JP3041107B2 - Cream solder printing inspection method and cream solder printing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cream solder printing on a printed circuit board used in electronic equipment, and more particularly to a cream solder printing inspection method for inspecting the printed state of cream solder and a cream solder printing method using this method. It is about.

[0002]

2. Description of the Related Art A conventional example of a cream solder printing inspection method for inspecting the printing state of cream solder printing applied to a printed circuit board will be described with reference to FIGS.

As shown in FIG. 7, in a conventional example, a printed board 31 on which cream solder printing is performed is disposed below a laser height measuring instrument 30, and this printed board 31
The horizontal relative position with respect to the laser altimeter 30 is moved in the XY direction by a Y table (not shown). Then, with respect to the cream solder printed on each land, the height of the cream solder printed on the land is measured by the laser height measuring device 30 by the triangulation method, and the measurement result enlarged view for each land shown in FIG. The distribution data in the XY directions of the cream solder height H as shown in FIG. From the distribution data, the volume of the solder printed on each land and the area of the portion where the solder is printed when viewed from above are calculated, and the quality of the printed state is determined from the calculation result.

[0004]

However, according to the conventional cream solder printing inspection method, it is possible to inspect the printing state of the screen printed cream solder for each land. The screen is checked for inclination. If the screen is inclined, it is necessary to correct the inclination so that better screen printing can be obtained. Of the maximum point of the cream solder height H of each land is calculated as X−
It is necessary to obtain a plane for approximating the series in the Y-plane direction by a plane approximation calculation as an indication of the screen surface, which has a problem that it takes an enormous amount of time for measurement and calculation.

In the conventional cream solder printing method, there is no method for easily measuring the inclination of the screen and feeding back the inclination data to correct or remove the inclination of the screen during printing.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cream solder printing inspection method capable of detecting the screen inclination in a short time and a cream solder printing method using this method, which solves the above problems.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a cream solder printing inspection method, comprising: a surface on at least two measurement straight lines which traverses a printed circuit board on which cream solder is printed; The height is continuously measured, and the height measurement and storage step of storing the height data, and the height data for each of the measurement straight lines stored in the height measurement and storage step, For each measurement straight line, the maximum point straight line approximation line that connects the series of the maximum points of the height of the cream solder printed on the lands on the measurement straight line by linear approximation and the cream solder printing on the measurement straight line A maximum point / minimum point straight line approximation step for calculating a minimum point straight line approximation line connecting and connecting a series of minimum points of the height of the absent portion with a straight line, and at least two measurement straight line lines DOO in the slope between the maximum point linear approximation line and the minimum point linear approximation line on the measurement straight line,
A tilt detecting step of calculating and calculating the tilt of the screen for screen printing with respect to the printed circuit board from the tilts.

In order to solve the above-mentioned problems, the cream solder printing method according to the present invention is directed to a cream solder printing method using a screen. A height measurement and storage step of continuously measuring the upper surface height and storing the height data;
From the height data for each of the measurement straight lines stored in the storage step, for each of the measurement straight lines, a series of the maximum points of the height of the cream solder printed on the lands on the measurement straight line is linearly approximated. The maximum point obtained by calculating the maximum point linear approximation line that is obtained by calculating the maximum point linear approximation line that is connected by linear approximation of the series of the maximum point linear approximation line A minimum point straight line approximation step, and for each of at least two measurement straight line lines, a slope between the maximum point straight line approximation line and the minimum point straight line approximation line on the measurement straight line is calculated and obtained, and from these slopes A tilt detecting step of detecting a tilt of the screen for the screen printing with respect to the printed circuit board, and correcting and removing the tilt of the screen based on the detected tilt of the screen. Characterized by comprising the control step of.

[0009]

According to the cream solder printing inspection method of the present invention, the measuring time can be continuously measured in parallel with the surface heights on at least two measurement straight lines traversing the screen printed printed circuit board. , And the data is merely stored, so that the process can be completed in a very short time as compared with the conventional example in which the distribution of the maximum point of the height H of the cream solder on the land over the entire printed circuit board is obtained. .

The calculation time is determined by the least squares method or the like for each measured straight line. The maximum point linear approximation line is obtained by linearly approximating the change of the maximum point, and the minimum value is obtained by linearly approximating the change of the minimum point. Since the point straight line approximation line is obtained and only the slope between the maximum point straight line approximation line and the minimum point straight line approximation line is obtained, the conventional example is the X of the maximum point of the height H of the cream solder of each land on the entire printed circuit board. -Comparing to calculate a plane that approximates a series in the Y-plane direction,
It can be completed in a very short time.

