Transmission element system and apparatus for producing a three-dimensional work piece

Abstract

A transmission element system (10) for use in an apparatus (100) for producing a three-dimensional work piece is provided. The transmission element system (10) comprises a housing (12) which is configured to be arranged so as to cover a radiation beam opening (106) provided in a process chamber (102) of the apparatus (100) for producing a three-dimensional work piece. Further, the transmission element system (10) comprises a transmission element carrier (14) which comprises at least one transmission element (16) configured to allow the transmission of a radiation beam emitted by an irradiation device (104) of the apparatus (100) for producing a three-dimensional work piece. The transmission element carrier (14) is movable relative to the housing (12) between a first position, wherein the transmission element carrier (14) is accommodated in the housing (12) such that a radiation beam emitted by the irradiation device (104) passes through the at least one transmission element (16) of the transmission element carrier (14) into the process chamber (12), and a second position, wherein the transmission element carrier (14) is arranged outside of the housing (12). A connecting system (18) is attached to the housing (12), wherein the transmission element carrier (14) is configured to be releasably attached to the connecting system (18) in order connect the transmission element carrier (14) to the housing (12).

Description

[0001] Transmission element system and apparatus for producing a three-dimensional work piece

[0002] The present invention relates to a transmission element system for use in an apparatus for producing a three-dimensional work piece by irradiating layers of a raw material powder with electromagnetic or particle radiation. Further, the invention relates to an apparatus for producing a three-dimensional work piece by irradiating layers of a raw material powder with electromagnetic or particle radiation which is equipped with a transmission element system of this kind.

[0003] Powder bed fusion is an additive layering process by which pulverulent, in particular metallic and / or ceramic raw materials can be processed to three-dimensional work pieces of complex shapes. To that end, a raw material powder layer is applied onto a carrier and subjected to electromagnetic or particle radiation in dependence on the desired geometry of the work piece that is to be produced. The electromagnetic or particle radiation penetrating into the powder layer causes heating and consequently melting or sintering of the raw material particles. Further raw material powder layers are then applied successively to the layer on the carrier that has already been subjected to radiation treatment, until the work piece has the desired shape and size. Powder bed fusion methods can be used in particular for the production of prototypes, tools, replacement parts or medical prostheses on the basis of CAD data.

[0004] Welding smoke generated in a powder bed fusion process upon irradiating and hence melting a raw material powder may contaminate the interior of a process chamber and in particular a transmission element, e.g. in the form of a lens or window, through which a radiation beam is directed into the process chamber. Typically, such a transmission element is arranged in the region of a top wall of the process chamber. Due to the deposition of welding smoke condensate on the transmission element, a gradually increasing part of the radiation energy emitted by the irradiation system may be absorbed by the deposited material.

[0005] EP 3 321 003 Bl describes an apparatus for producing a three-dimensional workpiece by a powder bed fusion process, wherein the absorption of radiation energy emitted by the irradiation system by welding smoke condensate material deposited onto the surface of the transmission element can be reduced by establishing suitable protective gas flows within the process chamber. However, it may still be required to clean or to exchange the transmission element, e.g. after completion of a build process before a new build process is started.

[0006] The present invention is directed at the object of providing a transmission element system and an apparatus for producing a three-dimensional work piece by irradiating layers of a raw material powder with electromagnetic or particle radiation which allow an easy and efficient cleaning and / or exchange of a transmission element through which a radiation beam to be irradiated onto the raw material powder layers is directed into the process chamber.

[0007] This object is addressed by a transmission element system as defined in claim 1 and an apparatus for producing a three-dimensional work piece as defined in claim 14.

[0008] A transmission element system for use in an apparatus for producing a three- dimensional work piece comprises a housing which is configured to be arranged so as to cover a radiation beam opening provided in a process chamber of the apparatus for producing a three-dimensional work piece. The process chamber may be sealed against the environment. Further, the process chamber may be provided with a gas inlet and a gas outlet such that a gas, in particular an inert gas such as, for example, Argon or Nitrogen may be directed through the process chamber. The inert gas directed through the process chamber may establish an inert gas atmosphere within the process chamber. Further, an inert gas stream exiting the process chamber through the gas outlet may serve to remove particulate impurities from the process chamber.

[0009] The radiation beam opening may be provided in a wall of the process chamber which may face an irradiation device of the apparatus for producing a three-dimensional workpiece. In particular, the radiation beam opening may be provided in a top wall of the process chamber. The radiation beam opening provided in the process chamber serves to allow a radiation beam emitted by the irradiation device to enter an interior of the process chamber.

[0010] The housing of the transmission element system may be formed separate from the process chamber and / or the irradiation of the apparatus for producing a three- dimensional workpiece. In such a case, the housing may be fixedly or releasably connectable to the process chamber and / or the irradiation device, in particular a (top) wall of the process chamber which faces the irradiation device and / or a (bottom) wall ask the irradiation device which faces the process chamber. Alternatively, the housing may be fixedly or releasably connectable to a support structure which is designed, for example, as described in EP 3 713 694 Al and which is configured to independently support the process chamber, the irradiation unit and the housing of the transmission element system.

[0011] It is, however, also conceivable that the housing of the transmission element system is formed integral with a process chamber, in particular a (top) wall of the process chamber which faces the irradiation device. As a further alternative, it is conceivable that the housing of the transmission element system is formed integral with an irradiation device of the apparatus for producing a three-dimensional workpiece. For example, the housing of the transmission element system may be formed integral with a (bottom) wall of an irradiation device housing which faces the process chamber. Finally, the housing of the transmission element system may also be formed integral with a support structure as described, for example, in EP 3 713 694 Al.

[0012] The transmission element system further is provided with a transmission element carrier which comprises at least one transmission element configured to allow the transmission of a radiation beam emitted by an irradiation device of the apparatus for producing a three-dimensional work piece. The transmission element carrier may comprise a plurality of transmission elements which may be formed separate from each other. In such a case, preferably each of the plurality of transmission elements allows the transmission of a radiation beam emitted by the irradiation device of the apparatus for producing a three-dimensional workpiece. It is, however, also conceivable that more than one radiation beam emitted by the irradiation device is directed through and hence transmitted by a single transmission element.

[0013] The transmission element may be configured to allow the transmission of a beam of electromagnetic or particle radiation. The transmission element may, for example, be designed in the form of a window. Alternatively, the transmission element may comprise or consist of an optical element, in particular a lens. The material of the transmission element may be selected in dependence on the type of the radiation emitted by the irradiation device in order to ensure the desired transmissibility of the transmission element for the radiation beam emitted by the irradiation device. Further, the material of the transmission element should be selected in such a manner that the transmission element is capable of withstanding the thermal loads acting on the transmission element during operation of the apparatus for producing a three-dimensional work piece. For example, the transmission element may be made of a glass material or a suitable polymer material. If desired, the transmission element, in the region of a surface facing the interior of the process chamber, may be provided with a surface layer which minimizes the adhesion and deposition of welding smoke condensate onto the surface of the transmission element.

[0014] At least one surface of the transmission element carrier and / or at least one surface of the housing may be configured to reflect laser radiation and / or thermal radiation. The laser radiation and / or thermal radiation may be emitted from the process chamber during operation of the apparatus for producing a three-dimensional work piece. The at least one reflective surface of the transmission element carrier may be a surface which faces the process chamber when the transmission element carrier is arranged in its first position. Similarly, the at least one surface of the housing may be a surface which faces the process chamber. It is, however, also conceivable that more than one surface or all surfaces of the transmission element carrier and / or of the housing is / are configured to reflect laser radiation and / or thermal radiation. The at least one reflective surface may be produced by a suitable surface treatment of surface coating. By providing the transmission element carrier and / or the housing with at least one reflective surface, the absorption of laser radiation and / or thermal radiation and thus heating of the transmission element carrier, the housing and further components arranged in thermal contact with the transmission element carrier and / or the housing can be reduced.

[0015] The transmission element carrier may be movable relative to the housing between a first position and a second position. In its first position, the transmission element carrier is accommodated in the housing such that a radiation beam emitted by the irradiation device passes through the at least one transmission element of the transmission element carrier into the process chamber, i.e. into an interior of the process chamber. Thus, when the transmission element carrier is arranged in its first position, the transmission element is aligned with the radiation beam opening provided in the process chamber such that the radiation beam can be transmitted through the transmission element and enter the process chamber through the radiation beam opening. In its second position, the transmission element carrier is arranged outside of the housing. When the transmission element carrier is arranged outside of the housing, the transmission element is no longer aligned with radiation beam opening provided in the process chamber.

[0016] The transmission element system further comprises a connecting system attached to the housing. The connecting system may be fixedly attached to the housing. It is, however, also conceivable that the connecting system is releasably attached to the housing such that the connecting system can be detached from the housing, for example for maintenance purposes. The transmission element carrier is configured to be releasably attached to the connecting system in order to connect the transmission element carrier to the housing. Thus, the connecting system provides a releasable connection of the transmission element carrier to the housing which allows, on the one hand, a secure fixation of the transmission element carrier to the housing, but, on the other hand, allows the transmission element carrier to be released from the housing, for example for cleaning or for being exchanged.

[0017] The transmission element system according to the present invention allows a particularly easy and efficient cleaning and / or exchange of a transmission element through which a radiation beam is directed into the process chamber. Consequently, manufacturing processes in an apparatus for producing a three-dimensional workpiece which is equipped with the transmission element system can be optimized and downtimes of the apparatus can be minimized.

[0018] In a preferred embodiment of the transmission element system, the connecting system is movable relative to the housing so as to allow a sliding movement of the transmission element carrier relative to the housing between the first and the second position. A connecting system which is movable relative to the housing allows a displacement of the transmission element carrier relative to the housing between the first and the second position while still being connected to the housing. Thus, a controlled movement of the transmission element carrier relative to the housing between the first and the second position is made possible and damages to the transmission element carrier and the transmission element provided therein can be prevented. The sliding movement between the first and the second position may take place along a longitudinal axis of the housing and / or parallel to a transmission plane defined by the at least one transmission element.

[0019] The connecting system may comprise a first supporting surface configured to support a first end region of the transmission element carrier. Further, the connecting system may comprise a second supporting surface which is spaced from the first supporting surface along the longitudinal axis of the housing and configured to support a second end region of the transmission element carrier which is arranged opposed of the first and region. The first and the second supporting surface may be configured to support the transmission element carrier in its first position and in its second position such that the transmission element carrier cannot fall down while being removed from the housing and when being arranged in its second position outside of the housing.

[0020] Further, the connecting system may comprise at least one guide rail for guiding the movement of the transmission element carrier relative to the housing between its first and second position. The at least one guide rail may extend between the first supporting surface and the second supporting surface. Alternatively or additionally, the at least one guide rail may extend substantially parallel to the longitudinal axis of the housing. Further, the at least one guide rail may extend adjacent to a sidewall of the housing, the sidewall of the housing extending substantially parallel to the longitudinal axis of the housing. Preferably, the connecting system comprises two guide rails which extend substantially parallel to and at a distance from each other between the first supporting surface and the second supporting surface and certainly parallel to the longitudinal axis of the housing. One guide rail may extend adjacent to each housing sidewall which in turn extends substantially parallel to the longitudinal axis of the housing.

