Method and device for generating irradiation control data for a device for additive manufacturing of a component

Abstract

The invention relates to a method for generating irradiation control data (BS) for a device (1) for additive manufacturing of a component (2) in a manufacturing process, in which the component (2) is constructed in layers in a construction field (8) by selectively solidifying the construction material (13) by irradiation of the construction material (13) using at least one energy beam (22), the method comprising the steps of: - providing a component data set (TD) comprising geometry data of at least one component layer of the component (2) and / or comprising a trajectory data set (TD) with scan track segments (B) for producing a component layer of the component (2), - creating a number of standardised target tracks (T2) from the component data set (TD), a standardised target track (T2) being formed from standard track segments (nB), the spatial length of which is an integer multiple of a standard length (N), which is determined from a predefined scan control cycle of the device (1), - generating irradiation control data (BS) in such a way that the device (1) for additive manufacturing can create a component layer with a solidification of construction material (13) on the basis of this irradiation control data (BS) along the number of standardised target tracks (T2), - outputting the irradiation control data (BS) to a memory unit and / or to a device (1) for additive manufacturing of a component (2). The invention furthermore relates to corresponding control data, a method for additive manufacturing, a control data generation device, a control unit and a manufacturing device.

Description

[0001] Method and device for generating irradiation control data for a device for additive manufacturing of a component

[0002] The invention relates to a method and a device ("control data generation device") for generating irradiation control data for a device for the additive manufacturing of a component in a manufacturing process in which the component is built up in a build field in the form of component layers by selectively solidifying build material by irradiating the build material with at least one energy beam. The invention further relates to corresponding control data, a method for the additive manufacturing of a component with such control data, a device for additive manufacturing, and a control device for such a device.

[0003] Additive manufacturing processes are becoming increasingly relevant in the production of prototypes and, more recently, in series production. In general, "additive manufacturing processes" refers to manufacturing processes in which a finished product ("component") is built up by depositing material (the "build material"), usually based on digital 3D design data. The build-up is usually, but not necessarily, layered. The term "3D printing" is often used as a synonym for additive manufacturing. The production of models, samples, and prototypes using additive manufacturing processes is often referred to as "rapid prototyping," the production of tools as "rapid tooling," and the flexible production of series components as "rapid manufacturing."As mentioned at the beginning, a key aspect is the selective solidification of the build-up material. In many manufacturing processes, this solidification can be achieved by irradiation with radiant energy, e.g., electromagnetic radiation, in particular light and / or thermal radiation, but possibly also with particle radiation such as electron beams. Examples of processes that use irradiation are "selective laser sintering" or "selective laser melting." In this process, thin layers of a build-up material, usually in powder form, are repeatedly applied one on top of the other. In each layer, the build-up material is selectively solidified by spatially limited irradiation of the areas that are to become part of the component after production, in a "welding process." The powder grains of the build-up material are partially or completely melted using the energy locally introduced by the radiation at that location.During cooling, these powder grains then solidify into a solid. Typically, the energy beam is guided across the build area along solidification paths, and the remelting or solidification of the material in the respective layer occurs in the form of "weld paths" or "weld beads," so that ultimately, the component contains a multitude of such layers formed from weld paths. In this way, components with very high quality and fracture strength can now be manufactured.

[0004] In practical applications and in manufacturing equipment, energy beams, such as laser beams, are typically used, which exhibit essentially rotationally symmetric intensity distributions. Such a rotationally symmetric intensity distribution often corresponds to a Gaussian profile. With a Gaussian intensity distribution, the intensity is highest in the center of the energy beam and decreases radially outward in all directions perpendicular to the propagation direction (also referred to as the "beam direction" or "beam axis" for short) according to a Gaussian function or Gaussian curve.

[0005] The energy beam is guided across the build area according to irradiation control data. Typically, both the movement of the energy beam and its intensity are specified by the irradiation control data. In a simple case, the control signal for the intensity can only specify when the energy beam is switched on and when it is switched off; however, intensity control or pulsed operation of the energy beam can also be implemented. The control data is usually determined directly from the geometric data of a component or its component layer, particularly through triangulation. Scan vectors are determined along which the energy beam is to be moved. Very often, a large number of scan vectors describe a path (“target path”). Starting from the target path, this is usually a polygonal line composed of individual path segments, the scan vectors.However, the problem of path segments that are too short often occurs, which leads to undesirable results, especially in pulsed operation.

