JPH0957937A - Manufacture of metal mask for screen printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize high print quality and print precision by forming a pore having a wall face of low roughness without attachment of fine melting matter. SOLUTION: After a metal plate 1 is irradiated with laser beam so as to form a pattern consisting of a fine pore 3 on the metal plate 1, a grainy abrasive is sprayed on the plate face of the metal plate 1 from an oblique direction so as to polish by sand blast. Concretely, in a state that the metal plate 1 is being inclined, the grainy abrasive is sprayed from the surface of the metal plate 1, that is, from the side to which a printing paste is to be added of the metal plate 1. For the grainy abrasive, alumina or carbon abrasive of #100-1500 are generally used. The spraying speed is generally set to 400-1000m/sec.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screen-printing metal used for screen-printing a printing paste such as cream solder on a circuit board when mounting a circuit component on an electronic device and soldering it. The present invention relates to a mask manufacturing method.

[0002]

2. Description of the Related Art A metal mask for screen printing has a pattern of pores for printing a cream solder paste, a conductive ink or the like. The conventional most common method for producing such a metal mask for screen printing. Is an etching method. In this etching method, an image is formed by an etching photoresist on a metal plate such as stainless steel, and then double-sided etching is performed with an etching solution to form a pattern of pores.

In addition, with the recent spread of CAD / CAM technology and the spread of laser processing machines, the fine processing technology of metal utilizing these characteristics has been improved, and the examination of the production of a metal mask for screen printing by the laser processing method has been improved. And, it is being introduced. In the production of screen printing metal masks by this laser processing method, laser equipment and automatic XY
This is a method in which the pores are directly processed and formed from CAD data by performing NC control on the table. This is because by directly laser processing from the data obtained by CAD, the processing accuracy can be improved and the construction period can be shortened.
It is expected as an effective manufacturing method.

FIG. 5 (a) shows an example of the cross-sectional shape of the pores 3 perforated in the metal plate 1 in the screen printing metal mask manufactured by the laser processing method. Here, a protrusion is formed on the side opposite to the laser beam incident surface side 1a of the metal plate 1, that is, around the opening of the pore 3 on the laser beam emitting side 1b. This is a molten deposit called dross formed by welding metal scraps generated by laser processing around the openings of the pores 3. Since the dross 2 impairs printability during printing, the surface 1b of the metal plate 1 is polished,
As shown in (b), the dross 2 is removed. The screen-printing metal mask thus obtained is generally provided on the laser beam incident side 1a of the metal plate 1.
Is used to contact the printing surface of the printed circuit board during printing and the other surface to contact the squeegee.

[0005]

However, in the conventional metal mask for screen printing by the laser processing method, the surface roughness (average roughness) of the wall surface of the pores 3 of the metal plate 1 formed by the irradiation of the laser beam is averaged. S: Height) is large. In addition, a fine melt generated during laser processing adheres to the wall surface of the pores 3 formed by the irradiation of laser light. As a result, the passability of the printing paste such as cream solder in the pores 3 during printing is poor, which has been a cause of lowering printing quality and printing accuracy. The present invention, in view of the problems of the method for producing a metal mask for screen printing by such a conventional laser processing method, the surface roughness is small, it is possible to form pores having a wall surface without adhesion of fine melt, This provides a printing method capable of manufacturing a metal mask for screen printing capable of realizing high printing quality and printing accuracy.

[0006]

According to the present invention, in order to achieve such an object, a fine abrasive grain 3 formed by irradiating a metal plate 1 with a laser beam 7 is sprayed with a granular abrasive to polish it. At that time, the spraying direction of the granular abrasives on the plate surface of the metal plate 1 was made oblique with respect to the plate surface of the metal plate 1. As a result, not only the dross is removed but also the pores 3
The surface roughness of the wall surface of No. 3 was reduced, and the fine melt adhered to the wall surface of the pores 3 was removed.

