Method and control command generation unit for the automatic generation of control commands of an additive layer building device

Description

[0001] The invention relates to a method and a device for providing control commands for producing a number of three-dimensional objects using a generative layered construction device. Furthermore, the invention relates to a method and a device for producing the number of three-dimensional objects using the provided control commands.

[0002] Generative layered construction processes, such as laser sintering or melting, or stereolithography, are characterized by the fact that objects are produced layer by layer from a powdered or liquid build-up material. In each layer, the cross-sections of the objects in that layer are created by solidifying the build-up material. Production requires a computer-based three-dimensional representation of the objects, which can be created, for example, using a CAD design program.

[0003] The construction process typically takes place in a build chamber within the generative layered assembly device, from which the objects are removed after the manufacturing process is completed. For efficient use of the build chamber, the most compact arrangement of the objects to be manufactured within the build chamber is desirable. Preferably, related objects should be arranged adjacent to each other in the build chamber. To avoid the laborious task of a single person performing the assembly, WO 2011 / 100978 A1 proposes an automated assembly method.

[0004] When manufacturing objects, the initial goal is to achieve true-to-scale production according to the computer-based three-dimensional representation of the objects. However, size deviations can occur due to the construction process. On the one hand, the dimensions of the object can increase due to the fusion of the building material surrounding the object with the object. On the other hand, temperature fluctuations during the manufacturing process can lead to warping, and shrinkage can occur as a result of the solidification process. While such size deviations could be taken into account in advance by adjusting the computer-based three-dimensional representation of an object, this leads to problems when there are multiple objects in the build chamber, as the relative positions of the objects to one another change.

[0005] It is therefore an object of the present invention to provide a method and a device by means of which dimensional changes of objects as a result of the construction process can be taken into account without this having a significant impact on the construction process or the relative position of the objects to one another.

[0006] The object is achieved by a device for providing control commands according to claim 1, a method for providing control commands according to claim 2, a method for producing a number of three-dimensional objects by means of a generative layered construction device according to claim 11, a generative layered construction device according to claim 13, and a computer program according to claim 14. Further developments of the invention are specified in the dependent claims. A method according to the invention for providing control commands for producing a number of three-dimensional objects by means of a generative layered construction device, wherein in the generative layered construction device, the number of objects is produced layer by layer on a construction base by applying a layer of a formless construction material to the construction base or an already existing layer of construction material.

[0007] Typically, the computer-based model of the number of objects to be produced using the generative layered assembly device is a model created using a CAD design system in which a zero point (coordinate origin) is defined for each of the number of objects. According to the invention, for example, a common zero point is defined for the number of objects in the CAD coordinate system and then assigned to a specific location specified in build field coordinates on the build field. This allows a user to set up individual zero points (reference points for positioning) on ​​the build field of the generative layered assembly device. This makes it possible to precisely place the geometric data of components to be sintered at defined positions, and the relative position of the geometric data with respect to the zero point can be adopted in the CAD system.According to the invention, a number of objects are assigned a common reference location, in particular as a common coordinate origin. By creating such a common reference point for the geometric description of the number of objects, a relationship is established between the individual objects, which makes it possible to coordinate modifications to the geometric descriptions of the individual objects.

[0008] Preferred developments and embodiments of the invention can be found below or in the subclaims of the method according to the invention. Each feature mentioned below in connection with a claim category (method, control command generation unit, device, and computer program) can also be applied to any other claim category within the scope of the invention.

[0009] Preferably, the common reference location is a location on the build support or a location with a fixed position relative to the build support. The build support is a support arranged in a generative layered build device, usually in a build chamber, and movable perpendicular to the layers, or a plate or build platform arranged on it. In particular, the location with a fixed position relative to the build support can be a location in the build field of the generative layered build device, i.e., a location in the horizontal plane through the build chamber in which the solidification of the build material takes place. The reference location thus also serves to precisely assign the number of objects to a "build location" in the build field.

[0010] The arrangement is preferably based on a coordinate system that represents the geometry of the construction site, with the reference location being assigned to a defined location in the coordinate system. The coordinate system can, for example, be designed as a uniform grid.

[0011] Preferably, in the method according to the invention, in the step of modifying the computer-based model, the computer-based model is additionally converted into a modified computer-based model by rotation and / or centric stretching relative to a common transformation reference point for the number of objects.

