JP2000307298A - Method of mounting part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To judge a part suction attitude by a suction nozzle in a part mounting device with high accuracy to suppress wrong judgement to the utmost. SOLUTION: In this method, an electronic part 50 is sucked by a suction nozzle 30, and then the electronic part 50 is photographed by an image pickup camera 110 to recognize the position of the electronic part 50 by image processing. Then, it is judged whether or not the sucked position of the electronic part 50 in the suction nozzle 30 is in its normal range, based on the recognized position. If the electronic part 50 has an external size within the normal range, it is judged to be good and is mounted at the predetermined position on an electronic circuit board 60. If the electronic part 50 has an external size without the normal range, it is judged to be no good and is discarded in the predetermined disposal position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a component mounting apparatus, which determines whether or not an electronic component suctioned by a suction nozzle is in a normal suction position, and determines only electronic components having a suction position within a normal range. The present invention relates to a method for mounting components at a predetermined position on an electronic circuit board.

[0002]

2. Description of the Related Art First, a general component mounting apparatus and its component mounting method will be described with reference to the drawings. FIG. 2 is a perspective view schematically showing a configuration of a main part of a general component mounting apparatus.
FIG. 3 is an enlarged perspective view showing the configuration of the moving head of the component mounting unit shown in FIG. 2, and FIG. 4 is a diagram showing suction of an electronic component sucked by a suction nozzle incorporated in the moving head shown in FIG. FIG. 5 is a perspective view showing a posture, and FIG. 5 is a perspective view showing a component suction state when an electronic component stored in a component supply cassette is suctioned by a suction nozzle.

First, a component mounting apparatus will be described with reference to FIGS. In FIG. 2, reference numeral 1 denotes a component mounting device. The component mounting apparatus 1 includes an XY robot 10 installed on a fixed base (not shown),
A moving head 20 moved by the robot 10,
A suction nozzle 30 (FIG. 3) mounted on the moving head 20 and sucking the electronic component 50 at a negative pressure or a vacuum pressure is used.
By sucking and holding the electronic component 50, the electronic component 50 is transported to a position above a predetermined mounting position on the electronic circuit board 60 that has been transported to a predetermined position by a transport device (not shown), and the electronic component 50 is released. It is mounted on the electronic circuit board 60.

The XY robot 10 has a pair of longitudinal guide members 12 and 14 arranged in parallel with each other at a predetermined interval on a fixed base and extending in the Y-axis direction. It is composed of a longitudinal guide member 16 disposed in a state of being moved, and a moving head 20 movably disposed on the longitudinal guide member 16. Then, although not shown, the feed mechanism transports the longitudinal guide member 16 in the Y-axis direction along the longitudinal guide members 12 and 14, and transports the moving head 20 in the X-axis direction along the longitudinal guide member 16. It is configured as follows.

The moving head 20 has a suction nozzle 30
Is provided in the H-axis (height) direction. This H-axis moving mechanism 80 is, for example, a nut in which a ball screw disposed on the moving head 20 is fixed to the support block 32 of the suction nozzle 30. The ball screw is driven by a control motor to move the suction nozzle 30 to the H position. This controls the movement in the axial direction. In addition, the moving head 20 is provided with an R-axis rotation mechanism 90 that rotates in a direction around the H-axis (R-axis direction).
Further, the moving head 20 is provided with an M-axis moving mechanism 100 that moves the light source unit 40 that illuminates the electronic component 50 held by the suction nozzle 30 in the M-axis direction.

As shown in FIG. 3, the light source unit 40 has a large number of light emitting diodes (LEDs) 44 disposed on a holder substrate 42 having an opening at the center. Is provided with a mirror 46. In the middle of the suction nozzle 30, the background plate 4
8 are provided. Light from each light emitting diode 44 is reflected by the electronic component 50 held by the suction nozzle 30 and guided to the mirror 46 through the opening of the holder substrate 42 as imaging light. The imaging light reflected by the mirror 46 is guided to the mirror 120 on the imaging camera 110 side, reflected by the mirror 120, and
Incident at 0. Furthermore, the imaging camera 110 and the mirror 120 are fixed to a predetermined position of the moving head 20, and take an image of the position of the electronic component 50 and perform a predetermined image processing, for example, by using the outer periphery of the electronic component 50. The suction position (posture) of the electronic component 50 is determined by recognizing the shapes of the electrodes and the like formed in the section.

The suction posture of the electronic component 50 by the suction nozzle 30 is always desired to be the suction state shown in FIG. 4A, but the suction posture sometimes includes the edge of the electronic component 50 as shown in FIG. 4B. 4C and 4D
As shown in (1), there is a case where the side surface and the end surface of the electronic component 50 are sucked. Such an abnormal suction posture is caused by the positional relationship between the suction nozzle 30 and the electronic component 50 in the component supply cassette 52 when the suction nozzle 30 performs suction of the electronic component 50 on the component supply cassette 52, and FIG.
In the case shown in FIG. 4, since the positional relationship between the suction nozzle 30 and the electronic component 50 is normal, the suction is performed in a normal posture as shown in FIG. 4A. For example, in the case shown in FIG. 5B or FIG. 4B, FIG. 4C, or FIG. 4D, the electronic component 50 thus attracted may be attached to the electronic circuit board 60. Since the posture of the electronic component 50 becomes inappropriate, electrical connection by soldering or the like cannot be performed satisfactorily, resulting in a defective board.

