Focusing optics, laser machine and methods for processing a variety of workpieces

Abstract

Focusing optics (10) for processing, in particular circumferential welding or circumferential hardening, a workpiece (12) using an annular laser beam (18). The focusing optics (10) comprises: a housing (20) that partially surrounds a working chamber (30) of the focusing optics (10); a mirror (38) for deflecting the annular laser beam (18) radially inwards onto the workpiece (12) when the workpiece (12) is arranged in the working chamber (30) and a longitudinal axis (24) of the workpiece (12) is aligned collinearly with an optical axis (40) of the mirror (38); a first recess (46) for inserting the workpiece (12) into the working chamber (30); and a second recess (48) for removing the workpiece (12) from the working chamber (30). The work space (30) is arranged between the first recess (46) and the second recess (48).

Description

[0001] The invention relates to a focusing optic, a laser machine and a method for processing a large number of workpieces.

[0002] For welding cylindrical workpieces or for creating ring-shaped welds on cylindrical workpieces (circular welding), a focusing optic in the form of a ring focus optic or a rotary optic is frequently used. Such focusing optics are often cylindrical and have an opening at one end through which the workpieces to be welded are inserted into and removed from the working chamber of the focusing optic.

[0003] When processing a large number of workpieces with a ring focus optic or a rotary optic, the workpieces are typically inserted individually into the work area through the opening, illuminated with a laser beam, and removed from the work area through the same opening. Insertion and removal from the work area are performed through the same opening. The workpiece is usually moved parallel to the direction of propagation of the laser beam to insert or remove it from the work area.

[0004] The invention aims to provide a focusing optic, a laser machine and a method for processing a large number of workpieces, each of which has improved properties, in particular enabling the processing of a large number of workpieces in a short time and being suitable for mass production.

[0005] The invention solves this problem by providing a focusing optic with the features of claim 1, a laser machine with the features of claim 8, and a method with the features of claim 9. Advantageous further developments and / or embodiments of the invention are described in the dependent claims.

[0006] A focusing optic according to the invention is designed for processing, in particular circumferential welding or circumferential hardening, a workpiece using an annular laser beam. The focusing optic comprises a housing, a mirror, a first recess, and a second recess. The housing partially surrounds a working chamber of the focusing optic. The mirror is designed to deflect the annular laser beam radially inward onto the workpiece, particularly when the workpiece is arranged in the working chamber and a longitudinal axis of the workpiece is collinear, in particular congruent, coincident, or superimposed, with an optical axis of the mirror. The first recess is designed for inserting the workpiece into the working chamber. The second recess is designed for removing the workpiece from the working chamber. The working chamber is arranged between the first recess and the second recess.

[0007] Advantageously, the first and second recesses facilitate the insertion and removal of the workpiece from the work area. Preferably, this allows the workpiece to be machined using the focusing optics without requiring complex movements. In particular, deceleration or acceleration of the workpiece is eliminated. This reduces machining time and allows the focusing optics to be easily integrated into mass production systems.

[0008] The focusing optics can be referred to as ring focusing optics or ring optics.

[0009] Circumferential welding can be understood as the production of a continuous weld seam. The weld seam can be ring-shaped. Circumferential welding can also be laser transmission welding.

[0010] Circumferential hardening can be understood as hardening in a circumferential area of ​​the workpiece. This circumferential area can be ring-shaped.

[0011] The workpiece can be round. The workpiece can be cylindrical. Machining can take place within a ring-shaped section of the workpiece. The workpiece can be made of plastic. The workpiece can consist of a first part and a second part, which are to be welded together using the focusing optics. Both the first part and the second part can be made of plastic.

[0012] An annular laser beam can be understood as having a ring-shaped intensity profile. The annular laser beam can propagate along a direction parallel to the optical axis of the mirror. The beam axis of the laser beam can be collinear, in particular coincident, superimposed, or superimposed, with the optical axis of the mirror.

[0013] The focusing optics can include a cone-shaped mirror for shaping a laser beam into a ring-shaped laser beam.

