JPS61262481A - Laser beam machine - Google Patents

Abstract

PURPOSE:To provide a laser beam machine which can maintain the mirror and lens face in a beam chamber in a clean state enclosing an optical path for a laser bean from a laser oscillator to a condenser lens of a processing head by connecting a vacuum pump to said beam chamber and maintaining the inside of said chamber under a negative pressure. CONSTITUTION:The laser beam oscillated from a laser oscillating chamber 1 is irradiated through the condenser lens 3 on a work through the beam chamber 5 in which the negative pressure is maintained by the vacuum pump 6. The work is thereby processed. The dust, etc. present in the chamber 5 are thus decreased by the low pressure in the chamber 5 and the mirror and lens face of the chamber 5 can be maintained in the clean state. The thermal expansion in the narrow space of the chamber 5 is suppressed and further the distortion of the transverse mode of the laser beam is suppressed. The dew point temp. in the chamber 5 is shifted to a low temp. side and the deterioration of the mirror, etc. by dew condensation is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a laser processing apparatus for processing a workpiece with a laser beam.

(Prior art) In a table-moving laser processing device, a laser beam output from a laser oscillator is transmitted along a cylindrical pipe, incident on a light transmission folding mirror, and then a screw that can be expanded and contracted in the vertical direction. The workpiece is processed by irradiating the workpiece on the processing table from a condensing lens through the cover.

[Problem that the invention seeks to solve]

In such a conventional configuration, although the optical transmission space is protected by a cylindrical pipe, a screw cover, etc., it is always open to the atmosphere. If laser processing is performed in such a state, the following problems arise.

In other words, particles in the air get mixed into the laser beam transmission space, making it easy for dust to adhere to the surface of the optical transmission mirror, and once the laser beam is irradiated to the adhered area, the absorption rate increases. This results in a local temperature rise, which shortens the life of the optical transmission folding mirror.

Furthermore, if the optical transmission space as described above is surrounded by a cylindrical pipe, a screw cover, etc. in a spatially narrow i region, a non-uniform space will be formed due to thermal expansion during long-term laser processing. In general, when light propagates through free space, it is said that although the beam size etc. may change, transverse modes etc. are not affected.However, as mentioned above, when light propagates through non-uniform space, transverse modes It is said that such distortions are likely to occur. Therefore, if a narrow area is covered with a cylindrical pipe or the like, the transverse mode of the laser beam will change in the transmission space during long-term laser processing, which will affect the laser processing.

[Means for solving problems]

In this invention, a beam chamber 5 is provided by surrounding the optical path of the laser beam from a laser oscillator 1 to a condensing lens 3 of a processing head 2 with a partition wall 4, and a vacuum pump 6 is connected to this beam chamber 5 to provide a negative This is a configuration of a laser processing apparatus characterized in that the laser processing apparatus is capable of producing pressure.

[Action and effect of the invention]

A laser beam emitted from a laser oscillator 1 passes through a beam chamber 5 maintained at negative pressure by connecting a vacuum pump 6, and is irradiated onto a workpiece through a condensing lens 3 to process the workpiece. It is something. As a result, the presence of dust and the like can be reduced due to the low pressure inside the beam chamber 5, and the mirrors and lens surfaces of the beam chamber 5 can be kept in a clean state. Furthermore, thermal expansion of the narrow space of the beam chamber 5 can be suppressed, and distortion of the transverse mode of the laser beam can be suppressed. Furthermore, the dew point temperature within the beam to 5 can be shifted to a lower temperature side, thereby preventing deterioration of mirrors and the like due to dew condensation.

〔Example〕

In the illustrated example, the machine body 7 is provided with a processing table 9 on which a workpiece 8 is placed, a work clamp device 15, etc. at the lower part, and an upper frame 10 and a processing head 2 at the tip thereof at the upper part. The beam chamber 5 connects the optical path of the laser beam 11 with a pipe-shaped partition wall 4.
The upper frame 10 is surrounded by a horizontal portion 12 that extends horizontally, and the processing head 2 is formed in a mountain shape by a vertical portion 13 that extends vertically. A condensing lens 3 is provided at the lower end of the portion 13. Moreover, the end of the horizontal portion 12 on the side of the laser oscillator 1 is
A laser hole, glass, lens, etc., are provided to allow the laser beam 11 to enter, so that the inside of the beam 5 is made as airtight as possible.

The laser oscillator 1 is connected to the rear end of the upper frame 10 of the machine stand 2,
The interior is constructed to be as airtight as possible.

The laser beam 11 irradiating part of this laser oscillator 1 is connected to the rear end of the horizontal portion 12 of the beam chamber 5, so that it can enter the beam chamber 5.

The laser oscillator 1 and the beam chamber 5 are connected by a vacuum pump 6 and pipes 16, 17, etc. to evacuate them together, but the laser oscillator 1 is normally maintained in a vacuum state as a completely closed container. However, the laser chamber 5 does not necessarily have to be a completely closed container, as long as it can be drawn to a low pressure below atmospheric pressure.

A laser beam 11 emitted from a laser oscillator 1 passes through a horizontal portion 12 of a beam chamber 5, is refracted by a mirror 14, passes through a vertical portion 13, passes through a condensing lens 3, and is directed to the workpiece on a processing table 9 below. It processes object 8.

By driving the vacuum pump 6, the inside of the laser oscillator 1 and the beam chamber 5 are brought to a vacuum or low pressure.Next, the relationship between the vacuum pressure and the air density will be shown.

That is, temperature: T ("C), pressure crab H (IIHl))
The density of dry air 2M is given by the following equation:

M-(0,001293/ 10.00367T)
x (H/ 760) g/co+3 Now, temperature T-
200”, then M −0,0OOO01
Since it is expressed as 5H, it is clear that the dry air density M is proportional to the pressure H, and the effect of reducing air density M and reducing dust in the air by vacuuming is sufficiently large. .

Furthermore, by maintaining the beam chamber 5 at a low pressure, it also helps to prevent dew condensation on the mirror 14 for light transmission. The saturation line, which indicates the saturation limit of the amount of water vapor that can exist in the atmosphere, indicates that at the same temperature, the lower the atmospheric pressure, the higher the absolute saturated humidity, so if the atmospheric pressure is low, condensation is less likely to occur.

[Brief explanation of drawings]

The figures show one embodiment of the present invention, with Figure 1 being a side view and Figure 2! ! I is a route diagram partially cut away. (1) is the laser oscillator, (2) is the processing head (3)
is the condenser lens (4) is the partition wall (5) is the beam chamber
(6) indicates a vacuum pump.

Claims (1)

[Claims] The optical path of the laser beam from the laser oscillator 1 to the condensing lens 3 of the processing head 2 is surrounded by a partition wall 4 to form a beam chamber 5.
A laser processing apparatus characterized in that a vacuum pump 6 is connected to the beam chamber 5 to create a negative pressure.