JPH11254169A - Laser processing equipment - Google Patents

Abstract

(57) [Problem] To effectively reduce dross and spatter adhering in the vicinity of a processed portion and stably perform high-precision processing even in fine processing of an extremely thin plate. A laser processing apparatus irradiates a workpiece W on a surface plate (a dross removing block 30) from a nozzle 2 and blows an assist gas to a processing point to cut the workpiece W. A cylindrical tip seal member 20 is provided at the tip of the nozzle 2, and the workpiece W is pressed onto the platen by the tip surface 21 of the tip seal member 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing apparatus, and more particularly to a laser processing apparatus for finely cutting a thin plate by a laser beam while blowing an assist gas.

[0002]

2. Description of the Related Art In a cutting process using a laser processing apparatus, an ultra-thin plate (usually 0.3 mm) or the like to be processed is locally and instantaneously melted and cut by a laser beam. Compared to cutting by
Cutting of minute dimensions can be performed with high precision.

A laser processing apparatus utilizes the above-described characteristics to apply a predetermined cutting pattern to a lead frame of a semiconductor device, cut a dam bar connecting outer leads of a lead frame, and attach an electronic component to a printed circuit board. It is used for cutting a metal mask for screen printing used for mounting.

[0004] Since the cutting process using a laser beam is a process utilizing melting by heat input, the melt produced by the process is scattered and adheres to the surface of the ultra-thin plate as spatter, or the melt is aggregated. It is known that it resolidifies and remains on the end face or the like of the portion cut as dross. A large amount of dross and spatter adhere to the vicinity of the end face of the cut portion on the opposite side (hereinafter referred to as the back side) of the workpiece to which the laser beam is irradiated.

If these dross and spatter adhere to the surface of the ultra-thin plate or the processing end face, the processing shape accuracy and dimensional accuracy decrease, and in the case of a lead frame, it becomes a main cause of performance defects such as short circuits. Further, in the case of a metal mask, the shape of the solder pattern is broken, which leads to the occurrence of solder ball defects.

As described above, in a general laser processing apparatus, an assist gas is ejected from a nozzle coaxially with a laser beam, and dross and spatter are blown off according to the ejection flow rate of the assist gas. And adhered to the processing end surface.

In the prior art disclosed in Japanese Patent Application Laid-Open No. 7-124781, the assist gas is spirally ejected from a nozzle to increase the directivity, and the back surface of the workpiece, that is, the surface on which the laser beam is incident, is formed. A solenoid type electromagnetic coil is provided on the opposite side to forcibly remove metal particles that cause dross and spatter from the back side of the processed part of the workpiece by the electromagnetic force of the electromagnetic coil, or liquid is ejected by the liquid ejection means Spraying and washing away to prevent dross and spatter from adhering.

[0008] The structure and operation of the above-mentioned prior art will be described with reference to FIG. In FIG. 7, reference numeral 1 denotes a processing head 1 of a laser processing apparatus. The processing head 1 has a nozzle 2, a condenser lens 3, a protective glass 4, and an assist gas supply port 5. The laser beam L is focused on the surface of the workpiece W by the focusing lens 3.

On the back side of the workpiece W, a dross removing device 6 is provided.
Are arranged to face the nozzle 2. In the dross removing device 6, a cylindrical solenoid coil 8 having a through hole 7 in the center axis direction is arranged concentrically with respect to the nozzle 2. The solenoid coil 8 is supplied with a direct current to apply a magnetic field (magnetic field) in a direction away from the workpiece in the central axis direction. By this magnetic field, electromagnetic force acts on metal particles that cause dross and spatter generated by laser processing, and is forcibly separated from the back surface of the processed part,
Removed.

The dross removing device 6 has a liquid ejection port 9 and a liquid supply port 10 formed therein. The liquid supplied to the dross removing device 6 from the liquid supply port 10 is filled around the solenoid coil 8 and is ejected from the liquid ejection port 9 to be sprayed from below onto the processing position of the workpiece W. By this liquid spray, the remaining metal particles generated by the laser processing are washed away.

Further, since the assist gas supply port 5 is displaced from the center of the nozzle, the assist gas is ejected from the nozzle 2 in a spiral shape. As a result, the directivity of the assist gas flow is enhanced, the metal particles are easily blown off, and the adhesion of dross and spatter is reduced.

