JP4054964B2 - Laser processing machine head - Google Patents

Description

[0001]
BACKGROUND 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 that detects a capacitance between the processing head and a workpiece.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a processing head of a laser processing machine provided with a detection electrode that detects a capacitance between a processing head and a workpiece, for example, a processing head as disclosed in Japanese Utility Model Publication No. 6-46636 is known. Yes.
In the processing head of the above publication, an inner nozzle that emits laser light is used as the detection electrode, and this capacitance is kept constant while measuring the capacitance between the inner nozzle and the workpiece. By moving the machining head up and down so as to keep it, the distance between the machining head and the workpiece is kept constant.
The processing head is provided with a guard electrode surrounding the inner nozzle. The guard electrode surrounds the detection electrode and electromagnetically shields the detection electrode from the outside, and a gas passage between the inner nozzle and the guard electrode. Is forming. Then, spatter generated during laser processing is blown off by jetting the processing gas from the gas passage outlet toward the workpiece, so that the spatter adheres to the inner nozzle and the capacitance measurement does not become unstable. ing.
[0003]
[Problems to be solved by the invention]
However, in the machining head in the above publication, the area of the tip of the inner nozzle, that is, the area of the surface facing the workpiece is formed large, and thereby it is necessary to measure the distance between the workpiece and the machining head. Capacitance is obtained. For this reason, it is structurally impossible to provide the jet outlet of the gas passage at a position close to the irradiation position of the laser beam.
As a result, even if the processing gas is blown from the gas path toward the optical axis of the laser beam and the spatter generated by the laser processing is blown away, there is a risk that the spatter blown off 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 machining head and the workpiece may not be kept constant. is there.
In view of the problems as described above, the present invention can satisfactorily measure the distance between the machining head and the workpiece so as to satisfactorily prevent spatter from adhering to the detection electrode. The head is provided.
[0004]
[Means for Solving the Problems]
That is, the present invention relates to a processing head of a laser processing machine including a detection electrode that detects a capacitance between a processing head and a workpiece, and a guard electrode that surrounds the detection electrode.
An inner nozzle that is disposed on the lower surface of the nozzle body of the processing head via a first insulating member and irradiates a laser beam, and surrounds the inner nozzle and is formed on the lower surface of the step portion formed on the outer peripheral surface of the inner nozzle. An outer nozzle that is polymerized and has a gas passage for passing a processing gas between the inner nozzle and the outer nozzle. The outer nozzle surrounds the outer nozzle and is connected to the nozzle body. A support member for supporting the nozzle from below ,
By connecting the support member to the nozzle body, the second insulating member, the outer nozzle, the inner nozzle and the first insulating member are supported from below by the support member and integrally connected to the nozzle body.
The outer nozzle is a detection electrode, and the support member is a guard electrode.
[0005]
According to the above configuration, 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, and therefore easy. It is possible to secure an area where a sufficient capacitance can be obtained.
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 light irradiation port, compared with the conventional processing head. Thus, it is possible to reduce the possibility that spatter generated during laser processing adheres to the detection electrode, thereby making it possible to measure a stable distance between the processing head and the workpiece.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The illustrated embodiment will be described below. FIG. 1 shows a cross-sectional view of a processing head 1 of a laser processing machine. ing. The irradiation unit 2 moves the processing head 1 back and forth, right and left, and up and down, and irradiates the workpiece 3 placed below the processing head 1 with laser light to process the workpiece 3. Yes.
The processing head 1 surrounds the periphery of the detection electrode 5, a nozzle body 4 provided in the irradiation unit 2, a detection electrode 5 for detecting the capacitance between the processing head 1 and the workpiece 3. Thus, the detection electrode 5 is electromagnetically shielded from the outside, and the guard electrode 6 is provided so as not to disturb the electrostatic capacitance between the detection electrode 5 and the workpiece 3. The detection electrode 5 is formed by 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. The nozzle body 4 and the guard electrode 6 are electrically insulated.
The capacitance obtained by the detection electrode 5 is input to a capacitance measuring device (not shown). The capacitance measuring device determines the distance between the detection electrode 5 and the workpiece 3 from the capacitance. By measuring and controlling the vertical position of the machining head 1 so that the capacitance is always kept constant, the distance between the detection electrode 5 and the workpiece 3 is kept constant.
[0007]
In this embodiment, the detection electrode 5 is composed of an inner nozzle 11 that irradiates laser light from its tip, and an outer nozzle 12 that surrounds the inner nozzle 11, and the guard electrode 6 is the inner nozzle 11. And the outer nozzle 12 are constituted by a support member 6 that fixes the nozzle body 4 to the nozzle body 4.
A cylindrical recess 4a is formed on the lower surface of the nozzle body 4, and 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 end 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. The outer peripheral surface and the lower surface of the step portion 11b of the inner nozzle 11 are respectively overlapped with the inner peripheral surface and the upper surface of the step portion 12a of the outer nozzle 12, and both are positioned, and the inner nozzle 11 and The outer nozzle 12 is electrically connected.
[0008]
