JPS603992A - Protecting method of reflecting mirror and condenser lens for laser light - Google Patents

Abstract

PURPOSE:To protect a reflecting mirror and a condenser lens for laser light against suspended dust with a precision laser working machine by maintaining the inside of a laser passage in a pressurized state with the clean air. CONSTITUTION:A laser nozzle 1 of an X-Y nozzle moving type laser working machine or the like moves freely on a working table 2 and processes a work 3. The laser light emitted from an oscillator 4 is passed through the inside of a laser light passage 5 by mirrors M1-M4 until the light arrives at the condenser lens of the nozzle 1. An introducing port 6 for pressurized clean air is provided to the base part of such passage 5 and the pressurized clean air is fed therein. Then the intrusion of suspended dust into the passage is prevented during movement of the nozzle 1 or adjustment of the mirrors, by which the life of the mirrors, etc. is extended. The intrusion of the gas generated during working into the passage 5 is further prevented and the accuracy and efficiency of working are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for protecting a laser beam reflecting mirror and a condensing lens in a laser processing machine characterized by non-contact precision processing.

A laser beam with a single wavelength and high energy density can evaporate, melt, or change the structure of various materials, so it is used in so-called non-contact processing for cutting, engraving, welding, hardening, etc. steel plates and boards. The mirrors and lenses used in processing machines that use this laser beam are made of special materials and are coated with silicone on their surfaces, making them unusable after about a month, even though they are expensive. When we investigated the cause of this, we found that there was floating dust, especially iron powder chips adhering to the mirror surface when cutting the workpiece, and that this was sintered by the subsequent laser beam irradiation, contaminating the silicon surface and reducing the reflectance. It has been found that this phenomenon occurs especially with mirrors facing sideways or upwards. Measures have been taken to prevent floating dust from entering the laser optical path, such as installing a cover over the entire optical path, but when adjusting the mirror, the bellows-shaped cover expands and contracts as the laser nozzle moves, allowing dust to enter through even a small gap. That's what I do.

In addition to the reduction in mirror reflectance due to floating dust, other factors have been identified that reduce cutting ability. This is because gas is generated when cutting plastics such as acrylic or ABS resin, and when this enters the optical axis, the refractive index of the laser beam changes and the output decreases.

The above phenomenon occurs when the processing table is fixed and the laser nozzle is
This is particularly noticeable in nozzle moving type laser processing machines that move in the Y direction, and this is because the slider expands and contracts like a bellows, and as it expands, it sucks in outside air.

The present invention was developed as a result of intensive research aimed at solving the above-mentioned problems with laser processing machines. i.e. 1
All of the above problems were solved by keeping the laser light path from the transmitter body to the laser nozzle under pressure with clean air.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a plan view of an X-Y nozzle moving type laser processing machine implementing the method of the present invention, and FIG. 2 is a front view of the same. The method of the present invention can be implemented not only in this XY nozzle moving type laser processing machine but also in a workpiece moving type laser processing machine. In the figure, a laser nozzle (1) moves freely in the X-Y directions on a workbench (2) to process a workpiece (3). The laser light emitted from the oscillator (4) passes through the laser light path (5) and reaches the condenser lens of the laser nozzle (1) via mirrors (M1 to M4).

In this example, the mirror (Ml) (M4) faces downward, and the mirror (M
3) is facing sideways, and the mirror (Ml) is facing upward, especially with the mirror surface facing upward.The damage to the mirror surface of the mirror (Ml) is significant.
is located directly below the mirror (Ml) in FIG. The sideways mirror (M3) is then damaged. Furthermore, since the condensing lens (9) above the nozzle (1) is arranged horizontally, it will suffer early damage like the mirror (Ml). The laser light path (5) has a telescopic structure so that it can move in any of the X and Y directions.

It has a sealed structure with the protective pipes (7) and bellows (8) directed to two locations.6 However, when the bellows (8) extend, the inside of the optical path (5) becomes depressurized and outside air is sucked in. Contamination within the laser beam path (5) occurs due to floating dust and gas. Therefore, as a result of various studies, the inventor of the present invention established a pressurized clean air inlet (6) at the base of the laser light path (5) as shown in the figure, and by supplying pressurized clean air from this. It was discovered that there was no contamination within the laser light path (5). It is sufficient that this pressurization is slightly pressurized. This prevents contamination of the laser beam reflection mirror and condensing lens.

By implementing the method for protecting a laser beam reflecting mirror and a condensing lens of the present invention, the intrusion of floating dust during movement of the laser nozzle or adjustment of the mirror was prevented, and the lifespan of the mirror etc. was therefore extended.

In addition, it is possible to prevent gas generated during processing from entering the laser light path (5), resulting in improvements in processing precision and efficiency.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an X-Y nozzle moving type laser processing machine implementing the method of the present invention, and FIG. 2 is a front view of the same. (1) Laser nozzle (2) Workbench (3) Workpiece (4) Oscillator (5) Laser light path (6) Pressurized clean air inlet (7)
) Protective pipe (8) More than bellows Applicant Oimatsu Co., Ltd. Industrial agent Patent attorney - Hirozo Mori

Claims (1)

[Claims] 1. A method for protecting a laser beam reflecting mirror and a condensing lens, which comprises maintaining the laser beam path from the transmitter body to the laser nozzle in a pressurized state with clean air.