[0012]

In recent years, in order to cope with high-density mounting and high integration of a semiconductor chip, it is required to reduce the pitch of the lead frame and increase the number of pins. The pitch of the metal mask pattern is also being narrowed. For this reason, in the processing technique for processing a metal plate as described above, it is required to perform finer processing, and a thin material having a plate thickness of about 0.1 to 0.2 mm has a groove width of 0.1 to 0.2 mm. It must be cut at about 03 mm.

[0013] The processing method using a laser beam enables fine and high-precision processing, but since the groove width is about 1/5 narrower than that of conventional sheet metal processing, it is ejected from a nozzle coaxially with the laser beam. With the assist gas, it is difficult for the gas to flow into the cut groove, and it is inevitable that dross and spatter remain and adhere to the workpiece after processing.

In the prior art as disclosed in Japanese Patent Application Laid-Open No. 7-124781, the removal of dross and spatter is improved to some extent, but when the width of the cut groove becomes narrower as described above, the directivity of the assist gas is reduced. Despite the increase, the outflow of assist gas into the gap between the nozzle and the workpiece is inevitable. Therefore, the molten metal cannot be effectively blown off to the back surface, and the effect of removing dross and spatter after processing is reduced.

If the assist gas pressure is increased in order to increase the effect, the workpiece is bent by the assist gas pressure, and the bending shifts the focal position of the laser, so that stable processing cannot be performed. Further, when the workpiece is a non-magnetic material such as stainless steel or copper alloy, there is a problem that the electromagnetic force does not act on the metal powder and the material of the workpiece is limited.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and effectively reduces dross and spatter adhering to the vicinity of a processed portion in fine processing of a workpiece, particularly, an extremely thin plate. It is another object of the present invention to obtain a laser processing apparatus that stably performs high-precision processing.

[0017]

To achieve the above object, a laser processing apparatus according to the present invention irradiates a workpiece on a surface plate with a laser beam from a nozzle, and blows an assist gas to a processing point, In the laser processing apparatus for cutting the workpiece, a cylindrical tip seal member is provided at the tip of the nozzle, and the workpiece is pressed onto the surface plate by the tip face of the tip seal member.

In the laser processing apparatus according to the next invention, the tip seal member is mounted on the tip of the nozzle by a screw structure so that the mounting height can be adjusted.

In the laser processing apparatus according to the next invention, a center hole is formed on the surface plate concentrically with the nozzle, and a knife edge portion is formed around the center hole.

In the laser processing apparatus according to the next invention, the knife edge portion is provided by a knife edge member separate from the surface plate, and the knife edge member is exchangeably mounted on the surface plate. .

In the laser processing apparatus according to the next invention, the platen is constituted by a suction type dross removing block, and a radial suction groove is formed on a block surface against which a workpiece is pressed.

A laser processing apparatus according to the next invention has a cooling gas supply means for supplying a cooling gas to the intake groove.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a laser processing apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. In the embodiments of the present invention described below, the same components as those of the above-described conventional example are denoted by the same reference numerals as those of the above-described conventional example, and description thereof will be omitted.

Embodiment 1 1 to 5 show a first embodiment of a laser processing apparatus according to the present invention. A screw 2a is engraved on the outer periphery of the tip of the nozzle 2, and the screw 2a
A tip seal member 20 having a bottomed cylindrical shape is screwed and mounted so that the mounting height can be adjusted.

The lower bottom surface (tip surface) 21 of the chip seal member 20 is the upper surface 3 of the dross removing block 30 forming a surface plate.
1 is pressed against the upper surface of an ultra-thin plate (workpiece) W which is fed and moved under a predetermined tension, and this pressing causes the ultra-thin plate W to move to the upper surface 31 of the dross removing block 30.
Pressed to.

An opening 22 having an appropriate diameter through which the laser beam L and the assist gas pass is formed in the lower bottom surface portion 21 of the tip seal member 20 at a position concentric with the nozzle 2. Note that structurally, the tip seal member 20 can be formed integrally with the tip of the nozzle 2.

The dross removing block 30 has a central hole 32 formed in the upper surface 31 at a position concentric with the nozzle 2. A central hole 32 is formed in the upper surface of the dross removing block 30.
A ring-shaped knife edge member 40 is fitted so as to be exchangeable and concentrically. The knife edge member 40 is made of cemented carbide or steel and has a block upper surface 31.
An annular knife edge portion 41 is formed around the central hole 32 in a concentric manner.

The dross removing block 30 is of a suction type. The dross removing block 30 is provided with a suction port 33 communicating with the central hole 32, and the suction port 33 is connected to a vacuum pump (not shown). . On the upper surface 31 of the dross removing block 30 and on the upper surface of the knife edge member 40 flush with the upper surface 31, a plurality of intake grooves 34 are formed radially around the central hole 32.

