Patent Application
20230041610
The present disclosure relates generally to an interior trim system, and more particularly to an over-molding system and method for manufacturing an interior trim panel.
Traditionally, automotive vehicle interior trim panels, such as those used in center consoles, instrument panels, door panels and pillar panels, have soft-feel outer skins covering a rigid injection molded substrate, often with a flexible foam injected therebetween. Skins for such interior trim panels are typically polyvinyl chloride (“PVC”), thermoplastic polyurethane (“TPU”), thermoplastic polyolefin (“TPO”) or thermoplastic elastomers (“TPEs”). Furthermore, these conventional skins are made by slush rotational molding or thermoforming. Examples of three-step slush molding are disclosed in U.S. Patent Publication No. 2017/0240736 entitled “Polyvinylchloride for Seamless Airbag Doors” invented by Farrar, and U.S. Pat. No. 7,560,515 entitled “PVC Alloy for Use in Air Bag Doors” which issued to Tansey on Jul. 14, 2009, both of which are incorporated by reference herein. Such conventional slurry and foamed panels, however, require many different molding tools, and are expensive and time consuming to manufacture.
Thermoforming first makes a substrate by injection molding then vacuum forms a skin thereto in a separate machine. As a second step, an edge folding machine wraps the skin around the edges of the substrate. Then the excess folded skin is removed by cutting, all of which is time consuming and prone to many tolerance variations.
Various other multilayer configurations have been attempted for making two-shot interior trim panels which first injection or thermoform mold a substrate and subsequently inject another material into the same cavity. Examples of such a two-shot method are disclosed in U.S. Pat. No. 8,088,318 entitled “Method for Processing an Interior Trim Component” which issued to West et al. on Jan. 3, 3012; U.S. Pat. No. 7,572,401 entitled “Insert Molded Bolster in Two-Shot Door Panel” which issued to Cowelchuk et al. on Aug. 11, 2009; and U.S. Pat. No. 5,824,251 entitled “Method for Forming Plastic Molded Panels with Inserts” which issued to Morrison et al. on Oct. 20, 1998. All of these patents are incorporated by reference herein. These traditional approaches, however, all have unsightly raw peripheral edges and/or undesirably require manual folding over and gluing of the outer skin around the peripheral edges of the internal substrate. Moreover, U.S. Pat. No. 9,969,338 entitled “Interior Component” which issued to Kajitani et al. on May 15, 2018, recognizes the problem of unsightly wrinkles and adhesive concerns from difficult skin folding around edges; this patent is also incorporated by reference herein.
In accordance with the present invention, an over-molded interior trim method and system are provided. In another aspect, a method of manufacturing a trim panel includes: injecting a liquid substrate polymer between molds to create a substrate, injecting a liquid urethane polymer into a cavity directly against the substrate to create a skin or cover, flowing or wrapping in a mold the urethane polymer around at least one peripheral edge of the substrate, and extending the urethane polymer onto a backside of the substrate. A further aspect includes damming a flow of an encapsulating urethane skin within the cavity by the liquid urethane abutting against a wall surface upstanding from the backside of the substrate. Yet another aspect of the present system includes an edge wrapped portion of a skin cover spanning across both sides of the mold parting line with a Class-A surface portion of the skin cover being on one side of the parting line and a backside portion of the skin cover being on another side of the parting line. Another aspect of the present system includes mold-wrapping a skin around a peripheral edge of a substrate with the skin having a soft feel and more resilient durometer as compared to the more rigid and thicker substrate. In still another aspect, an over-molded, automotive vehicle trim panel, such as an instrument panel, floor-mounted center console panel, airbag cover, door trim panel, knee bolster, seat mechanism cover panel, pillar cover panel, package shelf panel or the like, includes a substrate with a periphery-encapsulating and soft-feel skin thereon.
The present method and system are advantageous over conventional devices. For example, the present method manufactures an over-molded trim panel in a single cycle, from initial injection mold closure through removal of the cooled and skin-covered final part from the molds, in 2-6 minutes, more preferably in 2-5 minutes, and most preferably in 2-4 minutes, as compared to more than 10 minutes for a traditional substrate molding, slush molding and foaming processing cycle, and as compared to more than 7 minutes for traditional injection molding a substrate, vacuum forming a skin and subsequent manual edge wrapping. The present method and system additionally avoid optional foam-in-place steps which otherwise add complexity, mess, time and expense. Thus, the present method and system are considerably faster, less complicated and less expensive to produce. Furthermore, manufacturing tolerances and accuracy are improved with the present method and system since the substrate remains in a common mold throughout all of the steps.
