JP7581564B2 - Component Mounting Equipment - Google Patents

Description

The present invention relates to a component mounting device that mounts components on a substrate.

A component mounting device that mounts components on a board includes a head unit having a head that mounts components, and a head movement mechanism that moves the head unit along the X-axis and Y-axis movement axes. The head movement mechanism moves the head unit so that a board is brought into the mounting stage of the device, a component is picked up from a component supply unit, and the component is mounted at a predetermined component mounting position. The component mounting position is identified in an axial coordinate system that is calibrated by capturing an image of a fiducial mark (hereinafter referred to as an FID mark) affixed to the board with a camera mounted on the head unit and recognizing the relative positional relationship between the board and the head.

Here, the XY movement axes expand and contract due to heat generated by the operation of the device. The axis coordinate system cannot be corrected to correspond to the thermal expansion and contraction of the XY movement axes by only recognizing the FID mark. For this reason, three or more calibration reference marks are placed on a base where thermal expansion and contraction can be ignored, and these are photographed by the camera. Then, the thermal displacement of the XY movement axes is measured by recognizing the reference marks, and the axis coordinate system is corrected so that the FID mark is correctly recognized (for example, Patent Document 1).

However, to capture images of the reference mark and FID mark, the head unit on which the camera is mounted must be moved along the X and Y axes. In other words, the head unit not only needs to move horizontally between the component supply position and the component mounting position, but also needs to move horizontally to capture images of the reference mark and FID mark. This is an obstacle to shortening the tact time for component mounting.

Patent No. 6678503

The object of the present invention is to provide a component mounting device that can perform correction of the axis coordinate system corresponding to the thermal expansion and contraction of the moving axis of the head unit while minimizing tactile loss as much as possible.

A component mounting device according to one aspect of the present invention comprises a base having a calibration reference mark attached thereto, a head unit having a head for mounting components on a board having a board recognition mark, a head movement mechanism for moving the head unit horizontally along a movement axis set on the base, a camera mounted on the head unit and capable of capturing images of the reference mark and the board recognition mark, and a control unit for controlling the imaging operation of the camera and for controlling the movement of the head unit based on a predetermined axis coordinate system. The control unit executes a first process in which the camera images the reference mark and the board recognition mark, and determines corrected mark coordinates, which are designated coordinates of the board recognition mark in the axial coordinate system calibrated by recognizing the reference mark, and determines a movement correction amount of the head unit based on the difference between the actual mark coordinates obtained by recognizing the board recognition mark and the corrected mark coordinates; and a second process in which the camera images the reference mark while omitting all or part of the imaging of the board recognition mark, and determines new corrected mark coordinates of the board recognition mark in the axial coordinate system calibrated by recognizing the reference mark, and calculates the position of the actual mark coordinates relative to the new corrected mark coordinates by referring to the positional relationship of the actual mark coordinates relative to the already obtained corrected mark coordinates, and determines the movement correction amount of the head unit based on the difference between the two.

FIG. 1 is a plan view that illustrates a schematic configuration of a component mounting apparatus according to a first embodiment of the present invention. FIG. 2 is a front view of a head unit provided in the component mounting apparatus. FIG. 3 is a block diagram showing the electrical configuration of the component mounting apparatus. FIG. 4 is a flowchart showing a correction process for the axis coordinate system of the movement axis in the component mounting apparatus of the first embodiment. FIG. 5 is a tabular diagram illustrating examples of correction modes. FIG. 6 is a plan view of a component mounting apparatus showing a modified example of the first embodiment. FIG. 7 is a plan view illustrating a component mounting apparatus according to the second embodiment. FIG. 8 is a flowchart showing a correction process for the axis coordinate system of the movement axis in the component mounting apparatus according to the second embodiment. FIG. 9 is a plan view illustrating a component mounting apparatus according to the third embodiment. FIG. 10 is a flowchart showing a correction process for the axis coordinate system of the movement axis in the component mounting apparatus according to the third embodiment.

[First embodiment]
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The component mounting apparatus described below is an apparatus for mounting electronic components onto a printed circuit board. The electronic components are, for example, chip components such as chip resistors and chip capacitors, ball bump components, and packaged components such as ICs.

<Overall structure of component mounting device>
FIG. 1 is a plan view showing a schematic configuration of a component mounting device 1, and FIG. 2 is a front view showing a schematic configuration of a head unit portion of the component mounting device 1. The component mounting device 1 is a device that produces a mounting board by mounting various electronic components on a board P. The component mounting device 1 includes a base 10, a board transport unit 2, a component supply unit 3 (component supply device), a head unit 4, a board recognition camera 5 (camera), and a multi-camera 11. In FIG. 1 and FIG. 2, directions of XYZ are indicated. In the following description, the X direction may be referred to as the left-right direction in which the board P moves, the Y direction as the front-rear direction, and the Z direction as the up-down direction.

The base 10 is a rectangular base with a flat top surface, and has a board transport unit 2 and a component supply unit 3 attached thereto. The board transport unit 2 transports the board P on which electronic components are mounted. The board transport unit 2 has a pair of conveyors 21, 22 that transport the board P in the left-right direction (X direction) on the base 10. The conveyors 21, 22 transport the board P from the right side into the component mounting device 1, transport it leftward to a predetermined work position, here the position of the board P shown in FIG. 1, and stop it once. At this work position, the electronic components are mounted on the board P. After the mounting work, the conveyors 21, 22 transport the board P leftward and out of the component mounting device 1.

The component supply units 3 supply electronic components 6 to be mounted on the board P. The component supply units 3 are arranged in the front-to-rear direction (Y direction) of the board transport unit 2. Each component supply unit 3 has a plurality of tape feeders 31 arranged in the left-to-right direction. Each tape feeder 31 holds a reel on which a tape is wound that contains electronic components such as chip components at predetermined intervals. The tape feeder 31 intermittently pays out tape from the reel and supplies chip components to the component supply position at the tip of the feeder.

The head unit 4 takes out electronic components from the component supply section 3 and mounts them on the substrate P. The head unit 4 is arranged to be movable along horizontal movement axes of XY set on the base 10, takes out electronic components from the tape feeder 31 at the component supply position, and mounts the electronic components at predetermined positions on the substrate P at the work position. A support beam 23 extending in the X direction is erected above the base 10. The head unit 4 is supported to be movable relative to an X-axis fixed rail 24 (movement axis) fixed to the support beam 23.

