JP3273697B2 - Positioning method and device for mounting machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting machine for mounting an electronic component such as an IC on a printed circuit board by a movable head unit having a nozzle member for sucking the electronic component.
More particularly, the present invention relates to a position correcting method and apparatus for a mounting machine that performs a mounting operation in consideration of a movement error of a head unit.

[0002]

2. Description of the Related Art Conventionally, a small electronic component such as an electronic component such as an IC is sucked from a component supply unit by a component mounting head unit having a nozzle member and is placed on a printed circuit board positioned. 2. Description of the Related Art There is generally known a mounting machine for transferring and mounting at a predetermined position on a printed circuit board.
In this mounting machine, usually, the head unit is X
It can be moved in the Y plane and the suction nozzle
It is made movable and rotatable in the axial direction, a drive mechanism for movement and rotation in each direction is provided, and the negative pressure supply means and the drive mechanism for the nozzle member are collectively controlled by a control unit, Electronic components are automatically sucked and mounted.

As a mechanism for moving the head unit in the XY plane, a mechanism such as a rail mounted on a base is used.
A support member is movably mounted on the shaft, and a head unit is movably mounted on an X-axis such as a rail attached to the support member. A ball screw shaft rotated by a motor is mounted on the support member and the head unit. Is the mainstream. At the time of mounting, the head unit moves in the XY plane by moving the support member and the head unit along the X axis and the Y axis with the rotation of the ball screw shaft driven by the motor, respectively.

[0004]

As described above, in a mounting machine having a mechanism in which a support member or a head unit moves along a rail such as an X-axis or a Y-axis, the processing accuracy of the rail, the base of the rail, etc. Since the mounting accuracy of the rail directly affects the movement of the support member and the head unit, it is necessary to process these rails with high precision, or to mount and support the head member and the head unit along the rails. This is important for improving mounting accuracy.

[0005] However, there is naturally a limit in performing the processing of the rail and mounting it on a base or the like with high accuracy. Even if these operations are performed with high accuracy, in reality, rolling, Since yawing or pitching has occurred, it is difficult to precisely advance the support member and the head unit straight. Therefore, even if the electronic component is theoretically moved to the target position where the electronic component is to be mounted, a movement error often occurs in the head unit due to the above-mentioned physical factors in many cases. It is necessary to correct the set target movement position of the head unit, that is, a preset target mounting position of the electronic component.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problem, and it is possible to increase the mounting accuracy by performing a mounting operation in consideration of a movement error due to a physical factor such as rolling generated on a rail or the like. It is an object of the present invention to provide a position correction device for a mounting machine that can perform the correction.

[0007]

The invention according to claim 1 is
A mounting position correction method for a mounting machine for transferring and mounting electronic components on a component supply side to a printed circuit board in a mounting work position by an electronic component mounting head unit movably mounted above a base. A measurement board having a plurality of fiducial marks on its surface is arranged at the mounting work position, and according to the fiducial mark, the imaging means provided on the head unit is arranged at a predetermined imaging position with respect to the fiducial mark. The head unit is moved by the set amount, and each of the reference marks is imaged by the imaging means, and an error between the image position of the imaged reference mark and the appropriate image position of the reference mark to be imaged at the predetermined imaging position. And calculates the target of the electronic component based on the error data corresponding to a plurality of reference marks surrounding the target mounting position of the electronic component among the error data of each reference mark. It is intended to correct the wearing position.

According to a second aspect of the present invention, there is provided a head unit for mounting electronic components movably mounted above a base,
A drive unit for moving the head unit, wherein the head unit is configured to transfer the electronic component from the component supply side to the component mounting side. A measurement board that is arranged and has a plurality of fiducial marks on its surface,
Imaging means mounted on the head unit; drive control means for operating the driving means by a set amount corresponding to the reference mark so as to arrange the imaging means at a predetermined imaging position with respect to the reference mark; and Error calculating means for calculating an error between the image position of the reference mark actually captured by the imaging means when the driving means is operated and the appropriate image position of the reference mark to be captured at the predetermined imaging position; Storage means for storing error data obtained by the error calculation means; and error data corresponding to a plurality of reference marks surrounding the target mounting position of the electronic component among the error data of each reference mark are read out from the storage means. Correction means for correcting the target mounting position based on the data.

