Abstract:
An automated steel lamination stacking system for a transformer core. A computer controlled robot arm with a machine vision system locates each of a series of laminations formed by a core former. A hand with a pair of fingers disposed on the end of the robot arm sequentially grasps each of the laminations and transfers each lamination to a forming table which receives and shapes each lamination into a stack to form the desired transformer core. As the empty hand returns to retrieve the next lamination, an extended arm is activated to square the stack. If the preset number of laminations has been stacked and a desired weight has been reached, then the process is complete. Otherwise the stacking process continues. Because the laminations grow in size as the core is built, the stacking system adjusts the position of the fingers to grasp each lamination.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/210,608 filed Mar. 20, 2009, the disclosure of which is incorporated herein by reference in its entirety. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention relates to the manufacture of transformer cores, and in particular, to an automatic system for stacking laminations from a core former. 
         [0005]    2. Brief Description of the Related Art 
         [0006]    A transformer includes a core that is formed from multiple stacked or nested metal laminations. The size and shape of the laminations is determined by the type and size of core. However, even for a particular core, the size and shape of each lamination must vary in order for the laminations to stack or nest together tightly. 
         [0007]    A core former is a machine that accepts information from an operator as to the parameters of the particular transformer core desired. The system receives a roll of sheet metal, determines the dimensions of each individual lamination and automatically forms and cuts a series of laminations that the operator manually stacks to produce the desired core. 
         [0008]    The manual process for operating a core former requires that an operator be present and perform the following actions at each one of several stationary systems: 
         [0009]    (1) Post setup, the operator must ensure that the system is active and find the appropriate core mold (typically an I-beam) matching the dimensions of the inner window of the core to ensure that the produced core maintain its form. 
         [0010]    (2) The operator must place the core mold upon the operator&#39;s workstation, ensure that all proper dimensions are input into the system PC and sent to the core former. Assuming that all parameters are inputted, the system starts feeding steel to begin its forming process. 
         [0011]    (3) As each lamination exits the core forming system, the operator must grab every descending lamination and place it around the core mold, occasionally adjusting the build to ensure that the laminations fit securely. 
         [0012]    (4) Upon completion of the core, the operator must move the core to a scale to ensure that core meets weight tolerances. If so, the operator must then bind the core with mild steel strapping, label the core and move the core to a conveyor for loading. If not, the operator must execute a build-up operation for additional laminations and continuously re-weigh until the core reaches the required weight. 
         [0013]    The limitations of the prior art are overcome by the present invention as described below. 
       BRIEF SUMMARY OF THE INVENTION 
       [0014]    The present invention is a stacking system that operates in conjunction with a transformer core former. The present invention comprises a computer controlled robot arm with a machine vision system to locate each of a series of laminations formed by a core former and a hand and fingers to sequentially grasp each of the laminations and to transfer each lamination to a forming table which receives and shapes each lamination into a stack to form the desired transformer core. As used herein, the term “hand” refers to the entire robot end-of-arm tooling structure and the term “finger” refers to an apparatus located on the hand that procures the laminations with the use of any form of grasping mechanism. “Core” refers to a transformer core produced by stacking a set amount (in weight) of laminations. “Lamination” refers to a strip of core steel of a predetermined length, width, and shape. The term “extended arm” refers to a mechanism to square the most recently stacked lamination. 
         [0015]    The stacking system of the present invention is loaded with the parameters for a particular type and size of transformer core. In particular, the system requires information about the current core, such as the size of the core (or size of beginning lamination) and desired total weight. This information may be obtained automatically from the core former or another type of input may be used. 
         [0016]    When producing a lamination, the core former stops at a preset point before making the final cut that separates the lamination from the sheet metal coil. Once the stacking system has obtained the lamination, the final cut is made and the stacking system moves the lamination toward the stack area. The stacking system places the lamination over the existing stack, closes the fingers to shape the lamination and releases the lamination. As the empty hand returns to retrieve the next lamination, the extended arm is activated to square the stack. If the preset number of laminations has been stacked and the core has reached the desired weight, then the process is complete. Otherwise the stacking process continues. Because the laminations grow in size as the core is built, the stacking system determines if the distance between the fingers needs to be adjusted to grasp each lamination. 