Further, a flange portion 12b extending outward is formed at the outer peripheral upper end of the outer nozzle 12, that is, at the end opposite to the lower tip side, while the support member 6 constituting the guard electrode is a cylinder. A predetermined gap is provided between the inner peripheral surface of the outer nozzle 12 and the flange portion 12 b of the outer nozzle 12.
Further, a bent portion 6a extending inward is formed at the lower end portion of the support member 6, and the outer nozzle 12 is interposed via the ring-shaped second insulating member 8 provided on the upper surface of the bent portion 6a. The upper end inner peripheral surface of the support member 6 is screwed to the lower end portion of the nozzle body 4 while the flange portion 12b is supported. At this time, the second insulating member 8 seals the support member 6 and the outer nozzle 12.
Thus, since the support 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 connected to each other.
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 a gap is provided between the outer peripheral surface of the flange portion 12b and the inner peripheral surface of the support member 6. Thus, the outer nozzle 12 and the support member 6 can be electrically insulated from each other.
From the above, the support member 6 as a 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 that are electrically connected to each other is the first electrode. The insulating member 7 and the second insulating member 8 are electrically insulated from the nozzle body 4 and the support member 6.
[0009]
And the said detection electrode 5 and the electrostatic capacitance measuring apparatus which is not shown in figure are connected as follows.
That is, a connection terminal 13 for connecting a wiring (not shown) from the capacitance measuring device is provided on the side surface of the nozzle body 4, and the connection terminal 13 is provided in the cable passage 4 b 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 is also opened 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 7 a and the cable passage 4 b, and the terminal 14 is electrically connected to the connection terminal 13 and the cable 15.
The tip of the terminal 14 is in contact with the upper surface of the inner nozzle 11. Therefore, the detection electrode 5 and the capacitance measuring device are electrically connected to these terminals 13 and 14 via the cable 15. Become so.
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 as not to disturb the electrostatic capacitance between the detection electrode 5 and the workpiece 3.
[0010]
Next, the processing head 1 is provided with a gas passage 16 through which the laser light irradiated from the irradiation unit 2 and the processing gas are circulated. The gas passage 16 includes the nozzle body 4, the first insulating member 7 and the gas passage 16. The inner nozzle 11 is processed into an inner peripheral surface and is tapered so that the diameter decreases toward the lower end of the inner nozzle 11 around the optical axis of the laser beam.
Further, a gas passage 17 through which the processing gas flows is provided on the outer peripheral side of the gas passage 16, and the gas passage 17 is formed in the nozzle body 4 to communicate the side surface and the lower surface. A passage 4c and a notch 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 notch 7b are formed in the support member 6. It communicates with an annular space provided on the circumferential side.
The gas passage 17 is further communicated with a space formed between the inner nozzle 11 and the outer nozzle 12 via a notch 12c provided in the step 12a of the outer nozzle 12, and the notch In addition to the illustration, 12 c is provided at equal intervals so as to surround the inner nozzle 11, and the processing gas is jetted around the inner nozzle 11. Needless to say, a cutout portion constituting a part of the gas passage 17 may be formed on the step portion 11 b side of the inner nozzle 11.
Accordingly, the processing gas supplied by a processing gas supply device (not shown) is ejected from the side of the nozzle body 4 to the workpiece 3 through the gas passage 17 and through the gap between the tip portions of the inner nozzle 11 and the outer nozzle 12. Will come to be.
At this time, the outer peripheral surface of the tip portion 11c of the inner nozzle 11 is formed in 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. Therefore, the outlet of the gas passage 16 and the outlet 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 processing site.
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.
[0011]
As understood from the above configuration, since the detection electrode 5 is constituted by 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 sufficiently obtain the capacitance necessary for measuring the distance to the workpiece 3.
At this time, even if the detection electrode 5 is configured only by the outer nozzle 12 as necessary, the outer nozzle 12 is disposed outside the inner nozzle 11, and therefore the detection electrode 5 is configured only by the inner nozzle 11. As compared with the above, the area of the surface facing the workpiece 3 can be increased, and therefore a large capacitance can be easily ensured.
The gas passage 17 is provided between the inner nozzle 11 and the outer nozzle 12, and the outlet of the gas passage 14 and the outlet of the gas passage 17 can be provided close to each other. Since the direction of the processing gas ejected from 17 can be directed to the processing portion of the workpiece by the laser beam, it is possible to effectively prevent the spatter generated during laser processing from adhering to the nozzle.
Further, since the second insulating member 8 is provided between the flange portion 12 b of the outer nozzle 12 and the bent portion 6 a of the guard electrode 6, the gas passage 17 is sufficient on the inner periphery of the guard electrode 6. At the same time as forming an annular space having a capacity, the size of the outer shape of the guard electrode 6 can be suppressed, so that the size of the machining head itself can be made compact.
[0012]
【The invention's effect】
As described above, according to the present invention, it is possible to reduce the possibility that spatter generated during laser processing adheres to the detection electrode as compared with the conventional processing head, and the surface area of the detection electrode facing the workpiece is reduced. Since a large amount can be secured, it is possible to stably measure the distance between the machining head and the workpiece.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a machining head in the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Processing head 3 Workpiece 4 Nozzle main body 5 Detection electrode 6 Support member (guard electrode) 7 1st insulating member 8 2nd insulating member 11 Inner nozzle 12 Outer nozzle 16, 17 Gas passage

