Optical module with device for automatically changing a collimation optic

Abstract

Optical module (2) for a machine (1) for processing workpieces and / or for producing shaped bodies by selectively solidifying material powder into contiguous areas using a laser beam, comprising: a housing (8) with means for detachably attaching the optical module (2) to the machine (1) and a collimation lens changer (3) detachably arranged in the housing (8) with at least two collimation lenses (4) movable into a beam path of the laser beam for collimating the laser beam, wherein the collimation lens changer (3) is designed as a turret and is rotatably mounted in the housing via a vertical axis of rotation (5), and the collimation lens changer (3) comprises: a case; a mechanism for automatically changing the collimation lenses (4); a plurality of cooling channels (3a) in the housing of the collimation lens changer (3), through which a fluid coolant flows to cool the collimation lenses (4); and Means for measuring the temperature of the collimation lenses (4), wherein a first axial cooling channel as a supply for the fluid coolant and a second axial cooling channel as a return for the fluid coolant pass through the axis of rotation (5), and wherein the axial cooling channels are connected to cooling channels (3b) extending radially outwards in a first plane through the housing of the collimation lens changer (3), wherein further radial cooling channels run through the collimation lens changer (3) in a second plane parallel to the first plane, and wherein the radial cooling channels (3a) of the two planes are in flow communication with each other via cooling channels running perpendicular to the first and second planes through the housing of the collimation lens changer (3) in order to enable the coolant circulation.

Description

[0001] The present invention relates to an optical module for a machine for processing workpieces and / or for producing shaped bodies by selectively solidifying material powder into contiguous areas using a laser beam. The invention relates in particular to an optical module for a machine for producing shaped bodies according to the principle of selective laser melting, selective laser sintering, or laser cladding. In particular, material powders made of metal, plastic, or ceramic can be used. Furthermore, the optical module according to the invention can, for example, also be used in a machine for laser welding or laser cutting. The term "laser machine tool" or simply "machine" is used below to refer collectively to the various types of machines for processing / manufacturing / producing a workpiece or a shaped body with a laser beam.

[0002] Using selective laser melting, laser sintering, or laser cladding, shaped objects such as machine parts, tools, prostheses, jewelry, etc., can be manufactured or processed according to geometric description data of the respective shaped objects, for example, by layer-by-layer construction from a metallic or ceramic material powder or a plastic powder. In the manufacturing process, the material powder is heated by a focused laser beam in a predefined area corresponding to a selected cross-sectional region of the shaped object model, so that the material powder is melted in the irradiated areas to form cohesive, solidified sections. A protective gas can prevent oxidation during the build-up process. After cooling, a material layer is formed that can be mechanically processed.

[0003] For the state of the art in the field of selective laser melting, reference is made, for example, to DE 10 2015 222 689 A1. Furthermore, a laser machine tool of the type mentioned above is known, for example, from EP 2 052 845 A2. A machine tool for cladding is described, for example, in German patent application DE 10 2013 224 649 A1. German patent application DE 196 30 147 A1 describes a connection head for processing a workpiece using a laser beam, which has an automatic focusing lens changing mechanism designed as a turret.

[0004] The article “Laser Unit Makes Cladding Possible on Machining Centers” by Nowotny et al. in “MM Das Industriemagazin”, 17 / 2009, page 42 ff., describes a laser processing optic that is inserted into the milling spindle of a CNC machine via a steep taper. Welding material (material powder) is fed into the laser focal point through a powder nozzle. The workpiece can then be milled in the same machine.

[0005] Patent application US 2017 / 0136578A1 describes a machine for the layer-by-layer construction of a three-dimensional shaped body by melting a material powder. The material powder is guided to a working point by means of a powder nozzle attached to a laser processing head, where it is melted by a laser beam passing through the powder nozzle. The machine includes a powder nozzle exchange unit that replaces the powder nozzle attached to the laser processing head.

[0006] European patent application EP 2 062 679 A1 discloses a processing head for a laser processing machine, comprising a stationary part in the form of a laterally open housing that encloses a space for an interchangeable module. This module can be separated as a whole from the stationary part of the processing head without having to disassemble the stationary part into individual components. The interchangeable module includes a focusing optic that is movable coaxially to the laser beam and a measuring device for determining the position of the focusing optic.

[0007] German patent DE 10 2014 209 308 A1 discloses a laser processing head with a lens exchange system comprising two lenses of different focal lengths. The lens exchange system allows one of the lenses to be positioned within the beam path of a laser beam in the laser processing head. The lenses are held on a common frame that is pivotable about a rotational axis. This axis of rotation is perpendicular to a direction of one of the laser beam axes. The optical axes of the two lenses intersect at a point of intersection. The axis of rotation is perpendicular to a plane of rotation that contains the optical axes of the two lenses. The respective distances of the optical axes of the two lenses to the axis of rotation in the plane of rotation are equal.

[0008] US Patent 2014 / 0072003A1 discloses a laser processing machine with a plurality of collimating lenses for converting a laser beam from a laser oscillator, exiting an optical transmission fiber, into parallel light beams. A condenser lens further serves to collimate the laser beam, which is then emitted onto a workpiece. A nozzle is positioned on the side of the workpiece opposite the condenser lens. The distance from the exit point to the nozzle tip remains constant. The collimating lenses are spaced apart in a direction parallel to an optical axis. A switching device toggles the position of each collimating lens in the orthogonal direction, allowing the center of one of the collimating lenses to be aligned with the center of the laser beam. The collimating lenses each have a different focal length.

[0009] Other laser processing machines of this type are described, for example, in DE 10 2008 048 323 B3, DE 10 2009 046 485 A1, DE 20 2009 012 942 U1 and EP 2 399 703 A1.

[0010] A laser machine tool is typically operated with a laser that provides a laser beam with an output power of several hundred to several thousand watts, usually operating in continuous wave (CW) mode. The energy transfer from the laser beam to the material powder is particularly crucial for the machining process. This transfer is influenced both by the absorption capacity of the material powder and by the intensity of the laser beam. Therefore, in addition to the absolute laser power, the beam diameter determines the melting process. The beam diameter of the laser beam is typically determined by the focal length of a focusing lens and by the beam diameter of the collimated laser beam in front of the focusing lens. The beam diameter of the collimated laser beam can be specifically determined by the focal length of a collimating lens.Thus, the beam diameter of the focused laser beam, or the waist of a Gaussian laser beam, can be adjusted by appropriately selecting the collimating lens, without changing the focal length of the focusing lens.

