DE102017215840A1 - Replaceable focusing module - Google Patents

Abstract

The present invention relates to a focusing module (13) for a machine (1) for machining workpieces and / or for producing shaped bodies by locally selective solidification of material powder to coherent areas by means of a laser beam. The focusing module (13) comprises a substantially cylindrical carrier housing and a focusing optics (14). According to the invention, the focusing module (13) has fastening means (16) for releasably securing the focusing module (13) to a laser processing head (2) of the machine (1).

Description

The present invention relates to a focusing module for a machine for processing workpieces and / or for producing shaped articles by locally solidifying material powder to coherent areas by means of a laser beam. The invention relates in particular to a focusing module for a machine for the production of shaped articles according to the principle of selective laser melting, selective laser sintering or laser deposition welding. In addition, the focusing module according to the invention can also be used for example in a machine for laser welding, laser drilling, laser hardening or laser cutting. In summary, for the various types of machines for processing / manufacturing / producing a workpiece or a shaped body with a laser beam, the term laser machine tool or simply a machine is used below.

background

With the method of selective laser melting, laser sintering or laser deposition welding, molded articles, such as machine parts, tools, prostheses, jewelry, etc., can be manufactured or machined according to geometric description data of the respective molded articles, for example, by layering 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 predetermined area, which corresponds to a selected cross-sectional area of the model of the molded body, so that the material powder is remelted in the irradiated areas to coherently solidified sections. A protective gas can prevent oxidation during the build-up process. After cooling, a layer of material is created, which can be processed mechanically.

The prior art relating to the field of selective laser melting is, for example, the DE 10 2015 222 689 A1 directed. Furthermore, a laser machine tool of the type mentioned, for example, from EP 2 052 845 A2 known. A machine tool for build-up welding, for example, in the published patent application DE 10 2013 224 649 A1 described. In the German Offenlegungsschrift DE 196 30 147 A1 For example, a connection head for machining a workpiece by means of a laser beam having an automatic focusing lens changing mechanism formed as a revolver will be described.

The article "Laser unit makes build-up welding on machining center possible" by Nowotny et al. in "MM Das Industriemagazin", 17/2009, page 42 ff., describes a laser processing optics, which is used via a steep taper in the milling spindle of a CNC machine. In the laser focal point weld metal (material powder) is fed through a powder nozzle. The workpiece can be milled in the same machine.

In the patent application US 2017/0136578 A1 a generic machine for layered construction of a three-dimensional molded body is described by melting a material powder. The material powder is conducted by means of a powder nozzle attached to a laser processing head to an operating point, where it is melted by a laser beam, which is passed through the powder nozzle. The machine has a powder nozzle changing unit which exchanges the powder nozzle attached to the laser processing head.

From the European patent application EP 2 062 679 A1 For example, a machining head for a laser processing machine is known, which has a stationary part in the form of a laterally open housing, which encloses a space for a change module, which can be separated as a whole from the stationary part of the machining head, without the stationary part disassembled into individual parts must become. The interchangeable module comprises a focusing optics, which is movable coaxially to the laser beam, and a measuring device for determining the position of the focusing optics.

A laser machine tool is usually operated with a laser that provides a laser beam with an output power of several hundred to several thousand watts, which are usually operated in continuous operation ("CW"). Decisive for the machining process can be in particular the energy transfer from the laser beam to the material powder. This is influenced on the one hand by the absorption capacity of the material powder and on the other hand by the intensity of the laser beam. In addition to the absolute laser power, the beam diameter determines the melting process. The beam diameter of the laser beam is usually determined by the focal length of a focusing optics and determines the beam diameter of the collimated laser beam in front of the focusing optics. The beam diameter of the collimated laser beam can be determined in particular by the focal length of a collimating optics. Thus, the beam diameter of the focused laser beam, or the waist of a Gaussian laser beam, can be adjusted by suitable choice of the collimating optics, without changing the focal length of the focusing optics.

According to the state of the art, essentially two types of machines are known for machining workpieces and / or for producing shaped bodies by locally solidifying material powder into contiguous areas by means of a laser beam, in particular by selective laser melting or selective laser sintering. The types of machines differ, among other things, in the way the material powder is provided. In a first type of machine, a powder bed is built up in layers. In a second type of machine, the material powder is provided by means of a powder nozzle at the point of machining. In particular, the present invention relates to machines in which the laser beam is provided by means of a laser processing head.

The mechanical structure for moving the laser processing head and / or the workpiece, for example, as in a known five-axis machining center, wherein instead of a mechanical tool, the laser processing head is provided. Machine tools have also been available on the market for some years now, which permit both laser machining and machining, for example with a milling tool. In such hybrid machining centers, for example, the laser processing head may be attached to the tool take-up spindle.

The laser processing head may comprise a plurality of optical components for manipulating the laser beam, such as for collimating, focusing, positioning, monitoring, switching and / or modulating the laser beam and the power of the laser beam, respectively. It has proven to be advantageous to combine as many components as possible in a preassembled as an exchangeable component optical module, which can be releasably secured by suitable means on the machine, in particular on a control axis of the machine. As a result, the maintenance of a laser machine tool can be simplified and accelerated, so that the machine can be used more efficiently, since an idle time of the machine can be shortened. The focusing module is usually attached to the laser processing head or the optical module.