Here, the maximum point straight line approximation line indicates the height of the solder on the measurement straight line and the height of the screen, and the minimum point straight line approximation line indicates the height of the substrate on the measurement straight line. Is represented. Since the inclination of the screen with respect to the substrate is the inclination between the height of the screen and the height of the substrate, the inclination between the two straight line approximation lines is equal to the inclination of the screen with respect to the printed circuit board on the measurement straight line. Become. Since the inclination of the screen with respect to the printed circuit board on the measurement straight line is obtained on at least two measurement straight lines,
The inclination of the screen with respect to the substrate can be detected based on the principle of limiting the plane with two straight lines, and the detection of the inclination can be completed in a very short time as compared with the conventional example.

According to the cream solder printing method of the present invention, with the above configuration, the inclination of the screen with respect to the substrate is detected in a very short time, the detection result is fed back, and the inclination of the screen with respect to the substrate is determined during the printing operation. Can be modified and removed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the cream solder printing inspection method of the present invention will be described with reference to FIGS.

FIG. 1 is a flowchart of this embodiment.

In the height measuring / storing step of step # 1, the surface heights on at least two measurement straight lines crossing the printed circuit board on which the cream solder is printed are measured in parallel and continuously. , And stores the height data, and proceeds to step # 2.

In the maximum point / minimum point straight line approximation step of step # 2, the height data of each measurement straight line stored in the height measurement / storage step of step # 1 is used for each of the measurement straight line. Calculating a maximum point straight line approximation line connecting the series of the maximum points of the height by linear approximation and connecting a series of the minimum points of the height by linear approximation to obtain a step # Proceed to 3.

In the inclination detecting step of step # 3, the data of the maximum point straight line approximation line and the minimum point straight line approximation line obtained in the maximum point / minimum point straight line approximation step of step # 2 are
The slope between the maximum point straight line approximation line and the minimum point straight line approximation line is calculated and calculated for each of at least two measurement straight line lines, and the inclination of the screen for screen printing with respect to the printed circuit board is detected from these inclinations. .

FIG. 2 shows a cream solder printing inspection apparatus using one embodiment of the cream solder printing inspection method of the present invention. In this method, a printed circuit board 4 on which cream solder is screen-printed is placed below laser altimeters 1 and 2 for measuring height by triangulation, and the printed circuit board 4 is placed on a table as shown in FIG. The driving means 5 moves the laser height measuring devices 1 and 2 in the horizontal direction. At this time, the laser height measuring device 1 continuously measures the surface height on the measurement straight line A, and the laser height measuring device 2 continuously measures the surface height on the measurement straight line B, and these heights are measured. The height data is transmitted to the height data storage means 6, and the height data storage means 6 stores the height data. The height data stored in the height data storage means 6 is stored in a maximum point detection means 7 and a minimum point detection means 8.
Are sequentially read to detect the maximum point and the minimum point of the height, respectively, and transmit the data of the maximum point and the minimum point to the linear approximation means 9. The point data is received, and the maximum of the height of each of the two measurement straight lines A and B is obtained from the data of the maximum and minimum points of the heights of the two measurement straight lines A and B by the least square method or the like. A maximum point straight line approximation line connected by linear approximation of a series of points and a minimum point straight line approximation line connected by linear approximation of a minimum point of the height are calculated and obtained. send.

As shown in FIG. 5, the inclination detecting means 10
The slope between the maximum point straight line approximation line and the minimum point straight line approximation line is determined for each of the two measurement straight lines A and B.
The slope between the straight line connecting the end points of the two maximum point straight line approximation lines and the straight line connecting the end points of the two minimum point straight line approximation lines is obtained,
From these inclinations, the inclination of the screen with respect to the substrate can be detected. If the orientation of the screen is corrected and controlled so that these inclinations become zero, the screen becomes parallel to the printed circuit board, and the quality of screen printing of cream solder is improved. The control unit 11 controls the entire cream solder print inspection device.

An embodiment of the cream solder printing method of the present invention will be described with reference to FIG.

FIG. 6 is a flowchart of this embodiment.

In the screen printing process of step # 1, cream solder is screen-printed on a printed circuit board, and the process proceeds to step # 2.

In the height measuring and storing step of step # 2, the surface heights of at least two measurement straight lines crossing the printed circuit board on which the cream solder is printed are measured in parallel and continuously. , And stores the height data, and proceeds to step # 3.

In the maximum point / minimum point straight line approximation step of step # 3, the height data of each measurement straight line stored in the height measurement / storage step of step # 2 is used for each measurement straight line. Calculating a maximum point straight line approximation line connecting the series of the maximum points of the height by linear approximation and connecting a series of the minimum points of the height by linear approximation to obtain a step # Proceed to 4.

