JP2008036663A - Laser beam cutting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam cutting device capable of preventing a workpiece from being damaged by a residual stuff such as a dross generated in a cut part. <P>SOLUTION: The laser beam cutting device 1 has a machining head 2 on the upper side and a machining stand 3 on the lower side across a workpiece W such as a metal plate. Laser beams L are applied from a nozzle 12 of the machining head having a condensing lens 11, and an assist gas is jetted, and the assist gas is sucked on the machining stand 3 side through its center hole. The machining stand 3 has a lower holder 26 on an upper end located immediately below the workpiece W. A hermetic internal space with its upper face part being closed by a lid member 32 formed of a porous material is formed in the lower holder 26, and air is blown to the workpiece W located above from the lid member 32 by feeding compressed air into the internal space. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser cutting device that cuts a workpiece such as an ultrathin metal plate with a laser beam, and more particularly to a laser cutting device that prevents a workpiece from being damaged by residues such as dross generated at a cutting portion.

  Laser beam cutting is a process that uses melting by heat input, so that the melt generated during the process scatters and adheres to the work surface such as an ultra-thin metal plate as a spatter, or the melt aggregates. Then, it solidifies again and remains on the end face of the part cut as dross. Such dross and spatter often adhere to the vicinity of the end surface of the cut portion on the surface opposite to the surface irradiated with the laser beam (hereinafter referred to as the back surface side). In view of this, Japanese Patent Application Laid-Open No. 11-254169 discloses a technique for effectively reducing dross and spatter adhering to the vicinity of a processed portion by blowing off dross and spatter by an assist gas ejected coaxially with a laser beam. There has been proposed a laser cutting apparatus that stably performs processing. FIG. 5 is a cross-sectional view showing the laser cutting device described in the publication.

  In this laser cutting device, laser light L is incident on a condensing lens 102 in a machining head 101 from a laser oscillator (not shown), and the laser light L condensed by the condensing lens 102 is an ultrathin metal plate workpiece W. Irradiate to focus on. The work W is cut when the portion irradiated with the laser beam L is melted and the work W itself moves relative to the processing head 101. The assist gas ejected coaxially with the laser beam L is blown to the workpiece W through the chip seal member 110 that presses the workpiece W, and flows out to the back surface of the workpiece W through the cutting portion A. As a result, the melt produced by melting the cutting part A is blown away and the dross and spatter are prevented from adhering to the workpiece W.

In this laser cutting apparatus, even if dross or the like remains on the back surface of the cutting part A, the work W moves on the upper surface 121 of the support block 120 as shown in FIG. The part 122 is scraped off. The suction port 125 is connected to a vacuum pump, and the inside of the central hole 124 is in a negative pressure state by the air suction flow, so that the scraped residue is removed by suction. Further, a plurality of intake grooves 126 are formed radially on the upper surface of the support block 120 and the knife edge member 123 with the central hole 124 as the center. Therefore, if the central hole 124 is in a negative pressure state, an air flow toward the central hole 124 is generated in the intake concave groove 126, thereby cooling the back surface of the cut portion and preventing the assist gas from flowing around the back surface. As a result, spatter scattering and adhesion and dross adhesion are suppressed.
JP-A-11-254169 JP 2002-79390 A

  By the way, in the conventional laser cutting device, residues such as dross adhering to the back surface of the workpiece are scraped off by the knife edge portion 122 and are mostly discharged from the central hole 124 under a negative pressure. An object enters between the work W and the support block 120 that are pressed against each other. Then, the residue bitten in the meantime rubs and the work W is scratched. Therefore, for example, Japanese Patent Application Laid-Open No. 2002-79390 has proposed that a felt or a sliding plate is provided on the upper surface of the support block with which the workpiece W comes into contact so that the workpiece W can be easily slid and the workpiece W is not damaged. . However, even in such a case, it was not possible to prevent the workpiece W from being damaged by the residue sandwiched between the sliding surfaces.

  Accordingly, an object of the present invention is to provide a laser cutting apparatus in which a workpiece is not damaged by a residue such as dross generated in a cutting portion in order to solve such a problem.

  The laser cutting device according to the present invention irradiates a laser beam from a nozzle of a processing head provided with a processing head on the upper side and a processing table on the lower side with a workpiece such as a metal plate and a condenser lens, and injects an assist gas. On the processing table side, the assist gas is sucked through the center hole, and the processing table has a lower holder at an upper end portion located immediately below the workpiece, and the lower holder Is an airtight internal space whose upper surface is closed with a porous lid member, and compressed air is supplied to the internal space so that air is blown out to the upper workpiece through the lid member. It is characterized by being.

In the laser cutting device of the present invention, it is preferable that the lower holder is formed by fitting the annularly formed lid member into an annular groove formed around the center hole.
In the laser cutting device of the present invention, it is preferable that the lower holder is attached so as to be movable in the vertical direction and supported from below by a spring.

