Scanner system for use in device for producing three-dimensional workpieces

Abstract

The invention relates to a scanner system (10) for use in an apparatus (100) for producing a three-dimensional workpiece by applying electromagnetic radiation or particle radiation to a layer of a raw material powder, the scanner system (10) comprising a pivotable scanner mirror (12) having a first surface (14) configured to be impinged by an irradiation beam (116) emitted by a radiation source (114). Furthermore, the scanner system (10) includes a scanner mirror cooling device (22) having a first coolant supply device (26) configured to direct a first coolant flow (28) over the first surface (14) of the scanner mirror (12), and / or directing a first coolant flow onto a first surface of the scanner mirror.

Description

Technical Field

[0001] This invention relates to a scanner system used in an apparatus for producing three-dimensional workpieces using a generative layer construction process. The invention also relates to a method of operating such a scanner system, and an apparatus equipped with such a scanner system for producing three-dimensional workpieces using a generative layer construction process. Background Technology

[0002] In generative layer construction processes for producing three-dimensional workpieces, particularly in so-called powder bed fusion, raw material powder is applied layer by layer onto a carrier, and the powder is selectively irradiated with electromagnetic radiation (e.g., laser radiation or particle radiation) according to the desired geometry of the workpiece to be produced. The radiation penetrating into the powder layer causes heating, resulting in the melting or sintering of the powder particles. Subsequently, additional layers of raw material powder are continuously applied onto the irradiated layers on the substrate until the workpiece has the desired shape and size. The raw material powder may include ceramics, metals, or plastic materials, but may also include mixtures of these materials. For example, generative layer construction methods, particularly powder bed fusion, can be used to produce prototypes, tools, spare parts, or medical prostheses (e.g., dental or orthopedic prostheses), as well as CAD-based repair components.

[0003] For example, a system for producing three-dimensional workpieces by selectively irradiating raw material powder, as known from EP 2 335 848 B1, includes a processing chamber sealed relative to the surrounding atmosphere and a carrier arranged within the processing chamber to receive the raw material powder to be irradiated. The system also includes an irradiation device and an optical unit, the irradiation device being equipped with a radiation source, particularly a laser source. The optical unit is used to selectively guide the irradiation beam generated by the radiation source onto the raw material powder layer applied to the carrier, according to the geometry of the workpiece to be produced. For this purpose, the optical unit typically includes a beam expander and a scanner system. Diffractive optical elements can be arranged in the scanner system, which can be inserted into the beam path to split the irradiation beam fed to the scanner system into multiple partial beams. Furthermore, the scanner system includes a pivotable mirror for guiding the irradiation beam incident on the mirror to a desired position on the powder bed. Finally, the irradiation beam emitted by the scanner system is guided to an objective lens, which may be designed, for example, in the form of an F-θ lens.

[0004] When constructing a three-dimensional workpiece by selectively irradiating a powder layer applied to a carrier, the radiant energy introduced into the raw powder causes the powder particles to melt and / or sinter. Typically, a molten pool of the raw powder forms in the region of the point of impact of the irradiation beam on the raw powder layer. Due to the thermal radiation emitted from the irradiated powder bed, the temperature of the processing chamber and optical unit typically rises during workpiece construction. Furthermore, the pivotable mirrors of the scanner system experience temperature rise due to the direct irradiation of the irradiation beam, which is deflected by a mirror.

[0005] As described in EP 3 067 132 A1, temperature variations in an optical unit can cause specific optical properties of the optical elements within the unit to change due to temperature. For example, the refractive index or geometry of the optical elements may change depending on the temperature of the optical elements. This can cause a shift in the focal position of the irradiation beam emitted onto the feed powder layer.

[0006] To limit the temperature rise of the optical unit due to thermal radiation emitted from the irradiated powder bed, WO2022 / 096304 A1 proposes arranging absorbing and reflecting elements in the processing chamber and / or optical unit. Furthermore, WO2022 / 096304 A1 describes cooling channels integrated into the walls of the processing chamber, the optical unit, and the absorbing elements. Summary of the Invention

[0007] The present invention aims to provide a scanner system that can be used in an apparatus for producing high-quality three-dimensional workpieces using a generative layer construction process. Furthermore, the present invention aims to provide a method for operating such a scanner system, and an apparatus equipped with such a scanner system for producing three-dimensional workpieces using a generative layer construction process.

[0008] This objective is achieved by a scanner system having the features of claim 1, a method for operating the scanner system having the features of claim 13, and an apparatus having the features of claim 18 for producing three-dimensional workpieces using a generative layer construction process.

[0009] A scanner system suitable for use in an apparatus for producing three-dimensional workpieces by irradiating a layer of raw material powder with electromagnetic radiation or particle radiation is disclosed. The scanner system includes at least one pivotable scanner mirror. During operation of the scanner system, the scanner mirror is used to deflect an irradiation beam (particularly a laser beam) emitted by a radiation source, such that the beam strikes the raw material powder layer applied to a carrier of the apparatus for producing the three-dimensional workpiece at a desired location. The scanner mirror includes a first surface configured to be irradiated by the irradiation beam emitted by the radiation source. For example, the first surface of the scanner mirror may be the front side of the scanner mirror facing the radiation source. The first surface of the scanner mirror is preferably designed as a reflective surface.

[0010] During operation of the scanner system, the scanner mirror is exposed to thermal radiation emitted from the irradiated powder bed. Furthermore, the scanner mirror is heated by an irradiation beam incident on a first surface of the scanner mirror. Therefore, the scanner system includes a scanner mirror cooling device having a first coolant supply device configured to direct a first coolant flow above the first surface of the scanner mirror, and / or to direct a first coolant flow onto the first surface of the scanner mirror. This allows the heat energy introduced into the first surface of the scanner mirror by the irradiation beam to dissipate directly at the point of introduction (i.e., at the point where the irradiation beam incident on the scanner mirror). This allows for particularly effective cooling of the scanner mirror, especially of the first surface of the scanner mirror subjected to particularly high thermal stress. This particularly reduces the thermally induced displacement of the focal position of the irradiation beam guided onto the raw powder layer in the xy irradiation plane.

[0011] Therefore, scanner systems are particularly advantageous for use in apparatuses for producing three-dimensional workpieces, where a layer of raw powder is irradiated by high-power and / or multiple irradiation beams. Especially in multi-laser systems, effective cooling of the scanner mirror enables improved multi-laser alignment, thereby enabling the production of high-quality workpieces.

[0012] In principle, a scanner system may include only one scanner mirror. However, it is also conceivable that a scanner system may include two or more pivotable scanner mirrors. Two scanner mirrors can be used to deflect the processing beam along the x and y directions. If the scanner system includes two pivotable scanner mirrors, each scanner mirror may be designed as described herein, i.e., including a first surface configured to be irradiated by an illumination beam emitted from a radiation source and cooled by a first coolant flow directed onto and / or onto the first surface of the scanner mirror. A separate scanner mirror cooling device and / or a separate first coolant supply device may be assigned to each scanner mirror. However, the scanner mirror cooling device and / or the first coolant supply device may also be configured to direct a first coolant flow or multiple first coolant flows onto and / or onto the first surfaces of multiple scanner mirrors. Furthermore, each or some of existing scanner mirrors may have the features discussed below.

