Patent Publication Number: US-2006000086-A1

Title: Electronic component mounting apparatus and electronic component mounting method

Description:
CROSS-REFERENCE OF THE INVENTION  
      This invention is based on Japanese Patent Application No. 2004-176742, the content of which is incorporated by reference in its entirety.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to an electronic component mounting apparatus and an electronic component mounting method where an electronic component is mounted on a printed board after a board recognition camera takes an image of a positioning mark on the printed board and a recognition processing device recognizes the image taken by the board recognition camera.  
      2. Description of the Related Art  
      This kind of electronic component mounting apparatus has been known through the Japanese Patent Application Publication No. 2003-318600 and so on. In this electronic component mounting apparatus, electronic components are mounted on the printed board after the position of the printed board already positioned is recognized by the board recognition camera. After all the electronic components are mounted on the printed board, the printed board is discharged to a downstream device.  
      However, when the printed board is unstably positioned due to a mistakenly replaced positioning member for positioning the printed board or positioned being warped (e.g. warped upward), since the electronic component is mounted on the unstable printed board or mounted on the warped printed board which is supposed to be straight, the position where the electronic component is mounted can be shifted from a proper position on the printed board. These occur because the electronic component is mounted thereon after the position of the printed board is recognized.  
     SUMMARY OF THE INVENTION  
      The invention provides an electronic component mounting apparatus that includes a board recognition camera taking an image of a positioning mark on a printed board, a recognition processing device determining a position of the positioning mark based on the image of the positioning mark taken by the board recognition camera, a mounting unit mounting an electronic component on the printed board based on the position of the positioning mark determined by the recognition processing device, and a control device that makes the board recognition camera take a first image of the positioning mark before any electric component is mounted on the printed board and take a second image of the positioning mark after an electronic component is mounted on the printed board, makes the recognition processing device determine a first position of the positioning mark based on the first image and determine a second position of the positioning mark based on the second image, compares the first and second positions, and stops mounting the electronic component when a difference between the first and second positions is out of a predetermined allowable range. The control device may inform an operator of the difference between the first and second positions, rather than stopping the operation.  
      The invention also provides a method of mounting an electronic component. The method includes providing a printed board having a positioning mark, taking a first image of the positioning mark before any electric component is mounted on the printed board, determining a first position of the positioning mark based on the first image, taking a second image of the positioning mark after an electronic component is mounted on the printed board, determining a second position of the positioning mark based on the second image, comparing the first and second positions, and stopping a mounting operation of the electronic component when a difference between the first and second positions is out of a predetermined allowable range. An operator may be informed of the difference, rather then the operation being stopped. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a plan view of an electronic component mounting apparatus of the invention.  
       FIG. 2  is a plan view of a conveying chute of the invention.  
       FIG. 3  is a left side view of the conveying chute and an XY table of the invention.  
       FIG. 4 . is a side view of the fixed conveying chute seen from an arrow X of  FIG. 2 .  
       FIG. 5  is a side view of the fixed conveying chute being on standby seen from the arrow X of  FIG. 2 .  
       FIG. 6  is a side view of the movable conveying chute being on standby seen from an arrow Y of  FIG. 2 .  
       FIG. 7  is a side view of the fixed conveying chute seen from the arrow X of  FIG. 2 .  
       FIG. 8  is a left side view of the conveying chute and the XY table of the invention.  
       FIG. 9  is a side view of the fixed conveying chute in a state that a printed board lies thereon and a cylinder is operated, seen from the arrow X of  FIG. 2 .  
       FIG. 10  is a side view of the movable conveying chute in a state that the printed board lies thereon and the cylinder is operated, seen from the arrow Y of  FIG. 2 .  
       FIG. 11  is a side view of the fixed conveying chute in a state that no printed board lies thereon and the cylinder is operated, seen from the arrow X of  FIG. 2 .  
       FIG. 12  is a side view of the movable conveying chute in a state that no printed board lies thereon and the cylinder is operated, seen from the arrow Y of  FIG. 2 .  