  Therefore, according to the laser cutting device of the present invention, since air is blown out from the lid member to create an air layer between the workpiece, the residue removed from the workpiece is caught between the workpiece and the lower holder. No more rolling or rubbing. Therefore, the workpiece W after being cut by the laser beam can be processed with high dimensional accuracy so as not to be damaged.

Next, an embodiment of a laser cutting apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a laser cutting device of the present embodiment.
The laser cutting device 1 is configured so that a laser beam L is sent from a laser oscillator (not shown) via a reflection mirror to a processing head 2 that cuts a workpiece W of an ultrathin metal plate. A processing table 3 is provided above the workpiece W and below the workpiece W.

  The processing head 2 is formed in a cylindrical shape, and a condensing lens 11 that condenses the laser light L is provided in the middle of the center hole, and a nozzle 12 is provided at the lower end. Further, in order to inject assist gas into the lower part of the condenser lens 11, the joint 18 is fixed to the port 13 penetrating the side part and connected to a gas supply device (not shown). The nozzle 12 is formed with a diameter of, for example, 1.0 mm or less so that the assist gas in the processing head 2 flows intensively into the cutting portion of the workpiece W.

  The nozzle 12 is fixed to a cylindrical lower block 14 constituting the processing head 2. A cylindrical upper holder 15 is attached to the lower end flange portion of the lower block 14 so as to surround the nozzle 12, and the workpiece W is easily slid and scratched on the inner side of the lower end thereof. A sliding material 16 is attached to prevent the slippage. The sliding material 16 is formed so that the height of the front end surface in contact with the workpiece W coincides with the condensing point of the laser light L condensed by the condensing lens 11.

  On the other hand, the processing table 3 disposed under the workpiece W is formed in a cylindrical shape so as to have a center hole in order to suck the assist gas sent from the processing head 2 side. The processing table 3 is provided with a cylindrical adjustment nut member 22 that is rotatable with respect to the base 21. The adjusting nut member 22 is internally threaded and has a flange 22a at the lower end. The flange portion 22 a is fitted into a circular recess formed on the upper surface of the base 21, and a drop prevention plate 28 is covered on the upper side. Therefore, the adjustment nut member 22 is rotatably attached in a state where movement in the vertical direction is restricted. A cylindrical scale tube 22b is fixed to the adjusting nut member 22 as shown in FIG.

  A vertical adjustment pipe 23 is disposed inside the adjustment nut member 22, and a male screw formed on the outer periphery of the adjustment nut member 22 is screwed with a female screw of the adjustment nut member 22. The vertical adjustment pipe 23 is a cylindrical member having a lower end fitted into the base 21, and a thick portion formed at the upper portion is loaded with springs 24 in a plurality of recesses formed at the upper end. . As shown in FIG. 3, an axial groove 23 a is formed at the lower end portion of the vertical adjustment pipe 23, and the tip of an anti-rotation pin 25 fixed to the base 21 is inserted therein. Therefore, the adjustment nut member 22 rotates so that the vertical adjustment pipe 23 can move only in the vertical direction (axial direction) without rotating together.

  A lower holder 26 is provided above the vertical adjustment pipe 23 and positioned by inserting a cylindrical portion into the through hole. The lower holder 26 is formed by fixing a holder portion 26b on a support portion 26a composed of a cylindrical portion inserted into the vertical adjustment tube 23 and an upper flange portion. An axial groove is formed in the cylindrical portion of the support portion 26a, and the tip of an anti-rotation pin 27 fixed to the thick portion of the vertical adjustment tube 23 is inserted therein.

  The holder portion 26 b that constitutes the lower holder 26 is a member in which an annular groove 31 that opens upward is formed, and an annular lid member 32 is fitted so as to close the annular groove 31. An airtight space is formed in the annular groove 31 closed by the lid member 32, and a joint 34 for supplying compressed air to a port 33 formed through the side surface portion is formed in the holder portion 26b. It is fixed. An air hose for supplying compressed air from an air pump (not shown) is connected to the joint 34. The lid member 32 that closes the annular groove 31 is formed of a porous sintered metal, ceramics, or the like so that the compressed air supplied into the airtight space of the annular groove 31 is blown upward.

  Next, in the laser cutting device of this embodiment, rotation is given to the adjustment nut member 22 through the scale tube 22b. Thereby, the vertical adjustment tube 23 screwed by the female screw and the male screw moves in the vertical direction, and at the same time, the lower holder 26 also moves to adjust the height. The workpiece W is sandwiched between the lower holder 26 and the upper holder 15. The workpiece W is arranged on an XY stage (not shown), and movement control is performed based on preset cutting data, and laser cutting is performed according to a predetermined shape. A suction tube 4 as shown in FIG. 3 is connected to the suction hole 30 of the processing table 3 between a suction device (not shown), and the suction hole 30 and the suction tube 4 have a negative pressure during processing. .

