Abstract:
In at least one implementation, a method for forming openings for a stitched seam in a composite panel having an outer layer, and a substrate behind the outer layer includes providing a laser beam onto the substrate, with the laser beam forming an opening through the substrate but not through the outer layer, and moving at least one of the laser or the substrate relative to the other so that a new opening can be formed that is spaced from the already formed opening. Successive openings can be formed in desired locations around the panel to facilitate subsequent panel stitching. In at least some implementations, the laser may form such openings while stitches are formed in the panel, wherein a stitch is provided in a previous opening while or nearly at the same time the laser forms a different opening for a subsequent stitch.

Description:
FIELD 
     The present disclosure relates to an apparatus and method for stitching a composite panel, such as may be used in an automotive interior. 
     BACKGROUND 
     Automotive vehicles typically include interior trim components mounted to and hiding various interior structural components and accessories. The trim components may be provided in many shapes and sizes and often include composite or multilayered materials. Certain design elements, like stitches may be desired in a composite material, like a panel for a dashboard or interior door panel. 
     SUMMARY 
     In at least one implementation, a method for forming openings for a stitched seam in a composite panel having an outer layer, and a substrate behind the outer layer includes providing a laser beam onto the substrate, with the laser beam forming an opening through the substrate but not through the outer layer, and moving at least one of the laser or the substrate relative to the other so that a new opening can be formed that is spaced from the already formed opening. Successive openings can be formed in desired locations around the panel to facilitate subsequent panel stitching. In at least some implementations, the laser may form such openings while stitches are formed in the panel, wherein a stitch is provided in a previous opening while or nearly at the same time the laser forms a different opening for a subsequent stitch. 
     In at least one implementation, a method for providing a stitch in a composite panel having an outer layer, and a substrate beneath the outer layer includes providing a substrate for the panel that has an opening therethrough and providing an outer layer for the panel that overlies the substrate and does not have an opening aligned with the substrate opening. An opening is pierced in the outer layer with a needle carrying thread at a location aligned with the substrate opening so that the needle enters the substrate opening after piercing though the outer layer and so that the thread is pushed through both the outer layer and the substrate via the openings in the outer layer and substrate. 
     An apparatus for providing a stitch in a panel including an outer layer and a substrate behind the outer layer may include a needle carrying thread to provide the stitch in the panel, the needle moveable between retracted and advanced positions where the needle penetrates the outer layer before entering the substrate when moved from its retracted to its advanced position; and a laser. The laser is located to direct a beam at the substrate and form an opening in the substrate without forming an opening through the outer layer. The laser and needle may be located in the same general workstation or work area so that, as the panel is moved relative to the needle to form successive stitches in the panel, the panel is also moved relative to the laser to form successive openings in the substrate. Desirably, the same indexed movement of the panel that is used to form the stitches is also used to provide the laser formed openings. In this way, the substrate openings may be spaced and located as desired for the stitches. 
     Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings provided hereinafter. It should be understood that the summary and detailed description, including the disclosed embodiments and drawings, are merely exemplary in nature intended for purposes of illustration only and are not intended to limit the scope of the invention, its application or use. Thus, variations that do not depart from the gist of the disclosure are intended to be within the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a somewhat diagrammatic perspective view of an apparatus for stitching a component; and 
         FIG. 2  is a diagrammatic sectional view of an apparatus for stitching a component. 
     
    
    
     Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings provided hereinafter. It should be understood that the summary and detailed description, including the disclosed embodiments and drawings, are merely exemplary in nature intended for purposes of illustration only and are not intended to limit the scope of the invention, its application or use. Thus, variations that do not depart from the gist of the disclosure are intended to be within the scope of the invention. 
     DETAILED DESCRIPTION 
     Referring in more detail to the drawings,  FIG. 1  illustrates an a stitching apparatus  10  that provides stitches  12  into a panel  14  or component, such as an interior trim piece which may be associated with an instrument panel, or other component for an automotive vehicle. The stitches may be decorative (e.g. on opposed sides of a faux seam formed in a single piece of material to simulate a junction of two pieces of materials) or functional (e.g. to join two adjacent pieces of material at a seam), as desired. 
