Abstract:
A vacuum molding method for manufacturing a molded article that has a substrate material and a covering material may includes positioning the substrate material and the covering material between a first molding surface of a first die and a second molding surface of a second die, and closing the first and second dies. The die closing step comprises engaging at least a portion of the periphery of the second die with the first die with interleaving the covering material and the substrate material therebetween.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to vacuum molding methods and apparatus for manufacturing a molded article, e.g., a laminated article that includes a substrate material and a covering material.  
         [0002]     A known vacuum molding apparatus (hereinafter simply referred to as a “molding apparatus”) for manufacturing a laminated article is taught by, for example, Japanese Laid-open Patent Publication Number 2005-125735. In this known art, as shown in  FIG. 4 , the molding apparatus  100  includes a first (lower) die assembly having a first (lower) vacuum molding die  101 , and a second (upper) die assembly having a second (upper) vacuum molding die  102  that is formed from a porous material. The first and second die assemblies are arranged and constructed to move toward and away from each other, so that the first and second dies  101  and  102  can be closed and opened. The first die  101  has a convex molding surface  101   s , and an annular die closing surface  101   f  that encircles the molding surface  101   s . In addition, the first die  101  is connected to a vacuum source  103 . Conversely, the second die  102  has a concave molding surface  102   s  substantially corresponding to the convex molding surface  101   s , and an annular die closing surface  102   f  that can contact the annular die closing surface  101   f  when the first and second dies  101  and  102  are closed. In addition, the second die  102  is connected to a vacuum source  105 .  
         [0003]     In order to manufacture the laminated article, under a condition that the first and second dies  101  and  102  are opened, a substrate material  104  is disposed on the molding surface  101   s  of the first die  101 . The substrate material  104  is previously shaped so as to have a shape corresponding to the shape of the molding surface  101   s . Also, the substrate material  104  is previously perforated so as to have air flow paths (not shown) in the thickness direction thereof. Conversely, a covering material  106  is disposed between the first and second dies  101  and  102  so as to be positioned adjacent to the substrate material  104  that is disposed on the molding surface  101   s . The covering material  106  is previously softened by heating and is previously applied with an adhesive. Thereafter, the first and second die assemblies are operated, thereby closing the first and second dies  101  and  102 . Upon closing of the first and second dies  101  and  102 , the covering material  106  is applied to the substrate material  104  while it is shaped by the molding surface  102   s  of the second die  102 . Simultaneously, the periphery of the covering material  106  is clamped between the die closing surfaces  101   f  and  102   f  of the first and second dies  101  and  102  along the substrate material  104 . As a result, the first and second dies  101  and  102  are sealed along the substrate material  104 , so that a hermetic molding cavity is defined therebetween.  
         [0004]     Subsequently, the vacuum source  105  of the second die  102  is actuated. As a result, the covering material  106  is drawn toward the molding surface  102   s  so as to be vacuum molded by the molding surface  102   s . Thereafter, the vacuum source  103  of the first die  101  is actuated. As a result, the molded covering material  106  is drawn toward the substrate material  104  disposed on the molding surface  101   s  via the perforated air flow paths formed in the substrate material  104 , so as to be adhered to the substrate material  104 . Thus, the laminate article is manufactured.  
         [0005]     According to the known molding apparatus, when the first and second dies  101  and  102  is closed, the periphery of the covering material  106  is clamped between the die closing surfaces  101   f  and  102   f  of the first and second dies  101  and  102 , thereby hermetically sealing the molding cavity positioned between the first and second dies  101  and  102 . Therefore, in the known apparatus, in order to seal the molding cavity, the substrate material  104  must be entirely covered with the covering material  106 , even if the substrate material  104  should be partly covered with the covering material  106 . In such case, in order to manufacture the laminate article in which the substrate material  104  is partly covered with the covering material  106 , it is necessary to manufacture the laminated article in which the substrate material  104  is entirely covered with the covering material  106  and then to partly uncover or remove the covering material  106  from the substrate material  104 . Therefore, time consuming and labor intensive work is required to manufacture the laminated article. In addition, manufacturing costs of the laminated article are increased.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     It is, accordingly, one object of the present invention to provide improved vacuum molding methods and apparatus for manufacturing a molded article.  
