Abstract:
An apparatus and method for making a trim panel. The method includes providing a preform laminate including a compressible material sandwiched between a flexible skin and a back skin. Positioning the preform laminate in the mold. Placing an insert with the preform laminate in the mold to created a step to establish a seam location and define a secondary area on the preform laminate. Compressing the compressible material by introducing a molten polymeric material to the mold forming a substrate and bonding the substrate to the preform laminate forming the trim component. The preform laminate folds onto itself and creates a crease along the step to simulate the seam and provide a contour change with the appearance of cushioning in the secondary area, and removing the trim panel component from the mold.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This Application is a National Stage of PCT/US2008/050091, filed Jan. 3, 2008, which claims the benefit and PCT International Application claiming priority and the benefit of to U.S. Provisional Application Ser. No. 60/878,933, filed Jan. 5, 2007 and U.S. Provisional Application Ser. No. 60/936,261, filed Jun. 19, 2007. The foregoing applications are incorporated by reference herein in their entirety. 
    
    
     BACKGROUND 
     The present application relates to the field of molded articles having soft portions with stitching, embroidery and/or other sewn portions (which will collectively be referred to as “stitching”). More specifically, the present application further relates to interior trim panels or structures for vehicles (e.g., automobiles such as cars, trucks, and the like; airplanes, boats, etc.) or other products that include at least one relatively localized deep soft area (e.g., padded or cushioned) portion formed by a partial-mold-behind (PMB) process that may also have stitching (decorative or functional) and be configured to separate from the main body of the product. 
     Padded or cushioned vehicle interior components may include stitching. Such stitching may be decorative/ornamental and/or functional. The padded or cushioned vehicle interior components may take the form of a trim panel (e.g., instrument panel, door panel, etc.). Such panels typically include a substrate made of a relatively rigid material, a relatively soft core (e.g., a foam layer), and an outer surface or skin. Various methods of providing such cushioning and stitching are known in the art, although such known methods do not provide certain advantageous features and/or combination of features. For example, it is known to add stitching to interior components to the skin (or skin and foam laminate) and then attach the skin to the substrate by a hand or manually wrapping technique. It is also known to apply the stitching after the interior component has been formed (e.g., after the skin, foam, and substrate has been joined). Such padded or cushioned components may also be used in conjunction with devices, such as airbags, located in a dashboard or door panel or the like. However, known methods of applying decorative stitching are labor-intensive or do not provide the desired visual effect of depth that would be provided by a recessed stitch (e.g., “quilting” or cushioning effect that provides contour change in the soft surface). Therefore, such recessed stitching provided by known costly manufacturing processes are typically only available on premium or luxury class vehicles. 
     The present application further relates to various features and combinations of features shown and described in the disclosed embodiments. 
     SUMMARY 
     There is provided a method of forming a trim component in a mold. The method comprises providing a preform laminate comprising a compressible material sandwiched between a flexible skin and a back skin. The preform laminate defines a step at a pre-determined position. Positioning the preform laminate in the mold. Placing an insert with the preform laminate in the mold. Compressing the compressible material by introducing a molten polymeric material to the mold forming a substrate and bonding the substrate to the preform laminate forming the trim component. Wherein the preform laminate folds onto itself and creates a crease along the step to simulate a seam and provide a contour change with the appearance of cushioning in the secondary area, and removing the trim component from the mold. 
     There is also provided a trim component for a vehicle which comprises a preform laminate piece comprising a compressible material sandwiched between a flexible skin and a back skin. An insert coupled to the preform laminate, wherein the insert abuts a step on the preform laminate wherein the step separates a primary area and a secondary area. A substrate coupled to the preform laminate, wherein a crease along the step simulates a seam and creates a contour change between the secondary area and the primary area. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a vehicle with an airbag system and a seamless partial mold behind (PMB) interior panel. 
         FIG. 2  is an illustration of a vehicle door panel including a faux deck seam. 
         FIG. 3  is an illustration of a prior art a door panel. 
         FIG. 4  is an illustration of a seamless door panel fabricated using PMB and including a hard portion and a soft portion with the soft portion including an insert with a simulated stitch. 
         FIG. 5  is an illustration of a preformed piece for a door panel that includes one of a TPO and polyvinylchloride top skin, a polyolefin foam center layer and a thermoplastic polyolefin (TPO) back skin. 