The support beam 23 is supported by a Y-axis fixed rail 25 extending in the Y direction, and is movable in the Y direction along this Y-axis fixed rail 25 (movement axis). An X-axis servo motor 26 and a ball screw shaft 27 are arranged relative to the X-axis fixed rail 24 as a head movement mechanism in the X direction. A Y-axis servo motor 28 and a ball screw shaft 29 are arranged relative to the Y-axis fixed rail 25 as a head movement mechanism in the Y direction. The head unit 4 moves in the X direction by the rotational drive of the ball screw shaft 27 by the X-axis servo motor 26, and moves in the Y direction by the rotational drive of the ball screw shaft 29 by the Y-axis servo motor 28.

The head unit 4 is equipped with multiple mounting heads 4H that mount components on the substrate P. Each head 4H includes a shaft 41 extending in the Z direction and a suction nozzle 42 attached to the lower end of the shaft 41. The shaft 41 can be raised and lowered relative to the head unit 4 and rotated around the nozzle central axis (R axis). The suction nozzle 42 is capable of suctioning and holding electronic components and mounting them on the surface of the substrate P.

The multi-camera 11 is built into the base. The multi-camera 11 is a camera with an imaging field of view above the base 10. The main role of the multi-camera 11 is to capture an image of the electronic component adsorbed by the suction nozzle 42 from the underside in order to image-recognize the state of the electronic component being adsorbed by the suction nozzle 42.

The board recognition camera 5 is mounted on the left side of the head unit 4. The board recognition camera 5 is a camera that images the top surface of the base 10 from above, and images various marks present on the top surface of the base 10. In Figure 1, the marks are exemplified by an FID mark FM (board recognition mark) attached to the surface of the substrate P, and calibration reference marks M1 to M3 installed on the top surface of the base 10.

The FID mark FM is a mark for detecting the amount of positional deviation from the origin coordinates of the work position of the loaded board P. The position of the FID mark FM is identified on the image data obtained by imaging with the board recognition camera 5, and the amount of positional deviation from the origin coordinates is determined. This amount of positional deviation is referenced when mounting components, and electronic components are mounted on the board P so that no positional deviation occurs.

The reference marks M1 to M3 are attached to a base 10 on which the influence of thermal expansion and contraction can be substantially ignored, and are calibration marks for measuring the degree of thermal displacement of the XY moving axes. In this embodiment, an example is shown in which two reference marks M1 and M2 are arranged at a distance in the X direction on the front side of the board transport unit 2, and one reference mark M3 is arranged on the rear side of the board transport unit 2. The XY moving axes, i.e., the X-axis fixed rail 24, the Y-axis fixed rail 25, and their ball screw shafts 27 and 29, etc., thermally expand due to heat generated by the operation of the component mounting device 1, such as frictional heat generated when the head unit 4 moves. When the XY moving axes thermally expand, an error occurs in the position accuracy of the head unit 4, and the mounting accuracy of the components decreases. The thermal displacement error can be calculated by imaging the reference marks M1 to M3, which do not undergo thermal displacement, with the board recognition camera 5 mounted on the head unit 4, which moves along the XY moving axes on which thermal displacement occurs. By controlling the movement of the head unit 4 so as to eliminate the obtained thermal displacement error, the deterioration of the mounting accuracy of the components is suppressed.

<Electrical Configuration of Component Mounting Device>
Next, the control configuration of the component mounting device 1 will be described. Fig. 3 is a block diagram showing the electrical configuration of the component mounting device 1. The component mounting device 1 includes a control device 7 (control unit) arranged inside or outside the base 10. The control device 7 controls the operation of each unit of the component mounting device 1 by executing a predetermined program. Note that the block diagram of Fig. 3 includes a Z-axis servo motor 43 and an R-axis servo motor 44, which are omitted in Figs. 1 and 2.

The Z-axis servo motor 43 and the R-axis servo motor 44 are motors built into the head unit 4. The Z-axis servo motor 43 is a drive source that raises and lowers the head 4H (shaft 41) along the Z axis when picking up or mounting electronic components. The R-axis servo motor 44 is a drive source that rotates the shaft 41 around the R axis.

The control device 7 functionally comprises an imaging control unit 71, an image processing unit 72, an axis control unit 73, a main control unit 74, and a memory unit 75. The imaging control unit 71 controls the imaging operation of the various cameras provided in the component mounting device 1, in addition to the board recognition camera 5 and the multi-camera 11. The imaging control unit 71 gives a control signal that specifies the timing for the board recognition camera 5 to image marks such as the reference marks M1 to M3 and the FID mark FM. When it takes a considerable amount of time to mount components on a single board P, the imaging control unit 71 causes the board recognition camera 5 to perform imaging operations of the marks multiple times during the mounting. This is to accommodate the possibility that changes may occur in the thermal displacement status of the XY movement axes during component mounting on a single board. As will be described in detail later, in this embodiment, in multiple mark imaging turns, the reference marks M1 to M3 are imaged, but the imaging of the FID mark FM is omitted, thereby preventing the tact time from becoming longer.

The image processing unit 72 applies image processing techniques such as edge detection processing and pattern recognition processing involving feature extraction to the image data acquired by the board recognition camera 5 and the multi-camera 11 to extract various information from the images. Specifically, the image processing unit 72 performs processing to identify the positions of the FID mark FM and the reference marks M1 to M3 based on the image data acquired by the board recognition camera 5. The image processing unit 72 also performs processing to identify the shape, position, etc. of the electronic component held by the suction nozzle 42 based on the image data acquired by the multi-camera 11.

The axis control unit 73 controls the movement of the head unit 4 in the X and Y directions by controlling the X-axis servo motor 26 and the Y-axis servo motor 28. The axis control unit 73 also controls the lifting and rotation of the mounting head 4H by controlling the Z-axis servo motor 43 and the R-axis servo motor 44 provided in the head unit 4.

The main control unit 74 comprehensively controls various operations for the component mounting device 1. For example, the main control unit 74 provides control signals to the imaging control unit 71, image processing unit 72, axis control unit 73, etc., to perform operations such as capturing an image, performing image processing on image data, and driving the head unit 4 and head 4H. The memory unit 75 stores various information related to the substrate P and electronic components, various setting values and parameters related to the component mounting device 1, control data, operation programs, etc.