[0014] The focusing optics can include a lens for focusing the ring-shaped laser beam onto the workpiece when the workpiece is positioned in the work space and a longitudinal axis of the workpiece is aligned collinearly to the optical axis of the mirror.

[0015] The housing can be hollow cylindrical. The housing can be elongated. The housing can extend along a longitudinal axis. The housing can have a laser beam opening at a first free end for directing the laser beam into the focusing optics. The housing can have a workpiece opening at a second free end for moving the workpiece towards or away from the work area. The first and second free ends can be opposite each other. The first and second openings can each be located at the workpiece opening. In particular, the first and second openings can each be adjacent to the workpiece opening. In other words, the first opening, the second opening, and the workpiece opening can form a single opening that is arranged segmentally at the second free end.

[0016] The workspace can be an interior space within the housing. The workspace can be accessible from the outside via the workpiece opening, the first recess, and the second recess.

[0017] The first and second recesses can be arranged on a lateral surface of the focusing optics, particularly the housing. Preferably, the first and second recesses can be arranged on a lateral surface of the focusing optics, particularly the housing. The first and second recesses can extend radially outwards from the optical axis of the mirror.

[0018] The first recess and / or the second recess can extend to the second free end of the housing. The first recess and / or the second recess can be groove-shaped; in particular, the first recess and / or the second recess can be grooves. The first recess and the second recess can each extend through the housing and through the mirror. The first recess and the second recess can be arranged relative to each other such that an imaginary straight line extending from the first recess to the second recess and perpendicular to the optical axis of the mirror intersects the optical axis of the mirror.

[0019] The mirror can be ring-shaped. The mirror can have a reflective surface with a reflectance of over 95%, preferably 98%, for a wavelength of the laser beam. The reflectance of the mirror surface can be at most 100% for the wavelength of the laser beam.

[0020] The mirror can be designed to illuminate the workpiece with the ring-shaped laser beam in such a way that the workpiece is arranged in the working space and a longitudinal axis of the workpiece is aligned collinearly to the optical axis of the mirror, such that a section of the workpiece is illuminated with a circumferential and / or ring-shaped spot.

[0021] The optical axis of the mirror can be aligned parallel to the longitudinal axis of the housing.

[0022] In a further development of the focusing optics, the first and second recesses are designed as two separate or independent recesses. By designing the first and second recesses as two separate recesses, it is possible to prevent the workpiece from being inserted into and removed from the work area via the same recess. In particular, this prevents the workpiece movement path for insertion into the work area and the workpiece movement path for removal from the work area from being identical, especially from having the same path.

[0023] In a further development of the focusing optics, the first and second recesses are arranged relative to each other such that the workpiece can be inserted into the workspace through the first recess and removed from the workspace through the second recess with a single, and preferably one, straight movement. This avoids the need to change the direction of movement during insertion and removal of the workpiece. Advantageously, this allows the workpiece to be moved from the first recess to the second recess at a continuous speed and / or in one continuous movement, and to be machined during this movement. In other words, the focusing optics enable machining of the workpiece while performing the straight movement.

[0024] The linear motion can be continuous. The linear motion can be performed at a constant speed. The linear motion can occur in a direction perpendicular to the optical axis of the mirror.

[0025] In a further development of the focusing optics, the mirror has a first reflective surface and a second reflective surface. The first and second reflective surfaces are separated from each other by the first and second cutouts. This allows the focusing optics to be designed compactly.

[0026] The first and second mirror surfaces cannot be adjacent. The first and / or the second mirror surface can be composed of sub-surfaces. The sub-surfaces of the first and / or the sub-surfaces of the second mirror surface can be arranged relative to each other in such a way that, when viewed parallel to the optical axis, they appear as a single, continuous surface. In particular, the sub-surfaces of the first mirror surface can appear as a single, continuous surface to the laser beam. The sub-surfaces of the second mirror surface can appear as a single, continuous surface to the laser beam.