[0021] The transmission element system may comprise at least one latching element which is configured to releasably latch the transmission element carrier in its first position. By disengaging the latching element, the transmission element carrier is released so as that it can be moved from its first position into its second position.

[0022] The transmission element system may further comprise a cooling device which is configured to cool the housing and / or the transmission element carrier when the transmission element carrier is accommodated in the housing in its first position. The presence of a cooling device mitigates the effect of temperature changes acting on the housing and / or the transmission element carrier which might cause displacements of the housing and / or the transmission element carrier due to thermal expansion. The cooling device may comprise a cooling circuit provided in the housing, in the connecting system and / or in the transmission element carrier. The cooling circuit may be flown through with a suitable gaseous or liquid coolant, for example air or water.

[0023] It is, however, also conceivable to use at least a part of the housing and / or the connecting system which is in direct thermal contact with the transmission element carrier and which is capable of directing heat away from the transmission element carrier as a cooling element of the cooling device. For example, the at least one guide rail of the connecting system may act as a cooling element which directs heat away from the transmission element carrier. Preferably, the cooling element is made of a material having a high thermal conductivity. In particular, the cooling element may be made of metal, such as aluminum. Further, it is conceivable that the housing and / or the transmission element carrier may comprise or may be made of a material having a high thermal conductivity. In particular, the housing and / or the transmission element carrier may comprise or may be made of metal such as aluminum.

[0024] Further, the transmission element system may comprise a thermal expansion compensation arrangement which is configured to compensate a thermal expansion of the housing and / or the transmission element carrier when the transmission element carrier is accommodated in the housing in its first position. In other words, the thermal expansion compensation arrangement serves to maintain a correct positioning of the transmission element carrier relative to the housing even in case the transmission element carrier and / or the housing is subject to a deformation due to thermal expansion.

[0025] The thermal expansion compensation arrangement may comprise a first abutting device provided on the housing and / or on the connecting system which is configured to interact with a second abutting device provided on the transmission element carrier when the transmission element carrier is accommodated in the housing in its first position. Abutting surfaces of the first and the second abutting devices may extend substantially perpendicular to the longitudinal axis of the housing and substantially perpendicular to the transmission plane. When the transmission element carrier is arranged in its first position, the first and the second abutting devices thus define a correct positioning of the transmission element carrier relative to the housing in a direction along the longitudinal axis of the housing.

[0026] The thermal expansion compensation arrangement may further comprise a biasing element which biases the second abutting device against the first abutting device when the transmission element carrier is accommodated in the housing in its first position. The biasing device thus serves to maintain the first and the second abutting devices in contact with each other even in case of a thermal deformation of the housing and / or the transmission element carrier. For example, the biasing device may be designed in the form of spring or a spring package.

[0027] The housing of the transmission element system may comprise a bottom element which is configured to face an interior of the process chamber when the transmission element system is mounted in an apparatus for producing a three-dimensional work piece. Further, the housing may comprise a cover element which is configured to face away from the interior of the process chamber when the transmission element system is mounted in an apparatus for producing a three-dimensional work piece. The bottom element and / or the cover element may be dimensioned and shaped so as to at least cover the radiation beam opening provided in the process chamber. When being arranged in its first position, the transmission element carrier preferably is sandwiched between the bottom element and the cover element of the housing.

[0028] The bottom element may be provided with at least one opening which is aligned with the at least one transmission element when the transmission element carrier is accommodated in the housing in its first position. Further, the cover element may be provided with at least one opening which is aligned with the at least one transmission element when the transmission element carrier is accommodated in the housing in its first position. Such a design of the housing allows a radiation beam emitted by the irradiation device to pass through the opening provided in the cover element, the transmission element and finally the opening provided in the bottom element before entering the interior of the process chamber. In case the transmission element carrier comprises more than one transmission element, the bottom element and / or the cover element may be provided with a corresponding plurality of openings being aligned with each of the transmission elements. It is, however, also conceivable that the bottom element and / or the cover element are provided with a single opening or a plurality of openings which is / are aligned with a plurality of transmission elements so as to allow a radiation beam emitted by the irradiation device to pass through the opening(s) provided in the cover element, the transmission element and finally the opening(s) provided in the bottom element before entering the interior of the process chamber.

[0029] The transmission element system may further comprise a first sealing element which is attached to the transmission element carrier so as to surround the at least one transmission element and which is configured to seal the transmission element carrier against the housing. For example, the first sealing element may be accommodated in a groove formed in the transmission element carrier. Preferably, the first sealing element is attached to a surface of the transmission element carrier which faces away from the process chamber. The first sealing element then is configured to seal the transmission element carrier against the cover element of the housing. In particular in case the transmission element carrier is movable relative to the housing between its first and its second position by a sliding movement, a pressure acting on the first sealing element is evenly distributed over the first sealing element which results in a reliable sealing effect and hence prevents leakages and excess wear of the first sealing element.

[0030] Further, at least one second sealing element may be provided which is configured seal the housing, in particular the cover element the housing, against the irradiation device when the transmission element system is mounted in an apparatus for producing a three-dimensional work piece. Preferably, the second sealing element attached to the housing. It is, however, also conceivable that the second sealing element is attached to the irradiation device. Preferably, the second sealing element surrounds the at least one opening provided in the cover element. For example, the second sealing element may be accommodated in a groove formed in the housing, in particular the cover element of the housing, or a groove formed in the irradiation device. In case the cover element of the housing comprises more than one opening so as to allow plural radiation beams emitted by the irradiation device to pass through a plurality of transmission elements, a second sealing element may be associated with each opening. In other words, a plurality of second sealing elements may be provided, wherein each second sealing element surrounds one opening provided in the cover element.

[0031] Further, the transmission element system may comprise at least one third sealing element. Preferably, the third sealing element is configured to seal the housing, in particular the bottom element of the housing, against the process chamber when the transmission element system is mounted in an apparatus for producing a three- dimensional work piece. For example, the third sealing element may be attached to the housing. The third sealing element may, however, also be attached to the process chamber, in particular a region of a (top) wall of the process chamber which faces the housing of the transmission element system. Preferably, the third sealing element surrounds the at least one opening provided in the bottom element of the housing. The third sealing element may be accommodated in a groove formed in the housing, in particular the bottom element of the housing, or a (top) wall of the process chamber. In case the bottom element of the housing comprises more than one opening so as to allow plural radiation beams emitted by the irradiation device to pass into the process chamber, a third sealing element may be associated with each opening. In other words, a plurality of third sealing elements may be provided, wherein each third sealing element surrounds one opening provided in the cover element. In a preferred embodiment of the transmission element system, the first sealing element is arranged in a plane substantially parallel to the transmission plane defined by the at least one transmission element. It is, however, also conceivable that the first sealing element comprises a first portion and a second portion. The first portion and the second portion may be formed integral with each other. The first portion may be arranged in a plane substantially parallel to the transmission plane defined by the at least one transmission element. The second portion may be arranged in a plane substantially perpendicular to the transmission plane defined by the at least one transmission element. Preferably, the second portion of the first sealing element is arranged in the second end region of the transmission element carrier which faces away from the housing when the transmission element carrier is arranged in its second position outside of the housing.

[0032] The transmission element carrier may comprise a flange element configured to abut against an end face of the housing when the transmission element carrier is accommodated in the housing in its first position. Preferably, the flange element is sealed against the end face of the housing by means of a fourth sealing element. The fourth sealing element may be attached to the flange element. Alternatively or additionally, the fourth sealing element may extend in a plane substantially perpendicular to the transmission plane defined by the at least one transmission element.

[0033] The thickness of transmission element carrier in a direction perpendicular to the transmission plane defined by the at least one transmission element may decrease in a direction of movement of the transmission element carrier when the transmission element carrier is moved from its second position into its first position. Alternatively or additionally, the thickness of the bottom element and / or the cover element of the housing in a direction perpendicular to the transmission plane defined by the at least one transmission element may increase in a direction of movement of the transmission element carrier when the transmission element carrier is moved from its second position into its first position.

[0034] Thus, the transmission element carrier may have a wedge-shaped design, wherein a bottom surface of the transmission element carrier and / or a top surface of the transmission element carrier may be inclined relative to the transmission plane in order to provide for the decreasing thickness of the transmission element carrier in a direction of movement of the transmission element carrier when the transmission element carrier is moved from its second position into its first position. A wedge- shaped design of the transmission element carrier promotes the slipping off of particulate impurities from the transmission element carrier, in particular in an area adjacent to the first sealing element. Consequently, the first sealing element is protected from being polluted by particulate impurities. As a result, an optimum sealing effect of the first sealing element can be maintained and excess wear of the first sealing element can be prevented.

[0035] Similarly, the housing, i.e. the bottom element and / or the cover element of the housing may be provided with a complementary wedge-shaped design, i.e. a top surface of the bottom element facing the transmission element carrier and / or a bottom surface of the cover element facing the transmission element carrier may be inclined relative to the transmission plane in order to provide for the increasing thickness of the bottom element and / or the cover element in a direction of movement of the transmission element carrier when the transmission element carrier is moved from its second position into its first position.

[0036] In a preferred embodiment, a bottom surface of the transmission element carrier extends substantially parallel to the transmission plane, while a top surface of the transmission element carrier is inclined relative to the transmission plane in order to provide for the decreasing thickness of the transmission element carrier in the direction of movement of the transmission element carrier when the transmission element carrier is moved from its second position into its first position. For example, the top surface of the transmission element carrier may extend at an angle of 1 to 5° relative to transmission plane. Such a transmission element carrier design is particularly suitable for cooperating with a housing, wherein a bottom surface of the cover element is inclined relative to the transmission plane in order to provide for the increasing thickness of the cover element in a direction of movement of the transmission element carrier when the transmission element carrier is moved from its second position into its first position. For example, the inclined bottom surface of the cover element may extend substantially parallel to the inclined top surface of the transmission element carrier and / or at an angle of 1 to 5° relative to transmission plane.

[0037] Alternatively, a top surface of the transmission element carrier may extend substantially parallel to the transmission plane, while a bottom surface of the transmission element carrier is inclined relative to the transmission plane in order to provide for the decreasing thickness of the transmission element carrier in the direction of movement of the transmission element carrier when the transmission element carrier is moved from its second position into its first position. For example, the bottom surface of the transmission element carrier may extend at an angle of 1 to 5° relative to transmission plane. Such a transmission element carrier design is particularly suitable for cooperating with a housing, wherein a top surface of the bottom element is inclined relative to the transmission plane in order to provide for the increasing thickness of the bottom element in a direction of movement of the transmission element carrier when the transmission element carrier is moved from its second position into its first position. For example, the inclined top surface of the bottom element may extend substantially parallel to the inclined bottom surface of the transmission element carrier and / or at an angle of 1 to 5° relative to transmission plane.

