JPH0448248A - Cream solder printing and inspecting device - Google Patents

Abstract

PURPOSE:To eliminate the generation of defects and to improve a yield by analyzing the image data before parts are mounted on a circuit board printed with cream solder and deciding the normal/defective condition of the cream solder printing. CONSTITUTION:The images of the circuit patterns of the circuit board 12 are picked up by a TV camera 5 and the image data of the region of the circuit board 12 where the cream solder is presumed to be printed is taken into an image data analyzing section 7. The taken-in image data of the region of the circuit board 12 where the cream solder is presumed to be printed is investigated and the defect is detected from the degree of the presence or absence of the information indicating the presence of the circuit pattern therein. The ordinary operation to transfer the parts is started when the absence of the defect is decided. Then, the defective cream solder - printed circuit board having the high probability of generating the defect after the mounting of the parts is eliminated before the mounting of the parts and the high yield of production is maintained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an electronic component mounting device called a mounter, which automatically mounts electronic components onto a circuit board using a robot mechanism. Inspection of cream solder printing, which is particularly suitable for use in combination with electronic component mounting equipment that mounts surface-mounted electronic components such as ICs with a large number of leads on circuit boards with high-density circuit patterns. Regarding equipment.

[Conventional technology]

In recent years, electronic components such as ICs (hereinafter simply referred to as "components") have seen a remarkable increase in the number of leads and denser lead arrangement, and strict requirements have also been placed on improving the mounting positioning accuracy of electronic component mounting equipment using robot functions. is now given.

Reflecting this background, when mounting surface mount components, positioning marks and foot marks (# The pattern of the part where the leads of the product are soldered) and the lead position of the part held by suction to the movable member of the robot are captured as image data, and based on these data, the position of the circuit board and its circuit pattern is determined. , set the holding position of the part to v3#l,
A device that corrects the loading position based on this recognition result to ensure the required loading positioning accuracy has been proposed. You can see it.

By the way, in electronic component mounting equipment for surface-mounted components, it is necessary to apply cream solder to the foot marks on the board surface before mounting the component. In such an electronic component mounting device, a cream solder printing device is installed in the front process section.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, no particular consideration was given to the state of the board after cream solder printing, and the board that completed the cream solder printing process was directly sent to the next component mounting process, where components were mounted.

For this reason, with conventional technology, even if there is a misalignment between the foot pattern of the board and the printed position of cream solder, or if there is an excess or deficiency in the amount of printed cream solder, parts can be mounted through the reflow process. As a result, soldering can only be detected after processing has been completed, and as a result it appears as a defect, requiring a great deal of time and effort to correct the defect, or requiring the entire board on which the component is mounted to be discarded. There was a problem.

An object of the present invention is to provide a cream solder printing inspection device that eliminates the occurrence of defects due to the inadequacy of cream solder printing and sufficiently suppresses a decrease in the yield of electronic component mounting devices and product costs.

[Means for Solving the Problem] In order to achieve the above object, the present invention uses an imaging means,
This system captures image data from a board printed with cream solder before parts are mounted on it, and by analyzing this image data, it is possible to determine whether the cream solder printing is good or bad before parts are mounted.

To explain this in accordance with an embodiment of the present invention, according to an embodiment of the present invention, a television camera that images the board surface and a robot mechanism that moves the television camera to an arbitrary position on the board are provided. , the brightness data along a measurement line set in advance on the cream solder printed surface of the board is captured, and the difference in light reflectance between the cream solder applied area and the foot pattern exposed area is detected by the brightness change, and the cream solder is This allows the quality of printing to be determined before parts are mounted.

Further, according to another embodiment, depending on the result of the above-described pass/fail judgment, a board determined to be defective may be removed from the component mounting process, and the details of the defect may be displayed using a predetermined error message. This means that there is a means to do so.

According to yet another embodiment, the results of the quality determination described above are reflected in the printing position control in the cream solder printing process and the mounting position control in the component mounting process.

[Function] After the cream solder is printed on the board and before the components are mounted, it is determined based on the imaging results of the component mounting surface, so the printed state of the cream solder can be accurately grasped, and printing misalignment and application amount can be checked. Since quantitative detection including excess and deficiency becomes possible, highly reliable pass/fail judgments can be easily obtained.