[0027] The first mirror surface can be designed to direct part of the laser beam onto the workpiece in such a way that the workpiece is illuminated at an angle of 180° when the workpiece is arranged in the working space and the longitudinal axis of the workpiece is aligned collinearly with an optical axis of the mirror.

[0028] The second mirror surface can be designed to direct part of the laser beam onto the workpiece in such a way that the workpiece is illuminated at an angle of 180° when the workpiece is arranged in the working space and the longitudinal axis of the workpiece is aligned collinearly with an optical axis of the mirror.

[0029] The first mirror surface and / or the second mirror surface can have a shape that is section by section equal to a surface segment of a lateral surface of a truncated cone.

[0030] In a further development of the focusing optics, the first mirror surface borders the first recess and the second recess. The second mirror surface borders the first recess and the second recess. Advantageously, this allows a high proportion of the laser beam to be directed onto the workpiece.

[0031] In a further development of the focusing optics, the first mirror surface has a first region, a second region, and a third region. The second mirror surface also has a first region, a second region, and a third region. The second region of the first mirror surface is positioned between the first region and the third region of the first mirror surface. The first region and the third region of the first mirror surface are stepped. The first region and the third region of the second mirror surface are also stepped. This stepped design of the first and third regions ensures that the ring-shaped laser beam produces a ring-shaped spot on the workpiece.In particular, the workpiece is illuminated all around by means of the laser beam.

[0032] In a further development of the focusing optics, the mirror is designed as a single piece. This simplifies the assembly and / or adjustment of the focusing optics.

[0033] A laser machine according to the invention is designed for processing, in particular circumferential welding or circumferential hardening, a workpiece using an annular laser beam. The laser machine comprises a focusing optic as described above and a transport device. The transport device is designed for transporting a plurality, for example 50, 100, 1000 or 10000, of workpieces along a rectilinear, in particular straight or straight, path of movement. The transport device and the focusing optic are arranged relative to each other such that, during movement along the rectilinear path, the workpieces are inserted into the working area of ​​the focusing optic through the first opening by the transport device and removed from the working area of ​​the focusing optic through the second opening.

[0034] The path of movement can be aligned orthogonally to the optical axis of the mirror.

[0035] The transport device can be designed as a conveyor belt. The transport device can be designed to transport the workpieces, specifically only along a straight path. The transport device can be designed to transport the workpieces by means of a continuous movement along the straight path.

[0036] The transport device and / or the focusing optics cannot move during workpiece processing in a way that changes the arrangement of the focusing optics relative to the transport device. In other words, the arrangement of the focusing optics relative to the transport device can remain unchanged during workpiece processing.

[0037] The laser machine can include a laser beam source for generating a laser beam. The focusing optics can be designed to shape the laser beam from the laser beam source into the ring-shaped laser beam.

[0038] A method according to the invention serves for processing, in particular circumferential welding or circumferential hardening, a plurality of workpieces using a previously described focusing optic or a previously described laser machine. The method comprises: transporting the plurality of workpieces along a straight path. During transport, the plurality of workpieces are successively inserted into the working area of ​​the focusing optic, irradiated by the ring-shaped laser beam, and removed from the working area of ​​the focusing optic. This reduces the processing time of the workpieces.

[0039] In particular, the insertion of workpieces into and removal of workpieces from the workspace can be accomplished by transport. This transport can be continuous, and the speed at which the workpieces are transported can be constant.

[0040] In a further development of the process, the laser beam power ranges from 5 kW (kilowatts) to 20 kW, particularly from 5 kW to 10 kW. With such power, any workpiece can be processed quickly. In particular, this power enables transport at relatively high speeds while simultaneously ensuring reliable processing of the workpieces.

[0041] In a further development of the process, the laser beam is continuously directed at the mirror and / or the work area during workpiece transport. This simplifies the process. In particular, it eliminates the need to time the laser beam's switching on and off in relation to the workpiece transport speed.

