یک الگوریتم جدید برای کاهش تعداد مراحل تشکیل فشار در فرآیندهای فشرده سازی با استفاده از بهینه سازی های عددی و شبیه سازی FE

This study presents a new simulation-based technique for the optimum design of a multi-stage forging process aiming at reduction of the number of press-forming stages. This iterative design technique involves response-surface-based numerical optimization and a finite element analysis of the process. The design procedure starts with an initial process design that is deemed too conservative, i.e. allows to arrive at the desired product but involves an excessive number of stages. To obtain a better process design, one stage of the existing multi-stage process is eliminated using numerical optimization in conjunction with an FE simulation. This is repeated by reducing the number of stages one by one until the minimum possible number of stages is reached. This design technique is applied to stage reduction of a three-stage forging process of an axisymmetric aluminum billet. It is confirmed that a new two-stage process design is obtained successfully and the developed design optimization technique showed its effectiveness in reduction of the number of press-forming stages in a multi-stage forming process.

Many metal parts of complex shape are formed by a multi-stage forging process. Reduction of the number of press-forming stages is the most efficient approach for the reduction of manufacturing costs and time. Therefore, it is very important to determine the optimum multi-stage process design which has the minimum number of press-forming stages. Optimization of the process design can be achieved by eliminating redundant stages and optimizing working conditions including tool design for every press-forming stage. In current practice such process improvement is performed mainly using a trial and error experimental approach that requires long time and high cost. Nowadays, numerical optimization based on the finite element analysis offers a better choice. Although several researchers applied numerical design optimization for various plastic forming processes [1], [2], [3], [4] and [5], such optimization procedures are not applicable to the problem of reduction of the number of stages in a multi-stage process. Another numerical approach to a multi-stage process design is an application of numerical simulation linked to a knowledge-based system [6]. However, such system entirely depends on a sufficient amount of data available in advance. In this study, we propose a new technique for a multi-stage forging process design specifically aiming at the reduction of the number of stages. It arrives at the optimum process design using response-surface-based numerical optimization and finite element analysis of the process without relying on an existing database. This design technique has been applied to a problem of reduction of the number of stages in a three-stage axisymmetric forging process of aluminum billet [7] and [8] demonstrating its effectiveness for the improvement of a multi-stage forging process.

A new design optimization technique for the reduction of the number of stages in a multi-stage forging process is proposed. The design procedure starts with an existing forging process design. To eliminate one stage in the multi-stage process, the new optimum process design is determined based on the existing process design using numerical optimization in conjunction with an FE simulation. This design optimization step is repeated, reducing the number of stages one by one, until the minimum possible number of stages is reached. The developed design technique is applied to the stage reduction of a three-stage forging process. It is confirmed that the optimum two-stage process design is obtained successfully and the developed design technique is an effective tool for the reduction of the number of stages in a multi-stage forging process. It is envisaged to apply this technique to other metal forming processes such as multi-stage deep drawings.