The main control unit 74 functionally comprises a mounting control unit 741, a correction processing unit 742, and a correction mode setting unit 743 for controlling the movement of the head unit 4. The mounting control unit 741 identifies a position corresponding to a pre-specified component mounting position on the substrate P to be mounted based on an axial coordinate system based on the FID mark FM, and moves the head unit 4.

The correction processing unit 742 performs processing to determine a correction value for the movement amount of the head unit 4 in accordance with the thermal displacement of the XY movement axes described above. The correction processing unit 742 executes a first process and a second process as processing to determine the movement correction amount of the head unit 4. In the first process, both the reference marks M1 to M3 and the FID mark FM are imaged, and the movement correction amount is determined based on the recognition results of both marks. In the second process, only the reference marks M1 to M3 are imaged, the position corresponding to the FID mark FM is obtained by calculation, and the movement correction amount is determined.

The correction mode setting unit 743 sets the mode of the correction process for obtaining the movement correction amount of the head unit 4 and the frequency of execution of the correction process in response to an input instruction from the user. The correction process modes include a first mode in which the first process and the second process are executed, and a second mode in which only the process corresponding to the first process is executed. In component mounting on a large substrate P, multiple correction processes may be required during component mounting on one substrate P. In the first mode, among multiple correction process turns, in some turns, both the reference marks M1 to M3 and the FID mark FM are imaged and correction processes are performed, and in other turns, only the reference marks M1 to M3 are imaged and correction processes are performed. For example, only the first turn images both the reference marks M1 to M3 and the FID mark FM, and in the remaining turns, only the reference marks M1 to M3 are imaged. The second mode is a conventional correction process, in which both the reference marks M1 to M3 and the FID mark FM are imaged and correction processes are performed in each turn. The correction mode setting unit 743 appropriately switches between the first mode and the second mode to execute the correction process.

The thermal displacement state of the XY movement axes changes over time. For example, when the component mounting device 1 is first started operating, the degree of thermal expansion is large, and it is necessary to frequently calibrate the thermal displacement error using the reference marks M1 to M3. On the other hand, after a certain amount of time has passed since the start of operation, the thermal expansion saturates and the thermal displacement becomes small, so the frequency of the calibration can be reduced. In view of this, the correction mode setting unit 743 adjusts the frequency with which the correction processing unit 742 executes the correction processing. The correction mode setting unit 743 also adjusts the frequency with which the first processing is executed in the first mode.

<Details of correction process>
The correction process executed by the correction processing section 742 will now be described in detail. First, the head unit 4 is moved so as to pass successively above the reference marks M1, M2, and M3 on the base 10, and images of these reference marks M1 to M3 are acquired by the board recognition camera 5 under the control of the imaging control section 71. The acquired image data is sent to the image processing section 72, and the positions of the reference marks M1 to M3 are recognized. The thermal displacement of the XY movement axes generates a movement error of the head unit 4. The thermal displacement of the XY movement axes can be obtained based on this movement error. This thermal displacement A can be expressed by the following equation (1).

In the above formula (1), α, β, θ, and φ are parameters related to the thermal displacement of the X and Y movement axes. α is the elongation rate in the X-axis direction, β is the elongation rate in the Y-axis direction, θ is the amount of angular change in the X-axis direction, and φ is the amount of angular change in the Y-axis direction. Based on these parameters, the axial coordinate system of the X and Y movement axes is calibrated.

Next, the head unit 4 is moved so as to pass above the substrate P, and the substrate recognition camera 5 acquires images of the multiple FID marks FM attached to the substrate P. The acquired image data is sent to the image processing unit 72, and the position of the FID mark FM is recognized. The designated coordinates of the FID mark FM in the design of the substrate P brought into a predetermined working position of the component mounting device 1 are assumed to be _X0 , _Y0 as shown in the following formula (21). Also, the thermal displacement A of the XY moving axis measured before the first recognition of the FID mark FM, that is, the thermal displacement A in the first correction processing turn, is assumed to be as shown in the above formula (1). In this case, the corrected mark coordinates, which are the designated coordinates of the FID mark FM in the axis coordinate system after calibration at the time of the first turn, are as shown in the following formula (22). The actual mark coordinates, which are the coordinates of the FID mark FM obtained by the first recognition of the FID mark FM, are assumed to be _dX , _dY as shown in formula (23). The correction processing unit 742 calculates the movement correction amount of the head unit 4 based on the difference between the corrected mark coordinates _X0 , _Y0 after calibration and the actual mark coordinates _dX , _dY . Similarly, in the next correction processing turn, the corrected mark coordinates of the FID mark FM are calculated according to equation (24) using the thermal displacement A' of the XY movement axes obtained by recognizing the reference marks M1 to M3. It is assumed that the actual mark coordinates of the FID mark FM recognized in the current turn are _dX ', _dY ' as shown in equation (25). The correction processing unit 742 calculates the movement correction amount of the head unit 4 based on the difference between the corrected mark coordinates _X0 , _Y0 after calibration in the current turn and the actual mark coordinates _dX ', _dY '.

In the above-mentioned first process, in both the first and next correction process turns, the board recognition camera 5 is caused to capture the reference marks M1 to M3 and the FID mark FM (first imaging operation). That is, the actual mark coordinates of the FID mark FM shown in equations (23) and (25) are obtained by actually capturing an image of the FID mark FM using the board recognition camera 5. In contrast, in the above-mentioned second process, in the next correction process turn, the imaging of the FID mark FM is omitted and only the imaging of the reference marks M1 to M3 is performed (second imaging operation), and the actual mark coordinates corresponding to equation (25) are obtained by calculation with reference to the positional relationship of the initial actual mark coordinates (equation (23)) relative to the initial corrected mark coordinates (equation (22)) that have already been obtained.

上記式（３）より、次回ターンの実マーク座標ｄ_Ｘ´、ｄ_Ｙ´は、次の式（４）で算出することができる。

If the position of the substrate P is stationary, the actual position of the FID mark FM does not change between the first and next turn. Therefore, the positional relationship between the corrected mark coordinates _X0 , _Y0 after calibration in the first turn and the actual mark coordinates _dX , _dY is equal to the positional relationship between the corrected mark coordinates _X0 , _Y0 after calibration in the next turn and the actual mark coordinates _dX ', _dY '. Therefore, the actual mark coordinates _dX ', _dY ' for the next turn can be expressed by the following equation (3).