That is, in the method for manufacturing a metal mask for screen printing according to the present invention, the laser light 7 is applied to the metal plate 1.
After forming a pattern by irradiating the metal plate 1 with fine pores 3, the metal plate 1 is sandblasted by obliquely spraying a granular abrasive onto the plate surface of the metal plate 1. Here, the granular abrasive is preferably sprayed from the surface side of the metal plate 1, that is, the side of the metal plate 1 to which the printing paste is applied. Further, when the granular abrasive is sprayed on the metal plate 1, it is preferable to perform it while the metal plate 1 is inclined and held. The granular abrasives used in this case are # 100- #
An alumina-based or carbon-based abrasive of 1500 is common.

In such a method for producing a metal mask for screen printing according to the present invention, since the granular abrasive is sprayed obliquely to the plate surface of the metal plate 1, the metal plate 1 is irradiated with the laser beam 7. The granular abrasive material directly collides with the peripheral wall of the fine pores 3 thus formed, and the wall surface of the pores 3 is polished. Therefore, not only the dross attached to the periphery of the opening of the pore 3 is removed, but also the wall surface of the pore 3 is polished,
As the surface roughness decreases, the fine melt adhered to the walls of the pores 3 is also removed at the same time. Therefore, the pores 3
The wall surface of the
Print quality and print accuracy can be improved.

In this method for producing a metal mask for screen printing, the spray rate of the granular abrasive is 400-100.
It is preferably 0 m / sec. This is because if the spray rate of the granular abrasive is lower than 400, a sufficient polishing effect cannot be obtained, and the spray rate of the granular abrasive is 10 or less.
If it is higher than 00 m / sec, the metal mask may be deformed or the edge of the opening may be missing, making it difficult to print a desired pattern.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described specifically and in detail with reference to the drawings. FIG. 4 shows the appearance of the metal mask for screen printing. This metal mask stretches the mesh-shaped screen gauze 5 on the screen frame 4 having a square frame shape while applying tension to the screen gauze 5, and further has a thin square stainless plate coated with an epoxy resin adhesive at the peripheral edge ( A metal plate 1 such as a SUS304 plate) is overlapped and adhered to the central portion of the screen plate 4 and the adhesive is cured, and then the screen plate 5 overlapping with the peripheral portion of the metal plate 1 is cut off. It is a thing.

This metal mask for screen printing is shown in FIG.
As shown in (a), it is held by a holding jig 8 and set in a laser processing machine. That is, the screen frame 4 is sandwiched by holding jigs 8 from both sides, the holding jigs 8 are placed on an automatic XY table (not shown), and the metal plate 1 attached to the screen 5 is held horizontally. A laser head 6 using a YAG laser or the like is arranged on the automatic XY table. The laser head 6 moves a laser beam while moving the metal plate 1 on the automatic XY table in the X and Y directions by NC control. The metal plate 1 is irradiated with light 7 to form a large number of pores 3 at predetermined positions on the metal plate 1 to form a required pattern. As the laser oscillator of this laser processing machine, for example, a pulse oscillation type or the like is used.

Next, the surface of the metal plate 1 on which the pattern of the pores 3 is formed on the laser beam emitting side 1b is surface-polished with an abrasive material of about # 1500 to open the openings of the pores 3. Remove the surrounding dross 2. Next, the metal mask for screen printing polished in this manner was used as shown in FIG.
As shown in (b), it is held by a holding jig 11 and set in a sandblast polishing machine. That is, the screen frame 4 is sandwiched by the holding jigs 11 from both sides, and the holding jigs 1
1 is placed on a table of a sandblasting machine (not shown), and the upper and lower surfaces thereof are opposite to those at the time of laser processing, that is, the laser beam emitting side 1b is facing up.
The metal plate 1 attached to is tilted and held. At this time, the inclination angle θ ₁ of the metal plate 1 is 10 ° or more, preferably 30 °
Above. For example, in the example of FIG. 1B, it is held at an inclination angle of 45 °.