[0038] The transmission element carrier, when viewed in top view, may have a trapezoidal shape. It is, however, also conceivable that the transmission element carrier, when viewed in top view, has a rectangular shape. The shape of the housing, i.e. the shape of the bottom element and the cover element of the housing, preferably is adapted to the shape of the transmission element carrier. Thus, in particular in case the transmission element carrier, when viewed in top view, has a trapezoidal shape, the bottom element and / or the cover element of the housing, when viewed in top view, may also have a trapezoidal shape. If, however, the transmission element carrier, when viewed in top view, has a rectangular shape, the bottom element and / or the cover element of the housing, when viewed in top view, preferably also have a rectangular shape.

[0039] The transmission element system may further comprise a first shutter which is configured to be moved between an active position and a stored position. In its active position, the first shutter preferably covers the at least one transmission element. When the first shutter is arranged in its stored position, the at least one transmission element may be exposed. Thus, when being arranged in its active position, the first shutter covers and hence protects the at least one transmission element. The first shutter may, for example, be made from a metal foil, in particular a stainless steel foil. In case the transmission element carrier is provided with more than one transmission element, the first shutter preferably is dimensioned and arranged so as to cover all the transmission elements provided in the transmission element carrier. Alternatively, it is, however, also conceivable that the transmission element system is provided with a plurality of first shutters that are associated with one or more transmission elements. Preferably, the first shutter comprises an automatic activation mechanism which is configured to deploy the first shutter from its stored position into its active position when the transmission element carrier is moved from its first position into its second position. The automatic activation mechanism ensures that the first shutter is activated so as to protect the transmission element when the transmission element carrier is removed from the housing. Consequently, damages to the transmission element can reliably be prevented.

[0040] The transmission element system may further comprise a second shutter which is configured to be moved between an active position and a stored position. In its active position, the second shutter may extend within the housing in place of the transmission element carrier. In particular, the second shutter, when being arranged in its active position, may cover the at least one opening provided in the bottom element of the housing and / or the at least one opening provided in the cover element of the housing when the transmission element carrier is arranged outside of the housing in its second position. Thus, when being arranged in its active position, the second shutter may separate the process chamber from the irradiation device and hence protect the components, in particular the optical components of the irradiation device from being contaminated by impurities present in the process chamber. The second shutter may, for example, be made from a metal foil, in particular a stainless steel foil.

[0041] Preferably, the second shutter comprises an automatic activation mechanism which is configured to deploy the second shutter from its stored position into its active position when the transmission element carrier is moved from its first position into its second position. The automatic activation mechanism ensures that the second shutter is activated so as to the process chamber from the irradiation device when the transmission element carrier is removed from the housing. Consequently, the contamination of the components of the irradiation device can reliably be prevented.

[0042] An apparatus for producing a three-dimensional work piece comprises a process chamber. Further, the apparatus comprises a carrier configured to receive a raw material powder. The carrier may be accommodated in the process chamber. It is, however, also conceivable that the process chamber is movable across the carrier. The carrier may be a rigidly fixed carrier having a surface onto which the raw material powder is applied in order to be subjected to electromagnetic or particle radiation. Preferably, however, the carrier is designed to be displaceable in vertical direction, so that, with increasing construction height of a work piece, as it is built up in layers from the raw material powder, the carrier can be moved downwards in the vertical direction. The raw material powder applied onto the carrier within the process chamber is preferably a metallic powder, in particular a metal alloy powder, but may also be a ceramic powder or a powder containing different materials. The powder may have any suitable particle size or particle size distribution. It is, however, preferable to process powders of particle sizes < 100 pm.

[0043] The apparatus further comprises an irradiation device configured to selectively irradiate electromagnetic or particle radiation onto the raw material powder on the carrier in order to produce a work piece made of said raw material powder by an additive layer construction method. By means of the irradiation device, the raw material powder applied onto the carrier may be subjected to electromagnetic or particle radiation in a site-selective manner in dependence on the desired geometry of the work piece that is to be produced. The irradiation device may comprise a radiation beam source, in particular a laser beam source, and additionally may comprise an optical unit for guiding and / or processing a radiation beam emitted by the radiation beam source. The optical unit may comprise optical elements such an object lens and a scanner unit, the scanner unit preferably comprising a diffractive optical element and a deflection mirror.

[0044] Further, the apparatus comprises an above described transmission element system. The transmission element system may be arranged between the process chamber and the irradiation device. In particular, the transmission element system may be arranged between a top wall of the process chamber and the irradiation device.

[0045] Preferably, the housing of the transmission element system is arranged between the process chamber and the irradiation device such that the at least one transmission element is aligned with the radiation beam opening provided in the process chamber in order to allow the transmission of the radiation beam emitted by the irradiation device through the transmission element and the radiation beam opening into the process chamber.

[0046] Preferably, the process chamber is thermally and / or mechanically decoupled from the irradiation device. Consequently, thermal and / or mechanical loads acting on the process chamber are prevented from being transferred to the irradiation device. The thermal and / or mechanical decoupling of the irradiation device from the process chamber and vice versa may, for example, be achieved with the aid of a support structure which represents a support frame independently supporting the process chamber and the irradiation unit as described in EP 3 713 694 Al.

[0047] Further, the housing of the transmission element system may be thermally and / or mechanically decoupled from the process chamber and / or the irradiation device. Consequently, thermal and / or mechanical loads acting on the process chamber and / or the irradiation device are prevented from being transferred to the transmission element system. Thus, the influence of thermal and / or mechanical loads acting on the process chamber and / or the irradiation device on the positioning of the transmission element system and in particular the transmission element relative to the process chamber and the irradiation device can be minimized. The thermal and / or mechanical decoupling of the housing of the transmission element system from the irradiation device and / or the process chamber and vice versa may, for example, be achieved with the aid of a support structure which is designed similar to the support structure described in EP 3 713 694 Al and which is configured to independently support the process chamber, the irradiation unit and the housing of the transmission element system.

[0048] The at least one transmission element may be arranged offset relative to the radiation beam opening provided in the process chamber in the direction of the irradiation device such that the at least one transmission element is arranged outside of an interior space of the process chamber. As a result, the transmission element is less prone to being contaminated by particulate impurities present in the process chamber.

[0049] The apparatus may further comprise at least one storage station which is configured to accommodate at least one exchange transmission element carrier. The storage station thus is configured to store at least one ready-to-use exchange transmission element carrier which can be connected to the connecting system of the transmission element system and used at any time on request.

[0050] Further, at least one maintenance station may be provided which is configured to accommodate a used transmission element carrier. The maintenance station may be configured to provide for inspection, cleaning and / or repair of the used transmission element carrier in order to prepare a used transmission element carrier for being reused in the transmission element system. For example, the maintenance station may be equipped with sensors or other test equipment for testing and inspecting the quality and the condition of the transmission element installed in the transmission element carrier. In particular, dimensions, surface quality, electrical properties and other relevant parameters of the transmission element may be tested in the maintenance station. The data detected by test equipment provided in the maintenance station may be evaluated by a suitable control device, wherein the control device may be associated with the maintenance station only or may be integrated into a superordinate control device of the transmission element system or the apparatus for producing a three-dimensional work piece.

[0051] The apparatus may also comprise an enclosure configured to receive the transmission element carrier when the transmission element carrier is moved from its first position within the housing into its second position outside of the housing. The enclosure may be sealed such that the transmission element carrier is protected from dust and / or other environmental impacts. The enclosure may be designed in the form of a separate component which is configured to accommodate the transmission element carrier as soon as the transmission element carrier is moved from its first position within the housing into its second position outside of the housing. It is, however, also conceivable, that the enclosure is a component of the storage station and / or the maintenance station so that the transmission element carrier is accommodated within the enclosure as soon as the transmission element carrier enters the storage station and / or the maintenance station.

[0052] Moreover, the apparatus may comprise a transfer system for automatically transferring the transmission element carrier between different positions. For example, the transfer system may be configured to transfer a used transmission element carrier from its first position within the housing into its second position outside of the housing. The transfer system may also be configured to transfer the transmission element carrier into the maintenance station. The second position outside of the housing may be an "intermediate" position the transmission element carrier assumes after being removed from its first position and before being further transferred to the maintenance station. It is, however, also conceivable that the second position is arranged within the maintenance station such that the transmission element carrier can be transferred from its first position directly into the maintenance station. It is conceivable that the transmission element carrier is housed within the enclosure when the transmission element carrier is moved from the first position to the second position and / or to the "intermediate" position. In all positions the transmission element carrier may be protected from dust and / or other environmental impacts. Alternatively or additionally, the transfer system may be configured to transfer an exchange transmission element carrier from the storage station into its first position within the housing. The transfer of an exchange transmission element carrier between the storage station and the first position within the housing may be effected via an "intermediate" second position outside of the housing. It is, however, also conceivable that the second position is arranged within the storage station such that the exchange transmission element carrier can be transferred from its storage station directly into the first position.

[0053] Further, the transfer system may be configured to transfer a used transmission element carrier, preferably after being processed in the maintenance station, from the maintenance station to the storage station. The transfer system may comprise robot arms, conveyor belts or other automatic mechanisms which provide for an automatic, fast and reliable transfer of the transmission element carriers between the housing of the transmission element system, the storage station and the maintenance station.

[0054] The transfer system may be configured to transfer a used transmission element carrier from the maintenance station to the storage station only in case the transmission element carrier, by the control device of the maintenance station, is considered to be suitable for being reused. To achieve this, the control device may be configured to control not only the operation of the maintenance station, but also the operation of the transfer system. Alternatively, a separate control device may be provided for controlling the operation of the transfer system which communicates with the control device of the maintenance station. In addition to the storage station and the maintenance station, a defective unit storage station may be provided which is configured to accommodate at least one exchange transmission element carrier which, by the control unit of the maintenance station, is considered to be defective and hence no longer usable in the transmission element system. Consequently, the transfer system may also be configured to transfer a used transmission element carrier from the maintenance station to the defective unit storage station.

[0055] A storage station may be arranged relative to the housing such that an exchange transmission element carrier, by means of the transfer system, is transferable from the storage station into its second position outside of the housing by a translatory movement in a first direction parallel to the transmission plane and perpendicular to the direction of movement of the transmission element carrier when the transmission element carrier is moved between its second position and its first position. Further, a maintenance station may be arranged relative to the housing such that a used transmission element carrier, by means of the transfer system, is transferable from its second position outside of the housing into the maintenance station by a translatory movement in the first direction parallel to the transmission plane and perpendicular to the direction of movement of the transmission element carrier when the transmission element carrier is moved between its second position and its first position. In such an arrangement, the storage station and the maintenance station may be arranged in a plane parallel to the transmission plane and adjacent to opposing sides of a transmission element carrier being arranged in its second position outside of the housing.