         [0017]    After a preset number of laminations have been stacked, an integrated load cell weighs the core and compares it to a preset value. If the desired core weight is not reached, the stacking system signals the core former to produce extra laminations as needed. 
         [0018]    The present invention requires that an operator be present and perform these actions at only one hub, which may operate multiple systems: 
         [0019]    (1) Ensure that all proper dimensions are input into the system computer processing system, which may include a computer processing system (also referred to herein as a “CPU” or “PC”) associated with the core former and a separate computer processing system associated with the robot arm (referred to herein as a “robot controller”). Each of the CPU and the robot controller includes machine readable storage media on which sets of executable instructions reside. The CPU and robot controller may be connected with a communications link such as an Ethernet connection. Assuming that all parameters are input, the system starts feeding steel to begin its forming process. 
         [0020]    (2) As each lamination (being built to the proper dimensions) exits the core former, the stacking system&#39;s end-of-arm tooling procures the descending laminations using a grasping mechanism and places each one around the preceding laminations, occasionally using an extended arm to adjust the build and ensure that the laminations fit securely. 
         [0021]    (3) Upon completion of the core, a scale built into the workstation ensures that each core meets weight tolerances. If so, an off-loading mechanism moves the completed core to a conveyor for unloading. If not, the stacking system executes a build-up by having the core former produce additional laminations. The system continuously re-weigh on its own until the core reaches the required weight. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0022]    These and other features, objects and advantages of the present invention will become better understood from a consideration of the following detailed description and accompanying drawing where: 
           [0023]      FIGS. 1A-C  comprise a flow chart of the steps carried out by one embodiment of the present invention. 
           [0024]      FIG. 2  is a perspective view of an example of a transformer core former and decoiler machine. 
           [0025]      FIG. 3  is a top plan view of one embodiment of the robot arm and forming table the present invention together with a core former and decoiler machine. 
           [0026]      FIG. 4  is a top plan view of a transformer core comprising a series of laminations. 
           [0027]      FIG. 5  is a block diagram of one embodiment of the present invention showing the interconnections between the computer processing systems, each having a computer readable storage medium on which a set of executable instructions reside for interfacing with and controlling the automatic operation of the various components of the stacking system. 
           [0028]      FIG. 6  is a perspective view of one embodiment of the core former and forming table showing a disposition of laser line projectors with respect to a lamination formed but not yet cut off by the core former. 
           [0029]      FIG. 7  is a perspective view of an embodiment of the robot arm and the tool including the hand and fingers at the end of the robot arm. 
           [0030]      FIG. 8  is a perspective view of an embodiment of the hand and fingers. 
           [0031]      FIG. 9  is a perspective view of the hand and fingers of  FIG. 8  grasping a lamination. 
           [0032]      FIG. 10  is a top plan view of an embodiment of the forming table. 
           [0033]      FIG. 11  is a cross sectional side elevation view of an embodiment of the forming post. 
           [0034]      FIG. 12  is a perspective view of an embodiment of the base of the forming table. 
           [0035]      FIG. 13  is a perspective view of an embodiment of the forming table. 
           [0036]      FIG. 14  is a top plan view of a partially formed transformer core showing a lamination loosely stacked onto the partially formed core. 
           [0037]      FIG. 15  is a perspective view of the forming table of  FIG. 10  showing an embodiment of the shapers. 
           [0038]      FIG. 16A  is a perspective view of one of the shapers of  FIG. 15  showing the shaper in a first position in which it is disposed horizontally below the common plane of the forming table. 
           [0039]      FIG. 16B  is a perspective view of the shaper of  FIG. 16A  showing a second position in which it is disposed vertically in contact with the side of a lamination. 
           [0040]      FIG. 16C  is a perspective view of the shaper of  FIG. 16B  after it has been translated horizontally against the side of the lamination. 
           [0041]      FIG. 17  is a perspective view of an embodiment of a shaper cam. This view is of a left shaper cam, that is, the shaper cam associated with the left carriage. 
           [0042]      FIG. 18A  is an partial cross sectional view of the shaper cam of  FIG. 16C  along the line  18 A- 18 A with a shaper having rollers disposed in channels to impart stability to the shaper. 
           [0043]      FIG. 18B  is a partial cross section of the shaper cam of  FIG. 18A  along the lines  18 B- 18 B. 
