Method, device, and apparatus for controlling an irradiation beam

Abstract

A method of controlling an irradiation beam to irradiate a raw material powder layer in an additive manufacturing process for producing a three-dimensional workpiece, comprising the steps of depositing said layer of raw material powder on a carrier and / or on a preceding material layer on the carrier using a layer deposition mechanism, and controlling the irradiation beam to irradiate at least a portion of the raw material powder layer within an irradiation area when a distance between the irradiation area and the layer deposition mechanism is greater than a threshold distance, where the threshold distance is determined by (i) a moving speed of the layer deposition mechanism and (ii) a gas flow speed v above the raw material powder layer. g A method is described that includes the steps of:

Description

Technical Field

[0001] The present invention generally relates to methods, devices, and apparatuses for controlling an irradiation beam in additive layer manufacturing.

Background Art

[0002] In the layer manufacturing method, work pieces are manufactured layer by layer by creating a series of solidified and interconnected work piece layers. These processes are distinguished by the raw material type and / or the method of solidifying the raw material to manufacture the work piece.

[0003] For example, powder bed fusion is a type of additive process that can process powdery raw materials, specifically metals and / or ceramics, into three-dimensional work pieces with complex shapes. For this purpose, a layer of raw material powder is applied onto a carrier and selectively irradiated, for example, with electron or laser radiation, depending on the desired geometry of the work piece to be manufactured. The radiation penetrating the powder layer causes heating of the raw material powder particles and, as a result, melting or sintering. Subsequently, additional raw material powder layers are continuously applied to the layer on the carrier that has already been irradiated until the work piece reaches the desired shape and size. Specifically, selective electron beam melting, selective laser melting, or laser sintering can be used for the manufacture of prototypes, tools, replacement parts, or medical prostheses, such as dental or orthopedic prostheses, based on CAD data.

[0004] Throughout this disclosure, all references to selective laser melting are equally applicable to selective laser sintering, selective electron beam melting, stereolithography, MELATO, selective thermal sintering, or any other energy beam-based additive manufacturing method. Thus, any reference to additive manufacturing can be applicable to one or more of selective laser melting, selective laser sintering, selective electron beam melting, stereolithography, MELATO, selective thermal sintering, and any other energy beam-based additive manufacturing method.

[0005] An important parameter of the additive manufacturing method is the quality of the manufactured workpiece. Moreover, manufacturing efficiency is extremely important in the sense of, for example, keeping the manufacturing cycle as short as possible. For example, many strategies are known to increase the manufacturing speed of a single workpiece layer. However, when manufacturing large workpieces, the known solutions do not necessarily achieve the desired efficiency and / or quality. SUMMARY OF THE INVENTION

[0006] Accordingly, in particular, it is an object of the present invention to improve the quality of a three-dimensional workpiece manufactured using an additive manufacturing process. Further, in particular, it is an object of the present invention to improve the efficiency in preparing a three-dimensional workpiece using an additive manufacturing process while avoiding spoiling the quality of the manufactured three-dimensional workpiece.

[0007] Accordingly, in a method of controlling an irradiation beam for irradiating a raw material powder layer in an additive manufacturing process for manufacturing a three-dimensional workpiece, a step of depositing the layer of raw material powder on a carrier and / or on a preceding material layer on the carrier using a layer depositing mechanism, and a step of controlling the irradiation beam to irradiate at least a part of the raw material powder layer within an irradiation region when a distance between the irradiation region and the layer depositing mechanism is greater than a threshold distance, where the threshold distance is (i) a moving speed of the layer depositing mechanism, and (ii) a speed v of a gas flow on the raw material powder layer gA method is described that is influenced by steps.

[0008] The inventors recognized that the laminar gas flow across the entire layer of the powder bed can be disturbed, in particular due to the movement of the layer deposition mechanism. Since it may be desirable to irradiate the raw material powder layer already while the layer deposition mechanism is moving, it may be necessary to define the irradiation area in such a way that the distance between the part of the raw material powder layer where the laminar gas flow is disturbed above and the irradiation area can be maintained in particular during the movement of the layer deposition mechanism. The gas flow in the irradiation area can thus no longer be stirred by the turbulent flow that may have occurred due to the movement of the layer deposition mechanism. As a result, the irradiation of the raw material powder layer can be started while the layer deposition mechanism is still moving, so that the quality of the workpiece to be manufactured is improved while efficiently preparing the three-dimensional workpiece.

[0009] The moving speed of the layer deposition mechanism (and, in some examples, the shape of the layer deposition mechanism, as will be further outlined below) can affect any turbulent flow that may occur during the movement of the layer deposition mechanism, but when controlling the irradiation beam, the speed of the gas flow across the entire raw material powder layer is also taken into account. This is particularly applicable in the case of an exemplary implementation of the present disclosure, since any turbulent flow can be carried away in the forward direction and away from the raw material powder layer to be irradiated due to the gas flow. The speed of the gas flow itself causes turbulent flow for gas flow speeds greater than a threshold speed depending on the shape and / or moving speed of the layer deposition mechanism, but the faster the gas flow speed, the faster any turbulent flow can be kept away. Therefore, it may be necessary to find a balance between these considerations and optimize the speed of the gas flow in view of any operating conditions and parameters for manufacturing the three-dimensional workpiece.