[0011] According to the prior art, essentially two types of machines for processing workpieces and / or producing shaped parts by selectively solidifying material powder into contiguous areas using a laser beam, in particular by selective laser melting or selective laser sintering, are known. The machine types differ, among other things, in the way the material powder is supplied. In a first machine type, a powder bed is built up layer by layer. In a second machine type, the material powder is supplied at the processing location by means of a powder nozzle. The present invention relates in particular to machines in which the laser beam is supplied by means of a laser processing head.The mechanical setup for moving the laser processing head and / or the workpiece can be similar to that of a conventional five-axis machining center, except that the laser processing head replaces a mechanical tool. For several years now, machine tools have also been available that allow both laser processing and machining, for example with a milling tool. In such hybrid machining centers, the laser processing head can be attached to the tool spindle mount.

[0012] The laser processing head can include a variety of optical components for manipulating the laser beam, such as collimating, focusing, deflecting, monitoring, switching, and / or modulating the laser beam's power. It has proven advantageous to combine as many optical components as possible into a pre-assembled, replaceable optical module that can be detachably attached to the machine using suitable means. This simplifies and accelerates the maintenance of a laser machine tool, allowing for more efficient machine operation by reducing downtime.

[0013] The present invention is based on the objective of providing an optical module that can be replaced quickly and easily, and that allows the intensity of a laser beam to be adjusted according to the respective requirements for processing a workpiece or producing a shaped body.

[0014] The problem is solved by an optical module for a machine for processing workpieces and / or for producing shaped bodies by selectively solidifying material powder into contiguous areas using a laser beam according to claim 1.

[0015] In particular, the collimation lens can be automatically changed during a processing operation, allowing the diameter of the laser beam at the working point, and consequently the intensity of the laser beam at the working point, to be automatically adjusted during the processing operation. Because the collimation lens changer has a mechanism for automatically changing the collimation lens, the lens change can be integrated into the processing operation without requiring any manual steps. The working point of the laser beam typically corresponds to the focal point of the focused laser beam.

[0016] The collimating lens is used to collimate a laser beam coupled divergently into the optical module. For example, the laser beam can be coupled into the optical module via an optical fiber. The optical module can therefore include means for connecting an optical fiber, in particular a fiber coupler. Since an optical fiber can transmit laser light over many meters, it is possible to place the laser in a protected location away from the process chamber. The distance between the collimating lens and the end of the optical fiber corresponds approximately to the focal length of the collimating lens. The collimated laser beam can be focused to a focal point by a focusing lens attached to the optical module. The laser beam thus exits the optical module as a focused beam.

[0017] Optical components of laser machine tools can be subject to increased wear due to the relatively high laser power. Furthermore, especially in hybrid machines capable of both laser processing and machining, optical components can become contaminated by coolant, dust, chips, and other particles. Material powder can also contribute to contamination. Dirt particles deposited on an optical component can lead to significant heat buildup, particularly at high laser powers, and thus damage the component. Therefore, it is desirable for optical components to be replaceable quickly and easily in case of damage or contamination. This is achieved, in part, by allowing the entire optical module to be detachably mounted as a pre-assembled unit on an actuator axis, thus facilitating easy replacement.On the other hand, interchangeable optical components allow for quick changes without removing the entire optical module. For example, the collimation lens changer enables a quick, automatic change of the collimation lens without requiring the replacement of the entire collimation changer or optical module.

[0018] The optical components arranged in the optical module can each be detachably mounted in or on the housing of the optical module. This allows for automatic replacement of the optical components during machine operation. Conversely, an optical module requiring maintenance can be restored to operational condition by replacing individual optical components. For example, the collimation changer can be detachably mounted within the housing of the optical module as a replaceable module and thus be exchanged during maintenance of the optical module.

[0019] Advantageous training and further education programs, which can be used individually or in combination, are the subject of dependent claims.

[0020] The collimation lens changer comprises a turret that can accommodate a plurality of collimation lenses. The collimation lenses can be arranged around a common driven axis of rotation of the turret, enabling automatic lens exchange by rotating the turret. The drive of the collimation lens changer causes the collimation lenses to rotate around the common axis of rotation of the turret. This advantageously allows for the realization of a compact collimation lens changer with a plurality of collimation lenses. In particular, the collimation lenses are arranged such that their axis of symmetry is aligned parallel to the driven axis of rotation of the turret. Furthermore, the collimation lenses are positioned along the direction of the laser beam according to their focal length, so that they collimate a diverging laser beam.In particular, the appropriate distance between the collimating lens and a fiber coupler corresponds approximately to the focal length of the collimating lens.

[0021] As an alternative to a turret, the collimation lens changer, in an embodiment not covered by the claims, can have a sliding system with driven carriages, wherein the collimation lenses are arranged in parallel planes according to their focal length and can be moved into or out of the laser beam path by sliding. In this way, a compact collimation lens changer with a plurality of collimation lenses can also be realized.

[0022] The collimation lens exchange system incorporates cooling mechanisms for the collimation lenses. Cooling the collimation lenses largely prevents damage to the lenses caused by heat transfer from the laser beam. This cooling process extends the lifespan of the lenses. Furthermore, heating a lens can alter its shape, potentially affecting its focal length. Cooling the lenses mitigates these effects, particularly reducing the thermal lens effect.

[0023] The collimation lens exchange system includes a means for measuring the temperature of the collimation lenses. This temperature measurement can be achieved using a temperature sensor, such as an NTC resistor, which can output a reading to a machine controller. Together with the means for cooling the collimation lenses, the temperature of the collimation lenses can be regulated to a setpoint. Operating the collimation lenses at a predetermined temperature ensures that the influence of temperature on the optical properties of the lenses is kept constant.

[0024] The optical module preferably includes means for attaching an automatically interchangeable focusing lens module. The focusing lens module can be connected to the optical module, for example, via at least two clamping bolts. The optical module can have corresponding receptacles for the clamping bolts. These receptacles can be designed, in particular, as hydraulically or pneumatically actuated clamping mechanisms or spring-loaded clamping mechanisms. The optical module can also include means for monitoring the temperature of the focusing lens or a protective glass for the focusing lens. By providing means for attaching an automatically interchangeable focusing lens module, an automatic change of the focusing lens can be achieved. This lens can then be exchanged fully automatically during the manufacturing or machining process, similar to a tool in a machining center.The automated switching of the focusing and collimating lenses allows the laser beam diameter at the focus to be adjusted within a wide range, depending on the requirements. The clamping bolts enable quick and secure attachment of the focusing lens module to the optical module. Furthermore, the clamping bolts ensure that the focusing lens module can be attached to the optical module with high positional accuracy.

