Ultrasound Assisted Micro Punching Of Stainless Steel And Amorphous Alloy Sheets

With the further development of products in the direction of miniaturization,the demand for high-precision and high-quality small and micro-parts in various industries is increasing.In the field of micro-punching parts manufacturing,the traditional mechanical forming method has been limited in production and application due to the high processing cost of the micro-die and the difficulty in accurately centering the convex and concave molds.In this paper,a new punching forming method,Ultrasonic Assisted Micro-shear Punching?UMSP?is introduced,which introduces ultrasonic vibration and replaces rigid punch with viscous medium to avoid alignment problems.It can be used to process various shaped holes from micro to macro scale.In this paper,the micro-punching experiments of X10CrNi18-8 stainless steel?DIN standard imported stainless steel?and amorphous alloy were carried out by using UMSP method.The main work of this paper includes:?1?Single hole with dimensions of 300?m,500?m,750?m and Round hole array with dimensions 3x3-300?m were fabricated by using 20?m stainless steel sheet.The micro-punchking experiment of stainless steel sheet was carried out,and the typical morphology of the blanking process was fabricated by cold mosaic method.The cross-section morphology of blanked parts by UMSP method was observed.The experimental results show that the cross-sections parallel to the rolling direction,perpendicular to the rolling direction and between the two show different cross-section characteristics because of the anisotropy of the material in cold rolling state.In addition,the softening effect of ultrasound on the material is also studied.The results show that the punching force decreases by 20%after applying ultrasound.?2?A series of micro-circular holes with a dimension of 300?m-750?m and micro-to macro-scale irregular holes were punched by using Fe₇₈Si₉B₁₃ strips with a thickness of 25?m,Applying the UMSP method to amorphous materials,the results show that the circular holes with diameters of?300?m,?400?m,?500?m,?600?m,?750?m only need to have a punch pressure of 95 MPa.At 86 MPa,64 MPa,57 MPa and 40 MPa,it can be formed in a very short time?0.05 s?with low stress.This is due to the presence of ultrasonic vibration,which causes partial softening of the amorphous alloy,thus enabling the amorphous alloy to Complete low stress forming.The method was applied to five kinds of amorphous alloys such as La₆₀Al₂₀Ni₂₀,La₅₅Al₂₅Ni₅Cu₁₀Co₅,Al₈₆Ni₉La₅,Fe₇₈Si₉B₁₃ and Cu₅₀Zr₅₀.A variety of shaped hole blanks were prepared under low stress conditions,and the wide applicability of the method to amorphous alloys was further verified.