Investigation on micro deep drawing process of stainless steel 316 and 430 foils

Abstract

Deep drawing process is one of the most widely used forming processes in industries to produce aerospace components, automotive components and consumer products. From the last decade, due to rapid development in the field of microelectronics and micro-electro-mechanicalsystem, the demand for micro parts has continuously increased. When compared with other forming processes, the micro deep drawing process is extensively used to produce micro components in greater quantities. The micro deep drawn components of circular and rectangular shapes made from stainless steel foils are being used as resistor end caps, transistor caps, fuse end caps, sensor outer body, vibration motor body of mobile phones etc., The quality of deep drawn parts and the deformation behaviour of the sheet metal depend on tooling, materials and process parameters. Hence the optimization of forming parameters is an important task to reduce manufacturing cost and improving the quality of products. In this research work, the investigations are carried out by conducting micro deep drawing experiments using stainless steel 316 and 430 grade foils with a different thickness of 100,200 and 300µm. The influence of foil thickness, size of the cup, tooling parameters, lubrication and grain size on the maximum punch load, variation in cup thickness, LDR, radial and hoop strains are analysed. The deformation behaviour of foils is also characterized. To optimize the process parameters in the micro deep drawing process, Taguchi technique combined with the Grey relational analysis is used. Three levels input parameters for punch corner radius, die corner radius, friction, and clearance have been used to conduct the experiments. Analysis of Variance (ANOVA) is used to find the significance of these parameters based on output responses. The mechanical properties of stainless steel 316 and 430 foils are determined from tensile and anisotropic tests. The grain size and surface roughness of the foils are also determined. To investigate the formability of selected foils, the geometrically scaled micro deep drawing experiments are conducted. The Finite Element (FE) simulation software ABAQUS 6.10/standard is used to model and analyse the micro deep drawing process for different tooling and process parameters conditions. newline