[Example J] Hereinafter, the cream solder printing inspection apparatus according to the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 2 shows an embodiment in which the present invention is combined with an electronic component mounting device. In the figure, 1 represents the entire electronic component mounting device (mounter), 2 represents an orthogonal robot mechanism for mounting components, 3 is a board transfer unit, 4 is a component supply unit, 5.6
7 is a TV camera (television camera), 7 is an image data analysis section, 8 is a control section, and 9 is a mounter operation section.

The orthogonal robot mechanism 2 has a movable part that can move in the X and Y directions, and the head of this movable part has a suction nozzle that suctions parts and a mechanical centripetal claw that grips the suctioned parts, although not shown. The parts are moved and mounted using the equipment.

The board transport unit 3 functions to move a board on which no components are mounted to a mounting position, position it, and after mounting the components, send the board to a predetermined location as a mounted board.

The parts supply unit 4 sequentially supplies parts to be mounted from now on so that they can be easily picked up by the head of the orthogonal robot mechanism 2.
Works to prepare parts.

The TV camera 5 is attached to the movable part of the orthogonal robot mechanism 2 and takes an image of the board before parts are mounted, which is positioned at a predetermined position by the board transport part 3, and detects the circuit pattern (foot pattern) on the part mounting surface. It works to capture image data of both the circuit pattern of the board and the lead pattern of the component by capturing an image of the board again after mounting the component.

On the other hand, the TV camera 6 is installed facing upward on the top surface of the device, and since it will be mounted on the board from now on, the orthogonal robot mechanism 2
The device functions to take an image of the component suctioned by the head from below at a predetermined position and capture image data useful for confirming the suction position with respect to the head.

The image data analysis section 7 analyzes image data from the TV camera 5.6 and executes predetermined data processing, and details of its operation will be described later.

The control unit 8 controls the entire device necessary for mounting components, including the operations of the orthogonal robot mechanism 2 and the substrate transport unit 3 described above.

The mounter operation section 9 includes switches necessary for operations such as starting and stopping the operation of the apparatus, and a display necessary for monitoring the operation.

FIG. 3 shows an enlarged image of the board taken by the TV camera 5, in which 1o is a suction nozzle for vacuum-chucking electronic components, 11 is the head of the robot, and 12 is the board transfer unit 3. This is the board that has been transported to the imaging position by the camera.

The above configuration is necessary in common with electronic component mounting devices, but in this embodiment, a board ejecting device 13, a defective board stocker 14, and an interface cable 15 are further provided.

First, the board discharging device 13 takes out the boards determined to be defective in cream solder printing from the board transport section 3 and stores them in the defective board stocker 14 in a predetermined order.

Further, the interface cable 15 is connected to a cream solder printing device (not shown), and transmits data necessary for controlling the delivery and reception of printed boards from the cream solder printing device and emergency stop control, and data representing the cream solder printing state. work to do.

Next, the operation of this embodiment will be explained using a flowchart showing the processing procedure shown in FIG.

Here, 81 to S13 in FIG. 1 represent processing steps.

First, as shown in the third rgJ, the board 12 printed with cream solder in the previous step is carried in by the board transport section 3 and mechanically positioned at a predetermined position (Sl).

Next, move the head part 11 of the orthogonal robot mechanism 2,
The positioned substrate 12 is brought into the field of view of the TV camera 5 (S2).

The circuit pattern (foot pattern) of the board 12 is imaged by the TV camera 5, and the image data analysis unit 7 images the circuit pattern (foot pattern) of the board 12.
The exact position of the predetermined pattern is detected (S3).

The above is the same operation as an electronic component mounting device.
Below, (S4), (S5), and (S10) to (S1
The operation 3) is added in the embodiment of the present invention.

First, the image data of the area on the board 12 where the cream solder is likely to be printed is taken into the image data analysis section 7 using the TV camera 5 (S4).

Next, the image data of the area where cream solder is likely to be printed on the board 12 that has been imported is examined, and defects are detected based on the degree of presence or absence of information indicating the existence of a circuit pattern (foot pattern). (S
S).

When it is determined that there is no defect, the normal component mounting operation is started. First, the head section 11 is moved above the component supply section 4, and the suction nozzle 10 is used to remove components such as ICs.
is adsorbed and held (S6).