From the above formula (3), the actual mark coordinates _dX ', _dY ' of the next turn can be calculated by the following formula (4).

That is, since the coordinate values corresponding to the actual mark coordinates _dX ', _dY ' can be calculated by the calculation using the formula (4), it is not necessary to capture the FID mark FM in the next turn. In the second process, the correction processing unit 742 obtains the movement correction amount of the head unit 4 using the formula (4). In the second process, the reference marks M1 to M3 are also recognized, and the corrected mark coordinates of the FID mark FM in the calibrated axis coordinate system are obtained. Then, without capturing an image of the FID mark FM, the actual mark coordinates dX _' , _dY' are obtained by calculation using the formula (4) that utilizes the positional relationship between the corrected mark coordinates _X0 , _Y0 obtained in the first turn and the actual mark coordinates _dX , _dY . As a result, the tact time can be shortened by the amount of the omission of the image of the FID mark FM. Thereafter, the correction processing unit 742 obtains the movement correction amount of the head unit 4 based on the difference between the corrected mark coordinates X ₀ , Y ₀ calibrated in the current turn and the actual mark coordinates d _X ', d _Y '.

<XY movement axis correction process flow>
4 is a flowchart showing the correction process of the axis coordinate system of the XY movement axis in the component mounting device 1 of the first embodiment. Here, a case is assumed in which the correction process is performed multiple times during component mounting on one board P carried into the component mounting device 1. First, the correction mode setting unit 743 of the main control unit 74 sets an interval for performing the correction process to obtain a correction value of the movement amount of the head unit 4 corresponding to the thermal displacement of the XY movement axis (step S1). In the early period after the start of mounting operation of the component mounting device 1, the time change of the thermal displacement is relatively large, so the correction interval is set to a relatively short time (for example, about 1 minute).

Next, the correction mode setting unit 743 performs a correction mode setting process to determine in which correction mode the correction process is to be performed (step S2). In this embodiment, the correction modes provided are a tact-up mode that aims to improve the tact time by performing a combination of the first process and the second process described above, and a standard mode that performs only the process equivalent to the first process.

The correction processing unit 742 determines whether the correction interval set in step S1 has elapsed (step S3). In the first correction processing turn, the correction interval is set to 0, and the correction processing is executed immediately. When the correction interval has elapsed (YES in step S3), the correction processing unit 742 determines whether the currently set correction mode is the tact-up mode (step S4).

If the correction mode is the tact-up mode (YES in step S4), the correction processing unit 742 determines whether the image captured by the board recognition camera 5 in this correction processing turn is to capture both the reference marks M1 to M3 and the FID mark FM, that is, whether this is the execution turn of the first process described above (step S5). If it is the turn to capture both marks (YES in step S5), the correction processing unit 742 gives instructions to the image capture control unit 71 and the axis control unit 73 to have the board recognition camera 5 capture the reference marks M1, M2, and M3 in sequence, and then capture the FID mark FM of the board P (step S6). Usually, the first turn is set as the execution turn of the first process.

If it is not the turn to image both marks (NO in step S5), it is the turn to execute the second process described above, which images only the reference marks M1 to M3. The correction processing unit 742 causes the board recognition camera 5 to sequentially image the reference marks M1, M2, and M3 (step S7). For example, if the first process is executed on the first turn, the second process is executed on the following second to nth turns. Alternatively, the first process can be executed on every nth turn from the first, and the second process is executed on the remaining turns.

On the other hand, if the correction mode is not the tact-up mode (NO in step S4), the standard mode is set in step S2. In this case, the correction processing unit 742 causes the board recognition camera 5 to capture both the reference marks M1 to M3 and the FID mark FM in every correction processing turn (step S8). Although executing the standard mode worsens the tact time, it has the advantage that the component mounting device 1 can accurately derive the correction movement amount of the head unit 4 even if the fixed state of the loaded board P at the working position changes for some reason.

Then, the correction processing unit 742 determines the correction movement amount for the current turn based on the mark recognition result obtained in step S6, S7, or S8 (step S9). When the processing of steps S6 and S8 is performed, the correction processing unit 742 determines the correction movement amount of the head unit 4 based on the difference between the corrected mark coordinates of the FID mark FM calibrated by recognizing the reference marks M1 to M3 and the actual mark coordinates obtained by actual recognition of the FID mark FM. This corresponds to the first processing described above. On the other hand, when step S7 is performed, the correction processing unit 742 determines the correction movement amount of the head unit 4 based on the difference between the corrected mark coordinates and the coordinate values corresponding to the actual mark coordinates obtained by calculation using the above-mentioned formula (4).

Then, the main control unit 74 checks whether component mounting on the board P that was brought in this time has been completed, that is, whether the production of one board P has been completed (step S10). If production has been completed (YES in step S10), the current correction process is terminated. On the other hand, if production has not been completed (NO in step S10), the main control unit 74 checks whether an instruction to change the correction mode exists (step S11). If an instruction to change the correction mode exists (YES in step S11), the process returns to step S2, and the correction mode setting unit 743 sets the correction mode related to the change instruction.

Next, the main control unit 74 checks whether or not there is an instruction to change the interval between correction processing turns (step S12). If there is an instruction to change the correction interval (YES in step S12), the process returns to step S1, and the correction mode setting unit 743 changes the correction interval according to the change instruction. If there is no instruction to change the correction mode or the correction interval (NO in steps S11 and S12), the process returns to step S3 and is repeated.

Figure 5 is a tabular diagram showing examples of correction modes. Figure 5 describes the manner in which the reference marks M1-M3 and the FID mark FM are imaged in each mode. In the standard mode (second mode), the reference marks M1-M3 and the FID mark FM are imaged every time multiple correction processing turns are performed. In the tact-up mode (first mode), a turn in which both marks are imaged is combined with a turn in which only the reference marks M1-M3 are imaged.

