JPH06232543A - Mounting method for component of printed board - Google Patents

Abstract

PURPOSE:To mount a component at a proper position on a pattern even if a printed board is thermally deformed in a thermal treatment carried out for soldering. CONSTITUTION:Components are mounted on the rear of a board through processes A-1 to A-7. At the start of an initial lot production, the positions of the surface patterns of a few sample boards are measured in a pattern measuring process A-8, and the positional deviation of the patterns is measured. After the patterns of the sample boards are measured, a pattern measuring process is skipped, and a board is transferred to an adhesive agent applying process. The positional deviation of a pattern is caused by the thermal deformation of a printed board in a flow soldering process A-7. An adhesive agent applying position and a component mounting position are corrected taking advantage of the measured positional deviation in an adhesive agent applying process B-1 and a component mounting process B-2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of mounting a component on a printed circuit board by mounting the component on the printed circuit board and then soldering the component. In particular, the present invention relates to a component mounting process. The present invention relates to a component mounting method in which a heat treatment process for soldering is performed in multiple stages to mount components.

[0002]

2. Description of the Related Art In recent years, in order to increase the mounting density of parts,
BACKGROUND ART Patterns are printed on both front and back surfaces of a printed circuit board, and a large number of electronic components are soldered to the front and back patterns, respectively. In this type of component mounting line, after applying adhesive to the component mounting position on the back surface of the printed circuit board,
A component is mounted by a component mounter, and then this substrate is dipped in a high temperature solder bath to solder the component to the back surface of the substrate.

Next, an adhesive is applied to the component mounting position on the surface of the printed circuit board, the component is mounted thereon by a component mounting machine, and the substrate is dipped in a high temperature solder bath to apply the component to the surface of the substrate. Solder.

[0004]

When mounting a component on the back surface of a printed circuit board, the printed circuit board is immersed in a solder bath,
The printed board is thermally deformed, and the pattern on the surface of the board is also deformed accordingly. As a result, when the adhesive is next applied to the front side of the substrate and the component is mounted by the component mounter, the position where the component is mounted with respect to the pattern on the substrate is displaced.

The present invention has been made in view of the above problems, and it is possible to mount a component at an appropriate position on a pattern even if the printed circuit board is deformed by a heat treatment process for soldering. An object of the present invention is to provide a component mounting method for a board.

[0006]

The present invention mounts a component on a printed circuit board by executing a step of assembling the component on the printed circuit board and a heat treatment step for soldering the incorporated component in a plurality of steps. The method is to measure the position of the pattern on the printed circuit board after the heating process and before the component assembling process, measure the amount of pattern displacement from the obtained value, and according to the amount of displacement. The position where the adhesive is applied and the position where the parts are incorporated are corrected.

[0007]

[Function] Even if the printed circuit board is thermally deformed by the heat treatment process in the previous step, the positional deviation amount of the pattern is measured before the next step of assembling the parts, and the adhesive application position is determined according to the measured value. Since the mounting position of the component is corrected, the component can be mounted at an appropriate position on the pattern.

[0008]

FIG. 1 shows a component mounting line to which the component mounting method of the present invention is applied. This component mounting line is for mounting a large number of electronic components on both front and back surfaces of a printed circuit board, and the components are mounted on the pattern on the back surface of the substrate through the steps A-1 to A-8 in the figure. Then, B-
Parts are mounted on the pattern on the surface of the substrate through the steps 1 to B-6.

A pattern including lands is formed on both surfaces of the printed circuit board by printing, and the printed circuit board is supplied to this component mounting line with its back surface facing upward.
First, in the A-1 adhesive application process, the adhesive is applied to the component mounting position on the back surface of the printed circuit board, and then in the A-2 component mounting process, each component is printed by a component mounter (not shown). It is installed at each mounting position on the board. CAD data obtained at the time of designing the board is previously taught to the component mounter, and the component mounter automatically incorporates each component at the component mounting position according to the teaching data. When all the components have been assembled, they are then sent to a mounting defect inspection process (A-3 process) for inspecting whether or not each component is mounted at an appropriate position.

This inspection is automatically carried out by the mounted component inspection apparatus. Each inspection region on the printed circuit board is sequentially imaged under predetermined illumination, and the mounting pattern of the component, that is, the component is missing, according to the imaged pattern. , Automatically judge the quality of parts position, parts orientation, etc.

If the mounting state is judged to be defective in the mounting defect inspection process of A-3, the printed circuit board is sent to the mounting defect correction process of A-4, and the defective components in the mounting condition are checked. Corrections are made. This correction is mainly performed manually, and the corrected substrate and the substrate determined to have a good mounting state are sent to the adhesive curing treatment step of A-5, and the adhesive is irradiated with ultraviolet rays to cure the adhesive. Curing treatment is performed.

