Patent Publication Number: US-9415433-B2

Title: Scrap shape retention

Description:
FIELD OF THE INVENTION 
     The present invention relates to the shape retention of scrap regions of sheet metal parts when the scrap region is severed from the final part. 
     BACKGROUND OF THE INVENTION 
     The stamping industry has been confounded with a problem, in the scrap regions or addendum, of a stamped part becoming jammed in the scrap-trimming and removal mechanisms. When a stamped part is produced, it often has excess regions or scrap regions, known in the industry as the addendum, owing to the shape of the sheet metal blank from which the stamped part is produced. The addendum is formed because of the necessary amount of sheet metal blank material that is required at various locations of the final part due to the depth of the part drawn within the die cavities. Furthermore, in order that complex contours can be achieved in a final stamped part, the addendum is often contoured itself to avoid wrinkling and undesired stretching in the contours of the final part. By providing a transition of the contour into the addendum, imperfections of the stamped part resulting from the stamping process can be maintained in the addendum. The addendum is then subsequently removed and the final stamped part containing the desired contours remains for use in its given application. 
     Springback or recoil is a condition that occurs when flat-rolled metal, such as sheet metal, is cold-worked as is common in the stamping industry. Upon release of the forming force, once the initial stamping is completed, the material has a tendency to partially return to its original shape due to the elastic recovery of the material. Springback is known to be influenced by the tensile and yield strengths of the material as well as by thickness, bend radius and the bend angle of the sheet metal resulting from the stamping process. In deep drawn sheet metal parts, recoil of the addendum, caused by the release of the internal stress of the curvature or contour in the addendum, as the addendum is severed from the final part, is not only a dangerous problem from a workplace safety standpoint, but also it effects the flow of scrap in a high efficiency situation such as an assembly line or mass production parts shop. 
     When the addendum is severed, to form the final part, for example in an assembly line or mass production parts shop situation where the process is likely substantially automated, the scrap region tends to release inconsistently out of the trimming mechanism or scrap cutter on an inconsistent basis and is not released to the proper place and not when the operator desires the scrap to be released from the cutter. The inconsistent release of the scrap from the scrap cutter often causes jams and prevents the scrap from exiting the die via the scrap chute, causing scrap build-up. Furthermore, the inconsistent scrap nesting locations and subsequent build-ups are known to cause damage to the scrap cutter cutting mechanisms as well as damage to the final part in the form of bent or chipped final part edges. 
     In addition to the aforementioned damage to the cutting edges and the final part, inconsistent release of the addendum from the scrap cutter results in long periods of downtime over a given period for the stamping and cutting machinery while a worker must manually remove the scrap jams in the scrap chute and other places as well as replace or repair damaged cutting edges of the scrap cutter. Therefore, it is desirable to develop a system of inhibiting the recoil of an addendum of a stamped part upon severing. 
     SUMMARY OF THE GENERAL INVENTIVE CONCEPT 
     At least one of the needs and objectives that will become apparent from the following description is achieved in an exemplary embodiment which comprises a sheet metal stamping device for stamping a sheet metal part comprising a first die body and a second die body. The first die body and the second die body are in operable communication for forming the sheet metal part from a sheet metal blank. The sheet metal part has at least one scrap region formed therein, where the at least one scrap region that is prone to recoil from a neutral stamped position. Both the first die body and the second die body have one or more complementary elongate bead forming portions located for forming an elongate bead region in the scrap region. The resultant elongate bead-forming regions are configured for the elongate bead to substantially inhibit recoil of the scrap region from the neutral stamped position when the scrap region is severed from the final part. 
     In an exemplary embodiment, the elongate bead forming portion located on the first die body provides a male bead-forming protrusion and the elongated bead-forming portion located on the second die body provides a die escape. 
     In an exemplary embodiment, the male bead-forming protrusion is shorter in length relative to the die escape. 
     In an exemplary embodiment, the elongate bead-forming portions are provided to form a bead about a bend radius of at least one portion of the scrap region. 
     In some exemplary embodiments, the sheet metal blank is provided as cold-rolled steel or aluminum, or other metals, metal alloys and the like. 