       FIG. 13  is a view showing a relationship between a light shield board, a sensor attachment body, and a detection sensor.  
       FIG. 14  is a control block diagram.  
       FIG. 15  is a view of a screen of a monitor for setting a board re-recognition-check-stop function.  
       FIG. 16  is a view of the monitor when an electronic component is judged defective. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      An embodiment of an electronic component mounting apparatus for mounting a chip-type electronic component on a printed board of the invention will be described in detail with reference to drawings hereafter. A numeral  1  designates a Y table moving in a Y direction by rotation of a Y axis drive motor  2 , and a numeral  3  designates a XY table moving in X and Y directions by moving in the X direction on the Y table  1  by rotation of a X axis drive motor  4 , where a printed board  6  to be mounted with a chip-type electronic component  5  (hereafter, called “chip component” or “component”) is set by being fixed to a pair of conveying chutes  31  and  32  by a fixing device (not shown).  
      A numeral  7  designates a feeding stage which is provided with many component feeding units  8  for feeding the chip components  5 . A numeral  9  designates a feeding stage drive motor which rotates a ball screw  10  to move the feeding stage  7  in the X direction along linear guides  12  through a nut (not shown) engaged with the ball screw  10  and fixed to the feeding stage  7 .  
      A numeral  13  designates a rotary table intermittently rotating itself. On an outer circumference of the table  13 , mounting heads  15  having a plurality of suction nozzles (not shown) are provided at predetermined intervals corresponding to intermittent pitches.  
      A position where the mounting head  15  stops for picking up the component  5  by suction  30  from the component feeding unit  8  by its suction nozzle (a position of 12 o&#39;clock in  FIG. 1 ) is a pickup station. At the pickup station, the suction nozzle picks up the component  5  by suction.  
      A position where the mounting head  15  stops previous to the pickup position, is a pickup correction station where a pickup correction device  11  corrects a position of the suction nozzle in a Y direction which is a direction of directly going to the moved feeding stage  7 .  
      A position where the mounting head  15  stops next to the pickup position, is a rotation returning position, where a rotation returning device  14  returns the suction nozzle, of which the position is corrected at the pickup correction station so as to pick up the center of the component  5  by suction, to an original position.  
      A numeral  16  designates a component recognition camera that takes an image of a bottom surface of the component  5  held by suction by the suction nozzle. A position where the mounting head  15  stops above the component recognition camera  16  while the rotary table  13  rotates is a recognition station.  
      A position where the mounting head  15  stops next to the recognition station is a angle correction station, where a positional shift of the component  5  held by suction by the suction nozzle is corrected in an rotation angle by rotating the mounting head  15  in a θ direction by a head rotation device  17  having a θ axis drive motor  17 A based on a recognition result of the image taken by the component recognition camera  16 .  
      A second stop position from the angle correction station, is a mounting station, where the component  5  held by suction by the suction nozzle is mounted on the printed board  6 .  
      In FIGS.  2  to  5 , numerals  31  and  32  designate a pair of conveying chutes supported by chute supporting members (not shown). In each of the conveying chutes  31  and  32 , a conveying belt  35  is stretched between sprockets  34  (only one sprocket is shown) provided at least in left and right end portions. The sprockets  34  are rotated by drive sources, so that the conveying belts  35  convey the printed board  6  of which left and right ends are set on the conveying belts  35 . Numerals  38  designate pressing members provided in the movable conveying chute  32  at predetermined intervals, which press the printed board  6  to the fixed conveying chute  31 .  
      The XY table  3  is disposed below the printed board  6 , and movable in the X and Y directions by the X axis drive motor  4  and the Y axis drive motor  2  on a horizontal plane. A front surface of the XY table  3 , which faces the printed board  6 , is provided with a plurality of holes (not shown). Backup pins  37  for supporting the printed board  6  horizontally by being in contact with a back surface of the printed board  6  are provided on the XY table  3  by being inserted in the holes appropriate for forming the size of the printed board  6 , being pullable from the holes.  