In the tact-up mode, the modes are subdivided according to the frequency with which the FID mark FM is actually imaged. Execution frequency setting 1 is a setting in which one of five correction processing turns is a turn in which the reference marks M1 to M3 and the FID mark FM are imaged. In other words, one of five correction processing turns is a setting in which the above-mentioned first processing is performed, and the rest are a setting in which the second processing is performed. Execution frequency setting 2 is a setting in which one of ten correction processing turns is a setting in which the first processing is performed, and the rest are a setting in which the second processing is performed. Execution frequency setting 3 is a setting in which only the first correction processing turn is a setting in which the first processing is performed, and the rest are a setting in which the second processing is performed. In other words, by selecting one of execution frequency settings 1 to 3, it is possible to adjust the execution frequency of the first processing. By selecting the mode with execution frequency setting 3, the tact time can be shortened to the greatest extent. However, in the case of a substrate P in which the fixed state is expected to change after loading, it is desirable to select the mode with execution frequency setting 1 or 2.

<Modification of the First Embodiment>
In the above example, the board recognition camera 5 captures images of the reference marks M1 to M3 and the FID mark FM, and the movement correction amount of the head unit 4 relative to the board P is obtained. In addition, the movement correction amount of the head unit 4 relative to other elements provided in the component mounting device 1 may also be obtained.

Figure 6 is a plan view of a component mounting apparatus 100 according to a modified example of the first embodiment. The component mounting apparatus 100 includes a nozzle exchanger 12 arranged on a base 10. The nozzle exchanger 12 stocks suction nozzles 42 suitable for suctioning various components. When changing the type of substrate P to be produced, the head unit 4 is moved above the nozzle exchanger 12, and the suction nozzle 42 is replaced on the shaft 41. The nozzle exchanger 12 is provided with a nozzle exchange mark N1 that identifies the replacement position of the suction nozzle 42. By recognizing this nozzle exchange mark N1, the coordinate values of each suction nozzle 42 housed in the nozzle exchanger 12 are calibrated.

In addition, the tape feeders 31 of the component mounting device 100 are provided with feeder markers N2 that identify the component suction position by the suction nozzle 42. In Figure 6, only the six tape feeders 31 on the left side of the front row are shown with feeder markers N2, but in reality, the remaining tape feeders 31 also have feeder markers N2. By recognizing the feeder markers N2, the coordinate values of the component suction position of each tape feeder 31 are calibrated.

In such a component mounting device 100, in addition to the reference marks M1 to M3 and the FID mark FM, the nozzle replacement mark N1 and the feeder marker N2 are also captured by the board recognition camera 5. In other words, a correction process is performed for the axial coordinate system of the XY movement axes including the replacement position and the component suction position. The correction processing unit 742 executes the above-mentioned first and second processes based on the recognition results of the reference marks M1 to M3, the nozzle replacement mark N1, and the feeder marker N2, and determines the movement correction amount of the head unit 4 relative to the replacement position and the component suction position.

[Second embodiment]
In the second embodiment, an application example of the present invention to a so-called two-beam, two-head unit type component mounting device equipped with two XY movement axes and two head units is shown. Here, an example is given in which the mark recognition result by one head unit is applied to the correction process of the other head unit.

FIG. 7 is a plan view showing a schematic diagram of a component mounting apparatus 1A according to the second embodiment. The component mounting apparatus 1A has, as head units, a first head unit 4A on which a first board recognition camera 5A (first camera) is mounted, and a second head unit 4B on which a second board recognition camera 5B (second camera) is mounted. The first head unit 4A moves along a first X movement axis 61 and a first Y movement axis 62 (first movement axis), which are XY movement axes installed on a base 10. The second head unit 4B moves along a second X movement axis 63 and a second Y movement axis 64 (second movement axis). The first X movement axis 61 and the second X movement axis 63 are arranged in parallel with a predetermined interval in the Y direction, sandwiching a conveyor not shown in the figure. The first Y movement axis 62 and the second Y movement axis 64 are arranged in a pair on the left and right, and are adjacent to each other on the left and right.

The first head unit 4A has its movement in the X and Y directions controlled based on a predetermined first axis coordinate system. The second head unit 4B has its movement in the X and Y directions controlled based on a predetermined second axis coordinate system. Since the X and Y movement ranges of the first head unit 4A and the second head unit 4B are approximately the same, the first axis coordinate system and the second axis coordinate system can be treated as common coordinates. Even if both head units 4A and 4B have common coordinates, the X and Y movement axes are separate, so correction processing corresponding to thermal displacement must be performed for each X and Y movement axis.

In the conventional method, for each correction processing turn, the first board recognition camera 5A of the first head unit 4A captures the reference marks M1-M3 on the base 10 and the FID mark FM on the board P, and the second board recognition camera 5B of the second head unit 4B also captures the reference marks M1-M3 and the FID mark FM, and performs correction processing for each. However, since the two head units 4A and 4B each capture the FID mark FM, this consumes a considerable amount of time, and there may also be a wait time for capturing images to avoid interference between the two. This worsens the takt time.

To solve this problem, the correction processing unit 742 executes the correction processing of the second head unit 4B using the recognition result of the FID mark FM by the first board recognition camera 5A of the first head unit 4A. The correction processing unit 742 executes the processing equivalent to the above-mentioned first processing based on the image obtained by the imaging operation of the first board recognition camera 5A for the correction processing of the first axis coordinate system of the first head unit 4A. On the other hand, the correction processing unit 742 executes the processing equivalent to the above-mentioned second processing based on the image obtained by the imaging operation of the second board recognition camera 5B for the correction processing of the second axis coordinate system of the second head unit 4B. In other words, for the second head unit 4B, the positional relationship of the actual mark coordinates with respect to the corrected mark coordinates acquired by the imaging operation of the first board recognition camera 5A is converted to the second axis coordinate system to obtain the movement correction amount without causing the second board recognition camera 5B to perform the imaging operation of the FID mark FM.

8 is a flowchart showing the correction process of the XY movement axis in the component mounting device 1A of the second embodiment. The correction processing unit 742 causes the first board recognition camera 5A of the first head unit 4A to capture the reference marks M1 to M3 and recognize their positions (step S21). As a result, the thermal displacements shown in the above formula (1) are obtained for the first X movement axis 61 and the first Y movement axis 62, and the first axis coordinate system is calibrated. Similarly, the correction processing unit 742 causes the second board recognition camera 5B of the second head unit 4B to capture the reference marks M1 to M3 and recognize their positions (step S22). As a result, the thermal displacements for the second X movement axis 63 and the second Y movement axis 64 are obtained, and the second axis coordinate system is calibrated. That is, for the first and second axis coordinate systems, the corrected mark coordinates X ₀ and Y ₀ , which are the designated coordinates of the FID mark FM after the thermal displacement calibration, are obtained, respectively.

