JP2003285184A - Machining head of laser beam machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a machining head of a laser beam machine capable of easily enlarging an area of the surface confronting to a material to be machined 3 in a sensing electrode and also capable of providing an opening by approximating a gas passage 17 to a laser machining portion since the sensing electrode is composed of an outer nozzle 12 surrounding the inner nozzle 11. <P>SOLUTION: The machining head 1 has the sensing electrode 5 to measure the distance between a material to be machined 3 and a machining head 1 by detecting capacitance generated among materials to be machined 3, and a guard electrode (supporting member) 6 surrounding the sensing electrode 5. The sensing electrode 5 is composed of the inner nozzle 11 surrounded by the outer nozzle 12, between which the gas passage 17 is formed to blow off spatters generated by laser machining with a manufactured gas blown out of the gas passage 17. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing head of a laser processing machine, and more particularly to a processing head of a laser processing machine provided with a detection electrode for detecting an electrostatic capacitance between the processing head and a workpiece. .

[0002]

2. Description of the Related Art Conventionally, as a processing head of a laser processing machine provided with a detection electrode for detecting an electrostatic capacitance between a processing head and an object to be processed, for example, processing as disclosed in Japanese Utility Model Publication No. 6-46636. The head is known. In the processing head of the above publication, an inner nozzle that irradiates a laser beam is used as the detection electrode, and the capacitance between the inner nozzle and the workpiece is measured while the capacitance is kept constant. By moving the processing head up and down so as to keep it, the distance between the processing head and the workpiece is kept constant. The processing head is provided with a guard electrode surrounding the inner nozzle, and the guard electrode surrounds the detection electrode to electromagnetically shield the detection electrode from the outside, and a gas passage is provided between the inner nozzle and the guard electrode. Is formed. Then, the processing gas is jetted from the jet outlet of the gas passage toward the workpiece to blow out spatter generated during laser processing so that spatter adheres to the inner nozzle and the measurement of capacitance is not unstable. ing.

[0003]

However, in the machining head disclosed in the above publication, the area of the tip of the inner nozzle, that is, the area of the surface facing the workpiece is made large, whereby the workpiece and the machining head are formed. We try to get the capacitance needed to measure the distance. For this reason, it is structurally impossible to provide the ejection port of the gas passage at a position close to the irradiation position of the laser light. As a result, even if the processing gas is blown from the gas passage toward the optical axis of the laser beam and the spatter generated by the laser processing is blown off, the blown spatter adheres to the large surface of the tip of the inner nozzle. In this state, the capacitance between the detection electrode and the workpiece may not be accurately measured, and the distance between the processing head and the workpiece may not be kept constant. is there. In view of the above problems, the present invention is capable of satisfactorily preventing spatter from adhering to the detection electrode, and is capable of stably measuring the distance between the processing head and the workpiece. The head is provided.

[0004]

SUMMARY OF THE INVENTION That is, the present invention is directed to a laser processing machine provided with a detection electrode for detecting an electrostatic capacitance between a processing head and a workpiece and a guard electrode surrounding the detection electrode. In the head, an inner nozzle that is connected to the nozzle body of the processing head via a first insulating member and irradiates a laser beam, and a gas passage that surrounds the inner nozzle and allows a processing gas to flow between the inner nozzle and the inner nozzle. And an outer nozzle surrounding the outer nozzle and connected to the nozzle body to support the outer nozzle via a second insulating member, and the outer nozzle serves as a detection electrode. The support member is a guard electrode.