[0006] For example, the triangulation of components with heavily structured surfaces leads to heavily bent target trajectories with correspondingly short distances between the bends. However, since control units operate with a fixed control clock, e.g., 100 kHz (i.e., steps of 10 ps each), this leads to the situation that for paths traversed by the energy beam in a shorter time, either a waiting time must be introduced, causing the activated energy beam to remain in one place for a correspondingly longer time, or a reduction in speed must be implemented, resulting in a longer exposure time and thus a higher energy input. This leads to local overheating, which has a negative impact on component quality.

[0007] In practice, it is often the case that the actual scan speed applied is automatically adjusted to the length of the scan vector within a control clock cycle. This results in a lower scan speed than actually desired for short scan vectors. However, since the specifications for the power of the energy beam are based on a desired scan speed, in this case too much energy is applied to the short scan vector during production. With a control clock cycle of 100 kHz (period duration 10 ps), five times as much energy would be applied to a scan vector whose length could be traversed at the desired scan speed in 2 ps. When triangulating a circle, it can very easily happen that all the vectors in the circle are quite short, e.g. 5 ps "long". In this case, twice the desired amount of energy would be applied to this desired circular path.

[0008] It is an object of the present invention to provide a method and a device for generating control data for a device for additive manufacturing of a component, which overcomes the disadvantages of the prior art and in particular allows an improvement in the quality of a component.

[0009] This object is achieved by a method according to patent claim 1, control data according to patent claim 10, a manufacturing method for additive manufacturing according to patent claim 11, a control data generating device according to patent claim 12, a control device according to patent claim 13 and a device according to patent claim 14.

[0010] A method according to the invention serves to generate irradiation control data for a device for the additive manufacturing of a component in a manufacturing process in which the component is built up layer by layer in a build field by selectively solidifying build material by irradiating the build material with at least one energy beam. The build material is preferably a liquid, a powder, or granules. Preferred materials are resin, polymer, a metal-based powder with a metal content of preferably at least 50%, in particular at least 60%, 70%, 80%, 90%, or even 90%, or a metal powder, a ceramic or mixed materials (e.g., Alumide, a product of the applicant), materials for cold metal fusion (a brand name for a combined melting / sintering process using polymer-coated metal particles as build material), or polymer-coated particles in general.

[0011] The method according to the invention comprises the following steps:

[0012] - Providing a component data set comprising geometry data of at least one component layer of the component and / or comprising a trajectory data set with scan path segments for producing a component layer of the component,

[0013] - generating a number of standardized target paths from the component data set, whereby a standardized target path is formed from standard path segments whose spatial length is an integer multiple (i.e. N times with the positive integer N greater than zero) of a standard length determined from a predetermined scan control clock of the device,

[0014] - generating irradiation control data such that the additive manufacturing device can produce a component layer with a solidification of build-up material along the number of standardized target paths using these irradiation control data,

[0015] - Outputting the irradiation control data to a storage device and / or to a device for additive manufacturing of a component.

[0016] A component data set is generally known to those skilled in the art and comprises the geometric data ("geometry data") of the component or at least one component layer of the component. This can be, for example, CAD data or data converted from CAD data.

[0017] However, a component can also be defined by predefined control data. The control data relevant here are the target trajectory data (“trajectory dataset”). Such a dataset includes at least scan path segments (scan vectors) for producing a component layer, but can also include additional exposure data, such as information about the intensity or pulse pattern used for irradiation.

[0018] This part dataset is provisioned, which means that it is received, loaded from a memory, or created from CAD data or other geometric data of the part.

[0019] The component data set therefore already includes a predefined target path, or sufficient information is available with which a target path can be determined. The method according to the invention then creates a special target path or modifies a given target path. This special target path is referred to here as a "standardized target path," which is composed of path segments, a portion of which is (specifically) formed from standard path segments. These standard path segments are not arbitrary path segments (referred to here as "scan path segments"); rather, specific rules apply to the length of these path segments. How precisely a target path is created from a component data set is state of the art and is regularly implemented in practice when converting component data sets into control commands.