[0056] Further, a storage station may be arranged relative to the housing such that an exchange transmission element carrier, by means of the transfer system, is transferable from the storage station into its second position outside of the housing by a translatory movement in a second direction perpendicular to the transmission plane and optionally in a third direction parallel to the direction of movement of the transmission element carrier when the transmission element carrier is moved from its second position into its first position. Moreover, a maintenance station may be arranged relative to the housing such that a used transmission element carrier, by means of the transfer system, is transferable from its second position outside of the housing into the maintenance station by a translatory movement in a fourth direction perpendicular to the transmission plane and optionally in a fifth direction parallel to the direction of movement of the transmission element carrier when the transmission element carrier is moved between its first position and its second position, wherein the fourth direction in particular is opposed to the second direction. In such an arrangement, the storage station and the maintenance station may be arranged in a plane which is still parallel to the transmission plane, but offset in a direction perpendicular to the transmission plane, for example in the direction of the irradiation device of the apparatus for producing a three-dimensional work piece. Further, the storage station and the maintenance station may be arranged adjacent to each other and behind one another in the third direction or the fifth direction.

[0057] A first maintenance station may be arranged relative to the housing such that a used transmission element carrier, by means of the transfer system, is transferable from its second position outside of the housing into the first maintenance station by a translatory movement in a fifth direction parallel to the direction of movement of the transmission element carrier when the transmission element carrier is moved between its first position and its second position. Further, the transfer system may be configured to transfer a transmission element carrier from the first maintenance station to a second maintenance station and / or at least one storage station by a rotary movement about a rotational axis extending substantially perpendicular to the transmission plane. In such an arrangement, the storage station(s) and the maintenance stations may be arranged in a plane parallel to the transmission plane around the rotational axis.

[0058] The transfer system may also be configured to transfer a used transmission element carrier from its second position outside of the housing to a maintenance station by a pivoting movement about a first pivot axis extending substantially parallel to the transmission plane in a sixth direction. Further, the transfer system may be configured to transfer an exchange transmission element carrier from a storage station into its second position outside of the housing by a pivoting movement about a second pivot axis extending substantially parallel to the transmission plane in a seventh direction. The first and the second pivot axes may extend substantially parallel to each other. The seventh direction in particular may be opposed to the sixth direction. In such an arrangement, the storage station and the maintenance station may be arranged in an installation space saving manner adjacent to each other and behind one another in the third direction or the fifth direction.

[0059] In an alternative arrangement, a maintenance station and a storage station may be arranged on top of each other. Further, the maintenance station and the storage station may be rotatable about an axis extending parallel to the transmission plane so as to move each of the maintenance station and the storage station between a first state of operation and a second state of operation. In its first state of operation, the maintenance station may be arranged relative to the housing such that a used transmission element carrier, by means of the transfer system, is transferable from its first position into the maintenance station by a translatory movement in a fifth direction parallel to the direction of movement of the transmission element carrier when the transmission element carrier is moved between its first position and its second position. Thus, when the maintenance station is in its first state of operation and loaded with a used transmission element carrier, the transmission plane of the used transmission element carrier transferred into the maintance station coincides with the transmission plane of a transmission element carrier arranged in its first position.

[0060] Further, when the maintenance station is in its first state of operation, the second position may be arranged within the maintenance station. It is, however, also conceivable that the transfer of the used transmission element carrier between the first position and the maintenance station is effected via an "intermediate" second position.

[0061] Finally, when the maintenance station is in its first state of operation, the storage station typically also is in its first state of operation and arranged on top of or below the maintenance station. When the storage station is in its first state of operation and loaded with an exchange transmission element carrier, the transmission plane of the exchange transmission element carrier accommodated in the storage station is offset relative to the transmission plane of a transmission element carrier arranged in its first position and preferably also offset relative to the transmission plane of a used transmission element carrier accommodated in the maintenance station.

[0062] After transferring a used transmission element carrier into the maintenance station, the maintenance station and the storage station may be rotated about the axis extending parallel to the transmission plane so as to move each of the maintenance station and the storage station into the second state of operation.

[0063] In its second state of operation, the storage station may be arranged relative to the housing such that an exchange transmission element carrier, by means of the transfer system, is transferable from the storage station into the first position by a translatory movement in a third direction parallel to the direction of movement of the transmission element carrier when the transmission element carrier is moved from its second position into its first position. Thus, when the storage station is in its second state of operation and loaded with an exchange transmission element carrier, the transmission plane of the exchange transmission element carrier coincides with the transmission plane of a transmission element carrier arranged in its first position.

[0064] Further, when the storage station is in its second state of operation, the second position may be arranged within the storage station. It is, however, also conceivable that the transfer of the exchange transmission element carrier between the storage station and the first position is effected via an "intermediate" second position.

[0065] Finally, when the storage station is in its second state of operation, the maintenance station typically also is in its second state of operation and arranged on top of or below the storage station. When the maintenance station is in its second state of operation and loaded with a used transmission element carrier, the transmission plane of the used transmission element carrier accommodated in the maintenance station is offset relative to the transmission plane of a transmission element carrier arranged in its first position and preferably also offset relative the transmission plane of an exchange transmission element carrier accommodated in the storage station.

[0066] Preferred embodiments of the invention in the following are explained in greater detail with reference to the accompanying schematic drawings, in which:

[0067] Figure 1 shows an apparatus for producing a three-dimensional work piece which is equipped with a transmission element system, wherein a transmission element carrier of the transmission element system is arranged in a first position;

[0068] Figure 2 shows the apparatus of figure 1, wherein, however, the transmission element carrier of the transmission element system is arranged in a second position;

[0069] Figures 3 to 6 shows a first embodiment of a transmission element system;

[0070] Figures 7 to 9 shows a second embodiment of a transmission element system;

[0071] Figures 10 to 15 shows a third embodiment of a transmission element system;

[0072] Figure 16 shows a first arrangement of a storage station, a maintenance station and a transfer system for transferring a transmission element carrier of a transmission element system between its second position, the storage station and the maintenance station;

[0073] Figure 17 shows a second arrangement of a storage station, a maintenance station and a transfer system for transferring a transmission element carrier of a transmission element system between its second position, the storage station and the maintenance station;

[0074] Figure 18 shows a third arrangement of two storage stations, two maintenance stations and a transfer system for transferring a transmission element carrier of a transmission element system between its second position, the storage station and the maintenance station;

[0075] Figure 19 shows a fourth arrangement of a storage station, a maintenance station and a transfer system for transferring a transmission element carrier of a transmission element system between its second position, the storage station and the maintenance station; and

[0076] Figure 20 shows a fifth arrangement of a storage station, a maintenance station and a transfer system for transferring a transmission element carrier of a transmission element system between its second position, the storage station and the maintenance station.

[0077] Figures 1 and 2 show an apparatus 100 for producing a three-dimensional work piece by an additive layering process. The apparatus 10 comprises a process chamber 102 accommodating a carrier 103 (see figures 16 and 18) for receiving a raw material powder. During operation of the apparatus 100, raw material powder is applied onto the carrier 103 by means of a powder application device (not shown). The carrier 103 is designed to be displaceable in a vertical direction so that, with increasing construction height of a work piece, as it is built up in layers from the raw material powder on the carrier 103, the carrier 103 can be moved downwards in the vertical direction.

[0078] The apparatus 100 for producing a three-dimensional work piece further comprises an irradiation device 104 for selectively irradiating electromagnetic or particle radiation, in particular laser radiation onto the raw material powder applied onto the carrier in order to produce a work piece made of said raw material powder by an additive layer construction method. By means of the irradiation device 104, the raw material powder on the carrier 103 may be subjected to electromagnetic or particle radiation in a site selective manner in dependence on the desired geometry of the component that is to be produced. The irradiation device 104 comprises a radiation source which may comprise a diode pumped Ytterbium fiber laser emitting laser light at a wavelength of approximately 1070 to 1080 nm. The irradiation device 104 further comprises an optical unit for guiding and processing a radiation beam emitted by the radiation source. The optical unit may comprise a beam expander for expanding the radiation beam, a scanner and an object lens. Alternatively, the optical unit may comprise a beam expander including a focusing optic and a scanner unit. By means of the scanner unit, the position of the focus of the radiation beam both in the direction of the beam path and in a plane perpendicular to the beam path can be changed and adapted. The scanner unit may be designed in the form of a galvanometer scanner and the object lens may be an f- theta object lens.

[0079] The process chamber 102 is sealed against the ambient atmosphere, i.e. against the environment surrounding the process chamber 102. Further, the process chamber is provided with a gas inlet and a gas outlet (not shown) such that a gas, in particular an inert gas such as, for example, Argon or Nitrogen may be directed through the process chamber 102. The inert gas directed through the process chamber 102 establishes an inert gas atmosphere and purges particulate impurities from the process chamber 102. The gas is conveyed through the process chamber 102 by means of a suitable conveying device such as, for example, a pump or a blower (not shown). In a top wall thereof of which faces the irradiation device 104, the process chamber 102 is provided with a radiation beam opening 106 (see figures 16 and 18) which serves to allow a radiation beam emitted by the irradiation device 104 to enter an interior of the process chamber 102.

[0080] A transmission element system 10 is arranged between the process chamber 102 and the irradiation device 104. The transmission element system 10 comprises a housing 12 which is arranged so as to cover the radiation beam opening 106 provided in the process chamber 102. In particular, the housing 12 is sandwiched between between the top wall of the process chamber 102 and a bottom wall of the irradiation device 104. The transmission element system 10 further comprises a transmission element carrier 14 which is movable relative to the housing 12 between a first position shown in figure 1 and a second position shown in figure 2. The transmission element carrier 14 comprises a first end region 15a and a second end region 15b. Both end regions 15a, 15b of the transmission element carrier 14 are accommodated within the housing 12 when the transmission element carrier 14 is arranged in its first position. When, however, the transmission element carrier 14 is arranged in its second position, both end regions 15a, 15b of the transmission element carrier 14 are arranged outside of the housing 12, wherein the first end region 15a faces of the housing 12 and wherein the second end region 15b faces away from the housing 12.

[0081] In the embodiment of a transmission element system 10 shown in the figures, the transmission element carrier 14 is provided with a plurality of transmission elements 16 each of which is configured to allow the transmission of a radiation beam emitted by the irradiation device 104. Further, the housing 12 of the transmission element system 10 is arranged between the process chamber 102 and the irradiation device 104 in such a position that the transmission elements 16 are aligned with the radiation beam opening 106 provided in the top wall of the process chamber 102 in order to allow the transmission of the radiation beams emitted by the irradiation device 104 through the transmission elements 16 and the radiation beam opening 106 into the process chamber 102. Thus, the transmission element system 10 shown is particularly suitable for being employed in an apparatus 10 with an irradiation device 104 which is capable of emitting a plurality of radiation beams. In the embodiment of a transmission element system 10 shown in the figures, each transmission element 16 is designed in the form of a window and made of a glass material or a suitable polymer material.