         FIG. 6  is an illustration of a preformed piece for a door panel that includes a step formed by an insert placed into a negative forming tool. 
         FIG. 7  is a cross-sectional view of a portion of a preformed piece of a panel including one of a thermoplastic polyolefin (TPO) and polyvinylchloride top skin, a polyolefin foam center layer and a TPO back skin. 
         FIG. 8  is the cross-sectional view of the preformed piece illustrated in  FIG. 7  with a secondary cloth material (insert) installed in a secondary area. 
         FIG. 9 . is a cross-sectional of the preformed piece illustrated in  FIG. 7  with a secondary leather material (insert) installed in the secondary area. 
         FIG. 10  is a cross-sectional of the preformed piece with a secondary material installed in the secondary area and with the additional injection molded material molded behind the preformed piece. 
         FIG. 11  is a cross-sectional view of the door panel illustrated in  FIG. 2  with a simulated deck seam and stitch adjacent to a leather insert in the secondary area. 
         FIG. 12  is a cross-sectional view of the preformed piece in  FIG. 8  with a tear seam formed by scoring the injection molded material, the back skin, the foam area, and the top skin. 
         FIG. 13  is a cross-sectional view of the preformed piece in  FIG. 12  after the deployment of a device, such as an airbag, provided behind the preformed piece. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a vehicle  10  is shown that includes an airbag system and door panels. The airbag system includes an airbag that is configured to inflate and deploy in an impact to protect an occupant of the vehicle. Airbags may be provided for the driver and/or the passengers of the vehicle and may be deployed from a variety of interior components, such as seats, panels or other structures. When activated, the airbag is generally configured to deploy from an interior panel or structure through a deployment door or portion that separates from the main body of the interior panel or structure. While the vehicle  10  is shown as a four-door sedan, it should be understood that the interior panel described in this application may be used in a wide variety of vehicles (e.g., automobiles such as cars, trucks, buses, and the like; airplanes, boats, etc.). 
     Airbags are typically mounted in housings within a steering wheel, or instrument panel, or another interior panel or structure, such as a door panel. The airbag is typically housed behind a pair of doors or a portion of the panel that is configured to separate from the main body of the panel when the airbag is deployed. The deployment doors or portion is configured to safely allow the airbag to deploy through the interior panel or structure. The deployment doors or portion may be designed to match a decorative theme for the vehicle. 
     The deployment doors or portion are coupled to the main body of the interior panel or structure by a hinge and are typically configured to separate along a tear seam. The tear seam has a reduced tensile strength relative to the surrounding portions of the interior panel and provides a weakened place in the interior panel that allows a deploying airbag to break through. When the airbag deploys, the tear seam ruptures and allows the airbag to fully inflate. The tear seam may be formed on the front or “A” side of the panel or on the back or “B” side of the panel. The tear seam is preferably provided on the “B” side so that it is hidden by a corresponding seam on the “A” side. 
       FIG. 2  illustrates one exemplary embodiment of trim panel, a component or assembly such as a door panel or other structure for use in a vehicle (e.g., automobiles such as cars, trucks, buses, and the like; airplanes, boats, etc.). Such components may be provided in a wide variety of sizes, shapes, and configurations according to various exemplary embodiments. For example, such components may be utilized in an interior passenger compartment of a vehicle, and may find utility in the form of door panels, dashboards, instrument panels, consoles, sidewall trim, overhead liners, or other vehicle components or portions thereof. The exemplary component is a trim panel  100 , a door panel is shown, but other interior components may include the below described features. These components may include for example an instrument panel. The door panel  100  includes one or more localized or discrete portions  112  (e.g., areas, regions, etc.) of softness or cushion that have stitching  113  (e.g., seam, embroidery, and/or other sewn portion, which will collectively be referred to as stitching  113 ). The door panel is provided with cushioning in portions  112  where a portion of a passenger&#39;s body may or is likely to contact the door (e.g., on an armrest, adjacent a window sill, etc.). The door panel  100  may also include one or more portions  118  (e.g., areas, regions, islands, etc.) of hard plastic in areas not typically contacted by a passenger. Stitching  113  may provide any of a variety of or combination of decorative, ornamental, and/or functional purposes. 