[0010] As will be appreciated, the layer deposition mechanism can encounter acceleration and deceleration during movement. Thus, throughout this disclosure, any reference to the movement speed of the layer deposition mechanism refers to the average movement speed of the layer deposition mechanism over the entire travel distance (specifically, since the layer deposition mechanism can move over one or more portions where no raw material powder (layer) is deposited, over the entire powder bed, i.e., the entire raw material powder layer), the average movement speed of the layer deposition mechanism over the total travel distance of the layer deposition mechanism (where the total travel distance can relate to one or more strokes of the layer deposition mechanism), and can relate to one or more of the movement speeds of the layer deposition mechanism at a specific location (specifically, over the entire powder bed, i.e., the entire raw material powder layer).

[0011] In some embodiments, while the layer deposition mechanism moves across the carrier and / or the precursor material layer on the carrier, the distance is kept greater than a threshold distance. This can ensure an improvement in the manufacturing efficiency of the three-dimensional workpiece while enabling a high quality of the manufactured workpiece.

[0012] The gas flow flows in a first direction parallel to the plane defined by the carrier, and the layer deposition mechanism is configured to move in a second direction orthogonal or substantially orthogonal to the first direction, the second direction being parallel to the plane defined by the carrier, and the threshold distance being proportional to v ldm / v g where v ldm is the movement speed of the layer deposition mechanism in the second direction. Since the raw material powder layer cannot be irradiated within a region where turbulent flow can occur above, this can ensure a high quality of the manufactured workpiece. In some embodiments, the threshold distance in the second direction is p·v ldm / v g+o, where p is a coefficient greater than 0 and o is an offset greater than 0. The offset may be, in some embodiments, from 10 mm to 50 mm (e.g., 10 mm, 15 mm, 20 mm,..., 50 mm). The offset may be variable in some embodiments, for example, between 10 mm and 50 mm, and more particularly may vary stepwise (e.g., in steps of 1 mm or 0.1 mm) and / or continuously. The offset may ensure that the irradiation area is further away from an area where some turbulent flow may occur. The offset may be selected, for example, according to one or more machine / device parameters such as the possible deflection speed (e.g., the rotation speed of one or more scanner optical device mirrors) of the (one or more) scanner optical device mirrors, and / or the system latency for the control signal and / or the shape of the layer deposition mechanism. In some embodiments, p may represent a distance value in a first direction. In this case, the threshold distance may be lower on the gas inlet side of the raw material powder layer than on the gas outlet side of the raw material powder layer. The starting point (p = 0) of the distance value may preferably be at the gas inlet, the edge of the raw material powder layer, or any point therebetween.

[0013] In some embodiments, the velocity of the gas flow can be measured at one or more heights above the raw material powder layer. In some embodiments, the one or more heights may be from 5 mm to 50 mm above the raw material powder layer, such that the velocity of the gas flow can be measured at one or more heights between 5 mm and 50 mm. The gas flow can, here, in some embodiments, be measured stepwise at two or more heights, for example, in steps of 1 mm or 0.1 mm, and / or continuously, more particularly between 5 mm and 50 mm. Additionally or alternatively, the velocity of the gas flow may be measured at the height of the gas inlet.

[0014] In some embodiments, the velocity of the gas flow can be measured at one or more points / places within the build chamber, specifically at the gas inlet and / or the gas outlet, and / or at the gas inlet side edge / edge region of the powder bed (i.e., the raw material powder layer), and / or at the gas outlet side edge / edge region of the powder bed, and / or above the powder bed. Throughout the present disclosure, any reference to "gas flow velocity" can mean a measurement at one of these points / places, or an average value of one or more (specifically any combination) of the measurements at two or more of these points / places.

[0015] In some embodiments, the irradiation area excludes the area on the raw material powder layer that is closer to the layer deposition mechanism than the threshold distance when the layer deposition mechanism moves parallel to the carrier and / or the preceding material layer. Thus, irradiation of the raw material powder layer can be avoided in areas where any turbulence resulting from the movement of the layer deposition mechanism may still exist.

[0016] In some embodiments, the threshold distance is further influenced by the shape of the layer deposition mechanism. As will be recognized, the shape of the layer deposition mechanism may cause some turbulence, specifically when the layer deposition mechanism does not have an aerodynamic shape (or even when it has an aerodynamic shape). It is recognized that the higher the movement speed of the layer deposition mechanism, the more prominent any turbulence can become. Furthermore, as outlined above, the velocity of the gas flow itself can cause turbulence for gas flow velocities greater than the threshold velocity depending on the shape and / or movement speed of the layer deposition mechanism, but the higher the velocity of the gas flow, the more quickly any turbulence can be carried away. Therefore, the above parameters can be taken into account when controlling the irradiation beam, specifically when the layer deposition mechanism moves across the carrier and / or the preceding material layer on the carrier.

[0017] In some embodiments, the threshold distance also depends on the gas flow direction of the gas flow. The gas flow direction can affect where and to what extent any turbulence can occur. Taking the gas flow direction into account can therefore make it possible to prepare a three-dimensional workpiece with even higher quality, while still ensuring that the three-dimensional workpiece can be produced while the layer deposition mechanism is still moving.

[0018] In some embodiments, the gas flow velocity v above the raw powder layer g is the velocity of gas flow in a volume within a threshold height from the layer deposition mechanism when the layer deposition mechanism moves parallel to the carrier and / or the preceding material layer, v g As will be appreciated, this parameter may make it possible to determine to what extent any potential turbulence may still be present within a threshold distance to the layer deposition mechanism, thus making it possible to start irradiating the feedstock powder layer early on while the layer deposition mechanism is moving.

[0019] In some embodiments, the excluded area is 1 / v g In other words, the higher the velocity of the gas flow (e.g., at one or more predefined heights above the feed powder layer), the smaller the area that is excluded, since for a higher velocity of the gas flow, any turbulence can be pushed away by the gas flow faster.

