Non-rigid Registration: A Powerful Morphing Tool in SPIF Process Planning

Abstract

The flexible nature of the Single Point Incremental Forming process implies that it is well-suited for small batch production and rapid prototyping of complex sheet metal parts. To overcome the process limits and to improve the accuracy, methods that alter the tool paths used to generate the part, like multi-step tool paths or compensated tool paths, have proven their effectiveness. However, their practical implementation in the production of complex freeform parts is not straightforward. Part of the challenge lies in deforming the geometric models without compromising the integrity of the surfaces. When using STL models, offsetting the surfaces often introduces anomalies like intersecting facets and flipped surface normals. This paper explores the use of Non-Rigid-Registration based morphing to produce regular and smooth STL surfaces. This is a technique used in medical imaging to identify anatomical correspondences between different meshes or images acquired, used to compare different images (one subject) or study anatomical variability (multiple subjects). The adaptation of the technique is explained and its use is demonstrated in the automatic generation of multi-step and compensated surfaces.