Abstract:
A laser inspection fixture for facilitating visual inspection of attachments to an object such as adhesive, sealant, wax or mastic daubs or lines on the article in a manufacturing process. The intended location of each object is illuminated by one laser that is provided with a dot profile template. The fixture may also be used to facilitate visual inspection of production tools and dies to verify tool set-up configurations.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates to a multi-point inspection station for visually verifying the presence and location of paste-like materials, tool set-up pins, and other items that are applied or attached to an object. 
       BACKGROUND 
       [0002]    Visual inspection is one way of checking the location and presence of wax, sealer, adhesives fasteners, pins, or other objects that are applied, attached, or assembled in a production operation. A sample, exemplar, or template may be used as a visual guide for a visual inspection station. An inspector is expected to check the production part in a visual inspection in view of the sample part or template. 
         [0003]    Sealers, adhesives, and wax are increasingly being used in vehicle assembly operations. These types of paste-like consistency materials are not as easy to check as a rivet or fastener that can be checked by sensors in the tool or by machine vision systems because they are precisely located and have a uniform appearance when installed. However, an adhesive deposit can flow or move as a result of gravity or forces exerted on the deposits as they are moved between stations or during application. The amount of lubricant or other coatings on a surface may also result in variation in adhesive location. These types of paste-like deposits do not always have the same appearance and are not easily checked with machine vision systems that are too sensitive which may result in excessive false alarms. 
         [0004]    Vehicle doors, deck lids, hoods, and roofs may receive mastic, sealer, sound deadener, or wax applications in spots or lines that must be accurately applied to predetermined locations to be effective in joining outer body panels to inner panels and reinforcements. It is very difficult to visually verify the location and presence of a large number of deposits of such materials in a production environment without stopping the production line and using a tape measure to check the location of the deposits. If an adhesive or other application is missed, falls off, or is off location, subsequent remedial measures may need to be taken, at considerable expense, to correct the problem caused by the lack of the deposit in the proper location. 
         [0005]    Visual inspection of die bolster pad pins and other tooling fixtures used in production operations is also difficult when a large number of points of inspection must be checked. After a die or fixture is set-up, a tedious verification of the tool set-up against tooling specification drawings must be performed to assure that the tool is properly set-up. For example, operation of a cushion die pad to produce parts may be impaired and may result in the improper production of parts if a die pad has a cushion pin that is placed in the wrong location or omitted. 
         [0006]    This disclosure is directed to solving the above problems and other problems encountered in situations where visual inspections are employed as summarized below. 
       SUMMARY 
       [0007]    According to one aspect of this disclosure, a visual inspection fixture is provided for inspecting a plurality of locations on an object for the presence and location of a plurality of attachments. The fixture comprises a support frame and a plurality of lasers secured to the fixture that are each directed towards one of the plurality of locations to illuminate an area associated with each location. 
         [0008]    According to other aspects of this disclosure, a controller selectively provides power to the lasers when a visual inspection is conducted. A plurality of dot profile templates are each attached to one of the lasers to project a line around each of the plurality of locations to facilitate a visual inspection for verifying that the attachments are all properly located on the object. The line may extend around each of the plurality of locations and may be enlarged to include an acceptable tolerance for the location of the attachments. 
         [0009]    The support frame may include a plurality of parallel bars arranged side-by-side with the lasers being attached to the bars to be aimed at one of the plurality of locations. The lasers may be secured to the bars by an adjustable retainer that facilitates adjusting the location towards which each of the lasers are directed. 
         [0010]    The attachment may be a line of material applied to the object, and the lasers may be directed to a plurality of locations along the line of material to facilitate a visual inspection of the location and presence of the line of material. Alternatively, the attachment may be a daub of paste-like material applied to the object. The material may be selected from a group including but not limited to adhesive, sealant, wax, and mastic. 
         [0011]    In another application for the disclosed fixture, the object may be a tool that is adapted to receive a plurality of attachments selected ones of a plurality of locations. Each of the lasers may be directed towards one of the locations where one of the attachments are to be attached. In a specific application, the object may be a bolster plate for a die that includes a plurality of pockets, and wherein a sub-set of the pockets are selected to receive a press pin. Each one of the lasers is secured to the fixture to be directed towards one of the sub-set of the pockets to illuminate one of the pockets that was to receive one of the pins. 
         [0012]    According to another aspect of this disclosure, a system is disclosed for visually inspecting a plurality of locations on an object. The system comprises projecting focused light in a pattern to illuminate each of the locations on the object. Each of the locations is visually inspected for the presence and the location of certain attachments that are intended to be disposed at each of the locations. 
         [0013]    According to other aspects of the system the focused light may be the light from a laser. The light from the laser may be projected through a dot profile template to project a pattern of light that may form a line of light extending about the locations. The focused light may be provided by a plurality of lasers that each illuminates one of the locations on the object. 
         [0014]    According to additional aspects of this disclosed system, the attachments may be daubs of paste-like material applied to the object. The material may be adhesive, sealant, wax, or mastic. 
         [0015]    According to yet another aspect of this disclosure, a method is disclosed for visually inspecting an object that receives at least one attachment. The method comprises directing light focused on a plurality of locations on the object to provide illumination proximate the attachment at each of the plurality of locations. The attachments are visually inspected to determine the presence and the location of the attachments at each of the locations. 
         [0016]    According to one application of the method, the attachment may be a daub of paste-like material applied to the object, and the light focused on the plurality of locations may be provided by a plurality of lasers that each illuminate one of the locations on the object. 