According to the above structure, since the outer nozzle provided on the outer periphery of the inner nozzle is used as the detection electrode, the surface area of the outer nozzle facing the workpiece is inevitably larger than that of the inner nozzle. ,
Therefore, an area where a sufficient capacitance can be easily obtained can be secured. On the other hand, since the inner nozzle does not require a large area, the gap between the inner nozzle and the outer nozzle, that is, the opening of the gas passage can be provided in the vicinity of the laser beam irradiation port, and compared with the conventional processing head. As a result, it is possible to reduce the risk that spatter that occurs during laser processing adheres to the detection electrode, and thus it is possible to measure the stable distance between the processing head and the workpiece.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Explaining the embodiments shown in the drawings, FIG. 1 shows a sectional view of a processing head 1 of a laser processing machine. The processing head 1 irradiates a laser beam provided in a conventionally known laser processing machine. Is provided in the irradiation unit 2.
The irradiation unit 2 moves the machining head 1 in the front-back, left-right, and up-down directions, and irradiates the workpiece 3 installed below the machining head 1 with laser light to process the workpiece 3. There is. The processing head 1 includes a nozzle body 4 provided in the irradiation unit 2, a detection electrode 5 for detecting the electrostatic capacitance between the processing head 1 and the workpiece 3, and a periphery of the detection electrode 5. And electromagnetically shield the detection electrode 5 from the outside,
A guard electrode 6 is provided to prevent disturbance on the electrostatic capacitance between the detection electrode 5 and the workpiece 3. The detection electrode 5 is composed of a ceramic first insulating member 7 provided between the nozzle body 4 and a ring-shaped second insulating member 8 made of an insulating resin provided between the guard electrode 6. , Is electrically insulated from the nozzle body 4 and the guard electrode 6. Further, the capacitance obtained by the detection electrode 5 is input to a capacitance measuring device (not shown), and this capacitance measuring device measures the distance between the detection electrode 5 and the workpiece 3 from the capacitance. The measurement is performed and the vertical position of the processing head 1 is controlled so that the capacitance is always kept constant, and the distance between the detection electrode 5 and the workpiece 3 is kept constant.

In this embodiment, the detection electrode 5 is
Inner nozzle 11 that emits laser light from its tip
And an outer nozzle 12 surrounding the inner nozzle 11.
The guard electrode 6 includes the inner nozzle 11 and the outer nozzle 12 and the nozzle body 4
It is composed of a support member 6 fixed to the. A cylindrical concave portion 4a is formed on the lower surface of the nozzle body 4,
The first insulating member 7 formed in a cylindrical shape is fitted and positioned in the recess 4a. A cylindrical recess 11a is also formed on the upper surface of the inner nozzle 11, and the cylindrical lower end of the first insulating member 7 is fitted and positioned in the recess 11a. A step portion 11b having a small diameter on the lower tip side is formed at an intermediate height position in the vertical direction on the outer peripheral surface of the inner nozzle 11, and a step portion 12a is also formed on the inner peripheral surface of the outer nozzle 12. Is formed, and the outer peripheral surface and the lower surface of the step 11b of the inner nozzle 11 are the step 1 of the outer nozzle 12.
The inner peripheral surface and the upper surface of 2a are superposed on each other and positioned so that the inner nozzle 11 and the outer nozzle 12 are electrically connected.

Further, a flange portion 12b extending outward is formed at the outer peripheral upper end portion of the outer nozzle 12, that is, at the end portion on the opposite side to the lower tip side, and on the other hand, the supporting member constituting the guard electrode. 6 is formed in a cylindrical shape,
The inner peripheral surface and the flange portion 12 of the outer nozzle 12
A predetermined gap is provided between this and b. Further, a bent portion 6a extending inward is formed at a lower end portion of the support member 6, and the outer nozzle 12 of the outer nozzle 12 is interposed via the ring-shaped second insulating member 8 provided on the upper surface of the bent portion 6a. With the flange portion 12 b supported, the inner peripheral surface of the upper end of the support member 6 is screwed to the lower end portion of the nozzle body 4. At this time, the second insulating member 8 seals the support member 6 and the outer nozzle 12. As described above, since the supporting member 6 supports the flange portion 12b from below by the bent portion 6a, the second insulating member 8, the outer nozzle 12, the inner nozzle 11, and the first insulating member 7 are integrated with the nozzle body 4. Are linked together. Further, the second insulating member 8 is provided between the lower surface of the flange portion 12b and the upper surface of the bent portion 6a, and the outer peripheral surface of the flange portion 12b and the support member 6 are provided.
The outer nozzle 12 and the supporting member 6 can be electrically insulated from each other by providing a gap between the outer nozzle 12 and the inner peripheral surface. From the above, the support member 6 as the guard electrode is electrically connected to the nozzle body 4, and the detection electrode 5 including the inner nozzle 11 and the outer nozzle 12 electrically connected to each other is the above-mentioned first electrode. Insulation member 7
And the second insulating member 8 electrically insulates the nozzle body 4 and the supporting member 6 from each other.