In recent years, the size of the electronic component 50 is extremely small, such as 1.0 mm × 0.5 mm × 0.3 mm, and the state as shown in FIG. 5B or FIG. This occurs due to variations in the processing and assembly accuracy of the cassette 52, vibration during machine operation, and the like. The electronic component 50 that has been sucked as shown in FIG. 4B, FIG. 4C, or FIG. 4D is discarded without being mounted on the electronic circuit board 60, and the same electronic component 50 is newly picked up from the component supply cassette 52. As a result, a recovery operation is performed.

[0009]

Conventionally, in order to determine whether or not the suction posture of the electronic component 50 is normal, a method of making a determination based on a value of a vacuum pressure sensor attached to a suction nozzle, an image processing method, and the like. Is determined by comparing the external dimensions of the electronic component obtained by the above with a fixed reference value. FIG. 4B shows the former method of making a determination based on the value of the vacuum pressure sensor attached to the suction nozzle.
Can be determined, but the suction abnormality as shown in FIGS. C and D cannot be detected. In addition, when sucking such a small electronic component as described above, the suction nozzle used has a small size corresponding to the size of the electronic component. Almost no pressure difference of the degree of vacuum from the case where it occurs is obtained.

The method of determining by comparing the external dimensions of the electronic component obtained by the latter image processing with a fixed reference value is based on the image of the electronic component 50 imaged by the imaging camera 110 shown in FIG. The external dimensions of the electronic component 50 obtained by image processing are used. The external dimensions obtained by the image recognition of the electronic component 50 are compared with the reference range at the time of normal suction, and if the external dimensions are out of the reference range, it is determined that the suction posture is defective. A problem at this time is that the reference range is a fixed value. When electronic components of the same standard are purchased from a large number of component manufacturers and mounted on an electronic circuit board, subtle differences in the shapes of the electronic components by the component manufacturers induce erroneous determination in normal suction determination.

The outer dimensions of the electronic component 50 by image processing also change depending on the brightness of the light source unit 40 illuminating the electronic component 50. Generally, when the light source is bright, the outer shape of the electronic component 50 is recognized as a large image, and when the light source is dark, the outer shape is recognized as a small image. Since the brightness of the light source is affected by the temperature, the brightness of the light source changes immediately after lighting and after a lapse of time, and also changes within one day due to the temperature. In addition, it also changes with time, and in the case of an LED, even if the LED is continuously lit at a constant temperature, it gradually darkens as it approaches the end of its life. Such a change in the brightness of the light source also induces an erroneous determination in the normal suction determination.

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problem, and it is possible to determine with a very high accuracy whether or not a component suction attitude by a suction nozzle in a component mounting apparatus is correct or not. It is an object of the present invention to obtain a component mounting method that can minimize erroneous determination.

[0013]

Therefore, according to the component mounting method of the present invention, the electronic component is sucked by the suction nozzle, the electronic component is imaged by a camera, and the electronic component is picked up by image processing. Recognizing the position, based on the recognized position, determining whether or not the suction posture of the electronic component with respect to the suction nozzle is normal, based on the external dimensions of the electronic component obtained by performing the image processing previously. Electronic components having external dimensions within the normal range are determined to be good, and are mounted at predetermined positions on the electronic circuit board. Electronic components having external dimensions outside the normal range are determined to be defective, and Without attaching to
The above problem is solved by adopting a method of disposing at a specific disposal position. In the component mounting method according to the second aspect of the present invention, in the component mounting method according to the first aspect, it is determined whether or not the suction posture of the electronic component with respect to the suction nozzle is normal. Among the external dimensions of electronic parts of the same shape that have been image-processed, the average dimensions and standard deviation are calculated by statistical processing from the external dimensions of the electronic parts judged to be normal, and the normal dimensions are determined to be within a constant multiple of the standard deviation from the average dimensions. To solve the above-mentioned problem.