According to a third aspect of the present invention, in the position correcting apparatus for a mounting machine according to the second aspect, the measuring board is formed in the same shape as the mounting printed board, and the transfer means for transferring the mounted printed board. The reference marks are provided in a matrix at predetermined intervals on the surface of the measurement board.

[0010]

According to the position correcting method of the mounting machine of the first aspect, the mounting operation can be performed in consideration of the movement error of the head unit due to physical factors such as rolling generated on the rails. Specifically, assuming that the mounting printed board and the measurement board are superimposed, the mounting position of the electronic component is corrected based on error data for a plurality of reference marks surrounding the mounting position of the electronic component. .

According to the position correcting device for a mounting machine according to the second aspect, the image pickup means is arranged at a predetermined image pickup position by moving the head unit, so that the measuring board arranged on the component mounting side. Is taken. Then, an error between the proper image position of the reference mark to be originally picked up and the image position of the actually picked up reference mark is calculated, and based on the calculation result, the target mounting position of the electronic component, that is, the head unit at the time of mounting, Is corrected. The correction is performed based on error data for a plurality of reference marks surrounding the mounting position of the electronic component, assuming that the mounting printed board and the measurement board are overlapped.

According to the position correcting device of the mounting machine according to the third aspect, the plurality of reference marks on the measuring board arranged at the predetermined mounting operation position in the transporting means are sequentially imaged by the imaging means, so that the actual Each error between the captured image position of each reference mark and the appropriate image position for each reference mark is calculated.

[0013]

1 to 3 show a position correcting apparatus according to the present invention.
This will be described with reference to FIG.

FIGS. 1 and 2 show the overall structure of an electronic component mounter to which a position correcting device according to the present invention is applied, and FIG. 3 schematically shows a head unit to be described later.

As shown in these figures, on a base 1 of an electronic component mounting machine (hereinafter abbreviated as mounting machine), a conveyor (transporting means) 2 for transporting a printed board is arranged. Are conveyed on the conveyor 2 and stopped at a predetermined mounting operation position.

At the side of the conveyor 2, a component supply unit 4
Is arranged. The component supply unit 4 includes a plurality of rows of tape feeders 4a. Each of the tape feeders 4a stores and holds small pieces of electronic components such as ICs, transistors, and capacitors at predetermined intervals, and a tape is a reel. And a ratchet type feeding mechanism is provided at the tape feeding end, so that the tape is intermittently fed as electronic components are picked up by a head unit 5 described later.

Above the base 1, a head unit 5 for mounting components is provided. The head unit 5 is movable in an X-axis direction (the direction of the conveyor 2) and a Y-axis direction (a direction orthogonal to the X axis on a horizontal plane).

That is, a pair of fixed rails 7 extending in the Y-axis direction and a ball screw shaft 8 driven to rotate by a Y-axis servomotor 9 are disposed on the base 1. A head unit support member 11 is disposed on the support member 11, and a nut portion 12 provided on the support member 11 is screwed to the ball screw shaft 8. A guide member 13 extending in the X-axis direction and a ball screw shaft 14 driven by an X-axis servomotor 15 are disposed on the support member 11 so that the head unit 5 can move on the guide member 13. A nut portion (not shown) provided in the head unit 5 is screwed to the ball screw shaft 14. The ball screw shaft 8 is rotated by the operation of the Y-axis servo motor 9 to move the support member 11 in the Y-axis direction, and the ball screw shaft 14 is rotated by the operation of the X-axis servo motor 15, thereby causing the head unit to rotate. 5 moves in the X-axis direction with respect to the support member 11.

The Y-axis servomotor 9 and the X-axis servomotor 15 are provided with position detecting means 10 and 16 each comprising an encoder so that the operating position of the head unit 5 can be detected. Has become.