     In one form, as best shown in  FIG. 2 , the panel  14  is a multi-layer composite that includes an outer layer  16 , a structural substrate  18  and an intermediate layer  20  sandwiched between the outer layer  16  and substrate  18 . The outer layer  16  may be exposed within the vehicle interior and made of any desired material, such as a molded polymeric material or leather. Typical outer layers  16  are formed from TPO, PVC and TEO, and may be 0.6 to 1.3 mm thick. The intermediate layer  20  may be adhered to the outer layer  16 , if desired, and may have any desired firmness and thickness to, for example, provide a desired thickness and overall tactile feel for the panel  14 . Typical intermediate layers  20  are comprised of foam such as polyurethane and may be between 4 to 12 mm thick. The substrate  18  may be a more rigid layer and may be formed of any suitable material such as PPO and may be glass filled or otherwise reinforced, if desired. The substrate  18  may act as a base for and provide increased structural integrity to facilitate forming, handling and/or installing the panel  14 , and/or to inhibit sagging, wrinkling or other movement of the outer layer  16 . While so far described and shown with three layers, the panel  14  may have more or fewer layers and/or a portion of a panel may have a different number of layers than a different portion of the same panel. 
     As shown in  FIG. 1 , the panel  14  is provided with stitches  12  by a sewing apparatus  10 . The apparatus  10  includes a needle  22 , an actuator  24 , and a shuttle  26 . The needle  22  may be of conventional construction and adapted to engage and push thread  28  into the panel  14  as will be described. The actuator  24  may be any suitable mechanism(s) that drives the needle  22  between a retracted position spaced from the panel  14  and an advanced position with at least a portion of the needle penetrated into the panel. The actuator  24  may include any suitable sewing machine mechanisms and be of conventional construction. The shuttle  26  may also be of conventional construction and may include any mechanism adapted to move the panel  14  relative to the needle  22  to facilitate application of successive stitches  12  into the panel. The term “shuttle” should not be interpreted to make any particular structure or mode of operation necessary simply because certain or even all shuttles have such structure or mode of operation. 
     As shown, the actuator  24  includes a head  30  that engages the outer layer  16  during the stitching process to hold the outer layer in a desired position during stitching. Openings  32  through the head  30  adjacent to the needle  22  may receive the needle and guide its movement. Also, as shown in  FIG. 1 , two needles  22  may be provided with each needle adapted to provide a separate row of stitches  12  to provide two spaced apart rows of stitches. In at least some implementations, the rows of stitches are provided with one row on each of two sides of a seam  33  (faux or genuine seam). The shuttle  26  includes one or more supports  34  that may engage the panel  14 , and are shown as engaging the substrate  18 , to position and hold the panel as the needles  22  are moved to their advanced position, and then advance the panel  14  relative to the needles when the needle is moved sufficiently toward or all the way into their retracted position. Looper devices  35  driven by a suitable actuator  37  may provide a second thread  39  ( FIG. 2 ) to effect a typical lock or chain stitch, as desired. Other structures, devices and stitch types may be provided in addition to or instead of those noted herein. 
     Stitches  12  may be provided in the panel  14  by the needles  22  and other mechanisms at a workstation  36 . The workstation  36  may also include one or more laser generators  38  arranged to form openings  40  in the panel  14  to facilitate the stitching process. The laser generator(s)  38  may direct a laser beam  42  at the panel  14  to form one or more openings  40  in at least the substrate  18 . As shown in  FIG. 2  (which is simplified and does not show the shuttle, looper devices and other such devices), in at least some implementations, the laser beams  42  may form successive, separate openings  40  that extend all the way through the substrate  18 . In at least some implementations, the openings  40  do not extend through the outer layer  16  which is instead pierced by the needles  22  during the stitching process. The openings  40  may extend into, through or not at all into the intermediate layer  20  (or intermediate layers where more than one is provided). To achieve this, the intensity/power of the laser beam  42  provided by the laser generator  38  may be variable and controllable in at least certain implementations, to permit use with different panels  14  and different substrates  18  and to permit improved control of the depth of the openings  40  in the panel. In the implementation shown in  FIG. 1 , two laser beams  42  are provided onto the panel  14  to form separate rows of openings  40  that correspond to the separate rows of stitches  12  provided in the panel  14  by the two needles  22 . That is, each laser beam  42  and hence, each row of openings  40 , may be aligned with one needle  22 . 
