Importance

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Abstract

New technology for deep drawing can bodies for use in the manufacture of two-piece cans for food and beverage products from precoated flat-rolled sheet metal can stock in which damage to can stock precoated on both surfaces with an organic coating is avoided and draw-forming of the side wall is controlled to decrease metal requirements. A draw die cavity entrance (47, 74) is selected to provide at least a major portion of its curvilinear surface having a radius of curvature of about five times nominal sheet metal thickness gage, or less, e.g. a maximum radius of curvature of 0.04 inch is used for the more commonly used can stock materials. During cup redraw, nesting of curvilinear clamping surfaces (21, 26) of the prior art is eliminated; the compound curvilinear juncture of a work product cup, between its end wall and side wall, is reshaped about a clamping ring compound curvilinear transition zone (72) of smaller surface area than the cup juncture and, the sheet metal is clamped solely between planar clamping surfaces (63, 71) during redraw to a smaller diameter utilizing a male punch (66) with a punch nose (79) having a significantly larger surface area than that of the cavity entrance zone.

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First Claim