Data-Driven Compensation for Bulk Formed Parts Based on Material Point Tracking

Abstract

Currently, common inefficient trial-and-error procedures are used in designing bulk forming dies. Numerous iterations, consisting of numerical simulations and subsequent real tests, are needed to achieve accurate parts. During the compensation cycles, manual redesign in CAD environments is necessary to transform discrete data into parametric descriptions causing approximation errors. Automation of these surface reconstruction processes is barely possible. To address these issues, different data-driven numerical strategies have been deduced based on either displacement or force. In this work, a material point tracking method in forming simulation between die and part geometry is presented. Based on this, enhanced displacement-based and stress-based methods for compensation of bulk forming parts are compared. The convergence behavior of both methods is analyzed with respect to the compensation factor. Finally, the material point tracking approach is validated and verified by compensating a two-dimensional bulk-formed component.

Development of a numerical compensation framework for geometrical deviations in bulk metal forming exploiting a surrogate model and computed compatible stresses

“…A fully geometry-based compensation rule was developed by Hartmann and Eder [27], who succeeded in performing the compensation on a set of user-defined surface points through shape morphing of the nominal geometry [28]. The material point tracking method (MPT) was proposed in the work of Maier [4]. By mapping the tool and part geometry by means of the so-called material points, a deviation-dependent compensation direction can be defined, in contrast to the typical normal or forming directions approaches.…”

“…Although it is common practice in the industry to adapt tool geometry on an experience-driven basis, this results in considerable costs and time overruns. Conversely, it is crucial to dispose of an efficient data-driven strategy for tool geometry assessment in the early design phase, since the dimensional accuracy of the products must be ensured and guaranteed for the whole lifetime of the tools [4]. To this extent, the combination of the forming simulation with a virtual compensation strategy can be successfully employed to simplify the iterative process that leads to optimal tool geometry.…”