Prediction and prevention of material cracking in the case of micro or milli drawn parts made from aluminium foils

The micro and milli deep drawings are cold forming processes applied in order to realise micro parts having dimensions smaller than 1.00 mm and milli parts having dimensions between 2–20 mm. Such parts are more and more used in robotics, medical equipment, electronics, etc. In the case of such processes, the small thickness of foils and the small dimensions of parts are the most important factors that influence the process parameters and can affect the quality and integrity of the produced micro/milli parts. The present paper analyses the results of investigations made by experiment and simulation concerning the influence of different factors and the main causes that determine the loss of the material integrity in the case of micro and milli scale cylindrical drawn cups made from thin aluminium alloy foils having thickness between 0.05–0.20 mm. An analytical model that permits the determination of the location and onset of the material cracking and also the optimum process parameters that permit the decrease of the foil thinning in the possible cracking zone and, therefore, to avoid the onset of the parts cracking is also presented in the paper.