JP2576123B2 - Component mounting machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a component for mounting a component on a printed circuit board or the like by recognizing a lead of a point-symmetric component with a camera, correcting the mounting position with high accuracy. Related to mounting machines.

SUMMARY OF THE INVENTION The present invention is directed to a component mounter that corrects a mounting position and mounts a component. In a component mounter, a head unit for mounting / removing a mounted component having point-symmetric leads, a driving unit of the head unit, An image processing unit for recognizing a point-symmetric image of a lead, and a control unit for calculating a correction amount of a mounting position of the driving unit are provided. Determining the amount of displacement and correcting the mounting position based on the amount of displacement eliminates the need to align the coordinates of the camera and the driving means, thereby simplifying handling and enabling highly accurate correction of the mounting position. Thus, components can be mounted at accurate positions.

[Related Art] Conventionally, there has been known a component mounter that sucks a mounted component from a component supply unit to a head unit, positions the component on a printed circuit board, and mounts the component.

When performing the above mounting, there is an error in mechanical positioning, and there is a possibility that a component with a narrow lead pitch may cause mounting failure.Therefore, conventionally, errors in the mounting direction of the component and the suction position on the head part by the camera Was compared with the position in the normal case, the amount of deviation from the normal position was calculated, and the mounting position was corrected. For this reason, initially, it was necessary to match the origin and coordinate axes (Hoffset and Scale) of the camera's coordinate system and the head unit's coordinate system.

In addition, the head unit has a suction nozzle for attaching and detaching components, and the component is supplied in one direction, whereas mounting is supposed in all directions (up to four directions). Is configured to be rotatable around a rotation center. However, there is usually a slight error between the center of the nozzle and the center of rotation, and if the center of the nozzle is swung by rotation, the error in the mounting position increases as the lead pitch of the components becomes smaller. Therefore, conventionally, the nozzle is rotated by 90 ° in four directions, the center of the nozzle is image-recognized to obtain a rotation center, and the virtual center of the nozzle is used as the virtual center of the nozzle to perform image comparison of the above-described mounted components and correct the mounting position. Quantities were determined and corrected positioning was performed.

Further, conventionally, it has been necessary to previously store the reference position at the time of image comparison by teaching for each component mounting direction (a maximum of four sets with two leads as one set).

[Problems to be Solved by the Invention] However, the following problems have been encountered in the above-described conventional component mounter.

(1) The correction error at the time of alignment between the coordinate system of the camera and the coordinate system of the head unit and the error at the time of finding the virtual center of the nozzle of the head unit are compared with the correction amount of the mounting position of the component adsorbed on the nozzle. Therefore, there is a possibility that errors may be accumulated and the mounting position may be incorrectly corrected. On the other hand, in recent years, there has been a demand for a higher density of mounted components, and the lead pitch of the components has become increasingly finer, and it has been necessary to perform mounting with high precision positioning. .

(2) Various operations such as coordinate system adjustment between the camera and the head unit, determination of the virtual center of the nozzle, and teaching of the normal position of the component adsorbed to the nozzle must be performed in advance, and handling operations must be performed. It is troublesome.

(3) When performing image recognition of parts and nozzles, a camera light source is required to brightly illuminate the background of the recognition target. However, when performing image recognition at the center of the nozzle, the nozzle becomes obstructive and the camera light source is It cannot be located in the camera's field of view, which complicates the structure.

The present invention has been made in order to solve the above problems, and provides a component mounter that simplifies a handling operation and enables highly accurate correction of a mounting position when mounting components. Aim.

[Means for Solving the Problems] To achieve the above object, a component mounter according to the present invention has a configuration in which a head unit is attached to and detached from a component having leads at point-symmetric positions, and the head unit is mounted on the component. A drive unit that rotates in the point-symmetric direction before mounting, positions the head unit, and mounts the component, an image processing unit that includes a camera and recognizes an image of a lead of the component before and after the rotation, A control unit configured to calculate a correction amount of a component mounting position when positioning the head unit of the driving unit based on a shift amount between leads before and after the rotation recognized by the image. .

[Operation] According to the present invention, the head unit sucks a supply component having point-symmetric leads and moves to the position of the camera before mounting on a printed circuit board or the like, rotates the camera in the point-symmetric direction, and before and after the rotation. Then, image recognition is performed on the leads at the point-symmetric positions, and the shift amount between the leads is obtained. Since the shift amount includes an error of the rotation center of the head unit and a component suction error, the mounting position is corrected based on the shift amount. Therefore, it is not necessary to take in the image of the conventional suction nozzle for correcting the error of the rotation center, and it is also possible to make the coordinate adjustment of the camera unnecessary. Further, since the position correction of the suction component before mounting by image comparison is not performed, teaching at the reference position of the comparison image becomes unnecessary.

