Abstract:
An electronic component mounting apparatus includes a component feeding device that supplies an electronic component to a pickup position, a suction nozzle that picks up the electronic component supplied to the pickup position and mounts the picked up electronic component on a printed board, a height level detection device that measures height levels of the printed board positioned in a mounting position, a monitor graphically that displays a warping state of a sample printed board positioned in the mounting position based on height level measurements by the height level detection device on predetermined positions of the sample printed board, a setting device that sets measurement positions for actual mounting operations using the monitor, a converting device that converts the set measurement positions into coordinates on the printed board, and a memory that stores the converted coordinates of the set measurement position.

Description:
CROSS-REFERENCE OF THE INVENTION 
     This application claims priority from Japanese Patent Application No. 2007-117762, the content of which is incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an electronic component mounting apparatus for picking up electronic components from a component feeding device by suction by suction nozzles and mounting the electronic components on a positioned printed board. In detail, the invention relates to a method of mounting an electronic component and an electronic component mounting apparatus in which electronic components are picked up from a component feeding device by suction by suction nozzles, a height level of a positioned printed board is measured by a height level detection device, and the electronic components are mounted on the printed board based on the measurement result of this height level detection device. 
     2. Description of the Related Art 
     A general electronic component mounting apparatus is disclosed in Japanese Patent Application publication No. 2006-286707 and so on, for example. In some cases, due to a warp of a printed board, electronic micro-components may be brought back instead of mounted, crack, or scatter solders in the mounting operation. Therefore, the lowering of suction nozzles during the mounting of electronic components is controlled, using a device for detecting a height level of a board such as a laser displacement gauge and based on its measurement result. 
     However, a plurality of positions for height measurement need be set on a printed board, taking account of the warping state or curvature of the board, and inputting the coordinates of the measurement positions is a complicated work. The invention realizes setting of measurement positions suitable for a warping state of a printed board and an easy work of setting the measurement positions. 
     SUMMARY OF THE INVENTION 
     The invention provides a method of mounting an electronic component in which an electronic component is picked up from a component feeding device by suction by a suction nozzle, a height level of a positioned printed board is measured by a height level detection device, and the electronic component is mounted on the printed board based on the measurement result of the height level detection device, the method including: measuring a warping state of a positioned printed board as a measurement sample by the height level detection device; displaying the warping state of the printed board graphically on a monitor based on the measurement result; setting a measurement position on the displayed graphic; and converting the set measurement position into coordinates on the printed board and storing the coordinates in a memory. 
     The invention also provides an electronic component mounting apparatus in which an electronic component is picked up from a component feeding device by suction by a suction nozzle, a height level of a positioned printed board is measured by a height level detection device, and the electronic component is mounted on the printed board based on the measurement result of the height level detection device, including: a monitor graphically displaying a warping state of a positioned printed board as a measurement sample based on a result of measuring the warping state of the printed board by the height level detection device; a setting device setting a measurement position on the displayed graphic; a converting device converting the measurement position set by the setting device into coordinates on the printed board; and a memory storing the converted coordinates of the set position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of an electronic component automatic mounting apparatus. 
         FIG. 2  is a control block diagram. 
         FIG. 3  is a flow chart. 
         FIG. 4  is a view of a screen three-dimensionally displaying a warping state of a printed board. 
         FIG. 5  is a view of a screen displaying a warping state of a printed board by contour lines. 
         FIG. 6  is a view of a screen three-dimensionally displaying a state where measurement points are set. 
         FIG. 7  is a view of a screen displaying a state where measurement points are set by contour lines. 
         FIG. 8  is a table showing mounting data. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An embodiment of an electronic component mounting apparatus for mounting electronic components on a printed board will be described referring to figures.  FIG. 1  is a plan view of an electronic component mounting apparatus  1 , and a plurality of component feeding units  3  supplying various electronic components to these component pickup portions (component suction positions) one by one is arrayed on a base  2  of the apparatus  1 . A supplying conveyer  4 , a positioning portion  5  and a discharging conveyer  6  are provided between the opposite groups of component feeding units  3 . The supplying conveyer  4  carries a printed board P received from an upstream device to the positioning portion  5 , the printed board P is positioned by a positioning mechanism (not shown) on the positioning portion  5 , electronic components are mounted on the printed board P, and the printed board P is carried to the discharging conveyer  6 . 
     Numerals  8 A and  8 B indicate a pair of beams extending in the X direction, which separately move in the Y direction along a pair of left and right guides  11  above a printed board P or above the component pickup portions (component suction positions) of the component feeding units  3  by rotation of screw axes  10  driven by Y axis motors  9 , respectively. 
     The beams  8 A and  8 B are respectively provided with mounting heads  7 A and  7 B moving in the longitudinal direction of the beams  8 A and  8 B, that is, in the X direction along guides (not shown) by X axis motors  12 . Two vertical axis motors  13  vertically moving two suction nozzles  17 A and  17 B or two suction nozzles  17 C and  17 D are mounted on each of the mounting heads  7 A and  7 B, and two θ axis motors  14  rotating these suction nozzles about vertical axes are further mounted thereon. Therefore, the suction nozzles of each of the two mounting heads  7 A and  7 B are movable in the X and Y directions, rotatable about vertical axes, and movable vertically. 