           [0044]      FIG. 18C  is a partial elevation view of the shaper cam of  FIG. 17 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0045]    With reference to  FIGS. 1-18C , the preferred embodiments of the present invention may be described as follows: 
         [0046]    The present invention is a automated lamination stacking system that operates in conjunction with a transformer core former. With reference to  FIGS. 2 and 4 , a transformer core former  30  accepts information from an operator as to the parameters of a desired transformer core  35  (such as the dimensions of the window  34  in the center of the transformer core  35  and the desired final weight), receives a roll of sheet metal  31  (for example, from a decoiler machine  32 ), determines the dimensions of each of a series of laminations  33  and automatically forms and cuts a series of formed laminations  33  that may be stacked to produce the desired transformer core  35 . As can readily be seen, each individual formed lamination  33  is formed with individually specific dimensions that allow it to be wrapped around each preceding lamination so as to form a tightly nested series of laminations. As used herein, the term “stack” refers to a partially formed core comprising a series of tightly nested laminations. The term “stack” is used interchangeably with the term “partially formed core.” Examples of a transformer core former and decoiler machine are the AEM Unicore UCM3000 and UDM4000 made by AEM Cores Pty. Ltd., Gillman, Australia. 
         [0047]    As shown in  FIG. 3 , the present invention comprises a computer controlled multi-axis robot arm  10 , a machine vision system to locate each of a series of laminations formed by the core former  30  and a hand and fingers combination located at an end of the robot arm  10  to sequentially grasp each of the series of laminations and to transfer each lamination to a forming table  11  which receives and shapes each lamination into the stack until the desired transformer core is formed. The M-10iA™ six-axis industrial robot (FANUC Robotics America, Inc., Rochester Hill, Mich.) has been found to be suitable for the practice of the present invention. A robot controller  140  is associated with the robot arm  10  which controls the operation of the robot arm  10  and other portions of the system as described following. 
         [0048]    The core former  30  forms a series of laminations  33  that together form the desired transformer core. The laminations are formed from a roll of metal  31 . Each lamination  33  is formed with a number of creases corresponding to the corners of each lamination as it is stacked around the previous laminations to form the transformer core. Although not so limited, the operation of the system will be described with respect to one embodiment in which the creases define five segments of the lamination  33 —the back  36  of the lamination  33 , the two sides  37  of the lamination  33 , a long segment  38  of the front of the lamination  33  and a short segment  39  of the front of the lamination  33 . The long segment  38  and the short segment  39  when nested together meet to form the front  40  of the lamination  33 . The lengths of each of the five segments  36 ,  37 ,  38 ,  39  are continuously adjusted by the core former  30  so that each lamination  33  is formed with the correct dimensions to nest securely around each previous lamination. After shaping the lamination  33  to produce the creases at the appropriate locations, the final action of the core former  30  is to cut each lamination  33  free from the metal roll  31 . The core former  30  carries out these actions automatically after being provided with the desired core sizes by the operator  41 . 
         [0049]    The core former  30  is operated by a set of executable software instructions residing on computer readable media associated with the core former  30 . Such software will necessarily be modified to interface with the executable software instructions that operate the stacking system of the present invention. The software instructions for the stacking system of the present invention comprise a set of executable instructions residing on computer readable storage media associated with the computer processing system CPU  50  and interfaced with and controlling the automatic operation of the core former  30 . The CPU  50  also receives information from load cells  87  and camera  64  as described herein. CPU  50  interfaces with a separate computer processing system referred to herein as a robot controller  140 . Robot controller controls the operation of robot arm  10 , hand  70 , fingers  71 ,  72 , shapers or wipers  91 , and conveyors  96 . Robot controller  140  received information from vacuum sensors  90 . Robot controller  140  and CPU  50  are interfaced by means of a communications link  141  such as an Ethernet connection.  FIG. 5  is a block diagram showing the interconnections between the CPU  50 , robot controller  140  and the various components of the stacking system. 
         [0050]    As the core former  30  produces each lamination  33 , it stops before making the final cut. The lamination  33  hangs vertically from the core former  30  with the creases  62  in the lamination  30  oriented substantially horizontally. For a particular example of a core former  30 , some structural modification may be required to allow the lamination  33  to hang vertically. 