As shown in FIG. 3, the head unit 5 has first and second nozzle members 2 for adsorbing electronic components.
1 and 22 are provided. Both nozzle members 21 and 2
2 is Z with respect to the frame of the head unit 5.
Movement in the axial direction (vertical direction) and rotation about the R axis (nozzle center axis) are enabled, and are operated by Z axis servomotors 17 and 18 and R axis servomotors 19 and 20. Each of these servo motors 17 to 20 has
Position detecting means 21 to 24 each composed of an encoder are provided.
2 is detected. Also,
Each of the nozzle members 21 and 22 is connected to a negative pressure supply unit (not shown) via a valve or the like so that a negative pressure for component suction is supplied to the nozzle members 21 and 22 when necessary.

Further, a board recognition camera 25 is attached to the front side of the head unit 5. The board recognition camera (image pickup means) 25 picks up an image of a mark provided on the surface of the printed circuit board 3 at the time of mounting, and is attached to the measurement board 40 in a precision measurement process described below performed before the mounting operation. The reference mark 41 is imaged. At the front end (lower end) of the board recognition camera 25, a cylindrical light emitting body 26 composed of a large number of LEDs is provided.
Is fixed, and during imaging, an image is captured by the board recognition camera 25 via the detection hole 27 of the light emitting body 26 while emitting light from the light emitting body 26.

The measuring board 40 is formed, for example, in the same shape as the mounting printed circuit board 3, and a plurality (I) of reference marks 41 are arranged on the surface (upper surface) at a constant vertical and horizontal interval W. (In a matrix) (see FIG. 5).

Further, the base 1 is provided with a component recognition camera 28 for recognizing the suction state of the electronic components sucked by the head unit 5. The component recognition camera 28 is disposed on the side of the component supply unit 4. After the electronic components are sucked in the component supply unit 4, the head unit 5 moves to a predetermined position above the component recognition camera 28. By being caused to take place, the suction component is imaged.

Next, the control system of the mounting machine will be described with reference to the block diagram of FIG.

A control device 30 as shown in FIG. 4 is mounted on the mounting machine, and the Y-axis and X-axis servomotors 9 and 15 and the nozzle members 21 and 22 of the head unit 5 are mounted.
The Z-axis servomotors 17 and 18, the R-axis servomotors 19 and 20, and the position detecting means 10, 16, 21-24 for each servomotor are all provided by the control device 30.
Are electrically connected to each other, and are integrally controlled by the control device 30. More specifically, the main processing unit 3 provided with predetermined information for comprehensively controlling the operation of the mounting machine
2 and an axis control unit 31 controlled by the main arithmetic unit 32
Are provided in the control device 30, and the servo motor and the like are connected to the axis control unit 31 in the control device 30.

The axis control unit 31 and the main processing unit 32 perform control for performing a predetermined mounting operation at the time of mounting, and
In the accuracy measurement processing to be described later, the head unit 5 is moved by a set amount corresponding to each reference mark 41 so that the board recognition camera 25 is arranged at a predetermined imaging position with respect to each reference mark 41 on the measurement board 40. It functions as drive control means for causing the motor to operate.

An image processing unit 33 is connected to the main processing unit 32, and the board recognition camera 25 is connected to the image processing unit 33. The image processing section 33 is connected to an error calculating section (error calculating means) 34 connected to the main calculating section 32 and the storage section 35, respectively. It is connected.

That is, the image data captured by the board recognition camera 25 is subjected to predetermined image processing in the image processing unit 33, and then output to the main processing unit 32 and the image processing unit 33. .

In the image processing section 33, when the mark image attached to the printed board 3 is captured by the board recognition camera 25, the image data from the image processing section 33 is output to the main processing section 32, The main arithmetic unit 32 recognizes the mark.

On the other hand, when the image of the reference mark 41 on the measurement board 40 is captured by the board recognition camera 25, the image data from the image processing section 33 is output to the error calculation section 34. Then, the error calculating section 34 calculates the image center position of the reference mark 41 from the input image data, and calculates an error between the center position data and an appropriate data for the center position data. That is,
When the appropriate data is set as the origin on the XY plane (the intersection of the X axis and the Y axis), the amount of deviation between this origin and the image center position of the reference mark 41 is calculated. The error data for the mark 41 is stored in the storage unit 35. At the time of mounting, the error data stored in the storage unit 35 is read out to the main arithmetic unit 32,
Based on the error data, the target mounting position of the electronic component, in other words, the target moving position of the head unit 5 during mounting is corrected. That is, the main calculation unit 32 performs a function as a correction unit in addition to the function as the drive control unit described above.