[0020] Standard path segments have a spatial length that is an integer multiple (single, double, triple, ..., N times) of a standard length. This standard length is always determined from a predetermined scan control clock of the device and possibly also from other parameters, in particular the scan speed. The term "scan control clock" corresponds in particular to the control clock of the prior art and determines at least the clocking of a control of the energy beam with at least one energy beam parameter value as well as the clocking of the operation of a scanner (e.g. a galvanometer scanner and / or a polygon scanner) with at least one position specification, e.g. in the form of a 2D coordinate. If, for example, the scan speed v is given for the area of ​​a desired path, the standard length N = vt results from the scan control clock with the period t.Since the invention relates to the generation of control data, the "scanning speed" used here is a theoretical speed, as intended to be used in subsequent production, and not an actual scanning speed during production. To emphasize this, it is referred to below as the "target scanning speed." It can certainly differ from the "production scanning speed," i.e., the speed at which production proceeds. However, the production scanning speed is influenced by the control data. With the method according to the invention, the production scanning speed can be significantly optimized based on a target scanning speed.

[0021] In practice, the scan control clock can actually depend on several components, such as the control unit, beam guide and other electronic and mechanical components. Ultimately, the action specified for this time period must also be carried out within a clock cycle. For better understanding, however, it can be assumed that the control unit alone specifies the clock cycle and that the production device completes all actions on time. In practice, the scan control clock is often a fixed parameter of the control unit. In this case, the scan control clock is therefore a predefined clock cycle at whose time intervals control information is transferred and processed. This is done, for example, by specifying a point and a radiation power at each time interval, and moving to the predefined point while irradiating with the predefined radiation power.Paths to more distant points are thus less intensely irradiated than paths to closer points, since the beam must move faster to reach the specified end point. The inventive method solves this problem by adapting the distances between the points to the specified scan control clock.

[0022] It should be noted that in the case where the length of standard path segments is n times the standard length, the corresponding standard path segments are also traversed within n scan control cycles. For example, a standard path segment with the standard length is traversed within a single scan control cycle, while a standard path segment with three times the standard length is traversed within three scan control cycles.

[0023] It is not necessary for the entire standardized target path to consist of standard path segments, nor necessarily the majority of them. For example, in the area of ​​sharp curves or corners, or to compensate for remaining lengths, it may be advantageous to choose other (shorter) path segments. On the other hand, a target path that just happens to include a number of standard path segments cannot be called a standardized target path, as they have not been deliberately inserted there. For a standardized target path, it is precisely necessary that standard path segments have been deliberately inserted. This can be recognized, for example, by the fact that there is a sequence of two, three or more standard path segments, or by the fact that at least a sharp curve or corner of the target path is directly followed by a number of standard path segments.

[0024] A standardized target trajectory preferably contains more than 10% standard trajectory segments, preferably more than 30% or 50%, in particular more than 70% or 80%, or preferably at least a quarter or in particular more than half. Particularly preferably, two, three or more standard trajectory segments follow one another in a standardized target trajectory, whereby these do not necessarily all have to be the same length, but can have integer multiples of the standard length. The generation of irradiation control data is known in the prior art and is regularly carried out when converting component data sets into control commands in such a way that an additive manufacturing device can use this irradiation control data to produce a component layer with solidification of build-up material. The special feature, however, is that not (only) conventional target trajectories are included in the irradiation control data, but (also) standardized target trajectories.The irradiation control data can include only standardized target trajectories, or both standardized target trajectories and (conventional) target trajectories. However, at least one standardized target trajectory must always be included in the irradiation control data, preferably a large number of these standardized target trajectories.

[0025] The output of irradiation control data is known in the art. These can initially be output to a storage device (and stored there) for later use and / or transferred (directly) to a device for additive manufacturing of a component.