In the inclination detection step of step # 4, the data of the maximum point straight line approximation line and the minimum point straight line approximation line obtained in the maximum point / minimum point straight line approximation step of step # 3 are
The slope between the maximum point straight line approximation line and the minimum point straight line approximation line is calculated and calculated for each of at least two measurement straight line lines, and the inclination of the screen for screen printing with respect to the printed circuit board is detected from these inclinations. Then, proceed to step # 5.

In the control process of step # 5, step # 4
The inclination of the screen for screen printing with respect to the printed circuit board is corrected and removed based on the inclination of the screen detected in the inclination detecting step.

The cream solder printing inspection method and the cream solder printing method of the present invention are not limited to the above-described embodiment, and various embodiments are possible. For example, a height measuring instrument is not limited to a laser height measuring instrument as long as it performs the same function. If the number of measurement lines is three or more, warpage of the screen and the like can be detected.

[0028]

According to the cream solder printing inspection method of the present invention,
The inclination of the screen with respect to the printed circuit board is detected by the slope between the maximum point straight line approximation line and the minimum point straight line approximation line on the measurement straight line. Compared with the conventional technology, in which the calculation of the plane approximation is troublesome, the screen printing of the cream solder applied to the printed circuit board can be inspected in a very short time, and the inclination between the screen and the printed board can be detected. .

According to the cream solder printing method of the present invention, the screen printing of cream solder applied to a printed circuit board is inspected in a very short time as compared with the prior art, and the inclination between the screen and the printed circuit board is detected. This detection result is fed back, and the position of the screen is corrected so that the inclination between the screen and the printed circuit board is set to 0, so that the quality of screen printing can be improved.

[Brief description of the drawings]

FIG. 1 is a flowchart of one embodiment of a cream solder printing inspection method according to the present invention.

FIG. 2 is a configuration diagram of a cream solder print inspection apparatus using the embodiment method of FIG. 1;

FIG. 3 is an operation diagram of the embodiment of FIG. 1;

FIG. 4 is an inspection principle diagram based on the operation of FIG. 3;

FIG. 5 is an inspection principle diagram of FIG. 1;

FIG. 6 is a flowchart of an embodiment of a cream solder printing method according to the present invention.

FIG. 7 is an operation diagram of a conventional example.

8 is a principle diagram of the inspection by the operation of FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 2 Laser height measuring device 3 Cream solder 4 Printed circuit board 5 Table drive means 6 Height data storage means 7 Maximum point detection means 8 Minimum point detection means 9 Linear approximation means 10 Inclination detection means 11 Control part

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuhisa Sano 1006 Kazuma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (56) References JP-A-3-193449 (JP, A) JP-A-4-8578 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41F 15/08 B41F 15 / 26 B41F 33/14 H05K 3/12

Claims (2)

(57) [Claims] 1. A height measuring and storing step of continuously measuring surface heights on at least two measurement straight lines across a printed circuit board on which a cream solder is screen-printed and storing the height data. And, from the height data for each of the measurement straight lines stored in the height measurement and storage step, for each of the measurement straight lines, the height of the cream solder printed on the land on the measurement straight line A linear approximation line that connects the maximum point straight line approximation and connects the maximum point linear approximation line that connects the maximum point straight line approximation, and a minimum point linear approximation line that connects the series of minimum points at the height of the part where there is no cream solder printing on the measurement straight line A maximum point / minimum point straight line approximation step obtained by calculation, and a slope between the maximum point straight line approximation line and the minimum point straight line approximation line on each of the at least two measurement straight line lines And an inclination detecting step of detecting the inclination of the screen for screen printing with respect to the printed circuit board from these inclinations. 2. A cream solder printing method using a screen, wherein the surface height of at least two measurement straight lines traversing the screen board on which the cream solder is printed is continuously measured, and the height is measured. A height measuring and storing step of storing data, and a height on each of the measuring straight lines based on the height data of each of the measuring straight lines stored in the height measuring and storing step. A straight line approximation of the maximum point straight line approximation line that connects the series of the maximum points of the cream solder height printed on the line by linear approximation, and the minimum point of the height of the part without the cream solder printing on the measurement straight line A maximum point / minimum point straight line approximation step of calculating and calculating a minimum point straight line approximation line to be connected, and for each of the at least two measurement straight line lines, A slope between the maximum point straight line approximation line and the minimum point straight line approximation line, and a slope detection step of detecting a screen inclination of the screen printing with respect to the printed circuit board from the inclinations, and the detected screen And a control step of correcting and removing the inclination of the screen based on the inclination of the screen.