A blast nozzle 9 is arranged on the metal plate 1 held in this manner, and from there, a granular abrasive 10 is added in a range of 400 m / sec to 10 along with a medium such as water.
00 m / sec, more preferably 600 m / sec-
The metal plate 1 is sprayed at a speed of 900 m / sec.
The blast nozzle 9 is preferably installed so that the angle θ ₂ with respect to the plate surface of the metal plate 1 is 30 ° or more, preferably 45 ° or more. For example, in the example of FIG. 1 (b), it is installed at an angle of θ ₂ = 60 °.

As the granular abrasive, # 100 to # 150
0, more preferably # 400 to # 800 alumina-based or carbon-based abrasives are used. For example, when the metal plate 1 is made of stainless steel, the abrasive force of # 100 or less is too strong to easily change the shape of the pores 3, and the granular abrasive of # 1500 or more,
Since the polishing power is too weak, the surface roughness of the wall surface of the pores 3 is reduced,
It is difficult to remove fine melts.

In this way, a schematic view of the portion of the pores 3 when the granular abrasive is sprayed on the surface of the metal plate 1 at an angle inclined with respect to the plate surface of the metal plate 1 and sandblasted is shown in FIG. Show. θ ₁ is the inclination angle of the metal plate 1, and θ ₂
Is an inclination angle of the blast nozzle 9 with respect to the metal plate 1.
By sandblasting the metal plate 1 having the pores 3 in this manner, the granular abrasive 10 directly collides with the wall surface of the pores 3 of the metal plate 1. As a result, as shown in FIG. 3, the wall surfaces of the pores 3 forming the pattern of the metal plate 1 are smoothed, and the surface roughness is reduced. Further, the melt adhered to the wall surface of the pore 3 is also removed.

[0016]

EXAMPLES Next, specific examples of the present invention will be described by giving specific numerical values. (Embodiment 1) As shown in FIG. 4, while applying a constant tension to a mesh-shaped screen cloth 5, the mesh screen cloth 5 is set to 320 in length and width.
It was stretched on the screen frame 4 in the form of a square frame of mm.
Furthermore, as a metal plate, each length and width is 240 mm, thickness 150 μm
Using a square stainless steel plate (SUS304 plate), an epoxy resin adhesive is applied to the peripheral edge of the metal plate 1, and then the metal plate 1 is overlaid on the center of the screen 4, and in this state about 6 The adhesive was left to stand for about an hour to dry, cure, and bond. Then, from the outer shape of the metal plate 1, 10
A part of the screen 5 overlapping the inner part of mm was cut off.

Next, the screen printing metal mask was held by a holding jig 8 as shown in FIG. 1A, and this was set in a laser beam machine. Then, while moving the metal plate 1 on the automatic XY table by NC control, the laser head 6 outputs 10 W, the spot diameter of the laser light 7 is 40 μm, and the focal length is 30 mm.
The metal plate 1 is irradiated with laser light 7 at a distance of ± 0 mm between the focal position and the plate surface of the metal plate 1 on the laser incident side 1a, and the pores 3 are perforated at predetermined positions of the metal plate 1 to form a desired pattern. Was formed. As the laser oscillator of this laser processing machine, a pulse oscillation type was used.

Next, the surface of the metal plate 1 on which the pattern of the pores 3 is formed on the laser beam emitting side 1b is ground by a # 1500 abrasive material, and the periphery of the openings of the pores 3 is polished. A dross 2 was removed. Next, the metal mask for screen printing polished in this manner was held by a holding jig 11 as shown in FIG. 1B, and this was set in a sandblasting grinder. The metal plate 1 was held at an inclination angle θ ₁ = 45 ° with its laser beam emitting side 1b facing upward. On the metal plate 1 held in this way, the metal plate 1
Of the nozzle diameter 4.4 at an inclination angle of θ ₂ = 60 ° with respect to the plate surface
mm blast nozzle 9 is arranged, and the # 600 alumina-based abrasive dispersed in water is discharged from the blast nozzle 9 to 80 mm.
The metal plate 1 was sprayed at a speed of 0 m / sec and sandblasted. In addition, the blast nozzle 9 is the metal plate 1
While moving at a speed of 1 sec / cm ² parallel to the plate surface of the metal plate 1 and changing the spray direction of the granular polishing to the metal plate 1 while maintaining the inclination angle θ ₂ = 60 ° with respect to the plate surface of the metal plate 1. The granular abrasive was sprayed from the top, bottom, left and right directions of the plate 1.

