WO2022111867A1

WO2022111867A1 - Laser machining device having multiple applications

Info

Publication number: WO2022111867A1
Application number: PCT/EP2021/068745
Authority: WO
Inventors: Bernhard Lang; Christian Lang
Original assignee: LANG LASER - System GmbH
Priority date: 2020-11-26
Filing date: 2021-07-07
Publication date: 2022-06-02
Also published as: DE102020131405A1

Abstract

The invention relates to a device for machining materials by means of electromagnetic radiation, wherein the materials to be machined are preferably flexible materials, said device comprising a radiation source for producing an electromagnetic beam, in particular a laser beam, a mirror-deflection system that deflects the electromagnetic beam, and a focusing lens. The device is characterised in that a diffractive optical element (DOE) is located in the beam path of the electromagnetic beam between the mirror-deflection system and the focusing lens, said diffractive optical element being intended to divide the beam path into two or more beam paths, in order to produce a pattern of machining points on the material to be machined and/or in order to position the machining point or machining points on the material.

Description

DEVICE FOR LASER MATERIAL PROCESSING WITH MULTIPLE APPLICATIONS

The invention relates to a device for processing materials by means of electromagnetic radiation, a mirror deflection system and a focusing lens according to claim 1, and a beam multiplication device according to claim 12.

State of the art:

Laser beam sources, among other things, are used to generate perforations, lines or free-form contours in different materials. These are used in particular in conjunction with a mirror deflection system (scanner) and a focusing lens (F-Theta lens) by means of which the laser beam is directed onto the workpiece/product to be processed.

Object and advantages of the invention:

The object of the invention is to provide a more efficient processing method for producing perforations, lines, free-form contours or similar processing operations in different materials using laser beam sources.

The object is achieved by the features of claims 1 and 12. Advantageous and expedient developments are specified in the dependent claims. Accordingly, the invention relates to a device for processing materials by means of electromagnetic radiation, the materials to be processed preferably being flexible materials, comprising a radiation source for generating an electromagnetic beam, in particular a laser beam, a mirror deflection system deflecting the electromagnetic beam and a focusing lens. This device is characterized in that a diffractive optical element "DOE" is arranged in the beam path of the electromagnetic beam between the mirror deflection system and the focusing lens to split the beam path into two or more beam paths in order to generate a pattern of processing points on the material to be processed and/or to perform a positioning of the processing point or points on the material.

By dividing the laser beam into at least two, but preferably several beams of rays, a corresponding, simultaneous multiplication of the

Machining operation can be effected on the material in question.

By positioning the "DOE" in the beam path of the laser after the mirror deflection system and in front of the focusing lens, due to the resulting short beam length, the widening of the beam distances of the individual beams of rays can still be kept together to such an extent that even if the primary laser beam is deflected within the surface that can be painted over by the mirror deflection system, all individual beam bundles of the laser beam multiplied by the "DOE" can still be directed to the focusing lens and thus focused accordingly. The individual beams can also be arranged in different geometries and at different distances from one another.

Depending on the focal length of the focusing lens and the diffractive optics, for example, 8 focus points can be imaged in a line at a distance of 10 mm each (total 80mm).

The material to be processed can in particular be provided in the form of at least one material web for processing, which is fed from a material roll, for example.

The multiplied processing achieved in this way can be effected in particular even at high web running speeds of the material to be processed with a wide variety of, in particular flexible, materials. This allows a high degree of flexibility in relation to the number, arrangement and diameter of the laser processing of the material, in particular the production of holes, to be achieved. Many laser processes such as perforating, scribing, cutting, marking or structuring can be multiplied with this arrangement.

According to a preferred embodiment, the diffractive optical element is rotatable and/or pivotable in order to change a deflection angle of at least one of the two or more beam paths relative to another rotational and/or pivot position of the diffractive optical element.

This makes it possible, for example, to adjust the relevant beam alignment to the desired processing position on the material to be processed.