      As shown in the Japanese utility model application publication No. hei 6-52197, chute vertical movement levers each having a roller in its end are rotatably set in bearings fixed to the XY table  3 , although not shown. By vertically moving the rollers of the chute vertical movement levers by cylinders, the printed board  6  supported by the conveying chutes  31  and  32  are vertically moved together with the chute supporting members. The chute supporting members vertically move, being guided by guide shafts penetrating the XY table  3 .  
      A supply conveyer having a belt moved by a drive motor is provided on an upstream side of the XY table  3 , and a discharge conveyer having a belt moved by a drive motor is provided on a downstream side of the XY table  3 . With the board conveying chutes  31  and  32  raised, the printed board  6  on the supply conveyer is shifted onto the XY table  3 , and the printed board  6  on the XY table  3  is shifted onto the discharge conveyer.  
      Next, a positioning device  40  for the printed board  6  will be described with reference to  FIG. 4 . The positioning device  40  includes a pair of positioning pins  41  and  42  provided on the XY table  3 . The positioning pin  41  is fixed to the XY table  3 , and can be in contact with a rear end of the printed board  6  in a conveying direction. The positioning pin  42  is fixed to the XY table  3 , being rotatable around a supporting axis  43  as a fulcrum and movable so as to have a space between the pins  41  and  42  corresponding to a transverse size of the printed board  6 . When rotated, the positioning pin  42  becomes in contact with a front end of the printed board  6  in the conveying direction.  
      In detail, when the board conveying chutes  31  and  32  descend, the positioning pin  42  is rotated by a drive source (not shown), and holds the printed board  6  with the positioning pin  41 , pressing the board  6  to the positioning pin  41 , so that the printed board  6  is positioned.  
      A numeral  44  shown in  FIG. 6  designates a detection device for detecting presence or absence of the printed board  6 , which is provided in each of the conveying chutes  31  and  32 . The detection device  44  will be described in detail below. A numeral  45  designates a detection lever of which one end is supported by a chute body  46 , being rotatable around a support axis  47 . The detection lever  45  is being pressed upward by fastening an end of a coil spring  48 , which is wound around the supporting axis  47 , to a fixing member  49  fixed to the supporting axis  47  and by fastening another end of this spring  48  to the chute body  46 . Upward rotation of the detection lever  45  is regulated by an operation lever  52  fixed to the supporting axis  47 , the operation lever  52  being in contact with an extended rod  51  of a cylinder  50 .  
      When the cylinder  50  is operated, the rod  51  is drawn in the cylinder  50 , so that the detection lever  45  rotates upward by the coil spring  48 . The detection lever  45  then becomes in contact with the regulation pin  53 , and its upper end level is regulated in a position slightly higher than a guide surface of an upper board of the conveying chute (a lower surface of a block portion  55 ). However, in a case that the printed board  6  lies on the conveying belt  35  when the detection lever  45  rotates upward by the operation of the cylinder  50 , upper portions of the detection levers  45  on the other side push the printed board  6  upward and press it to the block portions  55  formed in the conveying chutes  31  and  32 , so that the printed board  6  can be positioned in a vertical direction.  
      Furthermore, a light shield board  56  is provided in a lower portion of the detection lever  45  on the other side, and a sensor attachment body  57  formed in a U-shape in its cross-section is provided in the chute body  46 , where an emissive element  58 A is provided on one of attachment boards facing each other of the sensor attachment body  57  and a light receiving element  58 B is provided on another one of the attachment boards ( FIG. 13 ), forming a detection sensor  58 .  
      That is, in a case that the printed board  6  is positioned in the vertical direction by pushing and pressing the board  6  to the block portions  55  from downward by the upper portions of the detection levers  45  on the other side when the detection levers  45  are rotated upward by the operation of the cylinders  50 , the light shield boards  56  do not lie in upper bound positions, so that the light receiving elements  58 B receive light from the emissive elements  58 A and the detection sensors  58  recognize the printed board&#39;s presence. On the other hand, in a case that the printed board  6  is slipped from the conveying chutes  31  and  32  or partially defective when positioned, at least one of the detection levers  45  provided in the chutes  31  and  32  rotates upward until it becomes in contact with the regulation pin  53 . Therefore, light from the emissive element  58 A is shielded by the light shield board  56  in the upper bound position and the receiving element  58 B does not receive light from the emissive element  58 A, so that the detection sensor  58  recognizes the printed board  6  as absence.  
