Die-less fabrication of miniaturized parts through single point incremental micro-forming

Abstract

In recent years, demand for miniaturized products has significantly increased in biomedical and micro-electronics industries. In this article, a relatively new sheet forming technique named incremental sheet micro-forming (μISF) is comprehensively investigated to address the emerging need for micro-manufacturing. Using μISF, a metal foil is deformed into complex three dimensional shape by navigating a hemispherical-tip tool over it in a pre-defined toolpath. Experiments are conducted using 50 μm thick AL 1100-O and AL 5052-H19 foils on a table-top numeric controlled machine coupled with force transducer. Measured force data reveal a cyclic nature in axial direction with fluctuations close to 13% that is unprecedented in macro-scale metal parts. This fluctuation can be attributed to either heterogeneous material deformation due to high grain size to thickness ratio or planar anisotropy. The subsequent analysis provides insight into extent of geometric accuracy and enhanced material formability obtained in μISF process. Also, a novel defect is detected due to feature twisting that is never observed in macro-scale parts while forming pyramid shaped geometry. The developed setup is proved to obtain reliable and repeatable results and validates that μISF can provide good alternative for flexible manufacturing of miniaturized products.