The surface roughness of the wall surface of the pores 3 forming the pattern of the metal plate 1 of the metal mask 1 for screen printing thus obtained was measured and analyzed by a three-dimensional shape analyzer. The degree of Rz was 3.5 μm immediately after the laser processing and before sandblasting.
Was confirmed to be 1.0 μm. It was also confirmed that the melt adhered to the wall surface of the pores 3 was removed at the same time immediately after the laser processing and before sandblasting. Further, the printability of this screen printing metal mask was confirmed by a printing machine. As a result, good passability of the printing paste was confirmed in the pores 3 of 150 μm having the same diameter as the thickness of the metal plate 1.

(Example 2) A similar result was obtained when a metal mask for screen printing was produced in the same manner as in Example 1 except that # 600 carbon sandblast was used as the granular abrasive 10. .

[0020]

As described above, according to the present invention, in the metal mask for screen printing manufactured by the laser processing method, the surface roughness is small and the pores having the wall surface on which the fine melt is not adhered. 3 can be formed. As a result, the printability of the print paste is improved, and the print quality and print accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view of essential parts showing a laser processing step and a sandblast polishing step in a method of manufacturing a metal mask for screen printing according to an example of the present invention.

FIG. 2 is an enlarged vertical cross-sectional side view of essential parts near pores of a metal plate showing a sandblast polishing step in the method for manufacturing a metal mask for screen printing according to the example.

FIG. 3 is an enlarged sectional view of an essential part showing a cross-sectional view of pores of a metal mask for screen printing manufactured according to an example of the present invention.

FIG. 4 is a plan view and a cross-sectional view taken along the line AA of the metal mask for screen printing used in the same example.

FIG. 5 is a cross-sectional pore shape of a metal plate immediately after laser processing of a metal mask for screen printing obtained by a laser processing method, and a cross-sectional shape of pores in a state in which dross is removed by planarly polishing the laser light emission side thereof. FIG.

[Explanation of symbols]

 1 metal plate 1a laser light incident side of metal plate 1b laser light emitting side of metal plate 2 dross 3 pores of metal plate 4 screen frame 5 screen mesh 6 laser head 7 laser light 8 holding jig 9 blast nozzle 10 granular abrasive

Claims (5)

[Claims] 1. A metal mask for screen printing, which is formed by irradiating a metal plate (1) with a laser beam (7) to form a pattern of fine pores (3) on the metal plate (1). In the method, laser light (7) is applied to the metal plate (1).
And then a pattern is formed on the metal plate (1) with fine pores (3), and then a granular abrasive is obliquely applied to the metal plate (1) with respect to the plate surface of the metal plate (1). A method for producing a metal mask for screen printing, which comprises spraying and sandblasting. 2. The metal mask for screen printing according to claim 1, wherein the granular abrasive is sprayed from the surface of the metal plate (1) opposite to the surface irradiated with the laser beam (7). Production method. 3. The method for producing a metal mask for screen printing according to claim 1, wherein the granular abrasive is sprayed onto the metal plate (1) held in an inclined state. 4. The screen printing according to claim 1, wherein the granular abrasive material sprayed onto the metal plate (1) is # 100 to # 1500 alumina-based or carbon-based abrasive. For manufacturing metal masks for automobiles. 5. The spraying speed of the granular abrasive is 400 to 100.
It is 0 m / sec, The manufacturing method of the metal mask for screen printing in any one of Claims 1-4 characterized by the above-mentioned.