JP2009070889A - Component mounting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a deterioration in mounting precision of a component due to size variation caused by temperature change of a circuit board during component mounting. <P>SOLUTION: The circuit board 1 is clamped by a clamp pin 14 on a support table during the component mounting. A temperature sensor 40 measures board temperature of the circuit board from below the circuit board without interrupting the component mounting halfway. A non-contact type temperature sensor is used as the temperature sensor 40 and can be freely arranged. A component mounting position is automatically corrected according to expansion or contraction of the circuit board due to change in board temperature. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a component mounting apparatus that sequentially picks up components and mounts them at corresponding positions on a circuit board, and in particular, reduces the mounting accuracy of components due to the expansion and contraction of the dimensions caused by the temperature change of the circuit board during component mounting. Suppresses the reduction in mounting accuracy due to the reduction of the circuit board when mounting components on the other side of the double-sided board that is thermally expanded after mounting and reflowing components on one side. It is related with the component mounting apparatus which can suppress the mounting precision fall which arises when the circuit board in which components are mounted is thermally expanded by heat_generation | fever.

  Conventionally, the core component of the component mounting device is thermally expanded due to the heat generated in the component mounting device, causing a reduction in mounting accuracy. Therefore, the offset amount of the misalignment due to the thermal expansion is obtained, and the mounting operation is stopped. Instead, the component mounting position is corrected based on the offset amount.

  For example, in Patent Document 1, before starting mounting on a circuit board, the temperature is measured for each basic component related to mounting accuracy, and an offset amount corresponding to the measured temperature is obtained. For example, as shown in FIG. 2, the temperature sensor 10 is attached to the suction nozzle 13 to measure the temperature, and the position of the suction nozzle 13 is corrected by the offset amount corresponding to the measured temperature.

  Further, in Patent Document 2, for example, as shown in FIG. 6, the light beams L and L ′ emitted downward from the light emitting unit 32 by the observation device 40 are caused by the inclination of the nozzle 24 due to the thermal deformation of the transfer head 22. It is made to grasp by observing the position of. Then, the movement stroke of the head unit 20 is corrected so as to correct the displacement amount of the positions of the light beams L and L ′, and the electronic component is mounted on the substrate. As a result, a decrease in mounting position accuracy due to the displacement of the lower end of the nozzle accompanying the temperature rise of the transfer head is suppressed.

Japanese Patent Laid-Open No. 11-186895 (FIG. 2) Japanese Patent Laid-Open No. 11-289198 (FIG. 6)

  However, since the conventional component mounting apparatus including Patent Document 1 and Patent Document 2 did not have a temperature correction function for the substrate mounted in the apparatus during component mounting, the expansion / contraction of the substrate due to the temperature change of the mounting substrate. As a result, there is a problem that the mounting position shifts. In particular, this problem is likely to occur when the number of mounting points is large and the mounting time is long.

  When the internal temperature of the component mounting apparatus is high, there is a problem that during the mounting time, the temperature of the substrate rises and thermal expansion occurs, and the mounting position of the component shifts. Alternatively, in the case of a double-sided board, after mounting and reflowing components on one side, the board whose temperature has been increased due to reflow and has been thermally expanded is boarded as the board temperature is lowered when components are subsequently mounted on the other side. However, there is a problem that the mounting accuracy of components is reduced.

  The thermal expansion coefficient of the circuit board varies depending on the substrate material such as an epoxy substrate or a glass substrate, but has not been considered in the past.

  The present invention has been made to solve the above-described conventional problems, and suppresses a decrease in mounting accuracy of a component due to expansion and contraction of a dimension caused by a temperature change of a circuit board during mounting of the component. After mounting and reflow, when mounting components on the other side of the thermally expanded double-sided board, it is possible to suppress a reduction in mounting accuracy due to the reduction of the circuit board. It is an object of the present invention to provide a component mounting apparatus that can suppress a decrease in mounting accuracy caused by thermal expansion.

  The present invention relates to a temperature sensor that measures the substrate temperature of a circuit board being mounted from the periphery of the circuit board in the component mounting apparatus that sequentially picks up the components and mounts them at the corresponding positions on the circuit board, and the board The above-described problem is solved by providing a control means for automatically correcting the component mounting position in accordance with the expansion and contraction of the circuit board due to the temperature change.

  In the component mounting apparatus, the board width set as a means for clamping the circuit board is automatically adjusted according to the expansion and contraction of the circuit board due to the change in the board temperature, thereby solving the above problem. is there.