Summary

The present invention has for its object to provide a focusing module that can be replaced quickly and easily automatically. The object is achieved by a focusing module with a substantially cylindrical carrier housing, in which a focusing optics is arranged. According to the invention, the focusing module has fastening means for releasably securing the focusing module to a laser processing head of the machine. In particular, the focusing module with the focusing optics can be changed automatically during a machining process, so that the diameter of the laser beam at the operating point and correspondingly the intensity of the laser beam at the operating point during the machining process are automatically adjustable. By virtue of the fact that the focusing module has fastening means for detachable fastening, a change of the focusing optics can be integrated into the machining process without the need for a step to be performed manually. The operating point of the laser beam generally corresponds to the focal point of the laser beam focused by the focusing optics.

The focusing optics may comprise at least one focusing lens. The focusing optics may also include a plurality of lenses. In a focusing lens with a combination of multiple lenses aberrations, for example due to spherical aberration and / or astigmatism, can be compensated.

In particular, the laser processing head has a detachably mountable optical module in or on which optical components for collimating and focusing the laser beam can be arranged or fastened. In particular, the focusing module can be fastened to the optical module. A collimating optics arranged in the optics module serves for collimating a laser beam divergently coupled into the optics module. For example, the laser beam can be coupled into the optical module by means of an optical fiber.

The optical module can accordingly have means for connecting an optical fiber, in particular a fiber coupler. Since an optical fiber can transport laser light over many meters, it is possible to place the laser in a protected location away from the process chamber. The distance between Collimation optics and end of the optical fiber is approximately equal to the focal length of the collimating optics. The collimated laser beam can be focused by the focusing module attached to the optics module with a focusing optics to a focal point. The laser beam thus leaves the optics module as a focused beam.

On the one hand, optical components of laser machine tools can be subject to increased wear due to the relatively high laser powers. On the other hand, especially in a hybrid machine that can perform both laser machining and machining manufacturing processes, contamination of optical components such as coolant, dust, chips and other particles may occur. Furthermore, the material powder can contribute to the contamination of optical components. Dirt particles deposited on an optical component can, especially at high laser powers, lead to a high heat effect on the optical component and thus to its damage. Therefore, it is desirable if optical components can be replaced quickly and easily in the event of damage or contamination. On the one hand, this is achieved by the fact that the entire optical module can be detachably fastened as a preassembled subassembly to a positioning axis and is therefore easily replaceable. On the other hand, interchangeable optical components allow a quick change without removing the entire optical module. For example, the collimation optics changer allows a fast automatic change of the collimating optics without the need to replace the entire collimation changer or the optics module.

The optical components arranged in or on the optical module can each be detachably fastened in or on the housing of the optical module. Thus, on the one hand take place during operation of the machine, an automatic change of the optical components. On the other hand, an optical module to be serviced can be brought back into an operable state by exchanging individual optical components. For example, the collimator changer can be detachably arranged as an exchangeable module in the housing of the optical module and thus exchanged during maintenance of the optical module.

Advantageous embodiments and developments, which can be used individually or in combination with each other, are the subject of the dependent claims.

The focusing module can preferably be connected via at least two clamping bolts with a laser processing head of the machine, in particular with an optical module. The optical module or the laser processing head can each have corresponding receptacles for the clamping bolts. The recordings can be designed in particular as electromagnetically, hydraulically or pneumatically actuated or tensioned by a spring clamping mechanisms.

By providing means for attaching an automatically exchangeable focusing module, an automatic change of the focusing optics can take place. This can then be replaced fully automatically similar to a tool of a machining center during the manufacturing or machining process. By automatically changing the focusing optics and the collimation optics, the beam diameter of the laser beam in the focus can be set within a wide range, depending on the requirements. The clamping bolts allow a fast and secure fastening of the focusing module to the optical module. Furthermore, the clamping bolts ensure that the focusing module can be attached to the optical module with a high positional accuracy.

The focusing module preferably comprises a substantially cylindrical carrier housing with a circular cross section, which is made for example of a metal or a metal alloy. In the carrier housing the focusing optics is arranged. Preferably, the focusing optics can be releasably secured in the carrier housing of the focusing module, so that replacement of the focusing optics is possible. For example, the carrier housing may have an internal thread. By means of suitable rings with an external thread, the focusing optics and / or at least one protective glass can be secured in the carrier housing.

The focal length of the focusing optics may be, for example, a few hundred millimeters, in particular 100 mm, 200 mm or 300 mm or any focal length between 100 mm and 500 mm. The focusing optics can be a conventional converging lens or a combination of several lenses. The focusing module preferably has means for measuring the temperature of the focusing optics. It is further preferred that the focusing module has means for cooling the focusing optics.

The focusing optics is preferably positioned as a function of their focal length in the axial direction in the carrier housing. In this way it can be achieved that the distance of the focal point from Laser processing head regardless of the focusing optics used is always the same. This has the advantage that the laser processing head can always be guided at the same distance from the workpiece to be machined. Thus, the machine control does not have to perform pitch correction after changing the focusing optical focal length.

