Research On Size Effect In Micro Blanking Of SUS304 Stainless Steel Foil

With the rapid development of microelectro mechanical systems, the demand for micro-parts are more and more urgent in the industry, miniaturization of the products faces higher precision requirements for forming small components. Micro blanking technology as a new plastic processing technology in the processing and manufacturing industry is playing a more and more important role. The product has high precision in size and good quality in the cross section. It has broad application space in the precision electronic instruments, biomedical, and military national defenseThis article forcus on the mechanical properties size effect in micro blanking, the hybrid constitutive model SUS304 stainless steel foil suitable for micro forming is built, using a method combination of simulation and test, micro-blanking is studied, the size effect mechanism in micro blanking is revealed, and on this basis, SUS304 stainless steel foil of micro-blanking process is carried out.Using one-way stretch micro-tensile tests of SUS304 stainless steel foil, the micro tension size effect is studied, introducing the size dependent parameter based on the surface layer model, the hybrid constitutive model of the SUS304 stainless steel foil in micro forming is established.Using ABAQUS/Explicit software, the finite element simulations are carried out for the strip of stainless steel foil micro blanking process, and the affect of test conditions in the strip of micro-blanking process is analysised. The results show that deformation in the strip of micro-blanking process and the distribution of corss section are similar with common blanking process; with the increasing of relative blanking clearance and grain size, the ultimate shear strength in micro blanking decreases; the ultimate shear strength gradually increases with strip width increasing. Through experimental research of micro blanking with the strip of stainless steel foil strip, the same law with simulation results is obtained, which demonstrates that the proposed hybrid constitutive model stainless steel foil is correct, and reveal the size effect mechanism of micro blanking. The analysis results for the quality of cross section indicates that with the clearance increasing or or the blanking speed reducing, the burnish decreases,and the fracture increases; grain size significantly affects the micro blanking process, fine grained material compared with the coarse grained materials, micro blanking stroke curve has better repeatability.Based on the above research, the micro hole with the minimum diameter of 100μm is successful blanked. By Scanning Electron Microscopy and Laser Confocal Microsopy, surface quality and contour accuracy are detected, the results show that the micro blanking technology has the ability to produce the micro-hole parts with the excellent surface quality and the high contour accuracy.