Scanner system for use in 3D workpiece manufacturing equipment

Abstract

A scanner system (10) used in an apparatus (100) for manufacturing a three-dimensional workpiece by irradiating a raw material powder layer with electromagnetic radiation or particle beams, the scanner system (10) comprises at least one rotatable scanner mirror (12) having a first surface (14) configured to be irradiated by an irradiation beam (116) emitted from an irradiation source (114). The scanner system (10) further comprises a scanner mirror cooling device (22) having a first coolant feeder (26) configured to direct a first coolant flow (28) upward and / or onto the first surface (14) of the scanner mirror (12).

Description

Technical Field

[0001] The present invention relates to a scanner system used in a manufacturing apparatus for a three-dimensional workpiece using a layer structure generation process. Further, the present invention relates to an operation method of a scanner system used in a manufacturing apparatus for a three-dimensional workpiece using a layer structure generation process, and an apparatus equipped with the scanner system.

Background Art

[0002] In a layer structure generation process for manufacturing a three-dimensional workpiece, particularly in the so-called powder bed fusion method, raw material powder is applied to a carrier layer by layer and selectively irradiated by electromagnetic radiation such as laser light or particle beams according to the desired shape of the workpiece to be manufactured. The radiation that penetrates into the powder layer generates heat, resulting in melting or sintering of the particles of the raw material powder. Thereafter, additional raw material powder is continuously applied to the already irradiated layer on the substrate until the workpiece reaches the desired shape and size. The raw material powder may be a ceramic, metal, or plastic material, or a mixture of these materials. The layer structure generation method, particularly the powder bed fusion method, is used, for example, in the manufacture of prototypes, tools, spare parts, or medical prostheses such as dental or orthopedic prostheses, and equally, in the repair of parts based on CAD data.

[0003] For example, a system for manufacturing a three-dimensional workpiece by selectively irradiating raw material powder, as described in European Patent No. 2335848, comprises a processing chamber isolated from the ambient atmosphere and a carrier positioned within the processing chamber to receive the raw material powder to be irradiated. The system further comprises an irradiation device equipped with an irradiation source, particularly a laser light source, and an optical unit. The optical unit is responsible for selectively guiding the irradiation beam generated by the irradiation source to the raw material powder layer coated on the carrier, depending on the shape of the workpiece to be manufactured. For this purpose, the optical unit typically includes a beam expander and a scanner system. To split the irradiation beam supplied to the scanner system into multiple sub-beams, a diffractive optical element may be included in the scanner system and inserted in the beam path. Furthermore, the scanner system has a swiveling mirror to direct the irradiation beam incident on the mirror to a desired position in the powder bed. The irradiation beam ejected by the scanner system is finally guided to an objective lens. The objective lens may be designed, for example, in the form of an fθ lens.

[0004] When forming a three-dimensional workpiece by selectively irradiating a powder layer coated on a carrier, the radiant energy introduced into the raw material powder melts and / or sintersects the powder particles. Typically, a molten pool of raw material powder forms in the region where the irradiation beam hits the raw material powder layer. Due to thermal radiation from the irradiated powder bed, the temperature in the processing chamber and optical unit rises during workpiece manufacturing. The swivel mirrors of the scanner system also cause a temperature rise due to direct radiation from the irradiation beam, which is refracted by the mirrors.

[0005] As described in European Patent Application Publication No. 3067132, temperature changes in an optical unit can cause temperature-dependent changes in certain optical properties of the optical elements of the optical unit. For example, the refractive index or the arrangement of the optical elements may vary depending on the temperature of the optical elements. This can cause a shift in the focal point of the irradiation beam emitted onto the raw material powder layer.

[0006] To limit the temperature rise of the optical unit due to thermal radiation emitted from the irradiated powder bed, International Publication 2022 / 096304 proposes arranging absorbing and reflecting elements in the processing chamber and / or optical unit. International Publication 2022 / 096304 further describes cooling channels incorporated into the walls of the processing chamber and optical unit and into the absorbing elements. [Overview of the project]

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

[0008] This objective is addressed by a scanner system having the configuration of claim 1, a method for operating a scanner system having the configuration of claim 13, and a manufacturing apparatus for a three-dimensional workpiece using a layer structure generation process having the configuration of claim 18.

[0009] A scanner system suitable for use in an apparatus for manufacturing three-dimensional workpieces by irradiating a raw material powder layer with electromagnetic radiation or particle beams comprises at least one swivelable scanner mirror. During the operation of the scanner system, the scanner mirror serves to refract the irradiation beam, particularly a laser beam, emitted from the irradiation source so that it strikes a desired location in the raw material powder layer coated on the carrier of the apparatus for manufacturing the three-dimensional workpiece. The scanner mirror comprises a first surface configured to be irradiated by the irradiation beam emitted from the irradiation source. For example, the first surface of the scanner mirror may be the front side of the scanner mirror facing the irradiation source. Preferably, the first surface of the scanner mirror is designed as a reflective surface.

[0010] During the operation of the scanner system, the scanner mirror is exposed to thermal radiation from the irradiated powder bed. In addition, the scanner mirror is also heated by the irradiation beam incident on the first surface of the scanner mirror. Therefore, the scanner system is equipped with a scanner mirror cooling device having a first coolant feeder configured to direct a first coolant flow upward and / or onto the first surface of the scanner mirror. This allows the thermal energy introduced to the first surface of the scanner mirror by the irradiation beam to be directly dissipated at the point of introduction, i.e., the point where the irradiation beam irradiates the scanner mirror. This allows for particularly effective cooling of the scanner mirror, and especially the first surface of the scanner mirror which is subjected to particularly high thermal stress. This reduces the shift in the focal position of the irradiation beam directed towards the raw material powder layer in the xy irradiation plane, particularly caused by heat.

[0011] Therefore, scanner systems are particularly beneficial for use in equipment that manufactures three-dimensional workpieces, where the raw material powder layer is irradiated with high-power and / or multiple beams. In multi-laser systems, the multi-laser array is improved, especially by the effective cooling of the scanner mirror, enabling the manufacture of high-quality workpieces.