The focusing module may have at least one protective glass for protecting the focusing optics from contamination. The protective glass can also protect the focusing optics from mechanical influences. The protective glass is preferably detachably fastened in the carrier housing of the focusing module. If dirty, the protective glass can be replaced. Preferably, a protective glass is arranged on both sides of the focusing optics in the axial direction in the carrier housing of the focusing module, so that the focusing optics are protected from contamination and mechanical action from both sides.

The focusing module may comprise means for measuring the temperature of the at least one protective glass and / or the focusing optics. Thus, contamination of a protective glass or the focusing optics can be detected, for example, by a rise in temperature. As means for measuring the temperature, for example, at least one thermocouple can be used. To transmit a temperature measurement signal from the focusing module to the machine, the focusing module can have at least one interface.

The interface can preferably be connected to a corresponding interface on the laser processing head, or on the optical module. The interfaces are preferably designed so that they automatically connect to each other when attaching the focusing module. As an interface, for example, a simple electrical contact or a plug contact can be used.

The beam path through the optical module is preferably sealed gas-tight, so that a sealing gas atmosphere can be maintained. In particular, inert gases such as nitrogen or argon can be used as the sealing gas. It is important, above all, that the sealing gas is free of particles that can pollute the optical components. Preferably, the entire housing of the optical module is sealed gas-tight.

To build up the sealing gas atmosphere in the housing of the optical module, the optical module preferably has corresponding gas supply lines and / or means for connecting feeders. Instead of sealing the housing in a gas-tight manner, the housing can also be constructed in such a way that it is possible to build up a slight overpressure in the housing by supplying the barrier gas so that it is possible to prevent particles of dust or material from getting inside the optics module.

list of figures

Further advantageous embodiments will be described in more detail below with reference to an embodiment shown in the drawings, to which the invention is not limited.

• 1: eine Werkzeugmaschine mit einem Optikmodul zum Herstellen bzw. Bearbeiten eines Formkörpers bzw. Werkstücks mittels Laserstrahlung.
• 2: eine perspektivische Schnittansicht eines Ausführungsbeispiels eines Optikmoduls.
• 3: eine weitere perspektivische Schnittansicht des in 2 gezeigten Ausführungsbeispiels des Optikmoduls.
• 4: eine perspektivische Ansicht eines Ausführungsbeispiels einer Werkzeugmaschine zum Herstellen bzw. Bearbeiten eines Formkörpers bzw. Werkstücks mittels Laserstrahlung.
• 5: eine perspektivische Ansicht eines Werkzeugwechslers für eine Werkzeugmaschine zum Herstellen bzw. Bearbeiten eines Formkörpers bzw. Werkstücks mittels Laserstrahlung.
• 6: (A) eine teilgeschnittene perspektivische Ansicht und (B) eine perspektivische Ansicht einer austauschbaren Pulverdüse.
• 7 eine Illustration des Wirkungsprinzips des Laserauftragsschweißens.
• 8 (A) eine perspektivische Ansicht eines erfindungsgemäßen austauschbaren Fokussiermoduls, (B) und (C) jeweils Schnittansichten des austauschbaren Fokussiermoduls mit unterschiedlichen Brennweiten der Fokussieroptik.

They show schematically:

• 1 a machine tool with an optical module for producing or processing a shaped body or workpiece by means of laser radiation.
• 2 : A perspective sectional view of an embodiment of an optical module.
• 3 : another perspective sectional view of the in 2 shown embodiment of the optical module.
• 4 : A perspective view of an embodiment of a machine tool for producing or processing a shaped body or workpiece by means of laser radiation.
• 5 : A perspective view of a tool changer for a machine tool for producing or processing a shaped body or workpiece by means of laser radiation.
• 6 (A) is a partially cutaway perspective view and (B) is a perspective view of a replaceable powder nozzle.
• 7 an illustration of the principle of action of laser deposition welding.
• 8 (A) a perspective view of an exchangeable focusing module according to the invention, (B) and (C) each have sectional views of the exchangeable focusing module with different focal lengths of the focusing optics.

Detailed description of the invention with reference to an embodiment

In the following description of a preferred embodiment of the present invention, like reference characters designate like or similar components.

1 shows a schematic representation of a machine 1 for machining a workpiece 30 and / or for producing a shaped body 30 by site-selective solidification of material powder to coherent areas by means of laser radiation. The machine 1 has a machine frame 21 on, on the indirectly over intermediate axles 18 . 19 on the one hand a workpiece table 20 and on the other hand, an optical module 2 are attached. The adjusting axles 18 . 19 can each have a plurality of translational (X, Y, Z) or rotational (φ, λ, θ) axes which are adjustable in accordance with a machine control. The design can for example be such that the optical module 2 via one, two or three translatory adjusting axes 18 (X and / or Y and / or Z) on the machine frame 21 is attached while the workpiece table 20 over one, two or three rotary control axes 19 on the machine frame 21 is attached. Such a laser machine tool 1 generally has a (not shown) completed cabin in which, for example, a protective gas atmosphere can be constructed, and shields the working space from contamination.

On the workpiece table 20 can be a workpiece 30 be releasably secured for editing. Alternatively, on the work table 20 a shaped body 30 be built up in layers by site-selective solidification of material powder.

