Method for planning the local solidification of a layer of powder material when manufacturing a three-dimensional object layer by layer
Patent Information
- Application Number
- EP2023730079
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-06-24
- Filing Date
- 2023-05-31
- Publication Date
- 2025-04-30
AI Technical Summary
During the layer-by-layer production of three-dimensional objects using a high-energy beam, there is a risk of local overheating in inskin and downskin areas, which can reduce buildability and increase processing time, and existing methods struggle to optimize vector patterns for simultaneous exposure of these areas without compromising quality or productivity.
Defining alternating blocks of inskin and downskin vectors and determining a sequence where inskin vector blocks and downskin vector blocks alternate, allowing for independent determination of patterns and optimizing vector orientation and density based on the geometry of each area to minimize heat exchange and prevent overheating.
This approach reduces the risk of local overheating, particularly in downskin areas, by allowing the downskin area to cool before processing the adjacent inskin block, thereby shortening or eliminating waiting times and ensuring high-quality, accelerated exposure of both areas without compromising processing quality.
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Abstract
Description
[0001] Method for planning the local solidification of a layer of powdered material in the layer-by-layer production of a three-dimensional object
[0002] The invention relates to a method for planning the local solidification of a layer of powdered material with a high-energy beam in the layer-by-layer production of a three-dimensional object, comprising the following steps: in a contiguous area of the layer in which a
[0003] Solidification of the powdered material with the high-energy beam is to take place, at least one inskin area and at least one downskin area is determined, For each Inskin area, an Inskin pattern is defined, which represents the geometric progression of a large number of Inskin
[0004] Vectors for the high-energy beam, and for each downskin area, a downskin pattern is defined, which defines the geometric progression of a plurality of downskin vectors for the
[0005] High-energy beam, wherein the definition of the Inskin pattern(s) within the at least one
[0006] Inskin area is independent of the definition of the downskin pattern(s) within the at least one downskin area;
[0007] Step A processing sequence of all inskin vectors and downskin
[0008] Vectors are defined.
[0009] Such a procedure is known from EP 3 563 203 B1, Fig. 4a therein. Methods for the layer-by-layer production of three-dimensional objects, also known as 3D printing, enable the manufacture of such objects with considerable design freedom and a comparatively short time expenditure. The objects are manufactured layer by layer from a powder, with the layers being locally irradiated with a high-energy beam for solidification. The movement of the high-energy beam on a layer to be processed during the manufacturing process is determined by vectors.
[0010] The layer to be processed is typically subdivided into parts in which the vectors and / or the associated parameters of the high-energy beam are selected differently. A distinction between in-skin regions and down-skin regions is important here. In the context of the application, an in-skin region is understood in particular to be a section of the layer to be processed that is positioned on a part of an underlying powder layer that is solidified during the production of the object. In the context of the application, a down-skin region is understood in particular to be a section of the layer to be processed that is positioned on a part of an underlying powder layer that remains unsolidified during the production of the object. Down-skin vectors are used to process a down-skin region.Accordingly, inskin vectors are used to process an inskin area, which can differ from the downskin vectors, for example with regard to their line energy or their length.
[0011] EP 3 563 203 B1, Fig. 4a therein, discloses a method for the layer-by-layer production of an object, wherein one layer of the object has a sandwich region and a downskin region adjacent to the sandwich region. A high-energy beam is initially guided along parallel hatch lines in one of these two regions to solidify the respective region. Subsequently, the high-energy beam is guided in a corresponding manner along parallel hatch lines in the other of the two regions to solidify the other region as well. Thus, the solidification of one region is completed before the solidification of the other region begins. Such a method is comparatively simple to implement.
[0012] If, during such layer-by-layer manufacturing of a three-dimensional object, all consecutive vectors are exposed directly one after the other with a high-energy beam in an in-skin area, or especially in a down-skin area, there is a risk of local overheating, which leads to reduced buildability. Overheating can be avoided by waiting times, but this increases processing time and reduces the productivity of the manufacturing process.
[0013] EP 3 563 203 B1, Fig. 4b therein, also discloses a method in which a high-energy beam is guided along continuous hatch lines across the boundary lines between a downskin region and a sandwich region. When switching between the downskin region and the sandwich region, the beam parameters of the high-energy beam are changed to adapt to the respective region. Such a method is intended to reduce thermal stresses at the interface between the downskin region and the sandwich region.
[0014] However, the use of continuous hatch lines requires the characteristics of both the downskin region and the sandwich region to be considered simultaneously when selecting vectors. The pattern of the vectors results from a compromise between the properties of the two regions. This makes it difficult to select vectors optimized for each region, for example, with regard to vector density. As a result, the downskin region is usually not processed optimally.
[0015] US 9676032 B2 relates to a method for the layer-by-layer production of a three-dimensional object, wherein a high-energy beam is used to expose a first region of a powder layer with parallel scan lines in a first direction, and a second region is exposed with parallel scan lines in a second direction. A scan line in the first region is exposed or melted immediately before a scan line in the second region. After applying another layer of powder, the first region is exposed on parallel scan lines in a third direction, and the second region is exposed on parallel scan lines in a fourth direction. This method is intended to reduce the time required to produce the object.
[0016] From DE 10 2017 126 624 A1, Fig. 12 therein, a selective coating in the overhang area in the generative manufacturing of three-dimensional components has become known, whereby in-skin patterns and down-skin patterns are planned together.
[0017] Object of the invention
[0018] It is the object of the present invention to provide a method for planning the local solidification of a layer of powdered material with a high-energy beam during the layer-by-layer production of a three-dimensional object, with which a high-quality, accelerated exposure of contiguous downskin areas and inskin areas can be carried out while avoiding overheating of these areas.
[0019] Description of the invention
[0020] This object is achieved according to the invention by a method according to claim 1. Advantageous embodiments emerge from the dependent claims.
