JP2006019469A - Method and apparatus of packaging electronic part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of packaging an electronic part which can package certainly the electronic part even if a printed circuit substrate has various types of warps. <P>SOLUTION: The method of packaging the electronic part includes a step of measuring the height from a preset reference position to the printed circuit substrate 4 over a plurality of sets of a plurality of measuring points with the plurality of the measuring points, as a set to measure the local warp of the printed circuit substrate 4 positioned at the part packaging position B of an apparatus 1 of packaging the electronic part; a step of calculating the planar shape for each set by averaging the measured values obtained by the measurement for each set; a step of correcting the stroke of a part packaging means 15 provided in a packaging head 13 with plane shape data obtained by the calculation; and a step of packaging the electronic part 5 on the printed circuit substrate 4 by the part packaging means 15 corrected at its stroke. Thus, even if the printed circuit substrate 4 has the various types of the warps, the electronic part 5 can be packaged certainly. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electronic component mounting method and a mounting apparatus for mounting an electronic component on a printed circuit board.

  A large number of electronic components are mounted on a printed circuit board used in an electronic device or the like. Many of these electronic components are automatically mounted at predetermined positions on the printed circuit board by a mounting apparatus.

  A conventional mounting apparatus that mounts electronic components on a printed circuit board uses a mounting head that is movable in the X-axis and Y-axis directions after the printed circuit board conveyed by the substrate conveying conveyor is positioned at a predetermined position and clamped by a clamp. The picked-up electronic component is moved to a predetermined position on the printed board and mounted.

  In addition, the back side of the printed circuit board is supported by a plurality of backup pins, and even if the printed circuit board is slightly curved (downward warped), the back-up pins can correct the downward warping. .

  However, if the printed circuit board is curved (upward warped) on the surface side, it cannot be corrected with the backup pin. Therefore, when an electronic component is mounted on such a printed circuit board with a mounting head, the electronic component collides with the printed circuit board. The problem that a printed circuit board and an electronic component are damaged arises.

In order to improve such a problem, by measuring the height from a predetermined reference position to the mounting position of the printed circuit board, and adjusting the height of the mounting head when mounting components relative to the mounting position based on the obtained height An electronic component mounting method and a mounting apparatus have been proposed in which an electronic component can be accurately and appropriately mounted even when the printed circuit board is warped (for example, Patent Document 1).
JP 2002-185193 A

  However, in recent years, lead-free lead-free products have been developed because of the high density and thinning of printed circuit boards used due to higher functionality and higher performance of electronic devices, etc., as well as consideration for adverse effects on human bodies and environmental pollution. Although the use of solder is widespread, lead-free solder has a higher melting point than conventional eutectic solder, and therefore, when reflow soldering is employed, the warping of the printed circuit board becomes diverse.

  Therefore, like the electronic component mounting method described in Patent Document 1, the height from a predetermined reference position to the mounting position of the printed circuit board is measured, and the component relative to the mounting position is based on the obtained height. A device that adjusts the height of the mounting head during mounting cannot cope with a wide variety of warping of the printed circuit board. As a result, the electronic component collides with the printed circuit board and the electronic component or the printed circuit board There is a problem that it is impossible to prevent mounting defects such as breakage, electronic component jumping, electronic component misalignment or shortage, and electronic component floating from the printed circuit board.

  The present invention has been made in order to improve such a conventional problem, and an object of the present invention is to provide an electronic component mounting method and mounting apparatus that can securely mount an electronic component even if the printed circuit board has various warping. It is what.

  An electronic component mounting method according to the present invention is an electronic component mounting method for mounting an electronic component on a printed circuit board using a mounting apparatus having a mounting head movable in the X-axis and Y-axis directions. A step of measuring the height from the preset reference position to the printed board over a plurality of sets with a plurality of measurement points as a set in order to measure the local warpage of the printed board positioned at the component mounting position; The measurement values obtained by the measurement are averaged for each group, and the stroke of the component mounting means provided in the mounting head is calculated by the process of calculating the planar shape for each group and the planar shape data obtained by the calculation. A correcting step and a step of mounting an electronic component on the printed circuit board by the component mounting means whose stroke is corrected.