  According to the present invention, it is possible to prevent a reduction in mounting accuracy even if the substrate is expanded or contracted due to temperature shift. Moreover, highly accurate correction can be performed by measuring the linear expansion coefficient of the substrate material. Furthermore, correction according to the linear expansion coefficient of the substrate material can be performed without stopping the mounting operation. Furthermore, even if the substrate expands or contracts due to temperature change, a stable substrate clamp state can be maintained by adjusting the substrate width.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view of a component mounting apparatus according to an embodiment to which the present invention is applied as viewed from the component feeder 37 side. FIG. 2 is a side view of the support table 10 of the component mounting apparatus as viewed from the component feeder 37 side. FIG. 3 is a plan view of the support table 10 as viewed from above.

  First, in FIG. 1, a head unit 20 to which a nozzle for adsorbing components to be mounted on the circuit board 1 and a Z-axis operation mechanism unit that moves the head unit 20 up and down are an X-axis gantry 30 and an X-axis motor 32. Is moved and positioned in the X-axis direction, and in the Y-axis direction by the Y-axis gantry 34 and 35 and a Y-axis linear motor (not shown).

  Further, the circuit board 1 carried in from the left by the conveying device 39 is clamped by the clamp pins 14 on the support table 10 during component mounting. In addition, the circuit board 1 on which all necessary components have been mounted in the component mounting apparatus is unloaded to the right by the transport device 39. In the transport device 39, the circuit board 1 is transported on the transport rail 12.

  Next, as shown in FIGS. 2 and 3, a temperature sensor 40 for measuring the substrate temperature on the back surface of the circuit board 1 is provided below the circuit board 1 to be clamped. In the present embodiment, the temperature sensor 40 is a non-contact type temperature sensor, but a contact type temperature sensor may be used. However, by using a non-contact type temperature sensor as the temperature sensor 40, the substrate temperature can be measured efficiently, and the degree of freedom of arrangement of the temperature sensor 40 itself is improved.

  Here, a part photographing camera 24 is provided in the movement range of the head unit 20, and the part photographing camera 24 photographs the part sucked by the suction nozzle of the head unit 20, and the position and inclination of the part are captured. Is supposed to be detected. The head unit 20 is provided with a BOC camera 22.

  FIG. 4 is a plan view showing an outline of the upper surface of the circuit board 1 on which components are mounted according to the present embodiment.

  As illustrated, BOC marks 5A to 5C, which are also referred to as substrate marks, are printed in the vicinity of three of the four corners of the circuit board 1. In a state where the circuit board 1 is clamped on the support table 10 of the component mounting apparatus, each of the BOC marks 5A to 5C is photographed by the BOC camera 22 by moving the head unit 20 above the BOC marks 5A to 5C. Based on the moving position of the head unit 20 and the imaging result, the control device 50 detects the positions of these BOC marks 5A to 5C when the clamped circuit board 1 is viewed from above. Further, the control device 50 detects the position, inclination, and expansion / contraction of the circuit board 1 when the clamped circuit board 1 is viewed from above based on the position detection of the BOC marks 5A to 5C.

  When the circuit board 1 extends due to the temperature change of the substrate temperature, the BOC mark 5B moves in the direction of the arrow A1 and the BOC mark 5C moves in the direction of the arrow A3 with reference to the BOC mark 5A. Alternatively, when the circuit board 1 contracts due to the temperature change of the substrate temperature, the BOC mark 5B moves in the direction of the arrow A2 and the BOC mark 5C moves in the direction of the arrow A4 with reference to the BOC mark 5A.

  If the linear expansion coefficient of the circuit board 1 is positive, the circuit board 1 expands as the substrate temperature increases, and the circuit board 1 contracts as the substrate temperature decreases. Alternatively, if the linear expansion coefficient is negative, the circuit board 1 contracts as the substrate temperature increases, and the circuit board 1 expands as the substrate temperature decreases.

  FIG. 5 is a block diagram showing a control configuration of the component mounting apparatus of the present embodiment.

  The control device 50 is read from an external storage device 56 to a RAM (Random Access Memory) 54 and controls the overall operation of the component mounting device by a software program executed by a CPU (Central Processing Unit) 52. It is.

  In this control, a temperature sensor signal input unit 66 for inputting a temperature detection signal from the temperature sensor 40, a nozzle control unit 68 for controlling the suction nozzle attached to the head unit 20, and a camera control for controlling the BOC camera 22. 70, a component recognition device control unit 72 that controls the component photographing camera 24, an XYZ axis movement mechanism control unit 76 that controls the XYZ axis movement mechanism of the head unit 20, and a component supply device control unit 78 that controls the component feeder 37. The substrate transfer device control unit 80 for controlling the transfer device 39 and the substrate clamp device control unit 82 for controlling the clamping / unclamping operation of the circuit board 1 related to the support table 10 are respectively connected via the I / O device 58. Thus, each corresponding part is controlled in cooperation with the control device 50.

