Lubricating oil-less deep drawing assisted by water pressure

摘要

The utilization of water pressure as an environmental-friendly lubrication technology is investigated. Specifically, instead of lubrication oil, water is utilized as the pressure medium for hydraulic counterpressure deep drawing (HCP) method and radial-pressure-assisted hydraulic counterpressure deep drawing (RHCP) method. In the cylindrical deep drawing of A5182 and SUS304 sheets, the two methods can yield a higher limiting drawing ratio than the conventional method of applying high-viscosity lubricating oil. In particular, by utilizing a water pressure of 10 to 15 MPa, the RHCP method achieves as high a limiting drawing ratio for the above two types of material as the conventional method of applying high-viscosity lubricating oil. When a press with a small outer slide capacity is used, the HCP method yields a higher limiting drawing ratio than the RHCP method, because the former can produce a higher water pressure than the latter. When a press capable of applying water pressure suitable for a drawn material is used, however, the RHCP method yields a higher limiting drawing ratio than the HCP method. The reason is that the former has the effect of pushing flange ends and of decreasing the friction between the blank and the blank holder.