[0021] The method according to the invention is characterized in that in step c) a plurality of inskin vector blocks and a plurality of downskin vector blocks are defined, wherein a respective inskin vector block comprises one or more of the inskin vectors which are to be processed consecutively, and a respective downskin vector block comprises one or more of the downskin vectors which are to be processed consecutively, and wherein a vector block sequence of processing the inskin vector blocks and the downskin vector blocks, hereinafter collectively referred to as vector blocks, is defined, in which inskin vector blocks and downskin vector blocks alternate.
[0022] The inventive alternating processing of the in-skin blocks and the down-skin blocks reduces the risk of local overheating of the contiguous layer area while saving waiting times. The down-skin region is particularly susceptible to local overheating because heat dissipation through unconsolidated powder in underlying layers is lower than through consolidated powder. The invention reduces the risk of overheating, particularly in the down-skin region, because the material in the down-skin region can cool down again after processing a down-skin block while the in-skin block following the down-skin block in the vector block sequence is being processed.Within the scope of the method, a time interval for cooling the downskin area after processing a downskin block is used at least partially for processing an inskin block, whereby waiting times during which the contiguous area of the layer is not exposed due to the risk of overheating can be shortened or even eliminated entirely. This accelerates the exposure of the contiguous area without reducing the quality of the processing of the inskin and downskin areas.
[0023] A vector (inskin vector or downskin vector) can be a straight section of the course of the high-energy beam point on the layer, or can be composed as a vector train of connected partial vectors, wherein the partial vectors in particular each represent straight sections of the course of the high-energy beam point on the layer, typically wherein successive partial vectors have a different direction of progression from one another.
[0024] Typically, a vector block comprises 1 to 10 vectors, often just a single vector or two vectors. For a typical object, typically at least 10, usually dozens or hundreds, in-skin vectors and at least 10, usually dozens or hundreds, down-skin vectors are formed per layer. Typically, at least 5, usually at least 10, in-skin vector blocks and at least 5, usually at least 10, down-skin vector blocks are formed for a contiguous area of the layer.
[0025] The definition of the inskin patterns and the downskin patterns is independent of each other in that no information about the inskin patterns (and in particular the position of individual downskin vectors) is required or applied for the definition of the downskin patterns (and in particular the position of individual downskin vectors), and vice versa. For the independent definition of the inskin patterns and the downskin patterns, knowledge of the geometry (extension / extent) of the corresponding inskin area or downskin area is essentially sufficient. It is possible, for example, to select completely different patterns for downskin and inskin (e.g., offset filling, stripe or checkerboard pattern). The independent definition of downskin and inskin patterns does not exclude the possibility that there are parameters that apply to both (and all other) patterns, e.g.the orientation of stripes formed by the vectors or the position of the origin from which the division of the area to be exposed into stripes begins. In particular, the inskin patterns and downskin patterns can be defined independently of one another by having adjacent inskin vectors in the inskin pattern at least predominantly at a different distance from one another than adjacent downskin vectors in the downskin pattern and / or by having the inskin vectors at least predominantly oriented obliquely to the downskin vectors.
[0026] The contiguous area to be exposed has a contour, and a contour scan of the high-energy beam can be performed as part of the manufacturing process. The contour scan is defined by one or more vectors arranged adjacent to the contour and aligned along the contour. In particular, exposure in the downskin region can include a contour scan and provide corresponding downskin vectors.
[0027] Preferred variants of the invention
[0028] A preferred variant of the method according to the invention is characterized in that in step c) the vector blocks are defined such that at least predominantly in each case two consecutive vector blocks in the vector block sequence a respective end point of the last vector of the earlier vector block in the layer is spatially spaced from a starting point of the first vector of the later vector block.
[0029] In this embodiment, the downskin region and the inskin region are alternately exposed, with a distance in the vector block sequence between the end point of the last vector of the earlier vector block in the layer and the starting point of the first vector of the later vector block, over which no irradiation by the high-energy beam takes place during the change between the vector blocks. In the context of the application, this is referred to in particular as discontinuous exposure. By sufficiently spacing the aforementioned end point and the aforementioned starting point, the heat exchange between a previously exposed sub-region and a subsequently exposed sub-region of the contiguous region is reduced. The powder in the contiguous region is heated only locally in a sub-region determined by a vector block and can cool down again relatively quickly.Locally limited heating prevents the high-energy beam from further heating a treated area that is already heated by heat flow from a neighboring area. The risk of local overheating is further reduced, and waiting times can be further reduced.
[0030] A variant of the method is advantageous in which, in step c), the vector blocks are defined such that, at least predominantly for two consecutive vector blocks in the vector block sequence, the direction of travel of a last vector of the earlier vector block in the layer is oblique to a direction of travel of the first vector of the later vector block. This allows the orientation of the vectors to be flexibly adapted to the shape of the connected region and the shape of the downskin and inskin regions. In particular, the vectors can be guided along corners or curves of an edge line of the connected region by their orientation. Alternatively or additionally, it is possible within the scope of the method to select a distance between adjacent downskin vectors that differs from a distance between adjacent inskin vectors.This allows the density of the downskin vectors and the inskin vectors to be adapted to the shape and extent of the downskin area and the inskin area.
[0031] In a further variant of the method according to the invention, the inskin vectors and the downskin vectors are defined such that at least predominantly the inskin vectors run obliquely to the downskin vectors. The course of the inskin vectors and the downskin vectors can thereby be adapted, in particular, to corners or curves at the interface between an inskin region and a downskin region.
[0032] An advantageous variant of the method according to the invention is characterized in that at least for a majority of the Inskin blocks for the respective Inskin vector block
[0033] - the inskin vector block contains at least a first inskin vector and a last inskin vector,
[0034] - and the contained inskin vectors are chosen such that a starting point of the first inskin vector lies near the end point of the last inskin vector, in particular wherein this starting point and this end point have a distance,
[0035] - which is smaller than 1 / 4 of the length of the longest Inskin vector of the Inskin vector block, preferably less than 1 / 10 of the length of the longest Inskin vector of the Inskin vector block, and / or
[0036] - which is smaller than 25 times the hatch distance in the inskin vector block, preferably smaller than 10 times the hatch distance in the inskin vector block, and / or
[0037] - which is smaller than 2.5 mm, preferably smaller than 1.0 mm.
