DE102007017363A1 - Device and method for processing components - Google Patents

Abstract

The invention relates to a device and a method for processing components with radiation of a fiber, disc or bar laser. The object of the invention is to achieve improvements in the use of devices with fiber or disk lasers in the machining of components, in which the respective laser light source to be protected from back-reflected radiation and the effectiveness of use is to be increased. A device according to the invention is designed such that radiation emitted by a fiber or disk laser light source is directed onto a beam splitter, which is transparent to radiation directed onto a processing region of a component and reflective to radiation reflected back from the processing region. In this case, the radiation transmitted through the beam splitter is rotatable by a polarization rotator in its polarization direction by a predeterminable angle and directed to the processing area of the component and the reflected radiation from the processing area in its polarization direction with the polarization rotator rotated so that it by means of the beam splitter from the beam path is coupled out and impinges on at least one reflective optical element.

Description

The The invention relates to an apparatus and a method for processing of components with radiation of a fiber, disc or bar laser. The Editing can be done using the various known technologies, such as z. As cutting, welding or for a Modification of materials (eg hardening) as well as the Drilling, ablation, coating and remelting can be used.

since About two years are high-power fiber laser systems and disk lasers available on the market, which is a previously unknown have high beam quality. This makes fiber lasers extraordinary well suited for laser material processing. When using a fiber laser However, it has been found that this is especially reflected back against Radiation is sensitive. This is due to, that the "Auskoppelspiegel" of the laser resonator only one very low reflection, but a very high transmission has. This significantly differentiates the fiber laser from other solid state lasers like the disk laser or Nd: YAG rod laser.

at The treatment of metals usually has a radiation quite high reflection on the workpiece, which is a significant Share (10-90%) reflected back into the laser can be. The resulting high power densities can to destroy the laser or a transmission fiber to lead. For this reason, a feedback inhibit appears absolutely necessary.

That's the way it is JP 60158993 A and JP 61232077 A For general laser sources known to direct back from a component reflected radiation by means of a beam splitter on an absorber. The reflected back radiation is thereby decoupled and made harmless. But it represents a lost share of usable laser power.

at but it is also often desired for editing to use specifically polarized radiation. The one for this used optical elements (polarization rotator) lead but losses that are not used during processing and thereby the efficiency and the efficiency are adversely affected.

It It is therefore an object of the invention to improve the use of Devices with fiber or disk lasers during processing reach of components where the respective laser light source protected from reflected radiation and back the effectiveness in use should be increased.

According to the invention to accomplish this task with a device having the features of the claim 1 and a method according to claim, solved.

there intended for the machining of components or workpieces the radiation of fiber or disk lasers on a processing area be directed. This can be done with a fiber or disk laser light source emitted arbitrary or unpolarized radiation.

at The invention is in the beam path on a processing area directed laser radiation disposed an optical element, the for radiation emitted by the disk or fiber laser transparent in one direction and back for the component reflected radiation is reflective.

The Radiation transmitted through the beam splitter strikes one Polarization rotors and so becomes with their polarization direction rotated by a predetermined angle. This radiation is on the respective processing area of a component court tet. she can be focused in advance by means of a suitable optical element become.

from Machining area of a component reflected back Radiation is also influenced by the polarization rotator and then has a direction of polarization so as to emanate from the beam splitter the beam path or the optical axis and deflected to a is directed reflective element.

With The reflective element makes it possible to see the back to supply reflected radiation to another use.

Cheap is to arrange and align the reflective element so that this radiation travels the same way again, So from the reflective element on the beam splitter through the polarization rotator back to the editing area, together with a "main beam" impinges.

It can be used in the invention, a polarization rotator, with which the polarization direction is rotated by 45 °. It should be arranged in the beam path of the transmitted radiation be.

suitable Polarization rotors are, for example, Faraday rotators or λ / 4 plates.

As already indicated polarized radiation can be used in different forms. For circularly polarized radiation, these can be linearly polarized with a polarization rotator (λ / 4 plate), then again by a beam splitter and another polarization rotator as circularly polarized radiation onto the processing area of a building be partly addressed.