At the machine 1 it may be, for example, a five-axis laser machine tool for producing shaped bodies by means of location-selective solidification of material powder to coherent areas by means of laser radiation. The optics module 2 in this case is detachable on the adjusting axles 18 fastened so that it can be replaced quickly and easily when needed, for example, for maintenance. In such a five-axis laser machine tool is the optical module 2 via three translatory adjusting axes 18 (X, Y and Z) on the machine frame 21 attached and the workpiece table 20 is arranged on the machine frame via two rotary axes.

An exemplary illustration of a five-axis laser machine tool 1 for the production of moldings by site-selective solidification of material powder to coherent areas by means of laser radiation is in perspective 4 shown. The illustrated embodiment corresponds essentially to the in 1 schematically illustrated machine 1 , The workpiece table 20 and the optics module 2 are in a substantially through a process room door 23 lockable process chamber 22 arranged. One outside the process chamber 22 arranged display 24 serves as an interface between user and machine control. On this display 24 For example, measured values and / or warning messages and / or control applications can be displayed.

The machine tool 1 includes a tool changer 25 that by means of adjusting axles 25a . 25b laterally into the process chamber 22 can be driven into it. A detailed view of the tool changer 25 is in 5 shown. On the tool changer 25 can a variety of focusing modules 13 and a plurality of powder nozzles 15 to be ordered. The in 5 illustrated tool changer 25 has three storage positions for powder nozzles 15 with different axial length.

The tool changer 25 further includes a shelf for at least two focusing modules 13 with focusing optics 14 different focal length. By means of two adjusting axes 25a . 25b can the focus modules 13 or the powder nozzles 15 in the process chamber 22 be moved so that they are on the optics module 2 can be attached.

A method of changing the powder nozzles 15 or the focusing modules 13 will be described below.

The tool changer 25 can by means of adjusting axles 25a . 25b into one by means of a sliding partition from the process chamber 22 be moved separable tool chamber. In the Tool chamber are the focus modules 13 and the powder nozzles 15 protected from contamination, for example, by material powder or by welding fume, if a machining of the workpiece in the process chamber 22 is carried out.

In 2 is an optics module 2 shown on a positioning axis 18 is detachably mounted. The adjusting axle 18 is, for example, a translational axis which can be moved in the Z direction and which can be arranged on two further translation axes which can be moved in the X and Y directions, so that the optical module 2 is movable in all three spatial directions. The optics module 2 is especially so on the positioning axis 18 Mounted the laser beam vertically downwards (parallel to the direction of gravity or in the Z direction) from the optics module 2 exit. By moving the positioning axes 18 Thus, a focus of the focused laser beam in three dimensions can be moved in space to edit a workpiece or to build a shaped body in layers. Thus, a molded article as in a 3D printer by merging material powder can be built up in layers.

The optics module 2 has a housing 8th in which a plurality of optical components is arranged. The housing 8th serves on the one hand as a mechanical platform for arranging the optical components as well as for protecting the optical components against mechanical influences. In the case 8th a barrier gas atmosphere can be built up. For example, overpressure can prevent particles and dirt from entering the housing.

At an upper area of the housing 8th is a fiber coupler 10 arranged, via which a laser beam from an optical fiber can be coupled. By using an optical fiber, laser light from a laser beam source can reliably become the optical module 2 be directed. The flexible optical fiber allows the optics module 2 , And thus to move the laser beam without having to move the laser beam source itself. Further, an optical fiber can provide a laser beam with a particularly uniform beam profile.

As a laser beam source, for example, a high-power solid-state laser can be used. These include, for example, doped YAG lasers. In particular, a Ytterbium-doped YAG disc laser with a wavelength of 1030 nm can serve as a laser beam source. Alternatively, a fiber-guided diode laser with a wavelength of 1020 nm may be used as the beam source. Diode lasers can provide laser beams with a power of several watts up to several thousand watts. Thus, sufficient laser power can be provided for various machining and manufacturing processes.

Directly below the fiber coupler 10 is the collimation optics changer 3 in the case 8th of the optics module 2 arranged. A collimation optics 4 with a first focal length of, for example, 80 mm is so in the collimating optical changer 3 arranged so that the emerging from the fiber laser beam is collimated to a diameter of about 36 mm. The collimation optics changer 3 can be more collimation optics 4 having focal lengths of, for example, 50 mm, 60 mm and / or 100 mm or more. This can be used to provide collimated laser beams with diameters between approx. 10 mm and 100 mm. As collimation optics 4 For example, suitable types of converging lenses may be used. A collimation optics 4 may consist of a single lens or comprise a plurality of lenses. Material, coating and other lens properties can be selected depending on the laser wavelength and laser power used.

The collimated laser beam is from two in the optics module 2 arranged deflecting mirrors 6 . 7 on a focusing optics 14 directed, which focuses the laser beam. The position or the orientation of the two deflecting mirrors 6 . 7 is preferably independently adjustable, so that an adjustment of the beam path of the laser beam can be made automatically or manually. The correct adjustment of the laser beam, for example, from the camera 9 be monitored. In particular, the deflection mirror 6 . 7 be controlled controlled by the machine control. For this purpose, the deflection mirror 6 . 7 may each be arranged on adjustable holders, which can be controlled in each case by means of control signals via the machine control. The optics module 2 may have suitable interfaces to releasably connect signal lines for machine control.