[0038] This can help reduce unproductive downtime during layer exposure. Typically, downskin blocks to be processed consecutively are located close together, and inskin blocks to be processed consecutively are also located close together, and the downskin blocks are relatively small compared to the inskin blocks. By arranging the start / end points of the inskin blocks close to the downskin blocks (in a respective subperiod of the exposure of the contiguous area), the travel paths of the high-energy beam can be minimized when switching between the vector blocks in the vector block sequence.
[0039] In other words, the proximity of the start point of the first inskin vector to the end point of the last inskin vector allows the downskin vector block that is processed before the inskin vector block in question in the vector block sequence and the downskin vector block that is processed after the inskin vector block in question in the vector block sequence to be positioned close to each other. This eliminates the need to reposition the high-energy beam over long distances (after deactivation) when switching between the inskin vector block and the downskin vector blocks.
[0040] A further development of the aforementioned variant is characterized in that the starting point of the first inskin vector is adjacent to an interface between the associated inskin region of the inskin vector block and a neighboring downskin region, and in that the first inskin vector leads away from the starting point from the neighboring downskin region, and the last inskin vector leads back to the neighboring downskin region. As a result, after processing a downskin block of the neighboring downskin region, the high-energy beam is positioned comparatively close to the starting point of the first inskin vector of the inskin vector block of the inskin region and can be quickly guided to this starting point.After processing the inskin vector block associated with the first inskin vector, the high-energy beam is again positioned close to the adjacent downskin region and can be quickly guided to the next downskin vector block in the adjacent downskin region in the vector block sequence of processing.
[0041] A preferred variant of the method according to the invention is one in which, at least for a majority of the inskin blocks, a respective inskin block is formed by an even number, in particular two, four, or six, adjacent inskin vectors that have an alternating, opposite direction of extension, in particular wherein the inskin vectors run parallel to one another. The parallel alignment of the vectors is advantageously used for hatching to create a structurally simple hatching pattern, which serves to guide the high-energy beam during the exposure of the contiguous region. Due to the even number of vectors, the starting point of the first vector and the end point of the last vector can be close together, in particular if the adjacent inskin vectors are approximately the same length.
[0042] In a further variant, at least for some of the downskin vectors, the course of the respective downskin vector follows the course of a neighboring contour, in particular the outer contour, of the associated downskin region. This enables the downskin region to be processed in a simple manner by the high-energy beam along a contour of the downskin region, preferably traversing the contour in the form of contour runs, in particular along curves or corners of the contour in the downskin region. In particular, the downskin region can be grown outwards on a manufactured partial section of the inskin region, which is advantageous for rapid heat dissipation and the prevention of overheating. In this case, in particular for a contour section, a plurality of downskin vectors can be provided at different distances from the contour, which follow the course of the contour.
[0043] A variant of the method according to the invention is advantageous, which is characterized in that in step c) the inskin vector blocks and the downskin vector blocks are defined such that, at a respective interface section between an inskin region and a downskin region, first all inskin vectors that are at least partially located at or close to this interface section are processed, and then all downskin vectors that are at least partially located at or close to this interface section are processed. By processing an inskin region before an adjacent downskin region, the heat flow from the contiguous area is improved, since the heat can flow at least partially from the downskin region to the inskin region. From there, the heat flows away more effectively than directly from the downskin region, beneath which there is unsolidified (unmelted) powder.This method configuration enables faster cooling of an area (especially the downskin area) processed with the high-energy beam within the contiguous region. A vector is considered to be close to an interface section if, during the production of the vector, significant heat conduction occurs through the interface section. The length of the interface section can, for example, correspond to the length of neighboring downskin vectors.
[0044] A further development of the aforementioned variant is characterized in that downskin vectors located at least partially closer to the interface section are processed before downskin vectors located further away from the interface section. This ensures, during the processing of the downskin vectors, a bonding of the sub-regions of the downskin region to be exposed, determined by the downskin vectors, to an inskin region across the interface based on solidified powder. This leads to an improved heat flow from the downskin region via the inskin region during processing of the downskin region, in order to cool the downskin region more quickly.
[0045] In a preferred variant, within the scope of step c), waiting times are further defined at least between some consecutive vector blocks of the vector block sequence, during which the processing with the high-energy beam is to be paused. During these waiting times, the contiguous area cools down between processing with the high-energy beam to reduce the risk of overheating. Alternatively or additionally, waiting times can also be provided within the vector blocks.
[0046] A further variant of the method according to the invention is characterized in that at least some inskin vector blocks which follow one another in the vector block sequence alternating with downskin vector blocks are arranged adjacent to one another in the associated inskin region, and / or that at least some downskin vector blocks which follow one another in the vector block sequence alternating with inskin vector blocks are arranged adjacent to one another in the associated downskin region.
[0047] By sequentially processing adjacent vector blocks in the vector block sequence, connected regions of the contiguous area are processed, thus increasing the stability of the contiguous area during the processing process. In particular, the formation of island-like exposed regions surrounded by unexposed regions is avoided. Such island-like exposed regions can relatively easily change their position or orientation in an undesirable manner (for example, due to the different density and / or rigidity of the exposed regions relative to unexposed regions).
[0048] The scope of the invention also includes a computer program product which, when used on a control device of a 3D printing machine or a planning device, executes a method according to the invention as described above. Such a computer program product can be distributed separately from 3D printing machines or planning devices with little effort, wherein, after installation of the computer program product on a suitable control device of a 3D printing machine or a planning device, a planning method according to the invention can be carried out. Furthermore, the scope of the invention includes a control device of a 3D printing machine or a planning device that is programmed to carry out a method according to the invention as described above.The control device serves to control a 3D printing machine and, among other things, executes the planning method according to the invention, in particular according to the instructions of a previously mentioned computer program product. Alternatively, a planning device independent of a 3D printing machine (usually installed on a PC or server) can be used to execute the method according to the program; the result of the planning method is then passed on to an independent 3D printing machine for executing the construction process.