     In at least some implementations, the substrate openings  40  are formed generally at the same time that the panel  14  is stitched, with the substrate openings being formed at some time before the needles  22  enter their respective substrate openings  40  during the stitching process, as will be described in more detail later. The amount of time that a given substrate opening  40  is formed before a needle  22  enters that substrate opening can be varied, as desired. In at least some implementations, the openings  40  will be formed in the area of the supports  34  that engage and hold in position the substrate  18  near the actuator head  30 . In this manner, as the panel  14  is advanced for successive stitches  12 , the laser beams  42  can be controlled to provide successive openings  40  in the substrate  18  that correspond with the position of stitches to be made in the panel. That is, relative to the direction of movement of the panel  14 , the substrate openings  40  may be formed upstream of the needles  22 , and upstream of a location where a stitch  12  is applied to the panel  14 . Thus, the same mechanisms and movement that registers the panel  14  with the needles  22  during successive stitches  12  may also register the panel  14  with the laser  38  to ensure accurate spacing and alignment of the substrate openings  40  and the needles, with the same apparatus used for the stitching process. In some implementations, the openings  40  may be formed within 2 mm or less from the location where the needles  22  penetrate the panel to apply a stitch to the panel. Or course, in other embodiments, the openings  40  may be formed farther away from the location of stitch application and may even be formed prior to the panel  14  being registered with the sewing apparatus  10 . Other implementations may include forming the substrate openings  40  before the intermediate and outer layers  20 ,  16  are connected to the substrate  18 , if desired. 
     Regardless of when the substrate openings  40  are formed, the substrate openings may be provided before the needles  22  penetrate or are inserted into the substrate  18 , and the substrate openings may be used to register/align the panel  14  and needles  22  to ensure accurate needle and stitch placement within the panel. This may reduce snags or other strain on the thread  28  and avoid or reduce the likelihood that the thread will break during the stitching process. The substrate  18  may be worked on after the substrate openings  40  are formed and before the thread  28  is inserted into the substrate openings to further reduce the likelihood that the thread will break during stitching. Such optional work may include sanding, reaming, drilling, deburring or other operations as desired to improve or ensure the quality, location, orientation and/or size of the opening. In at least certain implementations, no such optional work may be needed when a laser formed opening can be provided free of significant burrs or other anomalies that may negatively affect the threads  28 ,  37 . Further, the openings  40  through the more rigid substrate  18  reduce the stress on the thread  28  and the force needed to move the needles  22  through the substrate  18  to further improve the stitch  12  (e.g. prevent undue bagging or sagging of the panel/stitches, or the thread pulling on the outer layer too much) and reduce the likelihood that the thread  28  will break during stitching. At least in applications where undue stress is not applied to the thread  28  when a needle  22  pierces the outer layer  16  and/or intermediate layer  20 , these layers need not have any preformed opening for a satisfactory stitch  12 . With at least some substrates  18 , the substrate openings  40  may be at least as large as the needle diameter, and in some implementations, the substrate openings may be larger than the needle to reduce friction between the substrate and needle which generates heat that may cause thread breakage and thread stress. 
     A method for providing a stitch in a composite panel having an outer layer and a substrate beneath the outer layer may include: 
     providing a substrate for the panel that has an opening therethrough; 
     providing an outer layer for the panel that overlies the substrate and does not have an opening therethrough aligned with the substrate opening; and 
     piercing an opening in the outer layer with a needle carrying thread at a location aligned with the substrate opening so that the needle enters the substrate opening after piercing though the outer layer and the thread is moved through both the outer layer and the substrate via the openings in the outer layer and substrate. The process may be repeated, with successive openings pierced by the needle and aligned with successive openings in the substrate to provide successive stitches in the panel. The method may also include forming the substrate opening(s) with a laser and this step may be accomplished at any time prior to insertion of the needle into the substrate during the panel stitching. Of course, other methods may be used.