Next, while holding the component in the head section 11, it is moved over the TV left camera, the component is imaged, and the image data analysis section 7
The position of the lead pattern of the component is recognized by the head part 11.
The positional deviation between the component and the component is corrected and the component is mounted on the board 12 (S7).

Note that at this time, the processes of (S8 and (S9)) may be executed as necessary.

On the other hand, when the determination result in (S5) is that there is a defect, the process moves to defect processing operations (510) to (S13).

Here, an example of the detection and determination of print defect content in (S5) will be described with reference to FIGS. 4 (!1 to 7).

First, as shown in FIG. 4(A), two pixel data acquisition lines A and B are set for an image of a foot pattern F on which cream solder is to be printed.

In this embodiment, the number of wires is two, but it goes without saying that a larger number of wires may be set as required.

Next, if we look at the brightness of pixels that exist along one of these pixel data acquisition lines A and B, for example along line A, in this case, as shown in the same figure (b), Indicates a certain level.

This is this j! ! As shown in Figure 4 (a),
This is because the cream solder S is printed correctly on the foot pattern F, and the reflectance of the fabric surface of the board 12 and the reflectance of the cream solder S are almost equal.

On the other hand, IF! As shown in Figure 5 (A), when the cream solder S is not printed at the correct position with respect to the foot pattern F, the brightness along the pixel data acquisition line will change as shown in Figure 5 (G). At the level of , maximum portions X1, X appear in the exposed portion of the foot pattern F.

This is because the reflectance of the foot pattern F is considerably higher than both the reflectance of the fabric surface of the substrate 12 and the reflectance of the cream solder S.

Similarly, if the amount of cream solder S is insufficient, the results will be as shown in Figures 6 (a) and (b), and the printed state of cream solder S will be different from that in Figure 5. , if a shift due to inclination has occurred, Fig. 7 (a),
As in (b), each becomes different.

Therefore, returning to FIG. 1, in the printing defect detection judgment at (S5), a predetermined judgment reference level is set for the brightness of the pixel data from these pixel data capture MA and B, and the captured pixel data is It is determined that cream solder printing is defective depending on whether portions exceeding this determination reference level, for example maximum portions X1, x4, X, Xl, appear.

In addition, at this time, the fabric surface of the board 12 and the cream solder S
If the reflectance of
In order to ensure judgment accuracy, the reflectance may be made equal by a predetermined coloring operation, etc. Conversely, due to the difference in reflectance between the fabric surface of the board 12 and the cream solder S, a more detailed analysis of the content of printing misalignment may be performed. The determination may be made by performing the following.

In this way, if it is determined that the cream solder printing is defective in (S5), it is predicted that if the component is mounted on such a board, a defect will occur after the reflow process with a predetermined probability. The board discharging device 13 (FIG. 2) is activated, and the board determined to have a defective cream solder printing is stored in the defective board stocker 14 (SIO).

Further, when a defective board with cream solder printing occurs in this way, data representing a predetermined cream solder printing state is created based on the data and transmitted to the previous process using the interface cable 15 (FIG. 2). It is used to control position correction in the cream solder printing process, or is transmitted to a mounter in a subsequent process and used to control correction of the mounting position (Sll).

After this, the process moves to the next loading operation (S12).

Therefore, according to this embodiment, it is possible to reliably eliminate the cream solder printed defective board, which has a high probability of becoming defective after mounting the components, before mounting the components, and therefore it is possible to easily maintain a high manufacturing yield. can.

In addition, in this example, since it is implemented in combination with an electronic component mounting device, many functions such as image data capture using a TV camera etc. and data analysis processing necessary for determining a defective cream solder printed board can be performed. It becomes possible to share the functions originally possessed by this electronic component mounting device, and it is possible to achieve the effect that it can be implemented without any increase in cost.

〔Effect of the invention〕

According to the present invention, since the presence or absence of the possibility of causing subsequent defects is checked at the time of printing cream solder after component mounting, the occurrence of defects after component mounting is significantly suppressed. , the yield can be kept sufficiently high.

Further, according to the present invention, since the amount of solder can be controlled with high precision, high reliability can be obtained in soldering after components are mounted.
Higher quality substrates can be easily provided.