The diffractive optical element can do this, for. B. together with the focusing lens can be rotated and / or pivoted. Furthermore, it is possible for the diffractive optical element to align the beam paths at equal distances from one another. This allows, for example, several material processings to be carried out at equal distances from one another, for example perforation lines running parallel or the like.

It is also possible for the diffractive optical element to align the beam paths at different distances from one another. For example, different desired machining positions on the material to be machined can be taken into account. For example, material processing such as the formation of cuts, perforations and/or the like can be generated for structures with different partial geometries.

For this purpose, one embodiment can provide that the diffractive optical element divides the beam paths into the same geometries, in particular the same cross-sectional shapes of the beam paths.

Alternatively or additionally, the diffractive optical element can divide the beam paths into different geometries, in particular different cross-sectional shapes of the beam paths. This allows different processing operations to be carried out, such as the embossing of differently structured material removals. Those with small and/or comparatively only shallow material removals, for example by a laser spot with a comparatively small beam cross section.

In contrast, for example, by means of a beam cross section that is elongate—in the direction of movement of the material strip of the material to be processed—and thus longer continuous blasting effect on the material at the same point, a comparatively deeper material processing / deeper material removal is possible, in addition to the comparatively longer contour.

Furthermore, the diffractive optical element can be arranged on or on the focusing lens, in particular directly on or on the focusing lens.

As a result, the length of the beams between the "DOE" and the focusing lens can be kept extremely short. The individual structures of the "DOE" can also be formed very closely together. This in turn has a cost-reducing effect, in addition to enabling small geometries for the device and its individual components. Because diffractive optics "DOEs" become very expensive with increasing diameter.

According to one embodiment of the device, the focusing lens can be designed in the form of an F-Theta lens (far-field lens).

According to an alternative embodiment, the focusing lens can be in the form of a multi-lens system, in particular in the form of a telecentric lens. A telecentric lens has the advantage that the edge rays are better focused on the processing plane.

The one that deflects the electromagnetic beam

Mirror deflection system can be a 1-axis scanner or a multi-axis scanner, preferably a 2-axis scanner. In other words, in the case of the 2-axis scanner, a first mirror with an adjustable alignment is used to deflect the image and then by a second mirror whose orientation can also be adjusted. In principle, the primary laser beam can thus be directed to any point of an associated XY coordinate system.

The invention also relates to a

Beam multiplication device, comprising a housing, a mirror deflection system deflecting an electromagnetic beam, in particular a laser beam, and a focusing lens. This beam multiplication device is characterized in that a diffractive optical element "DOE" is arranged in the beam path of the electromagnetic beam between the mirror deflection system and the focusing lens.

The same effects can be achieved with this beam multiplication device as already explained above for the device for processing materials by means of electromagnetic radiation.

In the case of the beam multiplication device, it is also provided that the mirror deflection system that deflects the electromagnetic beam is preferably a 2-axis scanner.

Furthermore, the focusing lens is the

Beam multiplication device according to one embodiment in the form of an F-Theta lens.

According to an alternative embodiment of

Beam multiplication device, the focusing lens can also be designed in the form of a multi-lens system, in particular in the form of a telecentric lens. In the following, the invention is briefly described in other words as follows.

It relates to an arrangement of optical components, e.g. to introduce multiple perforations into a wide variety of flexible materials at high web speeds. A high degree of flexibility is achieved in relation to the number, arrangement and diameter of the holes. Many other laser processes, such as perforating,

Scoring, cutting, marking or structuring can be multiplied with this process.

Using a laser beam source in connection with a mirror deflection system (e.g. a scanner) and a focusing lens (e.g. an F-Theta lens) perforations, lines or free-form contours can be imaged on a plane. These can be used for marking, cutting, structuring or perforating different materials. This system is limited by the fact that only one laser beam hits the material.

However, if a laser beam, which is deflected in a mirror deflection system via preferably 2 mirrors in the x and y direction, then hits diffractive optics, also referred to as a diffractive optical element "DOE", then this diffractive optic divides the beam into several, depending on the design partial beams.