[0020] In some embodiments, the moving speed of the layer deposition mechanism is adjustable from 0 m / s to 0.5 m / s, particularly continuously and / or in increments of 0.01 m / s. For example, a speed of 0.2 m / s may allow efficient preparation of the feedstock powder layer by the layer deposition mechanism as it moves, while any turbulence caused by the movement of the layer deposition mechanism may be kept to a reasonable level or to a reasonable minimum.

[0021] In some embodiments, the layer deposition mechanism has a rectangular or substantially rectangular shape when viewed from a perspective of a cross-section orthogonal to the plane in which the carrier and / or the preceding material layer on the carrier extends, and the irradiation region excludes a region on the side of the layer deposition mechanism that is opposite to the moving direction of the layer deposition mechanism in the plane. This embodiment makes it possible to take into account any potential turbulence that may be formed, in particular or mainly, behind the layer deposition mechanism, i.e., on the side of the layer deposition mechanism facing outward when viewed from the moving direction of the layer deposition mechanism.

[0022] In some embodiments, the region has a triangular or substantially triangular shape, and the adjacent sides of the triangle are formed by the side of the layer deposition mechanism that is opposite to the moving direction of the layer deposition mechanism in the plane. The inventors have found that any potential turbulence can occur in such a triangular or substantially triangular region, and thus, when controlling the irradiation beam, in particular when determining which single or multiple portions of the raw material powder layer within a threshold distance from the layer deposition mechanism should be excluded from irradiation (for at least a predefined time), it is possible to take this phenomenon into account. In some embodiments, one side of the irradiation region is defined by the hypotenuse of the triangle, and the triangle is disposed between the layer deposition mechanism and the irradiation region.

[0023] In some embodiments, v g is from 1.0 m / s to 2.0 m / s, in particular 1.5 m / s, and more particularly v g is adjustable. This has been proven to be the velocity of the gas flow that does not cause itself an excessive amount of turbulence when passing through the (moving) layer deposition mechanism, while on the other hand the gas flow can efficiently remove any turbulence caused by the movement of the layer deposition mechanism.

[0024] In some embodiments, the irradiation of the raw material powder layer is controlled to start within the region where the layer deposition mechanism starts to form the raw material powder layer. It is in this region that any potential turbulence may already be (or initially be) diverted by the gas flow.

[0025] In some embodiments, the irradiation of the raw material powder layer is controlled to start at or generally opposite to the gas inlet for the gas flow. This enables the raw material powder layer to be irradiated in a direction opposite to the gas flow direction, so that any smoke created due to the irradiation of the raw material powder layer does not affect the subsequent irradiation of the raw material powder layer within the unfrozen region of the layer. In some embodiments, the irradiation is controlled to continue against the direction of the gas flow.

[0026] In some embodiments, the irradiation beam and / or the second irradiation beam are controlled to irradiate an area towards which the layer deposition mechanism moves when the carrier and / or the precursor material layer on the carrier extends therein. It can be assumed that no (or relatively little) turbulence occurs in this area. In some embodiments, the area towards which the layer deposition mechanism moves in the plane is changed during irradiation so as to come to a predefined safe distance from the layer deposition mechanism, which may make it possible to ensure that no (or relatively little) turbulence occurs within this irradiated area.

[0027] Furthermore, a computer program product including a program code portion for performing the method of any of the exemplary implementations described herein when executed on one or more computing devices is described. The computer program product may be stored on a computer-readable recording medium in some embodiments.

[0028] Furthermore, in a device for controlling an irradiation beam for irradiating a raw material powder layer in a layer manufacturing process for manufacturing a three-dimensional workpiece, one or more processors and a memory operatively coupled to the one or more processors, the memory storing a program code portion that, when executed by the one or more processors, causes the device to control the irradiation beam to irradiate at least a portion of the raw material powder layer within an irradiation area when a distance between a layer deposition mechanism used to deposit the raw material powder layer on a carrier and / or on a preceding material layer on the carrier and the irradiation area is greater than a threshold distance, the threshold distance being determined by (i) a moving speed of the layer deposition mechanism and (ii) a speed v of a gas flow on the raw material powder layer g will be described for a device including a memory. The device may be configured to perform a method according to any of the exemplary implementations generally described throughout the present disclosure.

[0029] Furthermore, in an apparatus for manufacturing a three-dimensional workpiece via a layer manufacturing method, a carrier configured to accommodate a material for manufacturing the three-dimensional workpiece, a material supply unit configured to supply the material to the carrier and / or one or more preceding material layers on the carrier, a layer deposition mechanism for forming the supplied material into a material layer on the carrier and / or one or more preceding material layers on the carrier, a solidification device configured to solidify the material supplied to the carrier and / or one or more preceding material layers on the carrier for manufacturing the three-dimensional workpiece, a gas supply unit configured to supply a shielding gas to an area of the material layer to be solidified by the solidification device, a process chamber including the gas supply unit and the solidification device, and a device according to any of the exemplary embodiments generally described throughout the present disclosure will be described for an apparatus including the same. In some examples, the apparatus includes a computer program product according to any of the exemplary embodiments generally described throughout the present disclosure.

[0030] These and other aspects of the invention will now be described, by way of example only, with further reference to the accompanying drawings, in which like reference numerals denote like parts.

Brief Description of the Drawings

[0031]

Figure 1

Figure 2a

Figure 2b

Figure 3

Figure 4

Figure 5

DETAILED DESCRIPTION OF THE INVENTION

[0032] The inventors have recognized that when the layer deposition mechanism is moved, the laminar gas flow on the powder bed can be disturbed.