[0025] A focusing lens module preferably comprises a substantially cylindrical carrier with a circular cross-section, made, for example, of a metal or a metal alloy. A focusing lens is arranged in the carrier. Preferably, the focusing lens can be detachably mounted in the carrier of the focusing lens module, so that the focusing lens can be replaced. The focal length of the focusing lens can be, for example, several hundred millimeters. The focusing lens can be a conventional converging lens. The focusing lens module preferably includes means for measuring the temperature of the focusing lens. It is further preferred that the focusing lens module includes means for cooling the focusing lens.

[0026] The focusing lens module can include at least one protective glass to protect the focusing lens from contamination. The protective glass can also protect the focusing lens from mechanical impacts. The protective glass is preferably detachably mounted in the carrier of the focusing lens module. If contaminated, the protective glass can be replaced. Preferably, a protective glass is arranged axially on both sides of the focusing lens within the carrier of the focusing lens module, so that the focusing lens is protected from contamination on both sides. The focusing lens module can also include means for measuring the temperature of the at least one protective glass. Thus, contamination of a protective glass can be detected, for example, by a temperature increase.

[0027] The optical module may also include means for attaching an automatically interchangeable powder nozzle. The powder nozzle can be connected to the optical module, for example, via at least two clamping bolts. For this purpose, the optical module may have corresponding receptacles for the clamping bolts. These receptacles may incorporate a clamping mechanism, which may be hydraulically or pneumatically actuated, or spring-loaded. The clamping bolts allow for quick and secure attachment of the powder nozzle to the optical module. Furthermore, the clamping bolts ensure that the powder nozzle can be attached to the optical module with high positional accuracy.

[0028] The powder nozzle has at least one channel for material powder to convey the powder to the laser's focal point. Preferably, the powder nozzle has at least two, three, or four material powder channels to guide the material powder through the nozzle as uniformly and coaxially as possible with the laser beam. The material powder channels can also be used to supply a shielding or carrier gas. The shielding gas serves to prevent a reaction between the heated material powder and atmospheric oxygen. Furthermore, the shielding gas can act as a carrier gas to transport the material powder. The material powder is then carried along by the flow of the carrier gas and transported through the material powder channels to the operating point. Inert gases such as argon are particularly suitable as shielding or carrier gases.The more material powder channels are provided in the powder nozzle, the higher the flow rate of the material powder can be. To guide the material powder as evenly as possible to the focal point of the laser beam, a configuration with at least three or four material powder channels has proven advantageous. Optionally, the powder nozzle can have a variety of different material powder channels with varying diameters for different powder particle sizes.

[0029] The optical module can include a variety of interfaces to guide material powder from the material powder channels located on the optical module into the material powder channels of the powder nozzle. These interfaces can, for example, be designed as inlet openings on a flange for attaching the powder nozzle. The inlet openings can include sealing elements for a gas-tight seal when the powder nozzle is attached to the optical module. The inlet openings can also include means for aligning them with the channels on the optical module.

[0030] The powder nozzle can have cooling channels for a fluid coolant to cool the nozzle. The optical module can have corresponding lines to supply the coolant to the powder nozzle. Preferably, the optical module has at least one coolant supply line and one coolant return line. The powder nozzle preferably has at least two couplings as detachable interfaces between the coolant supply and return lines of the optical module and the coolant channels of the powder nozzle. The couplings can, for example, be designed as quick-release couplings that can be connected to corresponding counterparts on the optical module.

[0031] By providing means for the detachable fastening of an automatically interchangeable powder nozzle, an automatic change of the powder nozzle can be achieved. This nozzle can then be exchanged fully automatically during the manufacturing or machining process, similar to a tool in a machining center.

[0032] The optical module can also include a camera for monitoring the processing. The camera's viewing direction can be superimposed on the laser beam path, for example, using a dichroic mirror, so that the camera can view the working point along the laser beam and monitor the process. The dichroic mirror can be cooled and its temperature monitored.

[0033] The beam path through the optical module is preferably sealed gas-tight to maintain a protective gas atmosphere. Inert gases such as nitrogen or argon can be used as the protective gas. Preferably, the entire housing of the optical module is sealed gas-tight. The use of a protective gas can slow down wear of the optical components located within the optical module. To establish the protective gas atmosphere within the housing of the optical module, the optical module preferably has corresponding gas supply lines. Instead of sealing the housing gas-tight, the housing can also be designed to allow for the creation of overpressure by supplying the protective gas, thus preventing, for example, dust or material powder particles from entering the interior of the optical module.

[0034] A preferred optical module includes means for connecting feeds for a process gas. The process gas can, for example, be a protective gas that prevents oxidation of the workpiece by reaction with atmospheric oxygen. The process gas can also serve as a carrier gas for conveying the material powder. The optical module preferably includes lines for the process gas to guide it via suitable interfaces with channels in a powder nozzle to the focal point of the laser beam (operating point). Suitable process gases include, for example, argon or nitrogen. In particular, the process gas is guided to the operating point via the powder nozzle.

[0035] Preferably, each collimating lens has at least one protective glass to protect it from contamination. The protective glass is positioned in the beam path before and / or after the collimating lens. To prevent disruptive reflections back into the laser, the protective glass can have an anti-reflective coating and / or be positioned at a slight angle to the beam direction. If the protective glass becomes contaminated or damaged, it can be removed and replaced. This allows the collimating lenses to be effectively and easily protected from contamination and damage.

[0036] In a preferred embodiment of the optical module, the collimation lens changer comprises at least three, more preferably at least four or at least five collimation lenses. The more collimation lenses are arranged in the collimation changer, the more different focal lengths can be provided, thus enabling a wider range of beam diameters. In addition to collimation lenses with different focal lengths, several identical collimation lenses can also be provided, allowing for replacement with a ready-to-use collimation lens if a collimation lens or protective glass becomes dirty or damaged, without requiring manual maintenance of the optical module. This increases the versatility of the machine while simultaneously reducing the need for maintenance. Brief description of the characters

[0037] Further advantageous embodiments are described in more detail below with reference to an exemplary embodiment shown in the drawings, to which, however, the invention is not limited.

[0038] They show schematically: Fig. 1: a machine tool with an optical module for manufacturing or processing a shaped body or workpiece using laser radiation. Fig. 2: a perspective sectional view of an embodiment of an optical module according to the invention. Fig. 3: another perspective sectional view of the in Fig. 2 shown embodiment of the optical module according to the invention. Fig. 4: a perspective sectional view of an upper area of ​​the optical module according to the invention as described in the exemplary embodiment. Fig. 5: a longitudinal section of the collimation lens changer according to the invention. Fig.6: a cross-section of the collimation lens changer according to the invention. Fig. 7: A perspective view of an embodiment of a machine tool for manufacturing or machining a shaped body or workpiece using laser radiation. Fig. 8: A perspective view of a tool changer for a machine tool for manufacturing or machining a shaped body or workpiece using laser radiation. Fig. 9: (A) a partially cutaway perspective view and (B) a perspective view of an interchangeable powder nozzle. Fig. 10 An illustration of the operating principle of laser cladding. Fig. 11 (A) a perspective view of an interchangeable focusing lens module, (B) and (C) sectional views of the interchangeable focusing lens module with different focal lengths of the focusing lens. Detailed description of the invention using an exemplary embodiment

[0039] In the following description of a preferred embodiment of the present invention, the same reference numerals denote identical or comparable components.