The detecting electrode 5 and the capacitance measuring device (not shown) are connected as follows. That is, the side surface of the nozzle body 4 is provided with a connection terminal 13 for connecting an unillustrated wiring from the capacitance measuring device, and the connection terminal 13 is provided in the cable passage 4b opened on the side surface of the nozzle body 4. Has been inserted. The cable passage 4b is bent at a right angle inside the nozzle body 4 and also opens on the lower surface side so as to communicate with the cable passage 7a formed in the first insulating member 7. A terminal 14 is inserted below the cable passage 7a and the cable passage 4b.
3 and the cable 15 are electrically connected. Above terminal 1
The tip of 4 is in contact with the upper surface of the inner nozzle 11, so that the detection electrode 5 and the capacitance measuring device are electrically connected via these terminals 13 and 14 and the cable 15. become. The capacitance measuring device applies a voltage to the detection electrode 5, and measures the capacitance between the inner nozzle 11 and the outer nozzle 12 as the detection electrode 5 and the workpiece 3. At this time,
The guard electrode (support member) 6 surrounds the detection electrode 5 so that the capacitance between the detection electrode 5 and the workpiece 3 is not disturbed.

Next, the processing head 1 is provided with a gas passage 16 through which the laser light emitted from the irradiation unit 2 and the processing gas flow, and the gas passage 16 is provided in the nozzle body 4 and the first insulation. The inner peripheral surfaces of the member 7 and the inner nozzle 11 are processed, and are tapered so that the diameter is reduced toward the lower end of the inner nozzle 11 about the optical axis of the laser light. Further, a gas passage 17 through which the processing gas flows is also provided on the outer peripheral side of the gas passage 16, and the gas passage 17 is bored inside the nozzle body 4 to connect the side surface and the lower surface thereof. Passage 4
c and a cutout portion 7b provided on the outer periphery of the first insulating member 7 so as to communicate with the gas passage 4c. The gas passage 4c and the cutout portion 7b are provided on the inner periphery of the support member 6. It communicates with the annular space provided on the side. Gas passage 1
The inner nozzle 11 is further provided with a notch 12c provided on the step 12a of the outer nozzle 12.
The cutout portion 12c communicates with a space formed between the inner nozzle 11 and the outer nozzle 12, and the cutout portion 12c surrounds the inner nozzle 11 and is provided at equal intervals. It is supposed to be done. Needless to say, a cutout portion forming a part of the gas passage 17 may be formed on the stepped portion 11b side of the inner nozzle 11. Therefore, the processing gas supplied by the processing gas supply device (not shown) is the same as the nozzle body 4 described above.
From the side of the inner nozzle 1 through the gas passage 17
1 and the outer nozzle 12 through the gap between the workpiece 3
Will be gushed out. At this time, the outer peripheral surface of the tip portion 11c of the inner nozzle 11 is formed into a conical taper shape with a narrowed lower end portion, and the inner peripheral surface and the outer peripheral surface of the tip portion 12d of the outer nozzle 12 are also conical. Since it is formed in a taper shape, the ejection port of the gas passage 16 and the ejection port of the gas passage 17 can be arranged close to each other, and the direction of the processing gas ejected from the gas passage 17 can be changed. The laser beam of the workpiece can be directed to the vicinity of the portion to be processed. Also,
A seal member 18 is provided between the support member 6 and the nozzle body 4 to prevent the gas passage 17 from communicating with the outside.