Next, the correction processing unit 742 causes the first substrate recognition camera 5A to capture images of all FID marks FM affixed to the substrate P and recognizes their positions (step S23). In the example of Fig. 7, two FID marks FM arranged on a diagonal line of the rectangular substrate P are captured by the first substrate recognition camera 5A. Based on the recognition result of the FID mark FM, the actual mark coordinates _dX , _dY of the FID mark FM are obtained. The correction processing unit 742 obtains a movement correction amount for the first head unit 4A based on the difference between the actual mark coordinates _dX , _dY and the corrected mark coordinates _X0 , _Y0 after calibration previously obtained in step S21 (step S24).

The correction processing unit 742 does not allow the second substrate recognition camera 5B to capture the FID mark FM. The FID mark FM is basically immobile until the production of one substrate P is completed. Therefore, if the relationship between the actual mark coordinates _dX , _dY of the FID mark FM and the corrected mark coordinates _X0 , _Y0 for the first head unit 4A is known, the relationship between the corrected mark coordinates _X0 , _Y0 of the second head unit 4B can also be obtained by axial coordinate conversion. That is, the position of the FID mark FM obtained by actual measurement of the first head unit 4A; the actual mark coordinates _dX , _dY are converted to the second axial coordinate system of the second head unit 4B and applied. This makes it possible to obtain the difference between the corrected mark coordinates _X0 , _Y0 and the actual mark coordinates _dX ', _dY ' of the second head unit 4B without actually measuring the FID mark FM with the second substrate recognition camera 5B. Therefore, the movement correction amount for the second head unit 4B can be obtained (step S25).

[Third embodiment]
In the third embodiment, an application example of the present invention to a two-beam, two-head unit type component mounting device equipped with two XY movement axes and two head units is also shown. Here, an example is given in which each head unit recognizes a part of a plurality of FID marks, and the FID mark recognition result of the head unit is applied to the correction process of the other head unit. That is, while the second embodiment shows an example in which the other head unit omits all imaging of the FID marks in the second process, the third embodiment shows an example in which the imaging of the FID marks is omitted.

Figure 9 is a plan view showing a schematic diagram of a component mounting apparatus 1B according to the third embodiment. The component mounting apparatus 1B includes a first mounting unit 40A having a mounting area on the mounting table A1 in the left half of the base 10, and a second mounting unit 40B having a mounting area on the mounting table A2 in the right half. The first mounting unit 40A is equipped with a first head unit 4C having a first board recognition camera 5C (first camera), and the second mounting unit 40B is equipped with a second head unit 4D having a second board recognition camera 5D (second camera).

The first head unit 4C moves along a first X movement axis 65 and a first Y movement axis 66 (first movement axis). The second head unit 4B moves along a second X movement axis 67 and a second Y movement axis 68 (second movement axis). The first X movement axis 65 is mounted on the first mounting unit 40A, and the second X movement axis 67 is mounted on the second mounting unit 40B. The first Y movement axis 66 is disposed on the left end side of the base 10, and the second Y movement axis 68 is disposed on the right end side of the base 10.

Three reference marks M11, M12, M13 are provided on mounting table A1 in the left half of base 10, and three reference marks M21, M22, M23 are provided on mounting table A2 in the right half. Substrate P is a large substrate that spans the left and right mounting tables A1 and A2, and is provided with a first FID mark FM1 (first substrate recognition mark) and a second FID mark FM2 (second substrate recognition mark). The first FID mark FM1 is a mark that is imaged by first substrate recognition camera 5C, and the second FID mark FM2 is a mark that is imaged by second substrate recognition camera 5D.

The correction processing unit 742 causes the first substrate recognition camera 5C to capture images of the reference marks M11, M12, M13 and the first FID mark FM1 for correction processing for the first axis coordinate system of the first head unit 4C. Also, the correction processing unit 742 causes the second substrate recognition camera 5D to capture images of the reference marks M21, M22, M23 and the second FID mark FM2 for correction processing for the second axis coordinate system of the second head unit 4D. The correction processing unit 742 executes processing equivalent to the first processing described above based on the images obtained by these imaging operations.

Furthermore, as a process equivalent to the second process described above, the correction processing unit 742 converts the position recognition result of the first FID mark FM1 by the first board recognition camera 5C into the second axis coordinate system, and converts the position recognition result of the second FID mark FM2 by the second board recognition camera 5D into the first axis coordinate system. This makes it possible to determine the movement correction amount of the two head units 4C, 4D without imaging the second FID mark FM2 with the first board recognition camera 5C, and without imaging the second FID mark FM2 with the second board recognition camera 5D.

Figure 10 is a flowchart showing the correction process of the XY movement axis in the component mounting device 1B of the third embodiment. The correction processing unit 742 causes the first board recognition camera 5C of the first head unit 4C to capture the reference marks M11, M12, and M13, and recognizes their positions (step S31). As a result, the thermal displacement for the first axis coordinate system consisting of the first X movement axis 65 and the first Y movement axis 66 is obtained, and the first axis coordinate system is calibrated.

Similarly, the correction processing unit 742 causes the second substrate recognition camera 5D of the second head unit 4D to capture images of the reference marks M21, M22, and M23, and recognizes their positions (step S32). As a result, the thermal displacement is obtained for the second axis coordinate system consisting of the second X movement axis 63 and the second Y movement axis 64, and the second axis coordinate system is calibrated. That is, for the first axis coordinate system, corrected mark coordinates _X0 , _Y0 , which are the designated coordinates of the first FID mark FM1 after the calibration of the thermal displacement, are obtained, and for the second axis coordinate system, corrected mark coordinates _X0 , _Y0 , which are the designated coordinates of the second FID mark FM2 after the calibration of the thermal displacement, are obtained.

Next, the correction processing unit 742 causes the first board recognition camera 5C to capture an image of the first FID mark FM1 and recognizes its position (step S33). Based on the recognition result of the first FID mark FM1, the actual mark coordinates _dX1 , _dY1 of the first FID mark FM1 are obtained. Furthermore, the correction processing unit 742 causes the second board recognition camera 5D to capture an image of the second FID mark FM2 and recognizes its position (step S34). Based on the recognition result of the second FID mark FM2, the actual mark coordinates _dX2 , _dY2 of the second FID mark FM2 are obtained.