[0013] The first coolant supply device is preferably configured to guide a first coolant flow relative to a first surface at an angle of approximately 0° to approximately 30°, preferably approximately 0° to approximately 25°, and particularly preferably approximately 0° to approximately 20°, onto the first surface of the scanner mirror, and / or to guide the first coolant flow relative to the first surface at an angle of approximately 0° to approximately 30°, preferably approximately 0° to approximately 25°, and particularly preferably approximately 0° to approximately 20°, onto the first surface of the scanner mirror. Flowing onto the first surface of the scanner mirror at a "flat" angle allows the first coolant flow to pass uniformly across the first surface of the scanner mirror. The result is low turbulence in the first coolant flow and a corresponding small change in refractive index. Furthermore, dust particles can be guided onto and removed from the first surface of the scanner mirror, preventing the transfer of dust particles from one optical element of the scanner system to another. The first coolant supply device may, for example, include an outlet opening arranged and aligned in such a way that the first coolant flow impacts the first surface of the scanner mirror at the desired "flat" angle.

[0014] In a particularly preferred embodiment of the scanner system, the scanner mirror cooling device further includes a second coolant supply device configured to direct a second coolant flow onto a second surface of the scanner mirror opposite to the first surface, and / or to direct a second coolant flow onto the second surface of the scanner mirror opposite to the first surface. The second surface of the scanner mirror may, for example, be the rear surface of the scanner mirror, which is not directly irradiated by an illumination beam emitted by a radiation source and is away from the radiation source. If the scanner system includes two or more pivotable scanner mirrors, the second coolant supply device may be associated with each scanner mirror. However, the second coolant supply device may also be configured to direct a second coolant flow or multiple second coolant flows onto a plurality of second surfaces of the scanner mirrors, and / or to direct a second coolant flow or multiple second coolant flows onto a plurality of second surfaces of the scanner mirrors.

[0015] Cooling both the first and second surfaces of the scanner mirror results in uniform cooling of the scanner mirror. This prevents or at least reduces temperature fluctuations of the scanner mirror over time and temperature gradients within the scanner mirror. Therefore, thermally induced deformation of the scanner mirror and the resulting effects on its optical properties are avoided. Furthermore, cooling both the first and second surfaces of the scanner mirror allows for the dissipation of a greater amount of heat energy from the scanner mirror. Therefore, equipping the scanner mirror cooling system with both a first and a second coolant supply is particularly advantageous when the scanner mirror is exposed to particularly high thermal loads, such as when the scanner system is used in a multi-laser system, and / or when using a radiation source to generate and emit an illumination beam with a particularly high power level (which creates high intensity on the surface of the scanner mirror).

[0016] Cooling fins can be provided in a region of the second surface of the scanner mirror. For example, the second surface of the scanner mirror can be partially or completely covered by cooling fins. This enables particularly good heat dissipation from the scanner mirror and thus particularly effective cooling of the scanner mirror.

[0017] The second coolant supply device is preferably configured to guide a second coolant flow relative to the second surface at an angle of approximately 40° to approximately 90°, preferably approximately 45° to approximately 90°, and particularly preferably approximately 50° to approximately 90°, onto the second surface of the scanner mirror, and / or to guide the second coolant flow relative to the second surface at an angle of approximately 40° to approximately 90°, preferably approximately 45° to approximately 90°, and particularly preferably approximately 50° to approximately 90°, onto the second surface of the scanner mirror. To achieve this, the second coolant supply device may, for example, include a first outlet opening arranged and aligned such that the second coolant flow impacts the second surface of the scanner mirror at a desired “steep” angle.

[0018] Additionally or alternatively, the second coolant supply device may also be configured to guide the second coolant flow relative to the second surface at an angle of approximately 0° to approximately 30°, preferably approximately 0° to approximately 25°, and particularly preferably approximately 0° to approximately 20°, onto the second surface of the scanner mirror, and / or guide the second coolant flow relative to the second surface at an angle of approximately 0° to approximately 30°, preferably approximately 0° to approximately 25°, and particularly preferably approximately 0° to approximately 20°, onto the second surface of the scanner mirror. Thus, similar to the first coolant supply device, the second coolant supply device may also provide a flow into the second surface of the scanner mirror at a "flat" angle. For this purpose, the second coolant supply device may include a second outlet opening arranged and aligned such that the second coolant flow impacts the second surface of the scanner mirror at the desired "flat" angle.

[0019] The first and second coolant supply devices can be configured to guide the first and second coolant flows at equal angles relative to the first and second surfaces, respectively, above and / or onto the first and second surfaces of the scanner mirror, in such a way that any torques acting on the scanner mirror caused by the coolant flows cancel each other out. For example, the first and second coolant supply devices can be arranged symmetrically relative to the first and second surfaces of the scanner mirror, such that the first and second coolant flows are guided at equal angles relative to the first and second surfaces, respectively, above and / or onto the first and second surfaces of the scanner mirror.

[0020] Preferably, the first coolant supply device is configured to direct a first coolant flow onto a first surface of the scanner mirror, and / or to direct a first coolant flow onto the first surface of the scanner mirror, wherein the first coolant flow is adjustable in terms of volumetric flow rate and / or flow velocity. Additionally or alternatively, the second coolant supply device may be configured to direct a second coolant flow onto a second surface of the scanner mirror, and / or to direct a second coolant flow onto the second surface of the scanner mirror, wherein the second coolant flow is adjustable in terms of flow rate and / or flow velocity. Specifically, the first and second coolant supply devices may be configured to deliver coolant flows having independently adjustable volumetric flow rates and / or flow velocities. Corresponding control of the volumetric flow rates and / or flow velocities of the coolant flows delivered by the first and second coolant supply devices can then be used to ensure that the torque acting on the scanner mirror cancels out or at least reduces each other at different, asymmetric angles of attack of the coolant flows relative to the first and second surfaces of the scanner mirror, respectively.

[0021] The second coolant supply device may include a first coolant supply element facing the second surface of the scanner mirror. Furthermore, the first coolant supply element may be arranged at an angle of approximately 70° to approximately 110° relative to the second surface of the scanner mirror, preferably approximately 80° to 100°, and particularly preferably approximately 90°. Specifically, the longitudinal axis of the first coolant supply element may be arranged at an angle of approximately 70° to approximately 110° relative to the second surface of the scanner mirror, preferably approximately 80° to 100°, and particularly preferably approximately 90°. This allows the inflow onto the second surface of the scanner mirror to be achieved at a “steep” angle.

[0022] Furthermore, the second coolant supply device may include a second coolant supply element arranged at an angle of approximately 0° to approximately 30° relative to the second surface of the scanner mirror, preferably at an angle of approximately 0° to approximately 25°, and particularly preferably at an angle of approximately 0° to approximately 20°. Specifically, the longitudinal axis of the first coolant supply element may be arranged at an angle of approximately 0° to approximately 30° relative to the second surface of the scanner mirror, preferably at an angle of approximately 0° to approximately 25°, and particularly preferably at an angle of approximately 0° to approximately 20°. This allows the inflow of coolant onto the second surface of the scanner mirror to be achieved at a "flat" angle.

[0023] The first coolant supply device can be designed, for example, in the form of a nozzle. Additionally or alternatively, the first and / or second coolant supply elements of the second coolant supply device can be designed in the form of nozzles. One or more of these nozzles can be designed as dual-jet nozzles or T-shaped elements to improve the accessibility of the coolant and the nozzles to the scanner mirror to be cooled, respectively. Furthermore, the first and / or second coolant supply devices, particularly the first and / or second coolant supply elements of the second coolant supply device, can be movably designed and configured to move according to the movement of the scanner mirror. This ensures optimal cooling of the scanner mirror at all locations.