[0040] Fig.Figure 1 shows a schematic representation of a machine 1 for processing a workpiece 20 and / or for producing a shaped body 20 by selectively solidifying material powder into contiguous areas using laser radiation. The machine 1 has a machine frame 21 to which a workpiece table 20 and an optical module 2 according to the invention are attached indirectly via intermediate positioning axes 18, 19. The positioning axes 18, 19 can each have several translational (X, Y, Z) or rotational (φ, λ, θ) axes, which are adjustable according to a machine control. The design can be such, for example, that the optical module 2 is attached to the machine frame 21 via one, two, or three translational positioning axes 18 (X and / or Y and / or Z), while the workpiece table 20 is attached to the machine frame 21 via one, two, or three rotational positioning axes 19.Such a laser machine tool 1 typically has a (not shown) enclosed cabin in which, for example, a protective gas atmosphere can be created, and which shields the working area from contamination.

[0041] A workpiece can be detachably attached to the workpiece table 20 for machining. Alternatively, a shaped body can be built up layer by layer on the workpiece table 20 by selectively solidifying material powder.

[0042] Machine 1, for example, could be a five-axis laser machine tool for producing shaped parts by selectively solidifying material powder into contiguous areas using laser radiation. The optical module 2 is detachably attached to the positioning axes 18, allowing for quick and easy replacement when necessary, for example, for maintenance. In such a five-axis laser machine tool, the optical module 2 is attached to the machine frame 21 via three translational positioning axes 18 (X, Y, and Z), and the workpiece table 20 is arranged on the machine frame via two rotary axes.

[0043] An exemplary representation of a five-axis laser machine tool 1 for producing shaped bodies by selectively solidifying material powder into contiguous areas using laser radiation is shown in Fig. 7 shown. The illustrated embodiment corresponds essentially to the one in Fig.Figure 1 schematically depicts machine 1. The workpiece table 20 and the optical module 2 are arranged in a process chamber 22, which can be sealed gas-tight essentially by a process chamber door 23. A display 24 located outside the process chamber 22 serves as an interface between the user and the machine control. Measured values ​​and / or warning messages and / or control applications can be displayed on this display 24.

[0044] The machine tool 1 includes a tool changer 25, which can be moved laterally into the process chamber 22 by means of positioning axes 25a, 25b. A detailed view of the tool changer 25 is shown in Fig. Figure 8 shows that a variety of focusing lens modules 13 and a variety of powder nozzles 15 can be arranged on the tool changer 25. The tool changer 25 is shown in Figure 8. Fig.The tool changer 25 shown in Figure 8 has three storage positions for powder nozzles 15 with different axial lengths. The tool changer 25 also has a storage area for at least two focusing lens modules 13 with focusing lenses 14 of different focal lengths. The focusing lens modules 13 and the powder nozzles 15 can be moved into the process chamber 22 by means of two positioning axes 25a and 25b, respectively, so that they can be attached to the optical module 2. A method for changing the powder nozzles 15 and the focusing lens modules 13 is described below.

[0045] The tool changer 25 can be moved by means of the positioning axes 25a, 25b into a tool chamber that can be separated from the process chamber 22 by means of a movable partition. In the tool chamber, the focusing lens modules 13 and the powder nozzles 15 are protected from contamination, for example by material powder or welding fumes, when machining of the workpiece is carried out in the process chamber 22.

[0046] Fig.Figure 2 shows an embodiment of an optical module 2 according to the invention, which is detachably mounted on an actuating axis 18. The actuating axis 18 is, for example, a translation axis movable in the Z-direction, which can be arranged on two further translation axes movable in the X- and Y-directions, so that the optical module 2 is movable in all three spatial directions. The optical module 2 is mounted on the actuating axis 18 in such a way that the laser beam exits the optical module 2 perpendicularly downwards (parallel to the direction of gravity, i.e., in the Z-direction). By moving the actuating axes 18, a focus of the focused laser beam can thus be moved in three dimensions in space to process a workpiece or to build up a shaped body layer by layer. Thus, a shaped body can be built up layer by layer, similar to a 3D printer, by fusing material powder.

[0047] The optical module 2 has a housing 8 in which a multitude of optical components are arranged. The housing 8 serves both as a mechanical platform for arranging the optical components and as a means of protecting them from mechanical influences. A protective gas atmosphere can be created within the housing 8. For example, overpressure can prevent the ingress of particles and dirt into the housing.

[0048] A fiber coupler 10 is arranged at the top of the housing 8, through which a laser beam from an optical fiber can be coupled. By using an optical fiber, laser light from a laser beam source can be reliably guided to the optical module 2. The flexible optical fiber allows the optical module 2, and thus the laser beam, to be moved without having to move the laser beam source itself. Furthermore, an optical fiber can deliver a laser beam with a particularly uniform beam profile.

[0049] A high-power solid-state laser can be used as a laser beam source. This includes, for example, doped YAG lasers. In particular, a ytterbium-doped YAG disk laser with a wavelength of 1030 nm can serve as a laser beam source. Alternatively, a neodymium-doped YAG laser with a wavelength of 1064 nm can be used as a beam source. Solid-state lasers can provide laser beams with power levels ranging from a few watts to several thousand watts. This allows for sufficient laser power to be provided for various processing and manufacturing applications.

[0050] Directly below the fiber coupler 10, the collimation lens changer 3 is arranged in the housing 8 of the optical module 2. A collimation lens 4 with a first focal length of, for example, 80 mm is arranged in the collimation lens changer 3 such that the laser beam exiting the fiber is collimated to a diameter of approximately 36 mm. The collimation lens changer 3 can include further collimation lenses 4 with focal lengths of, for example, 50 mm, 60 mm, and / or 100 mm or more. This allows collimated laser beams with diameters between approximately 10 mm and 100 mm to be provided. Suitable types of converging lenses can be used as collimation lenses 4. The material, coating, and other lens properties can be selected depending on the laser wavelength and laser power used.