[0012] By stretching the computer-based model to obtain a modified computer-based model, dimensional changes in objects caused by the construction process can be counteracted. In general, not only rotations and stretches are possible, but also centric affine transformations with a fixed point, preferably similarity transformations that leave the relationships between distances and angular sizes unchanged, as long as they are not identical transformations without modification, i.e., mappings of the computer-based model onto itself. It should also be noted that scaling (i.e., centric stretching) of three-dimensional objects is often used before their manufacture to compensate for the shrinkage to be expected in the respective layered construction process. Shrinkage and scaling are therefore factors in the dimensions of the three-dimensional object, which essentially cancel each other out as closely as possible, i.e.The centric stretching compensates for the expected shrinkage in advance. By selecting a common transformation reference point for the number of objects, it is possible to shrink and rotate all objects within the number of objects around a common reference point. This achieves a common shrinkage calculation as well as the same translation, rotation, and shrinkage for the entire number of objects.

[0013] The method can preferably be applied to cases in which a semi-finished part is arranged on the construction substrate, which is completed by manufacturing a number of objects on this semi-finished part. The rotation and / or centric stretching is then based on a common transformation reference point for the number of objects and the semi-finished part. By choosing a common transformation reference point, a displacement of the objects relative to the semi-finished part resulting from the transformation (rotation or centric stretching) is avoided. It should also be emphasized that it is of course also possible to choose different transformation reference points for different transformations.

[0014] Preferably, the transformation reference point is a geometric center point in the computer-based model, in particular a point of symmetry or a center of gravity. Using a geometric center point makes it possible to minimize distortions in the geometric description of the number of objects during a transformation, e.g., during a centric stretch.

[0015] In particular, the geometric center point can be a center point defined by one or more bounding boxes surrounding the objects, in particular minimally surrounding cuboids. The bounding box can also be a three-dimensional structure constructed in such a way that a two-dimensional figure surrounding an object cross-section in a selected layer, e.g., a rectangle minimally surrounding the cross-section, is extended in the direction perpendicular to the cross-section. The geometric center point can, in particular, be the center of a bounding box.

[0016] Preferably, the transformation reference point is a point of symmetry or center of gravity of one of the objects, or a geometric center of its enclosing body. This simultaneously selects one of the objects as the master part, relative to which a transformation of the computer-based model of the remaining objects takes place. This is defined and used as a kind of initial object for scaling or orientation.

[0017] Preferably, the transformation reference point is chosen so that it coincides with the common reference location. If both scaling and (re-)orientation of a number of objects are to be performed, it can be very advantageous to use a first transformation reference point for the scaling and a second transformation reference point, different from the first, for the orientation. In this case, it is more preferable to first perform the orientation based on the second transformation reference point and then perform the scaling. However, choosing the common reference location as the transformation reference point considerably simplifies the implementation of a transformation without significantly affecting the construction process or the relative sizes of the objects.

[0018] In a modification of the method according to the invention, an additional check is carried out to determine whether there are any overlaps between objects or their envelopes in the modified computer-based model. If this is the case, the objects in question are moved in the model until there is no longer any overlap. Even when scaling is carried out using a common transformation reference point for the number of objects, the dimensional changes to the objects can lead to them colliding (overlapping) in the modified computer-based model. If an object overlaps with other objects and / or with a specified measurement point in the construction field and / or with a boundary of the construction field, a warning message can be initiated and / or an automatic rearrangement of objects in the construction field can be carried out.Alternatively or additionally, the warning message can be issued to a user who then carries out such a reordering independently, but preferably again with algorithm support.

[0019] The invention can preferably be used in connection with generative layered construction devices in which a construction base is used that is suitable for being removed from the generative layered construction device after completion of the manufacturing process, together with the manufactured number of objects, and for being inserted into a further processing device for further processing of at least one, preferably all, of the manufactured number of objects. In the further processing device, the construction base, e.g., a platform, can also serve as a processing base for supporting the objects to be further processed during further processing.In such a case, the reference location and / or the modified model of the objects to be further processed, in which a location is defined as a common reference location, in particular as a common coordinate origin, for the geometric description of the objects to be further processed, is preferably transmitted to the further processing device. Such subsequent processing could include, for example, milling, spark erosion, grinding, polishing, and much more, which would be carried out subsequently after completion of the generative layer building process. Since the same reference location is used as a basis for further processing, calibration of the further processing device is not necessary, especially if the reference location has a fixed position relative to the construction document.For example, if the coordinate origin defined in the CAD coordinate system for the geometric description of the number of objects is assigned to a reference location on the construction document, then a milling machine used for further processing of objects, for example, in which the construction document including the objects is inserted, can continue to reference the same geometric description of the objects as the generative layered construction device without a complex adjustment process. This makes further processing much easier, faster, and, above all, more accurate.

[0020] If the invention is used in connection with generative layered construction processes in which a semi-finished part is used as the construction base, which is completed by producing a number of objects on this semi-finished part, then in this case, the same location that was selected as the reference location for the semi-finished part in a previous manufacturing process can preferably be selected as the reference location. If such a reference location is adopted from an upstream manufacturing process, this is very advantageous because the same location information (reference locations) can then be used in both manufacturing processes (upstream process and generative layered construction process) in the sense of a common coordinate or orientation system.This makes calibration of the generative layer building device, if necessary at all, very simple and the generative layer building process can be carried out more easily, quickly and, above all, more accurately.

