JP3788120B2 - Electronic component mounting method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component mounting method for mounting electronic components on a substrate.
[0002]
[Prior art]
The electronic component mounting apparatus includes a moving table for moving a transfer head that picks up an electronic component from an electronic component supply unit onto a substrate to be mounted. An orthogonal coordinate system table that performs linear motion in the XYZ directions is often used as the moving table. This moving table generally includes a substrate recognition camera that moves together with the transfer head, and detects the position of the substrate by imaging the substrate with this camera, and aligns the electronic component based on the position detection result. Is done.
[0003]
By the way, depending on the electronic component mounting apparatus, a plurality of moving tables may be provided for the purpose of improving mounting efficiency, and electronic components may be simultaneously mounted on a substrate on the same mounting stage using a plurality of transfer heads. is there. In such a mounting apparatus, a camera for board recognition is provided for each moving table, and before mounting electronic components, the board to be mounted is imaged and recognized by any of these cameras, Based on the obtained recognition result, each transfer head is moved to mount an electronic component.
[0004]
[Problems to be solved by the invention]
By the way, when mounting operations on the same substrate with a plurality of transfer heads that are moved by their own moving tables, the mounting load of each transfer head is not necessarily equal, and a larger mounting is performed by the transfer head on either side. A load may occur. However, in the above-described conventional method, the camera that performs board recognition among the plurality of cameras is specified by the initial setting, so that the mounting load by the transfer head on the board recognition side is larger than the mounting load on the opposite side. Even in this case, the moving table on the side where the mounting load is large must perform the moving operation including the board recognition operation. On the other hand, the moving table on the opposite side generates a wasteful waiting time. There was an imbalance in the tact time of the moving table. In this case, the longer takt time eventually becomes the takt time of the entire mounting operation, and as a result, the overall mounting efficiency is lowered and the improvement in productivity is hindered.
[0005]
Accordingly, an object of the present invention is to provide an electronic component mounting method capable of shortening tact time and improving productivity.
[0006]
[Means for Solving the Problems]
The electronic component mounting method according to claim 1 uses a plurality of moving tables each provided with a transfer head that picks up and transfers an electronic component and a substrate recognition camera that recognizes the substrate on which the electronic component is mounted. An electronic component mounting method for mounting an electronic component on a board, wherein a camera that actually performs a board recognition operation is determined from the plurality of cameras based on an operation load of each moving table.
[0007]
The electronic component mounting method according to claim 2 is the electronic component mounting method according to claim 1, wherein the operation load of each moving table is determined based on the mounting load for each transfer head of each moving table and the imaging of the substrate. It was calculated based on the substrate recognition operation load required for.
[0008]
According to the present invention, in the substrate recognition by the camera that is performed prior to the step of mounting the electronic component on the substrate by the plurality of transfer heads, it is actually selected from the plurality of cameras according to the operation load of the moving table that moves the camera. By determining the camera that executes the substrate recognition operation, the tact balance of each moving table can be maintained.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of an electronic component mounting apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a control system of the electronic component mounting apparatus, and FIG. 3 is a substrate recognition operation execution of the electronic component mounting apparatus. It is a figure which shows decision data.
[0010]
First, the structure of the electronic component mounting apparatus will be described with reference to FIG. In FIG. 1, a conveyance path 2 is provided on a base 1, and the conveyance path 2 conveys a substrate 3 carried in from a previous process and positions it at an electronic component mounting position. A first moving table 4A and a second moving table 4B having the same configuration are disposed on both sides of the transport path 2. The first moving table 4A and the second moving table 4B are configured by combining Y tables 5A and 5B and X tables 6A and 6B, respectively. The X tables 6A and 6B each include a first transfer head 7A. The second transfer head 7B is mounted. By driving the first moving table 4A and the second moving table 4B, the first transfer head 7A and the second transfer head 7B move horizontally, and electronic components are supplied from an electronic component supply unit (not shown). The pickup is picked up and mounted on the substrate 3 for mounting.
[0011]
The X tables 6A and 6B are equipped with a first camera 8A and a second camera 8B, respectively. The first camera 8A and the second camera 8B are respectively a first transfer head 7A and a second transfer head. It moves integrally with the mounting head 7B. The first moving table 4A and the second moving table 4B are driven to move the first camera 8A and the second camera 8B onto the substrate 3, and the recognition marks 3a provided at the respective diagonal positions of the substrate 3. Is captured by the first camera 8A and the second camera 8B, the position of the substrate 3 is recognized. Then, based on this position recognition result, a position shift of the substrate 3 is detected, and when the electronic component is mounted, the position shift is corrected and the first moving table 4A and the second moving table 4B are driven.