[0051] The collimated laser beam is directed by two deflecting mirrors 6, 7 arranged in the optical module 2 onto a focusing lens 14, which focuses the laser beam. The position or orientation of the deflecting mirrors 6, 7 is preferably adjustable, so that the beam path of the laser beam can be automatically adjusted. The correct adjustment of the laser beam can be monitored, for example, by the camera 9. In particular, the deflecting mirrors 6, 7 can be adjustable via the machine control system. For this purpose, the deflecting mirrors 6, 7 can each be arranged on adjustable holders that can be controlled by the machine control system via control signals. The optical module 2 can have suitable interfaces for detachably connecting signal lines for the machine control system.

[0052] The focal length of the focusing lens 14 can, for example, be between 50 mm and 500 mm. The focusing lens 14 is preferably arranged in an automatically interchangeable focusing lens module 13, which can be attached to the optical module 2 via a fastening mechanism 11, 16. Thus, by changing the focusing lens module 13, the focal length of the focusing lens 14 can also be changed fully automatically.

[0053] Seven exemplary combinations of lens focal lengths for the collimating lens 4 and the focusing lens 14 are shown in Table 1. Table 1 also lists exemplary resulting values ​​for the diameters of the collimated laser beam and the focused laser beam for a fiber core diameter of 600 µm. The smaller the beam diameter, the higher the laser intensity. A small beam diameter of the focused laser beam results in a high laser beam intensity, so that a melting process generally takes less time, since more energy can be transferred to a smaller area. On the other hand, smaller structures can be produced with a smaller beam diameter at the focal point of the laser beam. A smaller beam diameter at the focal point can be achieved with the same focal length of the focusing lens by using a larger beam diameter of the collimated laser beam in front of the focusing lens.A larger beam diameter of the collimated laser beam has the advantage that the optical elements in optical module 2 are exposed to a lower laser intensity. This reduces the likelihood of damage to the optical elements, as they are, for example, heated less. Table 1: Seven exemplary combinations of collimating lens focal length and focusing lens focal length: Size Unit Example 1 Example 2 Example 3 Example 4 Example 5 Example 8 Example 7 Performance W 4000 4000 4000 4000 4000 4000 4000 Focal length of the collimating lens mm 50 60 80 100 60 80 100 Diameter of the collimated beam mm 5a 25b 36 45 25b 36 45 Focal length of the focusing lens mm 300 300 300 300 200 200 200 Diameter of the focused beam mm 3,6 3 2,3 1,8 2 1,5 1,2

[0054] An exemplary embodiment of the focusing lens module 13 is shown in Fig. 11A to C shown. Fig. Figure 11A shows a perspective view of a focusing lens module 13 with a substantially cylindrical support housing, preferably made of a metal with the lowest possible coefficient of thermal expansion. According to the examples in Table 1, Fig. 11B a focusing lens module 13 with a focusing lens 14 having a focal length of 200 mm, and Fig.11C comprises a focusing lens module 13 with a focusing lens 14 having a focal length of 300 mm. The focusing lenses 14 of different focal lengths are arranged in the various focusing lens modules 13 such that the resulting focal point of the laser is always located at the same position.

[0055] Fastening means, for example two clamping bolts 16, are arranged at an upper edge of the focusing lens module 13. The fastening means 16 also serve to ensure the highest possible positioning accuracy of less than 1 mm. This is particularly important for the precise guidance of the laser beam through the powder nozzle and to the correct operating point. Should deviations nevertheless occur, these can be detected by the camera 9 and corrected by the deflecting mirrors 6, 7. The focusing lens module 13 has at least one protective glass 14a to protect the focusing lens 14 from contamination or damage. Preferably, as shown in the sectional drawings of the Fig. 11B and C show a protective glass 14a arranged on both sides of the focusing lens 14 in the focusing lens module 13 to protect the focusing lens 14 from contamination or mechanical impact from both sides.

[0056] The temperature of at least one protective glass 14a can be monitored by a sensor 13a. Fig. In 11B and C, only the temperature of the upper protective glass 14a, which is first struck by the laser beam, is monitored by a sensor 13a. A temperature-dependent resistor (NTC resistor) or a thermocouple can be used as the sensor. The thermocouple can, in particular, be a wire made of a platinum alloy. Similarly, the temperature of other optical components in the optical module 2, in particular the collimating lenses 4, the protective glasses of the collimating lenses 4, the deflecting mirrors 6, 7, and / or the focusing lens 14, can also be monitored.

[0057] An analog measurement signal generated by the temperature sensor 14a is transmitted via interfaces 13b on the focusing lens module 13 to signal lines in the optical module 2. From there, the measurement signal is output to a machine control unit and converted into a temperature value, so that the temperature of an optical component of the optical module 2 can be displayed in degrees Celsius. The measured temperature values ​​can be shown, for example, on the display 24. A temperature threshold can be stored in the machine control unit for each optical component. If the measured temperature of an optical component exceeds the stored threshold, a warning signal can be generated. The warning signal can be issued, for example, as a warning to a user. The warning can be displayed visually, for example, on the display 24 or by means of a warning light.Additionally or alternatively, the laser can be switched off to prevent damage to the optical component.

[0058] The interfaces 13b can also be used to signal to the machine control system that a focusing lens module 13 has been successfully attached. Similarly, the machine control system can detect that the focusing lens module 13 has been successfully detached and placed down when a signal transmitted via the interfaces 13b is interrupted.

[0059] An interchangeable powder nozzle 15 can be attached below the focusing lens module 13, which can be mounted on the optical module 2. An exemplary embodiment of the powder nozzle 15 is shown in Fig. 9A and Fig.Figure 9B illustrates this. Like the focusing lens module 13, the powder nozzle 15 has fastening means 16 that can be attached to the optical module 2 by means of corresponding receptacles 12. For example, several clamping bolts can be arranged on the powder nozzle 15 as fastening means 16. Such clamping bolts are also used in a similar manner for fastening tools in conventional machine tools. The receptacles 12 on the optical module 2 can clamp these clamping bolts for fastening the powder nozzle 15 via a hydraulic, pneumatic, or spring-loaded mechanism, so that the powder nozzle 15 is detachably attached to the optical module 2, whereby the same position of the powder nozzle 15 can always be achieved within a defined tolerance.

[0060] The in Fig. 2 and Fig.The powder nozzle 15 shown in Figure 9 has a flange 15a at its upper end, facing the optical module 2, on which the fastening means 16, for example two clamping bolts, are arranged. A substantially cylindrical central section of the powder nozzle 15 is arranged on the flange 15a. A substantially conical powder nozzle tip 15b is arranged at the lower end of the central section.

[0061] The flange 15a of the powder nozzle 15 is equipped with connections 15f and 15g, respectively, for supplying a coolant or material powder. The coolant connections 15f can, for example, be designed as quick-release couplings that automatically connect to the corresponding lines on the optical module 2 when the powder nozzle 15 is attached. The material powder inlets 15g can be simple openings with a sealing ring. When the powder nozzle 15 is attached to the optical module 2, the inlets with the sealing rings are pressed against corresponding outlets on the optical module, creating a gas-tight connection.