     The methods of providing localized cushioned portions  112  of softness or cushioning in a manner described herein may be utilized to provide components having a wide variety of configurations and uses. Portion  118  may include bezels, accents, appliqués, pull cups, complex geometries (e.g., ball armrests, x, y, z boundaries, etc.), proud (e.g., raised) or recessed regions of cushioning for enhanced aesthetics, or the like. 
     Referring to  FIGS. 2 and 4 , door panel  100  includes a member or element in the form of a relatively rigid substrate, base, or stratum (referred to herein as a “substrate”  120 ). Cushioned portion  112  is located adjacent or proximate to at least a portion of substrate  120 , and comprises a coverstock  110 , also referred to herein as a preform piece  134 , coupled to substrate  120 . According to an exemplary embodiment, preform piece  134  includes a skin  122 , a filler or compressible material  124  provided intermediate or between skin  122  and a back skin  125 . According to exemplary embodiments, portions of skin  122  may be in direct contact with substrate  120  (i.e., no compressible material  124  between skin  122  and substrate  120 ), while other portions of skin  122  may be separated from substrate  120  by compressible material  124  and back skin  125 . In this manner, selectively varying amounts or degrees of softness or cushioning are provided at one or more localized regions while retaining the look and feel of the skin even in those regions not provided with the additional cushioning of compressible material  124 . The particular design chosen may depend on any of a variety of factors, including the desired look and feel of the outer surface of the panel, materials costs, ease of manufacturing, etc. 
     According to an exemplary embodiment, the cushioned portion  112  as part of the preform piece  134  is disposed on or over at least a portion of substrate  120 . Skin  122  forms at least a portion of the exterior surface (e.g., the portion visible from a passenger compartment, which is typically referred to as the “A” surface or side) of the component. According to an exemplary embodiment, a portion  126  of substrate  120  not covered by coverstock  110  may also form a portion of the exterior surface (“A” surface). 
     The preform piece  134  is prepared, typically by a molding process, as a trilaminate preform piece. The top skin  122  can be composed of polyvinylchloride (PVC) or a thermoplastic polyolefin. The center layer  124  is typically a polyolefin foam that is compressible. A back skin  125  is typically a thermoplastic polyolefin. The three layers are introduced into a mold and thermally formed to a desired configuration. 
     As illustrated in the figures, the preform piece  134  is a part of a vehicle door panel  100 . During the molding process of the preform piece  134 , an insert (not shown) is placed in the negative forming tool of the mold to create a sharp creasing detail  136  at a preselected position. Alternatively, the step can be created by configuring the negative forming tool. A cross-sectional view of the perform piece is shown in  FIGS. 7 ,  8 ,  9 ,  10 ,  11  and  12  the perform piece  134  may include a crease  136  as well as a trilaminate structure. As shown in  FIG. 7 , a primary area  140  and a secondary area  138  on the preform piece  134  are defined by the crease  136 . As shown in  FIGS. 8 and 9 , a secondary material  128 , also referred to as an insert, can be installed in the secondary area  138  during the molding process of the preform piece  134 . In  FIG. 8 , the secondary material is cloth and in  FIG. 9 , the secondary material is a leather. The secondary area  138  may also include a coating, for example paint. 
     By installing the insert in the negative forming tool, a sharp step, for example 3 mm deep, may be created in the preform piece  134 . That detail is created in the preform piece as seen on the outer skin  122 . During the molding process, as the material behind the skin is injected into the mold, the mismatched step folds onto itself and creates a crease  136  along the step. The crease in the molded part gives the appearance of one skin folded over another skin. Different graining features in the top skin  122  in the primary area and the secondary area can give the appearance of different materials when in fact it is of the same material. It is also contemplated that the secondary area can be painted or coated to give the appearance of a different material. As shown in  FIG. 10 , the pressure exerted on the preform piece  134  during the molding process closes up the crease  136  and makes an extremely tight seam. 
     As shown in  FIG. 11 , a secondary feature can be added to the preformed piece  134  by adding a stitch feature  113  during the formation process. After formation of the preform piece  134 , the substrate  118  may be molded to complete the panel  100 . A cross-sectional view of such structure is shown in  FIGS. 10 and 11 . 