[0042] In a further development of the method, the numerous workpieces are transported such that each workpiece is irradiated with the ring-shaped laser beam for a specific duration. In other words, the transport speed of the workpieces is selected such that each workpiece is irradiated with the ring-shaped laser beam for the required duration. The irradiation duration ranges from 0.2 ms (milliseconds) to 500 ms, particularly from 0.5 ms to 50 ms, and preferably from 1 ms to 20 ms. Such irradiation durations can be particularly suitable for mass production.

[0043] The irradiation time can specify the duration for which the workpiece is irradiated with the laser beam.

[0044] Further advantages and advantageous embodiments of the invention can be seen from the figures, their description, and the claims. All features disclosed in the figures, their description, and the claims can be essential to the invention, both individually and in any combination. The figures show: Fig. 1. A schematic representation of a laser machine with a focusing optic during the processing of workpieces, Fig. 2 a schematic representation of the focusing optics, wherein a housing of the focusing optics is shown in section, Fig. 3 a detailed view of area III of Fig. 2, Fig. 4 a schematic oblique view of a mirror of the focusing optics, Fig. 5 a schematic top view of the mirror of the focusing optics, and Fig. 6 a detailed view of area VI of Fig. 5.

[0045] Fig. Figure 1 shows a laser machine 500 with a focusing optic 10 during the circumferential welding of a large number of workpieces 12. For the sake of clarity, in Fig. 1 only five workpieces 12 are shown.

[0046] The laser machine 500 has a transport device 502 by means of which the workpieces 12 are transported. The transport device 502 has a conveyor belt. The workpieces 12 can only be transported by the transport device 502 in a straight-line direction of movement 14. Therefore, the workpieces 12 can only be transported along a straight path of movement by the transport device 502. The path of movement and the direction of movement 14 are parallel to each other.

[0047] The workpieces 12 are identical in construction. Each workpiece 12 is cylindrical. Each workpiece 12 is made of plastic. Each workpiece 12 is formed from a first part and a second part, which are welded together using the laser machine 500. The first part and the second part are inserted into one another, thus forming an overlap joint. The overlap joint is irradiated section by section around its circumference with an annular laser beam, creating a circumferential weld seam that welds the two parts together. Due to the irradiation of the workpiece 12 with an annular laser beam, the welding of the two parts together can be described as circumferential welding. Circumferential welding is a laser transmission welding process.

[0048] To produce the circumferential welds, the workpieces 12 are transported by means of the transport device 502. The transport device 502 and the focusing optics 10 are arranged relative to each other such that the workpieces 12 are guided through the focusing optics 10 during movement in the direction of movement 14. The focusing optics 10 and the transport device 502 do not change their relative arrangement to each other during the production of the circumferential welds.

[0049] The laser machine 500 has a laser beam source 16 for generating a laser beam 18. The laser beam 18 is a continuous laser beam. In other words, the laser beam 18 is not pulsed. The laser beam 18 has a power level in the range of 5 kW to 20 kW, particularly 5 kW to 10 kW. The laser beam 18 is continuously supplied to the focusing optics 10 during the transport of the workpieces 12, particularly during the production of the weld seams.

[0050] The focusing optics 10 has a housing 20. The housing 20 is hollow and cylindrical. The housing 20 is elongated and extends along a longitudinal axis 22. The housing 20 is arranged relative to the transport device 502 such that the longitudinal axis 22 and the direction of movement 14 are orthogonal to each other.

[0051] Each of the cylindrical workpieces 12 is elongated and extends along a longitudinal axis 24 of the workpiece 12. The transport device 502 is designed to transport the workpieces 12 in such a way that the longitudinal axes 24 of the workpieces 12 are aligned parallel to the longitudinal axis 22 of the housing 20 during transport.

[0052] The housing 20 has a laser beam opening 28 at a first free end 26 for shining the laser beam 18 into the focusing optics 10.

[0053] In Fig. Figure 2 shows the housing 20 of the focusing optics 10 partially cut away for better illustration of the focusing optics 10.