[0026] As already indicated, in a manufacturing process, build-up material is built up layer by layer in a build area, i.e., successively in several material application levels or material layers. The build-up material is preferably a metal powder or at least a metal-based powder. Such a powder preferably contains more than 50% metal, in particular more than 60%, 70%, 80%, or even more than 90% metal. However, the invention is not limited to this, but can also be used with other, preferably powdered, build-up materials, such as plastics or ceramics or mixtures of the various materials.In this process, build-up material is solidified (particularly selectively), particularly between the application of two material layers, by irradiating the build-up material with at least one energy beam generated by an irradiation unit of the production device (this refers to an energetic beam of photons or particles, e.g., a light beam or an electron beam). Not only is the build-up material in the uppermost, freshly applied material layer captured and melted or remelted by the energy beam, but the energy beam typically penetrates a little deeper into the material bed and also reaches underlying, already remelted material from previously applied material layers.

[0027] The method described above can be used to generate irradiation control data according to the invention that serves to control a device for additive manufacturing. As stated, this irradiation control data is characterized in that it comprises standardized target trajectories or is at least partially based on them. The irradiation control data also preferably comprise further design instructions such as the layer application of build material and, in particular, the lowering of the build platform between the production of the component layers. This is implicit in an arrangement of two component layers, since a new component layer on an already solidified area can only be created by applying new build material. This application generally makes it necessary to lower the build platform.

[0028] It should be noted that the invention can be applied to an entire component layer. However, its particular advantages lie where (continuous) non-rectilinear paths are present. This is particularly the case in the area of ​​(outer or inner) contours of a component layer, in the area of ​​onion-shaped paths, or in the area of ​​spiral paths. Especially with long, non-rectilinear target paths, the invention offers the advantage of a very homogeneous energy input during production.

[0029] In a manufacturing method according to the invention for the additive manufacturing of a component, the component is built up layer by layer in a build area in the form of component layers by selectively solidifying build material, preferably comprising a metal-based powder, by irradiating the build material with at least one energy beam according to the control data according to the invention. To create component layers of the component, the energy beam is guided at least partially along standardized target paths according to the irradiation control data. Because these standardized target paths have standard path segments, a correct energy input is ensured during production, at least in these areas.

[0030] A control data generation device according to the invention serves to generate irradiation control data according to the invention (according to the method according to the invention) for a device for the additive manufacturing of a component in a manufacturing process in which the component is built up in a construction field in the form of component layers by selective solidification of build material, preferably comprising a metal-based powder, by irradiating the build material with at least one energy beam.

[0031] The control data generation device comprises the following components: - a data interface designed to receive a component data set comprising geometry data of at least one component layer of the component and / or comprising a trajectory data set with scan path segments for producing a component layer of the component,

[0032] - a standardization unit designed to generate a number of standardized target paths from the component data set, wherein a standardized target path is formed from standard path segments whose spatial length is an integer multiple of a standard length determined from a predetermined scan control clock of the device,

[0033] - a control data generation unit designed to generate irradiation control data such that the device for additive manufacturing can produce a component layer with a solidification of build-up material along the number of standardized target paths using these irradiation control data,

[0034] - a data interface designed to output the irradiation control data to a storage device and / or to a device for additive manufacturing of a component.

[0035] A control device according to the invention serves a device for the additive manufacturing of a component in a manufacturing process in which the component is built up in a build field in the form of component layers layer by layer by selectively solidifying build material, preferably comprising a metal-based powder, by irradiating the build material with at least one energy beam using an irradiation device. The control device is designed to control the device for the additive manufacturing of the component layers of the component according to irradiation control data according to the invention. The control device according to the invention preferably comprises a control data generation device according to the invention.

[0036] A device according to the invention (“manufacturing device”) serves for the additive manufacturing of at least one component in an additive manufacturing process. It comprises at least

[0037] - a feeding device for applying layers of build material to a build area in a process chamber,

[0038] - an irradiation device for selectively solidifying build-up material by irradiation with at least one energy beam, in particular between the application of two material layers, and

[0039] - a control device according to the invention. It should be noted at this point that the device according to the invention can also comprise multiple irradiation devices, which are then controlled in a coordinated manner using the control data, as mentioned above. It should also be mentioned again that the energy beam can also consist of several superimposed energy beams, or that the energy beam can be either particle radiation or electromagnetic radiation, such as light or, preferably, laser radiation.