[0049] The scope of the invention further includes a method for the layer-by-layer production of a three-dimensional object, in which a local solidification of a powdery material is carried out successively in layers using a high-energy beam, wherein for at least some of the layers
[0050] - (step alpha) planning of the local consolidation in the layer is carried out according to a method according to the invention described above, and
[0051] - (step beta) the local hardening of the layer is carried out according to the planning according to step alpha by processing the inskin vectors and downskin vectors defined in step b) with the high-energy beam in the order defined in step c) of the planning for this layer.
[0052] By planning the exposure of the in-skin areas and down-skin areas in a contiguous region according to the invention, a high-quality, accelerated exposure of these areas can be carried out within the framework of the manufacturing process.
[0053] The invention also includes a 3D printing machine with a control device, wherein the control device is programmed to execute the aforementioned manufacturing method according to the invention on the 3D printing machine. Such a 3D printing machine is configured to plan and execute the exposure of the downskin areas and inskin areas in the contiguous region according to the invention in order to process these areas with high quality and at an accelerated rate, and in particular, without local overheating.
[0054] Further advantages of the invention will become apparent from the description and the drawings. Likewise, the features mentioned above and those further described can be used individually or in combination. The embodiments shown and described are not intended to be exhaustive, but rather are exemplary in nature for describing the invention.
[0055] Detailed description of the invention and drawing
[0056] Fig. 1 shows schematically a longitudinal section through an exemplary 3D printing machine for the layer-by-layer production of a three-dimensional object for the invention, wherein a high-energy beam exposes a layer to be processed;
[0057] Fig. 2 shows schematically a plan view of a first example of a continuous area of the layer to be processed, for the invention;
[0058] Fig. 3 shows schematically a plan view of a second example of a continuous area of the layer to be processed, for the invention;
[0059] Fig. 4 schematically shows a plan view of the second example of the connected region, showing only the inskin vectors and downskin vectors closest to a contour of the connected region; Fig. 5 schematically shows a plan view of a third example of a connected region of the layer to be processed, for the invention;
[0060] Fig. 6 shows schematically a plan view of the third example of one of the connected region of the layer to be processed for the invention, with downskin vectors and inskin vectors running parallel and adjacent to the contour of the connected region.
[0061] Fig. 1 schematically shows a longitudinal section through an exemplary 3D printing machine 1 for the layer-by-layer production of a three-dimensional object 2 for the invention. The object 2 is grown on a substrate 3a arranged on a lifting table 3 in a production chamber 4 of the 3D printing machine 1. The lifting table 3 enables vertical movement of the substrate 3a and the object 2. The object 2 is manufactured from powder layers 5a, 5b, 5c in the production chamber. To manufacture the object, the powder from the powder layers 5a, 5b, 5c is successively solidified locally using a high-energy beam 6 from the 3D printing machine 1. At the time point shown in Fig. 1, a (topmost) layer 7 of powder 8 to be processed is irradiated with the high-energy beam 6 as part of the manufacturing process in order to effect local solidification of the layer 7 to be processed.Unsolidified powder 8 is marked here by squiggles. Accordingly, the object 2 is formed layer by layer. The high-energy beam 6 is generated for this purpose in a beam source 16 and aligned by a mirror 17. The planned boundary 9 of the object 2 in the layer 7 to be processed is indicated in Fig. 1 by dashed boundary lines. The production process is controlled by a control device 10 of the 3D printing machine 1. The control device 10 is set up here to plan the local solidification with the aid of a computer program product 11 or its program for the layer 7 to be processed before this local solidification is carried out. In addition, the control device 10 also carries out the solidification of the respective layer to be processed. Alternatively, it is also possible to provide a separate planning device 29 on which the planned boundary 9 of the object 2 in the layer 7 to be processed is planned with the aid of a computer program product 11 or its program.whose program is used to plan the local hardening of layer 7 to be machined (shown in dotted lines); the planning device 29 then forwards the received planning to the control device 10, which then controls the actual hardening of layer 7.
[0062] When planning the local strengthening, a distinction must be made between downskin areas and inskin areas of object 2, with reference numerals 12a, 12b indicating exemplary downskin areas of layers 5b, 5c, and reference numerals 13a, 13b indicating inskin areas of layers 5b, 5c, which must be taken into account during the production of object 2 in layers 5b, 5c. Reference numeral 14 (I) denotes an exemplary downskin area of the layer 7 to be processed, while the reference number 15 (I) an inskin area of the layer 7 to be processed. The inskin areas 13a, 13b, 15 (I)usually require one of the Downskin areas 12a, 12b, 14 (I) different treatment during the local solidification of the respective layer with the high-energy beam 6, for example with regard to the position, orientation and density of the vectors and / or the beam parameters, in particular to avoid the risk of local overheating.
[0063] Fig. 2 shows schematically a plan view of a first example of a connected area 18 (I) the layer 7 to be processed (see Fig. 1), whereby in the contiguous area 18 (I) the layer 7 to be treated is to be exposed to the high-energy beam. The contiguous area 18 (I) consists (as shown in Fig. 2) of an Inskin area 15 (II) and a downskin area 14 (II) together. The downskin area 14(n) jst von jgpn inskin area 15 (II)separated by an interface 19 with interface sections, wherein in Fig. 2, an interface section 27a, which extends approximately over the longitudinal region of the downskin vector 2', and an interface section 27b, which extends approximately over the longitudinal region of the downskin vector 14', are shown by way of example. Towards the outside, the downskin region 14 (II) by a contour 20 (I) limited. When planning the consolidation of the contiguous area 18 (I) are used for the Inskin area 15 (II) Inskin vectors are defined, wherein in Fig. 2, the Inskin vectors 1', 3', 4', 6', 7', 9', 10', 12', 13' are identified by way of example. The Inskin vectors 1', 3', 4', 6', 7', 9', 10', 12', 13' determine the movement of the high-energy beam 6 during the exposure process in the Inskin region 15. (II) Accordingly, for the Downskin area 14 (II)Downskin vectors are defined, of which the downskin vectors 2', 5', 8', 11', 14' are shown as examples in Fig. 2. The downskin vectors 2', 5', 8', 11', 14' serve to determine the movement of the high-energy beam 6 during the exposure process in the downskin region 14 (II) Note that here the downskin vectors 2', 5', 8', 11', 14' each begin and end at radially outwardly directed marking lines in Fig. 2.