[0012] In principle, a scanner system may have a single scanner mirror. However, a scanner system may also have two or more swivelable scanner mirrors. Two scanner mirrors may be used to refract the processing beam in the x and y directions. When a scanner system has two swivelable scanner mirrors, each scanner mirror may be designed to have a first surface configured to be cooled by a first coolant flow that is irradiated by an irradiation beam emitted from an irradiation source and directed upward and / or onto the first surface of the scanner mirror, as described herein. Each scanner mirror may be associated with a separate scanner mirror cooler and / or a separate first coolant feeder. However, the scanner mirror cooler and / or first coolant feeder may be configured to direct one or more first coolant flows upward and / or onto the first surfaces of multiple scanner mirrors. Furthermore, each or some of existing scanner mirrors may have the features described below.

[0013] The first coolant feeder is preferably configured to direct the first coolant flow above and / or onto the first surface of the scanner mirror at an angle of about 0° to about 30°, preferably about 0° to about 25°, and particularly preferably about 0° to about 20°. The inflow at a “flat” angle onto the first surface of the scanner mirror causes the first coolant flow to flow uniformly over the first surface of the scanner mirror. This reduces turbulence and, accordingly, reduces fluctuations in the refractive index of the first coolant flow. In addition, dust particles are directed onto and removed from the first surface of the scanner mirror, thus preventing the movement of dust particles from one optical element of the scanner system to another. The first coolant feeder may include, for example, an outlet positioned and adjusted so that the first coolant flow strikes the first surface of the scanner mirror at a desired “flat” angle.

[0014] In a particularly preferred embodiment of the scanner system, the scanner mirror cooling device may further include a second coolant feeder configured to direct a second coolant flow above and / or onto the second face of the scanner mirror opposite to the first face. The second face of the scanner mirror may be, for example, the rear face of the scanner mirror, which is not directly illuminated by the illumination beam emitted by the illumination source and does not face the illumination source. If the scanner system includes two or more swivelable scanner mirrors, the second coolant feeder may be associated with each scanner mirror. However, the second coolant feeder may be configured to direct one or more second coolant flows above and / or onto the second faces of multiple scanner mirrors.

[0015] By cooling both the first and second surfaces of the scanner mirror, the scanner mirror is cooled uniformly. This suppresses or at least reduces transient temperature fluctuations and temperature gradients within the scanner mirror. As a result, thermal deformation of the scanner mirror and its impact on its optical properties are avoided. Furthermore, cooling both the first and second surfaces of the scanner mirror allows more thermal energy to be dissipated from the scanner mirror. Therefore, a scanner cooling system equipped with both a first and second coolant supply is particularly beneficial when the scanner mirror is subjected to particularly high thermal loads, such as when the scanner system is used in a multi-laser system and / or when a particularly high-power irradiation source is used to generate and emit the irradiation beam, resulting in high intensity on the surface of the scanner mirror.

[0016] Cooling fins may be provided on the second surface of the scanner mirror. For example, the second surface of the scanner mirror may be partially or entirely covered by the cooling fins. This allows for particularly good heat dissipation from the scanner mirror, and as a result, the scanner mirror can be cooled particularly effectively.

[0017] The second coolant feeder is preferably configured to direct the second coolant flow above and / or onto the second surface of the scanner mirror at an angle of about 40° to about 90°, preferably about 45° to about 90°, and particularly preferably about 50° to about 90°. For this purpose, the second coolant feeder may include, for example, a first outlet that is positioned and adjusted so that the second coolant flow strikes the second surface of the scanner mirror at a desired "steep" angle.

[0018] In addition to or instead of the above, the second coolant feeder is preferably configured to direct the second coolant flow above and / or onto the second surface of the scanner mirror at an angle of about 0° to about 30°, preferably about 0° to about 25°, and particularly preferably about 0° to about 20°. Thus, the second coolant feeder, like the first coolant feeder, can direct the coolant flow onto the second surface of the scanner mirror at a “flat” angle. For this purpose, the second coolant feeder may include a second outlet positioned and adjusted so that the second coolant flow strikes the second surface of the scanner mirror at a desired “flat” angle.

[0019] The first and second coolant suppliers may be configured to direct the first and second coolant flows at the same angle to the first and second surfaces, respectively, upward and / or onto the first and second surfaces, so that the rotational forces that may be generated on the scanner mirror due to the coolant flow cancel each other out. For example, the first and second coolant suppliers may be positioned symmetrically with respect to the first and second surfaces of the scanner mirror, respectively, so that the first and second coolant flows at the same angle to the first and second surfaces, respectively, upward and / or onto the first and second surfaces, respectively.

[0020] Preferably, the first coolant dispenser is configured to direct the first coolant flow upward and / or onto the first surface of the scanner mirror, with adjustable volumetric flow rate and / or flow velocity. In addition to or instead, preferably, the second coolant dispenser is configured to direct the second coolant flow upward and / or onto the second surface of the scanner mirror, with adjustable flow rate and / or flow velocity. In particular, the first and second coolant dispensers may be configured to deliver coolant flows with independently adjustable volumetric flow rate and / or flow velocity. The corresponding control of the volumetric flow rate and / or flow velocity of the coolant flows delivered by the first and second coolant dispensers may be used to ensure mutual cancellation or at least reduction of rotational forces that may occur on the scanner mirror due to coolant flow attacks at different, asymmetrical angles for each of the first and second surfaces of the scanner mirror.

[0021] The second coolant supply unit may include a first coolant supply unit facing the second surface of the scanner mirror. Furthermore, the first coolant supply unit may be positioned at an angle of approximately 70° to approximately 110°, preferably approximately 80° to 100°, and particularly preferably approximately 90° with respect to the second surface of the scanner mirror. In particular, the longitudinal axis of the first coolant supply unit may be positioned at an angle of approximately 70° to approximately 110°, preferably approximately 80° to 100°, and particularly preferably approximately 90° with respect to the second surface of the scanner mirror. This enables a "steep" angle of coolant flow onto the second surface of the scanner mirror.