[0082] The process chamber 102 is thermally and mechanically decoupled from the irradiation device 104, for example, with the aid of a support structure as described in EP 3 713 694 Al (not shown in the drawings). In order to achieve the thermal and mechanical decoupling of the process chamber 102 and the irradiation device 104, the process chamber 102 and the irradiation device 104 are independently attached to the support structure. Further, the housing 12 of the transmission element system 10 is thermally and mechanically decoupled from the process chamber 102 and the irradiation device 104. In order to achieve the thermal and mechanical decoupling of the housing 12, the housing 12 is also independently attached to the support structure.

[0083] The housing 12 is attached to the support structure by means of at least one fixation element (not shown). Preferably, the fixation element is configured to provide for a certain variability in a direction perpendicular to the transmission plane P and / or in (a) direction(s) parallel to the transmission plane T. As a result, alignment of the housing 12 and the hence the transmission element system 10 relativ to the support structure, the process chamber 102 and the irradiation device 104 is simplified. As becomes apparent from figures 17 and 17, the housing 12 and hence the transmission element carrier 14 with the transmission elements is arranged offset relative to the radiation beam opening 106 provided in the process chamber 102 in the direction of the irradiation device 104 such that the transmission elements 106 are arranged outside of an interior space of the process chamber 102.

[0084] In its first position shown in figure 1, the transmission element carrier 14 is accommodated in the housing 12 in such a position that radiation beams emitted by the irradiation device 104 can pass through the transmission elements 16 into the process chamber 102. In other words, when the transmission element carrier 14 is arranged in its first position, the transmission elements 16 are aligned with the radiation beam opening 106 provided in the process chamber 102 such that radiation beams can be transmitted through the transmission elements 16 and enter the process chamber 102 through the radiation beam opening 106. In its second position shown in figure 2, the transmission element carrier 14 is arranged outside of the housing 12. When the transmission element carrier 14 is arranged outside of the housing 12, the transmission elements 16 are no longer aligned with radiation beam opening 106 provided in the process chamber 102.

[0085] The transmission element system 10 further comprises a connecting system 18 which in figures 1 and 2 is illustrated only schematically, but which will be described in greater detail with reference to figures 10 to 14 below. The connecting system 18 is attached to the housing 12 either fixedly or releasably. The transmission element carrier 14 is configured to be releasably attached to the connecting system 18 in order to connect the transmission element carrier 14 to the housing 12. Thus, the connecting system 18 provides a releasable connection of the transmission element carrier 14 to the housing 12 which allows, on the one hand, a secure fixation of the transmission element carrier 14 to the housing 12, but, on the other hand, allows the transmission element carrier 14 to be released from the housing 12, for example for cleaning or for being exchanged.

[0086] At least one surface of the transmission element carrier 14 and / or at least one surface of the housing 12 may be configured to reflect laser radiation and / or thermal radiation which is emitted from the process chamber 102 during operation of the apparatus 100. In particular, at least a surface of the transmission element carrier 14 which faces the process chamber 102 when the transmission element carrier 14 is arranged in its first position is designed so as to reflect laser radiation and / or thermal radiation. Similarly, at least a surface of the housing 12 which faces the process chamber 102 is designed so as to reflect laser radiation and / or thermal radiation. It is, however, also conceivable that more than one surface or all surfaces of the transmission element carrier 14 and / or of the housing 12 is / are configured to reflect laser radiation and / or thermal radiation. The at least one reflective surface may be produced by a suitable surface treatment of surface coating.

[0087] In the following, a first embodiment of the transmission element system 10 will be described with reference to figure 3 to 6. The housing 12 of the transmission element system 10 comprises a bottom element 20 which faces an interior of the process chamber 102 when the transmission element system 10 is mounted in an apparatus 100 as shown in figures 1 and 2. Further, the housing 12 comprises a cover element 22 which faces away from the interior of the process chamber 102 when the transmission element system 10 is mounted in an apparatus 100 as shown in figure 1 and 2. In the apparatus 100 shown in figures 1 and 2, the cover element 22 of the transmission element system 10 faces the irradiation device 104. When being arranged in its first position, the transmission element carrier 14 is sandwiched between the bottom element 20 and the cover element 22 of the housing 12.

[0088] Each of the bottom element 20 and the cover element 22 is provided with an opening 24, 26 which is aligned with the transmission elements 16 when the transmission element carrier 14 is accommodated in the housing 12 in its first position. Thus, a radiation beam emitted by the irradiation device 104 can pass through the opening 26 of the cover element 22, one of the transmission elements 16 and finally the opening 24 of the bottom element 20 so as to finally enter the interior of the process chamber 102.

[0089] A first sealing element 28 is attached to the transmission element carrier 14 so as to surround the transmission elements 16 and serves to seal the transmission element carrier 14 against the housing. As becomes apparent from figure 5, the first sealing element 28 is accommodated in a groove formed in the transmission element carrier 14. In particular, the first sealing element 28 is attached to a surface of the transmission element carrier 14 which faces away from the process chamber 102. Thus, the first sealing element 28 seals the transmission element carrier 14 against the cover element 22 of the housing 12.

[0090] Further, a second sealing element 30 attached to the housing (see figures 16 and 18). The second sealing element 30 is attached to the cover element 22 of the housing 12, so as to surround the opening 26 provided in the cover element 22. The second sealing element 30 may be accommodated in a groove formed in the cover element 22 of the housing 12 and serves to seal the housing 12 against the irradiation device 104.

[0091] Moreover, a third sealing element 32 is attached to the housing (see figures 16 and 18). The third sealing element 32 is attached to the bottom element 20 of the housing 12 so as to surround the opening 26 provided in the bottom element 24. The third sealing element may may be accommodated in a groove formed in the bottom element 20 of the housing 12 and serves to seal the housing 12 against the process chamber 102.

[0092] As becomes apparent in particular from figures 4 and 5, the transmission element carrier 14 comprises a flange element 34 which is configured to abut against an end face 36 of the housing 12 when the transmission element carrier 14 is accommodated in the housing 12 in its first position. The flange element 34 is sealed against the end face 36 of the housing 12 by means of a fourth sealing element 37. The fourth sealing element 37 is attached to the flange element 34 and extends in a plane substantially perpendicular to the transmission plane T defined by the transmission elements 16.

[0093] As becomes apparent from figure 5, the thickness of transmission element carrier 14 in a direction perpendicular to the transmission plane T decreases in a direction of movement of the transmission element carrier 14 when the transmission element carrier 14 is moved from its second position into its first position. In figure 4, the direction of movement of the transmission element carrier 14 when being moved from its second position into its first position is indicated by arrow M. Further, the thickness of the cover element 22 of the housing 12 in a direction perpendicular to the transmission plane T increases in the direction of movement M of the transmission element carrier 14 when the transmission element carrier 14 is moved from its second position into its first position. To the contrary, the thickness of the bottom element 20, in the direction of movement M of the transmission element carrier 14 when the transmission element carrier 14 is moved from its second position into its first position, remains constant.

[0094] Thus, the transmission element carrier 14 has a wedge-shaped design, wherein a top surface 38 of the transmission element carrier 14 is inclined relative to the transmission plane T in order to provide for the decreasing thickness of the transmission element carrier 14 in the direction of movement M of the transmission element carrier 14 when the transmission element carrier 14 is moved from its second position into its first position. The cover element 22 of the housing 12 has a complementary wedge-shaped design, i.e. a bottom surface 40 of the cover element is inclined relative to the transmission plane T in order to provide for the increasing thickness of the cover element 22 in the direction of movement M of the transmission element carrier 14 when the transmission element carrier 14 is moved from its second position into its first position.

[0095] In the first embodiment of a transmission element system 10 shown in figures 3 to 6, a bottom surface 42 of the transmission element carrier 14 extends substantially parallel to the transmission plane T. To the contrary, the top surface 38 of the transmission element carrier 14 is inclined relative to the transmission plane T at an angle of 1 to 5° relative to transmission plane T. The bottom surface 40 of the cover element 22 which cooperates with the inclined top surface 38 of the transmission element carrier 14 also is inclined relative to the transmission plane T at an angle of 1 to 5°. Finally, also the first sealing element 28 which is attached to the top surface 38 of the transmission element carrier 14 also extends in a plane which is inclined relative to the transmission plane T at an angle of 1 to 5°.

[0096] In the first embodiment of a transmission element system 10 shown in figures 3 to 6, the transmission element carrier 14, when viewed in a top view, has a substantially rectangular shape. To the contrary, in the second embodiment of a transmission element system 10 shown in figures 7 to 9, the transmission element carrier 14, when viewed in a top view, has a trapezoidal shape. The second embodiment of a transmission element system 10 shown in figure 7 to 9 further differs from the first embodiment of figure 3 to 6 in that neither the transmission element carrier 14 for the cover element 22 has a wedge-shaped design. Instead, in the second embodiment of figures 7 to 9, the thickness of the bottom element 20 of the housing 12, the transmission element carrier 14 and the cover element 22 of the housing 12, in the direction of movement M of the transmission element carrier 14 when the transmission element carrier 14 is moved from its second position into its first position, remains constant.

[0097] The second embodiment of a transmission element system 10 shown in figure 7 to 9 might be equipped with a first sealing element 28 which is designed as the first sealing element 28 of the first embodiment according to figures 3 to 6. Such a first sealing element 28 then would be arranged in a plane substantially parallel to the transmission plane T. In the specific embodiment of figures 7 to 9, the first sealing element 28, however, comprises a first portion 28a and a second portion 28b. The first portion 28a is arranged in a plane substantially parallel to the transmission plane T. The second portion 28b, however, is bent upwards with respect to the first portion 28a so as to extend in a plane substantially perpendicular to the transmission plane T. Specifically, the second portion 28b of the first sealing element 28 is arranged in the second end region 15b of the transmission element carrier 14. Otherwise, the structure and the function of the second embodiment of a transmission element system 10 shown in figure 7 to 9 correspond to the structure and the function of the first embodiment of the transmission element system 10 according to figures 3 to 6.

[0098] The third embodiment of a transmission element system 10 shown in figure 10 to 15, differs from the first embodiment of figure 3 to 6 in that both the bottom element 20 and the cover element 22 of the housing 12 comprise a plurality of openings 24, 26 which are aligned with the transmission elements 16 of the transmission element carrier 14. Thus, for each transmission element 16, the housing 12 is provided with an associated pair of openings 24, 26. Further, the transmission element system 10 comprises a plurality of second sealing elements 30 as well as a plurality of third sealing elements 32. Each second sealing element 30 surrounds one opening 26 provided in the cover element 22 and each third sealing element 32 surrounds one opening 24 provided in the bottom element 20.

[0099] Further, figures 10 to 15 show details of the connecting system 18 which serves to connect the transmission element carrier 14 to the housing 12. It has to be noted that the first and the second embodiment of the transmission element system 10 as shown in figures 3 to 6 and 79, respectively, may also be equipped with a connecting system 18 as depicted in figures 10 to 15. Further, also other features which herein are described with reference to a specific embodiment, might be provided in other embodiments. For example, a transmission element carrier 14 might be wedge- shaped when viewed in a side view and, in addition thereto, might have a trapezoidal shape when viewed in a top view.