[0033] If the irradiation of the raw material powder layer has to be started while the layer deposition mechanism is still moving, it may be necessary to maintain a sufficiently large distance to the layer deposition mechanism in order to start the irradiation within an already calmed gas flow region. When the gas flow within the area of the build platform has reached the desired state again, the irradiation can be started during the coating process.

[0034] Since the turbulent flow is carried by the gas flow, the turbulent flow region is formed within the ideal triangle behind the layer deposition mechanism in some embodiments. As will be appreciated, the shape of the turbulent flow region is based, among other things, on the shape of the layer deposition mechanism which can take on all kinds of shapes in some embodiments.

[0035] In this embodiment, the extension of the triangle behind the layer deposition mechanism can be affected by the moving speed of the layer deposition mechanism (approximately 0.2 m / s in some embodiments), the shape of the layer deposition mechanism in some embodiments (due to the generation of turbulent flow), and the speed of the gas flow (in some embodiments, for example, approximately 1.5 m / s at a height of 30 mm above the powder bed). In some embodiments, the typical width of the powder bed is 150 mm to 1000 mm.

[0036] The distance from the layer deposition mechanism at which the turbulent flow should no longer occur (the "calming distance") can be set either as the distance parallel to the layer deposition mechanism calculated by the longest extension of the triangle (at the offside edge of the gas flow) in some embodiments, or as an arbitrary offset (additional safety distance) in some embodiments. Alternatively, a boundary parallel to the hypotenuse (along it or in addition to an offset) is possible, i.e., the irradiation can start earlier upstream than downstream of the gas flow in some embodiments.

[0037] Irradiation can preferably be started at the edge of the powder bed where the layer deposition mechanism has started to move across the powder bed, and more preferably on the opposite side of the gas inlet, so that the irradiation process can be carried out against the gas flow. At the offside edge, irradiation can be started immediately when the layer deposition mechanism has covered at least the calming distance.

[0038] Furthermore, the irradiation "in front" of the layer deposition mechanism can be carried out simultaneously (using the same irradiation source and / or a second irradiation source). In some embodiments, it is only necessary to maintain a small safety distance from the layer deposition mechanism, so that a gentle (laminar) gas flow can be assumed within this area in front of the layer deposition mechanism.

[0039] Specifically, the present invention relates to a method, device and apparatus for manufacturing a three-dimensional workpiece using a stereolithography process, as well as a layer deposition mechanism used therein.

[0040] The embodiments described herein enable an increase in manufacturability in a stereolithography process, specifically in a selective laser melting machine. Embodiments according to the present disclosure enable the irradiation to be started already during the coating (with a powder material), or at least after the layer deposition mechanism has left the area of the build platform, the gas flow within an area of the build platform has already reached the desired state again, and thus the irradiation of the next layer can be started immediately without any loss of quality.

[0041] In some embodiments, the layer deposition mechanism and the (mechanical) layer deposition mechanism suspension or fixture of the layer deposition mechanism are designed in such a way that they are affected as little as possible by the gas flow guided across the entire build platform. In some embodiments, the suspension of the layer deposition mechanism is designed as a lattice structure, specifically a honeycomb structure or a lamella structure, or as individual narrow webs with a relatively small cross-sectional area in a cross-sectional plane perpendicular to the gas flow direction compared to the area in the cross-sectional plane bounded by the outer periphery of the layer deposition mechanism suspension or the layer deposition mechanism. The layer deposition mechanism itself is, in some embodiments, aerodynamically shaped and, in some embodiments, can have gently tapered side surfaces so as to minimize the turbulence as the gas flow passes over it.

[0042] FIG. 1 shows a schematic cross-sectional view of an apparatus 100 for manufacturing a three-dimensional workpiece 102 using a stereolithography process.

[0043] In this embodiment, the apparatus 100 includes an irradiation unit 104 (e.g., a laser or particle beam generator) coupled to a deflection unit (scanner) 106 such that the irradiation beam 108 can be directed onto the powder layer 110 or powder bed. By controlling the irradiation beam 108 in such a manner, the workpiece 102 can be appropriately manufactured with the powder material 111 not solidified in some regions by the irradiation beam 108.

[0044] In this embodiment, the apparatus includes a carrier 112 on which the three-dimensional workpiece 102 is manufactured. The carrier 112 can be vertically moved by a lifting mechanism 114 within the process chamber 116 as in this embodiment.

[0045] In this embodiment, the apparatus 100 includes a layer deposition mechanism 118 substantially in the shape of a pyramid or trapezoid. In all embodiments of the present disclosure, the layer deposition mechanism can similarly have only one inclined side surface (e.g., the side surface facing the gas inlet or outlet), and the other side surface is orthogonal to the carrier plane.

[0046] In this embodiment, the layer deposition mechanism 118 of the apparatus 100 has a lower side 119a and an opposite side 119b parallel thereto, and the side 119a to which the powder material is applied to the carrier and / or powder bed has a larger area than the side 119b. A powder spreading device 118b (i.e., a spreading element or scraper element, such as a coater lip, brush, roller or pusher) is attached to the lower side of the layer deposition mechanism 118.

[0047] In this embodiment, the layer deposition mechanism 118 has gently tapered side surfaces 119c and 119d. Specifically, the transitions between the side surface 119c and the side 119c and between the side 119b and the side surface 119d are convex in shape, thus enabling the gas flow to be guided across the entire layer deposition mechanism 118 without causing (or causing only a slight amount of) turbulence in the gas flow.