     In another exemplary embodiment, a sheet metal stamping device for stamping a sheet metal part, comprising a first die body and a second die body is provided. The first and second die bodies include first and second bead-forming sections respectively for forming at least one shape-retaining bead in a scrap region of an intermediate blank formation. The scrap region is separable from the intermediate blank formation to form a final sheet metal part and the first and second bead-forming sections are configured in order that the shape-retaining bead substantially retains the scrap region in a neutral stamped configuration following separation from the intermediate blank formation. 
     In another exemplary embodiment, a method is provided for substantially retaining the neutral stamped shape of a scrap region when the scrap region is severed from a sheet metal part comprising:
         a) providing a sheet metal stamping device for stamping a sheet metal part; the device comprising a first die body and a second die body in operable communication for forming the sheet metal part from a sheet metal blank; the sheet metal part including at least one scrap region formed therein being prone to recoil from a neutral stamped position; the first die body and the second die body having complementary elongate bead-forming portions located for forming an elongate bead region in the scrap region for substantially inhibiting recoil of the scrap region from the neutral stamped position;   b) providing a sheet metal blank between the first die body and the second die body;   c) stamping the sheet metal part including at least one scrap region; and   d) severing the scrap region from the final sheet metal part.       

     In another exemplary embodiment, a method for substantially retaining the neutral stamped shape of a scrap region when the scrap region is severed from an unfinished part comprising:
         a) stamping a sheet metal blank so as to form the unfinished part;   b) including at least one elongate bead section in the scrap region of the unfinished part, wherein the elongate bead section extends along a region of the scrap region which is prone to recoil, and wherein the elongate bead section is shaped to inhibit the recoil; and   c) severing the scrap region from the unfinished part so as to from a finished part.       

     In some exemplary embodiments, there are provided automotive vehicles and/or automotive vehicle parts made by the methods herein and/or by the devices herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Several exemplary embodiments of the present invention will be provided, by way of examples only, with reference to the appended drawings, wherein: 
         FIG. 1  is a perspective view of a stamping device in a first operative configuration; 
         FIG. 2  is a sectional view along line  2 - 2  of  FIG. 1 ; 
         FIG. 3  is a perspective view of the stamping device of  FIG. 1  in a second operative configuration; 
         FIG. 4  is a sectional view along line  4 - 4  of  FIG. 3 ; 
         FIG. 5 a    is perspective view of an intermediate stamped part formed from the device of  FIG. 1 ; 
         FIG. 5 b    is perspective view of a final stamped part and a scrap region severed therefrom; 
         FIG. 6  is a sectional view along line  6 - 6  of  FIG. 5   a;    
         FIG. 7  is sectional view of the upper and lower dies along line  6 - 6  of  FIG. 5   a;    
         FIG. 8  is a side view of a stamped component of a vehicle with a pair of associated scrap regions; and 
         FIGS. 9 a  to 9 f    are perspective views of additional exemplary components of a vehicle. 
     
    
    
     DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     It should be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted,” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. In addition, the terms “connected” and “coupled” and variations thereof are not restricted to physical or mechanical connections or couplings. Furthermore, and as described in subsequent paragraphs, the specific mechanical, other configurations illustrated in the drawings are intended to exemplify embodiments of the invention. However, other alternative mechanical or other configurations are possible which are considered to be within the teachings of the instant disclosure. 
     With reference to figures, particularly  FIGS. 1 and 3 , there is provided a sheet metal stamping device  10  for substantially inhibiting recoil from a neutral stamped position of a scrap part region. The device  10  has a first die body  12  and a second die body  14 . The first die body  12  and the second die body  14  are in operable communication such that in an open orientation as shown in  FIG. 1 , a sheet metal blank  16  may be inserted into the device  10  between the first and second die bodies  12 ,  14  for a stamping operation to produce an unfinished intermediate sheet metal part or formation  18   a  ( FIG. 3 ). 
     The first and second die bodies  12 ,  14  include complementary regions to form the part. In this case, the first die body includes a male region in the form of a deep drawing protrusion region  20  as is shown in  FIGS. 2 and 4  and the second die body  14  includes a complementary female region in the form of a deep drawing receiving region  22  shown in  FIGS. 1 to 4 . Of course, the deep drawing protrusion and receiving regions  20 ,  22  may be reversed as desired. 