The focal length of the focusing optics 14 can be between 50 mm and 500 mm, for example. Preferably, the focal length of the focusing optics 14 200 mm or 300 mm. The focusing optics 14 is in an automatically exchangeable focusing module 13 arranged, via an attachment mechanism 11 . 16 on the optics module 2 can be attached. Thus, by changing the focus module 13 also the focal length of the focusing optics 14 be changed fully automatically.

Seven exemplary combinations of focal lengths of the collimation optics 4 and the focusing optics 14 are shown in Table 1 below. Table 1 also lists, by way of example, resulting values of 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. In particular, 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 optics by a larger beam diameter of the collimated laser beam in front of the focusing optics. A larger beam diameter of the collimated laser beam has the advantage that the optical elements in the optical module 2 are exposed to a lower laser intensity. Thus, the optical elements are less likely to be damaged because, for example, they are less heated. Table 1: Seven example combinations of collimation optical focal length and focusing optical focal length: size unit Ex.1 Ex. 2 Example 3 Example 4 Example 5 Ex. 8 Example 7 power W 4000 4000 4000 4000 4000 4000 4000 Focal length of the collimation optics mm 50 60 80 100 60 80 100 Diameter of the collimated beam mm 22 27 36 45 27 36 45 Focal length of the focusing optics 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

An exemplary embodiment of the focusing module 13 is in 8A to C shown. 8A shows a perspective view of a focusing module 13 with a substantially cylindrical carrier housing, which is preferably made of a metal with the smallest possible thermal expansion coefficient. According to the examples of Table 1 shows 8B a focusing module 13 with a focusing optics 14 , which has a focal length of 200 mm, and 8C a focusing module 13 with a focusing optics 14 which has a focal length of 300 mm. The focusing optics 14 the different focal lengths are so in the different focusing modules 13 arranged that the resulting focus of the laser is always in the same place.

At an upper edge of the focusing module 13 are fastening means, for example two clamping bolts 16 arranged. The fasteners 16 also serve to ensure the highest possible positioning accuracy of less than 1 mm. This is especially important for the accurate beam guidance of the laser beam through the powder nozzle and to the correct operating point. If deviations nevertheless occur, this can be done by the camera 9 detected and by the deflection mirror 6 . 7 Getting corrected. The focusing module 13 has at least one protective glass 14a to protect the focusing optics 14 from soiling or damage. Preferably, as in the sectional drawings of 8B and C shown on both sides of the focusing optics 14 one protective glass each 14a in the focusing module 13 arranged to the focusing optics 14 from both sides to protect against contamination or mechanical impact.

The temperature of the at least one protective glass 14a can each be through a probe 13a be monitored. In 8B and C only the temperature of the upper protective glass 14a , which is first hit by the laser beam, through a probe 13a monitored shown. As a sensor, for example, a temperature-dependent resistor (NTC resistor) or a thermocouple can be used. The thermocouple may in particular be a wire made of a platinum alloy. Similarly, the temperature of other optical components in the optics module 2 , in particular the Kollimationsoptiken 4 , the protective glasses of collimation optics 4 , the deflecting mirror 6 . 7 and / or the focusing optics 14 be monitored.

One from the temperature sensor 14a generated analog measurement signal is via interfaces 13b at the focusing module 13 on signal lines in the optics module 2 forwarded. From there, the measurement signal is output to a machine control and converted into a temperature value, so that the temperature of a optical component of the optical module 2 can be output in degrees Celsius. The measured temperature values can be shown on the display, for example 24 are displayed. In the machine control, a threshold value of the temperature can be stored for each optical component. If the measured temperature of an optical component exceeds the stored threshold, then a warning signal can be generated. The warning signal can be output as a warning to a user, for example. The warning can for example be on the display 24 or visualized by means of a warning light. Additionally or alternatively, a shutdown of the laser can be made to avoid damage to the optical component.

The interfaces 13b may also serve to provide the machine control with a successful attachment of a focusing module 13 to signal. Accordingly, the machine controller can detect that the focusing module 13 successfully solved and filed, if one over the interfaces 13b transmitted signal is interrupted.

Below that on the optics module 2 attachable focusing module 13 can be a replaceable powder nozzle 15 be attached. An exemplary embodiment of the powder nozzle 15 is in 6A and 6B shown. The powder nozzle 15 points like the focusing module 13 fastener 16 on, by means of appropriate recordings 12 on the optics module 2 can be attached. As a fastener 16 For example, several clamping bolts on the powder nozzle 15 be arranged. Such clamping bolts are similarly used for mounting tools in conventional machine tools. The pictures 12 on the optics module 2 These clamping bolts can be used to attach the powder nozzle 15 Clamp via a hydraulic, pneumatic, electromagnetic or tensioned by a spring mechanism, so that the powder nozzle 15 detachable on the optics module 2 is attached, wherein within a specified tolerance always the same position of the powder nozzle 15 can be achieved.

In the 2 and 6 illustrated powder nozzle 15 has the top of the optical module 2 facing the end of a flange 15a on to which the fasteners 16 , For example, two clamping bolts are arranged. At the flange 15a is a substantially cylindrical central portion of the powder nozzle 15 arranged. At the lower end of the middle section is a substantially conical powder nozzle tip 15b arranged. The middle section of the powder nozzle 15 can work together with the flange 15a serve advantageously as a carrier with supplies for coolant and powder material, where the powder nozzle tip 15b can be releasably attached. Thus, a change of the powder nozzle tip 15b be enabled.