[0064] For the Inskin area 15 (II) Thus, an inskin pattern 21 is determined, which includes the inskin vectors 1', 3', 4', 6', 7', 9', 10', 12', 13' and, in particular, specifies the positions, lengths, and / or orientations of the vectors. The same applies to the downskin area 14. (II)A downskin pattern 22 is determined, which includes the downskin vectors 2', 5', 8', 11', 14' and, in particular, specifies the positions, lengths, and / or orientations. The inskin pattern 21 and the downskin pattern 22 are selected independently of each other during planning. This can be seen here, in particular, from the fact that the inskin vectors 1', 3', 4', 6', 7', 9', 10', 12', 13' run obliquely to the downskin vectors 2', 5', 8', 11', 14'.
[0065] Fig. 2 illustrates an exposure process of the contiguous area 18 (I)from a point in time at which the inskin vectors (not numbered) above the inskin vector marked 1' have already been processed. In the processing sequence of vectors 1' - 13', which was determined as part of the planning according to the invention, the vectors 1' - 13' are processed in ascending order according to their number. Several inskin vector blocks and downskin vector blocks are introduced in the processing sequence, with the inskin vector blocks 23a, 23b and the downskin vector blocks 24a, 24b being shown as examples in Fig. 2 (see dashed frames). The inskin vector blocks 23a and 23b each comprise two inskin vectors, 3', 4' and 6', 7' in Fig. 2 by way of example, whereas the downskin vector blocks 24a and 24b each comprise one downskin vector, 2' and 14' in Fig. 2 by way of example. The inskin vectors 1', 3', 4', 6', 7', 9', 10', 12', 13' and downskin vectors 2', 5', 8', 11', 14' are stored in their respective vector blocks 23a, 23b and 23c, respectively.24a, 24b as part of the consolidation of the contiguous area 18. (I) processed consecutively.
[0066] In the processing sequence, for alternating exposure of the Inskin area 15 (II) and the Downskin area 14 (II) Now, first, the inskin vector 1' is processed. Subsequently, the downskin vector 2' is processed in the downskin vector block 24a. After that, the inskin vectors 3' and 4' are processed in the inskin vector block 23a, with the high-energy beam 6 on the inskin vector 3' from the downskin region 14 (II) removed and then reattached to the Downskin area 14 on the Inskin vector 4' (II)Then, the downskin vector 5' is processed. Subsequently, the inskin vectors 6' and 7' are processed in the inskin vector block 23b. This is followed by the downskin vector 8'. Then, the inskin vectors 9' and 10' are processed. This is followed by the processing of the downskin vector 11', which corresponds to the contour 20. (I) is closest. The inskin vectors 12' and 13' are then processed. This is followed by the processing of the downskin vector 14' in the downskin vector block 24b.
[0067] The downskin vectors 2', 5', 8', 11' are manufactured one after the other (alternating with inskin vector blocks, including 23a and 23b) so that material is melted onto the interface section 27a from the inside outwards.
[0068] Because the inskin vectors 1', 3', 4', 6', 7', 9' and 10' have been processed before the downskin vector 14' is started, material can be melted onto the interface section 27b with the downskin vector 14', whereby the interface section 27b was already solidified.
[0069] In order to minimize the travel paths of the high-energy beam 6 (cf. Fig. 1), the inskin vectors 1', 3', 4', 6', 7', 9', 10', 12', 13' are selected here such that in an inskin vector block, for example in the inskin vector block 23a, a starting point 25 of a first inskin vector (in the processing sequence), here for example 3', lies near an end point 26 of a last inskin vector, here for example 4', in the respective inskin vector block 23a. In addition, the starting point 25 of the first inskin vector 3' is adjacent to the interface 19 between the associated inskin region 15 (II) the Inskin vector block 23a and the Downskin area 14(II) to enable a rapid change of the high-energy beam 6 (see Fig. 1) from the downskin area 14 (II) to the inskin vector block 23a. Here, the first inskin vector 3' leads from the starting point 25 from the adjacent downskin area 14 (II) away, whereas the last inskin vector 4' leads back to the adjacent downskin area 14(n), whereby the high-energy beam 6 quickly returns to the downskin area 14 after processing the inskin vector block 23a (II) The first and last Inskin vectors 3', 4' are antiparallel to an effective guidance of the high-energy beam 6, thus having an alternating opposite direction.
[0070] To the contiguous area 18 (I)In order to heat only locally during exposure, the vector blocks 23a, 23b, 24a, 24b are preferably defined in such a way that for each two vector blocks 24a, 23b following one another in the vector block sequence, a respective end point, here for example an end point 28 of the last vector 2' of the earlier vector block 24a is spatially spaced from a start point of the later vector block, here for example the start point 25 of the first vector 3' of the later vector block 23b.
[0071] Fig. 3 shows schematically a plan view of a second example of the connected area 18 (II) the layer 7 to be processed (see Fig. 1). The contiguous area 18 shown in Fig. 3 (II) is from an Inskin area 15 (III) and a first downskin area 14 (III) and a second downskin area 14 (IV) composed of the Inskin area 15 (III) border, with the Inskin area 15(III) here between the two downskin areas 14 (III) , 14 (IV) lies.