The laser oscillator, the processing head and the like may have the same configuration as those conventionally known.

Next, the operation of the laser processing apparatus having the above configuration will be described. A laser beam L is incident on a condenser lens 3 in the processing head 1 from a laser oscillator (not shown), and the laser beam L condensed by the condenser lens 3 is irradiated so as to focus on the ultrathin plate W. .
Thereby, the ultrathin plate W pressed against the upper surface 31 of the dross removing block 30 by the lower bottom surface portion 21 of the chip seal member 20 is locally and instantaneously melted to form a processed portion (opening) A. In this state, the processing proceeds by moving the ultrathin plate W relative to the processing head 1.

The assist gas ejected coaxially with the laser beam L passes through the tip seal member 20 attached to the tip of the nozzle 2, and almost all of it flows into the processing portion A of the ultra-thin plate W through the opening 22. , Flows out to the back surface of the ultra-thin plate W through the processing portion A. As a result, the melt generated by the melting of the processing portion A is blown off and removed, and the dross and spatter adhere to the ultrathin plate W are suppressed by the minimum assist gas.

The ultra-thin plate W is a dross removing block 30.
Is pressed against the upper surface 31 of the super thin plate W, no bending occurs due to the ejection pressure of the assist gas in the ultrathin plate W. Thereby, the focal position of the laser beam L does not change, and fine and highly accurate processing is stably performed.

Further, since the assist gas is oxygen, the combustion of the processed portion A of the ultra-thin plate W by the irradiation of the laser beam L is assisted.

When the pressing force is adjusted by vertically moving the processing head 1 itself, the focal point of the laser beam L on the surface of the workpiece moves, but the tip seal member 20 is attached to the nozzle 2 by the screw 2a. Since the tip seal member 20 is mounted so as to be adjustable, the force for pressing the ultra-thin plate W against the upper surface 31 of the dross removing block 30 can be adjusted without moving the focal position by moving the tip seal member 20 up and down.

Even if dross remains on the back surface of the processing portion A,
When the ultra-thin plate W moves on the upper surface 31 of the dross removing block 30, the residue on the back surface is scraped off by the knife edge portion 41 and rides on the air suction flow from the suction port 33 connected to the vacuum pump. Thus, it is sucked and removed into the central hole 32 in a negative pressure state. Thereby, high quality processing is performed.

Since the knife edge member 40 is replaceably mounted on the dross removing block 30 as a surface plate, the knife edge portion 41 can be replaced in a short time.

Further, since the central hole 32 is in a negative pressure state, the dross removing block 3 is formed in the intake groove 34.
0, an air flow from the outer peripheral side toward the central hole 32 is generated,
By this air flow, the back surface of the processing portion is cooled, and the assist gas is prevented from flowing around the back surface of the processing portion,
Spatter scattering and adhesion and dross adhesion are suppressed. This also enables high quality processing.

Embodiment 2 FIG. 6 shows a second embodiment of the laser processing apparatus according to the present invention. FIG.
In the figure, the portions corresponding to those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and the description thereof is omitted.

In this embodiment, a ring-shaped gas supply groove 42 is formed in the upper part of the outer periphery of the dross removing block 30. The gas supply groove 42 has its upper groove opening closed by placing the ultra-thin plate W on the dross removing block 30, and communicates with the opening on the outer peripheral side of each intake groove 34. A manifold passage for supplying gas to 34 is provided.

A gas supply port 43 is formed in the gas supply groove 42, and the gas supply port 43 is connected to an inert high-pressure gas cylinder 44 such as N 2 and a cooling gas supply means using a gas cooler 45.

With the above-described configuration, the inert gas in the inert high-pressure gas cylinder 44 is cooled by the gas cooler 45, and is supplied as a low-temperature cooling gas from the gas supply port 43 to the gas supply groove 4.
2 is supplied. The low-temperature inert gas supplied to the gas supply groove 42 is supplied to each intake groove 34, and is supplied to the intake groove 3.
4 from the outer peripheral side of the dross removing block 30 to the central hole 3.
Flow to side 2.

As a result, a flow of a low-temperature inert gas is generated on the back surface of the processed portion.
The back surface of the processed portion is forcibly cooled, and accordingly, spatter and dross are also cooled before adhering to the ultrathin plate W. As a result, spatter adhesion and dross adhesion are effectively suppressed.