At the flange 15a the powder nozzle 15 are connections 15f . 15g or interfaces for supplying a coolant or a material powder arranged. The connections 15f for the coolant, for example, be designed as quick couplings, which are located when attaching the powder nozzle 15 on the optics module 2 automatically with corresponding lines on the optics module 2 connect. The inlets 15g for the material powder may be formed as simple openings, which have a sealing ring. When attaching the powder nozzle 15 on the optics module 2 The inlets are pressed with the sealing rings to corresponding outlets on the optical module such that a gas-tight connection is formed.

The inlets 15g for material powder stand each with channels 15d for the material powder passing through the powder nozzle 15 to the top 15b the powder nozzle 15 run in fluid communication. In the top 15b the powder nozzle 15 is an annular gap 15c formed, the gap width can taper in the flow direction to achieve a nozzle effect. The transition between material powder channels 15d and annular gap 15c is shaped such that a circumferentially uniform distribution of the material powder is produced. For example, it may be a plurality of holes in a transition from the material powder channels 15d to the annular gap 15c be provided. The holes can be a uniform distribution of the material powder P in the annular gap 15c cause. The stream of material powder P may be in the form of a cone aligned coaxially with the focal point of the laser beam, as shown by the illustration of FIG 7 indicated.

The powder nozzle tip 15b can be detachable at the powder nozzle 15 be attached so that it can be replaced by heat, for example, in case of damage or deformation. In a multi-part construction of the powder nozzle 15 can the powder nozzle tip 15b also from a different, more heat-resistant and / or harder material than the rest of the powder nozzle 15 be made. Differently sized powder nozzle tips 15b For example, they can be used for different laser beam diameters. Furthermore, differently sized annular gaps 15c with different opening widths in exchangeable powder nozzle tips 15b be educated. Accordingly, also different powder nozzles 15 with differently sized powder nozzle tips 15b in the machine 1 be kept so that if necessary, the entire powder nozzle 15 can be exchanged. The diameter of the lower facing the workpiece Opening of the powder nozzle tip 15b may for example be 1 mm, 2 mm, 3 mm, 4 mm or 5 to 8 mm. The replacement of the powder nozzle tips 15b is preferably done manually, while changing the entire powder nozzle 15 as described below can be done fully automatically.

The powder nozzle 15 has at least two couplings 15f for coolant, which are preferably designed as quick couplings. A clutch 15f serves as a connection for the flow of the coolant from the optics module 2 that other clutch 15f serves as a connection for the return of the coolant to the optics module 2 , The connections 15f for coolant are in fluid communication with coolant channels 15e in the powder nozzle 15 in the partially sectioned view of the 6A are illustrated. The coolant channels 15e For example, they may be annular, spiral or helical around the laser beam aperture to provide uniform cooling of the powder nozzle 15 to ensure.

Inside the flange 15a is a substantially cylindrical recess for the focusing module 13 formed. When the focusing module 13 and the powder nozzle 15 on the optics module 2 are fixed, is the lower end of the focusing module 13 inside the recess in the powder nozzle 15 , Here are the focusing module 13 and the powder nozzle 15 coaxial with each other and with the laser beam on the optics module 2 arranged.

The powder nozzle 15 indicates due to the plurality of channels for coolant 15e and channels for material powder 15d , as well as with its axial opening tapering in the axial direction to the laser focal point on a very complex shape. Such a complex shape can be achieved, for example, by a laser deposition welding method in a machine according to the invention 1 getting produced. To the manufacturing process of the powder nozzle 15 can be performed by laser deposition welding in as little time and with the greatest possible savings of material, for example, the substantially cylindrical central portion of the powder nozzle 15 be built with the thinnest possible wall thickness. To the mechanical strength of the powder nozzle 15 To increase, the wall can through slats 15l be strengthened. Similarly, the transition between flange 15a and middle section of the powder nozzle 15 be made material-saving by, for example, as in 6B illustrated honeycomb structure 15w is used, which offers high mechanical strength with low material consumption.

The flange 15a and the middle section of the powder nozzle 15 may be made of aluminum or steel, for example. The diameter of the flange 15a may be about 150 mm to 170 mm, preferably 160 mm. The entire length of the powder nozzle 15 may be about 125 mm to 145 mm, preferably 135 mm. When using focusing optics 14 with shorter focal lengths and correspondingly shorter powder nozzles can be used with less than 125 mm, for example, 100 mm to 90 mm in length. Be focusing optics 14 used with higher focal lengths, correspondingly longer powder nozzles with more than 145 mm, for example 150 mm to 200 mm or even 300 mm in length can be used. The diameter of the central portion of the powder nozzle may be about 60 mm to 70 mm, preferably 65 to 67 mm. Preferably, the powder nozzle 15 even more compact designed to reduce the risk of collisions with the workpiece 30 to reduce.

Replacing the powder nozzle 15 can be done for example as described below. The partition between the process chamber 22 and the tool chamber arranged laterally thereof is pushed. By means of the adjusting axle 25b becomes the lower part of the tool changer 25 with the powder nozzles 15 in the process chamber 22 hazards. The adjusting axles 18 move the optics module 2 to the position where tool changer 25 with the multitude of powder nozzles 15 located. To place one on the optics module 2 attached powder nozzle 15 must be different than in 4 and 5 illustrated a storage position of the tool changer 25 be free. By opening the recordings 12 on the optics module 2 become the fasteners 16 the powder nozzle 15 released, leaving the powder nozzle 15 from the optics module 2 is released and at a free storage position of the tool changer 25 can be stored.

