DE102013114489B3 - Device for the thermal processing of a workpiece - Google Patents

Abstract

Known devices for the thermal processing of a workpiece have a work table with a support surface for receiving the workpiece, a laser processing unit with a laser machining head, a moving unit with a machine gantry for moving the laser machining head in a gantry longitudinal direction and a transverse carriage for moving the Laser cutting head in a direction perpendicular to the longitudinal direction transverse direction at a predetermined working distance to the surface of the workpiece, as well as with the laser cutting head in the longitudinal and transverse direction movable protective hood. In order to indicate a device that enables high machine dynamics and at the same time ensures a high level of safety for the operating personnel, it is proposed according to the invention that at least one transversely extending, stationary beam catching device be connected to the workbench in such a way with respect to the support surface tiltable or retractable is that it surmounted the support surface maximum at the working height.

Description

Technical area

• • einen Arbeitstisch mit einer Auflagefläche für die Aufnahme des Werkstücks,
• • eine Laserbearbeitungseinheit mit einem Laserbearbeitungskopf,
• • eine Bewegungseinheit mit einem Maschinenportal zur Bewegung des Laserbearbeitungskopfs in einer Portal-Längsrichtung und einem Querwagen zur Bewegung des Laserbearbeitungskopfs in einer senkrecht zur Längsrichtung verlaufenden Querrichtung in einem vorgegebenen Arbeitsabstand zur Oberfläche des Werkstücks, und
• • eine mit dem Laserbearbeitungskopf in Längs- und Querrichtung bewegliche Schutzhaube.

The present invention relates to a device for the thermal processing of a workpiece by means of laser radiation, comprising

• A work table with a support surface for receiving the workpiece,
• A laser processing unit with a laser processing head,
• A movement unit with a machine gantry for moving the laser processing head in a gantry longitudinal direction and a transverse carriage for moving the laser machining head in a direction perpendicular to the longitudinal direction transverse direction at a predetermined working distance to the surface of the workpiece, and
• • a protective cover that can be moved longitudinally and transversely with the laser processing head.

Thermal processing devices according to the invention are used in particular for cutting or welding workpieces made of metal by means of a laser beam. In addition to a laser unit with a laser cutting or welding head, they have a movement unit which permits an at least two-dimensional movement of the laser cutting head over the workpiece.

State of the art

In known devices for the thermal processing of a workpiece as a moving unit is often provided in a longitudinal direction of the work table movable machine portal. The portal-like structure of the machine portal has a high mechanical stability, so that an exact and reproducible movement and positioning of the laser processing head is made possible. In addition, a transverse carriage is regularly connected to the machine portal, which allows movement in a direction perpendicular to the longitudinal direction transverse direction. As a result, the laser processing head can be moved by means of the movement unit over the entire surface of the work table.

Lasers, which are used for the thermal treatment of metallic workpieces, have a high radiation power. In principle, they pose a risk to the health of operating personnel, and especially to the organs, skin and eyes. When using laser radiation for cutting workpieces, therefore, protective measures must be taken to protect the operating personnel.

The degree of protection depends, among other things, on the type of laser used. In particular, when using fiber lasers that emit in a wavelength range of 1060 nm to 1070 nm, elaborate protective measures are necessary.

Thus, in known laser processing devices, full housings of the entire device are often provided which surround all sides of the device, including the top thereof. Full enclosures have the advantage that a radiation leakage can be largely excluded.

The provision of a full housing, however, comes with some disadvantages. When loading the device, the workpiece must first be moved to the full housing. An opening of the full enclosure is regularly possible only with a temporary standstill of the machine. In addition, the entire processing and machine area of the device can not be viewed directly, but only via cameras located within the full housing.

To reduce these downtime of the device while ensuring a high level of safety, is in the EP 2 468 446 A1 proposed a device in which the laser cutting head is surrounded on all sides by a mitverfahrbaren with the laser cutting head in the outer outer protective housing. Within the protective housing, a cutting carriage is arranged, which allows a movement of the laser cutting head in the transverse direction. The laser cutting head is also surrounded by a separate, movable along with the cutting car protective cover.

From the EP 0 900 623 A1 a Sicherheitsabschirmvorrichtung for a laser cutting machine with a movable machine portal is known. At the machine portal, a protective hood with at least one double protective wall is attached to shield the laser radiation. In order to minimize the emission of laser radiation, height-adjustable beam-catching devices are furthermore provided on the protective hood, so that the smallest possible distance between the protective hood and the workpiece can be set.

