Die cavity design of near flashless forging process using FEM-based backward simulation

Abstract Preform design in forging processes is an important aspect for improving the forging quality and decreasing the production cost. Forward and backward simulations of the forging process based on rigid visco-plastic finite element methods (FEMs) can directly provide a preform shape from the final forged shape at a given stage. The objective of this effort is to reduce the material lost as flash by the design of an improved busting operation for a track link forging. This paper uses the FEM-based inverse die contact tracking method to design the preform shapes for a representative plane-strain cross section of the track link blocker forging. This procedure establishes a record of the boundary condition time sequence via forward simulation, using a candidate preform, into the final forged shape. This recorded time sequence is then modified according to the material flow characteristics and the state of die fill to satisfy the requirement of material utilization and forging quality. The modified boundary condition sequence is then applied to control die/node separation during the backward deformation simulation. The backward simulation for the section analyzed provided the blocker preform shape from which the buster dies can be designed. The preform for the section is then evaluated by forward FEM simulation and compared with the results from the original busting operation. Performance measures for the comparison includes die fill, flash size, strain variance, frictional power and die load. Use of round billet stock was also investigated for producing the required preform shape.

[1]  Y. C. Shiau,et al.  Three-dimensional finite element analysis of open-die forging , 1988 .

[2]  Beom-Soo Kang,et al.  Preform design in ring rolling processes by the three-dimensional finite element method , 1991 .

[3]  Ramana V. Grandhi,et al.  A design approach for intermediate die shapes in plane strain forgings , 1991 .

[4]  Raghavan Srinivasan,et al.  Optimum Design of Forging Die Shapes Using Nonlinear Finite Element Analysis , 1993 .

[5]  Ramana V. Grandhi,et al.  Computer aided preform design in forging using the inverse die contact tracking method , 1996 .

[6]  Naksoo Kim,et al.  Preform design in H-shaped cross sectional axisymmetric forging by the finite element method , 1990 .

[7]  Nuno Rebelo,et al.  On the development of a general purpose finite element program for analysis of forming processes , 1988 .

[8]  Edward M. Mielnik,et al.  Metalworking science and engineering , 1991 .

[9]  Ramana V. Grandhi,et al.  Forging preform design with shape complexity control in simulating backward deformation , 1995 .

[10]  T. A. Dean,et al.  A practical computer-aided approach to mould design for axisymmetric forging die cavities , 1985 .

[11]  Naksoo Kim,et al.  Computer-aided preform design in forging of an airfoil section blade , 1990 .

[12]  T. A. Dean,et al.  Computer aided design of die block layouts , 1987 .

[13]  I. Haque,et al.  An empirically based computer-aided design procedure for closed die forgings , 1987 .

[14]  Shiro Kobayashi,et al.  Metal forming and the finite-element method , 1989 .

[15]  Taylan Altan,et al.  Investigation of Defect Formation in a 3-Station Closed Die Forging Operation , 1989 .