My ICMSAO’11 paper has been published in IEEE Xplore

Numerical Simulation based Optimization of Die Compensation for a Front Side Member in Sheet Metal Forming

There has been a growing interest during the past decade in using finite element methods for springback prediction. Microprocessors have become more powerful and faster for many software applications which are trigger the development of wide computational software based on finite element. Springback simulation has been well verified by many computations that both accuracy and robustness can be guaranteed with validation setting. Accommodation of springback distortion is the last steps of numerical simulation of sheet metal forming, consequently, any calculation errors resulting from previous simulation will be influence this analysis. This paper present and discussion numerical simulations procedure of die compensation by combined two methods of Displacement Adjustment (DA) and Spring Forward (SF). Both are based on comparing the deformed shape with the desired target. Surface generator is applied to create a new die surface which will be used in the next iteration. DA and SF are combined in one algorithm with the robustness of DA and steadily of SF method were applied simultaneously in the compensation simulation. Finally, an accurate compensated die surface is presented which is generated from the new approach.

Combined Method of Spring-forward and Spring-back for Die Compensation Acceleration

The most key factor in the modern sheet metal process is an accurate dimension of final shape part. The accurate simulation of the drawing products will not be useful since springback will occur after the tools are removed off the drawing die set. One of the most promising ways to solve this problem is modifying the die surface as known die compensation. Die compensation is one of the hottest topics in the stamping field.
In this paper, a new method to compensate the die tool shape due to elastic deviation is proposed. The combination of spring-forward and spring-back method is applied simultaneously. This method was applied to 2D draw bending benchmark problem from Numisheet ’93 for verification. The simulation result shows that the final deformed part is closely to the desired shape part.

Finite Element Simulation

An accurate modelling of the sheet metal deformations including the springback prediction is one of the key factors in the efficient utilisation of Finite Element Method (FEM) process simulation in industrial application. Assuming that springback can be predicted accurately, there still remains the problem of how to use such results to appear at a suitable die design to produce a target part shape. It is this second step of springback compensation that is addressed in the current work. This paper presents an evaluation of a standard benchmark model defined as Benchmark II of Numisheet 2008, S-channel model with various drawbeads and blank holder force (BHF). The tool geometry modified based on springback calculation for a part to compensate springback. The result shows that the combination of the smooth bead with BHF of 650 kN resulted in the minimum springback and the tool compensation was successfully to accommodate the springback errors.