In order to obtain an effective cooling effect, the gas supplied to the intake groove 34 is optimally an inert gas which does not react thermally. However, depending on the required cooling effect, the gas supplied to the intake groove 34 is optimal. The gas supplied to 34 may be cooled compressed air.

[0044]

As will be understood from the above description, according to the laser machining apparatus of the present invention, the workpiece is pressed onto the surface plate by the tip end surface of the tip seal member provided at the tip end of the nozzle. Even when the groove width becomes narrow, most of the assist gas ejection pressure acts in the cutting groove, and the molten metal can be effectively blown off from the back surface, and the adhesion of dross and spatter can be prevented with the minimum assist gas, High quality processing can be performed economically. Also, since the bending due to the assist gas ejection pressure does not occur even in the processing of an extremely thin plate, the focus position does not change, and fine and high-precision processing can be stably performed.

According to the laser processing apparatus of the next invention, the workpiece such as an ultra-thin plate is placed on the surface plate without changing the focal position of the laser beam by adjusting the mounting height position of the chip seal member by the screw structure. The pressing force can be easily adjusted, and this adjustment work time can be shortened.

According to the laser processing apparatus of the next invention, dross or spatter adhering to the end surface (back surface) of the cut portion by the knife edge formed on the platen against which the workpiece is pressed when the workpiece is moved. Is scraped off, so that high-quality processing is performed.

According to the laser processing apparatus of the next invention, the knife edge portion is provided by a knife edge member separate from the surface plate, and the knife edge member is exchangeably mounted on the surface plate. Exchange of parts can be performed in a short time.

According to the laser processing apparatus of the next invention, the air flows through the intake groove formed on the block surface against which the workpiece is pressed, which is constituted by the suction type dross removing block forming the surface plate. By this air flow, the back surface of the processing portion is cooled, the assist gas is prevented from wrapping around the back surface of the processing portion, spatter scattering / adhesion and dross adhesion are suppressed, and high quality processing is performed.

According to the laser processing apparatus of the next invention, since the cooling gas is supplied to the intake groove by the cooling gas supply means, the back surface of the processing portion is cooled strongly, and spatter and dross adhere to the extremely thin plate. Before the cooling, the deposition of spatter and dross is effectively suppressed, and high-quality processing is performed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing Embodiment 1 of a laser processing apparatus according to the present invention.

FIG. 2 is a perspective view of a chip seal member used in the laser processing apparatus according to the present invention.

FIG. 3 is an enlarged top view of a dross removing block used in the laser processing apparatus according to the present invention.

FIG. 4 is a sectional view taken along line IV-IV in FIG. 3;

FIG. 5 is an enlarged sectional view of a main part showing a gas flow in the laser processing apparatus according to the present invention.

FIG. 6 is a sectional view showing Embodiment 2 of the laser processing apparatus according to the present invention.

FIG. 7 is a cross-sectional view of a conventional laser processing apparatus.

[Explanation of symbols]

1 processing head, 2 nozzles, 2a screw, 3 condenser lens, 4 protective glass, 5 assist gas supply port, 20
Tip seal member, 21 Lower bottom part, 22 opening, 30
Dross removing block, 31 Upper surface, 32 Central hole, 3
3 suction port, 34 intake groove, 40 knife edge member, 41 knife edge part, 42 gas supply groove, 44
Inert high pressure gas cylinder, 45 gas cooler, L laser beam, W ultra thin plate.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hirokazu Miyakawa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (6)

[Claims] 1. A laser processing apparatus that irradiates a workpiece on a surface plate with a laser beam from a nozzle, blows an assist gas to a processing point, and cuts the workpiece, wherein a cylindrical tip is provided at a tip of the nozzle. A laser processing apparatus provided with a seal member, wherein the workpiece is pressed onto the surface plate by a tip end surface of the tip seal member. 2. The laser processing apparatus according to claim 1, wherein the tip seal member is mounted on a tip of the nozzle so that a mounting height can be adjusted by a screw structure. 3. The laser processing according to claim 1, wherein a center hole is formed on the surface plate concentrically with the nozzle, and a knife edge portion is formed around the center hole. apparatus. 4. The knife edge member is provided by a knife edge member separate from the surface plate, and the knife edge member is exchangeably mounted on the surface plate. Laser processing equipment. 5. The platen according to claim 1, wherein the platen is formed of a suction type dross removing block, and a radial intake groove is formed on a block surface against which a workpiece is pressed. The laser processing apparatus according to any one of the above. 6. The laser processing apparatus according to claim 5, further comprising cooling gas supply means for supplying a cooling gas to the intake groove.