Patent Publication Number: US-2005127575-A1

Title: Method of forming a vehicle trim panel

Description:
BACKGROUND OF THE INVENTION  
      This invention relates to interior vehicle trim panels. More particularly, the invention relates to a method of manufacturing interior vehicle trim panels.  
      It is known to provide an interior trim panel for a vehicle which is aesthetically and/or tactilely pleasing to the vehicle occupants. Such interior trim panels typically comprise a relatively rigid structural substrate of thermoplastic or the like. The B-side surface of a cover-stock material such as leather, vinyl, or textile material is typically bonded to the A-side surface of the substrate. As used herein, the A-side surface refers to the surface of the substrate or the cover-stock which is exposed to the vehicle occupant. The B-side surface refers to the surface of the substrate or the cover-stock which is opposite the A-side surface and which faces away form the vehicle occupant. Commonly, cover-stock material is attached to the structural substrate by a variety of known methods, such as for example, by hand, by vacuum forming, and by low pressure molding.  
      However, known methods of manufacturing interior vehicle trim panels can add significant cost to each vehicle produced. It would therefore be desirable to provide an improved method of manufacturing an interior trim panel for a vehicle.  
     SUMMARY OF THE INVENTION  
      The present invention relates to a method of manufacturing a vehicle trim component including providing a thermoplastic substrate. A first material, which is different from the material of the thermoplastic substrate, is also provided. A portion of a surface of the thermoplastic substrate is exposed to a source of heat such that the portion of the surface of the thermoplastic substrate exposed to the source of heat is melted. The first material is then positioned onto the thermoplastic substrate so as to bring the first material into contact with the melted surface of the thermoplastic substrate, thereby bonding the first material to the thermoplastic substrate and forming a vehicle trim component.  
      Other advantages of this invention will become apparent to those skilled in the art from the following detailed description of the invention, when read in light of the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an exploded perspective view of a vehicle trim panel manufactured according to the method of this invention.  
       FIG. 2  is a schematic perspective view of a press used in accordance with the method of this invention, showing the press in the open position.  
       FIG. 3  is a cross sectional elevational view showing the press illustrated in  FIG. 1  in the closed position, showing vehicle trim panel therein.  
       FIG. 4  is a schematic perspective view of a press used in accordance with a second embodiment of the method of this invention, showing the press in the open position.  
       FIG. 5  is a schematic perspective view of a press used in accordance with a third embodiment of the method of this invention, showing the press in the open position.  
       FIG. 6  is a schematic perspective view of a press used in accordance with a fourth embodiment of the method of this invention, showing the press in the open position.  
       FIG. 7  is a cross sectional elevational view showing the press illustrated in  FIG. 6  in the closed position, showing vehicle trim panel therein. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring now to the drawings, there is illustrated in  FIG. 1 a  vehicle trim component or panel assembly, generally shown at  10 . The trim panel assembly  10  comprises a substrate or trim panel  12  having an A-side surface  14 . The trim panel  12  includes a first material or coverstock  16  attached thereto. The coverstock  16  defines an accent region  18  (illustrated by a phantom line) of the trim panel  12 .  
      The exemplary trim panel assembly  10  illustrated in  FIG. 1  is an automotive door trim panel which mounts to a vehicle door assembly, generally shown at  20 . It will be appreciated however, that the trim panel  12  of the subject invention may be any type of trim panel associated with a trim panel assembly for a vehicle. For example, other types of trim panels include trunk panels, quarter panels, rear package trays, headliners, instrument panels, garnish moldings, and console panels, among others.  
      The door trim panel  12  is preferably formed of a molded thermoplastic material such as polypropylene. As appreciated by those skilled in the art, the trim panel  12  may be fabricated of other materials, such as, polyurethane, solid molded vinyl, expanded polyurethane foam, any combination thereof, or any other desired thermoplastic material. The A-side surface  14  of the trim panel  12  may include a decorative surface portion, such as the accent region  18 . The coverstock  16  is formed of any desired material, such as for example, vinyl, cloth, carpet, leather, or any other desired material. The trim panel  12  may be attached to the vehicle door assembly  20  by any suitable fasteners (not shown) as are well known in the art.  