      In a mounting operation, in a state that the backup pins  37  become in contact with the back surface of the printed board  6  by descending the conveying chutes  31  and  32  and the printed board  6  is pressed toward the block portions  55  from downward by the upper end portions of the detection levers  45  rotated, the component suction nozzle as a mounting device holding the component  5  supplied from the component feeding unit  8  descends to a predetermined position on the printed board  6  while the printed board  6  is moved in the horizontal direction by the XY table  3 , and mounts the component  5  on the printed board  6 .  
      Next, description will be made based on a control block diagram of  FIG. 14 . The electronic component mounting apparatus includes a CPU  61  serving as a control portion controlling a component mounting operation of the apparatus, and a RAM (random access memory)  62  and a ROM (read only memory)  63  as memories.  
      The RAM  62  is stored with mounting data for each of types of the printed board  6 , which includes information about X and Y directions on the printed board  6  and an angle in mounting order (in order of step number), and alignment numbers of the component feeding units  8 . Furthermore, the RAM  62  is stored with information on types of the chip components (component ID) corresponding to the alignment numbers (lane numbers) of the component feeding units  8 , that is, the component alignment information, and component library data on features of the chip components for each of the component IDs.  
      Then, the CPU  61  controls the component mounting operation of the electronic component mounting apparatus based on data stored in the RAM  62  and according to a program stored in the ROM  63 . That is, the CPU  61  controls driving of the X axis drive motor  4 , the Y axis drive motor  2 , and the e axis drive motor  17 A, respectively through a drive circuit  65 , a drive circuit  66 , and a drive circuit  67 .  
      A numeral  68  designates a recognition processing device connected with the CPU  61  through an interface  64 . The recognition processing device  68  performs a recognition process to images taken and stored by the component recognition camera  16 , and sends a recognition result to the CPU  61 . That is, the CPU  61  outputs a command to perform the recognition process (e.g. calculation of a shifting amount of an electronic component from a proper position) to the image taken and stored by the component recognition camera  16  to the recognition processing device  68 , and receives a recognition result from the recognition processing device  68 .  
      A numeral  70  designates a board recognition camera that takes an image of positions of positioning marks M provided on the printed board  6 . The recognition processing device  68  recognizes the image taken and thus the position of the printed board  6 . That is, the recognition processing device  68  recognizes the image taken and stored by the board recognition camera  70 , and sends a recognition result to the CPU  61 . That is, the CPU  61  outputs a command to perform the recognition process (e.g. calculating a shifted amount from a proper position) to the image taken by the board recognition camera  70  to the recognition processing device  68 , and receives a recognition result from the recognition processing device  68 .  
      In detail, when the recognition processing device  68  recognizes the shifting amounts of the printed board  6  and the chip component  5  held by the suction nozzle from proper positions, the recognition result is sent to the CPU  61 . The CPU  61  moves the XY table  3  in the X and Y directions by driving the X axis drive motor  4  and the Y axis drive motor  2 , and rotates the mounting head  15  (suction nozzle) by a θ angle by driving the θ axis drive motor  17 A, thereby completing correction in the X and Y directions and in the rotating angle around a vertical axis.  
      A monitor (CRT)  71  displays the images that are taken by the component recognition camera  16  and the board recognition camera  70  and stored in the recognition processing device  68 . Various touch panels  72  are provided on the monitor  71 , as an input device for setting data. An operator can perform various settings by operating the touch panel switches  72 . A keyboard can be also used as the input device for setting data, instead.  