Next, a position correcting method in the mounting machine will be described.

In the above-described mounting machine, before performing a predetermined mounting operation, the accuracy measuring process in the mounting machine is performed based on the flowchart shown in FIG.

In this process, first, as shown in FIG. 5, the measuring board 40 is fixed at a predetermined mounting work position at the time of mounting (step S1).

Next, after the initial value "1" is set to the counter value (step S2), the processing of steps S3 to S6 is repeated a number of times corresponding to the number of the reference marks 41. That is, by the movement of the head unit 5, the board recognition camera 25 is arranged above the predetermined I-th reference mark 41, and the I-th reference mark 41 is imaged by the board recognition camera 25 (step S3). , S4).

Next, the error calculator 3 of the control device 30
In 4, the error with respect to the reference mark 41, that is, the error between the image center position of the reference mark 41 and the proper image center position with respect to the image center position (errors Xi and Yi in the X-axis direction and the Y-axis method) is calculated. Then, the error data is stored in the storage unit 35, and thereafter, the counter is incremented (steps S5 and S6).

In step S7, it is determined whether or not the above-mentioned counter value has exceeded the total number of marks, that is, whether or not imaging of all the reference marks 41 attached to the measurement board 40 has been completed. Is NO, the process moves to step S3, the board recognition camera 25 is moved above the next reference mark 41 in a predetermined order, the image of the reference mark 41 is taken, and the error is calculated. . In this way, sampling of error data for each reference mark 41 is sequentially performed based on the imaging of each reference mark 41, and the error data and the position of each reference mark 41 are stored in the storage unit 35 as a table in association with each other.

When these processes are performed for all the reference marks 41 (YES in step S7),
The processing of the accuracy measurement according to this flowchart ends. After the completion of the processing, the measurement board 40 is removed from the mounting machine.

This processing is performed, for example, in the initial setting stage of the mounting machine, and is performed, if necessary, after an appropriate period during which the fixed rails 7 and the like may change with time.

When the accuracy measurement process is completed as described above,
A mounting operation for mounting electronic components is performed by the mounting machine.

First, when the mounting operation is started, the printed circuit board 3 is transported on the conveyor 2 and stopped at a predetermined mounting work position, and the head unit 5 is moved to the component supply unit 4 side. Then, a predetermined electronic component to be mounted is sucked by the nozzle member 21 or 22 and picked up from the component supply unit 4. When the electronic component is picked up in this way, the head unit 5 is moved to the side of the component supply unit 4 and the electronic component is arranged above the component recognition camera 28. Thereby, the image recognition of the electronic component is performed, and the nozzle member 21 or 22 is recognized.
Then, a correction amount for the suction displacement of the electronic component is calculated.

When the image recognition of the electronic component is completed, the head unit 5 is moved above the printed circuit board 3, and the electronic component is mounted at a predetermined mounting position on the printed circuit board 3.

In the mounting machine, when the head unit 5 is moved and the electronic component is mounted on the printed circuit board 3, a preset target mounting position of the electronic component, that is, a target moving position of the head unit 5, is set. ,
The head unit 5 is moved while correcting based on the error data obtained in the accuracy measurement process.

As an example of such a process for correcting the target movement position of the head unit 5, in the present embodiment, a process as shown in the flowchart of FIG. 7 is performed.

First, the target mounting position of the electronic component is compared with the position of each of the reference marks 41 stored in the storage unit 35, and the four reference marks 4 surrounding the target mounting position are compared.
1 is selected (steps S11 and S12). That is,
Assuming that the printed circuit board 3 is a measurement board 40, four reference marks 41 surrounding the target mounting position of the electronic component, for example, in FIG. The four reference marks 41 surrounding a to d are selected.

Then, as described above, the four fiducial marks 41
Is selected, error data for these reference marks 41 is read out, and a predetermined calculation process for position correction is performed based on the error data. After the target mounting position to be mounted is corrected (step S13), this flowchart ends.