     The deep drawing protrusion region  20  and deep drawing receiving region  22  are provided for stamping a part  18   a  or  18   b  that has complex contours such as those shown, by way of example only, at  28  in the final or finished part  18   b  in  FIGS. 5 b    and  6 . Such complex contours  28 , tend to recoil from a neutral stamped position  30  as in  FIG. 6 , to a recoiled position  32  shown in ghost in  FIG. 6 . 
     Briefly, the following is provided with reference to the figures to further understanding of the invention. The property of recoil or springback is common in cold-rolled steel or aluminum sheet metal stamped parts (or stamped parts from other materials in which recoil may occur) and particularly problematic when an addendum or scrap region  34  is removed from a finished sheet metal part  18   b  as shown in  FIG. 5 b   . The recoiling, for example, tends to lead to the scrap regions  34  releasing inconsistently from the trimming mechanisms in the production of the final stamped part  18   b . Thus, the severed scrap regions  34  tend to inconsistently nest in the scrap cutter equipment (not shown) and cause build-ups which may damage the equipment or lead to production delays. For example, in order to the form the complex contours  28  in a final part  18   b , the complex contours  28  may extend into a scrap region  34  which is to be removed from the final part  18   b . The scrap region  34  may be required to be formed during the stamping process owing to the shape of the final part  18   b  or to serve as “relief regions” to avoid wrinkling or stretching in the contours  28  of the final part  18   b . Thus, a portion of the contour  28  is often formed within the scrap region  34 . When the scrap region  34  is removed, the contour  28  in the scrap region tends to recoil from the neutral stamped position  30  as in the unfinished part  18   a  shown by way of example, in the overlaid profile of  FIG. 6  to a recoiled position  32  when it is severed from the unfinished part  18   a  to form the finished part  18   b  along the cut line  46 . As noted above, the springback to a recoiled position  32  can be dangerous and problematic. 
     In order to control recoil associated with complex contours  28  in a part  18   a , complementary elongate bead forming regions  36  and  38  are provided in the deep drawing protrusion region  20  and the deep drawing receiving region  22  for stamping an elongate bead  42  through a complex contour  28  in the scrap region as shown in  FIGS. 1 to 4 . The bead forming regions are provided as an elongate male bead-forming protrusion  36  located on either the first die body  12  or the second die body  14  and a complementary elongate bead die escape  38  located on the other. In this case, the complex contour  28  on the part  18   a  is provided as a a relatively tight bend region. Exemplary embodiments of stamped parts  18   a  shown in  FIGS. 9 a  to 9 f    illustrate examples of complex contours  28  having elongated beads  42  formed therein and scrap regions  34 . In this case, the bead forming regions are positioned so that beads extend through the bend region and are of a size and orientation to deform the scrap region to inhibit the recoil, arising in part from the bend region. The width, length and depth of the so-formed bead is then selected according to the sweep or extent of the bend and its radius, the thickness of the metal blank and its tensile strength, among other characteristics. 
     Furthermore, as is shown schematically in  FIG. 4 , for example, the scrap region  34  may be severed from the final part  18   b  ( FIG. 5 b   ) using a punch mechanism  44  operably incorporated in the upper and lower dies  12 ,  14 . In various other embodiments, the punch mechanism  44  may be provided in a separate processing step. In additional exemplary embodiments, a separate processing step may be utilized to sever the scrap region  34  from the final part  18   b  along the cut line  40 , as shown in the figures. 
     As shown in the figures particularly in  FIGS. 2 and 3 , the elongate bead forming regions  36  and  38  follow the contour  28  within the scrap region  34  to form the elongate bead, which in turn provides a stiffening effect to the contour  28  once it is severed from the final part  18   b . The stiffening effect substantially maintains the scrap region  34  in a neutral stamped position  30  upon severance as is shown with reference to  FIG. 6 . 
     In certain embodiments, shown by way of example in  FIGS. 2, 4 and 7 , the elongate bead forming protrusion  36  may be shorter in length than die escape  38 . The shorter length of the bead forming protrusion  36  relative the die escape  38  is provided such that material flow is not affected during the stamping process, thus increasing the quality of the final part  18   b.    