[0072] To guide the high-energy beam 6 (see Fig. 1), 15 (III) Inskin vectors are defined, some of which are labeled 1", 2", 4", 5", 8", for example, and in the downskin regions, downskin vectors are defined, some of which are labeled 3", 6", 7", 12", and 9", 10", 11". In this second example, some of the downskin vectors (for example, the downskin vectors 3", 6") run antiparallel to one another in order to enable effective guidance of the high-energy beam 6 (cf. Fig. 1). The downskin vectors 3'', 6'', 7'', 12'' and 9'', 10'', 11'' are aligned obliquely or perpendicularly to the inskin vectors 1'', 2'', 4'', 5'', 8'', whereby the downskin vectors 3'', 6'', 7'', 12'' and 9'', 10'', 11'' are selected in particular independently of the inskin vectors 1'', 2'', 4'', 5'', 8".
[0073] The inskin vectors are combined into inskin vector blocks, with inskin vector blocks 23c and 23d for the inskin vectors 1", 2", and 4", 5" being shown here as examples. Accordingly, the downskin vectors are combined into downskin vector blocks, of which a downskin vector block 24c for the downskin vector 3" is shown here as an example. The inskin vector blocks and the downskin vector blocks are processed alternately in a vector block sequence (not illustrated in detail; in particular, the numbering of the vectors here only partially corresponds to the processing sequence). The downskin areas 14 (III) , 14 (IV) and the Inskin area 15 (III) are together of a contour 20 (II) outlined.
[0074] Fig. 4 shows schematically a plan view of the second embodiment of the connected area 18 (II) , where only the contour 20 (II)The closest inskin vectors 1", 8" and downskin vectors 6", 7", 9", 10", 11", 12" are shown. These inskin vectors 1", 8" and downskin vectors 6", 7", 9", 10", 11", 12" can be used to define the contour 20 in a contour run defined by these vectors. (II) of the contiguous area 18 (II) to melt, if necessary again, after these vectors have already been melted during the exposure of the contiguous area 18 (II) were processed.
[0075] Fig. 5 shows schematically a plan view of a third example of a contiguous area 18 (III) the layer to be processed 7. The rectangular contiguous area 18 shown in Fig. 5 (III) is from an Inskin area 15 (IV) and a first downskin area 14 (V) and a second downskin area 14 (VI) composed, with the downskin areas 14 (V) , 14 (VI)here at opposite corners of the connected area 18 (III) are trained.
[0076] The downskin vectors, some of which are marked as 3'', 4'', 7'' and 8'' in Fig. 5, are in the respective downskin areas 14 (V) , 14 (VI) parallel to each other and diagonal to a contour 20 (III) of the contiguous area 18 (III) aligned, whereby two downskin vectors, for example the downskin vectors 3"', 4'" or 7"', 8"' are combined to form a downskin vector block, here for example the downskin vector blocks 24d and 24e. The downskin vectors 3"', 4'", 7'" and 8"' point to the contour 20 (III) of the contiguous area 18 (III) so that the high-energy beam 6 (see Fig. 1) when exposing the respective downskin area 14 (V) , 14 (VI) from the interior of the contiguous area 18 (III) to the contour 20 (III)in order to improve the mechanical stability and to enable better heat dissipation during the exposure of the downskin vectors 3'', 4'', 7'' and 8''. The inskin vectors, some of which are designated 1'', 2'', 5'' and 6'' in Fig. 5 by way of example, are aligned antiparallel in respective inskin vector blocks 23e, 23f, which allows efficient guidance of the high-energy beam 6 (cf. Fig. 1).
[0077] In the processing sequence, for an alternating exposure of the
[0078] Inskin area 15 (IV) and the Downskin area 14 (V) For example, first the inskin vectors 1"' and 2"' are processed in the inskin vector block 23e. Then the downskin vectors 3"', 4'" are processed in the downskin vector block 24d. This is followed by the processing of the inskin vectors 5"', 6'" in the inskin vector block 23f. After that, the downskin vectors 7"', 8'" are processed in the downskin vector block 24e.
[0079] Fig. 6 shows schematically a plan view of the third example of the connected area 18 (III) , where in the Inskin area 15 (IV) or the downskin areas 14 (V) , 14 (VI) Downskin vectors 9"' , 10"' and 13"' , 14"' and inskin vectors 11"' , 12"' and 15"' , 16"' parallel and adjacent to the contour 20 (III) of the contiguous area 18 (III) These vectors are in addition to the vectors shown in Fig. 5 in the connected area 18 (III) The high-energy beam 6 can be guided along the downskin vectors 9"', 10"' and 13"', 14"' and inskin vectors 11"', 12"' and 15'", 16"' shown in Fig. 6 in order to carry out a contour run and to determine the contour 20 (III) of the contiguous area 18 (III)to melt. This contouring typically occurs finally, after processing the vectors shown schematically in Fig. 5. The processing of vectors 9"' to 16'" occurs here in ascending order of their number.