         [0007]     In one aspect of the present invention, a vacuum molding method is taught for manufacturing a molded article that has a substrate material and skin material. The method may includes positioning the substrate material and the covering material between a first molding surface of a first die and a second molding surface of a second die, closing the first and second dies, applying a negative pressure to the second molding surface of the second die so that the covering material is drawn toward the second molding die, thereby molding the covering material by the second molding surface, and applying a negative pressure to the first molding surface of the first die so that the covering material is drawn toward the first molding die, thereby adhering the covering material to the substrate material on the first die. The die closing step comprises engaging at least a portion of the periphery of the second die with the first die with interleaving the covering material and the substrate material therebetween.  
         [0008]     In another aspect of the present invention, a vacuum molding apparatus is taught for manufacturing a molded article that has a substrate material and a covering material. The apparatus may include a first die having a first molding surface that is arranged and constructed to receive the substrate material, a first vacuum source arranged and constructed to apply a negative force to the first molding surface, a second die having a second molding surface that is arranged and constructed to shape the covering material, and a second vacuum source arranged and constructed to apply a negative force to the second molding surface. At least a portion of the periphery of the second die is arranged and constructed to engage the first die with interleaving the covering material and the substrate material therebetween.  
         [0009]     According to the present method and apparatus, in order to form a hermetic molding cavity between the first and second molding surfaces of the first and second dies when the first and second dies are closed, the at least a portion of the second die can urge the first die while the covering material and the substrate material are clamped therebetween. Therefore, a portion of the substrate material that is not intended to be applied with the covering material can be positioned outside the molding cavity. As a result, the covering material can be adhered to only a necessary portion of the substrate material. Therefore, it is possible to manufacture the molded article in which only a necessary portion of the substrate material is covered with the covering material. That is, it is not necessary to partly remove the covering material from the substrate material. As a result, the usage of the covering material can be reduced. This may lead to a reduced manufacturing cost.  
         [0010]     Other objects, features and advantage of the present invention will be ready understood after reading the following detailed description together with the accompanying drawings and the claims. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0011]      FIG. 1 (A) is a sectional view of a vacuum molding apparatus for manufacturing a molded article according to a representative embodiment of the present invention, illustrating a condition in which upper and lower dies are closed;  
         [0012]      FIG. 1 (B) is an enlarged view of an encircled portion B of  FIG. 1 (A);  
         [0013]      FIG. 2  is a sectional view of the vacuum molding apparatus, illustrating a condition in which the upper and lower dies are opened;  
         [0014]      FIG. 3 (A) is a plan view of the lower die in  FIG. 2 ;  
         [0015]      FIG. 3 (B) is a cross-sectional view taken along line III(B)-III(B) in  FIG. 1 (A); and  
         [0016]      FIG. 4  is a sectional view of a conventional vacuum molding apparatus, illustrating a condition in which upper and lower dies are opened. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]     A preferred representative embodiment of the present invention is shown in FIGS.  1 (A) to  3 (B) in order to produce a molded article, in which a laminated instrument panel is exemplified as the molded article that can be prepared utilizing the present invention. The laminated instrument panel has a substrate material  14  and a covering material  25 . Further, in the drawings, the directions shown by references X, Y and Z respectively correspond to “a lateral direction,” “a longitudinal direction” and “a vertical direction.” 
         [0018]     As best shown in  FIGS. 1 and 2 , a vacuum molding apparatus  10  for manufacturing the laminated instrument panel may include a first (lower) die assembly  10   a  having a first (lower) vacuum molding die  11  that is formed from a porous material (i.e., air permeable material), and a second (upper) die assembly  10   b  having a second (upper) vacuum molding die  12  that is formed from a porous material (i.e., air permeable material). The first and second die assemblies  10   a  and  10   b  are arranged and constructed to vertically move toward and away from each other, so that the first and second dies  11  and  12  can be closed and opened.  