[0022] Furthermore, the second coolant supply may include a second coolant supply section positioned at an angle of approximately 0° to approximately 30°, preferably approximately 0° to approximately 25°, and particularly preferably approximately 0° to approximately 20° with respect to the second surface of the scanner mirror. In particular, the longitudinal axis of the first coolant supply section may be positioned at an angle of approximately 0° to approximately 30°, preferably approximately 0° to approximately 25°, and particularly preferably approximately 0° to approximately 20°, with respect to the second surface of the scanner mirror. This enables a "flat" angle of coolant flow onto the second surface of the scanner mirror.

[0023] The first coolant supply may be designed, for example, in the form of a nozzle. In addition to or instead of this, the first coolant supply section and / or the second coolant supply section of the second coolant supply may be designed in the form of a nozzle. One or more of these nozzles may be designed in the form of a dual-jet nozzle or T-type to increase the accessibility of the coolant and the nozzle to the scanner mirror being cooled. Furthermore, the first coolant supply and / or the second coolant supply, and in particular the first coolant supply section and / or the second coolant supply section of the second coolant supply, may be designed and configured to operate in accordance with the movement of the scanner mirror. This allows for optimal cooling in any orientation of the scanner mirror.

[0024] The first coolant supply and the second coolant supply may be formed integrally with each other in at least part. In particular, the second coolant supply unit of the second coolant supply may be incorporated into the first coolant supply. In this case, the first coolant supply is not only configured to direct the first coolant flow upward and / or onto the first surface of the scanner mirror, but is also equipped with a second coolant supply unit associated with the second coolant supply, which is similarly configured to direct the second coolant flow upward and / or onto the second surface of the scanner mirror.

[0025] The first coolant supply is preferably positioned at an angle of approximately 0° to approximately 30° with respect to the first surface of the scanner mirror. In particular, the longitudinal axis of the first coolant supply may be positioned at an angle of approximately 0° to approximately 30° with respect to the first surface of the scanner mirror. This allows for particularly good "flat" angle inflow onto the first surface of the scanner mirror. In addition to this, or alternatively, the first coolant supply may be positioned offset from the scanner mirror along the pivot axis of the scanner mirror. In other words, the first coolant supply may be positioned "in front of" or "behind" the scanner mirror when viewed along the pivot axis of the scanner mirror. This prevents the irradiation beam directed towards the first surface of the scanner mirror from being obstructed by the first coolant supply.

[0026] The scanner mirror may be connected to a drive device designed, for example, in the form of a galvanometer motor via a drive shaft extending along the pivot axis of the scanner mirror. The first coolant supplier may be arranged on the side of the scanner mirror that does not face the drive device of the scanner mirror, that is, "behind" the scanner mirror when viewed along the pivot axis. However, alternatively, it is also conceivable to arrange the first coolant supplier on the side facing the drive device of the scanner mirror. In this case, the first coolant supplier is arranged "in front" of the scanner mirror when viewed from the pivot axis.

[0027] As described above, the first coolant supplier may be arranged at an angle greater than 0°, for example, an angle of about 20°, with respect to the first surface of the scanner mirror. However, the first coolant supplier may also be arranged at an angle of about 0° with respect to the first surface of the scanner mirror. In particular, the first coolant supplier may be arranged coaxially or parallel to the longitudinal axis of the drive shaft and / or incorporated into the drive shaft. At this time, the first coolant supplier provides a first coolant flow that flows at an angle of about 0° with respect to the first surface of the scanner mirror, that is, parallel to the first surface. Such a first coolant supplier is particularly suitable for being integrally designed with the second coolant supply part of the second coolant supplier. In particular, the first coolant supplier may include the second coolant supply part of the second coolant supplier that provides a second coolant flow that flows at an angle of about 0° with respect to the second surface of the scanner mirror, that is, parallel to the second surface.

[0028] The first coolant supplier is preferably configured such that the first coolant flow is directed symmetrically with respect to the pivot axis of the scanner mirror above and / or on the first surface so that the first coolant flow does not substantially act on the rotational force. Thereby, unintended deflection of the scanner mirror due to the first coolant flow can be prevented. For example, the discharge port of the first coolant supplier may be arranged and adjusted such that the first coolant flow hits the first surface of the scanner mirror symmetrically with respect to the pivot axis of the scanner mirror.

[0029] In addition to or instead of this, the second coolant supplier may be configured such that the second coolant flow is directed above and / or on the second surface symmetrically with respect to the pivot axis of the scanner mirror so that the second coolant flow does not substantially act on the rotational force. Thereby, the unintentional deflection of the scanner mirror due to the second coolant flow can be prevented. In the second coolant supplier, for example, the first discharge port and / or the second discharge port of the second coolant supplier may be arranged and adjusted such that the second coolant flow hits the second surface of the scanner mirror symmetrically with respect to the pivot axis of the scanner mirror.

[0030] The first coolant flow and / or the second coolant flow preferably contain a gas, such as clean air, or an inert gas such as helium, argon, nitrogen, or a mixed gas. Helium is particularly suitable as an inert cooling gas because of its high thermal conductivity and the possibility of effective dissipation. When helium is used as the cooling gas, the first coolant flow and / or the second coolant flow may be implemented with a small volume flow rate because even a low volume flow rate of the coolant is sufficient to cool the first surface and / or the second surface of the scanner mirror to a desired degree. When only a coolant with a low volume flow rate is used, the scanner system or the scanner housing of the scanner system is preferably sealed as much as possible to minimize the loss of the coolant.

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

[0032] In principle, the cooling system may be designed so that the coolant flows continuously through the enclosure housing the scanner system, directed into the enclosure via a coolant supply line and discharged from the enclosure via a coolant discharge line. However, it is preferable that the cooling system includes a recirculation line connected to the coolant inlet and outlet of the enclosure so that the coolant circulates through the enclosure. In a closed circuit sealed from the environment, further contamination from the environment and / or from the continuously supplied coolant is expected to be absent (or significantly reduced). This results in less contamination introduced into the enclosure than when the coolant is continuously flowing. A heat exchanger may be placed in the recirculation line to cool the coolant before it returns to the enclosure. Furthermore, a filter may be placed in the recirculation line to remove dust particles and / or water vapor from the coolant circulating in the circuit.