     Any of a variety of configurations may be utilized for the interface of the edges of the skin and the substrate. According to an exemplary embodiment, a flange is formed on skin  122  by forming in a vacuum mold (e.g., to provide an edge of the skin with a “folded back” configuration to form a protrusion). Substrate  120  is then molded around flanges of skin  122  (and compressible material  124 ). According to a preferred embodiment, preform piece  134  and substrate  120  are coupled together such that a relatively airtight and/or watertight seal is provided. 
     Substrate  120  provides a base or support layer for preform piece  134 , including the skin  122 , and compressible material  124  and back skin  125 . Substrate  120  may be made of any suitable material, including any of a variety of polymers (e.g., polypropylene, polyethylene, copolymers, compressed fibers, TPO, filled plastics, polycarbonate ABS blends, ABS, or any of a variety of other materials). Substrate  120  may be formed in any of a wide variety of shapes, sizes, and configurations (see, e.g.,  FIG. 2 , which shows door panel  100  according to an exemplary embodiment having regions of localized cushioning), and may include a variety of other features (e.g., apertures for door locks and handles, molded-in designs, etc.). Substrate  120  may be formed by any of a variety of methods, including injection molding, thermoforming, or the like. Portions of substrate  120  that form part of the “A” surface may have any of a variety of textures, colors, indicia, features, and the like. Substrate  120  may be a stand-alone component or may be a component in a larger assembly (e.g., the substrate may be an entire door panel or may be a portion thereof, etc.). 
     According to an exemplary embodiment, skin  122  is made of a relatively soft or flexible material comprising a polymeric material (e.g., a thermoplastic olefin (TPO), polyurethane, polyvinylchloride (PVC), etc.). According to other exemplary embodiments, skin  122  may be made of other materials, including textiles such as cloth, leather, composite materials, layered materials such as a secondary material  128 , also referred to as an insert (e.g., a layer of leather applied above a polymeric material layer), etc. Preform piece  134  (e.g. PVC or TPO top skin  122 , compressible material  124 , and TPO back skin  125 ) may have a size, shape, and configuration that is adapted or configured to features included in substrate  120 . Skin  122  may be manufactured or produced utilizing any of a variety of process. According to an embodiment, skin  122  (e.g., a TPO sheet) is thermoformed (e.g., vacuum formed, pressure formed, etc.) and then trimmed to a desired shape or configuration. In a vacuum molding process, a pre-cut or formed sheet of polymeric material is provided in a mold and heated to soften the material. A vacuum is applied to the mold, which draws the softened polymeric material toward the walls of the mold. The polymeric material then cools and maintains the shape defined by the mold walls. The formed sheet may also be trimmed for desired size. According to an alternative embodiment, the skin is formed by a slush molding process wherein thermoplastic material in a liquid or powdered form is introduced into a temperature-controlled mold to form a viscous skin adjacent to the mold walls; once the skin is formed, the excess material is removed from the mold and the skin is allowed to cure and cool, after which the skin is removed from the mold. According to other alternative embodiments, preform piece  134  is manufactured according to various other methods. For example, the preform piece  134  may be formed in an injection molding process, an extrusion process, a casting process (e.g., gravity casting), or any other suitable process for forming a polymeric skin. 
     According to an exemplary embodiment, compressible material  124  is coupled (e.g., bonded, fused, adhered, fastened, attached, etc.) to skin  122  and located in between skin  122  and back skin  125  to act as a “filler” or soft layer. It is intended that such material acts as a relatively soft or cushioning material to provide the cushioned member with at least a portion of its relatively soft or cushioned characteristic. According to a preferred embodiment, the compressible material is a polymeric material such as a foam material (e.g., urethane foam, closed cell foam, open celled foam, etc.). The back skin  125  can be any suitable material compatible with the compressible material  124  and the substrate material  120 . According to an alternative embodiment, stitching  113  is applied to skin without having a compressible  124  (i.e., to provide a different level of softness). As such, stitching  113  may be provided to skin  122  with compressible material, skin  122  without compressible material  124 ; and the thickness of the skin layer, the compressible material layer and the back skin may be varied according to the desired softness. 