The Radiation reflected back from there will be with the same Polarization rotors are again linearly polarized before passing the beam splitter reached. It's so polarized that it's the one back reflected radiation in the transmission direction blocks, from the Beam path uncouples and toward the reflective element reflected.

Of the Radiation component that reflects from the workpiece for the second time is rotated by 90 ° in the polarization direction, so that he no longer out of the beam path through the beam splitter can be hidden. This by the double absorption significantly weakened portion is reflected back into the laser.

The The invention can be extended by a second beam splitter is used. This can be done in the beam path, starting from the Laser light source may be arranged in front of the first beam splitter. With it is possible for him, the mentioned portion of the processing area deflect back reflected radiation from the beam path. However, between the two beam splitters is still a polarization direction by 45 ° rotating element, z. B. a Faraday rotator, to order. This part of the reflected radiation can be absorbed on an absorbent Element to be addressed. But there is also the possibility this part of the reflected radiation alone or in addition directed to an optical detector.

With an optical detector, the intensity of this radiation component intended and for a control or regulation of the processing be used. For this he can be connected to an electronic control be. For example, this allows the power of the laser light source to adjust.

following the invention is explained in more detail by way of example become.

there demonstrate:

1 a schematic representation of a first example of a device according to the invention;

2 an example of circularly polarized radiation;

3 Another example of a treatment with circularly polarized radiation and

4 an example with two beam splitters.

In 1 An example of a device according to the invention is shown in which radiation emitted by a laser light source (not shown), that is to say a fiber or disk laser, is emitted through a beam splitter 1 directed and the polarization direction by 45 ° with the polarization rotator 2 is turned. In this form, it is focused through the optical element 3 on the processing area of a component 7 on.

Radiation reflected back from the surface of the processing area makes its way to the beam splitter 1 back again, with the polarization direction with the polarization rotator 2 again rotated 45 °. This allows them the beam splitter 1 no longer happen and instead is from the beam splitter 1 here reflected by 90 ° and thus meets the reflective element 4 on. This is aligned here with its flat surface orthogonal to the angle of incidence of the reflected radiation and is thereby back to the beam splitter again 1 and from this back to the machining area of the component 7 can be reused for processing, resulting in an additional reusable share of up to about 95%, which is actually lost in conventional solutions.

In this example, the polarization rotator is 2 a Farraday rotator.

With the example according to 2 should be clarified that circular polarized radiation from a laser light source can be used. It is in front of the beam splitter 1 another polarization rotator 2 ' , arranged here a λ / 4-plate. The resulting linearly polarized radiation is aligned with its polarization direction so that the beam splitter 1 is permeable to them.

Following the beam splitter 1 is another polarization rotator 2 arranged, with which the polarization direction is again rotated by 45 °. For from the machining area of the component 7 back reflected radiation meet the polarization rotator 2 and the beam splitter 1 again the functions, as in the example after 1 already explained and are therefore arranged and designed accordingly.

At the in 3 shown example can be emitted by a laser light source and circularly polarized radiation as a circularly polarized radiation for processing on a component 7 be directed. These are on both sides of the beam splitter 1 The rotator 2 ' , here formed as λ / 4 plates arranged.

With the λ / 4 plate shown here above 2 ' the circularly polarized radiation is linearly polarized, so that the radiation has a polarization direction for the beam splitter 1 is transparent. With the below the beam splitter 1 arranged λ / 4 plate 2 ' becomes the transmitted radiation again circularly polarized and thus directed to the processing area.

Radiation reflected back therefrom becomes with the λ / 4 plate arranged below 2 ' again linearly polarized in such a way that they are from the beam splitter 1 towards the reflective element 4 can be reflected.

It There is also the possibility of this radiation the same way back to the editing area to judge.

Is the reflective element 4 aligned in a form not shown here and possibly also formed as a focusing mirror, the reflected back radiation from the side can be directed as a second additional beam on the processing area. In this case, the reflective element 4 also be pivotable about at least one axis, so that it can represent a scanner mirror.

