Abstract:
In a device for producing and/or processing a workpiece, in particular circuit boards, in a work station, in particular for printing a corresponding blank or for checking finished circuit boards, at least one mark is provided on the workpiece. In this arrangement, at least one reference, which can be brought into alignment with the mark, is provided in the work station.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation application of Ser. No. 14/414,025, filed Jan. 9, 2015, which claims priority to German Patent Application No. 102012106291.9, filed Jul. 12, 2012, and International Patent Application No. PCT/EP2013/064817, filed Jul. 12, 2013, all of which are hereby incorporated by reference in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention relates to a device for producing and/or processing a workpiece, in particular circuit boards in a work station, in particular for printing a corresponding blank or for checking finished circuit boards, where at least one mark is provided on the workpiece, as well as a method for this purpose. 
       BACKGROUND 
       [0003]    Testing devices for examining populated electronic circuit boards for defects and function prior to installation in electronic devices have been both known and commercially available for a long time. In devices of this type, contact pins or needles are pressed onto predetermined sites (contact positions) of the circuit board and then loaded by a test computer with test signals according to a predetermined control to ascertain whether the populated circuit board is functioning properly. To establish perfect electrical contact between the contact needles and contact points on a circuit board which picks off a large number of contact positions, several thousand contact needles are often necessary or possible. 
         [0004]    Testing devices of this type are described, for example, in DE 11 2006 003 034 T5 as well as DE 196 46 252 A1 or DE 44 16 151 B. However, each of these devices requires that the circuit boards being tested are precisely matched to the test pins. The necessity of a plethora of tests of this type being performed within a temporal unit entails considerable problems when positioning the circuit board in relation to the test pins. 
         [0005]    The present invention relates, however, not only to the production and processing of circuit boards, but also to the production and processing of any given workpieces. 
       SUMMARY 
       [0006]    The present invention seeks to solve the problem of developing a device of the type specified above which facilitates precise positioning of the workpiece in relation to a tool, test pin or similar and which, however, can also be used for various applications. 
         [0007]    The problem can be solved by having in the work station at least one reference that can be brought into alignment with the mark. 
         [0008]    In the present case, the workpiece, in particular the circuit board or blank, should preferably be aligned prior to printing or any type of processing. This is accomplished by having at least one mark arranged on the blank/circuit board and by having these marks brought into alignment with a reference. The mark can be, for example, a simple cross, while the reference can be a reference ring. For precise positioning, the cross must be located entirely within the ring. 
         [0009]    In a preferred exemplary embodiment, the reference is arranged in a drill hole in the hold-down plate itself. Located above the hold-down plate is a camera which looks through the drill hold and reference and watches the mark. The camera thus records precisely and without distorting the image showing how the reference is arranged in relation to the mark. If this relationship is incorrect, the position of the circuit board must be adjusted. Within the scope of this invention, it is of course conceivable, albeit more technically involved, that the hold-down plate can be adjusted jointly with the carrier plate for the test pins. 
         [0010]    If the position of the circuit board must be adjusted, then an appropriate control unit activates an adjustment unit according to coordinates input by the camera. This adjustment unit should preferably be able to alter the position of at least the hold-down plate and the carrier plates with the test pins in at least one plane. In this case, the transport mechanism is spatially fixed for the circuit board. However, the opposite arrangement in which namely one unit each from the hold-down plate and the carrier plates with the test pins is in fixed position, while the transport mechanism can be adjusted in a plane is also conceivable. 
         [0011]    In a simple exemplary embodiment, the adjustment element features a base plate mounted in a floating manner which is moved in the X- and Y-direction by means of at least one, however, preferably three eccentric tappets. This movement occurs against the force of opposite lying force accumulators which can be realized as spring-loaded pins, for example. 
         [0012]    For the sake of simplicity, the eccentric tappets themselves are commercially available ball bearings which, however, rest eccentrically on the shaft of a step motor. However, other embodiments are also conceivable here and should fall under the scope of the inventive concept. 