       FIG. 8 , by way of example, shows a final sheet metal stamped part  18   b  in this case for a vehicle panel. Scrap regions are provided at  34   a  and  34   b  which are deep-drawn by the interaction of the sheet metal blank  16  with the deep drawing protrusion region  20  and the deep drawing receiving region  22  during the stamping process. The scrap regions, shown in  FIG. 8 , are provided as a wheel-well scrap region  34   b  and a tail-light scrap region  34   a , each with at least one elongate bead  42  for maintaining the scrap region  34  in a substantially neutral stamped position  30 . In practice, when the scrap region  34  is severed from the final part  18  along the cut line  40 , the scrap region  34  is substantially inhibited from recoil by the stiffing action of the elongated bead  42  about the complex contour  28  of the deep draw. 
     In practice, with particular reference to  FIG. 6 , the placement of at least one elongate bead  42  in a complex contour  28  or deep-drawn bend  28  may thus be provided to aid in shape-retention of the deep-drawn region.  FIG. 6  shows the profile of a stamped part  18   a  along line  6 - 6  of  FIG. 5 a   , wherein an elongate bead  42  is formed in the deep-drawn complex contour section  28  and a part cut line is represented as a dotted line at  40 . Also in  FIG. 6 , shown in ghost, is the profile of the recoiled part  32  which does not have a bead  42  formed in a deep-drawn complex contour region  28  of the scrap region  34 . Owing to the lack of a bead  42  in the ghosted recoiling part  32 , the scrap region  34  is prone to recoil when severed from the final stamped part  18   b . The neutral stamped position  30  of part  18   b  and the recoiling position  32  of the scrap region  34  are shown as overlays with the cut line  40  to denote the final part  18   b , for explanatory purposes of the elongate bead  42 . 
     Thus, in one example, the incorporation of at least one elongated bead  42  in the scrap region  34  by virtue of the stamping sheet metal stamping process and device  10 , the scrap region  34  remains substantially rigid or otherwise substantially retains its stamped shape or profile, as defined by a neutral stamped position  30 , once it is trimmed to from the final part  18   b . By encouraging the scrap region  34  to remain in the neutral stamped position  30  after being trimmed from the final part  18   b , the recoiling or springback properties of deep drawn sheet metal can be substantially controlled. Being able to better control the recoil properties of deep drawn scrap region  34  improves efficiency of certain aspects of the stamping manufacturing process. For example, by being able to maintain a more consistent shape of a severed scrap region  34  from one part to the next, recoil properties of the scrap region  34  can be better predicted and thus other components involved in a part-producing process, such as scrap kickers (not shown) and scrap trimmers (not shown) are less likely to be jammed or damaged by the scarp region  34  of various parts recoiling to unpredicted positions and causing jams or damage to the equipment of the part-producing process. Therefore, downtime related to clearing jams and maintaining equipment in the process is accordingly decreased by being able to substantially control the recoil characteristics of a severed scrap region  34 . 
     Thus, the device  10  provides a method for substantially retaining the shape of a stamped metal part  18   a , wherein a scrap region  34  is severed from the part  18   a  to form a final stamped part  18   b  as is shown in  FIG. 5 b   . As is shown in  FIG. 1  a sheet metal blank  16  is inserted between an upper die  12  and a lower die  14 . The upper and lower dies  12 ,  14  are caused to communicate, or engage, with the sheet metal blank as is shown in  FIG. 2  to produce and intermediate stamped part  18   a , as shown in  FIG. 3 . At least one elongate bead  42  is formed in a scrap region of the intermediate stamped part  18   a . The scrap region  34  is then removed along a predetermined cut line  40  ( FIGS. 2, 5   a , and  6 ) to produce a final part  18   b  as is shown in  FIG. 5 b   .  FIGS. 9 a  to 9 f    show various exemplary embodiments of stamped parts  18   a  prior the removal of the scrap region  34  along various respective cut lines  40 . The elongate beads  42  formed in a deep-drawn complex contour  28  of the scrap region  34 , thus substantially inhibit the scrap region  34  from undergoing recoil to a recoiled position  32  as in  FIG. 6  when the scrap region  34  is severed. 
     Those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof of parts noted herein. While the sheet metal stamping device for substantially inhibiting recoil from a neutral stamped position of a scrap part region  10  has been described for what are presently considered the exemplary embodiments, the invention is not so limited. To the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.