[0024] The first coolant supply device and the second coolant supply device may be at least partially integral with each other. In particular, the second coolant supply element of the second coolant supply device may be integrated into the first coolant supply device. Then, the first coolant supply device is not only configured to guide the first coolant flow above the first surface of the scanner mirror, and / or to guide the first coolant flow onto the first surface of the scanner mirror, but is also equipped with a second coolant supply element associated with the second coolant supply device, which is further configured to guide the second coolant flow above the second surface of the scanner mirror, and / or to guide the second coolant flow onto the second surface of the scanner mirror.

[0025] The first coolant supply device is preferably arranged at an angle of approximately 0° to approximately 30° relative to the first surface of the scanner mirror. Specifically, the longitudinal axis of the first coolant supply device may be arranged at an angle of approximately 0° to approximately 30° relative to the first surface of the scanner mirror. This allows the inflow onto the first surface of the scanner mirror to be achieved particularly well at the desired "flat" angle. Additionally or alternatively, the first coolant supply device may be arranged offset relative to the scanner mirror along the pivot axis of the scanner mirror. In other words, when viewed along the pivot axis of the scanner mirror, the first coolant supply device may be arranged "in front of" or "behind" the scanner mirror. This ensures that the illumination beam directed towards the first surface of the scanner mirror is not blocked by the first coolant supply device.

[0026] The scanner mirror can be connected to a drive device via a drive shaft extending along the pivot axis of the scanner mirror, the drive device being designed, for example, in the form of a galvanometer motor. A first coolant supply device can be arranged on the side of the scanner mirror facing away from the drive device; that is, when viewed along the pivot axis, the first coolant supply device is arranged "behind" the scanner mirror. However, alternatively, it is conceivable to arrange the first coolant supply device on the side of the scanner mirror facing the drive device. Then, when viewed along the pivot axis, the first coolant supply device is arranged "in front" of the scanner mirror.

[0027] As described above, the first coolant supply device may be arranged at an angle greater than 0° (e.g., about 20°) relative to the first surface of the scanner mirror. However, the first coolant supply device may also be arranged at an angle of about 0° relative to the first surface of the scanner mirror. In particular, the first coolant supply device may be arranged coaxially or parallel to the longitudinal axis of the drive shaft, and / or integrated into the drive shaft. The first coolant supply device then provides a first coolant flow that flows over the first surface of the scanner mirror at an angle of about 0° (i.e., parallel to the first surface). The first coolant supply device is then particularly well-suited for integration with a second coolant supply element of a second coolant supply device. In particular, the first coolant supply device may then include a second coolant supply element of the second coolant supply device, which provides a second coolant flow that flows over the second surface of the scanner mirror at an angle of about 0° (i.e., parallel to the second surface).

[0028] Preferably, the first coolant supply device is configured to guide the first coolant flow symmetrically above the first surface relative to the pivot axis of the scanner mirror, and / or to guide the first coolant flow symmetrically onto the first surface relative to the pivot axis of the scanner mirror, in such a way that substantially no torque is exerted on the scanner mirror due to the first coolant. This prevents undesirable deflection of the scanner mirror caused by the first coolant flow. For example, the outlet opening of the first coolant supply device can be arranged and aligned such that the first coolant flow symmetrically impacts the first surface of the scanner mirror relative to the pivot axis of the scanner mirror.

[0029] Additionally or alternatively, the second coolant supply device may be configured to symmetrically guide the second coolant flow onto the second surface relative to the pivot axis of the scanner mirror, and / or symmetrically guide the second coolant flow onto the second surface relative to the pivot axis of the scanner mirror, in such a way that substantially no torque is exerted on the scanner mirror due to the second coolant flow. This prevents undesirable deflection of the scanner mirror caused by the second coolant flow. For example, in the second coolant supply device, the first outlet opening and / or the second outlet opening of the second coolant supply device may be arranged and aligned in such a way that the second coolant flow symmetrically impacts the second surface of the scanner mirror relative to the pivot axis of the scanner mirror.

[0030] The first and / or second coolant streams preferably contain / comprise gases, such as purified air or inert gases, such as helium, argon, nitrogen, or gas mixtures. Helium is particularly suitable as an inert cooling gas because it has high thermal conductivity and thus dissipates heat effectively. When helium is used as the cooling gas, the first and / or second coolant streams can be achieved at small volumetric flow rates, as even small coolant volumetric flow rates are sufficient to cool the first and / or second surfaces of the scanner mirror as desired. When using only small coolant volumetric flow rates, the scanner system or the scanner housing of the scanner system should be sealed as well as possible to keep coolant loss to a minimum.

[0031] In a preferred embodiment, the scanner system further includes a cooling system for cooling the internal space of the housing housing the scanner system. Then, in addition to the scanner mirror cooling device, the scanner system is equipped with an "advanced" cooling system that cools all components located within the housing. The cooling system may be configured to supply a gaseous coolant, particularly an inert gas such as helium, to the housing housing the scanner system.

[0032] In principle, the cooling system can be designed such that the housing containing the scanner system is continuously flushed with coolant, with the coolant guided into the housing via a coolant supply line and removed from the housing via a coolant discharge line. However, the cooling system preferably includes recirculation lines connected to the coolant inlet and outlet of the housing, allowing the coolant to circulate through the housing. In a closed loop sealed relative to the environment, no further contamination from the environment and / or from the continuously supplied coolant is expected. This means less contaminant is introduced into the housing compared to continuous flushing with coolant. A heat exchanger may be arranged in the recirculation line to cool the coolant before it returns to the housing. Furthermore, a filter may be arranged in the recirculation line to remove dirt particles, oil, and / or moisture from the coolant circulating in the loop.

[0033] However, a cooling system equipped with a recirculation line may also include a coolant supply line, which may be connected to the recirculation line or the housing. New or additional coolant can then be supplied to or replenished to the closed loop via the coolant supply line. This, for example, makes it possible to replace coolant lost due to leaks in the housing or other components of the cooling system.

[0034] Variations in the coolant flow supplied to the housing can cause pressure fluctuations within the housing. These pressure fluctuations can lead to vibrations, expansion, displacement, etc., of the housing and / or scanner mirrors, which can reduce the scanner's positioning accuracy. Therefore, a check valve can be installed in the coolant supply line or recirculation line, in the area of ​​the housing's coolant outlet, i.e., downstream of the coolant outlet. Preferably, the check valve is configured to allow gas to escape from the housing into the environment when the pressure in the housing exceeds its activation pressure. This prevents or at least significantly reduces undesirable pressure fluctuations in the housing.

[0035] Preferably, the check valve is also configured to prevent gas from entering the housing. Specifically, the check valve is configured to prevent gas from entering the housing even when a negative pressure exists within the housing (i.e., a pressure below ambient pressure). This prevents potentially contaminated air from entering the housing from the environment.

[0036] The scanner mirror cooling device and the "advanced" cooling system can be designed separately. However, it is also conceivable to partially or completely integrate the scanner mirror cooling device into the cooling system. For example, the coolant supply line and / or recirculation line of the cooling system can also supply coolant to the scanner mirror cooling device. The scanner mirror cooling device and the cooling system then share a common coolant supply line and / or recirculation line. Coolant flowing through the coolant supply line and / or recirculation line can be directed into the housing containing the scanner system through a single coolant inlet. Then, within the housing, the coolant can be directed to the desired location or components to be cooled, such as mirrors, lenses, mounts, cooling elements, etc., through several outlet openings of the coolant supply line and / or recirculation line. However, it is also conceivable to direct coolant flowing through the coolant supply line and / or recirculation line into the housing containing the scanner system through several coolant inlets.

