JPH11186711A - Apparatus and method for visual inspection of cream solder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and method for the visual inspection of cream solder printed on a board, which is capable of executing the appearance inspection in line with the present condition of a screen mask in accordance with well prepared programs. SOLUTION: The method comprises the steps of positioning a screen mask 4 on a guide rail 10, reading data such as position and size of pattern holes 6, using optical elements 13, removing the screen mask 4 from the guide rail 10, printing cream solder on a board 7, using this mask 4, positioning the board 7 on a conveyor 11, reading data such as the position and size of the cream solder, using optical elements, and comparing the read data of the pattern holes 6 with the solder data through a comparing means to determine the quality of the cream solder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cream solder appearance inspection apparatus and method for soldering electronic components.

[0002]

2. Description of the Related Art Cream solder for soldering electronic components to a substrate is printed on the substrate by a screen printing apparatus. The screen printing apparatus superimposes a screen mask on a substrate, and slides a squeegee on the screen mask to print cream solder on circuit pattern electrodes of the substrate through pattern holes formed in the screen mask. Things.

However, when cream solder is printed on a substrate by a screen printing apparatus, defects such as chipping, dripping, and small size of the cream solder are likely to occur. Then, the appearance inspection of the cream solder printed on the substrate is performed.

Conventionally, the appearance inspection of cream solder has been performed as follows. That is, after the cream solder is printed on the substrate using the screen mask, the substrate is taken out of the screen printing device and set in the visual inspection device.
Then, the position and size data of the cream solder are read by the optical element by the visual inspection device. In the memory provided in the visual inspection apparatus, a quality judgment reference value is registered in advance as reference data, and the quality of the cream solder appearance is judged by comparing the data with the reference data.

[0005]

However, in the above-mentioned conventional method, data registered in the memory in advance is used as absolute reference data, and the read data is compared with the reference data to determine the quality. If the reference data itself does not match the actual situation, there is a problem that a good product is easily erroneously determined as a defective product.

Accordingly, the present invention provides a cream solder appearance inspection apparatus and an appearance inspection method capable of setting up the appearance inspection of cream solder printed on a substrate in a well-designed manner and accurately performing in accordance with the current state of a screen mask. The purpose is to:

[0007]

According to the present invention, there is provided an apparatus for inspecting the appearance of cream solder, comprising: a positioning portion for a screen mask; a positioning portion for a substrate provided at the same plane as the positioning portion for the screen mask; An optical element for reading the data of the position and size of the pattern hole of the screen mask positioned on the screen mask and the position and size of the cream solder printed on the substrate with the screen mask, and moving means for moving the optical element in the horizontal direction, A memory for registering the data read by the optical element; and a judging means for judging the appearance of the cream solder by comparing the data of the screen mask with the data of the substrate.

[0008] The method for inspecting the appearance of cream solder according to the present invention comprises:
A step of reading the position and size data of the pattern holes of the screen mask positioned in the positioning portion by an optical element, and registering the read data in a memory; and a step of printing the cream solder printed substrate through the pattern holes of the screen mask. Positioning the positioning portion, the step of reading the position and size data of the cream solder by the optical element,
A step of comparing the data of the screen mask with the data of the substrate to determine whether the appearance of the cream solder is good or not by a determination unit.

According to the inventions having the above configurations, it is possible to accurately judge the appearance of the cream solder printed on the substrate, based on the current state of the pattern holes of the screen mask actually used.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a cream solder appearance inspection apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view showing the internal structure of the cream solder appearance inspection apparatus, and FIG. 3 is a cream solder appearance inspection apparatus. FIG. 4 is a block diagram of the cream solder appearance inspection apparatus, and FIG.
FIG. 5 is a plan view of a pattern hole of the screen mask, and FIG.
(B) is a plan view of the cream solder printed on the board, and FIG. 6 is a flowchart of the appearance inspection of the cream solder appearance inspection apparatus.

In FIG. 1, on the side of the main body case 1,
An opening 2 for taking in and out the screen mask and an opening 3 for taking in and out the substrate are provided.

In FIG. 2, a screen mask 4 is held by a mask holder 5, and a number of pattern holes 6 are opened. The substrate 7 has a circuit pattern electrode 8
Are formed, and cream solder is printed on these electrodes 8 through the pattern holes 6.

A pair of left and right guide rails 10 are provided inside the opening 2, and the screen mask 4 is positioned on the guide rails 10. That is, the guide rail 10 serves as a positioning portion of the screen mask 4. A pair of left and right conveyors 11 is provided below the guide rails 10, and the substrate 7 is positioned on the conveyor 11. This conveyor 11 serves as a positioning portion for the substrate 7. The screen mask 4 and the substrate 7 are positioned at the same plane position, so that the appearance can be recognized by a common optical element (described later).

