An energy-based surface flattening method for flat pattern development of sheet metal components

Sheet metal parts are widely used in various industry branches. The flat pattern development of sheet metal components is a prerequisite for sheet metal fabrication. The conventional graphic solution or the analytical method carried out manually is laborious, time-consuming, and lacks accuracy. The feature-based flattening could help to achieve the objective of automatic pattern generation; however, it is only suitable for bend formable sheet metal components composed of flat and simple curved surface. Inspired by its wide applications in cloth and shoemaking industries, the energy-based flattening for mesh surface is then introduced into the flat pattern derivation of sheet metal parts in this paper. A simplified energy model is proposed as our physical model. An innovative energy relaxation process based on variable step size is introduced to promote efficiency. Some key issues like seed triangle selection and overlap correction are also concerned. For those complex surfaces, a hierarchy flattening methodology is proposed to release the flattened distortions. A comparison between the energy method and the classic as-rigid-as-possible mesh parameterization is made to show the effectiveness of our method. The numerical experimental results show that the energy-based flattening method is a practical, intelligent, and automatic approach for flat pattern generation of sheet metal components.