      A first embodiment of the method of the invention is illustrated in  FIGS. 2 and 3 . Referring to  FIG. 2 , there is illustrated a press, indicated generally at  22 , which is adapted to be used in accordance with the method of this invention. Typically, the press  22  includes a first press half  24 , a second press half  26 , and a source of heat  28 . The first press half  24  includes a first nest  30 , and the second press half  26  includes a second nest  32 . Although illustrated schematically in  FIGS. 2 through 7 , it will be appreciated that the press halves  24  and  26 , and the nests  30  and  32  may be of any desired shape and contour. It will be appreciated that as used herein, the term nest is defined as having any desired shape, including any of a substantially convex, substantially concave, or a combination convex and concave shape.  
      The first press half  24  and second press half  26  are preferably mounted to platens (not shown) of a press assembly (not shown) with sufficient tonnage to accomplish the method herein described. The press  22  can be moved between an open position, as shown in  FIG. 2  and a closed position, as shown in  FIG. 3 . The source of heat  28  has a heat generating surface  34  and is disposed between the first press half  24  and the second press half  26 .  
      It will be appreciated, that in accordance with each embodiment of the invention, as will be described below, a first step of the method of the invention includes providing a suitable press, such as the press  22 .  
      A second step of the method of this invention is illustrated generally in  FIG. 2 . In the second step, the press  22  is moved to the open position. It will be appreciated that the open position can be achieved by moving the first press half  24  away relative to the second press half  26 , moving the second press half  26  away relative to the first press half  24 , or moving each of the first press half  24  and the second press half  26  away from the other.  
      A substrate, such as the trim panel  12  is then disposed in the first nest  30 . A first material, such as the coverstock  16  is disposed in the second nest  32 . The coverstock  16  can be held against the surface of the second nest  32  by any desired means, such as for example, by vacuum or by needle pad retention. It will be appreciated that if desired, the coverstock  16  can be disposed in the first nest  30 , and the trim panel  12  can be disposed in the second nest  32 . In the exemplary embodiment illustrated, the coverstock  16  is shown smaller than the trim panel  12  to which it is attached (i.e. equal in size to the accent region  18 ). It will be appreciated however, that the coverstock  16  can be any desired size. For example, the coverstock  16  can be equal in size to the A-side surface  14  of the trim panel  12  to which it is attached. The source of heat  28  is then positioned between the first press half  24  and the second press half  26 , such that the heat generating surface  34  is facing the trim panel  12 .  
      The source of heat  28  is preferably a source of radiant heat. The source of heat  28  can be any suitable source of radiant heat sufficient to melt the surface of a thermoplastic substrate as described herein. The source of radiant heat can be provided by any desired means. For example, the radiant heat can provided by a flash of high intensity heat from a light source, such as shown generally at  36  in  FIG. 5 , by infrared light, by a laser, or by any other desired source of radiant heat. Additionally, other sources of heat can be used, such as for example, natural gas or LP fired heat, quartz, contact, and hot air heat systems. Preferably, the source of heat  28  is fixed relative to the surface of the trim panel  12 , such that the portion of the A-side surface of the trim panel  12  to be melted, such as the accent region  18 , is exposed to heat from the source of heat  28  substantially simultaneously. As used herein, a flash is defined as a short burst of heat having a duration within the range of from about 0.2 seconds to about 0.8 seconds. High intensity is defined as having a temperature sufficient to melt the substrate  12 . For example, for a substrate made of polypropylene, high intensity heat is defined as within the range of from about 400 degrees F. to about 480 degrees F.  
      A portion of the surface of the trim panel  12 , such as the accent area  18 , is then exposed to heat from the source of heat  28  such that the surface of the trim panel  12  within the accent area  18  is melted. It will be appreciated that any desired combination of the duration and intensity of the heat can be used such that within the range of from about 0.001 inches to about 0.010 inches of the A-side surface of the trim panel  12  is melted. It will be further appreciated the as used herein, the term melted is defined as softened such that the B-side surface of the coverstock  16  becomes embedded in the softened A-side surface of the trim panel  12 . Further, when cooled, the coverstock then becomes mechanically bonded or fused to the trim panel  12 .  