[0021] Particularly preferably, the method according to the invention runs fully automatically, i.e., without any necessary user input. This leads to an acceleration and simplification of the generative layering process.

[0022] The model data access unit can be an input interface that can read data from a mobile data storage device, receive data via a network, or read data directly from a database. Since the device for providing control commands can be implemented not only as a separate unit, but can also be part of a more comprehensive IT system (e.g., a CAD design system or an object property simulation system) or a generative layered construction device, the model data access unit can also be merely a software interface that communicates with the other system components. The network can be a LAN or the Internet, whereby the data can also be transmitted to a layered construction device that is spatially distant from the device for providing control commands.In particular, if the device for providing control commands is integrated into a generative layered construction device, data transmission via a bus system or a shared memory is also possible. In a preferred embodiment of the device for providing control commands according to the invention, the model modification unit (102) is designed to additionally convert the computer-based model into a modified computer-based model by rotating and / or centrally stretching it relative to a common transformation reference point for the number of objects. Fig. 1 shows a schematic representation of a generative layer building device using the example of a laser sintering device. Fig. 2 shows a schematic plan view of a part of a construction field of a generative layer building device to explain a first embodiment of the method according to the invention. Fig. 3 shows the structure of an embodiment of a device according to the invention for providing control commands. Fig. 4 shows a schematic perspective view of a model of a three-dimensional object to be produced on a base for production according to a second embodiment of the method according to the invention. Fig. 5 shows a plan view of the model of Fig. 4 .

[0023] In connection with the description of the invention, it should be noted that the term "zero point" is to be understood as a synonym for the term "reference location" otherwise used throughout here, in the sense of an essentially point-like reference location. The term "component" or "part" stands for a three-dimensional object to be produced. Furthermore, the term "group" is sometimes used synonymously instead of the term "number". For a description of the method according to the invention, an inventive generative layer construction device will first be described below using the example of a laser sintering or melting device with reference to Fig. 1 be described.

[0024] For building an object 3, the laser sintering or laser melting device 1 contains a process chamber or construction chamber 2 with a chamber wall 4.

[0025] An upwardly open container 5 with a container wall 6 is arranged in the process chamber 2. The upper opening of the container 5 defines a working plane 7, wherein the area of ​​the working plane 7 located within the opening, which can be used to build the object 3, is referred to as the build field 8.

[0026] Arranged within the container 5 is a carrier 10 movable in a vertical direction V, to which a base plate 11 is attached, which closes off the container 5 at the bottom and thus forms its base. The base plate 11 can be a plate formed separately from the carrier 10 and fastened to the carrier 10, or it can be formed integrally with the carrier 10. Depending on the powder and process used, a construction platform 12 can be attached to the base plate 11 as a construction base, on which the object 3 is built. However, the object 3 can also be built on the base plate 11 itself, which then serves as the construction base. Fig. 1 the object 3 to be formed in the container 5 on the construction platform 12 is shown below the working level 7 in an intermediate state with several solidified layers, surrounded by unsolidified building material 13.

[0027] The laser sintering device 1 further includes a storage container 14 for a powdered build material 15 that can be solidified by electromagnetic radiation, and a coater 16 movable in a horizontal direction H for applying the build material 15 within the build field 8. Optionally, a radiant heater 17 is arranged in the process chamber 2, which serves to heat the applied build material 15. An infrared radiator, for example, can be provided as the radiant heater 17.

[0028] The laser sintering device 1 further comprises an exposure device 20 with a laser 21 which generates a laser beam 22 which is deflected via a deflection device 23 and focused onto the working plane 7 by a focusing device 24 via a coupling window 25 which is mounted on the top side of the process chamber 2 in the chamber wall 4.

[0029] The laser sintering device 1 further includes a control device 29, via which the individual components of the device 1 are controlled in a coordinated manner to carry out the construction process. Alternatively, the control device can also be mounted partially or entirely outside the device. The control device can include a CPU whose operation is controlled by a computer program (software). The computer program can be stored separately from the device on a storage medium, from which it can be loaded into the device, in particular into the control device.

[0030] The control device 29 is controlled via a control command set that contains, among other things, data containing the structure of the number of objects to be manufactured, in particular a three-dimensional CAD layered model of the objects with information about the respective cross-section of an object in each layer of the build material to be solidified, and data that defines the precise parameters for solidifying the build material. In particular, the data contains precise information about each layer to be solidified during the production of the number of objects.