[0033] However, the cooling system installed in the recirculation line may also include a coolant supply line. The coolant supply line may be connected to the recirculation line or the housing. In this case, new or additional coolant may be supplied or replenished to the closed circuit via the coolant supply line. This can replace coolant loss caused, for example, by leakage to the housing or other components of the cooling system.

[0034] Changes in the coolant supplied to the housing can cause pressure fluctuations within the housing. Such pressure fluctuations can lead to vibration, expansion, displacement, etc., of the housing and / or scanner mirror, potentially reducing the positioning accuracy of the scanner. Therefore, a check valve may be provided in the coolant supply line or recirculation line in the coolant outlet region of the housing, i.e., downstream of the coolant outlet. The check valve is preferably configured to release gas from the housing to the environment when the pressure inside the housing exceeds the activation pressure of the check valve. This prevents or at least significantly reduces undesirable pressure fluctuations inside the housing.

[0035] Furthermore, it is preferable that the check valve be configured to prevent gas from entering the housing. The check valve is specifically configured to prevent gas from flowing into the housing even when negative pressure, i.e., a pressure lower than the ambient pressure, spreads within the housing. This prevents potentially contaminated air from entering the housing from the environment.

[0036] The scanner mirror cooler and the "higher-level" cooling system may be designed to be separate from each other. However, the scanner mirror cooler may be partially or completely integrated into the cooling system. For example, the coolant supply lines and / or recirculation lines of the cooling system may also supply coolant to the scanner mirror cooler. In this case, the scanner mirror cooler and the cooling system share common coolant supply lines and / or recirculation lines. The coolant flow through the coolant supply lines and / or recirculation lines is directed into the housing that contains the scanner system through a single coolant inlet. In this case, the coolant may be directed to desired locations or to elements to be cooled, such as mirrors, lenses, fixtures, cooling elements, etc., through several outlets in the coolant supply lines and / or recirculation lines. However, the coolant flow may also be directed into the housing that contains the scanner system through the coolant supply lines and / or recirculation lines and through several coolant inlets.

[0037] Furthermore, the scanner system preferably includes at least one flow controller configured to achieve, or at least assist in, the controlled removal of coolant supplied by a first coolant supplier and / or a second coolant supplier, and / or coolant supplied by a “higher” cooling system from the vicinity of the elements to be cooled, such as the scanner mirror. The at least one flow controller prevents coolant that has already been heated by heat transfer from the elements to be cooled from coming into thermal contact with other elements to be cooled. In other words, regardless of whether the coolant is supplied by a first coolant supplier, a second coolant supplier, or a “higher” cooling system, the at least one flow generator prevents the same coolant flow from flowing too continuously to multiple elements to be cooled, and prevents heated coolant from accumulating between the elements to be cooled.

[0038] At least one flow controller may include at least one flow guide element, such as a baffle plate or shielding element, and / or at least one coolant guide channel. Furthermore, the flow controller may be movable. For example, the flow controller may be movable so that its position and / or orientation can be adjusted as desired in accordance with the position of the scanner mirror.

[0039] At least one flow controller may be optionally designed so that other optical elements, such as lenses, protective glass, and deflection mirrors, located within and / or on the housing, are also exposed to the coolant flow. Furthermore, it is beneficial for the flow controller to be designed to prevent the coolant, which has already been heated by heat transfer from the elements being cooled, from coming into thermal contact with other elements being cooled. This makes it possible to establish a uniform heat distribution in the optical elements.

[0040] A cooling fin structure provided in the region of the second surface of the scanner mirror may act as a flow controller. In this case, the cooling fins may be designed as flow guide elements that direct the coolant flow to strike the second surface of the scanner mirror in a desired direction. For example, the cooling fins may direct the coolant flow to strike other elements or cooling elements located inside and / or on the housing. However, in addition to or instead of this, the cooling fins may be designed so that, after flowing over the second surface of the scanner mirror, the coolant flow passes over other (optical) elements or is directed towards the inner wall of the housing to prevent the same coolant flow from flowing too continuously over several elements to be cooled.

[0041] The scanner system's control unit is preferably configured to control the operation of the first coolant supply device and / or the second coolant supply device and / or the “higher” cooling system, in particular the volumetric flow rate and / or flow velocity of the coolant flows supplied to the first coolant flow, the second coolant flow and / or the “higher” cooling system, and to take into account control parameters related to the state of the overall system when controlling individual coolant flows. Such related control parameters may be, for example, the temperature, in particular the temperature distribution, or the pressure, in particular the pressure distribution, in the housing that contains the scanner system.

[0042] For example, the control unit may be configured to evaluate signals transmitted by corresponding temperature and / or pressure sensors and use them as control parameters for controlling individual coolant flows. The temperature and / or pressure sensors may measure the temperature and / or pressure of the entire housing containing the scanner system, or they may detect local temperature and / or local pressure values ​​at specific locations within the housing. Furthermore, one or more temperature sensors may detect the temperature of one or more coolant flows and transmit corresponding signals to the control unit. In this case, the control unit can take this into consideration when controlling the coolant flows. Furthermore, the control unit may be configured to use relevant control parameters and simulations of heat transfer within the housing containing the scanner system at all relevant positions (i.e., set angles) of the scanner mirror when controlling the coolant flows.

[0043] In a method of operation for a scanner system used in a device for manufacturing a three-dimensional workpiece by irradiating a raw material powder layer with electromagnetic radiation or particle beams, the first surface of at least one rotatable scanner mirror is irradiated by an irradiation beam emitted from an irradiation source. A first coolant flow is directed upward and / or onto the first surface of the scanner mirror by a first coolant supplier of a scanner mirror cooling device.

[0044] The first coolant feeder directs the first coolant flow above and / or onto the first surface of the scanner mirror at an angle of about 0° to about 30°, preferably about 0° to about 25°, and particularly preferably about 0° to about 20°.