When the above processing is completed, a drive signal corresponding to the corrected target mounting position is output to the motor, and the head unit 5 is moved. When the movement of the head unit 5 is completed, the nozzle member 21 or 22 is lowered to place the electronic component on the surface of the printed circuit board 3 and the supply of the negative pressure to the nozzle member 21 or 22 is cut off. Thus, the electronic component is mounted on the printed circuit board 3.

As described above, in the mounting machine of the above embodiment, before performing the mounting operation, each reference mark 41 written on the measurement board 40 is imaged using the board recognition camera 25, and thereby, Each reference mark 41 to be imaged
The accuracy measurement process of calculating and storing the error between the proper image center position and the image center position of each actually captured reference mark 41 is performed, and when actually performing the mounting operation, these error data are used. Based on this, mounting is performed while correcting the preset target mounting position of the electronic component, that is, the target moving position of the head unit 5, so that extremely high mounting accuracy can be secured. That is, even when physical factors such as rolling, yawing, and pitching that hinder the straight-moving performance of the support member 11 and the head unit 5 occur in the fixed rail 7 and the like, the head unit 5 and the like generated by these factors Since the head unit 5 and the like can be moved in consideration of the error at the time of the movement,
Unlike the conventional mounting machine, there is no possibility that the mounting accuracy of the mounting machine is reduced due to the above physical factors.

In the accuracy measurement process, the measurement board 40 is formed in the same shape as the printed board 3 and the measurement board 40 is arranged at the same mounting work position as the printed board 3 to obtain error data. So that
It is possible to obtain data that more closely approximates the movement error of the head unit 5 or the like that occurs during mounting. Further, in actual mounting, when the printed circuit board 3 is assumed to be the measurement board 40, the target mounting position is corrected based on error data for the four reference marks 41 surrounding the target mounting position of the electronic component. Thus, the target mounting position of the electronic component can be corrected based on a more accurate error corresponding to the tendency of the error generated near the mounting position of the electronic component. Therefore, in the mounting machine of the above embodiment, the target mounting position of the electronic component can be corrected with extremely high accuracy due to the synergistic effects.

The mounting machine of the above embodiment is an example of a mounting machine to which the position correcting device according to the present invention is applied.
The specific configuration can be appropriately changed without departing from the gist of the present invention.

For example, in the above embodiment, the board recognition camera 25 for picking up an image of a mark written on the printed board 3
Is used to take an image of the reference mark 41 of the measurement board 40, but only when assembling the mounting machine, such a recognition camera is attached to the head unit 5 to perform accuracy measurement processing. The obtained error data may be stored in advance as initial data, and the recognition camera may be removed at the stage of product shipment. This makes it possible to suitably correct the target mounting position of the electronic component at the time of mounting, even in a mounting machine that does not include the board recognition camera 25 for spec reasons.

Although the above embodiment does not particularly describe the handling of the target mounting position after correcting the target mounting position of the electronic component, for example, the target mounting position after the correction is updated. May be stored in the main processing unit 32.

Further, in the mounting machine of the above embodiment,
At the time of mounting, assuming that the printed circuit board 3 is the measurement board 40, the target mounting position of the electronic component is corrected based on the error data for the four reference marks 41 surrounding the target mounting position of the electronic component. However, this is one method for correcting the target mounting position. Needless to say, the error data for one reference mark 41 located near the target mounting position of the electronic component, or the error for the reference mark 41 which is higher than that of the embodiment. The target position may be corrected based on the data.

[0053]

As described above, according to the present invention, a plurality of fiducial marks on the measuring board placed at the mounting work position are imaged by the imaging means provided in the head unit, Calculate the error between the image position and the proper image position of the reference mark that should be taken,
Since the target mounting position of the electronic component, that is, the target moving position of the head unit at the time of mounting is corrected on the basis of the calculation result, a physical object such as rolling, yawing, or pitching that hinders the straight running performance of the support member or the head unit. Even if a general factor occurs on the rails, etc., the head unit can be moved by taking into account the error in moving the head unit caused by these factors, and as a result, high mounting accuracy is secured. can do. In particular, based on a comparison between the target mounting position of the electronic component and the reference mark position of the measurement board, the target mounting position of the electronic component is corrected from error data corresponding to a plurality of reference marks surrounding the target mounting position of the electronic component. In addition, it is possible to accurately correct the target mounting position according to the tendency of an error occurring near the mounting position of the electronic component.