[0048] In this embodiment, the layer deposition mechanism 118 is coupled to the layer deposition mechanism suspensions 120a and 120b in two regions. In some embodiments, the layer deposition mechanism is coupled to the layer deposition mechanism suspension in a single region. In this embodiment, the apparatus 100 further includes guide rails and / or drive mechanisms 122a and 122b by which the layer deposition mechanism 118, together with the layer deposition mechanism suspensions 120a and 120b, is movable across the entire carrier 112 or, in this example, across the entire powder layer 110.

[0049] The apparatus 100 further includes, in this embodiment, a gas inlet 124 and a gas outlet 126 such that a gas flow 125 can be generated within the apparatus 100, and the apparatus forms a gas flow, specifically a laminar gas flow, above the carrier 112 or above the uppermost powder layer 110 if the layer deposition mechanism 118 or the carrier 112 is not positioned above it. The axis 128 between the gas inlet 124 and the gas outlet 126 is indicated by a dashed line. In this embodiment, the apparatus further includes a gas inlet 130 for generating a second gas flow 132 between the gas inlet 130 and the gas outlet 126.

[0050] The surface 119c of the layer deposition mechanism 118 facing the gas inlet nozzle (i.e., the gas inlet 124) acts as a gas conducting surface and is thus preferably formed at an angle of 0° to 90° with respect to the axis 128, approximately 45° in this example.

[0051] The layer deposition mechanism suspension 120a on the side 119c and / or the other side 119d of the surface is formed at least partially as a gas flowable structure, specifically as a lattice structure and / or a lamella structure.

[0052] In this embodiment, the gas flowable structures of the layer deposition mechanism suspensions 120a, 120b have at least partially a flow guiding cross-section, specifically an elliptical or teardrop-shaped cross-section.

[0053] In this embodiment, the surface 119d of the layer deposition mechanism 118 on the side opposite to the gas outflow opening, i.e., the gas outlet 126, also functions as a gas guiding surface and preferably forms an angle of 0° to 90° with respect to the axis 128, which is about 45° in this embodiment. Specifically, the angle may be the same as the angle of the surface 119c with respect to the axis 128. Alternatively, the layer deposition mechanism 118 may also be continuous in the direction of the outflow opening, specifically up to the wall that houses the outflow opening, i.e., the gas outlet 126, and can at least partially cover the gas outlet 126.

[0054] In this embodiment, the transition from the side 119c and / or the side 119d to the upper surface / side 119b of the layer deposition mechanism 118 is convex in shape, enabling the gas flow to contact the surface and avoid turbulent flow.

[0055] In some embodiments, the front and / or rear sides of the layer deposition mechanism 118 are also angled similarly. Alternatively, the front and / or rear portions of the layer deposition mechanism 118 may be configured to be angled during movement across the powder layer 110 and can move to an upright position so as to just abut against the wall of the process chamber at one or both of the stationary positions (on the opposite sides of the powder layer). This mechanism is coupled to the opening of the powder chute in some embodiments.

[0056] The flow guiding sections of the layer deposition mechanism suspensions 120a, 120b can be designed such that the gas flow is deflected in different shapes according to the moving direction, and these sections can be designed to be adjustable for this purpose in detail. According to the moving direction, these sections can be aligned in the direction of the resulting relative flow direction so that the influence on the gas flow is minimized as much as possible at this time.

[0057] FIG. 2a shows a schematic exemplary cross-sectional side view 200 of the layer deposition mechanism 118 used during the additive manufacturing process according to some exemplary implementations described herein.

[0058] As can be seen, while the layer deposition mechanism 118 moves in the moving direction 204, on one hand, between the irradiation beam 108 and the irradiation region 203 that solidifies the raw material powder, and on the other hand, between the layer deposition mechanism 118, a distance 202 (referred to as the "calming distance" as outlined generally above) can be maintained. Thus, it can be ensured that the irradiation beam 108 does not irradiate the raw material powder too close to the layer deposition mechanism 118 where turbulent flow can occur. The distance 202 is determined in this embodiment based on the shape of the layer deposition mechanism 118, the moving speed of the layer deposition mechanism 118, and the speed of the gas flow across the entire layer of the raw material powder.

[0059] FIG. 2b shows a top view 210 of a schematic illustration of a layer deposition mechanism 118 used during a stereolithography process according to some exemplary implementations described herein.

[0060] The gas flow 212 above the raw material powder layer and the layer deposition mechanism 118 is indicated by the arrows.

[0061] As can be seen, in this embodiment, a (virtual) triangle 214 is formed between the irradiation region 203 and the layer deposition mechanism 118, whereby turbulent flow can occur within the region of the triangle 214, and thus this region must be excluded from irradiation by the irradiation beam 108. This region changes as the layer deposition mechanism 118 moves.

[0062] In this embodiment, an offset (the dashed line in FIG. 2b) is provided between the triangular region 214 and the irradiation region 203, so that an additional safety distance can be provided between the layer deposition mechanism 118 and the irradiation region 203 to ensure that no turbulent flow (only turbulent flow below the threshold value) occurs within the irradiation region 203. In an embodiment where the distance 202 is defined parallel to the layer deposition mechanism 118, the offset can be defined as an offset 216 that exists parallel to the edge of the layer deposition mechanism 118 on the side opposite to the moving direction of the layer deposition mechanism 118. In an embodiment where the edge of the irradiation region 203 is defined by the hypotenuse of the triangle 214, the offset can be defined as an offset 218 that is aligned parallel to the hypotenuse of the triangle 214. The offset 216 and / or the offset 218 are 10 mm to 50 mm in this embodiment. The offset 216 and / or the offset 218 can be variable (stepwise, for example, in steps of 1 mm or 0.1 mm, and / or continuously as generally described above).

