The forming of flat sheets of material to a curved form through bending is used in widespread applications. Not only core materials of multilayer composites, but also single material sheets are processed with this technique.In this publication we will investigate a method known as KERF. As current methods are using a grid of slits from border to border in linear or crossing configuration, the authors are presenting a method with slits based on surface curvature. The bespoke slits can be straight or curved and must not be from border to border of the sheet-material. Depending on the curvature, the slits can cross or self-intersect. The method is applicable for developable and with limitations for non-developable surfaces.In this paper the authors will describe their method of surface analysis and pattern generation on a given target surface. First the slit pattern is generated on a 3D Nurbs-surface and subsequently mapped to a developed or approximated two dimensional equivalent of the surface. As the current objective of the investigation is the generation of double curved panels for architectural applications, the resented surface types have four corners and more or less planar boundary curves that connect them. Although other surface boundaries as e.g. continuous curves are also possible. This limitation is also advantageous for the curvature analysis and Slit generation based on UV-Directions.The authors will show a 3D-Slit generating algorithm, where material depth, tool properties and material constraints will define position and density of curve network. The consecutive step of mapping this pattern to a 2D-flat equivalent of the surface with the help of UV Information, will also be clearly described. The 2D-flat equivalent can either be a developed surface generated from the original 3Dsurface or an approximated on with the boundary first method.In the fabrication process the slits may either have a fixed rectangular cross section, or a V-shaped cross section that allows a constant material cross section in 3d bent state. Based on the material and the chosen slit-cross section, the authors will discuss two different fabrication processes. The first one is based on a CNC-milling process for rectangular slits, while the second one generates V-shaped slits with a 6R industrial robot. 
The authors will also describe the forming process and its related constraints&nbsp;for both strategies with two different materials as wooden sheet material and PET-foam sheets. The limits of the strategy depending on machine dimensions, tool size and process-tolerances, will be shown and explained.&nbsp;

Double Curved Panel Forming With Bespoke Slits

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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