Experimental and numerical investigations on forming limit curves in micro forming

The Forming limit diagram is an important tool in metal forming processes, as it indicates the failure limits for ductile damage and onsite necking. Forming of micro-thin metal sheets (thickness less than 100 microns) is more difficult and requires more precision. This type of miniaturisation in forming process with the components produced with dimensions up to few millimetres is defined as a micro-forming. There are many differences in the properties of materials and physics of process when macro process is converted to micro. In this work, an experimental test of thin alpha brass sheets of 40 mu m and 90 mu m with different orientations to rolling directions (0o, 45o, 90o) was performed to determine the forming limit curves. Hemispherical punching test designed for micro forming is performed according to ASTM-2218-14 standard test using sample of Uni-Axial, Intermediate Uni-Axial, Bi-Axial, Intermediate Bi-Axial and Plane Strain paths to obtain limit strains. Explicit dynamic numerical analysis with Abaqus platform is used to model micro-forming process and forming limit curves are plotted. Numerical results have been validated with experimental results.

Automated summary

The Forming Limit Diagram is a crucial tool in metal forming processes, as it determines the failure limits for ductile damage and necking. Micro-forming, which refers to the miniaturization of forming processes with components produced in dimensions up to a few millimeters, presents different material properties and physics compared to macro processes. In this study, an experimental test was conducted on thin alpha brass sheets of different thicknesses and orientations to determine the forming limit curves. The numerical analysis using the Abaqus platform validated the results obtained through experimentation.