Investigation of deep drawing behavior of polymer coated metal sheets

Deep drawing process in manufacturing is a widely used method for giving three dimensional shapes to sheet metals, such as automobile and machine body sheets, white goods, wheel rims, kitchen sinks, kitchenware, medical containers and beverage cans, etc. Deep drawing process is a manufacturing method in which large amount of plastic deformation occurs. Thus, mathematical analysis of deep drawing is extremely difficult due to lots of parameters effective during the process, such as material anisotropy, part geometry, chemical composition of material, environmental conditions, punch speed and effective pressure, etc. It is very important to determine the appropriate blank holder pressure and friction values in order to obtain the highest deep draw ratio without occurrence of damages such as tearing, wrinkling, scratching and earing. In this study, deep drawing process of polymer coated steel sheets was experimentally investigated to reduce friction and increase manufacturing productivity. In the experiments, drawing ratio, blank holder pressure and drawing speed parameters were varied at various intervals and the obtained values were evaluated via graphs. A variety of lubricants are used during deep drawing to reduce the mentioned problems above and to increase product quality. Nevertheless, burning and scratches occur as a result of plastic deformation on the surfaces. Furthermore, it is not always possible to apply some kinds of coatings or paint after manufacturing to a deep drawn product. Coating metal sheets with a polymer based material before the deep drawing process provides a number of advantages such as longevity, decorative appearance, corrosion resistance, prevention of excessive wear, reduction of friction and lubrication need during deep drawing, and removing painting line requirement after forming in some manufacturing methods.