JPH11277286A - Laser processing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit laser light output from a laser oscillator to a condenser lens without distortion, and to stabilize the laser light for a long time by avoiding a local temperature rise in an optical path duct by a high cleaning effect. Obtain a laser processing device that enables processing. A laser beam guided from a laser oscillator is provided.
In a laser processing apparatus in which an optical path duct 3 is provided in an optical path leading to a workpiece 8, a temperature measuring device 12 for measuring temperatures at a plurality of locations along a longitudinal direction in the optical path duct 3; Temperature controller 1 for maintaining a uniform and constant temperature distribution of gas in optical path duct 3 based on output
3 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for stabilizing beam propagation in, for example, a laser processing apparatus.

[0002]

2. Description of the Related Art A conventional laser processing apparatus is constructed as shown in FIG.
Is guided to a total reflection mirror 4 for laser beam bending through an optical path duct 3 having a protective cover function for protection and safety. The laser light emitted from the oscillator 1 by the total reflection mirror 4 is bent by 90 ° and guided to the condenser lens 5. The laser beam 2 is condensed by the condensing lens 5, and is radiated through a processing nozzle 6 onto a workpiece 8 placed on a table 7. In this type of laser processing apparatus, an air inlet 9 is provided in the middle of the optical path to keep the air in the optical path clean, and dry air of a constant pressure is supplied into the optical path by the compressor 10,
The air that has entered the optical path is configured to be exhausted from the tip of the optical path, for example, from a small hole 11 near the processing nozzle 6.
With these structures, the air pressure in the optical path is maintained at a pressure slightly higher than the outside air pressure to prevent dust from entering the optical path from the outside and contaminating optical components such as the total reflection mirror 4. ing.

[0003]

However, in the above-described optical path propagation device of a conventional laser processing apparatus, when a laser beam is propagated over a long distance as in an optical scanning type laser processing apparatus, for example, Since a sufficient cleaning effect cannot be obtained, the dust remaining in the air in the optical path is heated by the laser beam, and a temperature difference occurs in the optical path. Due to such a local temperature difference, a bias occurs in the air density in the optical path, and the laser light undergoes a refraction phenomenon due to the thermal lens effect of the gas, so that the optical axis of the laser light changes or the laser light in the optical path changes. The diameter changes. As a result, since the diameter of the laser beam incident on the condenser lens necessarily changes, there is a problem that the diameter of the condensed spot changes and the focal position changes, so that normal cutting cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and transmits a laser beam output from a laser oscillator to a condenser lens without distortion, and a local temperature in an optical path due to a high cleaning effect. This is a laser processing device that enables long-term stable processing by avoiding rising.

[0005]

According to the present invention, there is provided a laser processing apparatus comprising: a temperature measuring means for measuring temperatures at a plurality of locations along a longitudinal direction in an optical path duct; and an optical path based on an output of the temperature measuring means. Temperature control means for maintaining a uniform and constant temperature distribution of the gas in the duct.

A branch duct having a branch outflow path and a branch inflow path communicating with the optical path duct, and air that is provided in the branch duct and flows out of the optical path duct through the branch outflow path through the branch inflow path through the optical path duct. A fan and a heat exchanger for circulating the air in the optical path duct by flowing into the duct are provided, and the fan operates based on an output from the temperature control means.

Further, a plurality of branch inflow paths are provided.

Further, a flow control valve is provided in the branch duct.

Furthermore, a filter for removing dust is provided near the fan in the branch duct.

[0010] Further, the plurality of branch inflow paths are provided corresponding to positions where the temperature is measured by the temperature measurement means in the optical path duct.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 A laser processing apparatus according to a first embodiment of the present invention will be described with reference to FIG. In FIG. 1, reference numerals 1 to 8 are the same as or corresponding to those in the drawings of the conventional example, and thus description thereof is omitted. 12 is a temperature measuring device, and 13 is a temperature control device. A laser beam 2 oscillated from a laser oscillator 1 is guided to a total reflection mirror 4 for bending a laser beam through a protection and safety optical path duct 3 having a pipe shape. After being bent 90 ° by the total reflection mirror 4, the laser beam 2 is condensed by the condensing lens 5, and irradiates the workpiece 8 installed on the table 7 through the processing nozzle 6. When the above apparatus performs laser processing such as welding and drilling by transmitting laser light over a long distance, the processing state changes depending on the quality and shape of the laser light. For example, in laser welding, the welding depth and the welding width change. Further, in laser cutting, there are effects such as the size of the cutting width and the presence / absence of adhesion of a melt. This is because the density of air is deviated due to a local temperature difference generated in the optical path duct 3, and the laser beam 2 causes a refraction phenomenon due to the thermal lens effect of gas. As a means for measuring such a local temperature distribution generated in the optical path duct 3, a plurality of temperature measuring devices 12 are installed in the optical path duct 3 as shown in FIG. 1, and the temperature in the optical path at each location can be measured. It is like. In addition, all the temperature measuring devices 12 installed in the optical path duct 3 can be centrally controlled by a temperature control device 13.
The temperature distribution inside can be grasped.