EP 0 962 278 A2 discloses a laser cutting machine comprising a machine gantry, a worktable with support bars and a protective hood. In order to avoid leakage of reflected laser radiation through open surfaces of the work table in a work table not completely occupied with workpieces, in the EP 0 962 278 A2 proposed to install additional vertical Abschirmstege below the support bars.

Technical task

The use of a longitudinally mitverfahrbaren outer protective housing, which surrounds the laser cutting head on all sides, is associated with a high weight, which must be moved with a movement of the moving unit; The weight reduces the achievable machine dynamics and can also affect the exact and reproducible movement of the laser cutting head.

The invention is therefore based on the object to provide a laser processing device that allows high machine dynamics while ensuring a high level of security for the operator.

General description of the invention

This object is achieved on the basis of a device for the thermal processing of a workpiece of the type mentioned in the present invention that is connected to the work table at least one extending at least in the transverse direction beam catching device that is so tilted or retractable in relation to the support surface that the laser processing head is movable over the beam catcher.

In known devices for the thermal processing of a workpiece protection of the operator is ensured by the fact that the protective device comprises two elements. In these devices, the laser processing head is provided on the one hand with a mitbewegbaren with the cross car inner protective cover, on the other hand, is enclosed on all sides by a mitverfahrbaren in the longitudinal direction outer protective housing.

The inner protective cover is moved in one movement together with the laser processing head supported on the cross carriage. In order to ensure good mobility of the laser processing head and in particular to avoid a collision between the inner protective cover and the workpiece, it is necessary that a certain gap remains between the inner protective cover and the workpiece surface.

Since this gap is transparent to laser radiation, the laser processing head and the inner protective cover are arranged in the outer protective housing. This is regularly enclosed on all sides to prevent the escape of radiation as effectively as possible. However, the outer protective housing must be moved regularly during a movement of the laser processing head. In particular, an outer protective housing, which surrounds the laser processing head on all sides, has a high weight, and therefore may affect the machine dynamics.

In contrast, two modifications are provided in the device according to the invention, one of which relates to the provision of a beam-catching device and the other relates to the use of a protective hood which surrounds the laser processing head. The protective hood surrounds the laser processing head in particular upwards and at the sides. As a result, a large portion of emerging laser radiation is already intercepted directly at the laser processing head, so that any other radiation protection measures must be less complex, such as another, the inner protective cover surrounding outer protective hood, which may remain open at the top.

In addition, a "stationary" beam catcher is provided according to the invention, which is connected to the work table, for example in the form of a mudguard. The term "stationary" is understood to mean an arrangement of the beam-catching device in which the beam-catching device is not moved together with the moving unit during a movement of the moving unit. The "stationary" beam catcher is mechanically connected at least on one side to the work table, preferably with its front side running parallel to the machine portal. In the simplest case, the mechanical connection is made by simple contact between beam catcher and work table ensured. Although it is possible to dispense with this, but this is not preferred, since, if necessary, a gap open between laser beam and work table for laser radiation arises.

The "stationary" beam catcher is thus connected to the work table so that extends at least in the transverse direction, but preferably surrounds the work table on all sides and is particularly preferably also connected on all sides with the work table.

Since, in particular, reflected laser radiation or scattered radiation emerges from the gap between the protective hood and the workpiece surface with a flat reflection angle relative to the workpiece surface, this radiation can easily be captured by means of the beam catching device in the sense of the invention. For this purpose, it is necessary that the beam catching device projects beyond the workpiece surface or bearing surface.

The minimum height at which the beam catcher should project beyond the workpiece surface for effective protection can be determined, for example, by the following equation:

h_SE:

die Mindesthöhe der Strahlfangeinrichtung,

h_Sp:

die Höhe des Spalts zwischen Auflagefläche und Schutzeinrichtung,

A_{max,(Laser-SE)}:

der maximal einstellbare Abstand zwischen dem Auftreffpunkt des Laserstrahls auf der Werkstückoberfläche und Strahlfangeinrichtung, und

A_(Laser-Sp)

der Abstand zwischen dem Auftreffpunkt des Laserstrahls auf der Werkstückoberfläche und dem Spalt zwischen Werkstückoberfläche und Schutzeinrichtung.