[0037] Preferably, the scanner system further includes at least one flow control device configured to enable or at least support controlled removal of coolant supplied by a first coolant supply device and / or a second coolant supply device and / or a "higher" cooling system from the vicinity of the component to be cooled (e.g., a scanner mirror). The at least one flow control device prevents coolant heated by heat transferred from the component to be cooled from coming into thermal contact with another component to be cooled. In other words, regardless of whether the coolant is supplied by the first coolant supply device, the second coolant supply device, or the "higher" cooling system, at least one flow generation device prevents multiple components to be cooled from being continuously submerged in the same coolant flow and prevents heated coolant from remaining between the components to be cooled.

[0038] For example, at least one flow control device may include at least one flow guiding element (e.g., a baffle or shielding element) and / or at least one coolant guiding channel. Furthermore, the flow control device may be movable. For example, the flow control device may be movable in such a way that the position and / or orientation of the flow control device can be adjusted as desired according to the position of the scanner reflector.

[0039] Optionally, at least one flow control device may be designed such that other optical components (e.g., lenses, protective glass, or deflectors) disposed in and / or on the housing are also exposed to the coolant flow. Furthermore, the flow control device is advantageously designed in such a way that it prevents the coolant, which has been heated by heat transferred from the component to be cooled, from coming into thermal contact with another component to be cooled. This allows for the establishment of a uniform temperature distribution on the optical components.

[0040] A cooling fin structure disposed in a region of the second surface of the scanner mirror can serve as a flow control device. The cooling fins can then be designed as flow guiding elements that direct the coolant flow impacting the second surface of the scanner mirror in a desired direction. For example, the cooling fins can guide the coolant flow in such a way that other components or cooling elements located in and / or on the housing are also impacted by the coolant flow. However, additionally or alternatively, the cooling fins can also be designed such that, after the coolant flow has passed the second surface of the scanner mirror, the coolant flow is guided through other (optical) components or towards the inner wall of the housing to prevent several components to be cooled from being continuously submerged by the same coolant flow.

[0041] The control unit of the scanner system controls the operation of the first coolant supply device and / or the second coolant supply device and / or the "advanced" cooling system, particularly controlling the volumetric flow rate and / or velocity of the first coolant flow, the second coolant flow, and / or the coolant flow provided by the "advanced" cooling system. Preferably, the control unit of the scanner system is configured to consider control parameters related to the state of the entire system when controlling the individual coolant flows. Such relevant control parameters may be, for example, temperature, particularly temperature distribution, or pressure, especially pressure distribution within the housing of the scanner system.

[0042] For example, the control unit can be configured to evaluate signals transmitted by corresponding temperature and / or pressure sensors and use these signals as control parameters for controlling the individual coolant flows. The temperature and / or pressure sensors can measure the temperature and / or pressure throughout the housing housing the scanner system, or detect localized temperature and / or pressure values ​​present at specific locations within the housing. Furthermore, one or more temperature sensors can be provided to detect the temperature of one or more coolant flows and transmit corresponding signals to the control unit, which can then take these signals into account when controlling the coolant flows. Additionally, the control unit can be configured to use analog values ​​of the relevant control parameters and heat transfer within the housing housing the scanner system at all relevant locations (i.e., setting angles) of the scanner mirror when controlling the coolant flows.

[0043] Furthermore, the control unit of the scanner system can be configured to monitor the cleanliness of the coolant supplied by a first coolant supply device and / or a second coolant supply device and / or an "advanced" cooling system. To this end, the control unit can evaluate signals from a particle counter and / or check the cleanliness of an optical reference surface exposed to the monitored coolant flow to prevent contamination. For example, a diffuse light sensor can be used for this purpose.

[0044] A method for operating a scanner system used in an apparatus for producing a three-dimensional workpiece by irradiating a layer of raw material powder with electromagnetic radiation or particle radiation, wherein an irradiation beam emitted by a radiation source is used to irradiate a first surface of at least one pivotable scanner mirror. A first coolant supply device of a scanner mirror cooling device directs a first coolant flow above the first surface of the scanner mirror and / or directs a first coolant flow onto the first surface of the scanner mirror.

[0045] The first coolant supply device preferably directs the first coolant flow relative to the first surface at an angle of about 0° to about 30°, preferably at an angle of about 0° to about 25°, particularly preferably at an angle of about 0° to about 20°, onto the first surface of the scanner mirror, and / or directs the first coolant flow relative to the first surface at an angle of about 0° to about 30°, preferably at an angle of about 0° to about 25°, particularly preferably at an angle of about 0° to about 20°, onto the first surface of the scanner mirror.

[0046] In addition, the second coolant flow can be directed to the second surface of the scanner mirror opposite to the first surface by the second coolant supply device of the scanner mirror cooling device, and / or the second coolant flow can be directed to the second surface of the scanner mirror opposite to the first surface.

[0047] The second coolant supply device guides the second coolant flow relative to the second surface at an angle of approximately 40° to approximately 90°, preferably approximately 45° to approximately 90°, and particularly preferably approximately 50° to approximately 90°, onto the second surface of the scanner mirror, and / or guides the second coolant flow relative to the second surface at an angle of approximately 40° to approximately 90°, preferably approximately 45° to approximately 90°, and particularly preferably approximately 50° to approximately 90°, onto the second surface of the scanner mirror. Alternatively or additionally, the second coolant supply device may guide the second coolant flow relative to the second surface at an angle of approximately 0° to approximately 30°, preferably approximately 0° to approximately 25°, and particularly preferably approximately 0° to approximately 20°, onto the second surface of the scanner mirror, and / or guide the second coolant flow relative to the second surface at an angle of approximately 0° to approximately 30°, preferably approximately 0° to approximately 25°, and particularly preferably approximately 0° to approximately 20°, onto the second surface of the scanner mirror.

[0048] Preferably, the first coolant supply device symmetrically guides the first coolant flow onto the first surface relative to the pivot axis of the scanner mirror, and / or symmetrically guides the first coolant flow onto the first surface relative to the pivot axis of the scanner mirror, in such a way that substantially no torque is exerted on the scanner mirror due to the first coolant flow. Furthermore, the second coolant supply device may also symmetrically guide the second coolant flow onto the second surface relative to the pivot axis of the scanner mirror, and / or symmetrically guide the second coolant flow onto the second surface relative to the pivot axis of the scanner mirror, in such a way that substantially no torque is exerted on the scanner mirror due to the second coolant flow.

[0049] Furthermore, the method of operating the scanner system may have all the features described above in conjunction with the scanner system.

[0050] An apparatus for producing three-dimensional workpieces by irradiating a layer of raw material powder with electromagnetic radiation or particle radiation is disclosed. The apparatus includes a scanner system as described above. Furthermore, the apparatus may include a processing chamber and a carrier, the processing chamber being particularly sealed relative to the surrounding atmosphere, and the carrier for receiving the raw material powder to be irradiated. The carrier may be arranged within the processing chamber. However, it is also conceivable that the processing chamber may be movable above the carrier. The carrier may be a rigidly fixed carrier. However, preferably, the carrier may be movable vertically, such that as the height of the workpiece stacked on the carrier increases, the carrier may gradually move downwards vertically. The raw material powder applied to the carrier is preferably a metal powder, particularly a metal alloy powder. However, the raw material powder may also be a ceramic powder or a powder containing various materials. The powder may have any suitable particle size or particle size distribution. However, it is preferred to process powders with a particle size less than 100 μm.