[0012]
Although an example in which the recognition mark is provided at each diagonal position of the substrate 3 is shown here, the position at which the recognition mark is provided is not limited to this, and a recognition mark is provided for each block set in the same substrate. There are several types, such as a case where a recognition mark is provided for each mounting point of an electronic component or an example where an identification mark is provided for each mounting point of an electronic component. In any case, these recognition marks need to be recognized prior to the mounting operation on the block or the mounting point.
[0013]
As described above, these recognition marks are picked up by either the first camera 8A or the second camera 8B, and their positions are recognized. Here, in order to prevent instrumental differences due to cameras, recognition points at the same position are imaged for each camera prior to actual recognition, and position teaching is performed to obtain an error for each camera in advance. In any case, the same recognition result can always be obtained regardless of which camera is used for imaging. This position teaching is performed by obtaining one of the reference marks MA and MB provided at a fixed position with the first camera 8A and the second camera 8B and obtaining offset data for each camera.
[0014]
Next, the configuration of the control system of the electronic component mounting apparatus will be described with reference to FIG. In FIG. 2, a control unit 20 is a CPU and controls the operation of the entire electronic component mounting apparatus. The program storage unit 21 stores programs necessary for various operations such as mounting operations. The mounting data storage unit 22 stores mounting data such as the type, mounting order, and mounting coordinates of electronic components mounted on the board 3. The mechanism control unit 23 performs drive control of the first moving table 4A, the second moving table 4B, the first transfer head 7A, and the second transfer head 7B.
[0015]
The recognition processing unit 24 recognizes the position of the recognition mark provided on the substrate 3 based on the image data of the substrate 3 captured by the first camera 8A and the second camera 8B. The operation / input unit 25 is a keyboard, a touch panel, or the like, and inputs control commands and data. The display unit 26 is a monitor, and displays an image captured by the first camera 8A and the second camera 8B and an operation screen. Based on the mounting data stored in the mounting data storage unit 22, the recognition operation execution determination unit 27 determines which of the first camera 8A and the second camera 8B is used to execute the board recognition operation. To do.
[0016]
Next, the recognition operation execution determination will be described with reference to FIG. FIG. 3 shows substrate recognition operation determination data, that is, operation loads generated on the first moving table 4A and the second moving table 4B for the same substrate. The operation load of the first moving table 4A is performed by using the total of the mounting loads Ai generated at each mounting turn (reciprocating movement of the transfer head between the substrate and the supply unit) and the first camera 8A. The total of the recognition operation load Di for board imaging is added together, and similarly, the operation load of the second moving table 4B is the board performed by using the total of the mounting load Bi and the second camera 8B. The sum of the recognition operation loads Ei for imaging is added.
[0017]
Here, the mounting loads Ai and Bi are represented by the distance that each transfer head 7A and 7B moves in each mounting turn, and can be calculated based on the mounting sequence in the mounting data. Note that a travel time calculated based on the travel distance instead of the travel distance may be used as a parameter representing the mounting load. The mounting load obtained in this way is not necessarily allocated equally to the first transfer head 7A and the second transfer head 7B, and generally there is an unbalance between the transfer heads. Arise.
[0018]
Therefore, in the recognition operation execution decision, the operation of recognizing the board in consideration of this imbalance is assigned to the cameras 8A and 8B provided in the respective movement tables 4A and 4B. Here, the recognition operation load is not inherently generated for each transfer head for each mounting turn unlike the mounting load, and a predetermined number of recognition points is determined in advance for the entire board. Given as a load.
[0019]
That is, in the recognition operation execution determination, the total load C of recognition operation given in advance as mounting data is allocated to two cameras. In this process, a newly generated movement distance is calculated by incorporating a recognition operation for imaging a target recognition mark into the operation sequence of each movement table, and this movement distance is obtained as a recognition operation load. As a result, the recognition operation loads Di and Ei are distributed to the first camera 8A and the second camera 8B, respectively. At this time, a load obtained by adding the sum of the mounting loads Ai and the sum of the recognition operation loads Di, that is, a load obtained by adding the operation load of the first moving table 4A, the sum of the mounting loads Bi, and the sum of the recognition operation loads Di. That is, the recognition operation load is distributed by repetitive calculation so that the operation load of the second moving table 4B is as uniform as possible.
[0020]
Note that when the recognition operation is distributed, the timing at which the recognition must be completed is specified in advance depending on the type of the recognition mark, and therefore the distribution is determined in consideration of these timings. For example, if it is a recognition mark for the entire board, the recognition operation must be performed in preference to all mounting operations, but as described above, a recognition mark is provided for each block set in the same board, Or when a recognition mark is provided for every mounting point of an electronic component, the recognition timing of these recognition marks should just be before the mounting operation to the said block or the said mounting point.