         [0051]    As shown in  FIG. 6 , one or more laser line projectors  60  are oriented toward the core former  30  at a right angle to the lamination  33  so as to place a vertical laser reference line  61  along the lamination  33 . Depending on the placement of the laser line projectors  60 , only a single projector  60  may be necessary to place the vertical laser reference line  61  along substantially the full length of the lamination  33 . However, if a single laser line projector  60  cannot place a substantially full length laser line  61  due, for example, to the lamination  33  itself blocking the line of sight of the laser line projector  60 , then more than one projector  60  may be employed to obtain a substantially full length laser reference line  61 . As shown in  FIG. 6 , the laser line projectors  60  may be mounted on the core former  30  or the forming table  11 . 
         [0052]    From a head-on perspective, the reference line  61  appears straight, but due to creases  62  formed in the lamination  33  by the core former  30 , from an angle to the side of the centerline of the core former  30 , the vertical laser reference line  61  has a series of peaks  63  corresponding to the creases  62  in the lamination  33 . A camera  64  located off the centerline of the core former  30  is able to visualize the peaks  63  in the laser reference line  61 . This information is transmitted and interpreted by a machine vision system which calculates where the creases  62  are located in space with respect to a coordinate system based on the face plane of the core former  30 . The machine vision system includes a set of executable instructions residing on the computer readable storage medium within the computer processing system (CPU)  50 . The executable instructions residing on the robot controller  140  translate the coordinate system into robot coordinates based on the 6-axis robot arm  10  through training the finger positions and then calibrating the machine vision camera  64  with the robot arm  10 . The system thus is able to direct the robot arm  10  to a position where it can grasp the laminations  33  securely as described following. At higher speeds of operation, it is possible that the lamination  33  may tend to move for a period of time following its production from the core former  30 . In this situation, the machine vision system may have difficulty in capturing the position of the lamination  33 . In one embodiment, an electromagnet (not shown) may be placed on the core former  30  alongside the exit area of the lamination  33 . The electromagnet may be activated just before the core former  30  guillotine releases the lamination  33  thus stabilizing the position of the lamination  33  and allowing the laser  60  and camera  64  to capture the image faster and more accurately. 
         [0053]    The laminations  33  are grasped by a tool at the end of the robot arm  10 . As shown in  FIG. 7 , the tool comprises a hand  70  and fingers  71 ,  72 . The robot arm  10  operates in two coordinate systems—one based on the core former  30  and the other based on the forming table  11 . The location of the origin on the forming table  11  is “learned” by the robot arm  10  with the aid of an operator  41 . 
         [0054]    As shown in  FIGS. 8 and 9 , the hand  70  comprises an upper finger  72  and a lower finger  71 . 
         [0055]    As shown in  FIG. 9 , the upper finger  72  grasps the lamination  33  at an upper point  73  on one side of the lamination  33  near the crease between one side  37  and the back  36 . The lower finger  71  grasps the lamination  33  at a corresponding lower point  74  on the opposite side of the lamination  33  near the crease between the opposite side  37  and the back  36 . As each lamination  33  increases in size over the previous lamination, the vertical distance between the upper finger  72  and the lower finger  71  also increases so that the laminations  33  are grasped at the same locations despite the increase in length of the back  36  of each lamination  33 . Grasping each lamination  33  at these points aids in forming the lamination  33  around the core  35  as described below. In one embodiment, the upper finger  72  is mechanically adjustable to either of two locations. The lower finger  71  is also mechanically adjustable to any one of three locations. The adjustments enable the distance between the fingers  71 ,  72  to be set for various sizes of cores  35  and laminations  33 . In addition, either the lower finger  71  or the upper finger  72  is disposed on a linear actuator comprising a screw  75  driven by an auxiliary axis controlled by the robot controller  140  so that that the distance between the upper finger  72  and the lower finger  71  can be adjusted automatically from one lamination  33  to the next to accommodate for growth in the size of each lamination  33  throughout a core  35 . In one embodiment, a change in size of up to 290 mm (11.4 inches) can be accommodated throughout the production of a core  35 . 