  Due to the above-mentioned methods, high density, thinning, and reflow soldering are adopted, so even if the printed board has a wide variety of warping locally, the printed circuit board has a component mounting means that corrects the stroke according to the warping. Since electronic components can be mounted on the printed circuit board, the electronic components may collide with the printed circuit board and damage the electronic components or the printed circuit board. The electronic components may jump, the electronic components may be misaligned or missing. Mounting defects such as floating can be reliably prevented.

  According to the electronic component mounting method of the present invention, when measuring the local warpage of a printed circuit board, the printed circuit board is partitioned into a matrix, the corners of each cell are set as measurement points, and the cell 1 A plurality of measurement points are measured as a set.

  By the above method, it is possible to set a fine measurement position by selecting the size of the grid according to the mounting density, the size of the electronic component to be mounted, the degree of local warpage of the printed circuit board, etc. Since the measurement position can be set by coordinates, it is easy to create a program, and when there is little warping of the printed circuit board, the measurement area can be reduced by setting the size of the grid larger. Efficiency can be improved.

  An electronic component mounting apparatus according to the present invention includes a mounting head that is movable in the X-axis and Y-axis directions, a component mounting that is provided on the mounting head so as to be movable up and down, and that takes out an electronic component from a component supply means and mounts it on a printed circuit board. Means for measuring a local warp of a printed circuit board provided at a mounting head and positioned at a component mounting position of the mounting apparatus, from a preset reference position to the printed circuit board. A height measuring means for measuring the height over a plurality of sets with a plurality of measurement points as a set, and a measurement value obtained by the measurement is averaged for each set, and a planar shape is calculated for each set, It comprises control means for correcting the descending stroke of the component mounting means based on the planar shape data obtained by the calculation.

  Due to the above configuration, high density, thinning, and reflow soldering are adopted, so even if the printed board has a wide variety of warping locally, the printed circuit board has a component mounting means that corrects the stroke according to the warping. Since electronic components can be mounted on the printed circuit board, the electronic components may collide with the printed circuit board and damage the electronic components or the printed circuit board. The electronic components may jump, the electronic components may be misaligned or missing. Mounting defects such as floating can be reliably prevented.

  Moreover, since it can be implemented simply by inputting a measurement program to an existing mounting apparatus, it is economical.

  According to the electronic component mounting method and the mounting apparatus of the present invention, even if the printed board has a wide variety of warping locally, the electronic component is placed on the printed board by the component mounting means in which the stroke is corrected according to the warping. Since it can be mounted, the electronic component collides with the printed circuit board and the electronic component or the printed circuit board is damaged, the electronic component jumps, the electronic component is misaligned or missing, and the electronic component is lifted from the printed circuit board. Defects can be reliably prevented.

  Embodiments of the present invention will be described in detail with reference to the drawings.

  1 is a front view showing a mounting line for electronic components, FIG. 2 is an enlarged front view in the vicinity of a mounting head provided in the mounting apparatus, FIG. 3 is an enlarged plan view thereof, FIG. 4 is a block diagram of a control means, and FIG. FIG. 6 is a flowchart showing the operation at the time of component mounting.

  The electronic component mounting line shown in FIG. 1 includes a plurality of mounting apparatuses 1 (three are shown in the embodiment) from the upstream side to the downstream side with respect to the conveyance direction (arrow A) of the printed circuit board 4. Are arranged in order, and on the upstream side of the mounting device 1, there are devices 2 for performing pre-processes such as a printing machine, a dispenser and a solder inspection machine, and on the downstream side, such as a reflow soldering device and a curing furnace. A device 3 for performing a post-process is installed.

  The mounting apparatus 1 for mounting the electronic component 5 on the printed circuit board 4 has a base 1a as shown in FIG. 3, and the printed circuit board 4 that has been processed in the previous step is mounted on the base 1a. Substrate transport means 6 for carrying into 1 is installed.

  The board conveying means 6 is formed by a conveyor, for example, and the interval can be adjusted according to the size of the printed board 4. The printed board 4 carried into the mounting apparatus 1 by the board conveying means 6 is The positioning means is placed on a positioning means (not shown) installed at a component mounting position B on the table 1a. The positioning means includes a plurality of backup pins that support the printed circuit board 4 from below and a predetermined position. It comprises a clamper that clamps and fixes both sides of the printed circuit board 4 positioned.