         [0013]    The method according to the invention is characterized above all by the fact that the mark is brought into alignment with the reference. The reference is situated preferably in the hold-down plate. Prior to alignment this is driven as close as possible to the circuit board without touching it, however, such that displacing the transport mechanism does not cause the circuit board to shift on the transport mechanism. Only once the mark and the reference are in alignment, is the hold-down plate lowered and the circuit board held tight and checked. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Additional advantages, features and details of the invention are contained in the following description of preferred exemplary embodiments as well as in the drawing, which illustrates: 
           [0015]      FIG. 1  a schematically illustrated frontal view of a device according to the invention for producing and/or processing circuit boards in a work station; 
           [0016]      FIG. 2  a schematic top view of an adjustment unit according to the invention for the device illustrated in  FIG. 1 ; 
           [0017]      FIG. 3  a top view of a partial area of a transport mechanism for circuit boards in a device as illustrated in  FIG. 1 ; 
           [0018]      FIG. 4  a top view of a hold-down area; 
           [0019]      FIG. 5  a section through the partial area illustrated in  FIG. 3  along line IV-IV; 
           [0020]      FIG. 6  a schematically illustrated top view of a partial area of a circuit board or blank in the work station of the device as illustrated in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    According to  FIG. 1 , a circuit board  1  is to be processed, in this case tested, in a work station  2 . In this exemplary embodiment, this workstation  2  features two carrier plates  18 . 1 ,  18 . 2  arranged one-over-the-other with test pins  17 . 1 ,  17 . 2  arranged thereon, the test pins  17 . 1  and  17 . 2  facing one another. Located therebetween is a hold-down plate  11 . The carrier plates  18 . 1 ,  18 . 2  and the hold-down plate  11  are slidably arranged on guide columns  4 . 1 ,  4 . 2 . The movement thereof along the guide columns  4 . 1 ,  4 . 2  is generated by corresponding drives, only the two drives  19 . 1  and  19 . 2  for carrier plates  18 . 1  and  18 . 2  being shown. 
         [0022]    The drive  19 . 1  is located on a cross bar  21  of a support frame  22 , which in turn rests on an adjustment unit  5  by means of which the entire workstation  2  can be moved relative to the transport mechanism  3  and a base frame  7 . 
         [0023]    The circuit board  1  rests on the transport mechanism  3  of any type which is fixed in relation to the other construction elements (not further illustrated in the drawing) of the device according to the invention, for example on the frame  7 . 
         [0024]    The adjustment unit  5  is provided in this frame  7 . As  FIG. 2  shows, this unit features a plate  6  which is mounted in a floating manner in the frame  7 . This means that the plate  6  can be moved within the frame  7  in the X and Y directions. This is effected by eccentric tappets  8 . 1  through  8 . 3  which, according to an exemplary embodiment, are each comprised of a ball bearing which rests eccentrically on a shaft  9  of a step motor not illustrated in greater detail. Opposite each of the eccentric tappets  8 . 1  through  8 . 3  is a force accumulator  10 . 1  through  10 . 3  which can, for the sake of simplicity, be a helical spring. 
         [0025]    Above the transport mechanism  3  is a hold-down plate  11 , which can be moveable in relation to the circuit board  1  in any desired manner. As  FIGS. 4 and 5  show, it possesses two drill holes  12 . 1  and  12 . 2  in which a reference disc  13  is inserted. Located on this reference disc is a reference, in this case for example a reference ring  14  as shown in  FIG. 6 , with which a mark  15  on the circuit board  1  must be brought into alignment. For each drill hole  12 . 1  and  12 . 2  a dedicated camera  16 . 1  and  16 . 2 , respectively, is assigned, each of which looks through the drill hole  12 . 1 ,  12 . 2  and the reference disc  13  to the mark  15 , as the dashed line indicates. 
         [0026]    The mode of function of the present invention is described below: 
         [0027]    A circuit board  1  with multiple individual blanks in panels, as illustrated in  FIG. 3 , is transported through the workstation  2  by means of the fixed transport mechanism  3 , each aligned with and contacted by the corresponding test pins  17 . 1 ,  17 . 2  on the carrier plates  18 . 1 ,  18 . 2 . This occurs by means of the corresponding drives  19 . 1 ,  19 . 2 . 
         [0028]    However, the circuit board must be aligned before the carrier plates  18 . 1 ,  18 . 2  with the test pins  17 . 1 ,  17 . 2  are lowered onto the circuit board  1  through the corresponding drill holes  20  in the hold-down plate  11 . For this purpose, the hold-down plate  11  is driven directly against the circuit board  1 , but without touching it. The relationship between the reference ring  14  and the mark  15  is observed via the two cameras  16 . 1  and  16 . 2 . If the mark  15  is outside the reference ring  14 , then the work station  2  must be adjusted in relation to the position of the circuit board, which is performed by means of an adjustment unit  5 . The plate  6  and thereby the entire support frame  22  move in both the X- and Y-direction via the eccentric tappets  8 . 1  through  8 . 3  against the force of the force accumulators  10 . 1  through  10 . 3 . 
         [0029]    Afterward, the hold-down plate  11  can be lowered entirely, and the circuit board  1  can fixed between the transport mechanism  3  and the hold-down plate. The drive  19 . 1  now lowers also the carrier plate  18 . 1  with the test pins  17 . 1 , which charge and test the circuit board  1  through the drill holes  20  in the hold-down plate  11 . Extremely precise positioning is thereby enabled. Contact can now be made with the smallest structures. 
         [0030]    As mentioned above, the device according to the invention can be used not only for testing circuit boards, but also for the production thereof, for example. If, for example, circuit boards are produced using the silk screen printing, then the screen can accordingly be aligned over the circuit boards.