[0063] In this embodiment, the irradiation starts at the edge of the powder bed where the layer deposition mechanism starts its movement (and preferably additionally starts on the side opposite to the gas inlet, thus enabling irradiation against the gas flow). In this embodiment, the irradiation is immediately started when the layer deposition mechanism covers at least the distance 202 at the offside edge.

[0064] FIG. 3 shows a flowchart of a method 300 according to some exemplary implementations described herein.

[0065] In this embodiment, the method 300 includes, at step S302, depositing the layer of raw material powder on the carrier and / or on the preceding material layer on the carrier using the layer deposition mechanism. At step S304, the method 300 includes controlling the irradiation beam to irradiate at least a portion of the raw material powder layer within the irradiation region when the distance between the irradiation region and the layer deposition mechanism is greater than a threshold distance, where the threshold distance is (i) the moving speed of the layer deposition mechanism, and (ii) the speed v of the gas flow on the raw material powder layerg is influenced by

[0066] FIG. 4 shows a block diagram of a device 400 for controlling an irradiation beam to irradiate a raw material powder layer in a layer manufacturing process for manufacturing a three-dimensional workpiece, according to some exemplary implementations described herein.

[0067] In this embodiment, the device 400 includes one or more processors 402 and a memory 404 operatively coupled to the one or more processors, the memory being configured to store a program code portion that, when executed by the one or more processors, causes the device to control the irradiation beam to irradiate at least a portion of the raw material powder layer within an irradiation area when a distance between a layer deposition mechanism and the irradiation area used to deposit the raw material powder layer on a carrier and / or on a preceding material layer on the carrier is greater than a threshold distance, the threshold distance being determined by (i) a moving speed of the layer deposition mechanism and (ii) a speed v of a gas flow on the raw material powder layer g is influenced by, and includes the memory.

[0068] FIG. 5 shows a block diagram of an apparatus 500 for manufacturing a three-dimensional workpiece via a layer manufacturing method according to some exemplary implementations described herein.

[0069] In this embodiment, the apparatus 500 includes a carrier 112 configured to contain a material for manufacturing a three-dimensional workpiece, a material supply unit 502 configured to supply the material to the carrier and / or one or more precursor material layers on the carrier, a layer deposition mechanism 118 for forming the supplied material into a material layer on the carrier and / or one or more precursor material layers on the carrier, a solidification device 104 configured to solidify the material supplied to the carrier and / or one or more precursor material layers on the carrier for manufacturing the three-dimensional workpiece, a gas supply unit 504 configured to supply a shielding gas to a region of the material layer to be solidified by the solidification device, a process chamber 506 including the gas supply unit and the solidification device, and a device 400 according to the embodiments (specifically, FIG. 4) schematically described herein. The carrier 112, the material supply unit 502, and the layer deposition mechanism 118 may similarly be disposed within the process chamber 506.