[0031] During operation, the control device 29 lowers the carrier 10 layer by layer, controls the coater 16 to apply a new powder layer, and controls the deflection device 23 and, if appropriate, also the laser 21 and / or the focusing device 24 to solidify the respective layer at the locations corresponding to the respective object by means of the laser beam 22 in the construction field 8.

[0032] Any powder or powder mixture suitable for the laser sintering or melting process can be used as powdered buildup material. Such powders include, for example, plastic powders such as polyamide or polystyrene, PAEK (polyaryl ether ketone), elastomers such as PEBA (polyether block amide), plastic-coated sand, ceramic powder, or metal powders such as stainless steel powder or other metal powders adapted to the respective purpose, especially alloys.

[0033] The generative layered construction device according to the invention additionally contains a device for providing control commands 100, which is described further below. This device for providing control commands 100 supplies the control device 29 with control commands, which are used by the control device 29 when carrying out the manufacturing process of an object.

[0034] In addition to laser sintering, the generative layer building processes covered by the invention also include the laser melting process, mask processes in which masks are used to selectively solidify a material layer, 3D printing processes, stereolithography processes, etc. The generative layer building device described above as an example naturally has a different structure known from the prior art if the process is not a laser sintering or melting process. Likewise, a generative layer building device according to the invention for a laser sintering or melting process also includes apparatus modifications compared to the example described above, provided that a device for providing control commands 100, described further below, which can also be a component of the control device 29, is present.In addition to at least one build-up means for the generative layer-based production of three-dimensional objects, the invention comprises a control command generation unit according to the invention or a data connection to such a control command generation unit. Build-up means refers to all those, in particular mechanical and / or optical devices, that are used in a layer-building process such as selective laser sintering or similar well-known layer-building processes, for example, coaters for build-up materials, lasers or other radiation or particle sources for the targeted direction of energy to specific points on the build-up material, optical elements, and much more.The device described in DE 195 14 740 C1, with all its physical components, can be considered as an exemplary reference for a device for carrying out a generative layer construction process for producing a number of three-dimensional objects and for the construction means contained therein. The disclosure of this document is hereby understood as part of the disclosure of the present application.

[0035] In a generative manufacturing process, in which objects are produced layer by layer from a building material, a computer-aided model (CAD model) of the object to be produced is initially available. A control command set for the control device 29 provides the control device 29 with specific information regarding how the solidification should proceed for each point in a layer to be selectively solidified, with reference to the computer-aided model (CAD model) of the object to be produced. In the case of a laser sintering or melting process, this includes, for example, information about the laser intensity, the laser beam diameter, the order in which the individual points of the layer are solidified, any offset of the laser beam from the contour of a region of a layer to be solidified (beam offset), etc. First embodiment

[0036] A first embodiment of the invention will be described below with reference to Fig. 2 and 3 described. Fig. 2 shows a plan view of a part of a build field of a generative layer building device during the generative production of a number of (in this example 5) objects 3, 301, 302, 303 and 304.

[0037] To produce the objects, a control device 29 of the generative layered construction device is controlled via a control command set, which contains, among other things, a three-dimensional CAD layered model of the objects with information about the respective cross-section of an object in each layer of the building material to be solidified and data that defines the precise parameters for solidifying the building material. Such a control command set is obtained on the basis of a computer-based model of the number of objects, which was created, for example, using CAD software. To obtain the control command set, control commands are provided by a device for providing control commands 100, which in Fig. 3is shown schematically. Such a device for providing control commands 100 can be a correspondingly programmed computer, or the device can be implemented by means of software that runs, for example, on the CAD design computer for the number of objects or the control device 29.

[0038] The device for providing control commands 100 has a model data access unit 101, by means of which the computer-based model of the number of objects 3, 301, 302, 303, and 304 is accessed. The model data access unit is, for example, a software or hardware interface by means of which access to the model data stored in the memory of a CAD design computer is possible (possibly via a network). The model data access unit 101 can equally well be a reader that reads the model data stored on a mobile data storage device.

[0039] The model data access unit 101 feeds the model data to the model modification unit 102, which proceeds as follows when modifying the model data: First, the model data of the entire number of objects 3, 301, 302, 303, and 304 are linked to a common reference location on the construction site. This provides a geometric description of the model data of the objects in the construction site coordinate system. In particular, when using a grid arrangement of the objects on the construction site, as shown in Fig. 2 As shown, the transition to construction site coordinates is advantageous, since in the modified computer model the objects are then assigned to fixed positions on the construction site with the specified grid spacing. In the example, the procedure is as follows: In the construction site coordinates, a grid 110 consisting of (in Fig. 2) horizontal lines 110x and vertical lines 110y are created. Each intersection point of a horizontal line 110x with a vertical line 110y is assigned a grid point 115, which is a potential location for an object. In the example, each of the objects 3, 301, 302, 303, and 304 is arranged on such a grid point 115 in the build field (e.g., by assigning the grid point at which object 3 is arranged to the entire number of objects as a common reference point, and by specifying the distances between the objects in the build field coordinate system such that each of the objects 301, 302, 303, and 304 lies on a grid point). "Arranging on a grid point" means that the origin of the CAD model of a component in component coordinates is assigned to the build field coordinates of a grid point 115.