[0051] Preferably, the apparatus further includes an irradiation device for guiding electromagnetic radiation or particle radiation onto a powder bed applied to a carrier in a point-selective manner. Preferably, the aforementioned scanner system forms part of the irradiation device. In addition to the scanner system, the irradiation device preferably includes a radiation source, particularly a laser source. Furthermore, besides the scanner system, the irradiation device may also include additional optical elements for guiding and / or processing the irradiation beam provided by the radiation source. Preferably, the beam emitted by the scanner system is guided by an objective lens of the irradiation device, which may be designed, in particular, as an F-θ lens. Attached Figure Description

[0052] Preferred embodiments of the invention will now be explained in more detail with reference to the accompanying schematic diagrams, in which: Figure 1A first embodiment of an apparatus for producing three-dimensional workpieces by irradiating a layer of raw material powder with electromagnetic radiation or particle radiation is shown, the apparatus being equipped with a scanner system. Figure 2 It shows Figure 1 Detailed views of the first embodiment of the scanner system shown. Figure 3 A detailed view of a second embodiment of the scanner system is shown. Figure 4 A detailed view of a third embodiment of the scanner system is shown. Figure 5 Detailed views of a fourth embodiment of the scanner system are shown, and Figure 6 A detailed view of the fifth embodiment of the scanner system is shown. Detailed Implementation

[0053] like Figure 1 The apparatus 100 shown for producing a three-dimensional workpiece by irradiating a layer of raw material powder with electromagnetic radiation or particle radiation includes a processing chamber 102 that is sealed relative to the surrounding atmosphere. A powder application device 104 arranged in the processing chamber 102 is used to apply the raw material powder layer onto a carrier 106. The carrier 106 is movable in a vertical direction such that as the height of the workpiece 108 constructed on the carrier 106 increases, the carrier 106 can be progressively moved downward in a construction chamber 109 in a vertical direction.

[0054] The processing chamber 102 is provided with a gas inlet 110 for supplying an inert gas (e.g., argon) into the processing chamber 102. A gas outlet 112 is also provided to generate a continuous airflow through the processing chamber 102. The airflow can be used to remove molten spatter and / or other unwanted contaminant particles, such as welding fumes, from the processing chamber 102.

[0055] The apparatus 100 also includes an irradiation device 112 for guiding electromagnetic radiation or particle radiation onto a powder bed applied to a carrier 106 in a point-selective manner. Figure 1 The exemplary device 100 shown includes only one irradiation device 112. However, the device 100 may also include multiple irradiation devices 112.

[0056] The irradiation device 112 includes a radiation source 114, which is specifically formed in the form of a laser source. The radiation source 114 may include, for example, a diode-pumped ytterbium fiber laser emitting laser light with a wavelength of approximately 1070 nm to 1080 nm, and the radiation source 114 may be integrated into the irradiation device 112. However, in Figure 1In the apparatus 100 shown, a radiation source 114 is arranged outside the irradiation device 112, wherein a laser beam 116 emitted by the radiation source 114 is guided into the irradiation device 112 via an optical fiber 118.

[0057] The illumination unit 112 also includes two lenses 120 and 122. Figure 1 In the embodiment of the illumination unit 112 shown, both lenses 120 and 122 have positive refractive power. Lens 120 collimates the laser emitted from fiber 118 to produce a collimated or substantially collimated laser beam 116. On the other hand, lens 122 is configured to focus the collimated (or substantially collimated) laser beam 116 at a desired z-position along the z-axis.

[0058] Finally, the irradiation unit 112 includes a scanner system 10 having a scanner mirror 12 pivotable about a pivot axis S. During operation of the device 100, the scanner system 10, and in particular the scanner mirror 12, is used to deflect a laser beam 116 emitted by the radiation source 114, so that the beam 116 strikes the raw material powder layer applied to the carrier 106 at a desired location.

[0059] The scanner mirror 12 includes a first surface 14, which is irradiated by a laser beam 116 emitted by a radiation source 114 during operation of the device 100. Specifically, the first surface 14 of the scanner mirror 12 is the front side of the scanner mirror 12 facing the radiation source 114. The first surface 14 of the scanner mirror 12 is designed as a reflective surface. Furthermore, the scanner mirror 12 includes a second surface 16 opposite to the first surface 14. Specifically, the second surface 16 of the scanner mirror 12 is the rear side of the scanner mirror 12 away from the radiation source 114, and therefore is not directly irradiated by the laser beam 116 emitted by the radiation source 114. The second surface 16 of the scanner mirror 12 is provided with cooling fins 17.

[0060] The scanner mirror 12 is connected to the drive device 20 via a drive shaft 18 extending along the pivot axis S of the scanner mirror 12. The drive device 20 is, for example, in the form of a galvanometer motor. During operation of the device 100, the drive device 20 is controlled by the control unit (not in...). Figure 1 Under the control of the scanner reflector 12 (shown in the figure), the scanner reflector 12 guides the laser beam 116 onto the raw material powder layer on the carrier 106 in a point-selection manner according to the geometry of the workpiece 108 to be produced and according to the desired irradiation pattern.

[0061] When the laser beam 116 strikes the raw material powder layer on the carrier 116, the radiant energy introduced into the raw material powder causes the powder particles to melt and / or sinter. During operation of the device 100, components of the irradiation system 112 are exposed to thermal radiation emitted from the irradiated powder bed. The scanner mirror 12 of the scanner system 10 is also heated by the laser beam 116 striking the first surface 14 of the scanner mirror 12. To counteract the temperature-induced changes in the optical properties of the scanner mirror 12 and the resulting shift in the focal position of the laser beam 116 in the xy irradiation plane extending parallel to the surface of the carrier 106, the scanner system 10 includes a scanner mirror cooling device 22. Figure 1 The text is only schematically indicated and can be referenced below. Figures 2 to 6 A more detailed description is provided. Furthermore, the scanner system 10 includes a cooling system 24, which also... Figure 1 The above is only an illustrative indication and will be explained in more detail below.

[0062] If possible Figures 2 to 4 As seen, the scanner mirror cooling device 22 includes a first coolant supply device 26, which is configured to: direct a first coolant flow 28 over the first surface 14 of the scanner mirror 12, and / or direct a first coolant flow 28 onto the first surface 14 of the scanner mirror 12. Figure 2 In a first embodiment of the scanner system 10 shown, a first coolant supply device 26, designed, for example, in the form of a nozzle, is configured to guide a first coolant flow 28 at an angle of approximately 10° to approximately 20° above the first surface 14 of the scanner mirror 12, and / or to guide the first coolant flow 28 at an angle of approximately 10° to approximately 20° above the first surface 14 of the scanner mirror 12.

[0063] Therefore, the first coolant supply device 26 is arranged at an angle of approximately 15° relative to the first surface 14 of the scanner mirror 12, that is, the longitudinal axis of the first coolant supply device 26 forms an angle of approximately 15° with the first surface 14 of the scanner mirror 12. Therefore, the outlet opening of the first coolant supply device 26 (not in...) Figure 1 (As shown in detail) This allows the coolant to flow into the first surface 14 of the scanner mirror 12 at an angle of approximately 10° to approximately 20°. The first coolant flow 28 directly and effectively dissipates the heat energy introduced into the first surface 14 of the scanner mirror 12 by the laser beam 116 at the point of introduction.