     Stitching  113  is applied to skin  122  or (preferably) to a laminate of skin  122 , compressible material  124  and back skin  125  proximate a crease detail  136 . Stitching  113  may be applied by any of a variety of conventional techniques (e.g., hand sewn, machine sewn, etc.). Stitching  113  may be made from any of a variety of materials, such as fabric, textile (e.g., cotton), polymer (e.g., nylon, etc.), or other material which may or may not melt or liquefy upon application of heat. Applying stitching  113  to the preform piece  134  including an insert  128  before substrate  120  is molded is intended to recess stitching  113  in skin  122  and/or compressible material  124 . During molding of substrate  120 , compressible material  124  is compressed by the injection of the molten resin that forms substrate  120  (see  FIGS. 9 and 10 ). Stitching  113  compresses less (and preferably substantially less) than compressible material  124  and/or skin  122  such that skin  122  and compressible material  124  are forced around stitching  113 . During the molding process, substrate  120  bonds (e.g., mechanically and/or chemically (e.g., thermally or fusion)) to preform piece  134 . When the molded article is removed from the mold tool or fixture, compressible material  124  expands (and around stitching  113 ) to provide the visual effect that stitching  113  is recessed (e.g., providing a “quilting” or a contour change with the appearance that that portion of the trim panel is cushioned). 
     In an exemplary embodiment, a device  150 , such as an airbag system, is installed in a volume space behind the trim panel  100 , for example in an instrument panel or a door panel. The trim panel  100  is configured to rupture to allow the device to deploy. 
     As shown in  FIG. 12 , a tear seam  142  is formed along seam  136  between the primary area  140  and secondary area  138 . Tear seam  142  is formed by scoring or cutting substrate  118 , back skin  125 , and filler  124  and skin  122 . According to an exemplary embodiment, tear seam  142  is formed with a laser scoring process but may be formed by any suitable scoring process (e.g., mechanical scoring, etc.). Tear seam  142  is an area between secondary area  138  and primary area  140  that allows secondary area  138  (e.g., the deployment door or portion) to move relative to primary portion  140  during the deployment of the device  150 , for example an airbag system. The deployment of the secondary portion  138  allows the airbag to inflate or deploy into the interior of the vehicle as shown in  FIG. 13 . Seam  136  provides an overhang that hides tear seam  142  and any deformation of skin  122  that may be caused by secondary area  138  shifting slightly relative to primary area  140 . Secondary area  138  may be configured to deploy in a variety of manners to allow the airbag to inflate into the interior of the vehicle. For example, tear seam  142  may be configured to act as a hinge or may be configured to rupture under the forces of the inflating airbag. A single deployment door may be provided on panel  100  for the airbag or two or more deployment doors may be provided that cooperate to allow the airbag to inflate into the interior of the vehicle. 
     For purposes of this disclosure, the term “coupled” means the joining of two components (electrical or mechanical) directly or indirectly to one another. Such joining may be stationary in nature or movable in nature. Such joining may be achieved with the two components (electrical or mechanical) and any additional intermediate members being integrally formed as a single unitary body with one another or with the two components or the two components and any additional member being attached to one another. Such joining may be permanent in nature or alternatively may be removable or releasable in nature 
     It is also important to note that the construction and arrangement of the elements of the vehicle trim panel as shown in the preferred and other exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited in the claims. For example, the compressible material may be coupled to the skin and positioning the skin and compressible material in a mold; and forming a rigid substrate around the skin and compressible material providing a first soft region wherein the compressible material is disposed between the skin and the substrate so that a first soft region is defined by the compressible material. Stitching may be provided on either the portion of the skin adjacent the first shot, or the second shot, or the third shot, or the like. The substrate may comprises a molded polymer material such as a thermoplastic. The skin may comprise a thermoplastic olefin and be formed by vacuum forming and trimming a sheet. The compressible material may comprise a foam material such as a closed cell foam. The skin may comprise flanges so that the substrate can be molded to at least partially encapsulate the flanges. A second soft region may be defined by a portion of the skin in direct contact with the substrate (e.g., the compressible material is not disposed between the skin and the substrate). The molding technique may also be employed in other application besides for vehicle interiors. Accordingly, all such modifications are intended to be included within the scope of this application. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and/or omissions may be made in the design, operating conditions and arrangement of the preferred and other exemplary embodiments.