Furthermore, in the past, setting up a cream solder printing apparatus required a considerable number of trial printings, but according to the present invention, this process can be automated. In other words, as a result of the cream solder printing defect detection described above, data representing a predetermined cream solder printing state can be obtained based on the results, so that position correction in cream solder printing processing can be performed and automatic correction can be performed. It is.

By the way, if there is a misalignment in the cream solder printing,
After the component is placed on the board and before the flow process, or when the solder is in a molten state during the flow process,
There is a possibility that the parts may be misaligned. Therefore, according to the present invention, it is possible to reduce mounting misalignment of components due to such causes. In other words, according to the present invention, it is possible to avoid mounting components on a board where the cream solder print is misaligned, and even if the cream solder print is misaligned, it is not considered a defect. For boards that do not have the same position, data representing the positional deviation can be obtained, so this data is sent to the electronic component mounting device and used for component mounting position correction control. Anticipating the deviation
This is because it can be mounted at a corrected position. Therefore, according to the present invention, the best positional accuracy is always maintained and high reliability and work efficiency can be easily obtained.

Next, in such a ream solder printing device, if the printing mask used there becomes dirty, the ability to remove cream solder decreases and printing defects are more likely to occur.
Masks must be cleaned regularly, but according to the present invention, the timing at which masks should be cleaned can be meaningfully determined from the print judgment results. In comparison, rational cleaning becomes possible, and the addition of unnecessary man-hours can be avoided.

Furthermore, according to the present invention, it is possible to classify only the boards that require a cream solder print check using the board ejection device and the defective board stocker, thereby reducing the number of processes that require manual labor and increasing the automation rate. can.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the operation of an embodiment of the cream solder printing inspection device according to the present invention, FIG. 2 is a perspective view showing an example of an electronic component mounting device to which the embodiment of the present invention is applied, and FIG. 3 is an explanatory diagram of the imaging operation by the TV camera, and FIGS. 4, 5, 6, and 7 are explanatory diagrams of the cream solder printing defect determination operation, respectively. 1... Electronic component mounting device, 2... Orthogonal robot mechanism, 3... Board transfer section, 4...
...Parts supply department, 5.6...TV camera, 7.
...Image data analysis section, 8...Control section,
9...Mounter operation section, 10...Suction nozzle, 11...Head section, 12...
Substrate, 13...Substrate ejection device, 14...
- Defective board stocker, 15 interface cable. Figure 3 12: Rotating crystal 1 Lever 4 Correct 0 [pν1 Figure 5 E-rlJIsu) It AM to square -) y: & holder mark

Claims (6)

[Claims] 1. A cream solder printing apparatus that prints cream solder for mounting electronic components on a predetermined portion of a circuit pattern of a circuit board includes an imaging means that captures the predetermined portion of the circuit pattern as image data, and an image pickup means that analyzes the image data and prints the cream solder for mounting electronic components. and image data analysis means for detecting the printed state of the cream solder on a predetermined portion of the circuit pattern, and is configured to determine the quality of the cream solder printing based on the analysis result of the image data by the image data analysis means. A cream solder printing inspection device characterized by: 2. In the invention of claim 1, the quality determination of the cream solder printing is based on a level difference in the image data caused by a difference in light reflectance between the circuit pattern part of the circuit board and the cream solder application part. A cream solder printing inspection device characterized in that it is configured to perform inspection. 3. The cream solder according to claim 1, wherein the imaging means is attached to a movable member of a robot mechanism in an electronic component mounting device that automatically positions and mounts electronic components at predetermined positions on a circuit board. Print inspection equipment. 4. 2. The cream solder print inspection apparatus according to claim 1, wherein circuit boards determined to be defective are selected in accordance with the quality determination result of said cream solder print. 5. In the invention of claim 1, the amount of deviation of the cream solder printing is calculated based on the analysis result of the image data by the image data analysis means, and the cream solder printing position is corrected according to the calculation result. Features cream solder printing inspection equipment. 6. In the invention of claim 3, the amount of deviation of cream solder printing is calculated based on the analysis result of the image data by the image data analysis means, and the mounting position of the electronic component is corrected based on the calculation result. A cream solder printing inspection device characterized by: