A Novel Algorithm for Thickness Prediction in Incremental Sheet Metal Forming

Abstract

Incremental sheet metal forming characterized as increased flexibility and local plastic deformation is well suitable for low-production-run manufacturing and a new sample trial production of complex shapes. Thickness thinning is still an obstacle to the application of incremental forming. In this study, a novel mathematical algorithm based on a non-uniform rational B-spline (NURBS) surface was proposed and implemented which focuses on predicting and calculating the final thickness for arbitrary parts in incremental forming. In order to evaluate the validity of the proposed model, the finite element simulation and forming experiments of three kinds of parts, such as truncated cones, truncated pyramids and ellipsoid parts, were conducted. The thickness of theoretical prediction was compared with that of finite element simulation and experiment, and good agreements were obtained. The results show that the proposed model and the method are effective and robust for predicting the thickness of the formed parts in incremental sheet metal forming.

Finite Element Simplifications and Simulation Reliability in Single Point Incremental Forming

“…Moreover, cyclic loading and unloading of the workpiece during the SPIF process also increase the residual stresses, which amplify the springback effect and overall geometric inaccuracy. In addition to the careful selection of the process parameters, elastic springback can be minimised by global or local heating of the workpiece before and/or during the process [ 20 ].…”

“…The FEM simulations of metal-processing technologies are often implemented in industrial practice prior to the part production [ 19 , 20 , 21 , 22 ]. However, for process optimisation, they are often not effective enough due to long computational time, modelling complexity, and insufficient accuracy of the simulated part [ 18 , 19 ].…”

“…In order to perform the simulations in the shortest possible time, the explicit dynamic types of solvers are mostly employed for FE simulations of the SPIF. With this, shorter computing times in comparison to the implicitly based solvers can be attained [ 20 ]. Furthermore, to additionally shorten the computational time, several approaches based on different simplifications in the process modelling have been suggested.…”

Investigation of Surface Roughness in Incremental Sheet Forming of Conical Drawpieces from Pure Titanium Sheets

“…Elastic springback may occur after the release of the drawpiece from the forming device and after the tool is released. The residual stresses arising during the cyclic loading and unloading of the SPIFed component increase the springback effect and geometric inaccuracy [22]. The third type of geometric inaccuracy of the incrementally formed components arises at the beginning of the ISF process.…”

Shape Accuracy in Single Point Incremental Forming of Conical Frustums from Titanium CP2 Sheets

“…The workpiece material and tools are less loaded compared to conventional deepdrawing processes. SPIF has the following advantages (Li et al, 2017;Murugesan et al, 2022;Wang et al, 2022): low force resulting from the incremental character of the process, high flexibility of the process makes it possible to quickly and easily take into account design changes in shaped elements, a conventional CNC machine can be used to carry out the process, the process does not require stamping dies. SPIF has also some disadvantages: requires a longer forming time than a conventional sheet forming process, the process is limited to prototyping and small production batches, poor surface finish.…”