[0045] Furthermore, the second coolant flow is directed upward and / or onto the second surface of the scanner mirror that faces the first surface, by the second coolant supplier of the scanner mirror cooling device.

[0046] The second coolant feeder directs the second coolant flow above and / or onto the second surface of the scanner mirror at an angle of about 40° to about 90°, preferably about 45° to about 90°, and particularly preferably about 50° to about 90°. In addition to or instead of this, the second coolant feeder directs the second coolant flow above and / or onto the second surface of the scanner mirror at an angle of about 0° to about 30°, preferably about 0° to about 25°, and particularly preferably about 0° to about 20°.

[0047] It is preferable that the first coolant supply is directed such that the first coolant flow is symmetrical with respect to the pivot axis of the scanner mirror and directed above and / or onto the first surface, so as to prevent substantially rotational force from acting by the first coolant flow. Furthermore, the second coolant supply may also be directed such that the second coolant flow is symmetrical with respect to the pivot axis of the scanner mirror and directed above and / or onto the second surface, so as to prevent substantially rotational force from acting by the second coolant flow.

[0048] Furthermore, the operating method of the scanner system may have all of the features described above in relation to the scanner system.

[0049] An apparatus for manufacturing a three-dimensional workpiece by irradiating a raw material powder layer with electromagnetic radiation or particle beams comprises the scanner system described above. The apparatus may further include a processing chamber, particularly one isolated from the surrounding atmosphere, and a carrier for receiving the raw material powder to be irradiated. The carrier may be located within the processing chamber. However, the processing chamber may also be movable on the carrier. The carrier may be rigidly fixed. However, it is preferable that the carrier be vertically movable so that it can be gradually lowered vertically as the height of the workpiece constructed on the carrier increases. The raw material powder applied to the carrier is preferably a metal powder, particularly a metal alloy powder. However, the raw material powder may be a ceramic powder or a powder containing various materials. The powder may have a predetermined appropriate particle size or particle size distribution. However, it is preferable to process powder with a particle size smaller than 100 μm.

[0050] The apparatus preferably also includes an irradiation device that selectively directs electromagnetic radiation or particle beams onto a powder bed coated with a carrier. The scanner system described above preferably constitutes an element of the irradiation device. In addition to the scanner system, the irradiation device preferably also includes an irradiation source, particularly a laser light source. Furthermore, in addition to the scanner system, the irradiation device may include additional optical elements for directing and / or processing the irradiation beam provided by the irradiation source. The beam emitted by the scanner system is preferably directed through the objective lens of the irradiation device. The objective lens may be designed in particular in the form of an fθ lens. [Brief explanation of the drawing]

[0051] Preferred embodiments of the present invention will be described in detail with reference to the attached schematic diagrams. [Figure 1] Figure 1 shows an apparatus equipped with a scanner system of the first embodiment, which manufactures a three-dimensional workpiece by irradiating a raw material powder layer with electromagnetic radiation or particle beams. [Figure 2] Figure 2 shows a detailed view of the scanner system of the first embodiment shown in Figure 1. [Figure 3] Figure 3 shows a detailed view of the scanner system according to the second embodiment. [Figure 4] Figure 4 shows a detailed view of the scanner system according to the third embodiment. [Figure 5] Figure 5 shows a detailed view of the scanner system according to the fourth embodiment. [Figure 6] Figure 6 shows a detailed view of the scanner system according to the fifth embodiment. [Modes for carrying out the invention]

[0052] The apparatus 100 shown in Figure 1, which manufactures a three-dimensional workpiece by irradiating a raw material powder layer with electromagnetic radiation or particle beams, includes a processing chamber 102 isolated from the surrounding atmosphere. A powder coating device 104 located in the processing chamber 102 has the function of coating a carrier 106 with raw material powder. The carrier 106 is vertically movable so that the construction chamber 109 can be lowered vertically in stages as the height of the workpiece 108 built on the carrier 106 increases.

[0053] The processing chamber 102 is provided with a gas inlet 110 for supplying an inert gas (e.g., argon) to the processing chamber 102. A gas outlet 112 is also provided so as to generate a continuous gas flow through the processing chamber 102. The gas flow has the function of removing unwanted dust particles, such as molten splatter and / or welding fumes, from the processing chamber 102.

[0054] The apparatus 100 also includes an irradiation device 112 that has the function of selectively directing electromagnetic radiation or particle beams onto a powder bed coated on a carrier 106. The typical apparatus 100 shown in Figure 1 includes a single irradiation device 112. However, the apparatus 100 may include multiple irradiation devices 112.

[0055] The irradiation device 112 includes an irradiation source 114 formed therein, particularly in the form of a laser light source. The irradiation source 114 may include, for example, a diode-pumped yttrium fiber laser that emits laser light with a wavelength of approximately 1070-1080 nm, and may be incorporated into the irradiation device 112. However, in the device 100 shown in Figure 1, the irradiation source 114 is located outside the irradiation device 112, and the laser beam 116 emitted by the irradiation source 114 is introduced into the irradiation device 112 via an optical fiber 118.

[0056] The irradiation unit 112 further comprises two lenses 120 and 122. In the embodiment of the irradiation unit 112 shown in Figure 1, both lenses 120 and 122 have positive refractive power. Lens 120 parallelizes the laser light emitted from the optical fiber 118 to form a parallel or substantially parallel laser beam 116. Lens 122, on the other hand, is configured to focus the parallel (or substantially parallel) laser beam 116 to a desired z position along the z axis.

[0057] Finally, the irradiation unit 112 includes a scanner system 10 having a scanner mirror 12 that can rotate around a pivot axis S. During the operation of the device 100, the scanner system 10, and in particular the scanner mirror 12, have the function of refracting the laser beam 116 emitted from the irradiation source 114 so that the beam 116 strikes a desired position in the raw material powder layer coated on the carrier 106.