[0040] The invention can be implemented in particular in the form of a computer unit, in particular in a control device, with suitable software. This refers in particular to the creation of the control data, since the production of a component takes place using additional components. For this purpose, the computer unit can, for example, have one or more cooperating microprocessors or the like. In particular, it can be implemented in the form of suitable software program components in the computer unit. A largely software-based implementation has the advantage that even computer units already used previously, in particular in control devices of production apparatus, can be easily retrofitted by means of a software or firmware update in order to operate in the manner according to the invention.In this respect, the object is also achieved by a corresponding computer program product with a computer program that can be loaded directly into a memory device of a computer unit, with program sections for executing all steps of the method according to the invention (at least those related to the generation of control data, but possibly also those that serve to transmit the control data for a production process) when the program is executed in the computer unit. Such a computer program product can, in addition to the computer program, optionally comprise additional components such as documentation and / or additional components, including hardware components such as hardware keys (dongles, etc.) for using the software.A computer-readable medium, for example a memory stick, a hard disk or another portable or permanently installed data storage device, on which the program sections of the computer program that can be read and executed by a computer unit are stored, can be used for transport to the computer unit and / or for storage on or in the computer unit.

[0041] Further, particularly advantageous embodiments and developments of the invention emerge from the dependent claims and the following description, wherein the independent claims of one claim category can also be developed analogously to the dependent claims and embodiments of another claim category and, in particular, individual features of different embodiments or variants can be combined to form new embodiments or variants.

[0042] In a preferred method, the standard length is determined by calculating a path that can be covered within the duration of an interval of a scan control clock at a predetermined target scan speed. The step of determining the standard length is preferably carried out in a step prior to the manufacturing process. For example, it can be carried out as part of the development of process parameter value sets for specific materials and / or reference component geometries. It is preferred that the standard length N is the distance that can be covered during the duration of an interval of the scan control clock T (a frequency in Hz) at a predetermined scan speed v of an energy beam, with N = v / T.The specified (target) scanning speed can be a speed averaged from a speed curve to which an energy beam is to be accelerated or according to which an energy beam is actually accelerated if a certain distance and a time for covering this distance are specified for a certain scanner (energy beam deflection device).

[0043] It is preferred that the target scanning speed is specified as a function of a desired energy input and / or a desired pulse frequency of the energy beam and / or a geometry of the component and / or a quality criterion and / or a user specification.

[0044] It should be noted that the target scan speed can vary within a target path or between two regions of the component layer. For a target path, e.g., in the form of a polygon, standard path segments with different target scan speeds can be determined. However, a standard length is always derived from a target scan speed, so that the same standard length applies within a region of a target path that is to be traversed at the same target scan speed.

[0045] An improvement in the process, particularly for the production of geometrically complex components with a comparatively high scanning speed, can also be achieved by selecting the target speed based on a measure of geometric complexity. A measure of the complexity of an area of ​​the component layer can, for example, be a value corresponding to a fractal dimension, whereby a minimum value for the scaling is assumed to be greater than zero. In addition, a deviance can be specified by user input or a default setting, which indicates how large manufacturing tolerances can be. Since the standard length depends primarily on the target scanning speed, a standardized target path can be designed so that a shorter standard length (lower target speed) is used in areas of high geometric complexity than in regular areas.By specifying the deviation, however, the target speed can be set higher overall, since, for example, finer details of the component can also be worked out during post-processing. It is therefore particularly preferable to specify a maximum geometric deviation of the manufacturing accuracy, at least for regions of a component and / or a component layer, and to select a maximum possible target scanning speed within this deviation.

[0046] With regard to power, it is preferred within the scope of the invention that the final result achieves the most homogeneous irradiation of the component layer possible. For this purpose, the frequency of the energy beam and / or the absorption capacity of the construction material, as well as the target scanning speed or the angle of incidence or the intensity distribution of the energy beam, can also be taken into account. The term "intensity distribution" encompasses the geometric shape or extent of the energy beam in a sectional plane (cross-sectional area) perpendicular to the beam direction or beam axis, as well as the spatial distribution of the intensity across the cross-sectional area, i.e., in particular, the positions of maxima and minima.

[0047] With regard to the quality criterion, it should be noted that different materials can produce components of varying quality when subjected to the same irradiation. The desired strength of the component or dimensional accuracy represents a preferred quality criterion.