[0070] It will doubtless be apparent to those skilled in the art that many other alternatives will occur to them. It is understood that the present invention is not limited to the described embodiments and exemplary implementations, but includes modifications that are apparent to those skilled in the art and fall within the scope of the claims appended hereto. The above embodiments may be described as follows but are not limited to the following. [Configuration 1] In a method of controlling an irradiation beam for irradiating a raw material powder layer in a layer manufacturing process for manufacturing a three-dimensional workpiece, depositing the raw material powder layer on a carrier and / or on a preceding material layer on the carrier using a layer deposition mechanism; controlling the irradiation beam to irradiate at least a portion of the raw material powder layer within an irradiation area when a distance between the irradiation area and the layer deposition mechanism is greater than a threshold distance, where the threshold distance is (i) the moving speed of the layer deposition mechanism, and (ii) the speed v of a gas flow on the raw material powder layer g 、 and is affected by these factors, the step; A method comprising the steps. [Configuration 2] The method according to Configuration 1, wherein the distance is kept greater than the threshold distance while the layer deposition mechanism moves across the carrier and / or the preceding material layer on the carrier. [Configuration 3] The gas flow flows in a first direction parallel to a plane defined by the carrier, and the layer deposition mechanism is configured to move in a second direction orthogonal or substantially orthogonal to the first direction, the second direction being parallel to the plane defined by the carrier, and the threshold distance being proportional to v ldm / v gin the second direction, where v ldm is the moving speed of the layer deposition mechanism in the second direction, the method according to Configuration 1 or 2. [Configuration 4] The threshold distance in the second direction is p·v ldm / v g +o, where p is a coefficient greater than 0 and o is an offset greater than 0, the method according to Configuration 3. [Configuration 5] The method according to any one of Configurations 1 to 4, wherein the irradiation area excludes an area on the raw material powder layer that is closer to the layer deposition mechanism than the threshold distance when the layer deposition mechanism moves parallel to the carrier and / or the preceding material layer. [Configuration 6] The method according to any one of Configurations 1 to 5, wherein the threshold distance is further affected by the shape of the layer deposition mechanism. [Configuration 7] The method according to any one of Configurations 1 to 6, wherein the threshold distance is further affected by the gas flow direction of the gas flow. [Configuration 8] The speed v of the gas flow on the raw material powder layer g includes the speed v of the gas flow in a volume within a threshold height from the layer deposition mechanism when the layer deposition mechanism moves parallel to the carrier and / or the preceding material layer. g The method according to any one of Configurations 1 to 7. [Configuration 9] The excluded area is proportional to 1 / v g The method according to any one of items 1 to 8 of Configuration 1, when it belongs to Configuration 5 and is proportional to [Configuration 10] The method according to any one of items 1 to 9 of Configuration 1, wherein the moving speed of the layer deposition mechanism is from 0 m / s to 0.5 m / s, and in particular, it can be adjusted continuously and / or in increments of 0.01 m / s. [Configuration 11] The layer deposition mechanism has a rectangular or substantially rectangular shape when viewed from a perspective of a cross-section perpendicular to the plane in which the carrier and / or the preceding material layer on the carrier extends, and the irradiation area excludes the area on the side of the layer deposition mechanism that is opposite to the moving direction of the layer deposition mechanism in the plane. The method according to any one of items 1 to 10 of Configuration 1. [Configuration 12] The area has a triangular or substantially triangular shape, and the adjacent sides of the triangle are formed by the side of the layer deposition mechanism that is opposite to the moving direction of the layer deposition mechanism in the plane. The method according to Configuration 11. [Configuration 13] One side of the irradiation area is defined by the hypotenuse of a triangle, and the triangle is disposed between the layer deposition mechanism and the irradiation area. The method according to Configuration 12. [Configuration 14] v g is from 1.0 m / s to 2.0 m / s, in particular 1.5 m / s, and more particularly v g is adjustable. The method according to any one of items 1 to 13 of Configuration 1. [Configuration 15] The irradiation of the raw material powder layer is controlled to start within the area where the layer deposition mechanism starts to form the raw material powder layer. The method according to any one of items 1 to 14 of Configuration 1. [Configuration 16] The irradiation of the raw material powder layer is controlled to start at a location opposite to or generally opposite to the gas inlet for the gas flow. The method according to any one of items 1 to 15 of Configuration 1. [Configuration 17] The irradiation is controlled to continue against the direction of the gas flow. The method according to Configuration 16. [Configuration 18] The irradiation beam and / or the second irradiation beam are controlled to irradiate the area that the layer deposition mechanism is moving towards when it moves in the plane in which the carrier and / or the preceding material layer on the carrier extends. The method according to any one of items 1 to 17 of Configuration 1. [Configuration 19] The area that the layer deposition mechanism is moving towards when it moves in the plane is changed during irradiation so that it reaches a predefined safe distance from the layer deposition mechanism. The method according to Configuration 18. [Configuration 20] A computer program product including a program code portion for performing the method according to any one of configurations 1 to 19 when executed on one or more computing devices. [Configuration 21] The computer program product according to configuration 20, stored on a computer-readable recording medium. [Configuration 22] In a device for controlling an irradiation beam for irradiating a raw material powder layer in a layer manufacturing process for manufacturing a three-dimensional workpiece, One or more processors; A memory operatively coupled to the one or more processors, the memory being configured to store a program code portion that, when executed by the one or more processors, causes the device to control the irradiation beam to irradiate at least a portion of the raw material powder layer within the irradiation area when a distance between a layer deposition mechanism used to deposit the raw material powder layer on a carrier and / or on a preceding material layer on the carrier is greater than a threshold distance, the threshold distance being determined by (i) a moving speed of the layer deposition mechanism and (ii) a speed v of a gas flow on the raw material powder layer g A memory, influenced by; A device including. [Configuration 23] Configured to perform the method according to any one of configurations 1 to 19; The device according to configuration 22. [Configuration 24] In an apparatus for manufacturing a three-dimensional workpiece via a layer manufacturing method, A carrier configured to accommodate a material for manufacturing the three-dimensional workpiece; A material supply unit configured to supply material to the carrier and / or one or more preceding material layers on the carrier; A layer deposition mechanism for forming the supplied material into a material layer on the carrier and / or one or more preceding material layers on the carrier; A solidification device configured to solidify the material supplied to the carrier and / or the one or more preceding material layers on the carrier for manufacturing the three-dimensional workpiece; A gas supply unit configured to supply a shielding gas to an area of the material layer to be solidified by the solidification device; A process chamber including the gas supply unit and the solidification device; The device according to configuration 22 or 23; An apparatus including. [Configuration 25] The apparatus according to configuration 24, further including the computer program product according to configuration 20 or 21.

Claims

1. In a method of controlling an irradiation beam for irradiating a raw material powder layer in a layer manufacturing process for manufacturing a three-dimensional workpiece, depositing the raw material powder layer on a carrier and / or on a preceding material layer on the carrier using a layer deposition mechanism; controlling the irradiation beam to irradiate at least a portion of the raw material powder layer within an irradiation area when a distance between the irradiation area and the layer deposition mechanism is greater than a threshold distance, wherein the threshold distance is (i) the moving speed of the layer deposition mechanism, and (ii) the speed vg of a gas flow on the raw material powder layer, and is influenced by these factors, comprising: the gas flow flows in a first direction parallel to a plane defined by the carrier, and the layer deposition mechanism is configured to move in a second direction orthogonal to the first direction, and the second direction is parallel to the plane defined by the carrier, a method.

2. The method according to claim 1, wherein the distance is kept greater than the threshold distance while the layer deposition mechanism moves across the carrier and / or the preceding material layer on the carrier.

3. The method according to claim 1, wherein the threshold distance is proportional to vldm / vg in the second direction, where vldm is the moving speed of the layer deposition mechanism in the second direction.

4. The threshold distance is adjusted by an equation expressed as p·vldm / vg + o in the second direction, where p is a coefficient greater than 0 and o is an offset greater than 0, according to the method of claim 1.

5. The method according to claim 1, wherein the irradiation area excludes an area on the raw material powder layer that is closer to the layer deposition mechanism than the threshold distance when the layer deposition mechanism moves parallel to the carrier and / or the preceding material layer.

6. The method according to claim 1, wherein the threshold distance is further influenced by the shape of the layer deposition mechanism.