In the next board reversing step A-6, the printed board is turned upside down so that the front surface faces upward, and in the next flow soldering step A-7, the back surface of the printed board is immersed in a solder bath. Parts are soldered. After the completion of soldering, the printed circuit board sends several sample boards to the A-8 pattern measurement process at the start of initial lot production of the target board. After the pattern measurement of the substrates of several samples is completed, the pattern measurement is not performed and B-1
Send to the adhesive application process.

After the position of the pattern on the surface of the printed board is measured by the pattern measuring device in the pattern measuring step A-8, the board is sent to the next adhesive applying step B-1. This pattern measuring step is performed in consideration of the thermal deformation of the printed circuit board that occurs in the flow soldering step A-7, and the amount of positional deviation from the pattern before thermal deformation is measured from the obtained value. , This value is transmitted to the adhesive applying step B-1 and the component mounting step B-2.

This pattern measuring step is also carried out by utilizing the image processing technique, and the principle of measuring the positional deviation amount is specifically shown in FIG. FIG. 2A shows the position of the land printed on the board. 10 is the position of the land before the deformation of the printed board due to heating, and 11 is the position of the land after the deformation of the printed board due to heating.

In the pattern measuring step, first, the inspection area 12 including the land 11 is imaged by the imaging device of the pattern measuring device, and then a histogram as shown in FIG. 2B is generated from this image. Reference numeral 15 is a histogram of the substrate before the positional displacement of the pattern occurs, and 16 is a histogram of the substrate after the positional displacement. The histogram may be generated from a grayscale image of the input image or a binary image of the input image. The image pickup device may be a color TV camera or a monochrome TV camera,
For a color image, a histogram is created by focusing on the land color, and for a monochrome image, a histogram is created by focusing on the land density.

In the histogram shown in FIG. 2B, the horizontal axis shows the X coordinate position and the vertical axis shows the frequency. The frequency is the sum of the densities of the land image constituent portion along the Y-axis direction for the grayscale image and the number of pixels of the land image constituent portion for the binary image. 13 and 14 are land ends, and the position where the frequency exceeds the threshold value or the position where the inclination of the histogram is the maximum is the land end.

A displacement amount d between the land end 13 before the printed circuit board is deformed by heating and the land end 14 after the deformation.
Is the amount of pattern displacement due to heat deformation. In addition,
To know the position of the land before heat deformation, CAD
Data may be used, or the land position where the land of the substrate before deformation is imaged by this pattern measuring device may be measured, or the numerical value measured by another method may be used.

In the B-1 adhesive application step, the adhesive is applied to the component mounting position of the printed circuit board, and the result is sent to the B-2 component mounting step. At this time, the position where the adhesive is applied is corrected based on the positional deviation amount of the pattern measured in the pattern measuring step A-8.

In the component mounting step B-2, the component is mounted on the printed circuit board by the component mounter and then sent to the adhesive curing process B-3. At this time, the component mounting position is corrected using the positional displacement amount of the pattern measured in the pattern measuring step of A-8.

In the adhesive curing process of B-3, the printed substrate is irradiated with ultraviolet rays to cure the adhesive. In the flow soldering process of B-4, the printed substrate is immersed in a solder bath. Solder the parts.

In the next soldering inspection step B-5, the soldering state of each soldering portion is inspected by an automatic soldering inspection apparatus. After the solder is corrected by the automatic solder corrector, the corrected substrate and the non-defective substrate are carried out from the component mounting line.

[0022]

As described above, according to the present invention, the position of the pattern on the printed circuit board is measured after the heating step and before the component assembling step, and the positional deviation amount of the pattern is measured from the obtained value. Since the position where the adhesive is applied and the position where the parts are installed are corrected according to the amount of positional deviation, even if the printed circuit board is deformed in the heat treatment process for soldering in the previous step, the parts are patterned. The remarkable effect of achieving the object of the invention is that it can be mounted at an appropriate position above.

[Brief description of drawings]

FIG. 1 is a process explanatory view showing a configuration of a component mounting line to which the present invention is applied.

FIG. 2 is an explanatory diagram showing a principle of measuring a positional deviation amount.

[Explanation of symbols]

 A-7 Flow soldering process A-8 Pattern measurement process B-1 Adhesive application process B-2 Component mounting process

Claims (1)

[Claims] 1. A method for mounting a component on a printed circuit board by performing a step of incorporating a component on a printed circuit board and a heat treatment step for soldering the incorporated component in a plurality of steps, the method comprising the steps of: That is, the position of the pattern on the printed circuit board is measured before the component assembly process, and the amount of pattern displacement is measured from the obtained values. A method for mounting a component on a printed circuit board, the method comprising: correcting a mounting position.