[0058] The scanner mirror 12 is irradiated by the laser beam 116 emitted from the irradiation source 114 during the operation of the device 100. In particular, the first surface 14 of the scanner mirror 12 is the front surface of the scanner mirror 12 facing the irradiation source 114 and is designed as a reflective surface. Furthermore, the scanner mirror 12 has a second surface 16 opposite to the first surface 14. The second surface 16 of the scanner mirror 12 is the rear surface of the scanner mirror 12, which does not face the irradiation source 114, and as a result is not directly irradiated by the laser beam 116 emitted from the irradiation source 114. Cooling fins 17 are provided on the second surface 16 of the scanner mirror 12.

[0059] The scanner mirror 12 is connected to a drive unit 20, designed, for example, in the form of a galvanometer motor, via a drive shaft 18 extending along the pivot axis S of the scanner mirror 12. During operation of the apparatus 100, the drive unit 20, under the control of a control unit not shown in Figure 1, drives the scanner mirror 12 to direct the laser beam 116 onto the raw material powder layer on the carrier 106 in a part-selective manner and according to a desired irradiation pattern, depending on the shape of the workpiece 108 to be manufactured.

[0060] When the laser beam 116 strikes the raw material powder layer on the carrier 116, the irradiation energy introduced into the raw material powder causes melting and / or sintering of the powder particles. During the operation of the apparatus 100, the elements 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 of the scanner mirror 12. To counteract thermally caused 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 that extends parallel to the surface of the carrier 106, the scanner system 10 is equipped with a scanner mirror cooling device 22. The scanner mirror cooling device 22 is shown in outline in Figure 1 and will be described in detail below with reference to Figures 2-6. Furthermore, the scanner system 10 is equipped with a cooling system 24, which is also shown in outline in Figure 1 and will be described in detail below with reference to Figures 2-6.

[0061] As can be seen from Figure 2-4, the scanner mirror cooling device 22 includes a first coolant supply 26 configured to direct a first coolant flow 28 upward and / or onto the first surface 14 of the scanner mirror 12. In the first embodiment of the scanner system 10 shown in Figure 2, the first coolant supply 26 is designed, for example, in the form of a nozzle and is configured to direct the first coolant flow 28 upward and / or onto the first surface 14 of the scanner mirror 12 at an angle of about 10° to about 20° relative to the first surface 14.

[0062] For this purpose, the first coolant supply unit 26 is positioned at an angle of approximately 15° to the first surface 14 of the scanner mirror 12, that is, the longitudinal axis of the first coolant supply unit 26 is at an angle of approximately 15° to the first surface 14 of the scanner mirror 12. The outlet of the first coolant supply unit 26, although not shown in detail in Figure 1, 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 thermal energy introduced to the first surface 14 of the scanner mirror 12 by the laser beam 116 at the point of introduction.

[0063] The first coolant supply unit 26 is positioned on the side of the scanner mirror 12 that does not face the drive unit 20, that is, "behind" the scanner mirror 12 as seen from the drive unit 20 along the pivot axis S. This prevents the laser beam 116 directed towards the first surface 14 of the scanner mirror 12 from being obstructed by the first coolant supply unit 26.

[0064] Furthermore, the first coolant supply 26 is configured to direct the first coolant flow 28 symmetrically with respect to the pivot axis S of the scanner mirror 12, above and / or on the surface of the first surface 14, such that the first coolant flow 28 does not substantially act a rotational force on the scanner mirror 12. To this end, the outlet of the first coolant supply 26 is positioned and adjusted so that the first coolant flow 28 strikes the first surface 14 of the scanner mirror 12 symmetrically with respect to the pivot axis S of the scanner mirror 12. This prevents the first coolant flow 28 striking the first surface 14 of the scanner mirror 12 from causing unintended deflection of the scanner mirror 12 with respect to the pivot axis S.

[0065] Furthermore, the scanner mirror cooling device 22 includes a second coolant supply 30 configured to direct a second coolant flow 32 upward and / or onto the second surface 16 of the scanner mirror 12 opposite to the first surface 14. In the first embodiment of the scanner system 10 shown in Figure 2, the second coolant supply 30 is configured to direct the second coolant flow 32 upward and / or onto the second surface 16 of the scanner mirror 12 at an angle of approximately 55° to approximately 90° with respect to the second surface 16.

[0066] To this end, the second coolant supply unit 30 is designed, for example, in a nozzle shape and includes a first coolant supply unit 34 facing the second surface 14 of the scanner mirror 12. The first coolant supply unit 34 is positioned at an angle of approximately 90° with respect to the second surface 16 of the scanner mirror 12; that is, the longitudinal axis of the first coolant supply unit 34 of the second coolant supply unit 30 is positioned at an angle of approximately 90° with respect to the second surface 16 of the scanner mirror 12. The first opening of the first coolant supply unit 34, which is not shown in detail in Figure 1, allows coolant to flow onto the second surface 16 of the scanner mirror 12 at an angle of approximately 55° to approximately 90°. By cooling both the first surface 14 and the second surface 16, the scanner mirror 12 is cooled uniformly, and transient temperature fluctuations of the scanner mirror 12 and temperature gradients within the scanner mirror 12 can be suppressed or at least reduced.

[0067] Similar to the first coolant supply 26, the second coolant supply 30, i.e., the first coolant supply unit 34 in the scanner system 10 shown in Figure 1, is also configured such that the second coolant flow 32 is directed symmetrically with respect to the pivot axis S of the scanner mirror 12, above and / or on the second surface 16, so as not to generate substantially rotational force on the scanner mirror 12. To this end, the outlet of the first coolant supply unit 34 of the second coolant supply 30 is positioned and adjusted so that the second coolant flow 32 strikes the second surface 16 of the scanner mirror 12 symmetrically with respect to the pivot axis S of the scanner mirror 12. This prevents the second coolant flow 32 striking the second surface 16 of the scanner mirror 12 from causing unintended deflection of the scanner mirror 12 with respect to the pivot axis S.

[0068] The first coolant flow 28 and / or the second coolant flow 32 contain a gas, such as clean air or an inert gas. Helium is particularly suitable as an inert coolant because it has high thermal conductivity and allows for effective dissipation.