Claims (4)

In a processing head of a laser processing machine comprising a detection electrode for detecting capacitance between the processing head and a workpiece, and a guard electrode surrounding the detection electrode,
An inner nozzle that is disposed on the lower surface of the nozzle body of the processing head via a first insulating member and irradiates a laser beam, and surrounds the inner nozzle and is formed on the lower surface of the step portion formed on the outer peripheral surface of the inner nozzle. An outer nozzle that is polymerized and has a gas passage for passing a processing gas between the inner nozzle and the outer nozzle. The outer nozzle surrounds the outer nozzle and is connected to the nozzle body. A support member for supporting the nozzle from below ,
By connecting the support member to the nozzle body, the second insulating member, the outer nozzle, the inner nozzle and the first insulating member are supported from below by the support member and integrally connected to the nozzle body.
A processing head of a laser processing machine, wherein the outer nozzle is used as a detection electrode and the support member is used as a guard electrode. The outer peripheral surface of the inner nozzle and the inner peripheral surface of the outer nozzle each have a tapered shape whose front end side is narrowed, and the gas passage ejects a processing gas toward a processing site by a laser beam. 2. A processing head of the laser processing machine according to 1. The tip end side of the step portion formed on the outer peripheral surface of the inner nozzle is formed to have a small diameter, and the step portion formed on the inner peripheral surface of the outer nozzle is superposed on the lower surface of the step portion of the inner nozzle. The both are electrically connected, and the notch part formed in at least any one step part forms a part of said gas channel, The Claim 1 or Claim 2 characterized by the above-mentioned. Processing head of laser processing machine. The outer nozzle has a flange portion extending outward at an end opposite to the tip side, and the support member has a bent portion extending inward at the tip side. The processing head of a laser beam machine according to any one of claims 1 to 3, wherein a flange portion of the outer nozzle is supported from below via an insulating member.

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