[0080] Reference symbol list
[0081] 1 3D printing machine
[0082] 2 three-dimensional object
[0083] 3 lifting table
[0084] 3a Substrat
[0085] 4 Production chamber
[0086] 5a-5c Powder layers
[0087] 6 High-energy beam
[0088] 7 layer to be processed
[0089] 8 powders
[0090] 9 planned limitation in the layer to be processed
[0091] 10 Control device
[0092] 11 Computer program product
[0093] 11a Computer program product
[0094] 12a-12b Downskin areas of layers 5b, 5c
[0095] 13a-13b Inskin areas of layers 5b, 5c
[0096] 14 (I) (VI) Downskin area of the layer to be processed
[0097] 15 (I) (IV) Inskin area of the layer to be processed
[0098] 16 Beam source
[0099] 17 mirrors
[0100] 18 (I) (III) contiguous area
[0101] 19 Interface
[0102] 20 (I) - (III) contour
[0103] 21 Inskin patterns
[0104] 22 Downskin patterns
[0105] 23a-23f Inskin vector blocks
[0106] 24a-24e downskin vector blocks
[0107] 25 Starting point of a first Inskin vector
[0108] 26 Endpoint of a last Inskin vector
[0109] 27a, 27b Interface sections
[0110] 28 End point of the last vector of the previous vector block
[0111] 29 Planning facility 1' Inskin vector
[0112] 2' Downskin-Vektor
[0113] 3' - 4' Inskin-Vektor
[0114] 5' Downskin-Vektor
[0115] 6' - 7' Inskin-Vektor
[0116] 8' Downskin-Vektor
[0117] 9' - 10' Inskin-Vektor
[0118] 11' Downskin-Vektor
[0119] 12' - 13' Inskin-Vektor
[0120] 14' Downskin-Vektor
[0121] 1'' - 2" Inskin-Vektor
[0122] 3" Downskin-Vektor
[0123] 4" - 5" Inskin-Vektor
[0124] 6" Downskin-Vektor
[0125] 7" Downskin-Vektor
[0126] 8" Inskin-Vektor
[0127] 9'' - 12" Downskin-Vektor
[0128] Inskin-Vektor
[0129] 3'" - 4'" Downskin-Vektor
[0130] 5'" - 6'" Inskin-Vektor
[0131] 7'" - 10'" Downskin-Vektor
[0132] 11'" - 12'" Inskin-Vektor
[0133] 13'" - 14'" Downskin-Vektor
[0134] 15'" - 16'" Inskin-Vektor
Claims
Patent claims Method for planning the local solidification of a layer (5a, 5b, 5c, 7) of powdered material with a high-energy beam (6) during the layer-by-layer manufacturing of a three-dimensional object (2), comprising the following steps: Step a): in a contiguous area The layer (7), in which the powdered material is to be solidified with the high-energy beam, contains at least one in-skin area (15 (I)_(IV) ) and at least one downskin area (14 (I)_(VI) ) determined, step b): for each inskin area (15 (I) (IV) ) an inskin pattern (21) is defined, which is located in the inskin area (15 (I) (IV) ) defines the geometric path of a plurality of inskin vectors (1', 3', 4', 6', 7', 9', 10', 12', 13'; 1'', 2", 4'', 5'', 8''; 1''', 2''', 5''', 6"') for the high-energy beam (6), and for each downskin region (14 (I) (VI)) a downskin pattern (22) is defined, which is located in the downskin area (14) (I) (VI) ) defines the geometric path of a plurality of downskin vectors (2', 5', 8', 11', 14'; 3", 6'', 7", 9'', 10'', 11'', 12''; 3''', 4''', 7''', 8''') for the high-energy beam, wherein the definition of the inskin pattern(s) (21) within the at least one inskin region (15 (I) (IV) ) regardless of the determination of the downskin pattern(s) (22) within the at least one downskin area (14) (I) (VI) ) is done; Step c): A processing order of all inskin vectors (1', 3', 4', 6', 7', 9', 10', 12', 13'; 1'', 2'', 4'', 5'', 8''; 1''', 2''', 5''', 6''') and downskin vectors (2', 5', 8', 11', 14'; 3'', 6'', 7'', 9'', 10'', 11'', 12''; 3''', 4''', 7''', 8''') is defined, characterized in that in step c) a plurality of inskin vector blocks (23a, 23b, 23c, 23d) and a plurality of downskin vector blocks (24a, 24b, 24c, 24d, 24e) shall be determined, where each Inskin vector block (23a, 23b, 23c, 23d, 23e, 23f) represents one or more of the Inskin vectors (1', 3', 4', 6', 7', 9', 10', 12', 13'; 1", 2", 4", 5'', 8''; 1'', 2'', 5'", 6'"), which are to be processed sequentially, and each downskin vector block (24a - 24e) comprises one or more of the downskin vectors (2', 5', 8', 11', 14'; 3'', 6'', 7'', 9'', 10'', 11'', 12''; 3''', 4''', 7''', 8'''), which are to be processed sequentially, and wherein a vector block sequence for processing the inskin vector blocks (23a - 23f) and the downskin vector blocks (24a - 24e), hereinafter collectively referred to as vector blocks, is defined, in which inskin vector blocks (23a - 23f) and downskin vector blocks (24a - 24e) alternate.Method according to claim 1, characterized in that in step c) the vector blocks (23a - 23f; 24a - 24e) are defined such that at least predominantly in each pair of successive vector blocks (23a - 23f; 24a - 24e) in the vector block sequence, a respective endpoint (28) of the last vector (2') of the earlier vector block (24a) in layer (7) is spatially separated from a starting point (25) of the first vector (3') of the later vector block (23a). Method according to claim 1 or 2, characterized in that in step c) the vector blocks (23a - 23f; 24a - 24e) are defined such that at least predominantly in each pair of successive vector blocks (23a - 23f; 24a - 24e) in the vector block sequence the direction of a last vector (2') of the earlier vector block (24a) in layer (7) is oblique to a direction of the first vector (3') of the later vector block (24a). A method according to any of the preceding claims, characterized in that the inskin vectors (1', 3', 4', 6', 7', 9', 10', 12', 13'; 1", 2'', 4", 5'', 8''; 1"', 2"', 5''', 6''') and the downskin vectors (2', 5', 8', 11', 14'; 3'', 6", 7", 9'', 10", 11", 12"; 3"', 4"', 7"', 8"') are defined such that at least predominantly the inskin vectors (1', 3', 4', 6', 7', 9', 10', 12', 13'; 1", 2", 4", 5", 8"; 1"', 2"', 5"', 6"') run obliquely to the downskin vectors (2', 5', 8', 11', 14'; 3", 6", 7", 9", 10", 11", 12"; 3"', 4"', 7"', 8"'). Method according to one of the preceding claims, characterized in that at least for a plurality of the inskin blocks (23a - 23f) for the respective inskin vector block (23a - 23f) - the inskin vector block (23a - 23f) contains at least a first