[0048] As far as a user specification is concerned, all of the aforementioned parameters cannot necessarily be specified by default, but rather by user specifications. However, the user specification preferably includes a specification as to which of the aforementioned parameters should be taken into account when calculating the standard length. In a preferred method, the component data set comprises a trajectory data set, which (in turn) comprises a number of original nominal paths, wherein an original nominal path (exactly one or at least one) is formed from scan path segments, and the standardized nominal path is created by modifying the original nominal path by replacing a majority of its scan path segments with standard path segments. Thus, nominal paths (with non-standardized path segments) already exist, and the path segments of these nominal paths are replaced by standard path segments during the modification.This can result in path deviations, which are however tolerated. However, the standard path segment used should always be the one (with an integer multiple of the standard length) which results in the smallest deviation from the original target path at that particular point. For example, if there is a target path with curves and the modification starts at the beginning of the original target path, the scan path segments of the original target path are replaced by a chain of standard path segments. When the first curve of the original target path is reached, it is determined which standard path segment (with an integer multiple of the standard length) would result in the smallest deviation from the original target path, and this standard path segment is used. The next standard path segment is then preferably selected and oriented so that the smallest deviation from the original target path occurs.In particular, long straight sections of the original target path can be approximated with a wave pattern of standard path segments if the length of this straight section does not correspond to an integer multiple of the standard length.

[0049] It is preferred to examine whether the original target path contains scan path segments whose length is less than a predetermined limit (e.g., the standard length or an integer multiple of the standard length). These scan path segments are then replaced by standard path segments. Alternatively or additionally, starting from a predetermined point on the original target path (e.g., from the beginning or from a curve or corner), scan path segments of the original target path, in particular a chain of scan path segments, are replaced by a chain of standard path segments.

[0050] It is generally preferred that standard path segments are present at least at the beginning of the standardized target path and / or after corners or curves. Chains of multiple standard path segments are particularly preferred. In a preferred method, the component data set comprises geometric data of at least one component layer of the component. A number of standardized target paths are then determined from the geometric data so that the component layer can be constructed at least partially from standard path segments. This represents an alternative to the aforementioned modification of an original target path, in which (standardized) target paths are determined directly from the component's geometric data. The general procedure is basically known in the prior art and is used to generate the aforementioned original target paths.However, the special feature in the sense of the invention is that no longer (only) arbitrary track segments may be used, but at least some of the track segments must be standard track segments.

[0051] It may also be the case that the component dataset contains some (original) nominal paths. These can then be modified, and standardized nominal paths can be created directly in the other areas. Thus, both of the above alternatives can be applied in different areas of a component layer.

[0052] In a preferred method, a target path is determined by path points. The path segments (standard and scan path segments) then preferably correspond to straight paths between consecutive path points, but could also correspond to curvilinear path segments such as circular arc segments or splines. Within the scope of a modification of an original target path (as explained above), this is approximated by a standardized target path (comprising standard path segments). Alternatively or additionally (in other areas of the component layer), within the scope of creating a standardized target path from geometric data, a structure of the relevant component layer is at least partially approximated from standard path segments.

[0053] It is preferred that a target path (the original and / or the standardized one) be a polygon. This target path was generated, in particular, by triangulating a computer-generated geometry of the component and subsequent slicing.

[0054] The general generation of target trajectories is known in the prior art. The surface of a component is represented by one or more surface segments (patches) that are mathematically described. In the simplest case, a surface segment can be a triangle or polygon, but it can also be a freeform surface or implicit surface (a mathematical surface in Euclidean space described by an equation of the form F(x,y,z) = 0). The intersection curves with the exposure plane are determined for the surface segments. If this is difficult or not possible analytically, an approximation (e.g., as a polygon) of these intersection curves can also be determined. What is not known in the prior art is that this approximation is carried out using standard trajectory segments.If the component surface encloses a volume (which does not always have to be the case), the intersection curves of a composite closed component surface are sorted in their order and concatenated to create a closed curve, i.e. intersection curves from neighboring surface segments are concatenated again. To take the width of a melt path into account, the target path in the exposure plane can be offset in the direction of the normal of the target path (which is perpendicular to the target path in the exposure plane) as part of a "beam offset". This step can be carried out with the intersection curves before the approximation, which means that the standard length can be taken into account in the approximation. Alternatively, this step can be carried out with the already approximated path segments, in which case the standardization only takes place after the offset has been calculated, since the offset changes the length of the path segments.

