Abstract:
The problems commonly found during a Deep Draw Process are the avulsion and wrinkle by the blank holder force. If blank holder force is too much high, it may cause the avulsion of material. On the contrary, the strain of material likely to occur when small blank holder force is applied. To control the flux of steel sheet, a varying (decreasing or increasing) applied force method has been proposed. However, such method is not capable to control the flux in specific area of steel sheet. Thus, the method called as Draw Bead has been suggested, in which the flux of steel is blocked by a small bar.
This research study was aimed at the Haft-Round drawbead, V-Shaped and Trapenzifrom were used. The studied variables were the influences of blank holder force at 30 percent, 50 percent and 70 percent. The material used were Cold Rolled Steel Sheets grade SPCC, SPCD and SPCE which affected to the material flow to opened die. Deep Draw Process was done by using different shapes of draw beads, the blank holder force with different pressures and with the use of different kinds of materials. Then the results were compared to the result of Finite Element - simulation. The findings revealed that the studied parameters, such as shape of Draw Bead, blank holder force and material type, were strongly influent to the material (steel). As revealed by the experimental results, the work piece at the blank holder force of 50 percent, Haft-Round Draw Bead and SPCE material could provide a good condition for flux in the steel sheet. In addition, the experimental results were compared with the simulation results obtained from a Finite Element method. It was found that the difference (of any point of comparison) between experimental and simulation results were 7.4% (as average). It can be concluded that the Finite Element method can effectively forecast, and can be used as a guideline for shape improvement of draw bead in Deep Draw Process.