Where:

h _SE :

the minimum height of the beam-catching device,

h _Sp :

the height of the gap between the bearing surface and the protective device,

A _{max, (laser SE)} :

the maximum adjustable distance between the point of impact of the laser beam on the workpiece surface and beam catcher, and

A _{(laser sp)}

the distance between the point of impact of the laser beam on the workpiece surface and the gap between the workpiece surface and the protective device.

The free working distance is the smallest distance of the laser processing head to the support surface. In compliance with the free working distance - unless undermined by any rigid components of the movable guard - undisturbed movement of the laser processing head and the surrounding protective cover over the entire bearing surface of the work table guaranteed.

The height of the beam catcher is greater than the working distance between the laser processing unit and the support surface, so that the beam catcher plate opposes a movement of the processing unit or the laser processing head on the beam catcher. Therefore, the invention provides that the beam catcher can be tilted or sunk at a height less than the working distance. In the tilted or recessed state, the beam-catching device has a height relative to the support surface that is less than the working distance between the laser-processing unit and the support surface. In this way, a free movement of the laser processing head over the entire support surface of the work table is made possible in the tilted or recessed state.

The beam-catching device is dimensioned such that it is tiltable or retractable with respect to the support surface in such a way that, in the recessed or tilted state, it projects beyond the support surface at a height which is less than the working distance between the laser processing unit and the support surface.

A further improvement results when the beam-catching device has a lower end section connected to the work table and an upper end section projecting above the work table, wherein the upper end section of the beam-catching device is at an angle in the range of 80 ° to 180 °, preferably at an angle of 90 ° , is angled relative to the lower end portion in the direction of the laser processing unit.

The angled beam catcher catches the radiation impinging thereon particularly effectively. At an angle of the beam catcher of less than 80 ° or more than 180 ° loses their effectiveness.

It has proved to be advantageous if the beam catching device has a Y- or T-shaped profile.

Beam-catching devices with a Y- or T-shaped profile show good beam-tracing characteristics regardless of the side from which the radiation impinges on the beam-catching device. The beam-catching devices can be arranged at one end of the work table or in the middle region of the work table. From a beam catcher arranged in the middle region of the work table, the support surface of the work table is basically subdivided into two separate work areas. It has proven particularly useful if the beam catching devices arranged in the middle region have a Y-shaped or T-shaped profile. As a result, regardless of which working area the laser cutting head is currently assigned, a sufficient function of the beam catching devices is ensured.

Preferably, the beam catcher is made of steel or aluminum and has a thickness in the range of 1 mm to 5 mm.

A beam catcher made of steel or aluminum has a high resistance to incident laser radiation. In particular, the thickness of the beam catcher affects their resistance; It also has an influence on the mechanical stability of the beam catcher. A beam-catching device with a thickness of less than 1 mm has a low mechanical stability and can withstand the incident laser radiation only to a limited extent. A beam-catching device with a thickness of more than 5 mm is associated with high manufacturing costs for the device.

In another, preferred embodiment of the device according to the invention a plurality of spaced apart beam catcher is connected to the work table for the division of several work areas on the support surface.

Several beam catching devices allow a subdivision of the support surface into a plurality of separate work areas, each of which can be provided with a workpiece. The work area to which the laser cutting head is assigned is called a machining area. By the beam catcher and the guard for each assignment of the laser cutting head to a work area such a good laser protection ensures that during processing of a first workpiece in the processing area simultaneous loading of other work areas is possible.

It has proved useful if the beam-catching devices run parallel to one another, and if adjacent beam-catching devices have a spacing in the range of 4000 mm to 20,000 mm from each other.

Beam catching devices running parallel to each other define a square or rectangular working area on the support surface; In another preferred modification of the device, it is provided that the machine gantry comprises a transverse bridge with a side facing the transverse carriage and a side facing away from the transverse carriage, and that the protective hood on the side facing the transverse carriage is a shielding element extending completely in the transverse direction of the support surface upstream, which is movable with the machine portal in the longitudinal direction.

In contrast to an all-round housing, a shielding element has a lower weight. At the same time, a shielding element exhibits a good shielding effect for emerging laser radiation and contributes to a high degree of safety for the operating personnel of the device.

It has proved to be advantageous if the shielding element extends at least partially perpendicular to the support surface and has an angling in the direction of the laser processing unit in an angular range of 100 ° to 175 °.