         [0019]     As shown in  FIGS. 2 and 3 (A), the first die  11  has a convex first molding surface  11   s  that can support the substrate material  14  thereon, and an annular die closing surface  11   f  that extends along the periphery of the first die  11 . The die closing surface  11   f  may preferably encircle the first molding surface  11   s . Further, the first die  11  is provided with an elongated cylindrical string-like sealing member  20  that extends in the longitudinal direction (the direction Y) along the first molding surface  11   s . The sealing member  20  is formed from an elastic material. As best shown in  FIG. 1 (B), the sealing member  20  may preferably be received in an elongated groove  11   m  formed in the first die  11 , so as to be positioned in place on the first die  11 . In addition, the first die  11  is connected to a first vacuum source S 1  in order to apply negative pressure to the first molding surface  11   s.    
         [0020]     Conversely, as shown in  FIG. 2 , the second die  12  has a concave second molding surface  12   s , and a die closing surface  12   f  that extends along one portion of the periphery of the second die  12 . The concave second molding surface  12   s  substantially corresponds to the convex first molding surface  11   s  of the first die  11 . The die closing surface  12   f  may partly surround the second molding surface  12   s . The die closing surface  12   f  is arranged and constructed to partly surround the periphery of the first molding surface  11   s  when the first and second dies  11  and  12  are closed. Also, the die closing surface  12   f  is arranged and constructed to face a substantial portion of the annular die closing surface  11   f  when the first and second dies  11  and  12  are closed. Further, the second die  12  has a pressure applying edge  12   p  that extends along the other portion of the periphery of the second die  12 . The pressure applying edge  12   p  may partly surround the second molding surface  12   s  and having a width of about 10 mm. The pressure applying edge  12   p  may preferably be continuous to the die closing surface  12   f , so that the second molding surface  12   s  is encircled by the die closing surface  12   f  and the pressure applying edge  12   p . The pressure applying edge  12   p  is formed so as to correspond to the sealing member  20  disposed on the first die  11  when the first and second dies  11  and  12  are closed. In addition, similar to the first die  11 , the second die  12  is connected to a second vacuum source S 2  in order to apply negative pressure to the second molding surface  12   s.    
         [0021]     As shown in  FIG. 2 , the vacuum molding apparatus  10  may further include a clamping device  27 . The clamping device  27  is arranged and constructed to clamp the periphery of the covering material  25  that is formed as a sheet-shaped member. The clamping device  27  can be moved such that the covering material  25  can be horizontally supported between the first and second dies  11  and  12  when the first and second dies  11  and  12  are opened.  
         [0022]     As shown in  FIG. 2 , the vacuum molding apparatus  10  may further include a heating device  30 . The heating device  30  is arranged and constructed such that the covering material  25  supported by the clamping device  27  can be heated at both surfaces so as to be softened. The heating device  30  can be horizontally moved between a heating position shown in  FIG. 2  and a retracted position (not shown). As will be appreciated, in the retracted position, the heating device  30  does not interfere with the first and second dies  11  and  12  even if the first and second dies  11  and  12  are moved from a opening position shown in  FIG. 2  to a closing position shown in  FIG. 1 .  
         [0023]     Further, the substrate material  14  is previously shaped so as to correspond to the shape of the first molding surface  11   s . The substrate material  14  may preferably be formed by injection molding a synthetic resin, e.g., polypropylene (PP). Also, the substrate material  14  is previously perforated so as to have a plurality of air flow paths (not shown) extending in the thickness direction thereof. As best shown in  FIG. 3 , the substrate material  14  may include a covered portion  14   c  (an area shown by cross-hatching) that should be covered by the covering material  25 , and a exposed or exposed portion  14   z  that should be left uncovered. The covered portion  14   c  may have an elongated pressed portion  14   r  that can be pressed by the pressure applying edge  12   p  of the second die  12 . The pressed portion  14   r  is positioned adjacent to the exposed portion  14   z  and having a width of about 10 mm. As will be recognized, the pressed portion  14   r  is also positioned so as to correspond to the sealing member  20  disposed on the first die  11 . As a result, as shown in  FIG. 1 (B), when the first and second dies  11  and  12  are closed, the pressed portion  14   r  may preferably be substantially aligned with the pressure applying edge  12   p  of the second die  12  and the sealing member  20  along a line L.  
