Study On Experimental Techniques Of Microforming

The production of miniature parts is becoming more and more important due to the trend of miniaturization, which is increasingly determining the development of product ranging from mobile phones, computers and micro digital camera to medical products and so on. The application of conventional manufacturing processes for the production of such micro-parts is possible, but there are some problems that result from the small dimensions. During micro-forming materials will behave some characters that are different from normal size processing. Up to now, the systematical research for micro-forming have not come into being. This paper gives a review of the problems associated with miniaturization, and finds the characteristic of micro forming through experiments and finite element analysis.This paper systematically introduces some methods of micro-forming and a universal theory about strain gradient plasticity at present. Research show that metallic materials will display strong size effects when the characteristic length associated with plastic deformation is on the order of microns scale or submicron scale. In order to forecast the size effect in micro forming, strain gradient plasticity has been developed to the micron or submicron regime in recent years, which consider the effect of the intrinsic material length under framework the classical elastic-plastic theory. Though those theories are not so perfect, they will be more practicality with the research being more and more advanced.This paper studied simple tension and microdeep drawing of very thin sheet pure copper and get the mechanical property parameter of shin sheet pure copper. Though experiment method I have studied size effect which when the grain size is same, with the decrease in thickness the yield stress will also decrease gradually. Considering the effect of surface grain, I analyzed theoretically the sort of size effect with classical plastic theory and deduce the calculational formula of yield stress for thin sheet copper under the considering the effect of surface grain size. Compared the result that was educed from the formula with experiment result. It is reasonable to explain the sort of size effect with the surface layer model from the result of compare. Moreover, I have studied the thin sheet copper drawing though experiment and finite element analysis. From the experiment result we can conclude that the formability of the material would be worse and would be easy to be destabilizing.Furthermore, this paper also analyzed the micro-electromagnetic forming and the process of plate drawing under intensive pulse electromagnetic field is simulated and experimented. Established the calculation model of plate drawing load and simulated the current in working coil and the process of plate dynamic response to magnetic force with the software ANSYS.