[0064] The first coolant supply device 26 is arranged on the side of the scanner mirror 12 facing away from the drive device 20, that is, when viewed from the drive device 20 along the pivot axis S, the first coolant supply device 26 is arranged "behind" the scanner mirror 12. This ensures that the laser beam 116 pointing towards the first surface 14 of the scanner mirror 12 is not blocked by the first coolant supply device 26.

[0065] Furthermore, the first coolant supply device 26 is configured to guide the first coolant flow 28 symmetrically relative to the pivot axis S of the scanner mirror 12 over the first surface 14 of the scanner mirror 12, and / or to guide the first coolant flow 28 symmetrically relative to the pivot axis S of the scanner mirror 12 onto the first surface 14 of the scanner mirror 12, in such a way that substantially no torque is exerted on the scanner mirror 12 due to the first coolant flow 28. To ensure this, the outlet opening of the first coolant supply device 26 is arranged and aligned such that the first coolant flow 28 impacts the first surface 14 of the scanner mirror 12 symmetrically relative to the pivot axis S of the scanner mirror 12. This prevents undesirable deflection of the scanner mirror 12 about the pivot axis S caused by the first coolant flow 28 impacting the first surface 14 of the scanner mirror 12.

[0066] Furthermore, the scanner mirror cooling device 22 includes a second coolant supply device 30, which is configured to direct a second coolant flow 32 over, and / or direct the second coolant flow 32 onto, the second surface 16 of the scanner mirror 12 opposite to the first surface 14. Figure 2 In a first embodiment of the scanner system 10 shown, the second coolant supply device 30 is configured to guide a second coolant flow 32 at an angle of approximately 55° to approximately 90° above the second surface 16 of the scanner mirror 12, and / or to guide the second coolant flow 32 at an angle of approximately 55° to approximately 90° above the second surface 16 of the scanner mirror 12.

[0067] To achieve this, the second coolant supply device 30 includes a first coolant supply element 34, which is, for example, in the form of a nozzle, facing the second surface 14 of the scanner mirror 12. The first coolant supply element 34 is arranged at an angle of approximately 90° relative to the second surface 16 of the scanner mirror 12; that is, the longitudinal axis of the first coolant supply element 34 of the second coolant supply device 30 forms an angle of approximately 90° with the second surface 16 of the scanner mirror 12. Therefore, the first outlet opening of the first coolant supply element 34 (not in...) Figure 1 (As shown in detail) allows the coolant to flow at an angle of approximately 55° to approximately 90° onto the second surface 16 of the scanner mirror 12. Cooling both the first surface 14 and the second surface 16 of the scanner mirror 12 enables uniform cooling of the scanner mirror, thereby avoiding or at least reducing temperature fluctuations of the scanner mirror over time and temperature gradients within the scanner mirror 12.

[0068] Similar to the first coolant supply device 26, the second coolant supply device 30, that is, in Figure 1 In the illustrated scanner system 10, the first coolant supply element 34 is also configured to guide the second coolant flow 32 symmetrically relative to the pivot axis S of the scanner mirror 12 over the second surface 16 of the scanner mirror 12, and / or to guide the second coolant flow 32 symmetrically relative to the pivot axis S of the scanner mirror 12 onto the second surface 16 of the scanner mirror 12, in such a way that substantially no torque is applied to the scanner mirror 12 due to the second coolant flow 32. To ensure this, the outlet opening of the first coolant supply element 34 of the second coolant supply device 30 is arranged and aligned such that the second coolant flow 32 impacts the second surface 16 of the scanner mirror 12 symmetrically relative to the pivot axis S of the scanner mirror 12. This prevents undesirable deflection of the scanner mirror 12 about the pivot axis S caused by the second coolant flow 32 impacting the second surface 16 of the scanner mirror 12.

[0069] The first coolant stream 28 and / or the second coolant stream 32 contain / comprise gases, such as purified air or inert gases. Helium is particularly suitable as an inert cooling gas because it has high thermal conductivity and therefore can effectively dissipate heat.

[0070] The cooling system 24 is ultimately used to cool the internal space of the housing 36 that houses the scanner system 10. Therefore, in addition to the scanner mirror cooling device 22 which provides target localized cooling for the scanner mirror 12, the scanner system 10 is also equipped with an "advanced" cooling system 24 that cools all components located within the housing 36. The housing 36 may be a scanner housing that only houses the components of the scanner system 10. However, alternatively, the housing 36 may also house additional or all components of the irradiation device 112.

[0071] Cooling system 24 supplies gaseous coolant from coolant source 38 to the interior space of housing 36. The gaseous coolant is, in particular, an inert gas, such as helium. Coolant inlet 40 of housing 36 is connected to coolant outlet 44 of housing 36 via recirculation line 42, allowing coolant to circulate through housing 36. Coolant supply line 45 connects coolant source 38 to recirculation line 42. Therefore, less contaminant is introduced into housing 36 compared to continuous flushing with coolant. Heat exchanger 46 is arranged in recirculation line 42, cooling the coolant before it returns to housing 36. Furthermore, [the following text is incomplete and likely refers to a separate process:] ...not in Figure 1 The filter shown can be installed in the recirculation line 42 to remove contaminants from the coolant before it returns to the housing 36. For example, it can be... Figure 1 As can be seen best, the recirculation line 42 supplies coolant not only to the cooling system 24, but also to the scanner mirror cooling device 22.

[0072] In the recirculation line 42, a check valve 47 is provided in the region of the coolant outlet 44, i.e., downstream of the coolant outlet 44. The check valve 47 is configured to allow gas to escape from the housing 36 into the environment when the pressure in the housing 36 exceeds its activation pressure. Furthermore, the check valve 47 is configured to prevent gas from entering the housing 36 even if a negative pressure lower than ambient pressure exists within the housing 36. The check valve 47 reduces or prevents pressure fluctuations in the housing 36.

[0073] The cooling fin structure disposed in the region of the second surface 16 of the scanner mirror 12 serves as a flow control device. Specifically, each cooling fin 17 serves as a flow guiding element, guiding the coolant flow 32 in a desired direction after it has flowed onto the second surface 16 of the scanner mirror 12. For example, the cooling fin 17 can guide the coolant flow 32 in such a way that, after the coolant flow has flowed onto the second surface 16 of the scanner mirror 12, it is guided past other (optical) components disposed in the housing 32. In addition to the cooling fins 17, further flow control devices and / or flow guiding elements (not shown) may be provided to ensure the desired direction of the coolant flows 28, 32 and the coolant flows guided by the cooling system 24 into and through the housing 36.

[0074] Figure 3 The second embodiment of the scanner system 10 shown is based on... Figure 2The difference in arrangement is that, viewed from the drive device 20 along the pivot axis S, the first coolant supply device 26 is not located on the side of the scanner reflector 12 facing away from the drive device 20, but rather on the side facing the drive device 20. In other words, according to Figure 3 In this arrangement, viewed from the drive device 20 along the pivot axis S, the first coolant supply device 26 is not positioned "behind" the scanner mirror, but rather "in front" of it, adjacent to the drive device 20. This also ensures that the laser beam 116 striking the first surface 14 of the scanner mirror 12 is not blocked by the first coolant supply device 26. Furthermore, Figure 3 The structure and operating mode of the scanner system 10 shown correspond to those according to... Figure 2 The layout structure and operation mode.