[0055] Additional steps can, of course, be performed. If an original target path is modified, it is stored in such a way that it can be scanned by the energy beam to produce the component. When working with geometry data, ready-made slices can be loaded, or the standardized target paths can be generated directly from CAD data. The path is then often "offset" because, due to the width of the energy beam, it should not run directly along an edge, for example.

[0056] In a preferred method, a number of path points of an original desired path or a number of points in geometric data are predetermined as a corresponding number of path fixed points. These path fixed points are points at which the standardized desired path should run. There should therefore be no deviation from the original desired path there, or the standardized desired path should lie at least at one path fixed point on the original desired path. The standard path segments are arranged in the standardized desired path in such a way that they touch the number of path fixed points and, in particular, originate and / or end there. In a preferred method, an included angle that is less than a predetermined limit angle or a curve is present whose curve radius is less than a certain limit radius.In this case, it is preferred that the course of the standardized target path be formed with scan path segments whose length differs from an integer multiple of the standard length and, in particular, is shorter than the standard length. Therefore, no standard path segments are used.

[0057] In a preferred method, the course of a standardized target path is determined as a function of a specified path width of a hardening path solidified along this standardized target path during the production of the component layer in question. The path width of a hardening path that would arise on such a target path is therefore determined in advance. This basically only requires specialist knowledge (or an experiment) of what a hardening path would look like that would arise with the specified target scanning speed and beam intensity (possibly also pulse mode). With this knowledge, it is then very easy to determine, for example, the position the (standardized) target paths should have. The distance between two adjacent standardized target paths is preferably substantially smaller than the path width, and the distance between a standardized target path and the edge of the component layer is preferably less than or equal to half the path width.The term “essentially” means that it should apply to at least 60% of the respective route, in particular to at least 80%.

[0058] It is preferred that, when modifying an original target path (see above), if it runs along the edge of the component layer, standard path segments, which replace scan path segments of this original target path, run between the original target path and the edge or on the original target path. Thus, there should be no material missing at the edge; at most, there should be an excess of material there, since subsequent removal of material is easier than subsequent addition.

[0059] In a preferred method, in addition to the component data set, additional irradiation control data is provided, which includes data on which areas of the path segments the device's energy beam is switched on and off or used in pulsed mode, and / or the desired energy beam power. In a preferred modification of scan path segments, the additional irradiation control data are then preferably additionally (appropriately) modified. This means, in particular, that the passages where the energy beam is switched on are adapted to the corresponding standard path segments.

[0060] This embodiment allows for optimization of the component production since, particularly when the desired power of the energy beam is known, it is also known which areas of the component layer should be irradiated as homogeneously as possible. Although the method according to the invention generally ensures homogeneous irradiation through the use of standard path segments, it can certainly happen that the standard length of standard path segments changes, e.g. in areas where a different target scanning speed is used for production reasons. In particular, it should be noted that there can be known changes to the target scanning speed that depend on the production device, such as braking before sharp curves or corners to compensate for scanner drag. An advantageous addition to the method according to the invention which enables particularly homogeneous production is described below.

[0061] According to a preferred method, the power of the energy beam is controlled depending on the respective length of the path segments, so that the power of the energy beam is greater for longer path segments than for shorter path segments. Since the longer path segments are often traversed during production at a higher actual production scan speed than the shorter ones and thus different amounts of energy would be introduced per area per unit time with identical power, this step allows for a more homogeneous energy introduction onto the component surface. The exact type of power control can be determined by calculations or tests. Preferably, the power of the energy beam is controlled such that the same amount of energy is introduced into the build material on all relevant path segments during production.Of course, different regions with different desired energy inputs can be selected within a component layer. The above considerations then apply within such a region.

