JPH06328661A - Screen printer of solder for printed circuit board - Google Patents

Abstract

PURPOSE:To make it possible to always check the quantity of cream solder remaining on the upper surface of a printing screen. CONSTITUTION:An automatic squeegee 2 is provided with a noncontact type distance sensor 1 which measures by an ultrasonic wave a distance (y) to a collected body 11a of cream solder 11 collected in the vicinity of a contact part 7 of a squeegee plate part 2a of the automatic squeegee 2 with a printing screen 4. The noncontact type distance sensor 1 transmits the ultrasonic wave to the collected body 11a of the cream solder collected at the contact part 7 of the squeegee plate part 2a of the automatic squeegee 2 with the printing screen 4, receives a reflected wave of the ultrasonic wave from the collected body 11a of the cream solder 11 and calculates the distance (y) on the basis of the time required from the start of transmission of the ultrasonic wave to the start of reception of the reflected wave.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder screen printing apparatus for printed boards.

[0002]

2. Description of the Related Art FIG. 2 is a diagram showing a conventional example of a solder screen printing apparatus for a printed circuit board. In FIG. 2, reference numeral 4 is a printing screen, which has a lower surface 4c on which the printed board 10 abuts, and pattern holes 4a, 4a, ... Formed corresponding to solder lands on the printed board 10.
Reference numeral 6 denotes an automatic squeegee, which has a squeegee plate portion 2a and an upper end of the squeegee plate portion 2a fixed to the squeegee plate portion 2a.
And a drive unit 2b for moving the. The automatic squeegee 2 has the tip edge of the squeegee plate portion 2a in contact with the upper surface 4b of the printing screen 4 without any gap, and while scraping the cream solder 11 existing on the upper surface 4b of the printing screen 4. Upper surface 4b of the printing screen 4
Is designed to slide. As the sliding movement of the automatic squeegee 2 progresses, the scraped cream solder 11 accumulates in the vicinity of the contact portion 7 between the automatic squeegee 2 and the printing screen 4 to form an aggregate 11a. While 2 slides, a small amount of the cream solder 11 among the cream solder 11 accumulated in the connection portion 7 enters the pattern holes 4a, 4a, ... And screen-prints on the solder land of the printed board 10. It is supposed to be done.

Reference numeral 5 is a support for supporting the printed circuit board 10 in a fixed position. The printed circuit board solder screen printing apparatus comprises the printing screen 4, the automatic squeegee 2 and the support 5 in FIG.

In the above-described solder screen printing apparatus for a printed board, the amount of solder cream remaining on the upper surface 4b of the printing screen 4 decreases as the screen printing of the cream solder 11 on the printed board 10 is repeated. Therefore, it is necessary to supply new cream solder 11 to the upper surface 4b of the printing screen 4.

[0005]

In the conventional solder screen printing apparatus for a printed circuit board, the number of repetitions of screen printing on the printed circuit board 10 is counted, and when the number of repetitions exceeds a certain number, the cream is applied. Although the solder 11 is supplied, according to this method, the cream solder 11 runs short before the number of times the screen printing is repeated reaches a certain number depending on the amount of the cream solder 11 supplied last time. However, in the worst case, there is a problem that the printing of the cream solder 11 on the printed circuit board 10 is faint.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a solder screen printing apparatus for a printed board capable of always checking the amount of cream solder remaining on the upper surface of the printing screen. To provide.

[0007]

SUMMARY OF THE INVENTION The present invention, which was conceived to solve the above-mentioned problems, provides a printing screen comprising a printed board which is in contact with a lower surface thereof and which is provided with a pattern hole corresponding to a solder land on the printed board. A solder screen printing apparatus for a printed circuit board, comprising: an automatic squeegee that slides on the upper surface of the printing screen while scraping cream solder existing on the upper surface of the printing screen; The automatic squeegee is characterized in that a non-contact type distance sensor for measuring the distance to the aggregate of cream solder accumulated in the vicinity of the contact portion is arranged on the automatic squeegee.