The individual beams can be arranged in different geometries and at different distances from one another. The laser beam is focused on the plane via the focusing lens, eg a so-called far-field lens (F-Theta lens). The position of the diffractive optics (DOE) is crucial.

If the DOE were installed in front of the deflection mirrors in the entrance of the scanner (aperture), then with increasing distribution of the individual rays (increasing distance between the focusing points), part of the radiation (marginal rays) would no longer hit the deflection mirrors in the scanner. This means that the edge area of the radiation would not be reflected via the deflection mirror but would be absorbed in the scanner housing and the full laser power could therefore no longer be available for the processing process.

Installing the DOE after the deflection mirrors has the advantage that the laser beam passes through the aperture of the scanner through the mirror deflection system as before and only then hits the DOE. Since the deflection positions in the x and y directions directly after the mirrors are still very small, the diameter of the DOE can be adapted to the beam diameter and the small change in position.

In addition, the diffractive optics become very expensive with increasing diameter.

After the diffractive optics, the individual beams generated by diffraction then hit the focusing lens, e.g. a far-field lens (F-Theta lens) and are focused from there on the processing plane.

Depending on the focal length of the focusing lens and the diffractive optics, for example, 8 focus points can be imaged in a line at a distance of 10 mm each (total 80mm). This would not be possible when installing the DOE at the entrance of a scanner and an aperture of 15 mm. The beam would already be at the DOE widened and would then already be too large at the deflection mirrors.

Instead of a far-field lens (F-Theta lens), a multi-lens system, such as a telecentric lens, can also be used to focus the laser beams. A telecentric lens has the advantage that the edge rays are better focused on the processing plane.

In addition: the use of a rotary axis is planned in order to be able to set the DOE (alone or together with the far-field lens) in different angular positions or to be able to rotate it.

The partial beams generated by the DOE can thus:

1) be placed at different angles in the axis of rotation.

If, for example, 8x focus points are imaged in a row at a distance of 10 mm in the processing plane via the DOE, 8 tracks can be cut, scored or holes created in pulse mode on a running material web.

When rotating the DOE, the distance between the lines becomes smaller. In the case of pulsed operation, the hole spacing becomes smaller in the direction of web travel and the holes are arranged in a staggered manner (different patterns possible).

A pattern can also be achieved, for example, by arranging the 8 focus points in the direction of web travel (8 hole spacing fixed by DOE) and the mirror deflection system has a different number of holes and freely selectable hole spacing transverse to the Web direction arranges.

2) The so-called "marking on the fly" (MOF) operation of a scanner enables the processing (e.g. marking, perforating, etc.) of individual and endless parts or material webs without distortion during movement (even at very high web speeds).

With the individual beams, for example, 8 circles lying one inside the other can be generated with only one circular movement of the mirror deflection system.

Even in pulsed operation of the laser, several holes can be created simultaneously without distortion (round) even at high web speeds.

A large number of applications (perforating, lines, free-form contours, etc.) could also be listed here. However, the principle always remains the same.

This process can also be used, for example, in the manufacture of cigarettes (light cigarettes) - keyword: tipping paper.

Description of an example:

The invention is described in more detail below by way of example with reference to the attached figures.

It shows as an example and schematically:

Figure 1: A device for processing materials by means of electromagnetic radiation, comprising a Radiation source for generating an electromagnetic beam, a deflecting electromagnetic beam

Mirror deflection system and a focusing lens, in which a diffractive optical element "DOE" is arranged in the beam path of the electromagnetic beam between the mirror deflection system and the focusing lens for splitting the beam path into two or more beam paths in order to generate a pattern of processing points on the material to be processed and /or to effect positioning of the edit point or points on the material.

FIG. 2: A beam multiplication device of a device for processing materials by means of electromagnetic radiation as in FIG. 1, with a focus on the structure of the components influencing the electromagnetic beam.

FIG. 3: An embodiment of a beam multiplication device that is modified compared to FIG.