An angled shield also exhibits an improved shielding effect over a non-angled shield. It has been shown that a good shielding effect can be achieved, in particular with an angling in the abovementioned angular range. The bend also contributes to a mechanical stabilization of the shielding. In order to increase the mechanical stability of the shielding element, the shielding element may also be provided with a fold or a bead.

A further modification of the device according to the invention provides that the machine gantry comprises a transverse bridge with a side facing the transverse carriage and a side facing away from the transverse carriage, and in that the movable protective hood faces the bridge on its side Rear side is designed to be open, wherein the open back is associated with a completely extending in the transverse direction of the support surface and extending parallel to the bridge additional protective wall.

The fact that the protective hood is designed to be open at the back, the weight of the guard can be reduced, which must be moved during a movement of the cross carriage. This allows a high machine dynamics and an exact and reproducible adjustment of the transverse carriage. In order to achieve a sufficient shielding effect at the same time, an additional protective wall extending parallel to the bridge is provided, which is moved longitudinally together with the machine portal.

In an advantageous embodiment of the device according to the invention, the laser processing unit has a fiber laser with an emission wavelength in the range of 1060 nm to 1080 nm.

The limits for laser radiation in the visible and in the NIR range are much lower than for other optical radiation. In particular, when using fiber lasers that emit in the above range, extensive radiation protection, as guaranteed by the device according to the invention, is necessary.

It has proven useful if the shielding element and / or the protective wall have on their underside a curtain which seals a gap to the workpiece surface.

A curtain contributes to the effective sealing of a gap remaining between the workpiece surface and the device. Such a curtain is subjected to high mechanical stresses during operation; It has therefore proven useful when the curtain has a high mechanical stability. In addition, the curtain must have some flexibility to ensure adequate sealing of the gap.

In this context, it has proven to be advantageous if the curtain is made of a flexible fabric, in which a connected to a safety circuit metal wire is incorporated.

A fabric has a high mechanical stability and good flexibility. However, even such a curtain is heavily used with increasing duration of use. In order to avoid that the device is operated with a damaged curtain, a metal wire is incorporated into the curtain, which is connected to an electrical safety circuit. Damage to the fabric is regularly accompanied by damage to the metal wire. In this case, the safety circuit is interrupted, so that the damage of the curtain can be easily detected.

Furthermore, it has proven useful if the curtain comprises a plurality of side by side and laterally offset successively arranged pieces of tissue, each with a metal wire connected to a safety circuit.

Several side by side and laterally offset successively arranged tissue pieces increase the barrier effect of the curtain for incident radiation. The fact that the tissue pieces are each connected to a safety circuit, smaller damage to the curtain can be detected and located easily and quickly.

embodiment

The invention will be described in more detail with reference to embodiments and four figures. In detail shows in a schematic representation:

1 a first embodiment of the inventive device for the thermal processing of a workpiece in perspective view,

2 the embodiment of the device according to the invention according to 1 in section,

3 a second embodiment of the device according to the invention for the thermal processing of a workpiece with a plurality of beam trapping devices in plan view,

4 an embodiment of the curtains, and

5 a third embodiment of the device according to the invention.

1 schematically shows a laser cutting machine, the total reference numeral 100 assigned. The laser cutting machine 100 is used for cutting flat workpieces made of metal.

It includes a worktable with a (L x B) 4000 mm x 12.000 mm (in 1 through lines 101 . 101b shown), a laser processing unit 102 with a fiber laser and a laser cutting head 102 as well as a machine portal 103 with a cross carriage 104 , The laser cutting head 102 is with the cross carriage 104 connected so that this together with the cross carriage 104 can be moved. The machine portal 103 with cross carriage 104 has a biaxial serial displacement kinematics, which is a movement of the laser cutting head 102 longitudinal 106 and in the transverse direction perpendicular to the longitudinal direction 105 allows. Through the machine portal 103 and the cross car 104 can the laser cutting head 102 be moved at a predetermined working distance to the surface of the workpiece.

In order to avoid leakage of laser radiation during the cutting process, the laser cutting machine has a plurality of radiation protection devices. Such is the laser cutting head 102 below a protective hood 107 arranged. The protective hood 107 is on the cross carriage 104 attached; she gets over the machine portal 103 together with the laser cutting head 102 in the longitudinal and transverse directions 105 . 106 emotional; It is made of aluminum and includes two side plates 107a . 107b and a front plate 107c , The protective hood 107 is 500 mm high. On the machine portal 103 facing side, the guard is open.

