| 摘要 |
Draw processing flat-rolled sheet metal substrate preselectively precoated on each surface with organic coating and draw lubricant into one-piece can bodies ready for assembly into sanitary packs free of any requirement for washing, organic coating or repair of organic coating after fabrication and before such direct usage. Selective organic precoating includes embodying a blooming compound which is made available as draw lubricant responsive to heat and/or pressure of draw forming; also, surface application of a draw lubricant after curing of the organic coating. Combined lubricant on each surface is verified before start of fabricating. Draw-forming of tensile strength sheet metal is controlled over side wall height by clamping solely between planar clamping surfaces and by interruption of draw to establish a flange at the open end of cup-shaped work product. Surface area of the cavity entrance zone for each die is preselected along with curved surface transition zone on draw punch in relation to sheet metal substrate starting gage. Nesting of curvilinear clamping surfaces of the prior art is eliminated during redraw of work product. The curved transition zone of cup-shaped work product is reshaped prior to redraw.
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