      Hereafter, a setting operation of a board re-recognition-check-stop function will be described. On a monitor  71  displaying a screen shown in  FIG. 15 , selection is made on whether or not a board re-recognition-check-stop function is to be used, first. That is, after pressing an operation switch portion  75  next to a “selection of function” portion, the operator presses a “not use” operation switch portion  76  when an ordinary manufacturing operation is to be performed or presses a “use” operation switch portion  77  when the board re-recognition-check-stop function is to be activated. In this embodiment, since the board re-recognition-check-stop function is to be activated, the “use” operation switch portion  77  is pressed and then a “set” operation switch portion  78  is pressed.  
      After the printed board  6  is positioned on the XY table  3 , the board recognition process is performed before the chip component  5  is mounted on the printed board  6  and also performed after the chip component  5  is mounted thereon. Both the positions of the positioning mark M, which are recognized before and after the component  5  is mounted on the printed board  6 , are compared to judge whether or not a deference between these positions is within a predetermined range. When the difference is out of the predetermined range, the mounting apparatus is stopped because of an error. The board re-recognition-check-stop function works in this manner.  
      Next, description will be made on an operation of setting an allowable value for determining the predetermined range. First, when setting an allowable value X, the operator presses an operation switch portion  79  next to an “allowable value X” portion on the monitor. Then, a number operation switch portion (not shown) is displayed in a position where the “use” operation switch portion  77  and the “not use” operation switch portion  76  are displayed in the screen shown in  FIG. 15 . The operator inputs 0.100 mm, for example, by pressing the number operation switch portion, and presses the “set” operation switch portion  78 .  
      When setting an allowable value Y, the operator presses an operation switch portion  80  next to an “allowable value Y” portion. Then, as described above, the number operation switch portion (not shown) is displayed in the position where the “use” operation switch portion  77  and the “not use” operation switch portion  76  are displayed in the screen shown in  FIG. 15 . The operator inputs 0.100 mm, for example, by pressing the number operation switch portion, and presses the “set” operation switch portion  78 .  
      The allowable values X and Y thus set is stored in the RAM  62 . The CPU  61  compares both the positions of the positioning mark M recognized before and after the component  5  is mounted on the printed board  6 , and checks whether or not the difference of these positions is within the predetermined range, that is, within a range from −0.100 mm to +0.100 mm, in both the X and Y directions. When the difference is out of the predetermined range, the CPU  61  stops the electronic component mounting apparatus because of an error. The board re-recognition-check-stop function works in this manner.  
      With this structure, the operation of the electronic component mounting apparatus will be described hereafter. First, when a printed board  6  is shifted onto the supply conveyer from the upstream device (not shown), a printed board  6  on the supply conveyer is shifted onto the XY table  3  and a printed board  6  on the XY table  3  is shifted onto the discharge conveyer.  
      That is, by rotation of conveying belts of the supply conveyer, the XY table  3 , and the discharge conveyer, each of the printed boards  6  thereon is shifted to next one among these.  
      Then, as the rods of the cylinders (not shown) descend, the chute vertical movement levers rotate downward, and the printed board  6  supported by the conveying chutes  31  and  32  by the guide shafts descends together with the conveying chutes  31  and  32  and the chute supporting members.  
      By the conveying chutes  31  and  32  descending, the backup pins  37  inserted in the holes formed in the XY table  3  become in contact with the back surface of the printed board  6  to push and support the printed board  6  horizontally. Even if warped downward, the printed board  6  can be held straight by the backup pins  37  pushing the warped portion ( FIG. 8 ).  
      Furthermore, when the conveying chutes  31  and  32  descend, the positioning pin  42  is rotated by the drive source (not shown), and pushes the printed board  6  to the positioning pin  41  to fix it between the pins  41  and  42 , thereby positioning the printed board  6  in a lateral direction (in a conveying direction) ( FIGS. 4 and 7 ).  