[0100] Figure 10 shows the transmission element system 10 with the transmission element carrier 14 being arranged in its first position, whereas figure 11 shows the transmission element system 10 with the transmission element carrier 14 being arranged in its second position. As becomes apparent from a comparison of figures 10 and 11, the connecting system 18 is movable relative to the housing 12 so as to allow a sliding movement of the transmission element carrier 14 relative to the housing 12 between the first and the second position along a longitudinal axis L of the housing 12 and parallel to a transmission plane T. Thus, the transmission element carrier 14 can be displaced relative to the housing 12 between its first position and its second position in a controlled manner while being connected to the housing 12 via the connecting system 18.

[0101] As shown in particular in figures 11 to 13, the connecting system 18 comprises a first supporting surface 44 which is configured to support the first end region 15a of the transmission element carrier 14 and a second supporting surface 46 which is configured to support the second end region 15b of the transmission element carrier. The second supporting surface 46 is spaced from the first supporting surface 44 along the longitudinal axis L of the housing 12. The first and the second supporting surface 44, 46 support the transmission element carrier 14 in its first position and in its second position. Thus, the connecting system 18 still securely holds the transmission element carrier 14 also when the transmission element carrier 14 is arranged in its second position outside of the housing 12.

[0102] The connecting system 18 further comprises guide rails 48, 50 which serve to guide the movement of the transmission element carrier 14 relative to the housing 12 between its first position and its second position. The guide rails 48, 50 extend parallel to the longitudinal axis L of the housing 12 and parallel to each other between the first supporting surface 44 and the second supporting surface 46. Further, the guide rails 48, 50 extend adjacent to opposing sidewalls of the housing 12 which are defined by corresponding sidewalls of the bottom element 20 and the cover element 22.

[0103] Two latching elements 52, 54 are provided which serve to releasably latch the transmission element carrier 14 in its first position. In particular, the latching elements 52, 54 are rotatable about an axis of rotation which extends parallel to the longitudinal axis L of the housing. Each latching element 52, 54 is attached to a mounting element 56, 58 which connects the guide rails 48, 50 of the connecting system 18 to the housing 12. When the latching elements 52, 54 are arranged in their closing position as shown in figure 10, they interact with the first supporting surface 44 of the connecting system 18 and thus prevent a sliding movement of the connecting system 18 and hence the transmission element carrier 14 relative to the housing 12. To the contrary, when the latching elements 52 are arranged in their open position as shown in figures 11 to 13, they no longer abut against the first supporting surface 44 of the connecting system 18. Consequently, the connecting system 18 and the transmission element carrier 14 connected thereto can be slighted out of the housing 12. The transmission element system 10 further comprises a cooling device 56 which serves to call the housing 12 and the transmission element carrier 14 when the transmission element carrier 14 is accommodated in the housing 12 in its first position. In the embodiment of a transmission element system 10 shown in figures 10 to 15, the cooling device 56 is defined by the guide rails 48, 50 of the connecting system 18 which are made of a metal material having a high thermal conductivity, such as aluminum.

[0104] Further, the transmission element system 10 comprise as thermal expansion compensation arrangement 58 which serves to compensate a thermal expansion of the housing 12 and / or the transmission element carrier 14 when the transmission element carrier 14 is accommodated in the housing 12 in its first position.

[0105] Specifically, the thermal expansion compensation arrangement 58 serves to maintain a correct positioning of the transmission element carrier 14 relative to the housing 12 even in case the transmission element carrier 14 and / or the housing 12 is subject to a deformation due to thermal expansion.

[0106] The thermal expansion compensation arrangement 58 comprises a first abutting device 60 provided on the housing 12 (only schematically illustrated in figures 10 to 15) which is interacts with a second abutting device 62 provided on the transmission element carrier 14 when the transmission element carrier 14 is accommodated in the housing 12 in its first position. A biasing element 64 which is designed in the form of a spring biases the second abutting device 62 against the first abutting device 60 and thus serves to maintain the first and the second abutting devices 60, 62 in contact even in case of a thermal deformation of the housing 12 and / or the transmission element carrier 14.

[0107] The transmission element system 10 further comprises a first shutter 66 which is movable between an active position and a stored position, see in particular figures 11 and 14 which show the first shutter 66 in its active position. In its active position, the first shutter 66 covers and hence protects the transmission elements 16. When the first shutter 66 is arranged in its stored position, is wound on a roller 68 and the transmission elements 16 are exposed. The first shutter 66 is made from a metal foil, in particular a stainless steel foil.

[0108] The first shutter 66 comprises an automatic activation mechanism 70 which is configured to deploy the first shutter 66 from its stored position into its active position when the transmission element carrier 14 is moved from its first position into its second position. Thus, the first shutter 66 is automatically activated and protects the transmission elements 16 as soon as the transmission element carrier 14 is moved out of the housing 12. The automatic activation mechanism 70 ensures that the first shutter is "entrained" with the movement of the transmission element carrier 14 when the transmission element carrier 14 is moved from its first position into its second position and hence deployed so as to cover the transmission elements 16. When the transmission element carrier 14 has reached its second position, protrusions 72, 74 which are connected to the first shutter 66 are received in recesses 76, 78 provided in first end region of the transmission element carrier 14 as shown in figure 12 so as to lock the first shutter 66 in its deployed position. Thus, thus the first shutter 66 remains in its deployed position even when the transmission element carrier 14 is released from the connecting system 18 as shown in figure 13.

[0109] The transmission element system 10 further comprises a second shutter 80 which is movable between an active position and a stored position, see in particular figures 11 and 14 which show the second shutter 80 in its active position. In its active position, the second shutter 80 extends within the housing 12 in place of the transmission element carrier 14. Thus, second shutter 80, when being arranged in its active position, covers the openings 24 provided in the bottom element 20 of the housing 12 and the openings provided in the cover element 22 of the housing 12. Consequently, the second shutter 80 separates the process chamber 102 from the irradiation device 104 and hence protect the components, in particular the optical components of the irradiation device 104 from being contaminated by impurities present in the process chamber 102. When the second shutter 80 is arranged in its stored position, is wound on a roller 81. Like the first shutter 66, also the second shutter 80 is made from a metal foil, in particular a stainless steel foil.

[0110] The second shutter 80 also comprises an automatic activation mechanism 82 which is configured to deploy the second shutter 80 from its stored position into its active position when the transmission element carrier 14 is moved from its first position into its second position. Thus, the second shutter 80 is also automatically activated and so as to separate the process chamber 102 from the irradiation device 104 as soon as the transmission element carrier 14 is moved out of the housing 12. The automatic activation mechanism 82 ensures that the second shutter 80 is "entrained" with the movement of the transmission element carrier 14 when the transmission element carrier 14 is moved from its first position into its second position and hence deployed so as to separate the process chamber 102 from the irradiation device 104. When the transmission element carrier 14 has reached its second position, protrusions 84, 86 which are connected to the second shutter 80 are received in recesses 88, 90 provided in first end region of the transmission element carrier 14 as shown in figure 12 so as to lock the second shutter 80 in its deployed position. Thus, thus the second shutter 80 remains in its deployed position even when the transmission element carrier 14 is released from the connecting system 18 as shown in figure 13.

[0111] As becomes apparent from figures 16 to 20, the apparatus 100 further comprises at least one storage station 108 configured to accommodate at least one ready-to-use exchange transmission element carrier 14 which can be connected to the connecting system 18 of the transmission element system 10 and used at any time on request. Further, the apparatus comprises at least one maintenance station 110 which is configured to accommodate a used transmission element carrier 14. In the maintenance station 110, a used transmission element carrier 14 may be inspected, cleaned and / or repaired in order to prepare the used transmission element carrier 14 for being reused in the transmission element system 10. In particular, the maintenance station 110 is equipped with sensors (not shown) for testing and inspecting the dimensions, the surface quality, the electrical properties and other relevant parameters of the transmission elements 16. The data detected by the sensors are evaluated by a control device 111.

[0112] Moreover, the apparatus 100 comprises a transfer system 112 which is operated under the control of the control device 111. Under the control of the control device 111, the transfer system 112 may automatically transfer the transmission element carrier 14 between different positions. For example, the transfer system may transfer a used transmission element carrier 14 from its first position within the housing 12 into its second position outside of the housing 12, e.g. after a build job for producing a three dimensional work piece is completed or in response to a signal requesting an exchange of the transmission element carrier 14 which is received by the control device 111. The transfer system 112 may also transfer the transmission element carrier 14 into the maintenance station 110. In the arrangements shown in figures 16 to 19, the second position outside of the housing is an "intermediate" position the transmission element carrier 14 assumes after being removed from its first position and before being further transferred to the maintenance station 110.

[0113] Further, under the control of the control device 111, the transfer system 112 may transfer an exchange transmission element carrier 14 from the storage station 108 into its first position within the housing 12. In the arrangements shown in figures 16 to 19, the transfer of the exchange transmission element carrier 14 between the storage station and the first position within the housing is effected via the "intermediate" second position outside of the housing. In other words, an exchange transmission element carrier 14 first is transferred from the storage station 108 into its second position outside of the housing 12 and then further into its first position within the housing 12.

[0114] Further, again under the control of the control device 111, the transfer system 112 may transfer a used transmission element carrier 14, after being processed in the maintenance station 110 and being considered to be suitable for reuse, from the maintenance station 110 to the storage station 108. The transfer system 112 may comprise robot arms, conveyor belts or other automatic mechanisms (not shown) which provide for the transfer of the transmission element carriers 14 between the housing 12 of the transmission element system 10, the storage station 108 and the maintenance station 110.

[0115] In addition to the storage station 108 and the maintenance station 110, a defective unit storage station (not shown) may be provided which is configured to accommodate at least one exchange transmission element carrier 14 which, by the control unit 111, is considered to be defective and hence no longer usable in the transmission element system 10. The transfer system 112, under the control of the control device 111, may also transfer a used transmission element carrier 14 from the maintenance station 110 to the defective unit storage station.

[0116] In the exemplary arrangement of figure 16, which shows a top view of the apparatus 100, the storage station 108 is arranged relative to the housing 12 such that an exchange transmission element carrier 14, by means of the transfer system, can be transferred from the storage station 108 into its second position outside of the housing 12 by a translatory movement in a first direction DI parallel to the transmission plane T and perpendicular to the direction of movement of the transmission element carrier 14 when the transmission element carrier is moved between its second position and its first position. Further, the maintenance station 110 is arranged relative to the housing 12 such that a used transmission element carrier 14, by means of the transfer system 112, can be transferred from its second position outside of the housing 12 into the maintenance station 110 by a translatory movement in the first direction DI parallel to the transmission plane T and perpendicular to the direction of movement of the transmission element carrier 14 when the transmission element carrier 14 is moved between its second position and its first position. Thus, the storage station 108 and the maintenance station 110 are arranged in a plane parallel to the transmission plane T and adjacent to opposing sides of a transmission element carrier 14 being arranged in its second position outside of the housing 12.