As can be understood from the above structure, since the detection electrode 5 is composed of the inner nozzle 11 and the outer nozzle 12, the capacitance can be measured not only by the inner nozzle 11 but also by the outer nozzle 12. Therefore, it is possible to obtain a sufficient capacitance required to measure the distance to the workpiece 3. At this time, if the detection electrode 5 is composed of only the outer nozzle 12, the outer nozzle 12 is arranged outside the inner nozzle 11, so that the detection electrode 5 is composed of only the inner nozzle 11. The area of the surface facing the workpiece 3 can be increased as compared with the above, and thus a large capacitance can be easily ensured. A gas passage 17 is provided between the inner nozzle 11 and the outer nozzle 12, and the jet outlet of the gas passage 14 and the jet outlet of the gas passage 17 can be provided in close proximity to each other. 1
Since the direction of the processing gas ejected from 7 can be directed to the portion of the workpiece to be processed by the laser beam, it is possible to effectively prevent the spatter generated during the laser processing from adhering to the nozzle. In addition, since the second insulating member 8 is provided between the flange portion 12b of the outer nozzle 12 and the bent portion 6a of the guard electrode 6, a sufficient gas passage 17 is provided on the inner circumference of the guard electrode 6. At the same time as forming an annular space having a capacitance, the size of the outer shape of the guard electrode 6 can be suppressed, so that the size of the processing head itself can be made compact.

[0012]

As described above, according to the present invention, it is possible to reduce the possibility that the spatter generated during laser processing adheres to the detection electrode as compared with the conventional processing head, and further, the workpiece on the detection electrode is reduced. Since it is possible to secure a large area of the facing surfaces, it is possible to stably measure the distance between the processing head and the workpiece.

[Brief description of drawings]

FIG. 1 is a sectional view of a processing head according to the present embodiment.

[Explanation of symbols]

1 Processing head 3 Workpiece 4 Nozzle body 5 Detection electrode 6 Support member (guard electrode) 7 First insulating member 8 Second insulating member 11 Inner nozzle 12 Outer nozzle 16, 17 Gas passage

Claims (4)

[Claims] 1. A processing head of a laser processing machine, comprising: a detection electrode for detecting an electrostatic capacitance between the processing head and a workpiece; and a guard electrode surrounding the detection electrode, wherein a nozzle body of the processing head. An inner nozzle for irradiating a laser beam, an outer nozzle surrounding the inner nozzle and forming a gas passage for flowing a processing gas between the inner nozzle and the inner nozzle, and the outer nozzle. A supporting member that surrounds the nozzle and is connected to the nozzle body, and that supports the outer nozzle via a second insulating member, and uses the outer nozzle as a detection electrode and the supporting member as a guard electrode. A processing head of a laser processing machine, which is characterized in that 2. The outer peripheral surface of the inner nozzle and the inner peripheral surface of the outer nozzle each have a tapered shape in which the tip side is narrowed, and the gas passage ejects the processing gas toward a processing portion by laser light. The processing head of a laser processing machine according to claim 1, wherein the processing head is a processing head. 3. A step portion having a small diameter on the tip side is formed on the outer peripheral surface of the inner nozzle, and a step portion formed on the inner peripheral surface of the outer nozzle is superposed on the step portion of the inner nozzle so that both are electrically connected. The laser processing machine according to claim 1 or 2, wherein a notch formed in at least one of the stepped portions that are connected to each other forms a part of the gas passage. Processing head. 4. The outer nozzle has a flange portion extending outward at an end portion opposite to the tip side, and the support member has a bent portion extending inward on the tip end side. The flange portion of the outer nozzle is supported by the portion via the second insulating member.
A processing head of the laser processing machine according to claim 3.