In this sense, FIG. 1 shows a device 1 for processing materials 2 by means of electromagnetic radiation 3. The materials 2 to be processed are preferably flexible materials that can be moved, for example, as webs of material.

This device comprises a radiation source 4 for generating an electromagnetic beam 3, in particular a laser device for generating a laser beam, a mirror deflection system 5 deflecting the electromagnetic beam 3 and a focusing lens 6. In the beam path of the incident in the direction of arrow 3.1, electromagnetic beam 3 is between the

Mirror deflection system 5 and the focusing lens 6, a diffractive optical element "DOE" 7 for splitting the beam path into two or more beam paths 3, 3 'arranged to generate a pattern 2.2, 2.2' of processing points 2.1, 2.1 'on the material 2 to be processed and/or to bring about a positioning of the processing point 2.1 or the processing points 2.1, 2.1' on the material 2.

In the example shown, the processing points 2.1' are larger and further apart than the processing points 2.1 to reveal a flexible design option for the individual patterns 2.2, 2.2' that can be produced.

FIG. 2 shows symbolically and by way of example a beam multiplication device 10 with a housing 11, as can be part of the device 1 according to FIG. 1, for example. FIG. 2 further reveals that the diffractive optical element 7, as symbolically represented by the arrows 7.1.1, 7.2.1, is rotatable about a first axis 7.1 and/or pivotable about a second axis 7.2, about a deflection angle of at least one of the two or more beam paths 3, 3', 3'' in relation to another rotational and/or pivoting position of the diffractive optical element 7.

In this representation, the arrow 6.1.1 also symbolically reveals a rotatability of the focusing lens 6 . This can eg open up the possibility of a mechanical connection of the DOE 7 with the focusing lens 6, in which the DOE 7 can be rotated together with the focusing lens and their pattern influencing according to the movement possibility corresponding to one or both of the arrows 3.1.1, 7.2.1 can still be available. For example, the diffractive element 7 can be applied to the focusing lens 6 .

In this illustration, the mirror deflection system 5 is shown as a 2-mirror scanner by way of example. This comprises a first mirror unit 5.1, rotatable about an axis 5.1.1, with a mirror 5.1.2 and a second mirror unit 5.2, rotatable about an axis 5.2.1, with a mirror 5.2.2.

The mirror 5.1.1 deflects the electromagnetic beam 3 incident in the direction of the arrow 3.1, viewed in the image plane of FIG. 2 in regular view, coming from the right to the left, onto the second mirror 5.2.1 and this the electromagnetic beam downwards .

The diffractive element “DOE” 7 divides the primary electromagnetic beam into three beams 3.1.1, 3.1.1′, 3.1.1′″, again by way of example.

Figure 3 shows a similar embodiment of a beam multiplication device 10 as Figure 2. It differs from this in that the focusing lens 6 also has the properties of a diffractive element "DOEs" 7. I.e., the electromagnetic beam impinging on the focusing lens 6 from the mirror deflection system 5 3 is divided by its diffractive properties into two or more, in the example shown in three beams 3.1.1, 3.1.1 ',

3.1.1''' divided and then focused (cf. Fig. 1/Pos.

2.1, 2.2, 2.1, 2.2').

For the rest, the same position symbols in all figures represent the same features. List of references:

1 device

2 materials

2.1 Edit Point

2.2 Pattern

3 radiation

3.1 arrow

4 radiation source

5 mirror deflection system

5.1 Mirror Unit

5.1.1 Axis

5.1.2 Mirror

5.2 Mirror Unit

5.2.1 Axis

5.2.2 Mirror

6 focusing lens

6.1.1 Arrow

7 diffractive optical element "DOE"

7.1 Axis

7.1.1 Arrow

7.2 Axis

7.2.1 Arrow

10 beam multiplier device

11 housing

Claims

Expectations :

1) Device (1) for processing materials (2) by means of electromagnetic radiation (3), the materials to be processed preferably being flexible materials, comprising a radiation source (4) for generating an electromagnetic beam (3), in particular a laser beam mirror deflection system (5) deflecting the electromagnetic beam (3) and a focusing lens (6), characterized in that a diffractive optical element "DOE" ( 7) arranged to split the beam path (3) into two or more beam paths (3, 3', 3'') in order to generate a pattern (2.2) of processing points (2.1) on the material (2) to be processed and/ or to bring about a positioning of the processing point (2.1) or the processing points (2.1, 2.1') on the material (2).