Further, a cooler is provided integrally with the temperature measuring device 12, and the air in the optical path duct 3 is cooled by the plurality of coolers, so that the temperature distribution of the gas in the optical path is made uniform and uniform. It may be maintained at a constant value.

Embodiment 2 FIG. Next, a laser processing apparatus according to a second embodiment of the present invention will be described with reference to FIG. In FIG. 2, reference numerals 1 to 8, 12 and 13 are:
The description is omitted because it is the same as or equivalent to that of the drawings of the first embodiment. 14 is a branch outflow channel, 15
Is a branch inflow path, 16 is a heat exchanger, and 17 is a fan.
The branch outflow path 14 and the branch inflow path 15 constitute a branch duct. Further, the plurality of branch inflow paths 15 are provided corresponding to the positions where the temperature measuring devices 12 in the optical path duct 3 are installed. From the measurement results of the plurality of temperature measuring devices 12 installed in the optical path duct 3, the temperature control device 13
Calculates the average value M. When the deviation from the average value M at each measurement point exceeds a certain standard, the temperature controller 13
Issues a command to operate the heat exchanger 16 and the fan 17. When the fan 17 rotates, the branch outflow path 1 connected to both ends of the optical path duct 3 (the oscillator 1 side and the total reflection mirror 4 side)
4, the air in the light path duct is sucked up and cooled by the heat exchanger 16, and then returns to the light path duct 3 through the branch inflow path 15 again. In this way, the air in the optical path duct 3 continues to circulate through the heat exchanger 16 until the deviation between the temperature measurement result at each measurement point and the average value M converges within a certain reference value.

Embodiment 3 Next, a laser processing apparatus according to a third embodiment of the present invention will be described with reference to FIG. In FIG. 3, reference numerals 1 to 8 and 12 to 17
Are the same as or equivalent to those in the drawings of the second embodiment, and a description thereof will be omitted. 18 is a flow control valve. In the second embodiment described above, air at a certain temperature flows into the optical path duct 3 from the plurality of branch inflow paths 15 at the same time by the same amount. In each of the embodiments, a flow control valve 18 is installed in each of the plurality of branch outflow paths 15 connected to the optical path duct 3, and the temperature control device 13 that centrally manages the temperature distribution in the optical path duct 3 is provided by each of the flow control valves 18. Then, a flow rate command for obtaining the most appropriate and efficient cooling effect is issued. For example, the flow control valve 1 of the branch inflow path 15 that allows air to flow into a place where the temperature is higher than the average value M calculated by the temperature control device 13.
8, a command to open the valve greatly is issued, and a command to close the valve is issued to the flow control valve 18 installed at a location with a low temperature. If the deviation between the temperature measurement result and the average value M at each measurement point converges within a certain reference value, all the flow control valves 18 are closed, and the operations of the heat exchanger 16 and the fan 17 are stopped at the same time.

Embodiment 4 Next, a laser processing apparatus according to a fourth embodiment of the present invention will be described with reference to FIG. In FIG. 4, reference numerals 1 to 8 and 12 to 17
Are the same as or equivalent to those in the drawings of the third embodiment, and therefore description thereof is omitted. 19 is a branch intermediate road. In the fourth embodiment, the heat exchanger 16 and the fan 17 are provided in each of the plurality of branched intermediate paths 19, and the heat exchange efficiency of the air in the optical path duct 3 is further improved. . The measurement result of the temperature measuring device 12 arranged near the connection between the plurality of branch intermediate paths 19 from the branch outflow path 14 and the optical path duct 3 is transmitted to the temperature control device 13.
Will be fed back. The temperature controller 13 calculates an average value M from the measurement results, and based on the deviation at each measurement point,
A command for cooling or heating is given to each heat exchanger 16. At this time, each heat exchanger 16 and the fan 17
Operates, the air in the optical path duct 3 is divided into the branch outflow path 1
After being sucked up from the heat exchanger 4, it is cooled or heated through each heat exchanger 16 and flows again into the optical path duct 3. Further, if the temperature control device 13 simultaneously controls the number of rotations of the fan, the temperature distribution of the air in the optical path duct 3 becomes uniform in a shorter time. Finally, if the deviation between the temperature measurement result at each measurement point and the average value M converges within a certain reference value, all the heat exchangers 16 and the fans 17 are stopped.