[0054] The focusing optics 10 have a working area 30. The working area 30 is partially enclosed by the housing 20. The workpieces 12 are inserted sequentially into the working area 30 by means of the transport device 502. When a workpiece 12 is inserted into the working area 30, the laser beam 18 strikes the workpiece 12. In other words, the working area 30 can be defined by the fact that a workpiece 12 can be irradiated with the laser beam 18.

[0055] The focusing optics 10 have a first axicon 32 and a second axicon 34. The two axicons 32 and 34 are arranged concentrically. The laser beam 18 passes through the first axicon 32 and then through the second axicon 34. The two axicons 32 and 34 serve to shape the laser beam 18. After passing through the two axicons 32 and 34, the laser beam 18 has a ring-shaped form.

[0056] The focusing optics 10 has a mirror 38. The ring-shaped laser beam 18 strikes the mirror 38 after passing through the two axicons 32, 34. The mirror 38 has an optical axis 40. The mirror 38 is arranged in the housing 20 such that the optical axis 40 of the mirror 38 is coincident with the longitudinal axis 22 of the housing 20.

[0057] The mirror 38 is arranged at a second free end 42 of the housing 20. The first free end 26 and the second free end 42 are opposite free ends of the housing 20. The housing 20 has a workpiece opening 44 at its second free end 42 for moving the workpiece towards or away from the working area 30.

[0058] The mirror 38 serves to deflect the annular laser beam 18 radially inwards, thereby directing the annular laser beam 18 onto the workpiece 12 when the workpiece 12 is positioned in the working space 30 and the longitudinal axis 24 of the workpiece 12 is aligned with the optical axis 40 of the mirror 38. The mirror 38 is designed for deflecting the annular laser beam 18 such that the laser beam 18 creates an annular spot on the workpiece 12. The circumferential weld seam is formed by this annular spot.

[0059] Fig. 3 shows an area III of Fig. 2 in detail. In Fig. Figure 3 shows the annular spot 39 on the workpiece 12 as a dashed line. The focusing optics 10 has a first recess 46 and a second recess 48. The first recess 46 and the second recess 48 are designed as two separate or independent recesses. The first recess 46 serves, in particular only, for inserting the workpiece into the focusing optics 10, especially into the working space 30, and the second recess 48 serves, in particular only, for removing the workpiece from the focusing optics 10, especially from the working space 30. The working space 30 is arranged between the first recess 46 and the second recess 48.

[0060] The first recess 46 and the second recess 48 are each groove-shaped. Each recess 46, 48 extends through the housing 20 and through the mirror 38. However, it is also conceivable that only the mirror 38 has the two recesses 46, 48.

[0061] The first recess 46 and the second recess 48 are arranged relative to each other such that an imaginary straight line extending from the first recess 46 to the second recess 48 and oriented orthogonally to the optical axis 40 of the mirror 38 intersects the optical axis 40 of the mirror 38. This allows the workpieces 12 to be inserted into the working space 30 through the first recess 46 and removed from the working space 30 through the second recess 48 with a single, in particular, straight movement along the direction of movement 14.

[0062] The first recess 46 and the second recess 48 adjoin the workpiece opening 44. Thus, the first recess 46, the second recess 48, and the workpiece opening 44 form a continuous opening, which is arranged section by section at the second free end 42.

[0063] The transport device 502 and the focusing optics 10 are arranged relative to each other in such a way that the workpieces 12 are successively guided through the first recess 46 by means of the transport device 502 during movement along the straight path of motion, inserted into the working space 30 and removed from the focusing optics 10 through the second recess 48.

[0064] The laser beam 18 is continuously directed at the mirror 38 during the transport of the workpieces 12 through the focusing optics 10 by means of the transport device 502. This ensures that each workpiece 12 is irradiated with the laser beam 18 as it passes through the working area 30. The irradiation duration for each workpiece 12 depends on the transport speed at which the workpieces 12 are transported by the transport device 502. The transport speed is selected such that the irradiation duration is in the range of 0.2 ms to 500 ms, in particular 0.5 ms to 50 ms, preferably 1 ms to 20 ms. The transport device 502 transports the workpieces 12 continuously, in particular at a constant transport speed, through the focusing optics 10.