[0069] The cooling system 24 ultimately serves to cool the internal space of the housing 36 that houses the scanner system 10. In addition to the scanner mirror cooling device 22, which provides localized cooling targeted to the scanner mirror 12, the scanner system 10 is equipped with a "higher" cooling system 24 that cools all elements thus located within the housing 36. The housing 36 may be a scanner housing that houses only the elements of the scanner system 10. However, instead, the housing 36 may house more or all of the elements of the illumination device 112.

[0070] The cooling system 24 supplies a gaseous coolant from a coolant source 38 to the internal space of the housing 36. The gaseous coolant is an inert gas, such as helium. The coolant inlet 40 of the housing 36 is connected to the coolant outlet 44 via a recirculation line 42, allowing the coolant to circulate through the housing 36. A coolant supply line 45 connects the coolant source 38 to the recirculation line 42. This reduces the amount of contamination introduced into the housing 36 compared to a continuous flow of coolant. A heat exchanger 46 is located in the recirculation line, which cools the coolant flowing through the recirculation line 42 before returning it to the housing 36. Additionally, a filter, not shown in Figure 1, may be located in the recirculation line 42 to remove contamination from the coolant before it is returned to the housing 36. As best seen in Figure 1, the recirculation line 42 supplies coolant not only to the cooling system 24 but also to the scanner mirror cooling device 22.

[0071] The check valve 47 is located in the recirculation line 42 in the region of the coolant outlet 44, that is, downstream of the coolant outlet 44. The check valve 47 is configured to release gas from the housing 36 to the environment when the pressure inside the housing 36 exceeds the activation pressure of the check valve 47. Furthermore, the check valve 47 is configured to prevent gas from flowing into the housing 36 even when a negative pressure lower than the ambient pressure spreads inside the housing 36. The check valve 47 reduces or prevents pressure fluctuations inside the housing 36.

[0072] The cooling fin structure provided on the second surface 16 of the scanner mirror 12 acts as a flow controller. In particular, each cooling fin 17 acts as a flow guide element, directing the coolant flow 32 flowing into the second surface 16 of the scanner mirror 12 in a desired direction after it has flowed over the second surface 16 of the scanner mirror 12. For example, the cooling fins 17 may direct the coolant flow 32 so that after it has flowed over the second surface 16 of the scanner mirror 12, it passes over other (optical) elements located inside the housing 32. In addition to the cooling fins 17, further flow controllers and / or flow guide elements (not shown) may be provided to ensure that the coolant flows 28, 32 and the coolant flow guided into and through the housing 36 by the cooling system 24 are directed in a desired direction.

[0073] The second embodiment of the scanner system 10 shown in Figure 3 differs from the arrangement according to Figure 2 in that the first coolant supply 26 is positioned on the side of the scanner mirror 12 facing the drive unit 20, rather than on the side of the scanner mirror 12 not facing the drive unit 20, when viewed from the drive unit 20 along the pivot axis S. In other words, in the arrangement according to Figure 3, the first coolant supply 26 is positioned near the drive unit 20 "in front" of the scanner mirror, rather than "behind" it, when viewed from the drive unit 20 along the pivot axis S. This also prevents the laser beam 116 that strikes the first surface 14 of the scanner mirror 12 from being obstructed by the first coolant supply 26. Otherwise, the structure and operating mode of the scanner system 10 shown in Figure 3 correspond to the structure and operating mode of the arrangement according to Figure 2.

[0074] In the third embodiment of the scanner system 10 shown in Figure 4, the first coolant dispenser 26 is positioned at an angle of approximately 0° to the first surface 14 of the scanner mirror 12, i.e., coaxial with the longitudinal axis of the drive shaft 18. The outlet of the first coolant dispenser 26, although not shown in detail in Figure 4, faces the scanner mirror 12, and the first coolant dispenser 26 provides a first coolant flow 28 that flows over the first surface 14 of the scanner mirror 12 at an angle of approximately 0°, i.e., parallel to the first surface 14 and substantially parallel to the drive shaft 18.

[0075] Furthermore, in the scanner system 10 shown in Figure 4, the first coolant supply unit 26 and the second coolant supply unit 30 are formed by integrating with each other at least partially. In particular, the second coolant supply unit 48 of the second coolant supply unit 30 is formed integrally with the first coolant supply unit 26, and the first coolant supply unit 26 and the second coolant supply unit 48 of the second coolant supply unit 30 form a kind of "shower head nozzle".

[0076] The second coolant supply section 48 of the second coolant supply unit 30 is positioned at an angle of approximately 0° to the second surface 16 of the scanner mirror 12, that is, coaxial with the longitudinal axis of the drive shaft 18, and the outlet of the second coolant supply section 48 faces the scanner mirror 12, although it is not shown in detail in Figure 4. As a result, the second coolant supply section 48 of the second coolant supply unit 30 provides the second coolant flow 32 that flows over the second surface 16 of the scanner mirror 12 at an angle of approximately 0°, that is, parallel to the second surface 16 and substantially parallel to the drive shaft 18.

[0077] Viewed from the drive unit 20 along the pivot axis S, the first coolant supply unit 26 and the second coolant supply unit 48 of the second coolant supply unit 30 are positioned on the side of the scanner mirror 12 that does not face the drive unit 20, that is, the first coolant supply unit 26 and the second coolant supply unit 48 of the second coolant supply unit 30 are positioned "behind" the scanner mirror 12 when viewed from the drive unit 20 along the pivot axis S. This prevents the laser beam 116 that strikes the first surface 14 of the scanner mirror 12 from being obstructed. Otherwise, the structure and operating mode of the scanner system 10 shown in Figure 4 corresponds to the structure and operating mode of the arrangement according to Figure 2-3.

[0078] In the scanner system 10 shown in Figure 4, the first coolant supply unit 34 of the second coolant supply unit 30 shown in Figure 1-2 is omitted. However, it is conceivable to add the first coolant supply unit 34 of the second coolant supply unit 30 or an additional first coolant supply unit 26 to the scanner system 10 according to Figure 4.

