JP3029864B2 - Cooling method of external optical parts of laser beam machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cooling device for an external optical component of a laser beam machine.

(Prior art) The reflection mirror and condenser lens outside the oscillator of a laser beam machine are made of a material that reflects or transmits laser light with high efficiency. Forced cooling with cooling water was required.

However, when water is used for cooling, dew condensation may occur on the surfaces of the reflection mirror and the condenser lens due to the relationship between the outside air temperature and humidity, and water droplets may adhere to the surfaces of the reflection mirror and the condenser lens. In the case of a carbon dioxide laser, these water droplets absorb light, so that the reflection mirror, the condenser lens, and the like are heated and may be damaged.

In addition, in the case of cooling with outside air, not only the cooling capacity is insufficient, but also in the case of cooling the condenser lens, the surface is directly blown with air, so that dust and dirt adhere to the surface.
The dust similarly absorbed the carbon dioxide laser light, and the condenser lens was heated and sometimes damaged.

(Problems to be Solved by the Invention) Generally, a reflection mirror, a condensing lens, and the like used for reflection and transmission of a laser beam have low resistance to water, and easily cause peeling of a coating. However, recently, high output of the oscillator is required, so that it is inevitable to use water cooling. If the temperature of the cooling water is close to the temperature of the outside air, the possibility of dew condensation is reduced.However, there are many places where the oscillator is also water-cooled, and the rise in the temperature of the cooling water directly lowers the oscillation efficiency, that is, lowers the laser output. Becomes

The present invention has been made in view of such a point, and prevents contamination and dew condensation of a laser reflection mirror, a condenser lens, and the like, stabilizes the life of these external optical components, and achieves high output. It is an object of the present invention to provide an effective cooling device for an external optical component of a laser.

[Constitution of the Invention] (Means for Solving the Problems) In view of the above problems, the present invention cools at least one of a reflection mirror for changing the optical path of a laser beam and a condenser lens by circulating water or the like. In laser processing machines,
A valve for regulating the circulation of water is provided in the cooling water channel, the valve is opened in synchronization with the opening of the shutter of the laser oscillator, and the valve is closed after a fixed time from the closing of the shutter.

(Operation) Since the laser processing machine is operated and the shutter of the oscillator is opened, the laser beam irradiates the workpiece through the reflection mirror, the condenser lens, and the like because of the configuration described above. In this case, the reflection mirror and the condenser lens are heated by the laser beam as described above, but at the same time, the valve provided in the cooling water passage is opened and cooled by the cooling water. The temperature rise subsides to some extent.
When the laser processing is completed, the valve is closed after a certain period of time after the shutter is closed, so that the reflection mirror, the condenser lens, and the like are not unnecessarily cooled. Therefore, moisture in the outside air does not condense on the surfaces of these components.

(Example) Next, an example of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view in which the method of the present invention is applied to a carbon dioxide laser beam machine. As shown, the carbon dioxide laser beam machine 1 is controlled by the NC device 3, and the laser beam L emitted from the carbon dioxide laser oscillator 5 is reflected by the reflection mirror 7.
Changes the optical path by 90 degrees, is condensed by the condensing lens 9, connects the convergence point on the workpiece W, and performs laser processing such as drilling, cutting, and welding.

On the other hand, the cooling water cooled to a low temperature by the heat exchanger 11 cools the laser gas and the like of the carbon dioxide gas laser oscillator 5, and also cools the reflection mirror 7, the condensing lens 9, etc. via the electromagnetic valve 13, and the heat exchanger 11 It is cooled back and used for circulation.
When the shutter of the carbon dioxide laser oscillator 5 opens, the solenoid valve 13 opens and passes cooling water according to a command from the NC device 3, and closes after a certain period of time when the shutter closes to stop the cooling water. Timer 15 provided between solenoid valve 13 and NC device 3
Is an off-delay timer that closes the solenoid valve 13 after a certain period of time has elapsed since the shutter was closed.

With such a configuration, when the laser processing is started, the reflection mirror 7 and the condenser lens 9 are cooled by the cooling water. However, when the laser processing is completed, after a certain period of time, their temperatures are adjusted to an appropriate temperature. When lowered, the cooling water is turned off. Therefore, since the reflection mirror 7 and the condenser lens 9 are not cooled to a temperature lower than necessary, dew condensation does not occur.

Also, when laser processing is performed intermittently,
When the non-irradiation time of the laser beam to the work is shorter than the predetermined time, continuous cooling is effectively performed without stopping the supply of the cooling water to the condenser lens 9 and the like.

As described above, an object of the present invention is to cool an external optical component so that moisture in the outside air does not condense on its surface when cooling the external optical component. Therefore,
As in the present invention, the effect can be further enhanced by restricting the flow of the cooling water by the solenoid valve and controlling the amount of the cooling water by the laser output. Further, cooling water having a relatively high temperature which is output after cooling the laser oscillator may be used as cooling water for the external optical components. Further, the cooling water before entering the external optical component may be heated by a heater or the like so as to reduce the difference from the outside air temperature.

[Effects of the Invention] As can be understood from the above description, since the present invention has the configuration described in the claims, contamination and dew condensation of the reflection mirror and the condenser lens of the laser can be prevented. In addition to stabilizing the life of the external optical component, the external optical component of the high-power laser can be effectively cooled.

[Brief description of the drawings]

FIG. 1 is an explanatory view in which the present invention is applied to a carbon dioxide laser beam machine. 1 ... carbon dioxide laser processing machine, 13 ... solenoid valve, 15 ... timer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B23K 26/06 H01S 3/04

Claims (1)

(57) [Claims] 1. A laser processing machine for cooling at least one of a reflection mirror for changing the optical path of a laser beam and a condenser lens by circulating water or the like. A valve for opening the valve in synchronization with the opening of the shutter, and closing the valve after a fixed time from the closing of the shutter.