[0040] It should be noted that, of course, an arrangement grid can be omitted or a different geometry of the grid (not necessarily a rectangular grid) can be chosen, as long as a common reference location is assigned to the number of objects.

[0041] If a platform is used as the build support that can also be used in processing devices other than the generative layered assembly device, the particular advantage of using build field coordinates becomes apparent: If a play-free arrangement of the platform in the respective devices is ensured (e.g., using a commercially available clamping system), then separate adjustment processes do not have to be carried out in the individual devices (e.g., a milling device in which the manufactured objects are post-processed, or a device in which semi-finished parts are produced that are then completed using the generative layered assembly device). Due to the play-free arrangement of the platform in the respective processing devices, there is a fixed relationship between a device coordinate system and the platform coordinates.It is then sufficient to specify the machining operations with reference to the platform coordinates without performing a complex adjustment process.

[0042] The reference location can optionally be determined based on an at least partially automatic definition algorithm. Such a definition algorithm preferably determines the reference location based on a criteria database. The criteria database preferably contains at least one of the following criteria: a collision criterion that initiates a warning message when an object overlaps with other objects and / or with a specified measuring point in the construction field and / or with a boundary of the construction field, on the basis of which an automatic rearrangement of objects in the construction field is preferably carried out), a component-specific criterion that queries component-specific arrangement requirements for an arrangement of the component in the construction field and optimises the arrangement of the component accordingly, a material-specific criterion that takes specific properties of a construction material into account for determining the reference location, a grid criterion that automatically determines the reference location using a point grid stored in the grid criterion.

[0043] According to one aspect of the invention, the reference location can also be defined at least partially in a user-defined manner based on user interaction. For example, if an object overlaps with other objects and / or with a specified measurement point in the construction field and / or with a boundary of the construction field, the model modification unit 102 can optionally issue a warning message to a user, who then automatically, but preferably again with algorithmic support, rearranges the object(s). Furthermore, the model modification unit 102 can optionally automatically define the reference location as a point in the point grid that is closest to a user-defined location – this can be understood as a type of "snap function," i.e., an automatic object movement based on a grid to points of the grid specified by a user. For this purpose, an input option can be created for the user, e.g.A table with the coordinates of the selectable grid points, which allows a part to be freely placed on one of these points. This is done using a snap function.

[0044] To compensate for dimensional changes of the objects compared to the original CAD model, which can be caused by the generative layering process, the model modification unit 102 subjects the original CAD model of the number of objects to scaling (centric stretching). In particular, a common transformation reference point (fixed point of the centric stretching) is selected for all objects. The reason for this is that the centric stretching also changes the distances between the objects, and these distance changes are different for different positions of the transformation reference point. On the one hand, distance changes can have the disadvantageous effect that objects overlap with one another after scaling, i.e., are no longer separate from one another. On the other hand, the objects can move away from their grid points as a result of the distance changes.Especially in the case of a platform that is also used in a post-processing device after generative manufacturing, this leads to complex readjustment processes in the post-processing device.

[0045] The choice of a suitable common transformation reference point usually depends on the geometry (especially the symmetry) of the objects or their arrangement. In the example of the Figure 2 Grid point 115, on which the central object 3 is located, would be a suitable transformation reference point for scaling. Firstly, the distances of objects 301, 302, 303, and 304 from the central object 3 change in the same way. However, if an overlap is to be avoided precisely at the point where objects 3 and 301 intersect, then point 320 could also be selected as the transformation reference point.

[0046] The transformation reference point can be defined at least partially in a user-defined manner based on user interaction. Likewise, the reference location can be determined automatically or semi-automatically based on at least one determination algorithm. In this case, it is preferred that the determination algorithm determines the reference location based on a criteria database in which at least one of the following criteria is stored: a mean location criterion that determines a mean location from the computer-based model of at least one three-dimensional object, which is preferably selected from a center point, a center of gravity, a middle line point of a line representing the object, in each case in relation to the object and / or to a specific (selected) layer thereof, which layer forms the basis of the layer construction method; an outline criterion that determines an outline from the computer-based model of at least one three-dimensional object, in relation to the object and / or to a specific (selected) layer thereof, which layer forms the basis of the layer construction method. a function criterion that assigns a special function to a location and / or functional area of ​​the object. Such a function can, for example, result from the shape of the location orfunctional area, but also from its position in relation to the three-dimensional object to be manufactured or in relation to other objects to be manufactured. For example, a recess in a functional area of ​​the component can have a fixing function, from which it can be deduced, for example, that the recess must be positioned very precisely during generative manufacturing and should remain essentially stationary even when the object is scaled. Such requirements for stationary location can also be derived from other locations or functional areas.