         [0056]    In one embodiment each of the fingers  71 ,  72  comprise a pair of vacuum cups  76  spaced apart horizontally on a gripper  77 . The vacuum cups  76  should be suitable for use on oily metal surfaces. BFF-P Suction Cups (PIAB, Hingham, Mass.) have been found to be suitable for use in the practice of the present invention. The gripper  77  is mounted to the hand  70  by means of a bearing (not shown) that allows the gripper  77  to rotate to a limited degree. This rotation allows the gripper  77  to accommodate itself to some movement of the lamination  33  during the grasping process. A pair of vacuum cups  76  on each finger  71 ,  72  is desirable for stability in grasping the lamination  33 . Each of the vacuum cups  76  is also provided with a vacuum sensor  90  so that the system is able to determine that the vacuum cups  76  have securely grasped the lamination  33 . 
         [0057]    In operation, the core former  30  produces a lamination  33  and then pauses before cutting the lamination  33  free from the roll of metal  31 . Based on location information derived from the machine vision system—the laser line projector  60 , the camera  64  and the set of executable instructions residing on the computer readable storage medium within the CPU  50 —the lower finger  71  first contacts and grasps the lower point  74  on the lamination  33 . The lower point  74  is grasped first since the lower end of the lamination  33  is free to move and thus is more susceptible to an alteration in the position of the point at which the lower finger  71  is directed to grasp the lamination  33 . If the upper point  73  were grasped first, it is likely that the point toward which the lower finger  71  is directed would be moved by the act of grasping the upper point  73 . The upper portion of the lamination  33  is more stable since it has not at this point in time been cut from the roll of metal  31  to which it remains attached. After the lower finger  71  has securely grasped the lamination  33  at the lower point  74 , the upper finger  72  is rotated and translated so as to contact and grasp the lamination  33  at the upper point  73  while the lower finger  71  maintains its grip on the lamination  33  at the lower point  74 . 
         [0058]    The fingers  71 ,  72  are mounted on brackets  78  for rotation about pivots  79  toward each other. The rotation is produced by effectors such as pneumatic cylinders  80 . Rotation of the fingers  71 ,  72  toward each other allow for the lamination  33  to be shaped about the stack of previously stacked laminations as described below. 
         [0059]    Once both the upper finger  72  and the lower finger  71  have securely grasped the lamination  33  at the upper and lower points  73 ,  74 , respectively, the final cut is made by the core former  30  freeing the lamination  33  from the roll of metal  31 . The robot arm  10  then moves the lamination  33  from a position in which it is hanging vertically from the core former  30  to a position horizontally disposed above the forming table  11 . 
         [0060]    With reference to  FIGS. 10-13 , the forming table  11  is provided with four supporting surfaces  101 ,  102 ,  103 ,  104 . Supporting surfaces  101 ,  104  are disposed on a left carriage  105 , while supporting surfaces  102 ,  103  are disposed on a right carriage  106 . The carriages  105 ,  106  are preferably an open framework supported and moving on slides, linear bearings or the like. The particular mechanisms to support and allow movement of the carriages  105 ,  106  are not critical to the present invention and may be any of various mechanisms well known to those of ordinary skill in the art. The faces of the supporting surfaces  101 ,  102 ,  103 ,  104  are disposed in a common plane  82  (also referred to herein as the surface of the forming table). Each supporting surface  101 ,  102 ,  103 ,  104  is provided with a forming post  81  extending vertically from the common plane  82 . The four posts  81  are retractable into a respective cylinder  107  by effectors (not shown), such as pneumatic cylinders, solenoids and the like, so that in the fully retracted position they are disposed below the common plane  82  of the respective supporting surfaces  101 ,  102 ,  103 ,  104 . The distances between the four forming posts  81  are adjustable, either manually or automatically, to accommodate the size of the window  34  of the transformer core  35  that is being formed. The distance between the pair of posts  81  disposed on left carriage  105  and the pair of posts  81  disposed on right carriage  106  may be adjustable, e.g. by a single manually operated screw mechanism  83 . The distance between the pair of posts  81  disposed on supporting surfaces  101 ,  104  and the distance between the pair of posts  81  disposed on supporting surfaces  102 ,  103  may also be adjustable. In one embodiment the distances may be individually adjustable, e.g., each by a separate manually operated screw mechanism  84 , or may be adjusted by the same mechanism so that the distances are always the same. Even if the distances between the each pair of posts are separately adjustable, in practice the distances will normally be the same. The carriages  105 ,  106  must be open at least in the vicinity of the forming posts  81  to allow movement of the forming posts  81  as described hereinafter. 