Therefore, according to the component mounting method of the first aspect, the frequency of erroneous determination at the time of normal suction determination can be reduced. Further, according to the component mounting method of the present invention, the frequency of erroneous determination at the time of normal suction determination can be reduced, and further, it is possible to determine a subtle change in component dimensions due to a change in light source or a change in component manufacturer. The reference can be followed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A component mounting method according to an embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a flowchart of a component mounting method in the component mounting apparatus of the present invention.
First, the initial determination reference values X _min and X _max of the electronic component to be mounted on the electronic circuit board 60 are determined based on the reference dimensions of the electronic component of the component maker in the same manner as usual (step ST).
1) The information is recorded in a storage device of a computer provided in the component mounting apparatus 1. Next, the electronic components 50 to be mounted on the electronic circuit board 60 is adsorbed image processing by the suction nozzle 30, the outer dimensions Y ₁ is obtained (step ST2), the Y ₁ is X _min to X _max A check is performed in the computer to determine whether the area is within the range (step ST3). If Y ₁ is within the range of the X _min to X _max, it is determined to have been adsorbed in the normal position (step ST
4) If it is out of the above range, it is determined that it is sucked in an abnormal posture (step ST5). If it is determined that the adsorbed normal posture, the Y ₁ is recorded in the memory of the computer as Z _1.
Y if the Y ₁ are outside the scope of the X _min to X _max, which when it is determined that the abnormal posture adsorption, wherein Y ₁ is not recorded, it is determined that the adsorbed first normal position _i is recorded as Z ₁ (step ST6).

In this system, a constant m for determining how many times the statistical data should be used to update the criterion is set in advance.
Is set, and after the m-th record data Z _m is obtained, the past m record data Z _{j-m + 1} , Z _{j-m + 2} , Z
_{j−m + 3} ... The average value X _ave and the standard deviation X _stn of Z _j are calculated, and the next determination criteria X _min and X _max are redefined based on the calculated values (step ST7).

[0017]

(Equation 1)

[0018]

(Equation 2)

Note that in [Equation 1] and [Equation 2], k
Is a constant that determines how many times the standard deviation of the electronic component from the average value is considered normal. Usually m is 20 to 3
For 0 and k, values of about 3 to 6 are used. Also, the past m
Recorded data before the individual is unnecessary and is discarded.

In the above description, the measurement data Y has been treated and described as one piece of data. However, actually, in the case of a part having a complicated vertical or horizontal length or a complicated shape, In the method, the dimensions of other characteristic portions are used for the determination of the suction posture, and the method of the present invention can be similarly used for simultaneous determination of a plurality of locations.

As described above, the component mounting method of the present invention
Holds the external dimension data of the same type of electronic component that has been determined to be normal for the last m times during image processing, finds the average value and standard deviation, and sets the range up to k times the standard deviation from the average to the normal range. By doing so, the criterion can be made to follow a subtle change in component dimensions due to a change in the light source or a change in the component maker.

[0022]

As is apparent from the above description, the following effects can be obtained according to the component mounting method of the present invention.
That is, 1. By dynamically learning the suction position of electronic components using past measured values, even for electronic components of the same standard, dimensional changes due to differences in component manufacturers, dimensional changes due to differences in manufacturing lots, images It is possible to reduce influences such as fluctuations in measurement data due to changes in illumination luminance during measurement in processing. 2. As a result of the preceding paragraph, it is possible to avoid mounting the electronic components sucked in the abnormal posture on the electronic circuit board and to reduce the production yield of the electronic circuit board, and conversely, to remove the electronic components sucked in the suction posture. In addition, it is possible to suppress an increase in manufacturing cost due to discarding due to erroneous determination.

[Brief description of the drawings]

FIG. 1 is a flowchart of a component mounting method in a component mounting apparatus of the present invention.

FIG. 2 is a perspective view schematically showing a configuration of a main part of a general component mounting apparatus.

FIG. 3 is an enlarged perspective view showing a configuration of a moving head of a component mounting unit shown in FIG. 2;

4 is a perspective view showing a suction posture of an electronic component sucked by a suction nozzle incorporated in the moving head shown in FIG.

FIG. 5 is a perspective view illustrating a component suction state when an electronic component stored in a component supply cassette is suctioned by a suction nozzle.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Component mounting apparatus, 10 ... XY robot, 20 ... Moving head, 30 ... Suction nozzle, 40 ... Light source unit, 50 ...
Electronic components, 52: component supply cassette, 60: electronic circuit board, 110: imaging unit

Claims (2)

[Claims] An electronic component is sucked by a suction nozzle, the electronic component is imaged by a camera, the position of the electronic component is recognized by image processing, and the position of the electronic component with respect to the suction nozzle is determined based on the recognized position. Whether the suction posture is normal or not is determined based on the external dimensions of the electronic parts obtained by performing the image processing before, and the electronic parts having the external dimensions within the normal range are determined to be good, and the electronic circuit board is determined. The electronic component having an external dimension outside the normal range is determined to be defective, and is disposed at a specific disposal position without being mounted on the electronic circuit board. Component mounting method in the device. 2. In the component mounting method, in order to determine whether or not the suction posture of the electronic component with respect to the suction nozzle is normal, the external dimensions of the electronic components of the same shape that have been image-processed before are determined. 2. The component mounting method according to claim 1, wherein an average dimension and a standard deviation are determined by statistical processing from the external dimensions of the electronic component to be determined, and a normal within a constant multiple of the standard deviation from the average dimension is determined.