Improving the deep drawing process without a blank holder using simultaneous corrective ironing: An experimental study

In this experimental research, the process of deep drawing of circular metal sheets was confined without blank holder, and a coincidental method of ironing was applied to improve the quality of the piece of the form. A test bench and a sheet metal drawing device were constructed and made to observe the impact of various parameters on the drawing behavior with the help of a conical die. The emphasis of the study was to determine how the corrective ironing ratio and mechanical properties of the sheet metal affected the effects on various engineering characteristics such as, the cup wall hardness, distribution of the wall thickness and the homogeneity index of the drawn cups. The findings have shown that the application of deep drawing in the absence of a blank holder and concurrent corrective ironing have brought about a high level of enhancement to the surface texture and mechanical characteristics of the respective end product. Nonetheless, it was noted that excessive ironing ratio may render tearing of the cups especially at the initial stages of forming process. Comparison of cups with and without corrective ironing was carried out. The dimensions of the cup were tested according to the wall thickness, the total height and the occurrence or absence of cracks or other defects on the surface. The results obtained indicated that combined correction through ironing and proper adjusting of the clearance of the punch-die resulted in manufacture of cups with more proper dimensions and height of usability.