In a specific configuration, the measuring board is formed in the same shape as the mounting printed board, and a plurality of fiducial marks are attached in a matrix on the surface thereof. If it is arranged at a predetermined mounting work position of the transporting means for transporting the substrate and the image of the fiducial mark is captured by the image capturing means, it is possible to obtain an error approximated by a movement error of the head unit or the like occurring at the time of mounting. Correction of the target mounting position can be performed more accurately.

[Brief description of the drawings]

FIG. 1 is a plan view showing a mounting machine to which an example of a position correction device according to the present invention is applied.

FIG. 2 is a front view showing a mounting machine to which an example of the position correction device according to the present invention is applied.

FIG. 3 is an enlarged view of a main part in FIG. 2 showing a head unit.

FIG. 4 is a functional block diagram showing a control system of the mounting machine.

FIG. 5 is a schematic diagram showing a state in which a measurement board is set on a conveyor.

FIG. 6 is a flowchart illustrating a process of accuracy measurement in the mounting machine.

FIG. 7 is a flowchart illustrating a process of correcting a target position in the mounting machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Conveyor 3 Printed circuit board 4 Component supply part 5 Head unit 7 Fixed rail 8,14 Ball screw shaft 9 Y-axis servomotor 10,16,21,22,23,24 Position detecting means 11 Support member 13 Guide member 15 X-axis servo motor 17,18 Z-axis servo motor 19,20 R-axis servo motor 21,22 Nozzle member 25 Board recognition camera 28 Component recognition camera 30 Controller 31 Axis controller 32 Main operation unit 33 Image processing unit 34 Error operation unit 35 storage unit 40 measurement board 41 fiducial mark

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G06T 1/00 G06T ⁷ /00-7/60 H05K 13/00-13/04 G01B 11/00-11 / 30 G01N 21/84-21/958

Claims (3)

(57) [Claims] 1. A movable equipped as a mounting position of the mounting machine for mounting and transferred to a printed circuit board with the electronic components of the component supply side to the mounting work position by the head unit of the electronic component mounted on the upper side of the base A correction method in which a measurement board having a plurality of reference marks on its surface is placed at the mounting work position.
And location, each reference mark set amount just by moving the head unit by the image pickup means in accordance with the reference mark as the imaging means provided in the head unit in a predetermined imaging position relative to standards mark is arranged the imaged, shooting calculates the error between the proper image position of the reference mark to be imaged in <br/> image image position and the predetermined imaging position of the reference mark, electrons of the error data of each reference mark parts
And correcting the target mounting position of the electronic component based on error data corresponding to a plurality of reference marks surrounding the target mounting position. 2. A head unit for mounting an electronic component movably mounted above a base, and a driving means for moving the head unit, wherein the head unit mounts the electronic component from a component supply side. A mounting board configured to be transferred to the side, a measuring board having a plurality of fiducial marks attached to a predetermined position on the component mounting side so as to be detachable and mounted on the head unit, Operating the driving means by a set amount according to the reference mark to dispose the imaging means at a predetermined imaging position with respect to the reference mark; and operating the driving means by the set amount. The image position of the reference mark actually captured by the imaging unit when the image is captured and the proper image position of the reference mark to be captured at the predetermined imaging position Error calculating means for calculating an error with respect to the position, storage means for storing error data obtained by the error calculating means, and
Multiple reference marks surrounding the target mounting position of
That the error data read from the memory means, the position correction device mounting apparatus, characterized in that a correction means for correcting the target mounting position on the basis of the error data. 3. The measuring board is formed in the same shape as the mounting printed board, and is arranged at a predetermined mounting work position of a transport means for transporting the mounting printed board , wherein the reference mark is 3. The position correcting device for a mounting machine according to claim 2, wherein the surface of the measuring board is provided in a matrix at predetermined intervals.