Manufacturers invested in a diverse array of industries, ranging from automotive to biomedical, are seeking methods to improve material processing in an effort to decrease costs and increase efficiency. Many parts produced by these suppliers require forming operations during their fabrication. Forming processes are innately complex and involve a multitude of parameters affecting the final part in several ways. Examples of these parameters include temperature, strain rate, deformation path, and friction. These parameters influence the final part geometry, strength, surface finish, etc. Previous studies have shown that varying the deformation path during forming can lead to increased formability. However, a fundamental understanding of how to control these paths to optimize the process has yet to be determined. Adding to the complexity, as the forming process is scaled down for micromanufacturing, additional parameters, such as grain size and microstructure transformations, must be considered.
In this paper, an analytical model is proposed to calculate strain-paths with one or two loading segments and their associated stress-paths. The model is created for investigations of stainless steel 316L using a microtube inflation/tension testing machine. This machine allows for the implementation of two-segment strain-paths through biaxial loading consisting of applied force and internal pressure. The model can be adjusted, based on the desired forming process or available equipment, to output the appropriate parameters for implementation, such as force, displacement, and pressure.