  Above the substrate transport means 6, a pair of guide rails 7 that are separated in the substrate transport direction A and arranged in parallel in the Y-axis direction orthogonal to the substrate transport direction A are installed. A shaft carrier 8 is supported so as to be movable in the Y-axis direction, and a support frame 9 is horizontally placed between the Y-axis carriers 8 in the X-axis direction orthogonal to the Y-axis.

  Both end sides of the ball screw shaft 10a constituting the Y-axis driving means 10 are rotatably supported on the side surface of the guide rail 7 located on the downstream side, and one end side of the ball screw shaft 10a is mounted on the base 1a. A Y-axis drive motor 10b composed of a servo motor provided on the ball screw shaft 10a is connected, and a ball nut (not shown) screwed to the ball screw shaft 10a is attached to one Y-axis carrier 8, The support frame 9 can be moved in the Y-axis direction via the Y-axis carrier 8 by rotating the ball screw shaft 10a forward and backward by the shaft drive motor 10b.

  The support frame 9 is formed in a girder shape, and a pair of guide rails 12 are installed on one side surface so as to be separated in the vertical direction, and the mounting head 13 is supported on these guide rails 12 so as to be movable in the X-axis direction. In addition, both end sides of the ball screw shaft 14a constituting the X-axis drive means 14 are rotatably supported between the guide rails 12.

  One end of the ball screw shaft 14a is connected to an X-axis drive motor 14b made of a servo motor provided at the downstream end of the support frame 9, and a ball nut (see FIG. (Not shown) is attached to the mounting head 13, and the mounting head 13 can be moved in the X-axis direction by rotating the ball screw shaft 14 a forward and backward by the X-axis drive motor 14 b.

  As shown in FIG. 2, component mounting means 15 including a plurality of suction nozzles provided in the vertical direction is arranged in parallel in the X-axis direction on the front surface of the mounting head 13, and the lower end side of these component mounting means 15 The electronic part 5 accommodated in the component supply means 16 can be sucked by the nozzle portion 15a.

  The component supply means 16 is composed of a plurality of rows of tape feeders 16a installed on the base 1a so as to be spaced apart from each other in the Y-axis direction and sandwiching the component mounting position B therebetween. The nozzle parts 15a of the component mounting means 15 provided in the mounting head 13 attract the electronic components 5 sent out individually, and the tape feeder 16a has no electronic components 5 or the electronic components 5 to be mounted. It can be exchanged when it changes.

  The component mounting means 15 provided on the mounting head 13 can be swung by the swiveling means 13a so as to be able to cope with the case where the orientation of the electronic component 5 to be mounted on the printed board 4 is changed, and each component mounting means 15 by the lifting / lowering means 13b. The height measuring means for detecting the height to the upper surface of the printed circuit board 4 positioned at the component mounting position B is located in the vicinity of the component mounting means 15 located on the upstream side. 17 is provided.

  The height measuring unit 17 uses, for example, a distance sensor that can measure the height from a preset reference position to the surface of the printed circuit board 4 without contact, and the printed circuit board 4 is moved along with the movement of the mounting head 13. The heights of the plurality of measurement points C on the upper surface can be measured in a short time, and the measurement values measured by the height measurement means 17 are sent to the control means 18 shown in FIG. The height difference for each coordinate is calculated instantaneously.

  On the base 1a of the mounting apparatus 1, a component recognition unit 20 is installed, for example, in the vicinity of the upstream side of one tape feeder 16a.

  The component recognition unit 20 identifies the electronic component 5 attracted by the component mounting unit 15, and includes an illumination lamp that illuminates the electronic component 5 from below, a CCD camera that images the electronic component 5, an illumination lamp, and a CCD camera. An image of the electronic component 5 which is composed of a housing (not shown) or the like and which is picked up by the CCD camera is sent to the control means 18 for image processing, and the electronic component 5 is identified. Yes.

  Next, a mounting method for mounting the electronic component 5 on the printed circuit board 4 using the mounting apparatus 1 configured as described above will be described with reference to FIGS. 4, 5, and 6.

  A mounting program for instructing which electronic component 5 is to be mounted at which position on the printed circuit board 4 is input in advance to the control means 18 that controls the mounting apparatus 1.