In addition, to ensure an effective protective housing of the laser cutting head, which is the transverse carriage side facing away from the machine portal 103 an additional protective wall (not shown; 2 : 201 ) in the form of one with the machine portal 103 associated sheet associated, which extends transversely across the work table and in the longitudinal direction 106 together with the machine portal 103 can be moved. The sheet has a length of 5,000 mm at a height of 1,000 mm; It is made of aluminum.

Furthermore, the protective hood 107 a shielding element in the form of a shielding plate 108 upstream, that via side panels 108c . 108d with the machine portal 103 connected and together with this in the longitudinal direction 106 is movable. The shielding plate 108 is made of aluminum and has a plate thickness of 2 mm. Here is the shield 108 angled at an angle of 45 °. The shielding plate 108 and the side panels 108c . 108d Can be moved up to provide easy access to the laser cutting head 102 to enable

By having both the protective hood 107 as well as the protective wall sheet metal and the shielding plate 108 by means of the machine portal 103 can be moved over the surface of the workpiece, these components with respect to the support surface regularly at a distance. In order to prevent laser radiation from escaping from the resulting gap, the outer components, namely the protective wall plate and the shielding plate, are 108 , on its underside facing the workpiece surface, with a curtain (not shown; 2 : 202a . 202b ), which seals the gap. In an alternative embodiment (not shown), the protective hood is also provided with a curtain on its underside facing the material surface.

Particularly effective is an undesirable leakage of laser radiation through an associated with work table beam catching device in the form of the beam-catching plate 110 prevented. The jet catcher 110 extends from the support surface of the work table initially perpendicular to the support surface. This section is followed by a 90 ° angled end section (not shown). The jet catcher 110 extends completely in the transverse direction 105 the bearing surface. The jet catcher 110 has a height of 700 mm. For a simple and fast movement of the laser cutting head 102 and the machine portal 103 over the jet catcher plate 110 to allow the jet catcher 110 to the bearing surface along the axis of rotation 111 be tilted.

The height of the jet catcher plate 110 is greater than the working distance. For a simple and fast movement of the laser cutting head 102 and the machine portal 103 over there jet catcher 110 to allow the beam-catching plate can be sunk against the support surface alternatively.

The jet catcher 110 divides the bearing surface into several working areas, for example into a loading area and a cutting area. It helps to load the loading area during operation of the laser cutter 100 can be made, so that at the same time short production times and efficient operation of the device 100 be enabled.

2 schematically shows the laser cutting machine 100 out 1 in section. The laser cutting machine 100 includes a work table 101 , a machine portal 103 and a laser processing unit 102 with a laser cutting head 102 ,

The laser cutting head is in the direction 203 height adjustable, allowing the adjustment of the working distance e between laser cutting head 102 and workpiece surface is made possible. The laser cutting head 102 is surrounded by a protective housing. This includes the protective cover which can be moved transversely with the laser cutting head 107 , the protective wall 201 , the shielding plate 108 and those with the shielding plate 108 and the protective wall 201 connected curtains 202a . 202b ,

The work table 101 has a bearing surface for the workpiece 204 on, by several support webs 206 is formed. The support webs differ in their web height; They are designed to be either at the bottom of the table 207 reflected radiation 205 in the protective hood 107 is reflected back or absorbed.

To shield from the protective housing exiting radiation is also with the work table a beam catcher plate 110 connected to the workpiece 204 surmounted.

The jet tracer plate, designated "A" 110 in 2 is angled at 90 ° in the direction of the laser processing unit. Good results are also achieved when the jet tracer 110 has a bend with a different angle. With the reference symbols B, C, D, E and F are in 2 Alternative embodiments of the jet-catching plate shown in profile. The designated B beam landing plate has an angled portion at an angle of 135 °. C and D show alternative embodiments of the jet trapping plate 110 with a Y- or T-shaped profile. Figure E shows an alternative embodiment of the jet-trapping sheet that can be tilted. Figure F shows a jet catch plate in the retracted state.

In 3 is a further embodiment of a device according to the invention shown in plan view. The device is altogether the reference numeral 300 assigned.

The device 300 includes a work table 301 with a bearing surface for one or more workpieces. With the work table 301 are several jet trapping plates 302 . 303 . 304 . 305 . 306 connected. All jet traps 302 - 306 have the same height; it is 700 mm (measured from the support surface). The working distance between laser cutting head and workpiece surface can be adjusted. It is at least 0.3 mm.

