Deveopment of rule-based design system for flat die design of hot extrusion process

학위논문(박사) - 한국과학기술원 : 기계공학전공, 2001.2, [ xiii, 146 p. ]한국과학기술원 : 기계공학전공

Method of measuring shear friction factor through backward extrusion process

A method of measuring shear friction factor between a workpiece material and a forming tool through a backward extrusion process. The method includes steps of: positioning the workpiece material at a groove previously manufactured on the forming die by turning; pressurizing the workpiece material to form an extruded product by pressure of a downwardly moving punch; forming tip on the extruded end of the extruded product; measuring an external diameter of the extruded product and a diameter of the tip, and obtaining a perpendicular distance by subtracting the diameter of the tip from the external diameter and dividing the subtracting result by two; and acquiring shear friction factor by calculating predetermined coefficients and a normalized perpendicular distance non-dimensionalized by thickness value of the extruded product. The thickness is defined as an interval between the external diameter of the extruded product and an external diameter of the punch

Development of PC-based Simulation System for Metal Forming

It is well known that the quality and efficiency of the design of metal forming processes can be significantly improved with the aid of effective numerical simulations. In the present study, a two-and three-dimensional finite element simulation system, CAMP form, was developed for the analysis of metal forming processes in the PC environment. It is composed of a solver based on the thermo-rigid-viscoplastic approach and graphic user interface (GUI) based pre-and post-processors to be used for the effective description of forming conditions and graphic display of simulation results, respectively. In particular, in the case of CAMPform 2D (two-dimensional), as the solver contains an automatic remeshing module which determines the deformation step when remeshing is required and reconstructs the new mesh system, it is possible to carry out simulations automatically without any user intervention. Also, the forming analysis considers ductile fracture of the workpiece and wear of dies for better usage of the system. In the case of CAMPform 3D, general three-dimensional problems that involve complex die geometries and require remeshing can be analyzed, but full automation of simulations has yet to be achieved. In this paper, the overall structure and computational background of CAMPform will be briefly explained and analysis results of several forming processes will be shown. From the current results, it is construed that CAMPform can be used in providing useful information to assist the design of forming processes

(Measuring method of shear friction factor usingbackward extrusion)

본 발명은 부피성형 가공시에 압출소재와 금형 사이에 발..