      Furthermore, when the conveying chutes  31  and  32  finish descending, the cylinders  50  are activated to draw the rods  51  therein, the detection levers  45  rotate around the supporting axes  47  as fulcrums by pressure of the coil springs  48 , and thus the another end sides of the detection levers  45  which are the opposite side of the supported side thereof rise up. When the printed board  6  lies on the conveying belts  35 , the upper portions of another ends of the detection levers  45  push the printed board  6  up and press the printed board  6  to the block portions  55  formed in the conveying chutes  31  and  32  from downward, so that the printed board  6  is positioned in the vertical direction at its left and right ends ( FIGS. 9 and 10 ).  
      In this case that the printed board  6  is positioned by being pushed and pressed to the block portion  55  from downward by the upper portions of another end sides of the detection levers  45  when the detection lever  45  is rotated upward by the operation of the cylinder  50 , the light shield boards  56  do not lie in the upper bound positions, so that the light receiving elements  58 B receive light from the emissive elements  58 A. Therefore, the detection sensors  58  recognize the printed board&#39;s presence.  
      Since the detection sensors  58  recognize the printed board&#39;s presence, the XY table  3  and the printed board  6  are moved in the X and Y directions driven by the Y axis drive motor  2  and the X axis drive motor  4  with the printed board  6  pressed to the fixed conveying chute  31  by the pressing members  38  provided in the movable conveying chute  32  and supported at its back surface by the backup pins  37  on the XY table  3 , so that the board recognition camera  70  takes an image of the positioning marks M provided on the printed board  6 . Therefore, the recognition processing device  68  performs a recognition process to the image taken by the board recognition camera  70  to recognize the positions of the positioning marks M and the printed board  6 , and the positions of the positioning marks M and the printed board  6  are stored in the RAM  62 . That is, the recognition processing device  68  performs the recognition process to the image taken by the board recognition camera  70 , and the recognition result is sent to the CPU  61 .  
      Then, at the pickup station, the suction nozzle picks up the chip component fed by the predetermined component feeding unit  8 . When the mounting head  15  having the suction nozzle stops at above the component recognition camera  16  while the rotary table  13  sequentially rotates, the component recognition camera  16  takes an image of a bottom surface of the component  5  held by the suction nozzle. Then, the recognition processing device  68  performs the recognition process to the image taken by the component recognition camera  16  to recognize the position of the chip component  5 . That is, the recognition processing device  68  performs the recognition process to the image taken by the component recognition camera  16 , and the recognition result is sent to the CPU  61 .  
      Accordingly, the recognition result of the position of the printed board  6  calculated by the recognition processing device  68  is added to the positional shifting amount of the chip component  5  held by the suction nozzle. Thus, the CPU  61  which receives the results moves the XY table  3  in the X and Y directions by driving the X axis drive motor  4  and the Y axis drive motor  2 , and rotates the mounting head  15  (suction nozzle) by a θ angle by driving the θ axis drive motor  17 A, thereby completing correction in the X and Y directions and in the rotation angle around the vertical axis.  
      In this manner, with the mounting head  15  and the printed board  6  set in corrected positions, the chip component  5  is mounted on the printed board  6  according to the mounting data stored in the RAM  62 . When all the chip components  5  are mounted on the printed board  6  according to the mounting data, the XY table  3  is moved and the board recognition camera  70  takes an image of the positioning marks M provided on the printed board  6  again. The recognition processing device  68  then performs the recognition process to the image taken, and the positions of the marks M are stored in the RAM  62 .  
      Then, the CPU  61  compares both the positions of each of the positioning marks M recognized before and after the component  5  is mounted on the printed board  6 , and checks whether or not the difference between the positions is within the predetermined range stored in the RAM  62 , that is, within the range from −0.100 mm to +0.100 mm, in both the X and Y directions. When the difference is within the range, the ordinary operation is performed.  
      In the ordinary operation, the XY table  3  returns to its original position. As the cylinders (not shown) is operated to raise the rods, the chute vertical movement levers rotate upward and the conveying chutes  31  and  32  and the chute supporting members rise up together, supporting the printed board  6  by the guide shafts. Then, by rotation of conveying belts of the supply conveyer, the XY table  3 , and the discharge conveyer, each of the printed boards  6  thereon is shifted onto next one among these. The printed board  6  supported by the conveying chutes  31  and  32  is shifted onto the discharge conveyer and then to the upstream device.  