Through the jet traps 302 - 306 the support surface is divided into four sections A-D, each of which defines a working area on the support surface. The size of the support surface is 16,000 mm × 4,000 mm (L × W). The faces A-D are the same size; their area is 4,000 mm × 4,000 mm (I × B) in each case.

Characterized in that a plurality of work areas are provided, a machining of a workpiece in a first work area, for example in part C, allows and at the same time allows loading of another part surface (for example A, B or D) with a new workpiece.

In addition, the device comprises a longitudinal direction 309 movable machine portal 307 with a bridge 308 and one at the bridge 308 fastened in transept 312 for moving the laser cutting head 310 in the transverse direction 311 ,

The jet traps 302 . 306 have an L-shaped profile and are angled in the direction of the laser processing unit at an angle of 90 °. The jet traps 303 . 304 . 305 have a T-shaped profile. As a result, a good jet shielding is ensured regardless of the position of the machine portal for each of the partial surfaces A-D.

4 shows an embodiment of a curtain 400 as in the device according to 1 is used. The curtain 400 intended to leak laser radiation from a gap between a moving component device 100 and reduce the workpiece surface.

The curtain 400 is made of several fabric pieces 401 -L made of fireproof fabric. The individual pieces of tissue 401 -L are made by interweaving non-conductive threads; they have good flexibility with high mechanical stability.

The tissue pieces 401 -L are juxtaposed and arranged in three rows laterally offset one behind the other. This allows the most complete possible radiation shielding. Into the pieces of tissue 401 -L is a metal wire 402a -L incorporated, which is connected to a safety circuit. For simplicity, in 4 only the metal wires 402a -D drawn; the metal wires 402e -L are corresponding to the pieces of tissue 401e -L incorporated. The metal wires 402a -L are made of copper and has a wire cross-section of 0.25 mm ² .

If the fabric is worn, for example as a result of mechanical stress or aging, the metal wire is also damaged so that the safety circuit is interrupted. This allows easy detection of damaged tissue.

5 shows an embodiment of the device according to the invention with a laser processing unit, comprising a laser cutting head 500 and a rigid protective hood 501 , On the protective hood 501 is a moving curtain 502 attached. Furthermore, the device comprises a work table 504 with a bearing surface for the workpiece 503 ,

In order to ensure good mobility of the laser processing unit, a gap remains between the lower end of the curtain and the workpiece through which radiation can escape from the protective hood. The height of the gap h _Sp , the distance between the point of impact of the laser beam on the workpiece surface and the beam catcher A _{(laser SE)} and the distance between the point of impact of the laser beam and the gap A _{(laser Sp)} set the minimum height of the beam catcher h _SE firmly.

h_frei:

freier Arbeitsabstand zwischen Laserbearbeitungseinheit und Auflagefläche,

h_max:

freier Abstand zwischen Laserbearbeitungseinheit und Werkstückoberfläche,

h_W:

Höhe des Werkstücks,

wobei h_kipp die Höhe der Strahlfangeinrichtung nach dem Verkippen beziehungsweise Versenken derselben darstellt. 5 shows the following example:
The working height h _{work, II of} the beam-catching device is greater than the free working distance between laser processing unit and bearing surface (h _work > h _free ):
The following applies: h _free = h _max + h _W With h _tilt <h _free With

h _free :

free working distance between laser processing unit and support surface,

h _max :

free distance between laser processing unit and workpiece surface,

h _W :

Height of the workpiece,

where h _{tilt represents} the height of the beam catcher after tilting or sinking the same.

Claims (13)