[0065] Fig. Figure 4 shows the mirror 38. The ratio of the mirror's outer diameter to the outer diameter of one of the workpieces 12 can range from 3:1 to 10:1. In other words, the mirror's outer diameter can be three to ten times the outer diameter of one of the workpieces 12. For example, the ratio of the mirror's outer diameter to the outer diameter of one of the workpieces 12 can be 5:1. The mirror 38 has an outer diameter ranging from 75 mm (millimeters) to 85 mm.

[0066] The mirror 38 is designed to shape the laser beam 18 such that the laser beam 18 continuously illuminates a lateral surface of a workpiece 12 in a ring shape when the workpiece 12 is arranged in the working space 30 and the longitudinal axis 24 of the workpiece 12 is aligned with the optical axis 40 of the mirror 38. In other words, the mirror 38 is designed to shape the laser beam 18 such that the laser beam 18 strikes a workpiece 12, in particular its lateral surface, all the way around when the workpiece 12 is arranged in the working space 30 and its longitudinal axis 24 is aligned with the optical axis 40 of the mirror 38.

[0067] The mirror 38 is ring-shaped. The mirror 38 has a first mirror surface 50 and a second mirror surface 52. The first mirror surface 50 and the second mirror surface 52 are each designed to reflect light with a reflectance of over 98%, preferably 99%, for a wavelength of the laser beam 18. The reflectance of the mirror surface is at most 100% for the wavelength of the laser beam 18.

[0068] The first mirror surface 50 and the second mirror surface 52 are arranged opposite each other. The first mirror surface 50 and the second mirror surface 52 are separated from each other by the first recess 46 and the second recess 48; in particular, the two recesses 46, 48 are arranged between the two mirror surfaces 50, 52. Therefore, the two mirror surfaces 50, 52 do not abut each other.

[0069] Fig. Figure 5 shows mirror 38 in a top view. Fig. Figure 5 shows the extent of the first mirror surface 50 and the second mirror surface 52.

[0070] The first mirror surface 50 and the second mirror surface 52 each have a first region 54, a second region 56, and a third region 58. On each mirror surface 50, 52, the second region 56 is located between the first region 54 and the third region 58. On each mirror surface 50, 52, the first region 54 is located between the first recess 46 and the second region 56. On each mirror surface 50, 52, the third region 58 is located between the second recess 48 and the second region 56.

[0071] Since the mirror 38 cannot reflect the laser beam 18 in the area of ​​the first recess 46 and in the area of ​​the second recess 48, and therefore cannot direct a portion of the laser beam 18 onto the workpiece 12, the first area 54 and the third area 58 of each mirror surface 50, 52 are stepped. This stepped design of the first area 54 and the third area 58 ensures that the laser beam 18 generates the ring-shaped spot on the workpiece 12. In other words, the first area 54 and the third area 58 are stepped such that the two mirror surfaces 50, 52 each direct the laser beam 18 onto the workpiece 12 at an angle of 180°, illuminating its outer surface.This causes the laser beam 18 to create the ring-shaped spot on the workpiece 12 when the workpiece 12 is arranged in the working space 30 and the longitudinal axis 24 of the workpiece 12 is aligned with the optical axis 40 of the mirror 38.

[0072] The stepped first areas 54 and the stepped third areas 58 can each be formed by a facet cut.

[0073] Fig. 6 shows an area VI of Fig. 5 in detail. Fig. Figure 6 shows the third area 58 of the first mirror surface 50. The remaining stepped areas 54, 58 are identically designed, therefore the description for the third area 58 of the first mirror surface 50 applies accordingly to the remaining stepped areas 54, 58.

[0074] The in Fig.The third area 58 shown in Figure 6 is formed by three sub-areas 60. It is also conceivable that the third area 58 is formed by more or fewer sub-areas 60. The sub-areas 60 have a greater distance to the optical axis 40 of the mirror 38 as their distance to the second recess 48 decreases.