Then the optics module 2 to another position of the tool changer 25 procedure, at which a further powder nozzle 15 having a larger or smaller dimension in the axial direction is located. The optics module 2 is then by means of adjusting axles 18 moves, leaving the fasteners 16 the further powder nozzle 15 in the recordings 12 on the optics module 2 intervention. By closing the recordings 12 can the powder nozzle 15 on the optics module 2 attached and from the tool changer 25 be taken out.

The automatic change of the powder nozzle 15 can take place in particular if, by a change of the focusing optics 14 the focal length of the laser beam is changed. Because the powder nozzle 15 the material powder is to lead to the location of the focal point of the laser beam, the axial length of the powder nozzle 15 be selected according to the focal length of the laser beam. As listed in Table 1, the focal length of the focusing optics 14 For example, be 200 mm or 300 mm. Accordingly, in the tool changer 25 the machine 1 corresponding powder nozzles 15 be held, the material powder to an example, 200 mm or 300 mm from the focusing optics 14 lead away from the focus.

Over the powder nozzle 15 can be a material powder at the working point of the machine 1 , ie in the immediate vicinity of the focal point of the laser beam. For this purpose, the powder nozzle 15 a channel or more channels over which the material powder is passed. When attaching the powder nozzle 15 on the optics module 2 is a compound of the channels for the material powder with appropriate lines in the optical module 2 produced. For connecting the channels and the lines have the powder nozzle 15 or the optics module 2 each suitable interfaces. Furthermore, the powder nozzle has 15 a cooling channel or a plurality of cooling channels, in which a fluid coolant, in particular water, for cooling the powder nozzle 15 can circulate. The optics module 2 has corresponding lines for supplying and discharging the coolant and interfaces for connecting the lines with the cooling channels of the powder nozzle 15 on.

Furthermore, the powder nozzle 15 a protective gas to the working point of the machine 1 conduct, so that when melting the material powder in the focal point of the laser beam undesirable reactions can be largely suppressed. The protective gas serves in particular to displace oxygen from the air. In particular, inert gases such as argon can be used as protective gas. For supplying the protective gas, the optical module 2 corresponding lines. The protective gas can also be supplied together with the material powder as a carrier gas. Thus, the inert gas serves on the one hand to prevent a reaction with atmospheric oxygen and on the other hand to convey the material powder.

When automatically replacing the powder nozzle 15 become the cooling pipes of the optics module 2 with the cooling channels of the powder nozzle 15 automatically connected or disconnected via the corresponding interfaces. Accordingly, the lines for material powder in the optics module 2 with the material powder channels in the powder nozzle 15 automatically connected or disconnected via the corresponding interfaces. The corresponding interfaces for the lines and channels can be designed to be releasable and, for example, each be controlled via a hydraulic or pneumatic.

An automatic change of the focusing module 13 can be done in a similar way as the automatic change of the powder nozzle 15 , This is done by means of the adjusting axis 25a also the upper part of the tool changer 25 with the focusing modules 13 in the process chamber 22 hazards. To change the focusing module 13 However, one must first on the optical module 2 attached powder nozzle 15 be solved. This is done as described above by the powder nozzle 15 at a free storage position of the tool changer 25 is filed. The adjusting axles 18 then move the optics module 2 to a position where the tool changer 25 with the variety of focusing modules 13 located. The at the optics module 2 fixed focusing module 13 can by opening the shots 11 on the optics module 2 be released, leaving the focusing module 13 from the optics module 2 dissolved and at a free storage position of the tool changer 25 can be stored. The following is another focussing module 13 on the optics module 2 be attached. This is the optics module 2 so proceed, so that the fasteners 16 of the focusing module 13 in the recordings 11 on the optics module 2 intervention. The pictures 11 on the optics module 2 can now use the fasteners 16 For example, use a hydraulic, pneumatic, or spring-loaded mechanism to clamp the focusing module 13 on the optics module 2 to fix. Subsequently, the tool changer 25 moved back into the detachable tool chamber and the processing of the workpiece started or continued.

The required travel paths of the positioning axes 18 . 25a . 25b can be stored in a memory of the machine control, so that changing the focusing module 13 or the powder nozzle 15 can be carried out fully automatically. The change of the focusing module 13 or the powder nozzle 15 can thus also be integrated into a machining process. Depending on the desired size of the structures of the workpiece to be produced 30 or the molding 30 a suitable diameter of the laser beam at the focal point is chosen. The smaller the diameter of the laser beam at the focal point, the smaller the structures can be made. The diameter of the laser beam determines the focal length of the focusing optics, as shown in Table 1 14 as well as the collimation optics 3 , For each machining operation can thus be a suitable combination of collimation optics 4 and focusing optics 14 to get voted. Depending on the chosen collimation optics 4 and focusing optics 14 in turn becomes a suitable powder nozzle 15 chosen and on the optics module 2 attached. On the one hand, the opening of the powder nozzle tip 15b be big enough so that the laser beam L can happen unhindered. On the other hand, the opening of the powder nozzle tip 15b be small enough to have a cheap and steady flow of water Material powder P through the annular gap 15c to the focal point of the laser beam L to effect. Accordingly, a suitable Kollimationsoptik corresponding to the selected structure size 4 at the collimation optics changer 3 as well as a suitable focusing module 13 and a corresponding powder nozzle 15 on the optics module 2 attached.