inskin vector (3', 6'; 1", 4"; 1'", 5'") and a last inskin vector (4', 7'; 2", 5"; 2"', 6"'), - and the contained inskin vectors (1', 3', 4', 6', 7', 9', 10', 12', 13'; 1", 2", 4", 5", 8"; 1"', 2"', 5"', 6"') are chosen such that a starting point (25) of the first inskin vector (3', 6'; 1", 4"; 1"', 5'") is close to the endpoint (26) of the last inskin vector (4', 7'; 2", 5"; 2"', 6"'), in particular wherein this starting point (25) and this endpoint (26) are spaced apart, - which is smaller than 1 / 4 of the length of the longest inskin vector (1', 3', 4', 6', 7', 9', 10', 12', 13'; 1", 2", 4", 5", 8"; 1"', 2"', 5"', 6"') of the inskin vector block (23a - 23f), preferably less than 1 / 10 of the length of the longest inskin vector (1', 3', 4', 6', 7', 9', 10', 12', 13'; 1", 2", 4", 5", 8"; 1"', 2"', 5'", 6'") of the inskin vector block (23a - 23f), and / or - which is smaller than 25 times the hatch spacing in the inskin vector block (23a - 23f), preferably smaller than a 10-fold hatch spacing in the inskin vector block (23a - 23f), and / or - which is smaller than 2.5 mm, preferably smaller than 1.0 mm. Method according to claim 5, characterized in that the starting point (25) of the first inskin vector (3', 6'; 1", 4"; 1"', 5"') is adjacent to an interface (19) between the associated inskin region (15 (I) (IV) ) of the inskin vector block (23a - 23f) to an adjacent downskin region Hegt, and that the first inskin vector (3', 6'; 1", 4"; 1"', 5'") from the starting point (25) from the adjacent downskin area (14 (I)_ (VI) ) leads away, and the last inskin vector (4', 7'; 2", 5"; 2'", 6'") to the adjacent downskin region (14 (I) (VI)) leads back. A method according to one of the preceding claims, characterized in that at least in a plurality of the inskin blocks (23a - 23f) a respective inskin block (23a - 23f) is formed by an even number, in particular two, four or six, adjacent inskin vectors (1', 3', 4', 6', 7', 9', 10', 12', 13'; 1'', 2'', 4'', 5'', 8"; 1'", 2''', 5''', 6''') which have an alternating opposite direction of travel, in particular wherein the inskin vectors (1', 3', 4', 6', 7', 9', 10', 12', 13'; 1", 2", 4", 5", 8"; 1"', 2"', 5"', 6"') run parallel to each other. Method according to one of the preceding claims, characterized in that at least some of the downskin vectors (2', 5', 8', 11', 14'; 3'', 6", 7'', 9", 10", 11", 12"; 3"', 4"', 7"', 8"') the path of the respective downskin vector (2', 5', 8', 11', 14'; 3", 6", 7", 9", 10", 11", 12"; 3"', 4"', 7"', 8"') the path of an adjacent contour (20 (I) (III)), in particular outer contour (20 (I) (III) ), of the associated downskin area (14 (I) (VI) ) follows. Method according to one of the preceding claims, characterized in that in step c) the inskin vector blocks (23a - 23f) and the downskin vector blocks (24a - 24e) are defined such that at a respective interface section (27a, 27b) between an inskin region (15 (I) (IV) ) and a downskin area (14 (I) (VI)) first, all inskin vectors (1', 3', 4', 6', 7', 9', 10', 12', 13'; 1", 2", 4", 5", 8"; 1"', 2'", 5'", 6'''), which lie at least partially on or near this interface section (27a, 27b), are processed, and then all downskin vectors (2', 5', 8', 11', 14'; 3'', 6", 7'', 9", 10'', 11'', 12"; 3'", 4'", 7'", 8'") which lie at least partially on or near this interface section (27a, 27b) are processed. . Method according to claim 9, characterized in that at least partially closer to the interface section (27a, 27b) Downskin vectors (2', 5', 8', 11', 14'; 3", 6", 7", 9", 10", 11", 12"; 3'", 4'", 7'", 8'") are processed before downskin vectors (2', 5', 8', 11', 14'; 3", 6", 7", 9", 10", 11", 12"; 3'", 4'", 7'", 8'") that are located further away from the interface segment (27a, 27b).Method according to one of the preceding claims, wherein in step c) waiting times are further defined at least between some successive vector blocks (23a - 23f; 24a - 24e) of the vector block sequence, during which the processing with the high energy beam (6) is to be paused. . Method according to one of the preceding claims, characterized in that at least some inskin vector blocks (23a - 23f), which alternate with downskin vector blocks (24a - 24e) in the vector block sequence, are adjacent to each other in the associated inskin region (15 (IHIV) ) are arranged, and / or that at least some downskin vector blocks (24a-24e) that alternate with inskin vector blocks (23a-23f) in the vector block sequence are adjacent to each other in the associated downskin area (14 (I) (VI)) are arranged. . Computer program product (11, 11a) which, when applied to a control device (10) of a 3D printing machine (1) or a planning device (29), executes a method according to one of claims 1 to 12. . Control device (10) of a 3D printing machine or planning device (29), programmed to execute a method according to one of claims 1 to 12. . Method for the layer-by-layer fabrication of a three-dimensional object (2), wherein a local solidification of a powdered material (8) with a high-energy beam (6) is successively carried out in layers (5a - 5c, 7), wherein for at least some of the layers (5a - 5c, 7) - (Step alpha) a planning of the local hardening in the layer (5a - 5c, 7) according to one of claims 1 to 12 is carried out, and - (Step beta) the local solidification of the layer (5a - 5c, 7) is carried out according to the plan according to step alpha by using the high-energy beam (6) to process the inskin vectors (1', 3', 4', 6', 7', 9', 10', 12', 13'; 1'', 2'', 4'', 5'', 8''; 1''', 2''', 5'", 6'''') and downskin vectors (2', 5', 8', 11', 14'; 3", 6", 7'', 9", 10'', 11'', 12"; 3'", 4'", 7'", 8'") defined in step b) in the sequence defined according to step c) of the plan for this layer (5a - 5c, 7). 3D printer (1) with a Control device (10), wherein the control device (10) is programmed to execute a method according to claim 15 on the 3D printing machine (1).