성∙가공
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• 제8권5호
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• pp.471-481
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• 1999

The properties of deformed products are generally dependent upon the distribution of microstureture. It is, therefore, necessary to make the distribution of microstureture uniform in order to achieve the best balance of properties in the final product. This is often a demanding task, even for conventional materials. It is become essential to achieving mechanical integrity and a desired combination of microstructure and properties. The objective mechanical integrity and a desired combination of microsttucture and properties. The objective of this study is to design the optimal die profile which can yield more uniform microstructure in hot extruded product. The microstructure evolution, such as dynamic and static recrystallization as well as grain growth, is investigated using the program com-bined with yada and Senuma's empirical equations and rigid-thermoviscoplastic finite element method. The die profile of hot extrusion is represented by Bezier-curve to define all available profile. In order to obtain the optimal die profile which yields uniform microstructure in the product the FPS(Flexible Polyhedron Search) method is applied to the present study. To validate the result of present study the experimental hot extrusion is performed and the result is compared with that of simulation.