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

FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention. In this embodiment, a case where a flat package type IC (integrated circuit) having four-way leads is mounted on a printed circuit board will be described as an example.

Not surprisingly, the leads of this IC are point-symmetric. The mounting machine according to the present embodiment includes a board transport unit 1 that transports a printed board P and positions it at a mounting position, and a component (IC in the present embodiment) from a predetermined part cassette of a component supply unit (not shown).
3, a head unit 4 having a nozzle 4a for attaching and detaching the IC 3, and a nozzle 4a of the head unit 4.
Is rotated in the θ direction, and the head unit 4 is moved in three axial directions (X,
(Y, H), a control unit 6 for performing numerical control (NC) on the robot 5, an output control unit 7 for driving each unit based on an instruction from the control unit 6, and a camera 8. It is composed of an image processing section 9 which images the leads of the provided components, binarizes the image pickup signal and performs image recognition. The control unit 6 includes a CRT operation panel for initial settings and various operations. It is preferable that the head portion 4 includes a chuck 4b for mechanically roughly positioning the suction position of the sucked IC3.

Above the camera 8, a camera light source 10 is fixedly mounted, and an IC lead adsorbed to the nozzle 4a is positioned between the camera 8 and the camera light source 10 to perform image recognition. The positioning with respect to the camera 8 is performed in accordance with an instruction in the order stored in advance by the control unit 6. Is performed, and image recognition is performed. Subsequently, only the nozzle 4a is rotated by 180 °, the lead 3b of the IC 3 located at the symmetric position is positioned with respect to the camera 8, and image recognition is performed. At this time, the chuck 4b is in an open state when positioning with respect to the camera 8 because the chuck 4b interferes with image recognition and the camera light source 10. One lead position of the IC can be corrected from the above two images, and the rotation direction (θ direction) of the nozzle can be corrected from two points of one image. It is preferable to position the 3C with the camera 8 and perform image recognition to obtain the 3C in order to increase the accuracy when the field of view of the camera is narrow. The recognized image is displayed on the monitor TV 11, and can be observed,
It is sent to the control unit 6 for the correction operation of the mounting position. The camera light source 10 is configured by illuminating a translucent milky white plate with a light source from the back.

FIG. 2 is a flowchart showing the operation of the embodiment having the above configuration. First, the component suction operation will be described. First, the head unit 4 in the standby state is moved to the part cassette of the IC by “robot operation (on the part cassette)”, and “moving the feed unit” to the part cassette is performed. Subsequently, "vacuum ON" is performed to adsorb IC3 to the nozzle 4a, and "head DOWN" is performed in the H direction (vertical movement direction of the head), and IC3 of the parts cassette is adsorbed to the nozzle 4a of the head 4. I do. At this time, the chuck 4b is closed so that the IC 3 can be roughly positioned. The IC3 of the parts cassette is arranged on the tape, and the feed unit 2 separates the IC3 by "timing operation" and "separator ON". Next, "Head UP"
After that, the "separator is turned off", the feed unit 2 performs "component feed tape cutting", sends out the next component (IC3), and waits.

Next, the image recognition operation will be described. Nozzle 4a described above with IC
The head unit 4 in a state where 3 is sucked is moved closer to the camera 8 by “robot operation (close to the camera)”. Here, the chuck 4b is opened as “chuck ON”,
IC lead 3a by "robot operation (camera field of view)"
Is positioned at the imaging position between the camera 8 and the camera light source 10, and "image capture" is performed. Here, the image processing unit 9 determines whether the captured image is “normal”, and if the image is abnormal (NG), performs “warning light (patrol light) lighting” and terminates. wait. The above judgment is normal (O
In the case of K), the number of times of image capture is counted, and “3rd?” Is determined, and the second time following the first image capture,
The third image capture is performed. In the second image capturing, the nozzle 4a is rotated by 180 ° by “robot operation (camera field of view)” to perform “image capturing” of the lead 3b located symmetrically to the image of the first lead 3a. The third image capture,
By moving the IC 3 in the X direction or the Y direction (parallel to the mounting surface) in the “robot operation (field of view of the camera)”, the “image capture” of the lead 3b and another lead 3c of the same line is performed. When the third time is completed (YES), the “mounting (mounting) position correction calculation” is performed by the control unit 6 as described later.
The IC3 is pulled out toward the camera by "robot operation (before camera)", "head unit UP" is performed, and the image recognition operation is completed.