     Numerals  16  indicate component recognition cameras, which take images of electronic components held by the suction nozzles  17 A,  17 B,  17 C and  17 D. Numerals  18  indicate height level detection devices such as laser displacement gauges provided on the mounting heads  7 A and  7 B respectively, which measure a height level of a printed board P positioned on the positioning portion. 
     Next, referring to a control block diagram in  FIG. 2 , a CPU  30  controls the members of the electronic component mounting apparatus  1 , and is connected to a ROM  31  storing programs for this control and a RAM  32  storing various data through bus lines  33 . A monitor  34  displaying an operation screen or the like and a touch panel switch  35  as input means formed on the display screen of the monitor  34  are connected to the CPU  30  through an interface  36 . The Y axis motor  9  and so on are connected to the CPU  30  through a drive circuit  38  and the interface  36 . The touch panel switch  35  may be replaced by a keyboard or other input means, and operation means such as a mouse may be further connected to the CPU  30 . 
     The RAM  32  is stored with mounting data for each of types of printed boards P for the component mounting operation, in which data about mounting coordinates of each of electronic components in the X and Y directions on the printed board P and the angle thereof, data about the alignment numbers of the component feeding units  3  or the like are stored in mounting order (in step number order). The RAM  32  is also stored with data about types of electronic components corresponding to the alignment numbers of the component feeding units  3 , i.e., component disposition data, and further stored with component library data about the lengths of the electronic components in the X and Y directions and the thicknesses thereof, nozzle IDs of suction nozzles used for electronic components, or the like classified by the component IDs. 
     Furthermore, the RAM  32  is also stored with numerous measurement positions for measuring a warping state of a printed board P by the height level detection device  18 , for example, coordinate data (measurement position data) about numerous measurement positions finely set at equal intervals over the whole regions of a printed board P. 
     A numeral  37  is a recognition processing device connected to the CPU  30  through the interface  36 , which performs recognition processing to an image taken and stored by the component recognition camera  16  and sends the processing result to the CPU  30 . In detail, the CPU  30  outputs a command to perform recognition processing (such as calculation of an positional shifting amount) to an image taken by the component recognition camera  16  to the recognition processing device  37 , and receives the recognition processing result from the recognition processing device  37 . However, the measurement points are not used when electronic components are mounted. 
     Selection may be made whether the warping state of the printed board P is displayed three-dimensionally as shown in  FIG. 4  or by contour lines as shown in  FIG. 5 , based on a measurement result about height levels measured by the height level detection device  18  according to the measurement position data, by touch-operating the touch panel switch  35  while watching a selection screen displayed on the monitor  34 . Therefore, according to the selected display program stored in the ROM  31 , the CPU  30  displays the warping state of the printed board P on the monitor  34  three-dimensionally or by contour lines. 
     The three-dimensional display of the printed board P may be shifted, that is, the side of the printed board P to watch may be changed by operation of an operator. 
     In this case, for example, the screen indicates that the A region of the printed board P is on the level higher than the reference level by 0.550 to 0.600 mm by warping upward and similarly the B region is on the level higher than the reference level by 0.500 to 0.550 mm. 
     The height levels may be displayed with different colors or patterns in each of the regions, or with different colors in each of the grid-partitioned regions of the substrate, for example. 
     Next, a description will be given referring to a flow chart in  FIG. 3 , hereafter. First, by an operator, a printed board P as a measurement sample is mounted on the positioning portion  5 , and the positioning mechanism is activated to position the printed board P three-dimensionally in the X, Y and vertical directions by touch-operating the touch panel switch  35  displayed on the monitor  34 . Then, the backup base (not shown) which has a plurality of holes where backup pins necessary for the printed board P for the manufacturing process are inserted is lifted up to apply the backup pins to the back surface of the printed board P and to push up and support the board P horizontally. 
     Then, the warping state of the printed board P is measured by touch-operating the touch panel switch  35 . At this time, according to the touch-operation of the touch panel switch  35 , the CPU  30  controls the X axis motor  12  and the Y axis motor  9  to move the height level detection device  18 , controls the height level detection device  18  to measure the height levels of the printed board P in the measurement positions based on the coordinate data (measurement position data) about numerous measurement positions stored in the RAM  32 , and stores the measurement result in the RAM  32 . 
     Then, the CPU  30  graphically displays the warping state of the printed board P on the monitor  34  as shown in  FIG. 4  when the three-dimensional display is selected or as shown in  FIG. 5  when the contour line display is selected, based on the measurement result. 
     At this time, the operator may set the measurement positions on either of the displays on the screen by touch-operation on the screen. In detail, touching the positions to be measured means operating the touch panel switch  35  on the monitor  34 , and thus the operator easily sets the measurement positions while watching the warping state of the board which is graphically displayed. In this case, black portions in  FIG. 6  are the set positions, and white circle portions in  FIG. 7  are the set positions. The position may be set by indicating it by a cursor (not shown) and pressing an enter key, or by clicking a mouse. 