         [0024]     Conversely, the covering material  25  may preferably be formed as a laminate sheet having an upper or skin layer and a lower or foamed layer (not shown) that are adjoined with each other. The skin layer may preferably be formed as a thin film of a thermoplastic resin, e.g., a thermoplastic olefin (TPO). Conversely, the foamed layer may preferably be formed as a thin foamed film of a foamed resin, e.g., a foamed polypropylene (PP). The laminate sheet may further have an adhesive that is applied to the foamed layer (the foamed film). An example of the adhesive may be a hot-melt olefin adhesive.  
         [0025]     A representative method for manufacturing the laminated instrument panel using the vacuum molding apparatus  10  will now be described. First, as shown in  FIG. 2 , under a condition that the first and second dies  11  and  12  are opened, the pre-shaped substrate material  14  is disposed on the first molding surface  11   s  of the first die  11 .  
         [0026]     Thereafter, the covering material  25  having a desired shape and size is attached to the clamping device  27 . The clamping device  27  is then moved, so that the covering material  25  is horizontally positioned between the opened first and second dies  11  and  12  while the foamed layer of the covering material  25  faces the substrate material  14  disposed on the first die  11 .  
         [0027]     Subsequently, the heating device  30  is horizontally moved from the retracted position to the heating position, so that the covering material  25  supported by the clamping device  27  is heated at both surfaces. When the covering material  25  is softened by heating, the heating device  30  is returned to the retracted position.  
         [0028]     Next, the first die assembly  10   a  is operated, so that the first die  11  is moved upwardly to a predetermined elevated position until the covering material  25  supported by the clamping device  27  is overlaid the substrate material  14  disposed on the first die  11 . Thereafter, the second die assembly  10   b  is operated, so that the second die  12  is moved downwardly until the first and second dies  11  and  12  are closed ( FIG. 1 (A)).  
         [0029]     Upon closing of the first and second dies  11  and  12 , as shown in  FIG. 1 (A), the covering material  25  is applied to the substrate material  14  (the covered portion  14   c ) disposed on the first die  11  while it is shaped by the second molding surface  12   s  of the second die  12 . At this time, the die closing surface  12   f  of the second die  12  urges or engages the die closing surface  11   f  of the first die  11  with interleaving the covering material  25  therebetween. That is, the covering material  25  is securely clamped between the die closing surfaces  11   f  and  12   f  of the first and second dies  11  and  12  along the periphery of the covered portion  14   c  of the substrate material  14 . As a result, the closed first and second dies  11  and  12  are reliably sealed along a substantial portion of the periphery of the covered portion  14   c  of the substrate material  14 .  
         [0030]     Conversely, at this time, the pressure applying edge  12   p  of the second die  12  urges or engages the first die  11  (the sealing member  20  disposed on the first die  11 ) with interleaving both of the covering material  25  and the pressed portion  14   r  of the substrate material  14  therebetween ( FIG. 1 (B)). That is, the covering material  25  is securely clamped between the pressure applying edge  12   p  of the second die  12  and the pressed portion  14   r  of the substrate material  14  while the pressed portion  14   r  of the substrate material  14  is pressed to the first die  11  via the sealing member  20 . As a result, the closed first and second dies  11  and  12  are reliably sealed along a remaining portion of the periphery of the covered portion  14   c  of the substrate material  14 .  
         [0031]     Thus, the closed first and second dies  11  and  12  are annularly sealed along the periphery of the covered portion  14   c  of the substrate material  14 , so that a hermetic molding cavity is defined between the molding surfaces  11   s  and  12   s  of the closed first and second dies  11  and  12 . As will be appreciated, the formed hermetic molding cavity may contain the covered portion  14   c  of the substrate material  14  and the covering material  25  applied thereon. In other words, the exposed portion  14   z  of the substrate material  14  that is not intended to be applied with the covering material  25  is positioned outside the molding cavity.  