2) Device for processing materials by means of electromagnetic radiation according to Claim 1, characterized in that the diffractive optical element (7) is arranged such that it can be rotated and/or pivoted in order to deflect at least one of the two or more beam paths (3, 3",

3'') relative to another rotational and/or pivoting position of the diffractive optical element (7).

3) Device for processing materials by means of electromagnetic radiation according to claim 1 or 2, characterized in that the diffractive optical element (7) together with the focusing lens (6) is rotatable and / or pivotable 4) Device for processing materials by means of electromagnetic radiation according to one of the preceding claims, characterized in that the diffractive optical element (7) aligns the beam paths (3, 3", 3'') at equal distances from one another.

5) Device for processing materials by means of electromagnetic radiation according to one of the preceding claims 1 to 3, characterized in that the diffractive optical element (7) aligns the beam paths (3, 3", 3'') at different distances from one another.

6) Device for processing materials by means of electromagnetic radiation according to one of the preceding claims, characterized in that the diffractive optical element (7) converts the beam paths (3, 3", 3") into the same geometries, in particular the same cross-sectional shapes of the beam paths (3 , 3",

3'') divides.

7) Device for processing materials by means of electromagnetic radiation according to one of the preceding claims 1 to 5, characterized in that the diffractive optical element (7) converts the beam paths (3, 3", 3") into different geometries, in particular different cross-sectional shapes of the beam paths (3, 3", 3").

8) Device for processing materials by means of electromagnetic radiation according to one of the preceding claims, characterized in that the diffractive optical element (7) is arranged on or on the focusing lens (6), in particular directly on or on the focusing lens. 9) Device for processing materials by means of electromagnetic radiation according to one of the preceding claims, characterized in that the focusing lens (6) is designed in the form of an F-Theta lens.

10) Device for processing materials by means of electromagnetic radiation according to one of the preceding claims 1 to 8, characterized in that the focusing lens (6) is designed in the form of a multi-lens system, in particular in the form of a telecentric lens.

11) Device for processing materials by means of electromagnetic radiation according to one of the preceding claims, characterized in that the electromagnetic beam (3) deflecting mirror deflection system (5) is a 1-axis scanner.

12) Device for processing materials by means of electromagnetic radiation according to one of the preceding claims 1 to 10, characterized in that the electromagnetic beam (3) deflecting mirror deflection system (5) is a multi-axis scanner, preferably a 2-axis scanner .

13) Beam multiplication device (10), comprising a housing (11), an electromagnetic beam (3), in particular a laser beam deflecting mirror deflection system (5) and a focusing lens (6), characterized in that in the beam path of the electromagnetic beam (3) between a diffractive optical element "DOE" (7) is arranged between the mirror deflection system (5) and the focusing lens (6). 14) beam multiplication device according to claim 12, characterized in that the diffractive optical element (7) is arranged rotatably, in particular together with the focusing lens (6).

15) Beam multiplication device according to claim 13 or 14, characterized in that the electromagnetic beam (3) deflecting mirror deflection system (5) is a 1-axis scanner. 16) Beam multiplication device according to claim 13 or 14, characterized in that the electromagnetic beam (3) deflecting mirror deflection system (5) is a multi-axis scanner, preferably a 2-axis scanner. 17) beam multiplication device according to any one of claims 12 to 14, characterized in that the focusing lens (6) is designed in the form of an F-Theta lens.

18) Beam multiplication device according to one of claims 12 to 15, characterized in that the focusing lens (6) is designed in the form of a multi-lens system, in particular in the form of a telecentric lens.