  Note that the CPU 52, RAM 54, external storage device 56, and I / O device 58 are connected to each other via an internal bus 60.

  Hereinafter, the operation of the present embodiment will be described.

  FIG. 6 is a flowchart showing the operation of this embodiment.

  First, in step S <b> 110, the circuit board 1 is carried to the support table 10 by the transport device 39. In step S <b> 112, the loaded circuit board 1 is clamped on the support table 10 by raising the clamp pins 14. With this clamping, the circuit board 1 becomes ready for component mounting.

  In step S114, the controller 50 first captures the BOC marks 5A to 5C with the BOC camera 22 and recognizes the respective positions in order to grasp the position of the circuit board 1 when mounting the components. In step S116, based on the recognition result, the control device 50 detects the position, inclination, and expansion / contraction of the circuit board 1 when the clamped circuit board 1 is viewed from above.

  Subsequently, in step S118, the temperature sensor 40 measures the substrate temperature on the back surface of the circuit board 1 being clamped. Next, in step S50, it is determined whether all the component mounting on the circuit board 1 has been completed. If completed, the process proceeds to step 138. If the next process is acceptable, in step S138, the circuit board 1 on which component mounting is completed is carried out to the next process apparatus.

  Alternatively, if it is determined in step S50 that the operation is not completed, in step S122, the temperature sensor 40 measures the substrate temperature on the back surface of the circuit board 1 being clamped. In step S124, the presence / absence of temperature change is determined from the difference between the substrate temperature of the measurement result in step S122 and the reference substrate temperature (reference substrate temperature) measured in the past. This reference substrate temperature is the substrate temperature of the measurement result in step S118 described above.

  If it is determined that there is no temperature change, in step S126, the corresponding component is sucked by the suction nozzle, and the component is mounted at the corresponding mounting position on the circuit board 1. At the time of mounting, the mounting position is corrected based on the detection result of the position, inclination, and expansion / contraction of the circuit board 1 in the above-described step S114 and later-described step S132.

  Alternatively, if it is determined in step S124 that there is a temperature change, the process proceeds to step 132, and the position, inclination, and expansion / contraction of the circuit board 1 when the clamped circuit board 1 is viewed from above are newly detected. To do.

  Specifically, in step S132, the control device 50 photographs the BOC marks 5A to 5C with the BOC camera 22 and recognizes the positions of the BOC marks 5A to 5C in the same manner as in step S114 described above. Similar to step S116 described above, the control device 50 detects the position, inclination, and expansion / contraction of the circuit board 1 when the clamped circuit board 1 is viewed from above based on the recognition result. Further, for use in later processing after the detection, the control device 50 calculates the linear expansion coefficient of the circuit board 1 on which the current component is mounted from the amount of change in the substrate temperature and the amount of expansion / contraction of the circuit board 1. calculate.

  In the calculation, the amount of change in the substrate temperature is obtained from the difference between the current substrate temperature measurement result and the reference substrate temperature, and the amount of expansion / contraction of the circuit board 1 is determined based on the substrate temperature measurement result and the reference substrate temperature. It is obtained from the change in position of the BOC marks 5A to 5C recognized corresponding to the substrate temperature.

  Alternatively, in step S132, when the linear expansion coefficient of the circuit board 1 is obtained in advance in the control device 50, the position recognition of the BOC marks 5A to 5C is not performed as in step S114, and the control device 50 By calculating the current position of the BOC marks 5A to 5C by multiplying the difference between the substrate temperature measurement result this time and the reference substrate temperature by the linear expansion coefficient, the detected positions of the BOC marks 5A to 5C are calculated. Correct it. In step S132, the control device 50 determines the position of the circuit board 1 when the clamped circuit board 1 is viewed from above based on the respective positions of the BOC marks 5A to 5C as the calculation results. Detect tilt and expansion / contraction.

  As described above, when the linear expansion coefficient of the circuit board 1 is obtained, the operator may input the linear expansion coefficient of the circuit board 1 to be mounted in advance. Alternatively, since component mounting of the same circuit board 1 is continuously performed, the linear expansion coefficient of the circuit board 1 may already be calculated in the previous circuit board 1.

  In step S134, when the width of the circuit board 1 changes due to the change in the substrate temperature, the width of the conveyance rail 12 can be automatically adjusted or correctly clamped so that the circuit board 1 can be correctly conveyed and clamped. The position of the clamp pin 14 is automatically adjusted. After this step S134, the process branches again immediately before step S120.