     One of the screens of  FIG. 6  and  FIG. 7  may be used to set some positions by touch-operation, and then the other screen may be selected to set other positions. At this time, the measurement positions which are already set remain displayed on the switched screen. The screen may be switched after all the measurement positions are set, and enhanced setting of measurement positions may be achieved by checking both the screens. Furthermore, the set measurement position may be canceled to omit an unnecessary measurement position. The canceling method includes clicking a mouse on the set points twice, or using a touch panel switch, for example, touching a “delete” portion displayed on the screen. 
     After the setting, the CPU  30  converts each of the set positions into coordinates on the printed board P, writes the coordinates of each of the set positions in the top of the mounting data as shown in  FIG. 8 , and stores the data in the RAM  32 . For example, for the step number  0001 , XX 1  and YY 1  are written as the X coordinate and the Y coordinate, and “W” is written as the command of the mounting data about the measurement positions, which is distinguished from the mounting data about the mounting positions of the electronic components. 
     Hereafter, an operation with the above structure will be described. First, a printed board P is received by the supplying conveyer  4  from an upstream device (not shown), and the printed board P on the supplying conveyer  4  is carried onto the positioning portion  5 . 
     At this time, the printed board P is positioned three-dimensionally in the X, Y and vertical directions by the positioning mechanism, and the backup base (not shown) having the holes where the backup pins necessary for the printed board P for the manufacturing process are inserted is lifted up to apply the backup pins to the back surface of the printed board P and to push up and support the board P horizontally. 
     The positioning operation for the printed board P is completed in this manner. When judging the completion of the positioning operation, the CPU  30  controls the X axis motor  12  and the Y axis motor  9  to move the mounting head  7 A or  7 B and the detection device  18 . In this case, the CPU  30  moves the height level detection device  18  to the position above the coordinates of the measurement position indicated by the step number  0001  and detects the height level of the printed board P there according to the mounting data shown in  FIG. 8  stored in the RAM  32 , and similarly moves the height level detection device  18  to the position above the coordinates indicated by the step number  0002  and detects the height level of the printed board P there. The CPU  30  then repeats the detection of the height levels on all the set measurement coordinates, and stores the height level data as the measurement values in the RAM  32 . 
     At this time, the number of measurement positions is minimized and the time for detecting the height levels of the board is reduced since the measurement positions are set on the screen graphically displaying the state of the board. 
     Then, the suction nozzle  17 A,  17 B,  17 C or  17 D picks up an electronic component to be mounted from the predetermined component feeding unit  3 , according to the mounting data stored in the RAM  32 , where the position of the X and Y coordinates and the rotation angle about the vertical axis for mounting the electronic component on the printed board P positioned on the positioning portion  5 , the FDR number (the alignment number of each of the component feeding units  3 ) and so on are set, next to the mounting data about the measurement positions. 
     In detail, if the suction nozzle  17 A of the mounting head  7 A corresponds to the type of the electronic component, the suction nozzle  17 A moves to the position above the component feeding unit  3  storing the first electronic component to be mounted. In detail, as described above, the mounting head  7 A is moved in the Y direction by the beam  8 A moving along the pair of guides  11  by the Y axis motor  9 , and is moved in the X direction by the X axis motor  12 . The predetermined feeding unit  3  is already driven and the electronic component is ready to be picked up on the component pickup position. Then, the vertical axis motor  13  is driven to lower the nozzle  17 A and the nozzle  17 A picks up the electronic component by suction. The suction nozzle  17 B then moves to the position above the component feeding unit  3  storing the next electronic component to be mounted and picks up the electronic component. 
     Furthermore, the suction nozzles  17 A and  17 B move to the position above the component recognition camera  16 , and the component recognition camera  16  takes images of the electronic components held by suction, and the recognition processing device  37  performs recognition processing to the images. Based on the recognition result, the beam  8 A and the mounting head  7 A are moved again, and the suction nozzles  17 A and  17 B correct the positional shifts of the components by adding the component recognition result to the mounting coordinates in the mounting data and mount the electronic components on the printed board P respectively. 
     At this time, the suction nozzles  17 A and  17 B, which pick up electronic components by suction and mount the electronic components on a printed board P by rotating by the θ axis motors  14  and lowering by the vertical axis motors  13  respectively, use the measurement values when mounting the electronic components. In detail, based on the measurement values of the height levels of the printed board P corresponding to the component mounting positions, the CPU  30  controls the lowering of the suction nozzles  17 A and  17 B. It means that the CPU  30  decreases the lowering amount when the printed board P is warped upward, and increases the lowering amount when the printed board P is warped downward. 
     As described above, the invention provides an electronic component mounting apparatus which achieves setting of measurement positions suitable for a warping state of a printed board and provides an easy work of setting the measurement positions. 
     Although an embodiment of the invention is described above, those skilled in the art would understand that various substitutions, changes or modifications are possible based on the above description and the invention includes the various substitutions, changes or modifications within the scope of the invention.