         [0017]    According to another application of the method, the object may be a bolster plate for a die that includes a plurality of pockets. The attachment may be a press pin and a sub-set of the plurality of pockets may be selected to receive one of the press pins. The method may further comprise securing each of a plurality of lasers to a fixture to be directed towards one of the sub-set of pockets and illuminating each one of the pockets selected to receive one of the press pins. The step of visually inspecting may further comprise inspecting for the presence and the location of the press pins in the sub-set of pockets. 
         [0018]    The above aspects of this disclosure and other aspects are described in greater detail below with reference to the attached drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a perspective view of a laser visual inspection fixture; 
           [0020]      FIG. 2  is a diagrammatic view of a laser and a dot profile template; 
           [0021]      FIG. 3  is a fragmentary perspective view of an object, such as an inside surface of an outer panel for a vehicle having a plurality of daubs of a paste-like material applied in a predetermined pattern in locations highlighted by a set of rings of illumination; 
           [0022]      FIG. 4  is a top plan view of a roof panel having a line of sealant applied around a skylight opening with dots of laser light projected adjacent the line of sealant; 
           [0023]      FIG. 5  is a diagram of a press pin hole chart showing a desired arrangement of press pins in a die as they are specified to be assembled to a die bolster; and 
           [0024]      FIG. 6  is a perspective view of a press including a die bolster having press pins installed in the bolster as the bolster is being inspected by the laser visual inspection fixture. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    A detailed description of the illustrated embodiments of the present invention is provided below. The disclosed embodies are examples of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale. Some features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed in this application are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art how to practice the invention. 
         [0026]    Referring to  FIG. 1 , a visual inspection fixture  10  includes a support frame  12 . A plurality of lasers  14  are attached to a plurality of parallel bars  16  that are supported by the support frame  12 . The lasers  14  are connected to the parallel bars  16  by adjustable retainers  18 . The lasers  14  are directed to a predetermined location on an object and locked into place by the adjustable retainers  18 . The visual inspection feature  10  is operatively connected to a controller  20 . The controller  20  is used to turn the lasers  14  on to conduct a visual inspection of an object, as described below with reference to  FIG. 3 . 
         [0027]    Referring to  FIG. 2 , a laser  14  is shown diagrammatically with a dot profile template  22  that limits the light emitted from the laser  14  to a circle of light or other shape corresponding to the shape of a desired attachment  26  (as shown in  FIG. 3 ). The laser  14  is secured to the fixture (shown in  FIG. 1 ) by an adjustable retainer  18 . 
         [0028]    Referring to  FIG. 3 , a section of a panel, such as a vehicle door, deck lid, roof or hood is illustrated with a plurality of attachments  26  disposed on the object  24 . In  FIG. 2 , the illustrated attachments  26  are daubs of a paste-like material and may include adhesives, mastics, sealants, waxes and the like that are used in automotive component assembly operations. For example, adhesives may be used to augment other assembly techniques, such as welding, riveting and clinching. Adhesives are important in connecting inner panels and reinforcements to outer panels. The outer panels generally define class A surfaces that are painted and must be provided with a smooth surface that is not interrupted by attachment devices. 
         [0029]    As shown in  FIG. 2 , the daubs of material or attachments  26  are shown within or at locations generally indicated by an illumination line  30 . In  FIG. 2 , for example, several daubs  26  are shown partially outside of the illumination line  30 . Some of the unacceptable daub locations  26  are indicated by an “X” in  FIG. 2 . 
         [0030]    The illumination lines  30  are projected by the lasers  14  (shown in  FIGS. 1 and 2 ) with one laser  14  being used to project each illumination line. In the illustrated embodiment, the illumination lines  30  are either oval or circular and are larger than the daubs  26 . The illumination lines  30  are sized and shaped to include a tolerance area corresponding to the tolerance in the location of the daubs  26  that is added to the size of the intended daub of material. 
         [0031]    Referring to  FIG. 4 , a roof panel  32  is illustrated that defines a skylight opening  34 . A sealant ring  36  is deposited around the periphery of the skylight opening  34  on the roof panel  32 . In this particular inspection operation, an inspector visually inspects the location of the sealant ring  36  to be sure that it does not include any portion that extends too far outside of the skylight opening  34 . A plurality of dot laser projections  38  are projected by the lasers  14  in selected locations where the alignment of the sealant ring  36  may be visually checked. 
         [0032]    Referring to  FIG. 5 , a press pin hole chart  42  is provided that is used by die setters to set the location of press pins  44  on a cushion pad bolster  46  for a die before the die is loaded into a press for production purposes. The press pin hole chart includes, in the illustrated embodiment,  150  potential press pin locations along the X-axis and 66 press pin locations located along the Y-axis. The large number of potential press pin hole locations makes it time consuming and tedious to install the press pins  44  in the bolster  46  and then check to be sure that the press pins  44  are all located in the proper hole. 
         [0033]    Referring to  FIG. 6 , a press pin  44  installation on a bolster  46  of a press cushion is shown in a position ready to be installed in a press  48 . Prior to installing the bolster  46  with the press pin  44  in the press, a visual inspection fixture  10  may be used to check the location of the press pins  44 . As described with reference to  FIG. 1 , the visual inspection fixture  10  includes a plurality of lasers  14  that are each projected on one of the intended press pin  44  installation hole locations. By projecting a beam of laser light onto the intended press pin locations, the press pin  44  installation can be visually checked with increased certainty. 
         [0034]    While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.