[0062] The inlets 15g for material powder are each connected to channels 15d for the material powder, which run through the powder nozzle 15 to the tip 15b of the powder nozzle 15. An annular gap 15c is formed in the tip 15b of the powder nozzle 15, the width of which can taper in the direction of flow to create a nozzle effect. The transition between the material powder channels 15d and the annular gap 15c is shaped such that a uniform distribution of the material powder is achieved. The flow of the material powder can therefore have the form of a cone aligned coaxially with the focal point of the laser beam, as illustrated in the figure. Fig. 10 indicated.

[0063] The powder nozzle tip 15b can be detachably attached to the powder nozzle 15, allowing it to be replaced, for example, if damaged or deformed by heat. In a multi-part design of the powder nozzle 15, the powder nozzle tip 15b can also be made of a different, more heat-resistant and / or harder material than the rest of the powder nozzle 15. Differently sized powder nozzle tips 15b can be used, for example, for different laser beam diameters. Accordingly, different powder nozzles 15 with differently sized powder nozzle tips 15b can be kept in the machine 1, so that the entire powder nozzle 15 can be replaced if necessary. The diameter of the lower opening of the powder nozzle tip 15b, facing the workpiece, can be, for example, 1 mm, 2 mm, or 3 to 4 mm.

[0064] The powder nozzle 15 has at least two couplings 15f for coolant, which are preferably designed as quick-release couplings. One coupling 15f serves as a connection for the coolant supply from the optical module 2, the other coupling 15f serves as a connection for the coolant return to the optical module 2. The coolant connections 15f are in flow communication with coolant channels 15e in the powder nozzle 15, which are shown in the partially cutaway view of the Fig. Figure 9A illustrates this. The coolant channels 15e can, for example, be arranged in a ring around the laser beam aperture to ensure uniform cooling of the powder nozzle 15.

[0065] Inside the flange 15a, a substantially cylindrical recess is formed for the focusing lens module 13. When the focusing lens module 13 and the powder nozzle 15 are attached to the optical module 2, the lower end of the focusing lens module 13 is located within the recess in the powder nozzle 15. The focusing lens module 13 and the powder nozzle 15 are thus arranged coaxially with each other and with the laser beam on the optical module 2.

[0066] The powder nozzle 15 has a very complex shape due to the numerous channels for coolant 15e and channels for material powder 15d, as well as its axially tapered opening towards the laser focal point. Such a complex shape can be produced, for example, by a laser cladding process in a machine 1 according to the invention. In order to carry out the manufacturing process of the powder nozzle 15 by laser cladding in the shortest possible time and with the greatest possible material savings, the essentially cylindrical central section of the powder nozzle 15 can, for example, be constructed with the thinnest possible wall thickness. To increase the mechanical strength of the powder nozzle 15, the wall can be reinforced by lamellae 15l. Similarly, the transition between the flange 15a and the central section of the powder nozzle 15 can be manufactured in a material-saving manner, for example, by using a profile as shown in Fig.The honeycomb structure shown in 9B is used, which offers high mechanical strength with low material consumption.

[0067] The flange 15a and the central section of the powder nozzle 15 can, for example, be made of aluminum. The diameter of the flange 15a can be approximately 150 mm to 170 mm, preferably 160 mm. The length of the powder nozzle 15 can be approximately 125 mm to 145 mm, preferably 135 mm. The diameter of the central section of the powder nozzle can be approximately 60 mm to 70 mm, preferably 67 mm. Preferably, the powder nozzle 15 can also be designed to be even more compact in order to reduce the risk of collisions with the workpiece.

[0068] Replacing the powder nozzle 15 can be carried out, for example, as described below. The partition between the process chamber 22 and the tool chamber located to the side of it is slid open. Using the positioning axis 25b, the lower part of the tool changer 25 with the powder nozzles 15 is moved into the process chamber 22. The positioning axes 18 move the optical module 2 to the position where the tool changer 25 with the multiple powder nozzles 15 is located. Unlike in [previous description], to place a powder nozzle 15 attached to the optical module 2, [further steps are required]. Fig. 7 and Fig. Figure 8 shows a storage position of the tool changer 25 that is free. By opening the receptacles 12 on the optical module 2, the fastening means 16 of the powder nozzle 15 are released, so that the powder nozzle 15 is detached from the optical module 2 and can be placed in a free storage position of the tool changer 25.

[0069] The optical module 2 is then moved to a different position on the tool changer 25, where another powder nozzle 15, having a larger or smaller axial dimension, is located. The optical module 2 is then moved by means of the positioning axes 18 so that the fastening means 16 of the additional powder nozzle 15 engage in the receptacles 12 on the optical module 2. By closing the receptacles 12, the powder nozzle 15 can be attached to the optical module 2 and removed from the tool changer 25.

[0070] Automatic powder nozzle changing 15 is particularly useful when the focal length of the laser beam is changed by replacing the focusing lens 14. Since the powder nozzle 15 is intended to direct the material powder to the focal point of the laser beam, its axial length must be selected according to the laser beam's focal length. As listed in Table 1, the focal length of the focusing lens 14 can be, for example, 200 mm or 300 mm. Accordingly, the tool changer 25 of the machine 1 can be equipped with corresponding powder nozzles 15 that direct material powder to a focal point located, for example, 200 mm or 300 mm away from the focusing lens 14.

[0071] A material powder can be supplied to the operating point of the machine 1, i.e., in the immediate vicinity of the focal point of the laser beam, via the powder nozzle 15. For this purpose, the powder nozzle 15 has one or more channels through which the material powder is guided. When the powder nozzle 15 is attached to the optical module 2, a connection is established between the channels for the material powder and corresponding lines in the optical module 2. The powder nozzle 15 and the optical module 2 each have suitable interfaces for connecting the channels and the lines. Furthermore, the powder nozzle 15 has one or more cooling channels in which a fluid coolant, in particular water, can circulate to cool the powder nozzle 15. The optical module 2 has corresponding lines for supplying and removing the coolant, as well as interfaces for connecting the lines to the cooling channels of the powder nozzle 15.

[0072] Furthermore, the powder nozzle 15 can supply a protective gas to the operating point of the machine 1, so that undesirable reactions during the melting of the material powder at the focal point of the laser beam can be largely suppressed. The protective gas serves primarily to displace oxygen from the air. Inert gases such as argon can be used as protective gases. The optical module 2 has corresponding lines for supplying the protective gas. The protective gas can also be supplied together with the material powder as a carrier gas. Thus, the protective gas serves both to prevent a reaction with atmospheric oxygen and to convey the material powder.