         [0061]    The forming table  11  (also referred to herein as a “build table”) may be mounted on a base  85  having a plurality of legs  86 . A load cell  87  is disposed beneath the lower end of each leg  86 . Information from the load cells is transmitted to the CPU  50  to allow the calculation of the weight of a stack of laminations  33 . 
         [0062]    With the distances between the forming posts  81  set and the forming posts extended above the common plane  82  of the forming table  11 , the robot arm  10 , by appropriate rotation and translation, places the lamination  33  about the forming posts  81 . The fingers  71 ,  72  are mounted for rotation toward each other to form the lamination  33  loosely around the forming posts  81  in a position that approximates the desired position of the lamination  33  on the stack of previously stacked laminations that constitute the partially formed core  35  as shown in  FIG. 14 . It is desirable that the finger  71 ,  72  nearest to the short front side  39  moves toward the other finger first and then the finger  71 ,  72  nearest to the long front side  38  moves toward the other finger next. This sequence of actions produces the tightest stack. The two sides  37  are brought into near contact with the sides of the previously placed lamination so that the lamination  33 , that was originally more nearly linearly extended as it exited the core former  30  is more nearly box shaped as the fingers  71 ,  72  form it about the partially formed core  35 . 
         [0063]    As shown in  FIGS. 10 and 15 , the forming table  11  also comprises an extended arm which, in the preferred embodiment, comprises a pair of shapers  91  (also referred to herein as “wipers”), one disposed on left carriage  105  and one disposed on right carriage  106  so a shaper  91  is disposed toward each side of the partially formed transformer core  35 . The shapers  91  are actuated by effectors (not shown), such as pneumatic cylinders, solenoids or the like, so that they may be disposed below the common plane  82  of the forming table  11  to avoid interfering with the placement of the lamination  33  by the robot arm  10  about the partially formed core  35 . As shown in  FIGS. 16A-C , once the lamination  33  (shown in phantom outline) has been placed about the partially formed core  35  and the robot arm  10  retracted, the shapers  91  are moved by the pneumatic cylinders in a first motion that rotates the shapers  91  from a horizontal position below the common plane  82  as shown in  FIG. 16A  into a vertical position and then in a second motion that translates the shapers  91  horizontally into contact with the sides  37  of the lamination  33  as shown in  FIG. 16B . With reference to  FIGS. 15-18C , the motion of the shaper  91  is determined by rollers  110 ,  130  attached to the shaper  91  that follow a J-shaped channel  111  in shaper cam  120 . (Shaper cam  120  is the shaper cam associated with the left carriage  105 ; the shaper cam associated with the right carriage  106  is a mirror image of the left shaper cam  120 .) The J-shaped channel  110  comprises a circular section  113  and a straight section  112 . The initial motion that brings the shaper  91  from a horizontal position to a vertical is determined by the circular section  113 . After the shaper is in the vertical position, the second motion horizontally into contact with the lamination  33  is determined by the straight section  112 . 
         [0064]    The shapers  91  are desirably provided with a degree of resilient compliance to ensure firm contact between the inner faces  92  of the shapers  91  and the sides  37  of the lamination  33 . However, to avoid excessive compliance the shapers  91  also have a roller  93  as shown in  FIGS. 18A  and B that enters a horizontal channel  94  upon rotation of the shapers  91  into a vertical position. The horizontal channel  94  provides stability to the shaper  91  and ensures that it is supported into contact with the sides  37  of the lamination  33  as it is translated from the first vertical position to the position shown in  FIG. 16B  where the inner face  92  of the shaper  91  is in contact with the sides  37  of the lamination  33 . Once the shapers  91  have contacted the sides  37  of the lamination  33 , the shapers  91  (which together with the respective shaper cams are mounted for sliding motion along the sides of the lamination) are then moved laterally by pneumatic cylinders  95  so as to slide along the sides  37  of the lamination  33  and thereby pull the lamination  33  into snug contact with the partially formed core  35 . The faces  92  of the shapers  91  must provide sufficient sliding friction to move the sides  37  of the laminations  33  into snug alignment with the partially formed core  35  but without excessive friction that would prevent the faces  92  of the shapers  91  from sliding along the sides  37  of the laminations  33 . Acetal plastic has been found to provide the requisite coefficient of sliding friction. After forming the lamination  33 , the shapers  91  are retracted to their first position below the surface  82  of the forming table  11  as shown in  FIG. 16A . 