[0075] exist Figure 4 In the third embodiment of the scanner system 10 shown, the first coolant supply device 26 is arranged at an angle of approximately 0° relative to the first surface 14 of the scanner mirror 12, that is, coaxially with the longitudinal axis of the drive shaft 18. The outlet opening of the first coolant supply device 26 (not shown in...) Figure 4 (As shown in detail) Facing the scanner reflector 12, the first coolant supply device 26 provides a first coolant flow 28, which flows over the first surface 14 of the scanner reflector 12 at an angle of approximately 0°, i.e. parallel to the first surface 14 and substantially parallel to the drive shaft 18.

[0076] In addition, Figure 4 In the scanner system 10 shown, the first coolant supply device 26 and the second coolant supply device 30 are at least partially integrally formed with each other. In particular, the second coolant supply element 48 of the second coolant supply device 30 is integrally formed with the first coolant supply device 26, such that the first coolant supply device 26 and the second coolant supply element 48 of the second coolant supply device 30 form a "showerhead nozzle".

[0077] The second coolant supply element 48 of the second coolant supply device 30 is arranged at an angle of approximately 0° relative to the second surface 16 of the scanner reflector 12, that is, coaxially with the longitudinal axis of the drive shaft 18, wherein the outlet opening of the second coolant supply element 48 (not in) Figure 4 (As shown in detail) Facing the scanner reflector 12. As a result, the second coolant supply element 48 of the second coolant supply device 30 provides a second coolant flow 32, which flows over the second surface 16 of the scanner reflector 12 at an angle of approximately 0°, i.e., parallel to the second surface 16 and substantially parallel to the drive shaft 18.

[0078] Viewed from the drive device 20 along the pivot axis S, the second coolant supply elements 48 of the first coolant supply device 26 and the second coolant supply device 30 are arranged on the side of the scanner mirror 12 facing away from the drive device 20; that is, when viewed from the drive device 20 along the pivot axis S, the first coolant supply device 26 and the second coolant supply elements 48 of the second coolant supply device 30 are arranged "behind" the scanner mirror. This ensures that the laser beam 116 impacting the first surface 14 of the scanner mirror 12 is not blocked. Furthermore, Figure 4 The structure and operating mode of the scanner system 10 shown correspond to those according to... Figure 2 and Figure 3 The layout structure and operation mode.

[0079] exist Figure 4 In the scanner system 10 shown, the following is omitted: Figure 1 and Figure 2 The first coolant supply element 34 of the second coolant supply device 30 shown. However, it is conceivable to supply according to Figure 4 The scanner system 10 is additionally equipped with a first coolant supply element 34 or an additional first coolant supply device 26 of a second coolant supply device 30.

[0080] Figure 5 The fourth embodiment of the scanner system 10 shown is in accordance with... Figure 4 The difference in arrangement is that, viewed from the drive device 20 along the pivot axis S, the second coolant supply element 48 of the first coolant supply device 26 and the second coolant supply device 30 (the second coolant supply element 48 is integrally formed with the first coolant supply device 26) is not located on the side of the scanner mirror 12 away from the drive device 20, but rather on the side facing the drive device 20 within the region of the drive device 20. However, the second coolant supply element 48 of the first coolant supply device 26 and the second coolant supply device 30 (the second coolant supply element 48 is integrally formed with the first coolant supply device 26) is still arranged at an angle of approximately 0° relative to the first surface 14 and the second surface 16 of the scanner mirror 12, that is, coaxially with the longitudinal axis of the drive shaft 18.

[0081] Furthermore, there exists that have been combined Figure 2 and Figure 3The first coolant supply element 34 of the described second coolant supply device 30 is arranged at an angle of approximately 90° relative to the second surface 16 of the scanner mirror 12 and guides a first component 32a of the second coolant flow 32 above the second surface 16 of the scanner mirror 12 at an angle of approximately 55° to approximately 90° relative to the second surface 16, and / or guides the first component 32a of the second coolant flow 32 to the second surface 16 of the scanner mirror 12 at an angle of approximately 55° to approximately 90° relative to the second surface 16.

[0082] The outlet 50 of the first coolant supply device 26 is directed toward the first surface 14 of the scanner mirror 12, and directs the first cooling airflow 28 toward the first surface 14 at an angle of approximately 0° to approximately 10°, and / or directs the first cooling airflow 28 toward the first surface 14 at an angle of approximately 0° to approximately 10°. Similarly, the outlet 52 of the second coolant supply element 48 of the second coolant supply device 30 is directed toward the second surface 16 of the scanner mirror 12, and directs the second component 32b of the second cooling airflow 32 toward the second surface 16 at an angle of approximately 0° to approximately 10°, and / or directs the second component 32b of the second cooling airflow 32 toward the second surface 16 at an angle of approximately 0° to approximately 10°. In addition, Figure 5 The structure and operating mode of the scanner system 10 shown correspond to those according to... Figures 2 to 4 The layout structure and operation mode.

[0083] Figure 6 The fifth embodiment of the scanner system 10 shown is in accordance with... Figure 5 The difference in arrangement lies in that the second coolant supply element 48 of the first coolant supply device 26 and the second coolant supply device 30 (the second coolant supply element 48 is integrally formed with the first coolant supply device 26) is integrated into the drive shaft 18. In addition, Figure 6 The structure and operating mode of the scanner system 10 shown correspond to those according to... Figure 5 The layout structure and operation mode.

Claims

1. A scanner system (10) used in an apparatus (100) for producing a three-dimensional workpiece by irradiating a layer of raw material powder with electromagnetic radiation or particle radiation, wherein, The scanner system (10) includes: - At least one pivotable scanner mirror (12) having a first surface (14) configured to be irradiated by an illumination beam (116) emitted from a radiation source (114); and - A scanner mirror cooling device (22) having a first coolant supply device (26) configured to direct a first coolant flow (28) above a first surface (14) of the scanner mirror (12) and / or direct the first coolant flow (28) onto the first surface (14) of the scanner mirror (12).

2. The scanner system (10) according to claim 1, wherein, The first coolant supply device (26) is configured to direct the first coolant flow (28) relative to the first surface (14) at an angle of about 0° to about 30°, preferably at an angle of about 0° to about 25°, particularly preferably at an angle of about 0° to about 20°, over the first surface (14) of the scanner mirror (12), and / or to direct the first coolant flow (28) relative to the first surface (14) at an angle of about 0° to about 30°, preferably at an angle of about 0° to about 25°, particularly preferably at an angle of about 0° to about 20°, over the first surface (14) of the scanner mirror (12).

3. The scanner system (10) according to claim 1 or 2, wherein, The scanner mirror cooling device (22) further includes a second coolant supply device (30) configured to direct a second coolant flow (32) over a second surface (16) of the scanner mirror (12) opposite to the first surface (14), and / or direct the second coolant flow (32) onto the second surface (16) of the scanner mirror (12) opposite to the first surface (14).

