Research On Micro-blanking And Stamping Composite Molding Technology

With the rapid development of electronic industry and micro-electro-mechanical systems, the demand for micro parts in micro-electronics, micro-mechanical, aerospace, medical device, biotechnology, national defense and military and many other application fields are more and more increasingly. Miniaturization puts forward higher requirements on production cost, processing quality and production efficiency, which has promoted the development of micro forming technology. Micro blanking and micro deep drawing are important plastic processing methods in micro plastic forming technology which have the advantages of low cost, high efficiency, and are very suitable for mass production of micro parts. However, with the applications of micro parts become more and more widely, single micro plastic forming technology can not meet the production requirements of the high quality and high efficiency, thus the research on micro-blanking and stamping composite molding technology is carried out.Aiming at feature structure position deviation and low efficiency in the process of high-precision micro dish-shaped parts, this paper studies on combining micro blanking process with micro deep drawing process, in order to accomplish three processes of shallow hemisphere drawing, punching and blanking in only one blanking stroke, which can reduce the positioning and installation tolerances, processing time and manufacturing cost of mold with multi-step forming, thus decrease position deviation of micro dish-shaped parts’feature structure, so as to achieve high quality and high efficiency way to manufacture micro dish-shaped parts, and easy to ensure the consistency of the part feature size with composite molding process.The unidirectional micro tension tests of T2 copper are done. The size effect in micro plastic forming process has been studied. The results show that the tensile strength and the elongation decrease at first and then increase with the decrease of thickness, which indicate obvious size effect phenomenon.Shallow hemisphere drawing and micro blanking both are highly complex nonlinear problems, using ABAQUS/Explicit to conduct finite element simulations of micro dish-shaped parts’forming process. The influence of blank holder force on micro deep drawing is studied. The results show that there is no difference on thickness variation, and no defects such as wrinkling and rupture, which suggest that we can use the die with a bottom to product good quality dish-shaped parts through one drawing stroke with or without blank holder force. The results of micro blanking process finite element simulations show that deformation and section in micro blanking process are similar to common blanking, section quality is improved due to small blanking clearance; with the decrease of blanking clearance and cutting edge fillet, the blanking force increases, and improper blanking clearance and cutting edge fillet can cause poor quality of the section.On the basis of finite element analysis, forming process parameters are calculated, a micro- blanking and stamping mold is designed, which using polyurethane rubbers to provide forming forces. Key parameters are verified to ensure the forming process is conducted smoothly.