         [0032]     Subsequently, the second vacuum source S 2  of the second die  12  is actuated, so that the negative pressure is applied to the second molding surface  12   s . As a result, the covering material  25  is drawn toward the second molding surface  12   s  so as to be molded by the second molding surface  12   s . The drawn covering material  25  (the skin layer of the covering material  25 ) may preferably be embossed with a decorative pattern corresponding to a pattern (not shown) of the second molding surface  12   s . Upon completion of the embossing operation, the second vacuum source S 2  of the second die  12  is deactuated. After the second vacuum source S 2  of the second die  12  is deactuated, the first vacuum source S 1  of the first die  11  is actuated, so that the negative pressure is applied to the first molding surface  11   s . As a result, the covering material  25  is drawn toward the covered portion  14   c  of the substrate material  14  because the substrate material  14  is formed with the air flow paths extending in the thickness direction thereof. The drawn covering material  25  (the foamed layer of the covering material  25 ) may preferably be adhered to the covered portion  14   c  of the substrate material  14  via the adhesive (the hot-melt adhesive) applied to the foamed layer of the covering material  25 . Thus, the laminated instrument panel is vacuum molded within the hermetic molding cavity of the first and second dies  11  and  12 . Thereafter, the first and second dies  11  and  12  are opened in order to remove the formed laminated instrument panel therefrom. The removed laminated instrument panel may preferably be finished by trimming or other such processing.  
         [0033]     According to the present method, when the first and second dies  11  and  12  are closed, the covering material  25  and the pressed portion  14   r  of the substrate material  14  can be clamped between the pressure applying edge  12   p  of the second die  12  and the sealing member  20  disposed on the first die  11 , so that the closed first and second dies  11  and  12  can be sealed along a portion of the periphery of the covered portion  14   c  of the substrate material  14 . Therefore, the exposed portion  14   z  of the substrate material  14  that is not intended to be applied with the covering material  25  can be positioned outside the molding cavity. As a result, the covering material  25  can be adhered to only the covered portion  14   c  of the substrate material  14 . That is, the exposed portion  14   z  can be left uncovered during the vacuum molding. Therefore, it is possible to manufacture the laminated instrument panel in which only a necessary portion of the substrate material  14  is covered with the covering material  25 . As a result, the usage of the covering material  25  can be reduced. This may lead to a reduced manufacturing cost.  
         [0034]     The sealing member  20  may effectively increase sealing performance between the first and second dies  11  and  12 . Also, the sealing member  20  may reduce rattling produced between the first and second dies  11  and  12 . In addition, the present method may contribute to downsizing of the vacuum molding apparatus  10 .  
         [0035]     Although the second die  12  has the die closing surface  12   f  and the pressure applying edge  12   p  in the representative embodiment, the second die  12  may have only the pressure applying edge  12   p , if necessary. That is, the pressure applying edge  12   p  may extend along the entire portion of the periphery of the second die  12 , so as to encircle the second molding surface  12   s . In such a case, the sealing member  20  may preferably be configured so as to correspond to the pressure applying edge  12   p  when the first and second dies  11  and  12  are closed. For example, the sealing member  20  may be formed so as to have a frame or ring shape. According to the modified embodiment, it is possible to manufacture a laminated instrument panel in which only the central portion of the substrate material  14  is covered with the covering material  25  (i.e., in which the peripheral portion of the substrate material  14  is not covered with the covering material  25 ).  
         [0036]     The adhesive is applied to the covering material  25  in the representative embodiment. However, the adhesive can instead be applied to the substrate material  14 .  
         [0037]     The string-like sealing member  20  has a cylindrical shape in cross section in the representative embodiment. However, the sealing member  20  may have various cross-sectional shapes, e.g., an oval shape and a polygonal shape.  
         [0038]     Further, in the representative embodiment, the first vacuum source S 1  of the first die  11  is actuated after the second vacuum source S 2  of the second die  12  is deactuated. However, the first vacuum source S 1  of the first die  11  can be actuated while the second vacuum source S 2  of the second die  12  is still being actuated.  
         [0039]     A representative example of the present invention has been described in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present invention and is not intended to limit the scope of the invention. Only the claims define the scope of the claimed invention. Therefore, combinations of features and steps disclosed in the foregoing detail description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe detailed representative examples of the invention. Moreover, the various features taught in this specification may be combined in ways that are not specifically enumerated in order to obtain additional useful embodiments of the present invention.