This in 4 example shown is with two beam splitters 1 and 1' educated. The radiation reflected for the second time by the workpiece is rotated 90 ° relative to the radiation reflected for the first time so that it is the beam splitter 1 can happen. For this reason, a second beam splitter ( 2 ), which reflects this radiation from the beam path. However, it is necessary to arrange a phase rotator (45 °) between both beam splitters and the beam splitter 1 also to turn 45 °.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - JP 60158993 A [0004]
• - JP 61232077A [0004]

Claims (14)

Device for processing components, in which radiation emitted by a fiber or disk laser light source is irradiated onto a beam splitter ( 1 ) directed to a working area of a component ( 7 ) radiation is transparent and reflective for reflected back from the processing area radiation is through the beam splitter ( 1 ) transmitted radiation through a polarization rotator ( 2 ) in its polarization direction rotatable by a predeterminable angular amount and so on the processing area of the component ( 7 ) is directed; and the radiation reflected from the processing area in its polarization direction with the polarization rotator ( 2 ) is rotated so that it by means of the beam splitter ( 1 ) is coupled out of the beam path and at least one reflective optical element ( 4 ). Device according to Claim 1, characterized in that the reflective optical element ( 4 ) is arranged and aligned so that the radiation from the beam splitter ( 1 ) is reflected back to the processing area. Device according to claim 1 or 2, characterized in that a polarization rotator ( 2 ), which rotates the polarization direction by 45 °, is arranged in the beam path of the transmitted radiation. Device according to one of the preceding claims, characterized in that with a polarization rotator ( 2 ' ) or a λ / 4 phase shift circularly polarized radiation of the laser light source linearly polarized by the beam splitter ( 1 ) and with a second polarization rotator ( 2 ) The polarization direction of the radiation is rotated by 45 ° and directed to the processing area. Device according to one of the preceding claims, characterized in that the polarization rotator (s) ( 2 . 2 ' ) one or more Faraday rotator (s) is / are. Device according to one of the preceding claims, characterized in that a second beam splitter ( 1' ) is arranged in the beam path of the radiation emitted by the laser light source with which the radiation reflected back for the second time from the processing area reflects out of the beam path and onto an absorbing element ( 8th ) and / or an optical detector is directed. Device according to claim 6, characterized in that that the optical detector to a control of the laser light source connected. Apparatus according to claim 8 or 9, characterized in that between the two beam splitters ( 1 . 1' ) another polarization rotator ( 3 ) is arranged. Method for processing components with a device according to one of claims 1 to 8, wherein the radiation of a fiber or sliced laser on a beam splitter ( 1 ) is directed through the beam splitter ( 1 ) and transmits the transmitted radiation with a polarization rotator ( 2 ) and on a processing area of a component ( 7 ); In addition, reflected radiation from the processing area back with the polarization rotator ( 2 ) is rotated in its polarization direction so that it is separated from the beam splitter ( 1 ) is coupled out of the beam path of the transmitted radiation and onto a reflective element ( 4 ) is reflected. Method according to claim 9, characterized in that radiation reflected back from the processing area from the beam splitter ( 1 ) to a radiation reflecting element ( 4 ), that of the reflective element ( 4 ) the radiation on the beam splitter ( 1 ) and from there back to the editing area. A method according to claim 9 or 10, characterized in that the radiation by means of a polarization rotator ( 2 ' ) is directed as circularly polarized radiation on the processing area. Method according to one of claims 9 to 11, characterized in that emitted circularly polarized radiation with a polarization rotator ( 2 ' ) linearly polarized and by a beam splitter ( 1 ) and another polarization rotator ( 2 ' ) is directed as circularly polarized radiation on the processing area. Method according to one of claims 9 to 12, characterized in that a second beam splitter ( 1' ) is arranged in the beam path of the radiation emitted by the laser light source with which the radiation reflected back for the second time from the processing area reflects out of the beam path and onto an absorbing element ( 8th ) and / or an optical detector is directed. Method according to claim 13, characterized in that that by means of an optical detector instead of an absorber the laser light source is controlled and / or the machining process (Welding, cutting, drilling, etc.) is regulated.