[0117] In the exemplary arrangement of figure 17, which shows a side view of the apparatus 100, the storage station 108 is arranged relative to the housing 12 such that an exchange transmission element carrier 14, by means of the transfer system 112, can be transferred from the storage station 108 into its second position outside of the housing 12 by a translatory movement in a second direction D2 perpendicular to the transmission plane T and then further in a third direction D3 parallel to the direction of movement M of the transmission element carrier 14 when the transmission element carrier 14 is moved from its second position into its first position. Moreover, the maintenance station 110 is arranged relative to the housing 12 such that a used transmission element carrier 14, by means of the transfer system 112, can be transferred from its second position outside of the housing 12 into the maintenance station 110 by a translatory movement in a fourth direction D4 perpendicular to the transmission plane T and then further in a fifth direction D5 parallel to the direction of movement of the transmission element carrier 14 when the transmission element carrier 14 is moved between its first position and its second position. The fourth direction D4 is opposed to the second direction D2. The storage station 108 and the maintenance station 110 are arranged in a plane which is still parallel to the transmission plane T, but offset in a direction perpendicular to the transmission plane T in the direction of the irradiation device 104. Further, the storage station 108 and the maintenance station 110 are arranged adjacent to each other and behind one another in the third direction D3 or the fifth direction D5.

[0118] In the exemplary arrangement of figure 18, which shows a top view of the apparatus 100, the apparatus 100 comprises a first and a second storage station 108a, 108b as well as a first and a second maintenance station 110a, 110b. The first maintenance station 110a is arranged relative to the housing 12 such that a used transmission element carrier 14, by means of the transfer system 112, can be transferred from its second position outside of the housing 12 into the first maintenance station 110 by a translatory movement in the fifth direction D5 parallel to the direction of movement of the transmission element carrier 14 when the transmission element carrier 14 is moved between its first position and its second position. The transfer system 112 is configured to transfer a transmission element carrier 14 from the first maintenance station 110a to a second maintenance station 110b or one of two storage stations 108a, 108b by a rotary movement about a rotational axis R extending substantially perpendicular to the transmission plane T. Similarly, a transfer of an exchange transmission element carrier 14 from the first or the second storage station 108a, 108b into its second position outside of the housing 12 is also achieved by a rotary movement of the transmission element carrier 14 about the rotational axis R. In the arrangement of figure 18, the storage stations 108a, 108b and the maintenance stations 110a, 110b are arranged in a plane parallel to the transmission plane T around the rotational axis R.

[0119] In the exemplary arrangement of figure 19, which shows a side view of the apparatus 100, the transfer system 112 is configured to transfer a used transmission element carrier 14 from its second position outside of the housing 12 to a maintenance station 110 by a pivoting movement about a first pivot axis Pl extending substantially parallel to the transmission plane T in a sixth direction D6. Further, the transfer system 112 is configured to transfer an exchange transmission element carrier 14 from a storage station 108 into its second position outside of the housing 12 by a pivoting movement about a second pivot axis P2 extending substantially parallel to the transmission plane T in a seventh direction D7. The first and the second pivot axes Pl, P2 extend substantially parallel to each other. The seventh direction D7 is opposed to the sixth direction D7. In the arrangement of figure 19, the storage station 108 and the maintenance station 110 are arranged in an installation space saving manner adjacent to each other and behind one another in the third direction D3 or the fifth direction D5.

[0120] In the arrangement of Fig. 20, a maintenance station 110 and a storage station 108 are arranged on top of each other. Further, the maintenance station 110 and the storage station 108 are rotatable about an axis R extending parallel to the transmission plane T so as to move each of the maintenance station 110 and the storage station 108 between a first state of operation and a second state of operation. In its first state of operation shown in Fig. 20, the maintenance station 110 is arranged relative to the housing 12 such that a used transmission element carrier 14, by means of the transfer system 112, can be transferred from its first position into the maintenance station 110 by a translatory movement in a fifth direction D5 parallel to the direction of movement of the transmission element carrier 14 when the transmission element carrier 14 is moved between its first position and its second position. Thus, when the maintenance station 110 is in its first state of operation and loaded with a used transmission element carrier 14, the transmission plane of the used transmission element carrier 14 transferred into the maintenance station 110 coincides with the transmission plane T of a transmission element carrier 14 arranged in its first position.

[0121] Further, when the maintenance station 110 is in its first state of operation, the second position is arranged within the maintenance station 110. Thus, in the arrangement of Fig. 20, the transfer of the used transmission element carrier 14 between the first position and the maintenance station 110 no longer is effected via an "intermediate" second position. Instead, the used transmission element carrier 14 is directly transferred from its first position within the housing 12 into its second position within the maintenance station 110.

[0122] When the maintenance station 110 is in its first state of operation, the storage station 108 also is in its first state of operation. In the arrangement of Fig. 20, the storage station 108 is arranged on top of the maintenance station 110 when both the storage station 108 and the maintenance station 110 are arranged in their first state of operation. It is, however, also conceivable that the storage station 108 is arranged below the maintenance station 110 when both the storage station 108 and the maintenance station 110 are arranged in their first state of operation. In any case, when both the storage station 108 and the maintenance station 110 are arranged in their first state of operation, the transmission plane of the exchange transmission element carrier 14 accommodated in the storage station 108 is offset relative to the transmission plane T of a transmission element carrier 14 arranged in its first position and also offset relative to the transmission plane of a used transmission element carrier 14 accommodated in the maintenance station 110.

[0123] After transferring a used transmission element carrier 14 into the maintenance station 110, the maintenance station 110 and the storage station 108, by means of the transfer system 112 are rotated about the axis R so as to move both the maintenance station 110 and the storage station 108 into the second state of operation. In the arrangement of Fig. 20, the storage station 108 is arranged below the maintenance station 110 when both the storage station 108 and the maintenance station 110 are arranged in their second state of operation. It is, however, also conceivable that the storage station 108 is arranged on top of the maintenance station 110 when both the storage station 108 and the maintenance station 110 are arranged in their second state of operation. In any case, in its second state of operation, the storage station 108 is arranged relative to the housing 12 such that an exchange transmission element carrier 14, by means of the transfer system 112, can be transferred from the storage station 108 into the first position by a translatory movement in a third direction D3 parallel to the direction of movement of the transmission element carrier 14 when the transmission element carrier 14 is moved from its second position into its first position. Thus, when the storage station 108 is in its second state of operation and loaded with an exchange transmission element carrier 14, the transmission plane of the exchange transmission element carrier 14 coincides with the transmission plane T of a transmission element carrier 14 arranged in its first position.

[0124] Further, when the storage station 108 is in its second state of operation, the second position may be arranged within the storage station 108. Thus, in the arrangement of Fig. 20, the transfer of the exchange transmission element carrier 14 between the storage station 110 and the first position no longer is effected via an "intermediate" second position. Instead, the exchange transmission element carrier 14 is directly transferred from the second position within the storage station 108 into its first position within the housing 12.

[0125] When the storage station 108 is in its second state of operation, the maintenance station 110 also is in its second state of operation and arranged on top of or below the storage station. In the arrangement of Fig. 20, the maintenance station 110 is arranged on top of the storage station 108 when both the storage station 108 and the maintenance station 110 are arranged in their second state of operation. It is, however, also conceivable that the maintenance station 110 is arranged below the storage station 108 when both the storage station 108 and the maintenance station 110 are arranged in their second state of operation. In any case, when both the storage station 108 and the maintenance station 110 are arranged in their second state of operation, the transmission plane of the used transmission element carrier 14 accommodated in the maintenance station 110 is offset relative to the transmission plane T of a transmission element carrier 14 arranged in its first position and also offset relative the transmission plane of an exchange transmission element carrier 14 accommodated in the storage station 108.

Claims

Claims1. A transmission element system (10) for use in an apparatus (100) for producing a three-dimensional work piece, the transmission element system (10) comprising:- a housing (12) which is configured to be arranged so as to cover a radiation beam opening (106) provided in a process chamber (102) of the apparatus (100) for producing a three-dimensional work piece;- a transmission element carrier (14) which comprises at least one transmission element (16) configured to allow the transmission of a radiation beam emitted by an irradiation device (104) of the apparatus (100) for producing a three-dimensional work piece, wherein the transmission element carrier (14) is movable relative to the housing (12) between a first position, wherein the transmission element carrier (14) is accommodated in the housing (12) such that a radiation beam emitted by the irradiation device (104) passes through the at least one transmission element (16) of the transmission element carrier (14) into the process chamber (12), and a second position, wherein the transmission element carrier (14) is arranged outside of the housing (12); and- a connecting system (18) attached to the housing (12), wherein the transmission element carrier (14) is configured to be releasably attached to the connecting system (18) in order connect the transmission element carrier (14) to the housing (12).

2. The transmission element system (10) of claim 1, wherein:- the connecting system (10) is movable relative to the housing (12) so as to allow a sliding movement of the transmission element carrier (14) relative to the housing (12) between the first and the second position along a longitudinal axis (L) of the housing (12) and / or parallel to a transmission plane (T) defined by the at least one transmission element (16).

3. The transmission element system (10) of claim 1 or 2, wherein the connecting system (18) comprises at least one of:- a first supporting surface (44) configured to support a first end region (15a) of the transmission element carrier (14);- a second supporting surface (46) which is spaced from the first supporting surface (44) along the longitudinal axis (L) of the housing (12) and configured to support a second end region (15b) of the transmission element carrier (14) which is arranged opposed of the first end region (15a);- at least one guide rail (48, 50) which preferably extends between the first supporting surface (44) and the second supporting surface (46) and / or which preferably extends substantially parallel to the longitudinal axis (L) of the housing (12) and / or which preferably extends adjacent to a sidewall of the housing (12), wherein the sidewall of the housing (12) extends substantially parallel to the longitudinal axis (L) of the housing (12).

4. The transmission element system (10) of any one of claims 1 to 3, further comprising at least one latching element (52, 54) configured to releasably latch the transmission element carrier (14) in its first position.

5. The transmission element system (10) of any one of claims 1 to 4, further comprising at least one of:- a cooling device (56) configured to cool the housing (12) and / or the transmission element carrier (14) when the transmission element carrier (14) is accommodated in the housing (12) in its first position; and / or- a thermal expansion compensation arrangement (58) configured to compensate a thermal expansion of the housing (12) and / or the transmission element carrier (14) when the transmission element carrier (14) is accommodated in the housing (12) in its first position, wherein the thermal expansion compensation arrangement (58) in particular comprises a first abutting device (60) provided on the housing (12) and / or the connecting system (18) which is configured to interact with a second abutting device (62) provided on the transmission element carrier (14) when the transmission element carrier (14) is accommodated in the housing (12) in its first position, and a biasing element (64) which biases the second abutting device (62) against the first abutting device (60) when the transmission element carrier (14) is accommodated in the housing (12) in its first position.