[0079] The fourth embodiment of the scanner system 10 shown in Figure 5 differs from the arrangement according to Figure 4 in that the first coolant supply 26 and the second coolant supply section 48 of the second coolant supply 30, which is integrated into the first coolant supply 26, are positioned on the side of the scanner mirror 12 that faces the drive unit 20, rather than on the side of the scanner mirror 12 that does not face the drive unit 20, when viewed from the drive unit 20 along the pivot axis S. However, the first coolant supply 26 and the second coolant supply section 48 of the second coolant supply 30, which is integrated into the first coolant supply 26, are positioned at an angle of approximately 0° 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.

[0080] Furthermore, the first coolant supply unit 34 of the second coolant supply unit 30 is located as already described in relation to Figure 2-3 and is positioned at an angle of approximately 90° to the second surface 16 of the scanner mirror 12, directing the first portion 32a of the second coolant flow 32 above and / or onto the second surface 16 of the scanner mirror 12 at an angle of approximately 55° to approximately 90° with the second surface 16.

[0081] The outlet 50 of the first coolant supply unit 26 is directed toward the first surface 14 of the scanner mirror 12, directing the first coolant flow 28 above and / or onto the first surface 14 of the scanner mirror 12 at an angle of approximately 0° to approximately 10° with respect to the first surface 14. Similarly, the outlet 52 of the second coolant supply unit 48 of the second coolant supply unit 30 is directed toward the second surface 16 of the scanner mirror 12, directing the second portion 32b of the second coolant flow 32 above and / or onto the second surface 16 of the scanner mirror 12 at an angle of approximately 0° to approximately 10° with respect to the second surface 16. Otherwise, the structure and operating modes of the scanner system 10 shown in Figure 5 correspond to the structure and operating modes of the array according to Figure 2-4.

[0082] The fifth embodiment of the scanner system 10 shown in Figure 6 differs from the arrangement according to Figure 5 in that the first coolant supply 26 and the second coolant supply section 48 of the second coolant supply 30, which is formed by integrating with the first coolant supply 26, are integrated with the drive shaft 18. Otherwise, the structure and operating mode of the scanner system 10 shown in Figure 6 correspond to the structure and operating mode of the arrangement according to Figure 5.

Claims

1. A scanner system (10) used in an apparatus (100) for manufacturing a three-dimensional workpiece by irradiating a raw material powder layer with electromagnetic radiation or particle beams, wherein the scanner system (10) is A rotatable scanner mirror (12) having a first surface (14) configured to be illuminated by an irradiation beam (116) emitted from an irradiation source (114), A scanner mirror cooling device (22) having a first coolant supply (26) configured to direct a first coolant flow (28) upward and / or onto the first surface (14) of the scanner mirror (12), A scanner system (10) is provided with the following:

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

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

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

5. The scanner system (10) according to claim 3 or 4, wherein the second coolant supply (30) comprises a first coolant supply unit (34) facing the second surface (16) of the scanner mirror (12) and positioned at an angle of about 70° to about 110°, preferably about 80° to 100°, and particularly preferably about 90° with respect 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 (30) comprises a second coolant supply unit (48) positioned at an angle of about 0° to about 30°, preferably about 0° to about 25°, and particularly preferably about 0° to about 20° with respect to the second surface (16) of the scanner mirror (12).

7. The scanner system (10) according to any one of claims 3 to 6, wherein the first coolant supply (26) and the second coolant supply (30) are formed integrally with each other in at least part of a portion.

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

9. The scanner mirror (12) is connected to a drive unit (20) via a drive shaft (18) that extends along the pivot axis (S) of the scanner mirror (12). The first coolant supply (26) is positioned on the side of the scanner mirror (12) that does not face the drive unit (20), or on the side that faces the drive unit (20), and / or The first coolant supply (26) is arranged coaxially or parallel to the longitudinal axis of the drive shaft (18) and / or integrated with the drive shaft (18). A scanner system (10) according to any one of claims 1 to 8.

10. The first coolant supply (26) is configured such that the first coolant flow (28) is directed symmetrically with respect to the pivot axis (S) of the scanner mirror (12) above and / or onto the first surface (14) such that substantially no rotational force is applied by the first coolant flow (28), and / or The second coolant supply (30) is configured such that the second coolant flow (32) is directed symmetrically with respect to the pivot axis (S) of the scanner mirror (12) above and / or on the second surface (16) such that substantially no rotational force is applied by the second coolant flow (32). A scanner system (10) according to any one of claims 1 to 9.

11. The scanner system (10) according to any one of claims 1 to 10, wherein the first coolant flow (28) and / or the second coolant flow (32) comprises clean air or an inert gas such as helium, argon, nitrogen, or a mixture of gases.

12. The enclosure (36) housing the scanner system (10) is further provided with a cooling system (24) for cooling the internal space of the enclosure (36), The cooling system (24) in particular includes a recirculation line (42) connected to the coolant inlet (40) and coolant outlet (44) of the housing (36), A scanner system (10) according to any one of claims 1 to 11.

13. A method for operating a scanner system (10) used in an apparatus (100) for manufacturing a three-dimensional workpiece by irradiating a raw material powder layer with electromagnetic radiation or particle beams, The irradiation beam (116) emitted from the irradiation source (114) irradiates the first surface (14) of at least one rotatable scanner mirror (12), The first coolant supply (26) of the scanner mirror cooling device (22) directs the first coolant flow (28) upward and / or onto the first surface (14) of the scanner mirror (12), Methods that include...

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

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

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

17. The first coolant supply (26) directs the first coolant flow (28) symmetrically with respect to the pivot axis (S) of the scanner mirror (12) above and / or on the surface of the first surface (14) such that substantially no rotational force is applied by the first coolant flow (28), and / or The second coolant supply (30) directs the second coolant flow (32) symmetrically with respect to the pivot axis (S) of the scanner mirror (12) above and / or on the second surface (16) such that substantially no rotational force is applied by the second coolant flow (32). The method according to any one of claims 13-16.

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

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