Contraption ( 100 ; 300 ) for the thermal processing of a workpiece ( 204 ; 503 ) by means of laser radiation, comprising • a work table ( 101 ; 301 ; 504 ) with a support surface for receiving the workpiece ( 204 ; 503 ), • a laser processing unit ( 102 ) with a laser processing head ( 102 ; 502 ), • a movement unit with a machine portal ( 103 ) for moving the laser processing head ( 102 ) in a portal longitudinal direction ( 106 ) and a cross carriage ( 104 ) for moving the laser processing head ( 102 ) in a direction perpendicular to the longitudinal direction ( 106 ) extending transverse direction ( 105 ) at a predetermined working distance to the surface of the workpiece ( 204 ; 503 ), and • one with the laser processing head ( 102 ) in the longitudinal and transverse directions ( 106 . 105 ) movable protective cover ( 107 ; 501 ), characterized in that with the work table ( 101 ; 301 ; 504 ) at least one at least in the transverse direction ( 105 ) running beam catching device ( 110 ; 302 ; 303 ; 304 ; 305 ; 306 ) which is tiltable or retractable with respect to the support surface in such a way that the laser processing head ( 102 ) via the beam catcher ( 110 ; 302 ; 303 ; 304 ; 305 ; 306 ) is movable. Contraption ( 100 ; 300 ) according to claim 1, characterized in that the at least one beam-catching device ( 110 ; 302 ; 303 ; 304 ; 305 ; 306 ) one with the work table ( 101 ; 301 ; 504 ) connected lower end portion and a work table ( 101 ; 301 ; 504 ) has superior upper end portion, wherein the upper end portion of the at least one beam catching device ( 110 ; 302 ; 303 ; 304 ; 305 ; 306 ) by an angle in the range of 80 ° to 180 ° relative to the lower end portion in the direction of the laser processing unit ( 102 ) is angled. Contraption ( 100 ; 300 ) according to claim 1, characterized in that the at least one beam-catching device ( 110 ; 302 ; 303 ; 304 ; 305 ; 306 ) has a Y- or T-shaped profile. Contraption ( 100 ; 300 ) according to one of the preceding claims, characterized in that the beam-catching device ( 110 ; 302 ; 303 ; 304 ; 305 ; 306 ) is made of aluminum and has a thickness in the range of 1 mm to 5 mm. Contraption ( 100 ; 300 ) according to one of the preceding claims, characterized in that for the division of a plurality of work areas on the support surface a plurality of mutually spaced beam-catching devices ( 110 ; 302 ; 303 ; 304 ; 305 ; 306 ) with the work table ( 101 ; 301 ; 504 ) are connected. Contraption ( 100 ; 300 ) according to claim 5, characterized in that the beam trapping means ( 110 ; 302 ; 303 ; 304 ; 305 ; 306 ) parallel to each other, and that adjacent beam trapping devices ( 110 ; 302 ; 303 ; 304 ; 305 ; 306 ) have a distance in the range of 4000 mm to 20,000 mm to each other. Contraption ( 100 ; 300 ) according to one of the preceding claims, characterized in that the machine portal ( 103 ) one in the transverse direction ( 105 ) running bridge with a cross carriage ( 104 ) and one the transverse carriage ( 104 ) facing away, and that the protective hood ( 107 ) on the cross carriage ( 104 ) facing side completely in the transverse direction ( 105 ) the support surface extending shielding ( 108 ), which is connected to the machine portal ( 103 ) longitudinal ( 106 ) is movable. Contraption ( 100 ; 300 ) according to claim 7, characterized in that the shielding element ( 108 ) extends at least partially perpendicular to the support surface and a bend in the direction of the laser processing unit ( 102 ) in an angular range of 100 ° to 175 °. Contraption ( 100 ; 300 ) according to one of the preceding claims, characterized in that the machine portal ( 103 ) one in the transverse direction ( 105 ) running bridge with a cross carriage ( 104 ) and one the transverse carriage ( 104 ) facing away, and that the movable protective cover ( 107 ) has a guard facing the bridge back, which is made open, and that the device is a completely in the transverse direction ( 105 ) extending the support surface and extending parallel to the bridge additional protective wall ( 201 ) associated with the open back of the protective cover. Contraption ( 100 ; 300 ) according to one of the preceding claims, characterized in that the laser processing unit ( 102 ) has a fiber laser with an emission wavelength in the range of 1060 nm to 1080 nm. Contraption ( 100 ; 300 ) according to one of the preceding claims 7 or 9, characterized in that the shielding element ( 108 ) and / or the protective wall ( 201 ) on its underside a curtain ( 400 ; 502 ) which seals a gap to the workpiece surface. Contraption ( 100 ; 300 ) according to claim 11, characterized in that the curtain ( 400 ; 502 ) is made of a flexible fabric, in which a connected to a safety circuit metal wire is incorporated. Contraption ( 100 ; 300 ) according to claim 11 or 12, characterized in that the curtain ( 400 . 502 ) several side by side and laterally offset successively arranged pieces of tissue ( 401 -L) each with a metal wire connected to a safety circuit ( 402a -L includes.

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