[0021]
The recognition operation execution determination described above is performed in advance by the recognition operation execution determination unit 27 based on the mounting data stored in the mounting data storage unit 22 prior to the start of the mounting operation. By causing each camera to perform the board recognition operation based on the recognition operation execution determination result obtained in this way, it is possible to correct the imbalance of the operation load between the movement tables. In the above example, the example of using the movement distance that each movement table actually moves as a parameter representing the mounting load or the recognition operation load is shown. However, in order to simplify the processing, the number of mounting turns is simply used as the mounting load. It is also possible to simply use the number of recognition points as the recognition operation load.
[0022]
Next, an electronic component mounting method will be described. First, prior to the actual mounting operation on the substrate, teaching is performed to correct the mounting position error by the first transfer head 7A and the second transfer head 7B. Here, as shown in FIG. 1, either the first camera 8A or the second camera 8B captures an image of one of the reference marks MA and MB set at a fixed point in the vicinity of the conveyance path 2, and the reference mark Is obtained and stored as offset data. Then, during the actual mounting operation on the board, position correction is performed based on these offset data. Thereby, even when the substrate is recognized by either the first camera 8A or the second camera 8B, the inherent error for each camera can be corrected by the offset data.
[0023]
In FIG. 1, the substrate 3 is carried in from the previous process and positioned at the electronic component mounting position on the conveyance path 2. Next, the first camera 8A selected as a recognition execution camera as a result of the recognition operation execution decision is positioned on the recognition mark 3a on the substrate 3, and the positions of the recognition marks 3a are sequentially recognized. Thereby, the position of the board | substrate 3 is recognized. Next, the first moving table 4A is driven to move the first transfer head 7A to a supply unit (not shown). After picking up electronic components there, the first transfer head 7A is moved again onto the substrate 3. Thus, the electronic component is mounted on the substrate 3.
[0024]
In this mounting operation, the first movement table 4A is driven while correcting the position error based on the position recognition result of the substrate 3 and the offset data specific to the first movement table 4A obtained by the above teaching.
[0025]
Thereafter, electronic components are mounted on the substrate 3 by the second transfer head 4B. At this time, the position recognition of the substrate 3 is not performed again, and the position error is similarly corrected using the position recognition result obtained by imaging by the first camera 8A and the offset data unique to the second moving table 4B. However, the second moving table 4B is driven.
[0026]
In this way, the electronic components are sequentially mounted on the substrate 3 using the plurality of transfer heads 4A and 4B. During this mounting operation, recognition marks provided on each block set on the substrate and recognition marks provided on each mounting point are recognized at a predetermined timing. In this position recognition, a camera that performs an imaging operation for substrate recognition is selected based on the above-described recognition operation execution determination result.
[0027]
This recognition operation execution decision is made after taking into account the operation load of the moving table that moves the camera to the recognition mark, that is, the operation load of each moving table during the mounting operation and the operation load during the recognition operation. The operation load is not concentrated on a specific moving table, and the operation state is not unbalanced. Therefore, it is possible to improve the efficiency of the entire mounting operation by eliminating the dead time in the mounting operation.
[0028]
【The invention's effect】
According to the present invention, in the substrate recognition by the camera that is performed prior to the step of mounting the electronic component on the substrate by the plurality of transfer heads, it is actually selected from the plurality of cameras according to the operation load of the moving table that moves the camera. Since the camera that performs the substrate recognition operation is determined, the tact balance can be maintained by equalizing the operation load of each moving table.
[Brief description of the drawings]
FIG. 1 is a plan view of an electronic component mounting apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing a configuration of a control system of the electronic component mounting apparatus according to an embodiment of the present invention. The figure which shows the board recognition operation execution decision data of the electronic component mounting apparatus of one embodiment of [Description of code]
3 Substrate 3a Recognition Mark 4A First Moving Table 4B Second Moving Table 7A First Transfer Head 7B Second Transfer Head 8A First Camera 8B Second Camera 22 Mounting Data Storage Unit 24 Recognition Processing Unit 27 Recognition action execution decision unit

Claims (2)

Mounting an electronic component on a substrate using a plurality of moving tables each equipped with a transfer head that picks up and transfers the electronic component and a substrate recognition camera that recognizes the substrate on which the electronic component is mounted A method of mounting an electronic component, comprising: determining a camera that actually performs a board recognition operation from the plurality of cameras based on an operation load of each moving table. 2. The electronic component mounting method according to claim 1, wherein the operation load of each moving table is obtained based on a mounting load for each transfer head of each moving table and a substrate recognition operation load required for imaging the substrate.

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