[0047] For the automatic determination of a transformation reference point, it may be advantageous to use the shape and position of a bounding box surrounding the object, particularly a cuboid associated with the object and minimally surrounding it (in other words, the shape and position of its bounding box), rather than the true shape of an object when determining a mean location or geometric center. Under certain circumstances, it may also be advantageous to use the bounding box surrounding a plurality of objects as the basis for determining a mean location or geometric center.

[0048] As can be seen from the example of Fig. 2 recognizes, it can also be advantageous to select a master part from the number of objects (in the Figure 2 the object 3) and to select a transformation reference point and / or the reference location in such a way that only the properties of the master part are taken into account (i.e. its symmetry, etc.).

[0049] Finally, the control command generation unit 103 generates control commands for a control command set for producing the number of objects using the generative layered construction device based on the computer-based model modified by the model modification unit 102. The control commands can either be integrated into a control command set by the device for providing control commands itself, or this final step can be performed in a separate device, e.g., the control device 29.

[0050] The number of objects can be a related group of objects to be manufactured or the total number of objects to be manufactured with the generative layered building device in one construction process. Second embodiment

[0051] A second embodiment of the invention will be described below with reference to Figs. 4 and 5 described. The Figures 4 and 5show a model (for example, stored in the form of a CAD file) of a component 3, i.e., a three-dimensional object 3 to be manufactured, which is to be produced on a semi-finished part arranged on a base, a so-called preform 120, using a generative layering process, for example, direct metal laser sintering. The preform 120 is a component manufactured in a manufacturing process preceding the generative layering process, for example, a CNC-milled component or similar. Such preforms are used, for example, in tool manufacturing and, as semi-finished parts, serve as the basis for a hybrid component, the inner and outer contours and functions of which are significantly shaped by the post-processing in the generative layering process.

[0052] The component 3 is to be built onto this preform 120, so that the entire manufacturing process comprises a hybrid manufacturing process, from which a hybrid component 150 is then created, consisting of the preform 120 and the component 3, which are firmly connected to one another by the generative layer construction process. The preform 120 is designed here, for example, as a rectangular part of uniform height and has an upper side O 1 and a lower side U 1. The component 3 itself is also rectangular and of uniform height and has an upper side O 3 and a lower side U 3. Four recesses in the form of bores are already provided in the preform 120. Their shape and arrangement correspond to analogous recesses in the component 3, which continue the bores in the preform upwards, resulting in a total of recesses B 1 , B 2 , B 3 , B z .The recesses B 1 , B 2 , B 3 , B z thus extend from the top side O 3 to the bottom side U 3 of the component 3 and continue directly from the top side O 1 to the bottom side U 1 of the preform 120. The three recesses B 1 , B 2 , B 3 are each positioned in a region of corners of the component 3; the recess B z, however, is a central recess in the middle of the component 3.

[0053] Within the scope of the invention, the CAD model of the component 3 is first modified such that a location on a construction field of the generative layer construction device (not shown), at which the component 3 is to be generatively manufactured or the preform 120 is to be placed, is a reference location for the geometric description of the component 3. Preferably, a location on the preform 120 is selected as the reference location, whereby the geometric description of the component 3 is linked to positions on the surface of the preform 120. Furthermore, the preform 120 is preferably attached to a predefined location on the construction substrate, whereby a predefined location on the preform 120 is linked to the predefined location on the construction substrate, so that there is a common coordinate system for describing locations on the preform 120 and locations on the construction substrate.

[0054] Next, transformation reference points are defined for scaling (centric stretching) the data of component 3 and rotating component 3 and preform 120 on the build area. Fig. 5It can be seen that in the present example, two different transformation reference points R rot and R skal are present, whereby the first transformation reference point R skal serves to scale the component 3 larger, for example, within the scope of shrinkage compensation. All scaling arrows Skal therefore point in the radial direction away from the first transformation reference point R skal , which is positioned (i.e. determined) exactly in the middle of the central recess B z. This ensures that the shrinkage compensation is carried out evenly along each line or section from the central recess B z towards the outer boundaries of the component 3. This ultimately results in a shrinkage compensation that is true to scale with respect to the preform 120. This ultimately ensures that after the generative layer construction process has been carried out, the uninterrupted rectilinear (i.e.general: intended) course of all recesses B 1 , B 2 , B 3 , B z from the underside U 1 to the top side O 3 is guaranteed. If, on the other hand, scaling were to be carried out from a different transformation reference point than that shown here, displacements of the recesses in component 3 relative to those in preform 120 would be preprogrammed. The choice of the transformation reference point R skal intended for scaling is essentially component-dependent, i.e. dependent on its respective geometry and / or assignment to other corresponding parts, such as preform 120 here.

