Mechanics-Based Integrated Product and Process Design for Incremental Forming

Abstract

Incremental sheet forming (ISF) is a low cost, die-less forming process suitable for low volume production. In case of components with multiple features, the accuracy of formed component depends on the sequence in which the features are formed. In addition, sheet spring-back, tool deflection, and rigid-body displacement (RBD) also affect the accuracy of formed components. Predicting the component geometry using finite element analysis (FEA) is computationally expensive and time consuming. Simple mechanics-based methodology is presented in this work to predict the geometry of components having single, multiple features, and high-wall angle components formed using single and/or multistage forming. Predictions using proposed methodology are used to select the best forming sequence in case of multiple feature components. Results presented show that the formed component geometry can be predicted with an average error of 225 μm and maximum error of 700 μm. In addition, a methodology is developed to achieve uniform thickness distribution with good accuracy in high wall angle components formed using multistage strategy. Hemispherical component is formed with 100 μm variation in thickness except at the component opening and maximum profile deviation of 350 μm. This thickness prediction capability helps the designer to choose intermediate stages and to form components with engineered thickness with reasonable accuracy.