The first deflecting mirror 6 has means for cooling and monitoring the temperature of the mirror 6 on. The second deflection mirror 7 is a dichroic mirror that also provides means for cooling and monitoring the temperature of the mirror 7 having. For the wavelength of the laser beam, which is for example in the infrared spectral range, is the dichroic mirror 7 reflective. For visible light, however, the dichroic mirror may be permeable. Behind the dichroic mirror 7 can a camera 9 be arranged to monitor the manufacturing process. The camera 9 is viewed along the laser beam through the dichroic mirror and through the focusing optics 14 arranged on the focal point of the laser beam. Thus, with the camera 9 the working point on the workpiece or the molded body to be manufactured are monitored.

The optics module 2 has interfaces for receiving control signals from a machine controller. For example, the control signals may cause the collimating optical changer 3 performs a Kollimationsoptikwechsel. Furthermore, the measured temperatures of the collimating optics can be transmitted via the interfaces 4 , the deflecting mirror 6 . 7 or the other optical components are transmitted to the machine control.

The operating principle of laser deposition welding is based on the 7 illustrated. 7 shows the tip 30 a powder nozzle 15 near a workpiece to be machined W , A focused laser beam L runs coaxially to the powder nozzle 15 and is at an operating point on the workpiece W focused. The material powder P becomes coaxial to the laser beam L through the powder nozzle 15 to the focal point of the laser beam L on the workpiece W directed. A protective or carrier gas G also flows through the powder nozzle 15 and transports the material powder P , The protective gas G , For example, argon, also serves to undesirable reactions of the heated material powder P or the workpiece W to prevent with atmospheric oxygen.

The features disclosed in the foregoing description, the claims and the drawings may be of importance both individually and in any combination for the realization of the invention in its various forms.

LIST OF REFERENCE NUMBERS

1

Laser machine tool

2

optical module

3

Kollimationsoptikwechsler

4

collimating optics

6

first deflecting mirror

7

second deflecting mirror (dichroic mirror)

8th

casing

9

camera

10

fiber coupler

11

Interface for focusing optics

12

Interface for powder nozzle

13

focusing module

13a

thermocouple

13b

Interface of the thermocouple

14

focusing optics

14a

protective glass

15

powder nozzle

15a

Pulverdüsenflansch

15b

Powder nozzle tip

15c

annular gap

15d

Material powder channel

15e

cooling channel

15f

Coolant clutch

15g

Material powder inlet

15l

slats

15w

honeycomb structure

16

clamping bolt

17

Beam path of the laser

18

Setting axes of the tool

19

Setting axes of the workpiece table

20

Worktable

21

machine frame

22

process chamber

23

Process chamber door

24

display

25

tool changer

25a

Adjusting axis of the focusing optics changer

25b

Adjusting axis of the powder nozzle changer

30

workpiece

L

laser beam

W

workpiece

P

Workpiece powder

G

Protective gas and / or carrier gas

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102015222689 A1 [0003]
• EP 2052845 A2
• DE 102013224649 A1 [0003]
• DE 19630147 A1 [0003]
• US 2017/0136578 A1 [0005]
• EP 2062679 A1 [0006]

Claims (10)

Focusing module (13) for a machine (1) for machining workpieces and / or for producing shaped bodies by means of site-selective solidification of material powder into contiguous areas by means of a laser beam, comprising: a substantially cylindrical support housing; a focusing optics (14); and Fastening means (16) for releasably securing the focusing module (13) to a laser processing head (2) of the machine (1). Focusing module (13) after Claim 1 , wherein the fastening means (16) have at least two clamping bolts. Focusing module (13) after Claim 1 or 2 wherein the focusing module (13) comprises means for cooling the focusing optics (14). Focusing module (13) according to one of the preceding claims, wherein the focusing module (13) has means for measuring the temperature of the focusing optics (14). Focusing module (13) according to one of the preceding claims, wherein the focusing module (13) comprises at least one protective glass (14a) for protecting the focusing optics (14) against contamination. Focusing module (13) after Claim 5 wherein the focusing module (13) comprises means (13a) for measuring the temperature of the at least one protective glass (14a). Focusing module (13) after Claim 4 and / or 6, wherein the focusing module (13) has at least one interface (13b) for transmitting a measured temperature signal from the means (13a) for measuring the temperature of the focusing optics and / or the at least one protective glass (14a) to the machine (1) , Focusing module (13) according to one of the preceding claims, wherein the focusing optics (14) is positioned in the carrier housing in the axial direction as a function of its focal length. Focusing module (13) according to one of the preceding claims, wherein the focusing optics (14) is releasably secured in the focusing module (13). Machine (1) for machining workpieces and / or for producing shaped bodies by means of site-selective solidification of material powder to coherent areas by means of a laser beam, characterized in that the machine is a focusing module (13) according to at least one of Claims 1 to 9 having.

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