[0008]

According to the present invention, the amount of cream solder remaining on the upper surface of the printing screen can be checked.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing its embodiments. The corresponding parts in the conventional example are designated by the same reference numerals, and the description thereof will be omitted here.

FIG. 1 is a side sectional view of an essential part showing an embodiment of a solder screen printing apparatus for a printed board according to the present invention.
In the solder screen printing apparatus for a printed circuit board of the present embodiment, in the solder screen printing apparatus for a printed circuit board shown in the conventional example, the non-contact type distance sensor 1 is fixedly arranged on the drive unit 2b of the automatic squeegee 2. It is characterized by having done.

The distance sensor 1 is a non-detecting body (here, an assembly 11a of cream solder 11 accumulated near a contact portion 7 between the automatic squeegee 2 and the printing screen 4).
And a wave receiver for receiving the reflected wave of the ultrasonic wave in the non-detection body, and a wave transmitter for transmitting the ultrasonic wave from the wave transmitter. The time from the start to the start of reception of the reflected wave in the wave receiver, that is, the position where the distance sensor 1 is arranged and the cream solder 11 accumulated near the contact portion 7 between the automatic squeegee 2 and the printing screen 4. The round-trip time of ultrasonic waves with the aggregate 11a is measured immediately before the start of movement of the automatic squeegee 2, at the time of movement, and at the end of movement, and based on the round-trip time, the distance sensor 1 to the cream solder 11 moves. The distance y to the aggregate 11a is calculated. Further, a threshold value y1 is set for the distance y, and when the distance y exceeds the threshold value y1, a notification sound is emitted from a notification speaker or the like.

That is, in the solder screen printing apparatus for a printed circuit board of the present embodiment, the cream accumulated in the vicinity of the contact portion 7 between the squeegee plate portion 2a of the automatic squeegee 2 and the printing screen 4 by the distance sensor 1 is used. Solder 1
It is possible to know the height of the aggregate 11a of the cream solder 1 and the cream solder 1 that remains on the upper surface of the printing screen 4.
The remaining amount of 1 can be measured. When the remaining amount of the cream solder 11 remaining on the upper surface of the printing screen 4 is reduced to a certain level or less, the notification sound is made to sound. Therefore, when the notification sound is made, the printing is performed. New cream solder 11 on the upper surface 4b of the screen 4
To supply.

According to the present invention configured as described above, the remaining amount of the cream solder 11 remaining on the upper surface 4b of the printing screen 4 can be checked, and the printing screen 4 can be checked.
It is possible to accurately know the time when the cream solder 11 is supplied to the printed circuit board 1 and the printed circuit board 1 due to the shortage of the cream solder 11.
It is possible to prevent the print solder paste 11 from being printed on the surface of the printed circuit board 0, and to always ensure stable print quality.

[0014]

According to the present invention configured as described above, it is possible to check the remaining amount of the cream solder remaining on the upper surface of the printing screen, and to accurately know the supply time of the cream solder to the printing screen. Can be done.

[Brief description of drawings]

FIG. 1 is a side sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a side sectional view of a main part showing a conventional example.

[Explanation of symbols]

 1 distance sensor 2 automatic squeegee 2a squeegee plate part 2b drive device part 4 printing screen 7 contact part between the automatic squeegee 2 and the printing screen 4a upper surface of the printing screen 4b lower surface of the printing screen 10 printed board 11 cream solder 11a cream solder 11 Aggregation

Claims (1)

[Claims] 1. A printing screen in which a printed board is in contact with a lower surface and pattern holes corresponding to solder lands on the printed board are formed, and the cream solder existing on the upper surface of the printing screen is scratched to scratch the printed screen. A solder screen printing device for a printed circuit board, comprising an automatic squeegee that slides on an upper surface, and measures a distance to an aggregate of cream solder accumulated near a contact portion between the automatic squeegee and the printing screen. A solder screen printing device for a printed circuit board, wherein a contact type distance sensor is arranged on the automatic squeegee.