Thereafter, the correction processing unit 742 converts the position of the second FID mark FM2 obtained by actual measurement of the second head unit 4D (actual mark coordinates _dX2 , _dY2) into the first axis coordinate system of the first head unit 4C and applies it. Using these actual mark coordinates _dX2 , _dY2 and the actual mark coordinates _dX1 , _dY1 obtained in step S33, the correction processing unit 742 obtains the movement correction amount of the first head unit 4C based on the difference between _these and the corrected mark coordinates _X0 , Y0 after calibration previously obtained in step S31 (step S35).

The correction processing unit 742 also converts the position of the first FID mark FM1 obtained by actual measurement of the first head unit 4C (actual mark coordinates _dX1 , _dY1) into the second axis coordinate system of the second head unit 4D and applies it. Using these actual mark coordinates _dX1 , _dY1 and the actual mark coordinates _dX2 , _dY2 obtained in step S34, the correction processing unit 742 obtains the movement correction amount of the second head unit 4D based on the difference between these and the corrected mark coordinates _X0 , _Y0 after calibration previously obtained in step S32 (step S36).

The component mounting device 1 may perform correction processing by combining the second and third embodiments described above depending on the layout of the head unit, the size of the board, and the arrangement position of the FID mark. That is, the board recognition camera of one head unit may capture all the FID marks, and the recognition results of the FID marks may be used in the correction processing of the other head unit, or the recognition results of some of the FID marks by each head unit may be used in the correction processing of the other head unit, depending on the board size and the FID mark position.

[Inventions included in the above embodiments]
The above-described embodiment includes the following inventions.

A component mounting device according to one aspect of the present invention comprises a base on which a calibration reference mark is attached, a head unit having a head for mounting components on a board having a board recognition mark, a head movement mechanism for moving the head unit horizontally along a movement axis set on the base, a camera mounted on the head unit and capable of capturing images of the reference mark and the board recognition mark, and a control unit for controlling the image capturing operation of the camera and controlling the movement of the head unit based on a predetermined axial coordinate system, and the control unit causes the camera to capture images of the reference mark and the board recognition mark, and captures images of the designated coordinates of the board recognition mark in the axial coordinate system calibrated by recognizing the reference mark. The method executes a first process of determining corrected mark coordinates and determining a movement correction amount of the head unit based on the difference between the corrected mark coordinates and the actual mark coordinates obtained by recognizing the board recognition mark; and a second process of having the camera capture an image of the reference mark while omitting all or part of the image of the board recognition mark, determining new corrected mark coordinates of the board recognition mark in the axial coordinate system calibrated by recognizing the reference mark, calculating the position of the actual mark coordinates relative to the new corrected mark coordinates by referring to the positional relationship of the actual mark coordinates relative to the corrected mark coordinates already obtained, and determining the movement correction amount of the head unit based on the difference between the two.

According to this component mounting device, in the correction process related to the first process, the camera actually captures the reference mark and the board recognition mark, and the corrected mark coordinates and the actual mark coordinates are obtained by recognizing these marks, and the movement correction amount of the head unit is calculated. On the other hand, in the second process, all or part of the imaging of the board recognition mark is omitted by referring to the positional relationship of the actual mark coordinates to the corrected mark coordinates that have already been obtained. The second process is, for example, a correction process performed on the same head unit after the first process (first embodiment), or a correction process on another head unit that has common coordinates with the head unit (second and third embodiments). Therefore, the takt time can be shortened by the amount that the imaging of the board recognition mark is omitted.

In the above-mentioned component mounting device, the control unit executes the first processing in a first imaging operation that is executed first, and executes the second processing in a second imaging operation that follows the first imaging operation, and the second processing may utilize the positional relationship of the actual mark coordinates relative to the corrected mark coordinates acquired in the first imaging operation.

With this component mounting device, when the first imaging operation for the first process and the second imaging operation for the second process are performed sequentially for the same head unit, the imaging of the board recognition mark can be omitted in the second imaging operation. Therefore, the tact time can be shortened in a component mounting device equipped with one head unit.

In the above-mentioned component mounting device, the head units include a first head unit equipped with a first camera and moving along a first movement axis, and a second head unit equipped with a second camera and moving along a second movement axis, and the control unit executes the first process based on an image obtained by the imaging operation of the first camera for correction processing for the first axis coordinate system of the first head unit, and executes the second process based on an image obtained by the imaging operation of the second camera for correction processing for the second axis coordinate system of the second head unit, and in the second process, the positional relationship of the actual mark coordinates relative to the corrected mark coordinates obtained by the imaging operation of the first camera is converted into the second axis coordinate system to obtain the amount of movement correction, without causing the second camera to perform an imaging operation of the board recognition mark.

With this component mounting device, when correction processing needs to be performed for each of the first and second head units, the imaging of the board recognition mark can be omitted in the imaging operation by the second camera of the second head unit. Therefore, for example, in a two-beam, two-head unit type component mounting device in which the two head units have the same mounting area, the tact time can be shortened.

In the above-mentioned component mounting device, the head unit includes a first head unit on which a first camera is mounted and which moves along a first movement axis, and a second head unit on which a second camera is mounted and which moves along a second movement axis, the board includes a first board recognition mark that is imaged by the first camera and a second board recognition mark that is imaged by the second camera, and the control unit causes the first camera to image the reference mark and the first board recognition mark for correction processing with respect to the first axis coordinate system of the first head unit, and causes the second camera to image the reference mark and the second board recognition mark for correction processing with respect to the second axis coordinate system of the second head unit. The substrate recognition mark may be imaged, and the first process may be executed based on the obtained images. In the second process for the second head unit, the positional relationship of the actual mark coordinates relative to the corrected mark coordinates used in the first process in the first axis coordinate system is converted into the second axis coordinate system to obtain the movement correction amount for the second axis coordinate system. In the second process for the first head unit, the positional relationship of the actual mark coordinates relative to the corrected mark coordinates used in the first process in the second axis coordinate system is converted into the first axis coordinate system to obtain the movement correction amount for the first axis coordinate system.

With this component mounting device, when correction processing needs to be performed for each of the first and second head units, it is possible to omit some of the imaging of the board recognition marks in each of the imaging operations by the first and second cameras. Therefore, for example, in a two-beam, two-head unit type component mounting device in which two head units are each responsible for a part of the mounting area, the tact time can be shortened.