      In a third step of the method, the source of heat  28  is moved from between the press halves  24  and  26 . In a fourth step of the method, the press halves  24  and  26  are moved to the closed position, as shown in  FIG. 3 . In the closed position, the coverstock  16  is positioned onto the trim panel  12  so as to bring the coverstock  16  into contact with the melted surface of the trim panel  12 . The coverstock  16  thereby becomes bonded to the trim panel  12  to form the vehicle trim panel assembly  10 . It will be appreciated that the closed position can be achieved by moving the first press half  24  toward the second press half  26 , moving the second press half  26  toward the first press half  24 , or moving each of the first press half  24  and the second press half  26  toward the other.  
      Referring now to  FIG. 4 , and using like reference numbers to indicate corresponding parts, there is illustrated a second embodiment of the method according to the present invention.  
      In the second embodiment, a press, indicated generally at  22 ′, is provided. The press  22 ′ includes the first press half  24 , the second press half  26 , and a source of heat  40 . The source of heat  40  has a heat generating surface  42  and is disposed between the first press half  24  and the second press half  26 . The source of heat  40  is preferably a source of radiant heat. The source of heat  40  can be any suitable source of radiant heat sufficient to melt the surface of trim panel  12  as described herein. The source of radiant heat can be provided by any desired means. For example, the radiant heat can provided by a flash of high intensity heat from a light source, by infrared light, by a laser, or by any other desired source of radiant heat. Additionally, other sources of heat can be used, such as for example, natural gas or LP fired heat, quartz, contact, and hot air heat systems. The source of heat  40  is preferably movable relative to the surface of the trim panel  12 .  
      According to the second embodiment of the method of the invention, the press  22 ′ is moved to the open position. The trim panel  12  is then disposed in the first nest  30 , and the coverstock  16  is disposed in the second nest  32 . The source of heat  40  is positioned between the first press half  24  and the second press half  26 , such that the heat generating surface  42  is facing the trim panel  12 . A source of power (not shown) then causes the source of heat  40  to move from a first side  43  of the trim panel  12  to a second side  45  of the trim panel  12 , as shown by an arrow  44 . The portion of the A-side surface of the trim panel  12  to be melted, such as the accent region  18 , is thereby exposed to heat from the source of heat  40 , as the source of heat  40  moves in the direction of the arrow  44 .  
      The press halves  24  and  26  are then moved to the closed position, as shown in  FIG. 3 . In the closed position, the coverstock  16  is positioned onto the trim panel  12  so as to bring the coverstock  16  into contact with the melted surface of the trim panel  12 . The coverstock  16  thereby becomes bonded to the trim panel  12  to form the vehicle trim panel assembly  10 .  
      In the second embodiment of the method, the heat source y has been described as moving relative to the trim panel  12  and the first nest  30 . It will be appreciated however, that in the first nest  30  may be moved relative to the source of heat  40 , or that both the source of heat  40  and the first nest  30  may be moved relative to each other.  
      Referring now to  FIG. 5 , and using like reference numbers to indicate corresponding parts, there is illustrated a third embodiment of the method according to the present invention. In the third embodiment, a press, indicated generally at  22 ″, is provided. The press  22 ″ includes a first press half  46  having a first nest  48 , a second press half  50  having a second nest  52 , and the source of heat  54 .  
      The source of heat  54  has a heat generating element of surface  56  and is disposed adjacent the second nest  52  of the second press half  50 . Preferably, the source of heat  54  is mounted to the second press half  50 , as shown in  FIG. 5 .  
      The source of heat  54  is preferably a source of radiant heat. The source of heat  54  can be any suitable source of radiant heat sufficient to melt the surface of trim panel  12  as described herein. The source of radiant heat can be provided by any desired means. For example, the radiant heat can provided by a flash of high intensity heat from a light source, by infrared light, by a laser, or by any other desired source of radiant heat. Additionally, other sources of heat can be used, such as for example, natural gas or LP fired heat, quartz, contact, and hot air heat systems.  
