Preliminary modelling of forming forces in three directions for incremental sheet forming process based on the contact area

摘要

Incremental Sheet Forming (ISF) is a promising forming process for rapid prototype and small batch production of complex 3D shapes due to the enhanced flexibility, increased formability and the reduced forming force. However, the efficient prediction of forming forces in three directions is insufficient, which is critical to achieve the feed-back control and optimization of the process. In this paper, a new method to predict the forming force during the ISF process was proposed. First, the contact stress was obtained by analyzing the theoretical force condition of a unit body within the formed area. Then, the contact area between the forming tool and the sheet was modeled based on experimental examinations. In addition, a forming force prediction model for ISF especially in three directions was established according to actual contact condition and deformation mechanism. Meanwhile, experiments with different process parameters were carried out and a genetic algorithm was used to determine the essential coefficients of the theoretical model. Further, the prediction model of the forming force in three directions in ISF was obtained and the prediction accuracy was verified through extra experiments. The results confirmed that the force prediction has high accuracy and the maximum prediction error of the forming force is below 18%.