Abstract
When the fine-blanking process is used, secondary grinding or processing can be omitted because the shear surface of fine-blanking parts can achieve almost zero fracture zone requirements. Fine-blanking has the advantages of high precision and high production efficiency. It was originally used on watch parts, but with increasingly refined technology, it has been widely applied in computers, consumer electronics, communication products, and vehicle parts. The primary objective of the fine-blanking process is to reduce the fracture zone depth and die roll zone width. This study used a 2.5mm thick central processing unit (CPU) thermal heat spreader as an example. Finite element analysis software was employed to simulate and optimize the main eight process parameters that affect the fracture zone depth and die roll zone width after fine-blanking: the V-ring shape angle, V-ring height of the blank holder, V-ring height of the cavity, V-ring position, blank holder force, counter punch force, die clearance, and blanking velocity. Simulation analysis was conducted using the L18 (21×37) Taguchi orthogonal array experimental combination. The simulation results of the fracture zone depth and die roll zone width were optimized and analyzed as quality objectives using Taguchi’s smaller-the-better design. The analysis results revealed that with fracture zone depth as the quality objective, 0.164 mm was the optimal value, and counter punch force made the largest contribution of 25.89%. In addition, with die roll zone width as the quality objective, the optimal value was 1.274 mm, and V-ring height of the cavity made the largest contribution of 29.45%. Subsequently, this study selected fracture zone depth and die roll zone width as multi-criteria quality objectives and used the robust multi-criteria optimal approach and Pareto-optimal solutions to perform multi-criteria optimization analysis. The results revealed the optimal fracture zone depth and die roll zone width were 0.239 mm and 1.288 mm, respectively. Finally, the experimental results verified that the fracture zone depth was 0.230 mm and die roll zone width was 1.205 mm. The findings met the industry’s fraction zone depth standard (below 12% of blank thickness) and achieved a smaller die roll zone width.
Numerical Simulation and Optimization of Fine-Blanking Process for Copper Alloy Sheet