4. The scanner system (10) according to claim 3, wherein: - The second coolant supply device (30) is configured to guide the second coolant flow (32) relative to the second surface (16) at an angle of approximately 40° to approximately 90°, preferably approximately 45° to approximately 90°, particularly preferably approximately 50° to approximately 90°, above the second surface (16) of the scanner mirror (12), and / or to guide the second coolant flow (32) relative to the second surface (16) at an angle of approximately 40° to approximately 90°, preferably approximately 45° to approximately 90°, particularly preferably approximately 50° to approximately 90°, above the second surface (16) of the scanner mirror (12); and / or - The second coolant supply device (30) is configured to guide the second coolant flow (32) relative to the second surface (16) at an angle of about 0° to about 30°, preferably at an angle of about 0° to about 25°, particularly preferably at an angle of about 0° to about 20°, above the second surface (16) of the scanner mirror (12), and / or guide the second coolant flow (32) relative to the second surface (16) at an angle of about 0° to about 30°, preferably at an angle of about 0° to about 25°, particularly preferably at an angle of about 0° to about 20°, above the second surface (16) of the scanner mirror (12).

5. The scanner system (10) according to claim 3 or 4, wherein, The second coolant supply device (30) includes a first coolant supply element (34) facing the second surface (16) of the scanner mirror (12) and arranged at an angle of about 70° to about 110°, preferably about 80° to 100°, and particularly preferably about 90° relative to the second surface (16) of the scanner mirror (12).

6. The scanner system (10) according to any one of claims 3 to 5, wherein, The second coolant supply device (30) includes a second coolant supply element (48) arranged at an angle of about 0° to about 30° relative to the second surface (16) of the scanner mirror (12), preferably at an angle of about 0° to about 25°, and particularly preferably at an angle of about 0° to about 20°.

7. The scanner system (10) according to any one of claims 3 to 6, wherein, The first coolant supply device and the second coolant supply device (26, 30) are at least partially integral with each other.

8. The scanner system (10) according to any one of claims 1 to 7, wherein: - The first coolant supply device (26) is arranged at an angle of about 0° to about 30° relative to the first surface (14) of the scanner mirror (12), and / or offset relative to the scanner mirror (12) along the pivot axis (S) of the scanner mirror (12).

9. The scanner system (10) according to any one of claims 1 to 8, wherein, The scanner mirror (12) is connected to the drive device (20) via a drive shaft (18) extending along the pivot axis (S) of the scanner mirror (12), and wherein: - The first coolant supply device (26) is arranged on the side of the scanner reflector (12) facing away from the drive device (20) or on the side of the scanner reflector facing the drive unit (20), and / or - The first coolant supply device (26) is arranged coaxially or parallel to the longitudinal axis of the drive shaft (18), and / or the first coolant supply device is integrated into the drive shaft (18).

10. The scanner system (10) according to any one of claims 1 to 9, wherein: - The first coolant supply device (26) is configured to symmetrically guide the first coolant flow (28) relative to the pivot axis (S) of the scanner mirror (12) above the first surface (14), and / or symmetrically guide the first coolant flow (28) relative to the pivot axis (S) of the scanner mirror (12) onto the first surface (14), in such a way that substantially no torque is applied to the scanner mirror (12) due to the first coolant flow (28); and / or - The second coolant supply device (30) is configured to guide the second coolant flow (32) symmetrically over the second surface (16) relative to the pivot axis (S) of the scanner mirror (12), and / or to guide the second coolant flow (32) symmetrically over the second surface (16) relative to the pivot axis (S) of the scanner mirror (12), in such a way that substantially no torque is applied to the scanner mirror (12) due to the second coolant flow (32).

11. The scanner system (10) according to any one of claims 1 to 10, wherein, The first coolant stream (28) and / or the second coolant stream (32) contain / comprise purified air or an inert gas, particularly helium, argon, nitrogen, or a mixture of gases.

12. The scanner system (10) according to any one of claims 1 to 11, further comprising: A cooling system (24) for cooling the interior space of the housing (36) housing the scanner system (10), wherein the cooling system (24) specifically includes a recirculation line (42) connected to a coolant inlet (40) and a coolant outlet (44) of the housing (36).

13. A method for operating a scanner system (10) used in an apparatus (100) for producing a three-dimensional workpiece by irradiating a layer of raw material powder with electromagnetic radiation or particle radiation, wherein, The method includes the following steps: - Irradiate the first surface (14) of at least one pivotable scanner mirror (12) using an irradiation beam (116) emitted from a radiation source (114); and - A first coolant flow (28) is directed above the first surface (14) of the scanner mirror (12) by a first coolant supply device (26) of the scanner mirror cooling device (22), and / or the first coolant flow (28) is directed onto the first surface (14) of the scanner mirror (12).

14. The method according to claim 13, wherein, The first coolant supply device (26) directs the first coolant flow (28) relative to the first surface (14) at an angle of about 0° to about 30°, preferably about 0° to about 25°, particularly preferably about 0° to about 20°, above the first surface (14) of the scanner mirror (12), and / or directs the first coolant flow (28) relative to the first surface (14) at an angle of about 0° to about 30°, preferably about 0° to about 25°, particularly preferably about 0° to about 20°, above the first surface (14) of the scanner mirror (12).

15. The method according to claim 13 or 14, further comprising the step of: - The second coolant flow (32) is directed by the second coolant supply device (30) of the scanner mirror cooling device (22) to the second surface (16) of the scanner mirror (12) opposite to the first surface (14), and / or the second coolant flow (32) is directed to the second surface (16) of the scanner mirror (12) opposite to the first surface (14).

16. The method of claim 15, wherein: - The second coolant supply device (30) directs the second coolant flow (32) relative to the second surface (16) at an angle of approximately 40° to approximately 90°, preferably approximately 45° to approximately 90°, particularly preferably approximately 50° to approximately 90°, above the second surface (16) of the scanner mirror (12), and / or directs the second coolant flow (32) relative to the second surface (16) at an angle of approximately 40° to approximately 90°, preferably approximately 45° to approximately 90°, particularly preferably approximately 50° to approximately 90°, above the second surface (16) of the scanner mirror (12); and / or - The second coolant supply device (30) directs the second coolant flow (32) relative to the second surface (16) at an angle of about 0° to about 30°, preferably at an angle of about 0° to about 25°, particularly preferably at an angle of about 0° to about 20°, onto the second surface (16) of the scanner mirror (12), and / or directs the second coolant flow (32) relative to the second surface (16) at an angle of about 0° to about 30°, preferably at an angle of about 0° to about 25°, particularly preferably at an angle of about 0° to about 20°, onto the second surface (16) of the scanner mirror (12).

17. The method according to any one of claims 13 to 16, wherein: - The first coolant supply device (26) symmetrically directs the first coolant flow (28) relative to the pivot axis (S) of the scanner mirror (12) above the first surface (14), and / or symmetrically directs the first coolant flow (28) relative to the pivot axis (S) of the scanner mirror (12) onto the first surface (14), in such a way that substantially no torque is applied to the scanner mirror (12) due to the first coolant flow (28); and / or - The second coolant supply device (30) symmetrically directs the second coolant flow (32) above the second surface (16) relative to the pivot axis (S) of the scanner mirror (12), and / or symmetrically directs the second coolant flow (32) onto the second surface (16) relative to the pivot axis (S) of the scanner mirror (12) in such a way that substantially no torque is applied to the scanner mirror (12) due to the second coolant flow (32).

18. An apparatus (100) for producing a three-dimensional workpiece by irradiating a layer of raw material powder with electromagnetic radiation or particle radiation, comprising a scanner system (10) according to any one of claims 1 to 12.

Images