Drawability of Functional Corrugate Cup Using Roller Die

The formability of the corrugated cup was investigated by the deep drawing process. Deep drawing, which is one of press forming, is a plastic processing technology for forming a thin plate into a three-dimensional container or case. For container products, there are many products formed by this technology. Depending on the application, the functionality of the container itself was required. For example, there are embossing, thickening, and tailored blanks processing. In the present study, corrugated cup was formed to enhance the functionality of the cup. A unique die was used to form the cup having a corrugated shape. The shoulders of the die were grooved, and the steel balls were arranged without gaps in the groove. The balls rotated freely during forming. In an experiment, the blanks were commercially extra-low carbon steel SPCC and stainless steel SUS304. The initial diameter and thickness of the blank were 70 to 95 mm and 0.3 to 0.5 mm. The lubricant was the solid powders of molybdenum disulfide. The deep drawing process was performed using an oil hydraulic press at a forming speed of approximately 10 mm/min. The diameter of the punch was 40 mm, and the smallest hole diameter of the die was 41 mm. These tools were tool steel SKD11, and were standard heat treated. The metal sheets were successfully drawn without the cracks. In the side wall of the cup, the distance between the waves was approximately 8.6 mm. The thickness strain at the bottom of the drawn cup SPCC was no more than 0.1.