Next, the mounting (mounting) operation will be described. By the above-described mounting position correction, the error of the rotation center of the nozzle 4a and the error of the suction position of the IC3 are simultaneously corrected, and the "robot operation (on the mount)" allows the IC3 of the head unit 4 to accurately mount the printed circuit board P. Then, “head part DOWN” is performed, and IC3
Is placed in the mounting position, "vacuum OFF" is performed, suction of IC3 is released from nozzle 4a, "head unit UP" is performed, and the mounting operation is completed.

The mounting position correction calculation is performed as follows. First, a correction value (correction amount) of one point of the lead of IC3 is obtained.
FIG. 3 is an explanatory diagram thereof. A point in the image of the lead 3a is A, recognizes the coordinates (X _1, Y _1). Subsequently, the coordinates (X ₂ , Y ₂ ) of a point A ′ symmetric with A in the image of the lead 3b whose nozzle has been rotated by 180 ° are recognized. Assuming that the positioning of IC3 is performed by placing the rotation center of the nozzle at the center of symmetry of the lead of IC3, the virtual center is corrected by correcting the amount of deviation between A and A 'to be zero so that the virtual center is the center of symmetry of IC3. The error of the point A of the lead including the error of the rotation center of the head unit 4 and the error of the coarse positioning of the IC 3 by the chuck 4b can be corrected. That is, the correction values (X ₀ , Y ₀ ) Becomes

Next, a correction value (correction amount) θ ₀ of the rotation direction (θ) of IC3.
Ask for. FIG. 4 is an explanatory diagram thereof. The error of the rotation center and the suction error of the IC 3 are caused by the image capture of the lead 3c due to the movement of the head unit 4 from the image capture of the lead 3b. What is necessary is just to correct so that the inclination obtained from the deviation amount of B from the point A 'becomes zero. That is, the coordinates of the point B are represented by (X ₃ ,
Y ₃₎ to recognize, The correction value is used.

As described above, these correction amounts can be obtained from the deviation amounts of the two points of the recognized image.
If the calibration of the magnification of the robot and the coordinate system of the robot have been performed, it is not necessary to calibrate the absolute position of the camera 8 conventionally performed by the image recognition of the nozzle, and the coordinates of the camera coordinate system and the robot coordinate system are used. No alignment is required.

In the above mounting position correction, an image of the lead 3c is captured by moving the head part for correction in the θ direction, but this is because the camera raises the magnification to image a fine component, so that the field of view is reduced. If the camera has a wide field of view, correction can be performed by recognizing both point A or point A 'and point B in the first or second image capture. In addition, if the board transfer unit 1 can accurately align the printed board P with respect to the robot coordinate system, it is sufficient to correct only the above-described component side. to, for example, a camera mounted on the head portion 4 reads an alignment mark purine substrate P in this camera, the correction value X _P, Y _P, seek theta _P, the following formula was added to this correction value of the component side Then, the final correction value (X, Y, θ) may be obtained.

θ = θ _o + θ _p Note that the robot of the above embodiment is an example of the drive unit of the present invention, and the drive unit may be another dedicated mechanism such as a table mechanism as long as it can mount components. in this way,
The present invention can be variously applied according to the gist and can take embodiments.

[Effects of the Invention] As is clear from the above description, the component mounter of the present invention has the following effects.

(1) The relationship between the position of the nozzle rotating in the head unit and the camera coordinates is not input in advance, and only the image capture of the component is performed at once, including the rotation center error of the head unit and the suction error of the component of the head unit. Therefore, accurate component mounting can be performed without accumulating errors.

(2) Since there is no input of the relationship between the nozzle and the camera coordinates and no teaching of the comparative image of the parts, the handling operation is facilitated.

(3) Since there is no need to capture an image from the nozzle, the nozzle does not need to enter the field of view of the camera, and a camera light source (illumination device) can be arranged on the field of view of the camera, and the illumination device has a simple configuration.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention, FIG. 2 is a flowchart showing the operation of the embodiment, FIG. 3 is an explanatory diagram of correction of one point of the mounting position, and FIG. FIG. 4 is an explanatory diagram of rotation direction correction of FIG. 3 IC (parts), 3a, 3b, 3c, lead, 4 head part
5: robot (drive means), 6: control unit, 8: camera,
9 ... Image processing unit.

Claims (1)

(57) [Claims] 1. A head unit for mounting and dismounting a component having a lead at a point symmetric position, and rotating the head unit in the point symmetric direction before mounting the component, positioning the head unit, and mounting the component. An image processing unit having a camera and recognizing the lead of the component before and after the rotation; and a head of the drive unit based on the image-recognized displacement between the leads before and after the rotation. A component mounting machine, comprising: a control unit that calculates a correction amount of a component mounting position when positioning the unit.