  In this mounting program, in addition to the mounting position of the electronic component 5, the descending stroke of the component mounting means 15 provided in the mounting head 13, the pushing amount to the printed circuit board 4, etc. are programmed for each component. If the board 4 has various warpages, the pre-programmed descending stroke of the component mounting means 15 and the amount of pushing into the printed circuit board 4 cannot cope with various warpages and cause mounting defects. Become.

  In order to prevent this, the control means 18 incorporates a measurement program for measuring the height of a plurality of points on the printed circuit board 4 separately from the mounting program.

  For example, as shown in FIG. 5, the printed circuit board 4 is partitioned into a matrix, the height from the reference position is measured with the four corners of each square as a set of measurement points C, and the obtained measurement values are measured. Are sent to the control means 18 and the plane shape data of each square is calculated from the average value of each measurement value by the calculation unit 18a.

  Further, when the printed circuit board 4 is partitioned into a matrix, the measurement accuracy increases as the size of the cell is reduced, but the number of measurement points C increases and the measurement takes time, so that the mounting efficiency decreases.

  Therefore, it is desirable to determine the size of the matrix grid based on the mounting density of the printed circuit board 4 and the degree of local warpage.

  When the input of the mounting program and the program for instructing the measurement point C to the control means 18 is completed, when the operation of the mounting line is started, the printed board 4 processed in the previous process is transferred to the components of the first stage mounting apparatus 1 by the board transport means 6. It is carried into the positioning means provided at the mounting position B, positioned by the positioning means in step S1 of the flowchart shown in FIG. 6, and then fixed by the clamper.

  Thereafter, the X-axis driving means 14 and the Y-axis driving means 10 are controlled by a control signal sent from the control means 18, and the mounting head 13 provided with the height measuring means 17 moves on the printed circuit board 4 in the X-axis and Y-axis directions. The height measuring means is stopped at the measurement point C of the printed circuit board 4 where the height is measured first, and from the reference position at the measurement point C at the four corners of the first square to the surface of the printed circuit board 4. Is measured in step S2 of the flowchart, and a set of four points is sent to the control means 18 together with the coordinates of the measurement point C.

  In step S3 of the flowchart, the control unit 18 obtains a plane function from the measured values sent from the height measuring unit 17 as a set, calculates a plane shape from the average value for the first square, It is memorize | stored in the memory | storage means 18b for every coordinate of a mesh as shape data.

  After the plane shape of the entire cell is calculated as described above and the plane shape data is stored in the storage means 18b, the mounting program is then executed to start mounting the electronic component 5 on the printed circuit board 4.

  When the electronic component 5 is mounted, the X-axis drive unit 14 and the Y-axis drive unit 10 are controlled by a control signal sent from the control unit 18 to accommodate the electronic component 5 to be mounted first. The mounting head 13 is moved to 16 a and the nozzle portion 15 a of the component mounting means 15 provided on the mounting head 13 sucks the electronic component 5.

  Thereafter, the mounting head 13 is moved to the component recognition means 20 provided on the upstream side of the tape feeder 16a, and the electronic component 5 attracted to the component mounting means 15 is identified, and the electronic component to be mounted on the printed circuit board 4 If it is confirmed that it is 5, the mounting head 13 is moved to a position where the electronic component 5 is mounted at the beginning of the printed circuit board 4.

  At the same time, the control means 18 reads the planar shape data of the mounting position stored in advance in the storage means 18b, and corrects the descending stroke of the component mounting means 15 set in advance in step S4 of the flowchart with the planar shape data. Set an appropriate lowering stroke.

  In other words, when the mounting position of the printed circuit board 4 on which the electronic component 5 is mounted is warped downward, the downward movement stroke of the component mounting means 15 is corrected so as to increase. It correct | amends so that 15 downward strokes may reduce.

  As described above, when the descending stroke of the component mounting means 15 is set to an appropriate value according to the local warpage of the printed circuit board 4, the electronic component 5 is brought into contact with the upper surface of the printed circuit board 5 by the component mounting means 15. After the lowering, the component mounting means 15 is further lowered by a preset pushing amount, and the electronic component 5 is mounted on the printed circuit board 4 in step S5 of the flowchart.