         [0065]    Once the lamination  33  has been snugly formed around the partially formed core  35 , the core  35  is weighed. As noted above, the forming table  11  is mounted on a base  85  that is disposed on a series of load cells  87  that perform the weighing function. If the partially formed core  35  is found to weigh less than the desired weight, a signal is sent by the CPU  50  to the core former  30  to form the next lamination  33 . The process is then repeated until a sufficient number of laminations  33  have been added to the core  35  to reach the desired weight. At this point, the forming posts  81  are retracted to a position below the common plane  82  of the forming table  11 . The completed transformer core  35  rests on a pair of conveyors, such as chain conveyors  96 , that are positioned slightly above the common plane  82  of the forming table  11  as shown in  FIG. 13 . The conveyors  96  are activated to move the formed core  35  off the forming table  11  onto an output conveyor  97  that conveys the core  35  to further processing stations. In addition to the pair of conveyors  96 , the forming table  11  also includes a central rib  98  disposed between the pair of conveyors  96  to support the center of the core  35 . The rib  98  is provided with a low friction surface disposed slightly below the tops of the pair of conveyors  96  so that the center of the formed core  35  is supported but nevertheless is allowed to slide off the forming table  11  when the pair of conveyors  96  are activated. The rib  98  may also be spring loaded so that its top surface is always disposed so that the pair of conveyors  96  bear most of the weight of the formed core  35  and therefore are able to move the formed core  35  off the forming table  11 . 
         [0066]    As outlined in the flow chart of  FIGS. 1A-C , the operation of the system begins as shown in block  200  with confirming that the core former  30  and the robot arm  10  have power and booting the PC or CPU  50 . The posts  81  are set as shown in block  201  to the desired dimensions of the window  34  of the transformer core  35  that is to be produced. The parameters of the desired transformer core  35 , including dimensions, desired number of laminations and weight of the core  35  are input as shown in block  202  into the software consisting of the executable instructions residing on the computer processing system  50  and the robot controller  140 . Operation of the core former  30  is begun as shown in block  203  and a lamination  33  is produced. The laser line projectors  60  project a reference line  61  as shown in block  204  on the lamination  33  produced by the core former  30 . As shown in block  205 , the camera  64  visualizes the line  61  and transmits this information to the executable instructions residing on the CPU  50  to determine the location of the lamination  33  and to instruct the robot arm  10  where to locate the lamination  33 . The hand  70  and fingers  71 ,  72  of the robot arm  10  acquire the lamination  33  as shown in block  206  and move it as shown in block  207  to the forming table  11  where the lamination  33  is placed around the partially formed core  35  comprising the laminations previously stacked on the forming table  11  as shown in block  208 . The fingers  71 ,  72  are closed as shown in block  209  to begin the process of shaping the lamination  33  around the partially formed core. As shown in block  210 , the hand  70  then releases the lamination  33 . The extended arm comprising the pair of shapers  91  is then activated as shown in block  211  to complete the process of shaping the lamination  33  around the partially formed core  35 . If the preset number of laminations  33  has not been reached as shown in block  212 , the fingers  71 ,  72  are indexed as shown in block  213  as necessary to acquire the next lamination formed by the core former  30 . If the present number of laminations has been reached, a determination is then made from the reading provided by the load cells  87  if the preset core weight has been reached as shown in block  214 . If so, the core  35  is completed as shown in block  215  and it is moved off the forming table  11  and onto the output conveyor  97  for further processing. If the preset core weight has not been reached, then the core former  30  is signaled to produce another lamination as shown in block  216  and the cycle proceeds until all preset parameters are satisfied. 
         [0067]    The present invention has been described with reference to certain preferred and alternative embodiments that are intended to be exemplary only and not limiting to the full scope of the present invention as set forth in the appended claims.