2 and 3, reference numeral 13 denotes an optical element for reading an image, which comprises a line sensor, a CCD camera and the like. A nut 14 is connected to the optical element 13, and a horizontal feed screw 15 is screwed into the nut 14. The feed screw 15 is driven by a motor 16 to rotate. The feed screw 15 and the motor 16 are
Means of transportation. 17 is a guide rail of the optical element 13. The optical element 13 holds the feed screw 1 above the screen mask 4 positioned on the guide rail 10.
5 (see the arrow in FIG. 3), and the read image data is registered in the memory 21 (described later). The substrate 7 on which the cream solder is printed with the screen mask 4 is positioned on the conveyor 11, the optical element 13 is moved along the feed screw 15 above the substrate 7, and the read image data is registered in the memory.

In FIG. 4, a control unit (CPU) 20 is connected to an optical element 13, a motor 16, a memory 21, a comparing means 22, and the like.

This cream solder appearance inspection apparatus is configured as described above. Next, a cream solder appearance inspection method will be described with reference to the flowchart of FIG.
First, the screen mask 4 is positioned on the guide rail 10 (Step 1). Next, as shown in FIG. 3, the optical element 13 is moved above the screen mask 4, and an image on the screen mask 4 is read (step 2). The read image data is registered in the memory 21 and subjected to image processing by the control unit 20 (step 3).

FIG. 5A shows the contents of this image processing. In this image processing, the center of gravity G (x, y), length L and width W of the pattern hole 6 in the reference coordinate system (X, Y)
In addition, desirably, the control section 20 calculates the radius R1, R2, the opening area S, and the like. These data are stored in memory 2
1 is registered. More preferably, the screen mask 4
Auxiliary data such as the thickness of the object is also registered separately.

Next, the screen mask 4 is connected to the guide rail 1.
Then, cream solder is printed on the substrate 7 using a screen printing device (not shown) using the screen mask 4 (step 4). Next, the substrate 7 on which the cream solder is printed is carried into the conveyor 11 and positioned (step 5). Next, the image of the cream solder is read by the optical element 13 and the data is registered in the memory 21 (step 6). Next, as in the case of step 3, in addition to the center of gravity G '(x', y '), length L', and width W 'of the cream solder shown in FIG. 5B, the radius shapes R1' and R2 ' And the printing area S 'are calculated by the control unit 20 (step 7). Preferably, a laser displacement meter may be provided above the substrate 7, and the height of the cream solder may be measured together with a laser beam.

Next, the data of the pattern hole 6 and the data of the cream solder are compared by the comparing means 22 to determine whether or not the difference between them is within an allowable range (step 8). And Ye
If s, screen printing is continued (step 9),
If so, the operator is notified of the fact and the screen printing is stopped (step 10).

In the above embodiment, the inspection of the screen mask and the inspection of the cream solder are performed by the same apparatus. However, each inspection may be performed by a separate apparatus.

[0021]

According to the present invention, data of pattern holes of a screen mask actually used is read by an optical element, and data of cream solder printed on a substrate using the screen mask is read by an optical element. Since the quality of the cream solder printing is determined by comparing the data obtained in this way, the quality determination can be accurately performed in accordance with the current situation.

[Brief description of the drawings]

FIG. 1 is a perspective view of a cream solder appearance inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing the internal structure of the cream solder appearance inspection apparatus according to the embodiment of the present invention;

FIG. 3 is a partial side view of the cream solder appearance inspection apparatus according to the embodiment of the present invention;

FIG. 4 is a block diagram of a cream solder appearance inspection apparatus according to an embodiment of the present invention.

5A is a plan view of a pattern hole of a screen mask according to one embodiment of the present invention. FIG. 5B is a plan view of cream solder printed on a substrate according to one embodiment of the present invention.

FIG. 6 is a flowchart of an appearance inspection of a cream solder appearance inspection apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 4 screen mask 6 pattern hole 7 substrate 8 electrode 9 cream solder 10 guide rail 11 conveyor 13 optical element 14 nut 15 feed screw 16 motor 20 control unit 21 memory 22 comparison means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B41M 1/12 B41M 1/12 G01N 21/88 G01N 21/88 F

Claims (2)

[Claims] 1. A positioning portion of a screen mask, a positioning portion of a substrate provided at the same plane as the positioning portion of the screen mask, positions and dimensions of pattern holes of the screen mask positioned at each of the positioning portions, and An optical element for reading the position and size data of the cream solder printed on the substrate with a screen mask, moving means for moving the optical element in a horizontal direction, a memory for registering the data read by the optical element, and the screen A cream solder appearance inspection apparatus, comprising: a determination unit that determines whether the appearance of the cream solder is good or not by comparing the data of the mask with the data of the substrate. 2. A step of reading, by an optical element, data on the position and size of a pattern hole of a screen mask positioned at a positioning portion, and registering the read data in a memory. The cream solder passes through the pattern hole of the screen mask. Positioning the printed board on the positioning section, reading the position and size data of the cream solder by the optical element, and comparing the data of the screen mask with the data of the board to determine the quality of the appearance of the cream solder A method for inspecting the appearance of cream solder.