[0073] During the automatic exchange of the powder nozzle 15, the cooling lines of the optical module 2 are automatically connected or disconnected from the cooling channels of the powder nozzle 15 via the corresponding interfaces. Similarly, the lines for material powder in the optical module 2 are also automatically connected or disconnected from the material powder channels in the powder nozzle 15 via the corresponding interfaces. The interfaces for the lines and channels can be designed to be detachable and, for example, controlled hydraulically or pneumatically.

[0074] An automatic change of the focusing lens module 13 can be performed in a similar manner to the automatic change of the powder nozzle 15. In this process, the upper part of the tool changer 25, including the focusing lens modules 13, is moved into the process chamber 22 by means of the positioning axis 25a. However, to change the focusing lens module 13, a powder nozzle 15 attached to the optical module 2 must first be detached. This is done as described above by placing the powder nozzle 15 in a free storage position of the tool changer 25. The positioning axes 18 then move the optical module 2 to a position where the tool changer 25, with its multiple focusing lens modules 13, is located. The focusing lens module 13, which is attached to the optical module 2, can be released by opening the receptacles 11 on the optical module 2, so that the focusing lens module 13 can be detached from the optical module 2 and placed at a free storage position of the tool changer 25.Subsequently, another focusing lens module 13 can be attached to the optical module 2. For this purpose, the optical module 2 is moved so that the fastening elements 16 of the focusing lens module 13 engage in the receptacles 11 on the optical module 2. The receptacles 11 on the optical module 2 can then clamp the fastening elements 16, for example, via a hydraulic, pneumatic, or spring-loaded mechanism, to secure the focusing lens module 13 to the optical module 2. The tool changer 25 can then be moved back into the detachable tool chamber, and machining of the workpiece can be started or continued.

[0075] The required travel distances of the positioning axes 18, 25a, and 25b can be stored in a memory of the machine control, enabling fully automatic exchange of the focusing lens module 13 or the powder nozzle 15. This exchange can therefore be integrated into a machining process. As a result, a suitable combination of focusing lens 14 and powder nozzle 15 can be attached to the optical module 2 for each machining operation.

[0076] The first deflecting mirror 6 has means for cooling and monitoring its temperature. The second deflecting mirror 7 is a dichroic mirror, which also has means for cooling and monitoring its temperature. For the wavelength of the laser beam, which lies, for example, in the infrared spectral range, the dichroic mirror 7 is reflective. For visible light, however, the dichroic mirror can be transparent. A camera 9 for monitoring the manufacturing process can be positioned behind the dichroic mirror 7. The camera 9 is positioned with its view along the laser beam through the dichroic mirror and, via the focusing lens 14, onto the focal point of the laser beam. Thus, the camera 9 can be used to monitor the working point on the workpiece or the molded part to be manufactured.

[0077] The optical module 2 has interfaces for receiving control signals from a machine control system. These control signals can, for example, cause the collimation lens changer 3 to perform a collimation lens change. Furthermore, the measured temperatures of the collimation lenses 4, the deflecting mirrors 6, 7, or the other optical components can be transmitted to the machine control system via these interfaces.

[0078] Fig. Figure 3 shows another sectional view of the optical module 2 according to the invention and the exemplary embodiment. The section of the illustrated view passes through the same plane as in Figure 3. Fig. 2, however, the viewing direction is directed from the opposite side towards the optical module 2. A beam path 17 of the laser beam is shown as a dashed line. In the Fig. In the view shown in Figure 3, both a rotation axis 5 of the collimation lens changer 3 and the fiber coupler 10 can be seen.

[0079] Further details of the collimation lens changer 3 according to the invention are described with reference to the figures in the Fig. Sectional views 4 to 6 are described. Fig.Figure 4 shows a quarter section in perspective view of an upper region of the optical module 2. Part of the housing 8 of the optical module 2 is still visible. Beneath the part of the housing 8 that covers the upper region of the optical module 2, the collimation lens changer 3 with four collimation lenses 4 is shown. The collimation lens changer 3 of the illustrated embodiment is designed as a turret, rotatably mounted about a vertical axis of rotation 5. An actuator (not shown) is operatively connected to the axis of rotation 5, so that the collimation lens changer 3 can be rotated about the axis of rotation 5 by actuating the actuator, thus enabling a change of the collimation lenses 4. The axis of rotation 5 is shown centrally in the cross-section. The collimation lens 4, which is arranged below the fiber coupler 10, is located in the beam path of the laser.The interior of the housing 8 of the optical module 2 is designed in such a way that the collimation lens changer 3 can rotate within it.

[0080] An electric motor, in particular a servo motor or a stepper motor, can be used as the actuator for rotating the collimation lens changer 3 about the axis of rotation 5. The correct setting of the collimation lens changer 3 can be monitored, in particular, by the camera 9 arranged in the optical module 2, for example by observing the location of the focal point of the laser beam. The laser beam should strike the collimation lens 4 and the other optical components in the beam path as centrally as possible.

[0081] As seen in the cross-sectional view of the Fig. As shown in Figure 6, the collimation lens changer 3 of the exemplary embodiment has a rounded rhombus shape, which results, among other things, from the lens diameters of the collimation lenses 4 used. Fig.Figure 6 also shows that the collimation lenses 4 are arranged in different positions along the Z-axis, which runs parallel to the axis of rotation 5, according to their focal length. The axial position of the collimation lenses 4 can be adjusted. Thus, the lens position can be pre-adjusted before the collimation lens changer 3 is installed in the optical module 2, ensuring that the laser beam is correctly collimated by each installed collimation lens 4.

[0082] Fig.Figure 5 shows a longitudinal section through the axis of rotation 5 of the collimation lens changer 3. In this sectional view, bearings 5a are shown at the top and bottom, by means of which the axis of rotation 5 is rotatably mounted. A flange on an upper portion of the axis of rotation 5 serves to detachably attach the axis of rotation 5 to the cover housing 8 of the optical module 2. The lower bearing 5a is detachably attached to a support element arranged parallel to the cover in the housing 8. This design allows for easy replacement of the collimation lens changer 3 if necessary.

[0083] The collimation lenses 4 are each detachably mounted in the collimation lens changer 3, allowing individual lenses 4 to be easily and quickly replaced as needed. Furthermore, each collimation lens 4 is protected by a protective glass to shield it from contamination and mechanical damage. This protective glass prevents the need to replace significantly more expensive lenses, thus avoiding damage or contamination. The protective glasses are also detachably mounted in the collimation lens changer 3, allowing for quick and easy replacement of individual lenses as required. The protective glasses may feature an anti-reflective coating to prevent disruptive reflections of laser light back into the laser.