6. The transmission element system (10) of any one of claims 1 to 5, wherein the housing (12) comprises:- a bottom element (20) which is configured to face an interior of the process chamber (102) when the transmission element system (10) is mounted in an apparatus (100) for producing a three-dimensional work piece; and / or- a cover element (22) which is configured to face away from the interior of the process chamber (102) when the transmission element system (10) is mounted in an apparatus (100) for producing a three-dimensional work piece, wherein the transmission element carrier (14), when being arranged in its first position, preferably is sandwiched between the bottom element (20) and the cover element (22) of the housing (12).

7. The transmission element system (10) of claim 6, wherein the bottom element (22) is provided with at least one opening (24) which is aligned with the at least one transmission element (16) when the transmission element carrier (14) is accommodated in the housing (12) in its first position, and / or wherein the cover element (20) is provided with at least one opening (26) which is aligned with the at least one transmission element (16) when the transmission element carrier (14) is accommodated in the housing (12) in its first position.

8. The transmission element system (10) of any one of claims 1 to 7, further comprising at least one of:- a first sealing element (28) which is attached to the transmission element carrier (14) so as to surround the at least one transmission element (16) and which is configured seal the transmission element (16) against the housing (12), in particular the cover element (22) of the housing (12);- at least one second sealing element (30) which is configured seal the housing (12), in particular the cover element (22) of the housing (12), against the irradiation device (104) when the transmission element system (10) is mounted in an apparatus (100) for producing a three-dimensional work piece, wherein the second sealing element (30) in particular is attached to the cover element (22) of the housing (12) so as to surround the at least one opening (26) provided in the cover element (22); and- at least one third sealing element (32) which is configured seal the housing (12), in particular the bottom element (20) of the housing (12), against the process chamber (102) when the transmission element system (10) is mounted in an apparatus (100) for producing a three-dimensional work piece, wherein the third sealing element (32) in particular is attached to the bottom element (20) of the housing (12) so as to surround the at least one opening (24) provided in the bottom element (20).

9. The transmission element system (10) of any one of claims 1 to 8, wherein the first sealing element (28) is arranged in a plane substantially parallel to the transmission plane (T) defined by the at least one transmission element (16), or wherein the first sealing element (28) comprises a first portion (28a) and a second portion (28b), wherein the first portion (28a) a arranged in a plane substantially parallel to the transmission plane (T) defined by the at least one transmission element (16) and wherein the second portion (28b) a arranged in a plane substantially perpendicular to the transmission plane (T) defined by the at least one transmission element (16).

10. The transmission element system (10) of any one of claims 1 to 9, wherein the transmission element carrier (14) comprises a flange element (34) configured to abut against an end face (36) of the housing (12) when the transmission element carrier (14) is accommodated in the housing (12) in its first position, wherein the flange element (34) in particular is sealed against the end face (36) of the housing (12) by means of a fourth sealing element (37), the fourth sealing element (37) in particular being attached to the flange element (34) and / or extending in a plane substantially perpendicular to the transmission plane (T) defined by the at least one transmission element (16).

11. The transmission element system (10) of any one of claims 1 to 10, wherein:- a thickness of the transmission element carrier (14) in a direction perpendicular to the transmission plane (T) defined by the at least one transmission element (16) decreases in a direction of movement of the transmission element carrier (14) when the transmission element carrier (14) is moved from its second position into its first position; and / or- a thickness of the bottom element (20) and / or the cover element (22) of the housing (12) in a direction perpendicular to the transmission plane (T) defined by the at least one transmission element (16) increases in a direction of movement of the transmission element carrier (14) when the transmission element carrier (14) is moved from its second position into its first position.

12. The transmission element system (10) of any one of claims 1 to 11, wherein:- the transmission element carrier (14), when viewed in top view, has a trapezoidal shape; and / or- the bottom element (20) and / or the cover element (22) of the housing (12), when viewed in top view, has / have a trapezoidal shape.

13. The transmission element system (10) of any one of claims 1 to 12, further comprising at least one of:- a first shutter (66) which is configured to be moved between an active position, wherein the first shutter (66) covers the at least one transmission element (16), and a stored position, wherein the at least one transmission element (16) is exposed, the first shutter (66) in particular comprising an automatic activation mechanism (70) which is configured to deploy the first shutter (66) from its stored position into its active position when the transmission element carrier (14) is moved from its first position into its second position;- a second shutter (80) which is configured to be moved between an active position, wherein the second shutter (80) extends within the housing (12) in place of the transmission element carrier (14), and a stored position, the second shutter (80) in particular comprising an automatic activation mechanism (82) which is configured to deploy the second shutter (80) from its stored position into its active position when the transmission element carrier (14) is moved from its first position into its second position.

14. An apparatus (100) for producing a three-dimensional work piece, the apparatus (10) comprising:- a process chamber (102),- a carrier (103) configured to receive a raw material powder,- an irradiation device (104) configured to selectively irradiate electromagnetic or particle radiation onto the raw material powder on the carrier (103) in order to produce a work piece made of said raw material powder by an additive layer construction method, and- a transmission element system (10) according to any one of claims 1 to 13.

15. The apparatus (100) of claim 14, wherein:- the housing (12) of the transmission element system (10) is arranged between the process chamber (102) and the irradiation device (104) such that the at least one transmission element (16) is aligned with the radiation beam opening (106) provided in the process chamber (102) in order to allow the transmission of the radiation beam emitted by the irradiation device (104) through the transmission element (16) and the radiation beam opening (106)into the process chamber; and / or- the process chamber (102) is thermally and / or mechanically decoupled from the irradiation device (104); and / or- the housing (12) of the transmission element system (10) is thermally and / or mechanically decoupled from the process chamber (102) and / or the irradiation device (104).

16. The apparatus (100) of claim 15, wherein the at least one transmission element (16), is arranged offset relative to the radiation beam opening (106) provided in the process chamber (102) in the direction of the irradiation device (104) such that the at least one transmission element (16) is arranged outside of an interior space of the process chamber (102) delimited by the process chamber wall ().17 The apparatus (100) of any one of claims 14 to 16, further comprising at least one of:- at least one storage station (108) configured to accommodate at least one exchange transmission element carrier (14);- at least one maintenance station (110) configured to accommodate a used transmission element carrier (14);- a transfer system (112) for automatically transferring the transmission element carrier between different positions, wherein the transfer system (112) in particular is configured to transfer a used transmission element (16) from its first position within the housing (12) into its second position outside of the housing (12) and / or into the maintenance station (110); and / or wherein the transfer system (112) in particular is configured to transfer an exchange transmission element carrier (14) from the storage station (108) into its first position within the housing (12), preferably via its second position outside of the housing (12); and / or wherein the transfer system (112) in particular is configured to transfer a used transmission element carrier (14), preferably after being processed in the maintenance station (110), from the maintenance station (110) to the storage station (108).

18. The apparatus (100) of claim 17, wherein:- a storage station (108) is arranged relative to the housing (12) such that an exchange transmission element carrier (14), by means of the transfer system (112), is transferable from the storage station (108) into its second position outside of the housing (12) by a translatory movement in a first direction (DI) parallel to the transmission plane (T) and perpendicular to the direction of movement of thetransmission element carrier (14) when the transmission element carrier (14) is moved between its second position and its first position; and / or- a maintenance station (110) is arranged relative to the housing (12) such that a used transmission element carrier (14), by means of the transfer system (112), is transferable from its second position outside of the housing (12) into the maintenance station (110) by a translatory movement in the first direction (DI) parallel to the transmission plane (T) and perpendicular to the direction of movement of the transmission element carrier (14) when the transmission element carrier (14) is moved between its second position and its first position.

19. The apparatus (100) of claim 17 or 18, wherein:- a storage station (108) is arranged relative to the housing (12) such that an exchange transmission element carrier (14), by means of the transfer system (112), is transferable from the storage station (108) into its second position outside of the housing (12) by a translatory movement in a second direction (D2) perpendicular to the transmission plane (T) and optionally in a third direction (D3) parallel to the direction of movement of the transmission element carrier (14) when the transmission element carrier (14) is moved from its second position into its first position; and / or- a maintenance station (110) is arranged relative to the housing (12) such that a used transmission element carrier (14), by means of the transfer system (112), is transferable from its second position outside of the housing (12) into the maintenance station (110) by a translatory movement in a fourth direction (D4) perpendicular to the transmission plane (T) and optionally in a fifth direction (D5) parallel to the direction of movement of the transmission element carrier (14) when the transmission element carrier (14) is moved between its first position and its second position, wherein the fourth direction (D4) in particular is opposed to the second direction (D2).

20. The apparatus (100) of any one of claims 17 to 19, wherein:- a first maintenance station (110) is arranged relative to the housing (12) such that a used transmission element carrier (14), by means of the transfer system (112), is transferable from its second position outside of the housing (12) into the maintenance station (110) by a translatory movement in a fifth direction (D5) parallel to the direction of movement of the transmission element carrier (14) when thetransmission element carrier (14) is moved between its first position and its second position; and / or- the transfer system (112) is configured to transfer a transmission element carrier (14) from the first maintenance station (110) to a second maintenance station (110) and / or at least one storage station (108) by a rotary movement about a rotational axis (R) extending substantially perpendicular to the transmission plane (T).

21. The apparatus (100) of any one of claims 17 to 20, wherein:- the transfer system (112) is configured to transfer a used transmission element carrier (14) from its second position outside of the housing (12) to a maintenance station (110) by a pivoting movement about a first pivot axis (Pl) extending substantially parallel to the transmission plane (T) in a sixth direction (D6); and / or- the transfer system (112) is configured to transfer an exchange transmission element carrier (14) from a storage station into its second position outside of the housing (12) by a pivoting movement about a second pivot axis (P2) extending substantially parallel to the transmission plane (T) in a seventh direction (D7), wherein the first and the second pivot axes (Pl, P2) in particular extend substantially parallel to each other and / or wherein the seventh direction (D7) in particular is opposed to the sixth direction (D6).

22. The apparatus (100) of any one of claims 17 to 21, wherein:- a maintenance station (110) and a storage station (108) are arranged on top of each other and rotatable about an axis (R) extending parallel to the transmission plane (T) so as to move each of the maintenance station (110) and the storage station (108) between a first state of operation and a second state of operation; wherein:- the maintenance station (110), in its first state of operation, is arranged relative to the housing (12) such that a used transmission element carrier (14), by means of the transfer system (112), is transferable from its first position into the maintenance station (110) by a translatory movement in a fifth direction (D5) parallel to the direction of movement of the transmission element carrier (14) when the transmission element carrier (14) is moved between its first position and its second position, wherein the second position in particular is arranged within the maintenance station (110) when the maintenance station (100) is in its first state of operation; and / or- the storage station (108), in its second state of operation, is arranged relative to the housing (12) such that an exchange transmission element carrier (14), by means of the transfer system (112), is transferable from the storage station (108) into the first position by a translatory movement in a third direction (D3) parallel to the direction of movement of the transmission element carrier (14) when the transmission element carrier (14) is moved from its second position into its first position, wherein the second position in particular is arranged within the storage station (108) when the storage station (108) is in its second state of operation.

Images