In the above-mentioned component mounting device, it is desirable that the control unit performs at least imaging of the reference mark in the first process and imaging of the reference mark in the second process during component mounting on a single board.

It is assumed that the thermal displacement state of the moving axis will fluctuate during component mounting on a single board, and it is often necessary to perform correction processing of the moving axis multiple times. With the component mounting device described above, component mounting accuracy does not decrease even if the time required to mount components on a single board increases.

The above-mentioned component mounting device may further include a nozzle replacement mark that identifies the replacement position of the suction nozzle attached to the tip of the head, and a feeder marker that identifies the component suction position from a component supply device using the suction nozzle, and the control unit may cause the camera to capture an image of at least one of the nozzle replacement mark or the feeder marker, and perform the first process and the second process for an axial coordinate system including the replacement position and the component suction position based on the recognition result between the reference mark and the nozzle replacement mark or the feeder marker.

With this component mounting device, when the replacement position of the suction nozzle and the movement correction amount of the head unit relative to the component supply device are also determined, imaging of the nozzle replacement mark and feeder marker can be omitted in the imaging operation for the second process.

In the above-mentioned component mounting device, the control unit may be capable of switching between a first mode in which the first process and the second process are performed, and a second mode in which only a process corresponding to the first process is performed.

With this component mounting device, when the second mode is set, the first process is executed to capture images of both the reference mark and the board recognition mark. Therefore, even if the fixed state of the board is expected to fluctuate, the component mounting accuracy is not reduced.

In the above-mentioned component mounting device, it is desirable that the control unit is capable of adjusting the frequency of execution of the first process in the first mode.

With this component mounting device, the frequency with which the first process, which captures both the reference mark and the board recognition mark, is executed can be adjusted, allowing for more flexible response to fluctuations in the fixed state of the board.

The component mounting device of the present invention described above can perform corrections to the axis coordinate system corresponding to the thermal expansion and contraction of the moving axis of the head unit while minimizing tactile loss as much as possible.

Claims (8)

a base provided with a calibration reference mark;
a head unit including a head for mounting components on a board having a board recognition mark;
a head moving mechanism that moves the head unit in a horizontal direction along a movement axis set on the base;
a camera mounted on the head unit and capable of capturing images of the reference mark and the board recognition mark;
a control unit that controls the imaging operation of the camera and controls the movement of the head unit based on a predetermined axis coordinate system;
The control unit is
a first process of imaging the reference mark and the board recognition mark with the camera, determining corrected mark coordinates, which are designated coordinates of the board recognition mark in the axial coordinate system calibrated by recognizing the reference mark, and determining a movement correction amount of the head unit based on a difference between the actual mark coordinates obtained by recognizing the board recognition mark and the corrected mark coordinates;
a second process of causing the camera to capture an image of the reference mark while omitting all or part of the image of the board recognition mark, determining new corrected mark coordinates of the board recognition mark in the axial coordinate system calibrated by recognizing the reference mark, calculating the position of the actual mark coordinates relative to the new corrected mark coordinates by referring to the positional relationship of the actual mark coordinates relative to the corrected mark coordinates that have already been obtained, and determining a movement correction amount of the head unit based on the difference between the two. 2. The component mounting apparatus according to claim 1,
The control unit is
The first processing is executed in a first imaging operation that is executed first, and the second processing is executed in a second imaging operation that is executed after the first imaging operation,
A component mounting apparatus, wherein in the second processing, a positional relationship of the actual mark coordinates with respect to the corrected mark coordinates acquired in the first imaging operation is utilized. 2. The component mounting apparatus according to claim 1,
The head unit includes a first head unit having a first camera mounted thereon and moving along a first movement axis, and a second head unit having a second camera mounted thereon and moving along a second movement axis,
The control unit is
For correction processing for a first axis coordinate system of the first head unit, the first processing is executed based on an image obtained by an imaging operation of the first camera, and for correction processing for a second axis coordinate system of the second head unit, the second processing is executed based on an image obtained by an imaging operation of the second camera,
In the second process, the component mounting device converts the positional relationship of the actual mark coordinates relative to the corrected mark coordinates obtained by the imaging operation of the first camera into the second axis coordinate system to determine the movement correction amount without having the second camera perform an imaging operation of the board recognition mark. 2. The component mounting apparatus according to claim 1,
The head unit includes a first head unit having a first camera mounted thereon and moving along a first movement axis, and a second head unit having a second camera mounted thereon and moving along a second movement axis,
the substrate includes a first substrate recognition mark imaged by the first camera and a second substrate recognition mark imaged by the second camera,
The control unit is
for performing a correction process for a first axis coordinate system of the first head unit, cause the first camera to capture an image of the reference mark and the first substrate recognition mark, and for performing a correction process for a second axis coordinate system of the second head unit, cause the second camera to capture an image of the reference mark and the second substrate recognition mark, and perform the first process based on the obtained images;
In the second process for the second head unit, a positional relationship of the actual mark coordinates with respect to the corrected mark coordinates used in the first process in the first axis coordinate system is converted into the second axis coordinate system to obtain the movement correction amount for the second axis coordinate system;
A component mounting device that, in the second processing for the first head unit, converts the positional relationship of the actual mark coordinates relative to the corrected mark coordinates used in the first processing in the second axis coordinate system into the first axis coordinate system, thereby determining the movement correction amount for the first axis coordinate system. In the component mounting device according to any one of claims 1 to 4,
The control unit executes at least an image of the reference mark in the first process and an image of the reference mark in the second process during component mounting on one board. In the component mounting device according to any one of claims 1 to 5,
a nozzle replacement mark for identifying a replacement position of a suction nozzle attached to a tip of the head, and a feeder marker for identifying a component suction position from a component supply device by the suction nozzle,
The control unit causes the camera to capture an image of at least one of the nozzle replacement mark or the feeder marker,
a component mounting device that executes the first process and the second process for an axis coordinate system including the replacement position and the component suction position based on a recognition result of the reference mark and the nozzle replacement mark or the feeder marker. In the component mounting device according to any one of claims 1 to 6,
The component mounting apparatus, wherein the control unit is capable of switching between a first mode in which the first process and the second process are performed, and a second mode in which only a process corresponding to the first process is performed. 8. The component mounting apparatus according to claim 7,
The control unit is capable of adjusting a frequency of execution of the first process in the first mode.

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