      According to the third embodiment of the method of the invention, the press  22 ″ is moved to the open position. The trim panel  12  is then disposed in the first nest  48 , and the coverstock  16  is disposed in the second nest  52 . The source of heat  54  is positioned such that the heat generating surface  56  is facing the trim panel  12 . Preferably, the second press half  50  is movable relative to the surface of the trim panel  12 . A source of power (not shown) causes the second press half  50 , and the source of heat  54  mounted thereto, to move from a first side  55  of the trim panel  12  to a second side  57  of the trim panel  12 , as shown by an arrow  58 . The portion of the A-side surface of the trim panel  12  to be melted, such as the accent region  18 , is thereby exposed to heat from the source of heat  54 , as the second press half  50  and the source of heat  54  move in the direction of the arrow  58 .  
      The press halves  46  and  50  are then moved to the closed position (not shown). In the closed position, the coverstock  16  is positioned onto the trim panel  12  so as to bring the coverstock  16  into contact with the melted surface of the trim panel  12 , as shown in  FIG. 3 . The coverstock  16  thereby becomes bonded to the trim panel  12  to form the vehicle trim panel assembly  10 .  
      In the third embodiment of the method, the source of heat  54  has been described as being moving relative to the trim panel  12  and the first press half  46 . It will be appreciated however, that in the first press half  46  may be moved relative to the second press half  50 , or that both the first press half  46  and second press half  50  may be moved relative to each other. It will be further appreciated that the source of heat  54  need not be mounted to the second press half  50 , as shown in  FIG. 5 . For example, if desired, the source of heat  54  can be disposed adjacent the second press half  50  such that the source of heat  54  and the second press half  50  move simultaneously.  
      In each of the first, second, and third embodiments of the method of the invention, thermoplastic material of the A-side surface  14  of the trim panel  12  is heated by a source of heat  28 ,  40 , or  54 . It will be appreciated however, that a coverstock  60  can include a B-side layer, as shown at  62  in  FIG. 7 , and a coverstock layer  64 . The B-side layer  62  is formed of any desired thermoplastic, such as polypropylene. As appreciated by those skilled in the art, the B-side layer  62  may be fabricated of other materials, such as, polyurethane, solid molded vinyl, or any other desired thermoplastic material. The coverstock layer  64  is formed of any desired material, such as, for example, from vinyl, cloth, carpet, leather, and the like.  
      When such a coverstock  60  is provided, the heat source, such as a source of heat  65  shown in  FIG. 6 , is disposed between the first press half  24  and the second press half  26  such that a heat generating surface  66  is facing the B-side layer  62  of the coverstock  60 . The B-side layer  62  of the coverstock  60  is then exposed to heat from the source of heat  66  and caused to melt, as described herein.  
      As previously disclosed, the press halves  24  and  26  are then moved to the closed position, as shown in  FIG. 7 . In the closed position, the coverstock  16  is positioned onto the trim panel  12  so as to bring the melted B-side surface  66  of the coverstock  60  into contact with the trim panel  12 . The coverstock  60  thereby becomes bonded to the trim panel  12  to form the vehicle trim panel assembly  10 .  
      One advantage of the method of the invention is that no adhesive is required between the trim panel  12  and the coverstock  16  and  60 , thereby reducing cost and eliminating the time required for the adhesive to cure. Volatile Organic Compounds (VOC) which can be associated with adhesives are also eliminated. Because no adhesive is used, humidity in the manufacturing facility need not be controlled.  
      In the exemplary embodiment of the method wherein the coverstock includes a B-side layer of thermoplastic, such as polypropylene, the coverstock has increased rigidity. Such increased rigidity provides a coverstock that can more easily retain its shape prior to being placed in the press nest. The thermoplastic layer further provides an air-impermeable layer, allowing the use of a vacuum to retain the coverstock in the press nest, regardless of the nest orientation.  
      An advantage of using a flash of high intensity heat to melt the surface of either the trim panel or the thermoplastic layer of the coverstock is that the process is very fast. Such a fast process provides for an increase in the number of parts minute produced.  
      Another advantage of the method of the invention is that bond produced by the melting or fusing of the coverstock to the trim panel is more robust than an adhesive bond.  
      The principle and mode of operation of this invention have been described in its preferred embodiments. However, it should be noted that this invention may be practiced otherwise than as specifically illustrated and described without departing from its scope.