Also, the present method and system beneficially improve the wrapped edge appearance of the trim panel since conventional manual skin wrapping and the associated wrinkles and unevenness of folds, with adhesive and/or staples are not employed. A soft feel and resiliency of the skin can be achieved by a combination of novel part design, mold design, processing integration and skin material characteristics, while not requiring a separate foaming process between the skin and the substrate. All of these quality, cost and appearance advantages may be realized by synergistically using urethane to encapsulate at least one, and preferably all, peripheral edges of the substrate, while the urethane also extends onto a backside of the substrate. A novel interior trim panel made with the present method is provided, as is a unique mold system construction. Additional features and advantages can be ascertained from the following description and appended claims taken in conjunction with the accompanying drawings.
An interior trim panel for a wheeled automotive land vehicle is shown in
Referring to
Skin 35 has a Class-A appearance outer surface 51 on an outer layer 53, a backside of which being in direct contact with outer surface 37 of substrate 33. Moreover, skin 35 also includes a wrapped or turned end 55 and a return section 57, a backside of which is in direct line-to-line contact with peripheral edge 41 and backside surface 39 of substrate 33, respectively. No adhesives or fasteners (such as staples) are used to secure the skin to the substrate. Thus, skin has a generally J-shaped cross-section (as illustrated in
Substrate 33 is preferably made from a polymeric material primarily including one of: ABS, PC-ABS, SLA or PP. Skin 35 is preferably made from a polymeric material primarily including thermoplastic polyurethane (“TPU”). A nominal middle section of the substrate, after removal from the forming molds, is about 1.5-4 mm thick; a nominal middle section of the skin, after removal from its forming molds, is about 0.5-1 mm thick; and the skin, after removal from the molds, has a Shore A hardness=33-68. Therefore, a majority of the substrate is thicker than is a majority of the skin, at least in the nominal middle sections thereof.
Exemplary polymeric materials suitable for skin are the Elastoskin® 51130R and 51340R resins which may be obtained from BASF. Exemplary and nonlimiting properties of the skin used in the present system are approximately: Shore A hardness=33-90 (more preferably 33-68), Shore A hardness (after 5 seconds)=52-65, tensile strength=9.9-10.2 Mpa, tensile strength at 504 hours and 110° C.=7.5-14.9 Mpa, elongation=292-306%, elongation at 504 hours and 110° C.=316-651%, tear strength=45.9-48.4 kN/m, and tear strength at 504 hours and 110° C.=43.6-64.4 kN/m. Therefore, the skin has a soft feel and is more resiliently compressible to the touch than is the more rigid underlying substrate. Additionally, outer surface 51 of skin 35 preferably has a textured pattern molded therein.
Turning to
Optionally, an aesthetic trim plate or bezel member 85, such as providing a wood grain or chrome appearance, can be in-molded and secured directly to substrate 81 by edge-overlapping skin 83. However, it should be appreciated that an adhesive may temporarily retain member 85 to the substrate until the skin is subsequently added. Alternately, member 85 can be molded in an additional step directly onto an exterior of skin 83 in the same set of tools, or less beneficially, separately stamped or formed and thereafter manually fastened thereto.
An optional fastener or reinforcement bracket member 87 can be in-molded into a backside portion of substrate 81. In this situation, fastener or bracket member 87 is preferably molded in the same set of tools, or alternately separately molded or stamped and then manually inserted into the substrate mold. The substrate is then molded such that a post 89 or other section thereof flows through a hole in member 87 so as to integrally secure it to the backside of the substrate. The manufacturing method and construction of backside member 87 and/or outer member 85 may be used with any of the embodiments disclosed herein.
The tooling and manufacturing process for the center console trim panel (which is also applicable to the other trim panel embodiments) will now be discussed with reference to
Next, movable substrate mold 103 is horizontally opened to the position shown as 103′ relative to stationary substrate mold 101. The cooled and formed substrate is then robotically or manually removed from the molds 101 and 103, and then placed onto a stationary lower skin mold 201 when a moveable upper skin mold 203 is in a vertically raised position as shown in
A skin mixing head or nozzle 123 (in
Subsequently, the liquid skin polymer is injected into the skin cavity. Hence, as the liquid skin polymer flows throughout skin cavity 131, filling up the open space between the outer and edge surfaces of substrate 33 and the skin molds, wall 43 will act as a dam to block the backside flow of the skin polymer, as can best be observed in
If inserts, such as fastener or reinforcement bracket members are used, then they may optionally be directly molded or, alternately separately formed and then inserted, directly into a recess into the substrate mold prior to molding the substrate therein. The present system also encompasses the substrate and/or skin molding tool shapes and configurations themselves. Moreover, the present system also pertains to a trim panel product manufactured according the disclosed methods and processes.
The foregoing description of the embodiments has been provided for purposes of illustration and description, however, variations thereof are envisioned. For example, the trim panels may be differently shaped. Also, while automotive vehicle interior trim panels have been disclosed, trim panels for residential, industrial or recreational use may also employ the present methods and constructions, although some advantages may not be achieved. Furthermore, the present interior trim panel can alternately be used in other transportation vehicles including airplanes, watercraft and train cars. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described, and all of the dependent claims may be multiply dependent in any combination. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are intended to be included within the scope and spirit of the present disclosure.