[0055] In contrast, the second transformation reference point R rot , which is arranged in the center of the third recess B 3 , serves as the center of a rotation of component 3 and preform 120 on the construction field along a rotation direction Rot, with the purpose of orienting the two accordingly during generative layer construction.

[0056] Preferably, the component is first oriented, ie rotated along a rotation axis defined by the transformation reference point R rot, here extending perpendicularly into the figure, along the rotation direction Rot and then scaled as described above.

[0057] It would also be possible to select a common transformation reference point for scaling and rotation, which would then serve as a fixed point for the final rotational stretching. It is important that the transformation reference point for the stretching is a point that would be selected in the same way for stretching preform 120 due to the identical symmetry properties of preform 120 and component 3 (here, in particular, the position of the interacting (corresponding) sections of component 3 and preform 120, i.e., in this example, the position of the recesses (holes) B 1 , B 2 , B 3 at the corners). In particular, the reference location on the build site can also be identical to a transformation reference point, which simplifies the definition of the modified CAD model of component 3 (i.e., the CAD model after its scaling and / or rotation).

[0058] Based on the Figures 4 and 5An embodiment with a preform 120 was described. Such a hybrid process does not necessarily have to be carried out; it also happens that components are built that are supported by so-called supports, i.e. a structure that lies below the actual component in the generative layer construction process (i.e. between the component and a base of the construction field (such as a construction platform) and that serves as a support structure for the component during the construction process. In this case, the supports can be viewed as belonging to the number of objects described in the first embodiment, and the procedure is as described in the first embodiment, with the exception that an object and the associated support may be assigned to the same grid point 115 in the construction field.

[0059] Furthermore, all possible modifications described in connection with the first embodiment can also be applied in the same way to the second embodiment. In particular, a plurality of objects can also be produced on a preform 120.

[0060] It is emphasized again that the embodiments described here can be used individually or combined with one another in any way. The term "one" generally includes "multiple" as an option, unless it is explicitly specified as "single" or "exactly one." A unit may also comprise multiple subunits, which may also be physically separated from one another. "Number" is understood to mean "one or more"; "plural" is understood to mean "more than one."

[0061] Finally, it should be mentioned that the individual components 101 to 103 of the device for providing control commands can be implemented either using hardware or as pure software modules or as a mixture of hardware and software. Interfaces, in particular, do not necessarily have to be designed as hardware components, but can also be implemented as software modules, for example, if the data fed in or output via them can be taken over by another component already implemented on the same device or only need to be transferred to another component via software. Likewise, the interfaces can consist of hardware and software components, such as a standard hardware interface that is specially configured by software for the specific application.In addition, several interfaces can also be combined into a common interface, for example an input-output interface.

Claims

1. A device for providing control commands for the production of a plurality of three-dimensional objects (2) by means of an additive layer-wise building device, wherein the plurality of objects is produced layer by layer in the additive layer-wise building device by applying each time a layer of a shapeless building material on a building base or an already existing building material layer and solidifying said layer at positions that correspond to the cross-section of an object by supplying energy radiation or a binder at said positions in a build area of the additive layer-wise building device, wherein the device comprises at least: a model data access unit (101) that is configured to access model data of a computer-based model of the plurality of objects, which model geometrically describes the objects, wherein for each of the objects a coordinate origin is defined in the computer-based model, a model modification unit (102) that is configured to modify the model data of the computer-based model in such a way that for the geometric description of the plurality of objects a location is defined as a common coordinate origin, wherein the common coordinate origin is assigned to a specific location specified in build area coordinates in the build area, and wherein the respective coordinate origin of each of the objects in component coordinates is assigned to the build area coordinates of a grid point in the build area, and / or wherein the specified location is a location on the building base or a location having a fixedly predetermined position relative to the building base, a control command generating unit (103) that is configured to generate control commands of the additive layer-wise building device for a set of control commands for the production of the plurality of objects by means of the additive layer-wise building device based on the modified computer-based model, such that the set of control commands includes data for each layer to be solidified in the manufacture of the plurality of objects, which data defines the exact parameters for solidifying the building material.