[0084] The collimation lens changer 3 according to the one in the Fig.The embodiment shown in Figures 4 to 6 has four positions for the detachable mounting of collimation lenses 4. These four positions are designed as cylindrical openings in a solid housing, preferably made of a metal, such as an aluminum or steel alloy, or of a ceramic material. The collimation lenses 4 can also be pre-mounted in cylindrical sockets, so that the collimation lenses 4 with their sockets can be easily inserted into the cylindrical openings and secured therein. In contrast to the illustrated embodiment, the collimation lens changer 3 can also have more than four collimation lenses 4. For example, embodiments with two, three, five, six, seven, or more collimation lenses 4 are conceivable.

[0085] The collimation lens exchanger 3 may contain means for cooling the collimation lenses 4. As in Fig.Figure 6 shows that the collimation lens changer 3 has a solid housing. The housing can, for example, be milled from a single piece of metal. Cooling of the collimation lenses 4 can be achieved, for example, by cooling the housing of the collimation lens changer 3. For this purpose, the housing of the collimation lens changer 3 can have a multitude of cooling channels 3a through which a suitable fluid coolant flows. Cooling the collimation lens changer 3 prevents damage to the collimation lenses 4 caused by temperature fluctuations. Furthermore, cooling can reduce the thermal lens effect.

[0086] In the Fig. 5 and Fig.Figure 6 shows several cooling channels 3a in the collimation lens changer 3. Two axial cooling channels run axially through the axis of rotation 5 of the collimation lens changer 3. One of these two axial cooling channels serves as the supply for the coolant, the other as the return for the coolant removal, so that the coolant can circulate in a loop through the collimation lens changer 3a. In the sectional view of the Fig.Figure 6 shows four radial cooling channels 3a of the collimation lens changer 3. The radial cooling channels 3a extend radially outwards from the axial cooling channels along the axis of rotation 5 through the collimation lens changer 3. In a second plane parallel to the section plane, further radial cooling channels 3a extend through the collimation lens changer 3. The radial cooling channels 3a of the two planes are connected via cooling channels perpendicular to the section plane through the housing of the collimation lens changer 3, thus enabling the coolant circulation. The coolant can therefore cool the collimation lens changer 3. In particular, the housing of the collimation lens changer 3 is cooled. The collimation lenses 4 are attached to the housing of the collimation lens changer 3.This allows heat transfer between the collimation lenses 4 and the housing of the collimation lens changer 3, so that cooling the housing via the cooling channels 3a cools the collimation lenses 4. The coolant can be supplied to the optical module 2 via coolant lines. The coolant lines can be detachably connected to coolant channels in the optical module 2 or in or on the optical components via suitable fittings.

[0087] The operating principle of laser cladding is explained using the following examples: Fig. 10 illustrated. Fig.Figure 10 shows the tip 30 of a powder nozzle 15 near a workpiece W to be processed. A focused laser beam L is coaxial with the powder nozzle 15 and is focused on a working point on the workpiece W. The material powder P is guided coaxially to the laser beam L through the powder nozzle 15 to the focal point of the laser beam L on the workpiece W. A shielding or carrier gas G also flows through the powder nozzle 15 and transports the material powder P. The shielding gas G, for example argon, also serves to prevent unwanted reactions of the heated material powder P or the workpiece W with atmospheric oxygen.

[0088] The features disclosed in the foregoing description, the claims and the drawings can be important for the realization of the invention in its various embodiments, both individually and in any combination. Reference symbol list 1 laser machine tool 2 Optical module 3 collimation lens changers 3a Cooling channel 4 Collimation lens 5 axis of rotation 5a Warehouse 6 first deflecting mirror 7. Second deflecting mirror (dichroic mirror) 8 cases 9 Camera 10 fiber optic couplers 11 Interface for focusing lens 12 Interface for powder nozzle 13 Focusing lens module 13a Thermocouple 13b Thermocouple interface 14 Focusing lens 14a Protective glass 15 powder nozzle 15a Powder nozzle flange 15b Powder nozzle tip 15c annular gap 15d Material powder channel 15e Cooling channel 15f Coolant coupling 15g material powder inlet 15l slats 15w honeycomb structure 16 clamping bolts 17. Laser beam path 18 axes of adjustment of the tool 19 axes of the workpiece table 20 Workpiece table 21 machine frames 22nd Tribunal 23 Process room door 24" Display 25 tool changers 25a Positioning axis of the focusing lens changer 25b Adjustment axis of the powder nozzle changer L laser beam W workpiece P workpiece powder G Shielding gas and / or carrier gas

Claims

[1] Optical module (2) for a machine (1) for processing workpieces and / or for producing shaped bodies by selectively solidifying material powder into contiguous areas using a laser beam, comprising: a housing (8) with means for detachably attaching the optical module (2) to the machine (1) and a collimation lens changer (3) detachably arranged in the housing (8) with at least two collimation lenses (4) movable into a beam path of the laser beam for collimating the laser beam, wherein the collimation lens changer (3) is designed as a turret and is rotatably mounted in the housing via a vertical axis of rotation (5), and the collimation lens changer (3) comprises: a case; a mechanism for automatically changing the collimation lenses (4); a plurality of cooling channels (3a) in the housing of the collimation lens changer (3), through which a fluid coolant flows to cool the collimation lenses (4); and Means for measuring the temperature of the collimation lenses (4), wherein a first axial cooling channel as a supply for the fluid coolant and a second axial cooling channel as a return for the fluid coolant pass through the axis of rotation (5), and wherein the axial cooling channels are connected to cooling channels (3b) extending radially outwards in a first plane through the housing of the collimation lens changer (3), wherein further radial cooling channels run through the collimation lens changer (3) in a second plane parallel to the first plane, and wherein the radial cooling channels (3a) of the two planes are in flow communication with each other via cooling channels running perpendicular to the first and second planes through the housing of the collimation lens changer (3) in order to enable the coolant circulation. [2] Optical module (2) according to claim 1, wherein the optical module (2) has means for connecting supply lines for a process gas. [3] Optical module (2) according to one of the preceding claims, wherein the optical module (2) comprises means (11) for attaching an automatically interchangeable focusing lens module (13). [4] Optical module (2) according to one of the preceding claims, wherein the optical module (2) has means (12) for attaching an automatically replaceable powder nozzle (15). [5] Optical module (2) according to one of the preceding claims, wherein the optical module (2) has means (10) for connecting an optical fiber for providing a laser beam. [6] Optical module (2) according to one of the preceding claims, wherein the optical module (2) comprises a camera (9) for monitoring a processing process. [7] Machine (1) for processing workpieces and / or for producing shaped bodies by selectively solidifying material powder into contiguous areas using a laser beam, characterized by that the machine has an optical module (2) according to one of claims 1 to 6.

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