      On the other hand, as described above, in the case that the difference is out of the range when the CPU  61  checks whether or not the difference of both the positions of each of the positioning marks M before and after the component  5  is mounted on the printed board  6  is within the predetermined range stored in the RAM  62 , that is, within the range from −0.100 mm to +0.100 mm, in both the X and Y directions, the CPU  61  controls the electronic component mounting apparatus to stop because of an error. That is, the mounting apparatus stops transferring thus identified printed board to the downstream process and mounting operation to the next printed board. Then, the operator of the mounting apparatus operates on the touch panel to transfer the identified printed board to a position for recovering the identified printed board. After the identified printed board is recovered, the operator operates on the touch panel to resume the component mounting operation. Alternatively, the operate may just place on the identified printed board a marking to indicate defective printed board and resume the component mounting operation. In this embodiment, the reference to determine the positions of the printed boards is the mounting apparatus itself.  
      When the difference is out of the range, this is displayed on the monitor  71  as shown in  FIG. 16 . That is, on the monitor  71 , an upper row of ( 1 ) shows both X coordinates of one of the positioning marks M recognized when the manufacturing process starts (before the component is mounted on the printed board  6 ) and when the re-recognition process is performed (after the component is mounted on the printed board  6 ). A lower row of ( 1 ) shows both Y coordinates of one of the positioning marks M recognized when the manufacturing process starts (before the component is mounted on the printed board  6 ) and when the re-recognition process is performed (after the component is mounted on the printed board  6 ). An upper row of ( 2 ) shows both X coordinates of another one of the positioning marks M recognized when the manufacturing process starts (before the component is mounted on the printed board  6 ) and when the re-recognition process is performed (after the component is mounted on the printed board  6 ). A lower row of ( 2 ) shows both Y coordinates of another one of the positioning marks M recognized when the manufacturing process starts (before the component is mounted on the printed board  6 ) and when the re-recognition process is performed (after the component is mounted on the printed board  6 ). On this monitor  71 , the Y coordinate of another one of the positioning marks M can be recognized as shifted by 0.104 mm, so that “defective” is displayed on the monitor  71  as a latest recognition result. It is noted that when such an error occurs, the error is not limited to be informed visually and can be informed auditorily by an informing device such as by voice or a buzzer.  
      When an improper positioning pin  42  for a printed board  6  is placed in the XY table  3 , the positioning of the printed board  6  is not stable and as a result the mounting position with respect to the printed board  6  may shift from a predetermined position. Likewise, when the printed bard  6  is warped upward and positioned for component mounting, the descending suction nozzle pushes down a portion of the printed board  6  that is located at a level higher than a proper horizontal level because of the wrapping. As a result, the printed board  6  is pushed out of the proper position for the component mounting. In this embodiment, however, the printed board  6  manufactured in this manner can be treated as a defective, so that only the printed boards having high mounting accuracy can be manufactured. That is, after the electronic component mounting apparatus stops and the informing device informs the operator of that, the operator removes the causes of the error (e.g. mistakenly replaced positioning members) so that only the printed boards having higher mounting accuracy can be manufactured.  
      Although the above embodiment uses the XY table  3  that can move to any position in the X and Y directions on a horizontal plane and a suction nozzle that vertically moves at a determined position, a table that does not move in the horizontal direction can be used instead of the XY table  3  when the suction nozzle can move vertically and also in the X and Y directions on the horizontal plane.  
      Furthermore, the embodiment is applied to the electronic component automatic mounting apparatus, modifications are possible as long as these are within the scope of the invention. For example, the invention can be applied to a coating device (i.e. a so-called dispenser device) for coating a coating agent such as a desiccant on a board and so on.  
      Although particular preferred embodiment of the invention has been disclosed in detail, it will be recognized that variations or modifications of the invention are possible based on the disclosure and lie within the scope of the invention.