Embodiment 5 Next, a laser processing apparatus according to a fifth embodiment of the present invention will be described with reference to FIG. In FIG. 5, reference numerals 1 to 8, 12 to 17,
19 is the same as or equivalent to that in the drawings of the fourth embodiment, and a description thereof will be omitted. 20 is a filter. In the fifth embodiment, since the filter 20 is mounted immediately after each heat exchanger 16, the inside of the optical path duct 3 containing dust sucked out from the vicinity of the laser oscillator 1 and the total reflection mirror 4 by the rotation of the fan 17. Is circulated through the heat exchanger 16 again into the optical path duct 3 and is filtered by the filter 20. by this,
Clean air always flows into the optical path duct 3.

[0017]

As described above, according to the present invention,
Temperature measuring means for measuring the temperature at a plurality of locations along the longitudinal direction in the light path duct, and temperature control means for maintaining a uniform and constant temperature distribution of the gas in the light path duct based on the output of the temperature measuring means With the above arrangement, it is possible to suppress the local temperature rise in the optical path due to the heat of the laser light, and realize stable processing without causing the laser light to propagate in a distorted state or refraction phenomenon It has the effect of being able to.

A branch duct having a branch outflow path and a branch inflow path communicating with the optical path duct; and air that is provided in the branch duct and flows out of the optical path duct through the branch outflow path through the branch inflow path. By providing a fan and a heat exchanger that circulate the air in the optical path duct by flowing into the duct, local temperature rise in the optical path can be suppressed with a simple configuration, and the laser beam is refracted. Therefore, there is an effect that stable processing can be realized without causing or propagating in a distorted state.

Further, since a plurality of branch inflow paths are provided, the cooled air can be easily spread over a wide range in the optical path, and the temperature distribution in the optical path can be maintained uniformly.

Further, by providing the flow control valve in the branch duct, there is an effect that the air flowing into the optical path duct can be easily controlled only by opening and closing the valve.

Further, by providing a filter for removing dust near the fan in the branch duct, dust entering the optical path is removed, and the optical path is constantly cleaned, whereby the optical path caused by dust is removed. This produces an effect that the heat generation phenomenon in the inside can be suppressed.

Also, since a plurality of branch inflow paths are provided respectively corresponding to the positions where the temperature is measured by the temperature measuring means in the optical path duct, they directly correspond to the places in the optical path duct where the temperature changes. Thus, there is an effect that efficient temperature control becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a laser processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic view showing a laser processing apparatus according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram showing a laser processing apparatus according to a third embodiment of the present invention.

FIG. 4 is a schematic view showing a laser processing apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a schematic view showing a laser processing apparatus according to a fifth embodiment of the present invention.

FIG. 6 is a schematic view showing a conventional laser processing apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 laser oscillator 2 laser light 3 optical path duct 12 temperature measuring device 13 temperature control device 14 branch outflow path 15 branch inflow path 16 heat exchanger 17 fan 18 flow control valve 19 branch intermediate path 20 filter

Claims (6)

[Claims] In a laser processing apparatus having an optical path duct provided in an optical path of a laser beam guided from a laser oscillator to a workpiece, a temperature for measuring a temperature at a plurality of positions along a longitudinal direction in the optical path duct is measured. A laser processing apparatus comprising: a measuring unit; and a temperature control unit that maintains a uniform and constant temperature distribution of gas in the optical path duct based on an output of the temperature measuring unit. 2. A branch duct having a branch outflow path and a branch inflow path communicating with an optical path duct, and air that is provided in the branch duct and flows out of the optical path duct through the branch outflow path through the branch inflow path through the light path. 2. The apparatus according to claim 1, further comprising a fan and a heat exchanger for circulating the air in the light path duct by flowing into the duct, wherein the fan operates based on an output from the temperature control means. The laser processing apparatus according to the above. 3. The laser processing apparatus according to claim 2, wherein a plurality of branch inflow paths are provided. 4. The laser processing apparatus according to claim 2, wherein a flow control valve is provided in the branch duct. 5. The laser processing apparatus according to claim 2, wherein a filter for removing dust is provided near the fan in the branch duct. 6. The laser processing apparatus according to claim 3, wherein the plurality of branch inflow paths are respectively provided corresponding to positions where the temperature is measured by the temperature measuring means in the optical path duct.