[0075] Due to the three partial surfaces 60, the mirror 38 has four edges 62, which separate the partial surfaces 60 from each other, the third area 58 from the second area 56, and the third area 58 from the second recess 48. Each edge 62 has a straight course. Each edge 62 has a course which, if imaginarily extended, intersects the optical axis 40 of the mirror 38.

Claims

[1] Focusing optics (10) for processing, in particular circumferential welding or circumferential hardening, a workpiece (12) by means of an annular laser beam (18), comprising: - a housing (20) that partially surrounds a working space (30) of the focusing optics (10), - a mirror (38) for deflecting the ring-shaped laser beam (18) radially inwards onto the workpiece (12) when the workpiece (12) is arranged in the working space (30) and a longitudinal axis (24) of the workpiece (12) is aligned collinearly with an optical axis (40) of the mirror (38), - a first recess (46) for inserting the workpiece (12) into the work space (30), and - a second recess (48) for removing the workpiece (12) from the work area (30). [2] Focusing optics (10) according to claim 1, - wherein the first recess (46) and the second recess (48) are formed as two separate recesses. [3] Focusing optics (10) according to any one of the preceding claims, - wherein the first recess (46) and the second recess (48) are arranged such that the workpiece (12) can be inserted into the working space (30) by means of a, in particular a single, straight movement through the first recess (46) and can be removed from the working space (30) through the second recess (48). [4] Focusing optics (10) according to any one of the preceding claims, - wherein the mirror (38) has a first mirror surface (50) and a second mirror surface (52), - wherein the first mirror surface (50) and the second mirror surface (52) are separated from each other by the first recess (46) and by the second recess (48). [5] Focusing optics (10) according to claim 4, - wherein the first mirror surface (50) borders the first recess (46) and the second recess (48), - wherein the second mirror surface (52) borders the first recess (46) and the second recess (48). [6] Focusing optics (10) according to claim 4 or 5, - wherein each mirror surface (50, 52) has a first area (54), a second area (56) and a third area (58), - wherein, in each mirror surface (50, 52), the second area (56) is arranged between the first area (54) and the third area (58), - wherein the first area (54) and the third area (58) of each mirror surface (50, 52) are stepped. [7] Focusing optics (10) according to any one of the preceding claims, - wherein the mirror (38) is formed in one piece. [8] Laser machine (500) for processing, in particular circumferential welding or circumferential hardening, a workpiece (12) by means of an annular laser beam (18), comprising: - a focusing optic (10) according to any of the preceding claims, and - a transport device (502) for transporting a large number of workpieces (12) along a straight path of movement, - wherein the transport device (502) and the focusing optics (10) are arranged relative to each other such that the workpieces (12) are inserted into the working space of the focusing optics (10) through the first recess (46) by means of the transport device (502) during movement along the straight path of motion and are removed from the working space (30) of the focusing optics (10) through the second recess (48). [9] Method for processing, in particular circumferential welding or circumferential hardening, a plurality of workpieces (12) by means of a focusing optic (10) according to any one of claims 1 to 7 above or by means of a laser machine (500) according to claim 8, wherein the method comprises: - Transporting the large number of workpieces (12) along a straight path of movement, - wherein the multitude of workpieces (12) are successively inserted into the working space (30) of the focusing optics (10) during transport, irradiated by the ring-shaped laser beam (18) and removed from the working space (30) of the focusing optics (10). [10] Method according to claim 9, - wherein the power of the laser beam (18) is in the range of 5 kW to 20 kW, in particular 5 kW to 10 kW. [11] Method according to claim 9 or 10, - wherein the laser beam (18) is continuously directed towards the mirror (38) and / or the work area (30) during the transport of the workpieces (12). [12] Method according to any one of claims 9 to 11 above, - wherein the transport of the multitude of workpieces (12) is carried out in such a way that each workpiece (12) is irradiated with the ring-shaped laser beam (18) for an irradiation period, - wherein the irradiation duration is in the range of 0.2 ms to 500 ms, in particular 0.5 ms to 20 ms.

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