7. The method according to claim 1, wherein the threshold distance is further influenced by the gas flow direction of the gas flow.

8. The method according to claim 1, wherein the speed vg of the gas flow on the raw material powder layer includes the speed vg of the gas flow in a volume within a threshold height from the layer deposition mechanism when the layer deposition mechanism moves parallel to the carrier and / or the preceding material layer.

9. When the layer deposition mechanism moves parallel to the carrier and / or the preceding material layer, the irradiation area excludes the area on the raw material powder layer that is closer to the layer deposition mechanism than the threshold distance, and the excluded area is directly proportional to 1 / vg. The method according to claim 1.

10. The moving speed of the layer deposition mechanism can be adjusted continuously and / or based on an increment of 0.01 m / s from 0 m / s to 0.5 m / s. The method according to claim 1.

11. The layer deposition mechanism has a rectangular shape when viewed from a perspective of a cross-section orthogonal to the plane in which the carrier and / or the preceding material layer on the carrier extends, and the irradiation area excludes the area on the side of the layer deposition mechanism that is opposite to the moving direction of the layer deposition mechanism within the plane. The method according to claim 1.

12. The area has a triangular shape, the hypotenuse of the triangle is formed by the edge of the irradiation area, and one of the sides other than the hypotenuse is formed by the side of the layer deposition mechanism that is opposite to the moving direction of the layer deposition mechanism within the plane. The method according to claim 11.

13. One side of the irradiation area is defined by the hypotenuse of the triangle, and the triangle is disposed between the layer deposition mechanism and the irradiation area. The method according to claim 12.

14. The speed vg can be adjusted in the range of 1.0 m / s to 2.0 m / s. The method according to claim 1.

15. The irradiation of the raw material powder layer is controlled to start within the area where the layer deposition mechanism starts to form the raw material powder layer. The method according to claim 1.

16. The irradiation of the raw material powder layer is controlled to start at a location opposite to the gas inlet for the gas flow. The method according to claim 1.

17. The irradiation is controlled in a direction opposite to the gas flow. The method according to claim 16.

18. The irradiation beam and / or the second irradiation beam are controlled to irradiate the area that the layer deposition mechanism is moving towards when moving within the plane in which the carrier and / or the preceding material layer on the carrier extends. The method according to claim 1.

19. The method according to claim 18, wherein when the layer deposition mechanism moves towards the area in the plane, the area is changed during irradiation so as to be at a predefined safety distance from the layer deposition mechanism.

20. A computer program product comprising a program code portion for performing the method according to claim 1 when executed on one or more computing devices.

21. The computer program product according to claim 20, stored on a computer-readable recording medium.

22. In a device for controlling an irradiation beam for irradiating a raw material powder layer in a stereolithography process for manufacturing a three-dimensional workpiece, one or more processors; a memory operatively coupled to the one or more processors, the memory being configured to store, when executed by the one or more processors, a program code portion for controlling the irradiation beam to irradiate at least a portion of the raw material powder layer within the irradiation area when a distance between a layer deposition mechanism and an irradiation area used for depositing the raw material powder layer on a carrier and / or on a preceding material layer on the carrier is greater than a threshold distance, the threshold distance being determined by (i) a moving speed of the layer deposition mechanism and (ii) a speed vg of a gas flow on the raw material powder layer, comprising a memory; wherein the gas flow flows in a first direction parallel to a plane defined by the carrier, and the layer deposition mechanism is configured to move in a second direction orthogonal to the first direction, and the second direction is parallel to the plane defined by the carrier; device.

23. A device, in a method for controlling the irradiation beam for irradiating the raw material powder layer in a stereolithography process for manufacturing a three-dimensional workpiece, depositing the raw material powder layer on the carrier and / or on a preceding material layer on the carrier using the layer deposition mechanism; controlling the irradiation beam to irradiate at least a portion of the raw material powder layer within the irradiation area when a distance between the irradiation area and the layer deposition mechanism is greater than the threshold distance, wherein the threshold distance is (i) the moving speed of the layer deposition mechanism, and configured to perform a method comprising steps that depend on a velocity vg of a gas flow over the raw material powder layer The device according to claim 22 **Claim 24** In an apparatus for manufacturing a three-dimensional workpiece via a layer manufacturing method a carrier configured to accommodate a material for manufacturing the three-dimensional workpiece a material supply unit configured to supply material to the carrier and / or to one or more preceding material layers on the carrier a layer deposition mechanism for forming the supplied material into a material layer on the carrier and / or on one or more preceding material layers on the carrier a solidification device configured to solidify the material supplied to the carrier and / or to the one or more preceding material layers on the carrier for manufacturing the three-dimensional workpiece a gas supply unit configured to supply a shielding gas to a region of the material layer to be solidified by the solidification device a process chamber including the gas supply unit and the solidification device the device according to claim 22 An apparatus comprising **Claim 25** A device further comprising a computer program product including a program code portion for performing a method, the method comprising, when the computer program product is executed on one or more computing devices in a method for controlling an irradiation beam for irradiating a raw material powder layer in a layer manufacturing process for manufacturing the three-dimensional workpiece depositing the raw material powder layer on the carrier and / or on a preceding material layer on the carrier using the layer deposition mechanism controlling the irradiation beam to irradiate at least a portion of the raw material powder layer within an irradiation region when a distance between the irradiation region and the layer deposition mechanism is greater than a threshold distance, where the threshold distance is (i) a moving speed of the layer deposition mechanism, and (ii) a velocity vg of a gas flow over the raw material powder layer depending steps The apparatus according to claim 24, comprising

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