System and methods for producing a deep drawn cup

Abstract

An apparatus for forming a deep drawn cup can include a double die that is adapted to form a cup shape and iron a wall thickness of the drawn cup in a single operation.

1 . An apparatus for deep drawing a metal blank into a deep drawn cup having a cup sidewall thickness T FC , a cup inner diameter D FC , and a cup height H FC , the apparatus comprising:
 a top die comprising a bore opening having a tractrix profile region and a first draw line downstream of the tractrix profile region as viewed from a first end of the opening to a downstream second end of the opening, wherein the tractrix profile region has a tractrix curvature configured based on the outer diameter of the metal blank and outer diameter of the to be formed cup;   a bottom die positioned immediately downstream of the top die and spaced a predetermined distance from the top die, the bottom die comprising:
 a draw die having a bore opening having a second draw line, wherein a second draw line diameter D DL2  is smaller than a first draw line diameter D DL1 , and 
   a die holder into which the draw die is press fit, the draw die holder having a bottom surface having a profile substantially the same as a profile of a bottom of the cup to be formed; and   a punch for applying a pressure to the metal blank to draw the metal blank into the top and bottom dies, wherein when the punch applies a pressure to the metal blank, the metal blank is drawn into the bore opening of the top die along the tractrix profile region and the first draw line to produce an intermediate cup, and then the intermediate cup is further drawn into the bore opening of the draw die and deformed along the second draw line thereby forming the deep drawn cup, wherein a first ironing of a sidewall thickness occurs as the metal blank is drawn through the first draw line and a second ironing of a sidewall thickness occurs as the intermediate cup is drawn through the second draw line, and wherein:   a ratio of a diameter of the punch to a diameter of the metal blank (P D :C D ) is about 0.28 to about 0.64,   the predetermined distance is measured as a distance between an upstream-most edge of a length of the first draw line and an upstream-most edge of a length of the second draw line, and   the predetermined distance is about 59% to about 78% of a theoretical height of the intermediate cup H C .   
     
     
         2 . The apparatus of  claim 1 , wherein a surface of the punch has a tapered profile. 
     
     
         3 . The apparatus of  claim 1 , wherein a vertical wall of the draw die holder includes a vertical taper between 0.5 and 1.0 degree. 
     
     
         4 . The apparatus of  claim 1 , wherein the punch is a cylindrical shape. 
     
     
         5 . The apparatus of  claim 1 , wherein the punch comprises an air passageway having at least one opening on a bottom surface of the punch and at least one opening along a side wall of the punch. 
     
     
         6 . The apparatus of  claim 1 , wherein a diameter of the punch is substantially same as the cup inner diameter D FC . 
     
     
         7 . The apparatus of  claim 1 , wherein the first draw line diameter D DL1  is determined by D DL1 =P D +2(0.85T TC ), where P D  is a diameter of the punch and T TC  is a theoretical maximum thickness of a sidewall of a forming cup exiting the tractrix profile region. 
     
     
         8 . The apparatus of  claim 1 , wherein the first draw line length L DL1  is determined by L DL1 =1.2*T TC , where T TC  is a theoretical maximum thickness of a sidewall of a forming cup exiting the tractrix profile region. 
     
     
         9 . The apparatus of  claim 7 , wherein T TC  is 1.22 times a thickness of the metal blank. 
     
     
         10 . The apparatus of  claim 1 , wherein the second draw line diameter D DL2  is determined by D DL2 =P D +(2T FC ), where P D  is a diameter of the punch and T FC  is the sidewall thickness of the cup. 
     
     
         11 . The apparatus of  claim 1 , wherein the second draw line length L DL2  is determined by L DL2 =1.4*T IC , where T IC  is a thickness of the intermediate cup. 
     
     
         12 . The apparatus of  claim 11 , wherein T IC  is 85% of a theoretical maximum thickness of a sidewall of a forming cup exiting the tractrix profile region T TC . 
     
     
         13 . The apparatus of  claim 12 , wherein T TC  is 1.22 times a thickness of the metal blank. 
     
     
         14 . The apparatus of  claim 1 , wherein the first draw line irons a thickness of the forming cup about 15% to about 33%. 
     
     
         15 . The apparatus of  claim 1 , further comprising a blank locator ring to hold the metal blank when the punch engages with the metal blank. 
     
     
         16 . The apparatus of  claim 1 , wherein bore opening of the draw die as a first taper region upstream of the second draw line and a second taper region downstream of the second draw line. 
     
     
         17 . The apparatus of  claim 16 , wherein the first taper region has an about 3° outward taper and the second taper region has an about 1.5° outward taper. 
     
     
         18 . The apparatus of  claim 1 , wherein the bore opening of the top die has a taper region downstream of the first draw line. 
     
     
         19 . The apparatus of  claim 18 , wherein the taper region has an about 1.5° outward taper. 
     
     
         20 . An apparatus for preparing an opening of a deep drawn cup for welding, comprising:
 a base for receiving the deep drawn cup, the base having a receiving area having a shape substantially matching the shape of the deep drawn cup, wherein the base has one or more sidewalls surrounding the deep drawn cup when the deep drawn cup is placed in the receiving area, the one or more side walls having a height between 0 to 24% of the thickness of the sidewalls of the deep drawn cup remains extended above the sidewalls; and   a smash die for applying pressure to a top edge of the deep drawn cup sufficient to flatten the top edge, wherein the smash die has a substantially planar die surface for engaging with the top edge of the cup and a width wider than a diameter of the cup.   
     
     
         21 .- 38 . (canceled)