Bendability of machined aluminium Tailor-made blanks

Tailor-Made Blanks (TMBs) are sheet metal assemblies that are composed of sheets with different thicknesses and/or materials. Machining is among the techniques that can be used for creation of the needed thickness variations. This paper studies the bendability of machined tailor-made blanks. A high strength aluminium alloy, namely 2024-T3, is selected for the study. Air bending experiments are conducted to determine the minimum bending radius of TMBs with different thickness ratios. It is shown that the production of the machined TMBs with large thickness ratios is complicated by the release of the rolling residual stresses during the machining process. Therefore, the TMBs with large thickness ratios have to be pre-strained prior to the machining process. It is concluded that the minimum bending radius slightly (10-12%) increases as the thickness ratio increases from 1 to 2.The effects of pre-stretching (in a direction in parallel with the bend line) on the minimum bending radius are found to be minimal.