For cutting the workpiece W by the laser beam, focusing is performed so that the laser beam L emitted from a laser oscillator (not shown) is condensed on the surface of the workpiece W by the condenser lens 11 via the reflection mirror. The machining head 2 can move up and down, descends after the work W is installed, and the sliding material 16 is applied from above. Below, as described above, the lower holder 26 of the processing table 3 is adjusted up and down, and positioned so that the upper surface of the lid member 32 contacts the workpiece W.
And at the time of a cutting process, assist gas is injected in the process head 2 with a high pressure. The workpiece W is melted locally and instantaneously by the heat input of the laser beam, and predetermined cutting is performed by the set movement.

  The assist gas flows through the cutting portion of the workpiece W into the suction hole 30 of the processing table 3 and is drawn into the suction pipe 4 that is at a negative pressure. A melt such as dross generated along with the cutting of the workpiece W is drawn to the suction pipe 4 and discharged by the flow of the assist gas. However, as shown in FIG. 4, a part of the dross attached to the back surface of the workpiece W in a protruding shape remains as a residue D. Here, FIG. 4 is an enlarged cross-sectional view showing the positional relationship between the workpiece W and the lower holder 26. In the laser cutting device 1 of the present embodiment, compressed air is supplied from an air pump (not shown) to the lower holder 26 during processing. The compressed air is supplied from the joint 34 to an airtight space of the annular groove 31 formed in the lower holder 26, and creates a flow as shown by a wavy arrow in the figure.

That is, the compressed air sent into the lower holder 26 is blown out from the airtight annular groove 31 through the porous lid member 32 toward the upper workpiece W, and the air generated between the workpiece W and the lid member 32 is air. Create a layer. Then, the air blown out from the lid member 32 flows into the suction hole 30 having a negative pressure, and is drawn into the suction pipe 4 in the same manner as the assist gas.
Accordingly, the residue D adhering to the lower end of the workpiece W is peeled off by the air flow and discharged from the suction hole 30. Even if the peeling does not fall off, if the amount of protrusion of the residue D is smaller than that of the air layer between the workpiece W and the lid member 32, the lower holder 26 passes without interference. When the protrusion amount of the residue D is larger than the air layer, the upper end portion of the suction hole 30 of the lower holder 26 hits and the residue D is scraped off. At that time, since the air blown out from the lid member 32 flows into the suction hole 30, the residue D is discharged through the suction hole 30 together with the air.

Therefore, according to the laser cutting device 1 of the present embodiment, since the air layer is blown out from the lid member 32 to form an air layer between the workpiece W, the residue D that has come off the workpiece W is There is no longer any rolling or rubbing between the workpiece W and the lower holder 26. Therefore, the workpiece W after being cut by the laser beam L can be processed with high dimensional accuracy so as not to be damaged.
In the laser cutting device 1 of the present embodiment, even if the distance between the workpiece W and the upper surface of the lower holder 26 varies due to the deflection of the workpiece W, the spring 24 that supports the lower holder 26 is deformed and adjusted, An air layer is stably formed between the two as shown in FIG.

  Although one embodiment of the laser cutting device according to the present invention has been described above, the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention.

It is sectional drawing which showed one Embodiment of the laser cutting device. It is the side view which showed the processing stand of the laser cutting device. It is sectional drawing which showed the process base lower part of the laser cutting device. It is the expanded sectional view which showed the positional relationship of a workpiece | work and a lower holder. It is sectional drawing which showed the conventional laser cutting device. It is a partial expanded sectional view of the conventional laser cutting device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser cutting device 2 Processing head 3 Processing stand 11 Condensing lens 12 Nozzle 16 Sliding material 21 Base 22 Adjustment nut member 23 Vertical adjustment pipe 26 Lower holder 31 Annular groove 32 Cover member

Claims (3)

A processing head is provided above the workpiece such as a metal plate, a processing base is provided below, a laser beam is emitted from a nozzle of the processing head provided with a condenser lens, and an assist gas is injected. In the laser cutting device configured to suck the assist gas through the center hole,
The working table has a lower holder at the upper end located directly below the workpiece, and the lower holder has an airtight inner space in which the upper surface is closed by a lid member made of a porous material. A laser cutting device characterized in that air is blown out to an upper workpiece through a lid member by supplying compressed air. In the laser cutting device according to claim 1,
The laser cutting apparatus according to claim 1, wherein the lower holder is formed by fitting the lid member formed in an annular shape into an annular groove formed around the center hole. In the laser cutting device according to claim 1 or 2,
The laser cutting apparatus according to claim 1, wherein the lower holder is attached in a state in which the lower holder can be moved in the vertical direction and is supported from below by a spring.

Images