  After the above operation is repeated and all the electronic components 5 to be mounted are mounted by the first stage mounting apparatus 1, the clamper of the positioning unit is released in step S6 of the flowchart, and the printed circuit board 4 is moved to the next by the substrate transfer unit 6. It is transported to the mounting device 1 and mounts the electronic component 5 in the same manner as described above. Plane shape data at each mounting position of the printed circuit board 4 measured by the first mounting device 1 is sent to each mounting device 1 in advance. By storing in the storage means 18b provided in the control means 18 of each mounting apparatus 1, it is not necessary to measure the height of the mounting position of the printed circuit board 4 every time the printed circuit board 4 is loaded. Although the efficiency is improved, the height of the mounting position of the printed circuit board 4 may be measured every time the printed circuit board 4 is carried into each mounting apparatus 1.

  When mounting of all the electronic components 5 is completed by the mounting apparatus 1 located on the most downstream side, the printed circuit board 4 is transported to the device 3 for performing the post-process by the board transport means 6 and is subjected to a post-process such as reflow soldering. Processing is performed.

  In the above embodiment, the printed circuit board 4 is partitioned into a matrix and the heights of the four corners of each square are measured as one set. However, a plurality of points around the square, for example, three or five points are measured. Planar shape data may be obtained, and when the mounting position of the electronic component 5 extends over the grid, the range including the adjacent grid is measured, and the obtained measurement values are averaged as one set. Alternatively, the printed circuit board 4 may not be partitioned into a matrix, and the height of a plurality of locations around the mounting position of the electronic component 5 may be measured to obtain planar shape data of the mounting position.

  In the above embodiment, the electronic component 5 is mounted after the height of the entire printed circuit board 4 is measured first. However, while the height measurement of the mounting position and the mounting of the electronic component 5 are alternately repeated. The electronic component 5 may be mounted on the printed circuit board 4, and a local sensor of the printed circuit board 4 may be detected as a surface by using a line sensor or the like for the height measuring means 17.

  The electronic component mounting method of the present invention is capable of mounting an electronic component on a printed circuit board by a component mounting means that corrects the stroke according to the warpage, even if the printed circuit board has a wide variety of warpages locally. Therefore, the electronic component mounting method for mounting the electronic component on the printed circuit board is optimal.

The front view of the mounting line which enforces the mounting method of the electronic component which becomes embodiment of this invention The enlarged front view of the vicinity of the mounting head provided in the electronic component mounting apparatus according to the embodiment of the present invention The top view of the mounting apparatus of the electronic component which becomes embodiment of this invention The top view of the control means provided in the mounting apparatus of the electronic component which becomes embodiment of this invention Action explanatory drawing which shows the mounting method of the electronic component which becomes embodiment of this invention The flowchart which shows the mounting method of the electronic component which becomes embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mounting apparatus 4 Printed circuit board 5 Electronic component 13 Mounting head 15 Component mounting means 16 Component supply means 17 Height measuring means 18 Control means 18b Storage means B Component mounting position

Claims (3)

An electronic component mounting method for mounting an electronic component on a printed circuit board using a mounting device having a mounting head movable in the X-axis and Y-axis directions, wherein the print is positioned at a component mounting position of the mounting device. In order to measure the local warpage of the substrate, the height from the preset reference position to the printed circuit board was measured over a plurality of sets with a plurality of measurement points as a set, and obtained by the measurement. A step of averaging the measured values for each set and calculating a planar shape for each set; and a step of correcting a stroke of the component mounting means provided in the mounting head based on the planar shape data obtained by the calculation; And mounting the electronic component on the printed circuit board by the component mounting means whose stroke has been corrected. In measuring the local warpage of the printed circuit board, the printed circuit board is partitioned into a matrix, the corners of each cell are set as measurement points, and a plurality of the measurement points are set with the cell as a set. The method of mounting an electronic component according to claim 1, wherein a part is measured. A mounting apparatus comprising: a mounting head that is movable in the X-axis and Y-axis directions; and a component mounting means that is provided on the mounting head so as to be movable up and down, and that takes out an electronic component from a component supply means and mounts it on the printed circuit board. In order to measure the local warpage of the printed circuit board provided in the mounting head and positioned at the component mounting position of the mounting apparatus, the height from the preset reference position to the printed circuit board, A height measuring means that measures a plurality of sets with a plurality of measurement points as a set, and a measurement value obtained by the measurement is averaged for each set, and a planar shape is calculated for each set. An electronic component mounting apparatus comprising: control means for correcting a stroke of the component mounting means based on the obtained planar shape data.

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