  FIG. 7 is a flowchart showing the operation of a comparative example when the present invention is not applied in the present embodiment.

  When the present invention is not applied, after step S116, all necessary components are mounted on the circuit board 1 in steps S120 and S126, and after the mounting is completed, the circuit board 1 is unloaded in step S138.

  As described above, in the present embodiment, the temperature sensor 40 detects a change in the substrate temperature of the circuit board 1 without interrupting the mounting of components on the circuit board 1, and detects the detection positions of the BOC marks 5A to 5C. The component mounting position can be corrected in accordance with the board temperature change by correcting and correcting the position, inclination and expansion / contraction of the circuit board 1 being clamped.

  Further, since the width of the transport rail 12 is automatically adjusted or the position of the clamp pin 14 is automatically adjusted according to the change of the substrate temperature of the circuit board 1, the stable circuit board 1 is provided. Transport and clamping are possible. By securely clamping, it is possible to suppress warping of the circuit board 1 that is likely to occur due to temperature changes.

  Note that it is also conceivable that the component mounting position in the Z-axis direction on the circuit board 1 changes due to a warp caused by a change in the substrate temperature of the circuit board 1. In such a case, the change in the component mounting position in the Z-axis direction may be measured in step S132 described above, and the component mounting position in the Z-axis direction may be corrected in the subsequent component mounting in step S126. .

  In the present embodiment, an increase in the number of mounting points can be dealt with by using an X-axis motor 32 and a Y-axis linear motor (not shown) for driving the movement of the X-axis and the Y-axis, respectively. On the other hand, when a linear motor is used for moving the shaft, the heat generated by the motor tends to be trapped in the apparatus, and the temperature in the apparatus tends to rise. Therefore, the board temperature rises and changes during component mounting, and the circuit board 1 is likely to thermally expand. In particular, when the number of mounting points is large, the mounting time for mounting all necessary components on the circuit board 1 is prolonged, and the substrate temperature rises and the thermal expansion of the circuit board 1 is easy. In the present embodiment, such an adverse condition can be dealt with and the component mounting accuracy can be maintained.

  As a modification of the present embodiment, a contact temperature sensor may be used as the temperature sensor 40. Contact temperature sensors are usually less expensive than non-contact types. In this case, it takes time for the temperature detection portion of the contact-type temperature sensor 40 to be brought into contact with the circuit board 1 to adjust to the substrate temperature and to detect the substrate temperature with appropriate accuracy. For this reason, the board temperature of the circuit board 1 is measured in advance before the circuit board 1 is carried into the component mounting apparatus, and the board temperature is used instead of the board temperature measured in the above-described step S118. It may be. Also, the determination of the temperature transition in step S124 may be a determination that the temperature sensor 40 temporarily adjusts to the substrate temperature and that the process proceeds to step S132 temporarily without the temperature transition.

The perspective view which looked at the component mounting apparatus of embodiment with which this invention was applied from the component feeder side The side view which looked at the support table in the said embodiment from the parts feeder side The top view which looked at the support table in the said embodiment from upper direction The top view which shows the outline | summary of the upper surface of the circuit board which mounts components by the said embodiment. The block diagram which shows the control structure of the component mounting apparatus of the said embodiment. Flowchart showing the operation of the embodiment In the above embodiment, a flowchart showing the operation of a comparative example to which the present invention is not applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Circuit board 5A-5C ... BOC mark 10 ... Support table 12 ... Transfer rail 14 ... Clamp pin 20 ... Head part 22 ... BOC camera 24 ... Camera for part photography 30 ... X-axis gantry 32 ... X-axis motor 34, 35 ... Y-axis gantry 37 ... part feeder 39 ... conveying device 40 ... temperature sensor 50 ... control device 52 ... CPU
54 ... RAM
DESCRIPTION OF SYMBOLS 56 ... External storage device 60 ... Internal bus 66 ... Temperature sensor signal input part 68 ... Nozzle control part 70 ... Camera control part 72 ... Component recognition apparatus control part 76 ... XYZ axis movement mechanism control part 78 ... Component supply apparatus control part 80 ... Substrate transport device control unit 82 ... Substrate clamp device control unit

Claims (2)

In a component mounting device that picks up components sequentially and mounts them at the corresponding position on the circuit board.
A temperature sensor for measuring the substrate temperature of the circuit board being mounted from the periphery of the circuit board;
Control means for automatically correcting the component mounting position according to the expansion and contraction of the circuit board due to the change in the substrate temperature,
A component mounting device characterized by comprising:   2. The component mounting apparatus according to claim 1, wherein the board width set in the means for clamping the circuit board is automatically adjusted according to the expansion and contraction of the circuit board due to the change in the board temperature.

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