2. A method to be carried out by a device according to claim 1, the method comprising at least the following steps: a step of providing a computer-based model of the plurality of objects, which model geometrically describes the objects, wherein a coordinate origin is defined in the computer-based model for each of the objects, a step of modifying the computer-based model such that for the geometric description of the plurality of objects a location is defined as a common coordinate origin, wherein the common coordinate origin is assigned to a specific location specified in build area coordinates on the build area, and wherein the respective coordinate origin of each of the objects in component coordinates is assigned to the build area coordinates of a grid point in the build area, and / or wherein the specified location is a location on the building base or a location having a fixedly predetermined position relative to the building base, a step of generating control commands for a set of control commands of the additive layer-wise building device for controlling the production of the plurality of objects by means of the additive layer-wise building device on the basis of the modified computer-based model, such that the set of control commands for each layer to be solidified during the manufacture of the plurality of objects contains data that defines the exact parameters for solidifying the building material.

3. Method according to claim 2, wherein in the step of modifying the computer-based model the computer-based model is additionally converted into a modified computer-based model by a rotation and / or central dilation with respect to a common transformation reference point for the plurality of objects.

4. Method according to claim 3, wherein a semi-finished part (120) is arranged on the building base, which semi-finished part is completed by producing the plurality of objects on said semi-finished part and wherein a common transformation reference point for the plurality of objects and the semi-finished part is taken as the basis for the rotation and / or central dilation.

5. Method according to claim 3 or 4, wherein the transformation reference point is a geometric center in the computer-based model, in particular a symmetry point or a center of gravity.

6. Method according to one of claims 3 to 5, wherein the transformation reference point is selected such that it coincides with the specified location.

7. Method according to one of claims 3 to 6, wherein it is checked whether there are overlaps of objects or overlaps of their bounding volumes in the modified computer-based model and if this is the case, the respective objects are relocated in the model until there is no longer an overlap.

8. Method according to one of claims 2 to 7, wherein a semi-finished part (120) is arranged on the building base which semi-finished part is completed by producing the plurality of objects on said semi-finished part (120), wherein the same location is selected as a reference location that was selected as a reference location in a previous building process for the semi-finished part.

9. Method according to one of the preceding claims, wherein the method runs fully automatically, that is without a necessary input from a user.

10. Device according to claim 1, wherein the model modification unit (102) is configured to additionally transfer the computer-based model into a modified computer-based model by a rotation and / or central dilation with respect to a common transformation reference point for the plurality of objects.

11. A method for producing a plurality of three-dimensional objects by means of an additive layer-wise building device that is controlled by a set of control commands which comprises control commands provided by a method according to one of claims 2 to 8, wherein in the additive layer-wise building device, the plurality of objects (3) is produced layer by layer by solidifying a shapeless building material (15) at positions corresponding to the cross-section of an object in a layer by supplying energy radiation or a binder at these positions, the method comprising at least the following steps: an application step of providing a layer of a shapeless building material (15) on a building base (11, 12) or on an already existing layer of the building material, a solidification step of solidifying the applied layer, in which step the energy radiation or the binder acts upon positions to be solidified in the layer in a build area of the additive layer-wise building device in such a way that the building material is present as a solid body after said action of the radiation or binder, wherein the application step and the solidification step are repeated successively until all cross-sections of the at least one three-dimensional object to be produced are solidified.

12. Method according to claim 11, wherein the building base is removed together with the produced plurality of objects from the layer-wise building device after completion of the production process and is introduced into a further processing device for further processing of at least one, preferably all, of the produced plurality of objects, in which further processing device the building base serves as a processing base for supporting the objects to be further treated during further processing and wherein the reference location and / or the modified model of the objects to be further processed, in which model a location is defined as a common reference location, in particular as a common coordinate origin, for the geometric description of the objects to be further processed, is conveyed to the further processing device.

13. An additive layer-wise building device for producing, layer by layer, a plurality of three-dimensional objects from a shapeless building material by solidifying the building material at positions corresponding to the cross-section of an object in a layer by supplying energy radiation or a binder at these locations in a build area of the additive layer-wise building device, wherein the device comprises: a building base (11, 12) for supporting the object (3) to be formed; an application device (14, 16) for applying a layer of the building material to the surface of the building base (11, 12) or an already existing layer, a solidification device (20) which emits energy radiation or ejects a binder and is capable of supplying the energy radiation or the binder to all positions to be solidified in a layer in such a way that the building material is present as a solid body at these positions after the action of the energy radiation or the binder, and a control device (29) which controls the application device (14, 16) and the solidification device (20) in such a way that an application step and a solidification step are repeated successively until all the cross-sections of the at least one three-dimensional object to be produced are solidified, wherein the control device (29) is configured such that it executes a method according to one of claims 2 to 9 and / or a method according to claim 11 or 12.

14. A computer program, which computer program can be loaded into a programmable control device and / or a data processing device, which computer program comprises program code means for executing all steps of a method according to one of claims 2 to 9 and / or of a method according to claim 11 or 12 when the computer program is executed on the control device and / or on the data processing device.