[0062] The invention will be explained in more detail below with reference to exemplary embodiments in the accompanying figures. In the various figures, identical components are provided with identical reference numerals. They show:

[0063] Figure 1 is a schematic, partially sectioned view of an embodiment of an apparatus for additive manufacturing, Figure 2 is a block diagram of a possible process sequence of an embodiment of a method according to the invention,

[0064] Figure 3 shows an example of an original target path according to the state of the art,

[0065] Figure 4 shows an example of a standardized target path generated by the method according to the invention,

[0066] Figure 5 shows an example of a standardized target path at the edge of a component layer,

[0067] Figure 6 shows an example of a standardized target path with a fixed path point,

[0068] Figure 7 Examples of standardized target paths created by modifying an original target path.

[0069] The following exemplary embodiments are described with reference to a device 1 for the additive manufacturing of components in the form of a selective laser sintering or laser melting device. It should be explicitly noted that the invention is not limited to selective laser sintering or laser melting devices. The device will therefore be referred to below—without limiting its generality—as "manufacturing device" 1.

[0070] Such a manufacturing device 1 is shown schematically in Figure 1. The device has a process chamber 3 or a process space 3 with a chamber wall 4, in which the manufacturing process essentially takes place. Located within the process chamber 3 is an upwardly open container 5 with a container wall 6. The upper opening of the container 5 forms the current working plane 7. The area of ​​this working plane 7 lying within the opening of the container 5 can be used to build the object 2 and is therefore referred to as the construction field 8.

[0071] The container 5 has a base plate 11 which is movable in a vertical direction V and is arranged on a carrier 10. This base plate 11 closes off the container 5 at the bottom and thus forms its base. The base plate 11 can be formed integrally with the carrier 10, but it can also be a plate formed separately from the carrier 10 and fastened to the carrier 10 or simply mounted thereon. Depending on the type of specific construction material, for example the powder used, and the manufacturing process, a construction platform 12 can be attached to the base plate 11 as a construction base on which the object 2 is built. In principle, however, the object 2 can also be built on the base plate 11 itself, which then forms the construction base.

[0072] The basic construction of object 2 occurs by first applying a layer of build material 13 to the build platform 12. Then, as explained later, the build material 13 is selectively solidified using a laser beam 22 as an energy beam at the points that are to form parts of the object 2 to be manufactured. Then, with the aid of the carrier 10, the base plate 11, thus the build platform 12, is lowered, and a new layer of build material 13 is applied and selectively solidified, etc. In Figure 1, the object 2 constructed in the container on the build platform 12 is shown below the work plane 7 in an intermediate state. It already has several solidified layers, surrounded by unsolidified build material 13.Various materials can be used as the building material 13, preferably powder, in particular metal powder, plastic powder, ceramic powder, sand, filled or mixed powders or also pasty materials and optionally a mixture of several materials.

[0073] Fresh build material 15 is located in a storage container 14 of the production device 1. With the aid of a coater 16 movable in a horizontal direction H, the build material can be applied in the form of a thin layer in the working plane 7 or within the build area 8.

[0074] Optionally, an additional radiant heater 17 is located in the process chamber 3. This can be used to heat the applied build material 13, so that the irradiation device used for selective solidification does not have to introduce too much energy. This means, for example, that with the help of the radiant heater 17, a certain amount of basic energy can be introduced into the build material 13, which is naturally still below the energy required for the build material 13 to melt or sinter. An infrared radiator or VCSEL radiator, for example, can be used as the radiant heater 17.

[0075] For selective solidification, the production device 1 has an irradiation device 20, or more specifically, an exposure device 20 with a laser 21. This laser 21 generates a laser beam 22, which is deflected by a deflection device 23 in order to traverse the exposure paths or tracks (hatch lines / scan vectors) provided according to the exposure strategy in the respective layer to be selectively solidified and to selectively introduce the energy. Furthermore, this laser beam 22 is appropriately focused onto the working plane 7 by a focusing device 24. The irradiation device 20 is preferably located outside the process chamber 3, and the laser beam 22 is guided into the process chamber 3 via a coupling window 25 mounted on the top side of the process chamber 3 in the chamber wall 4.

[0076] The irradiation device 20 can, for example, comprise not just one but several lasers. These can preferably be gas or solid-state lasers or any other type of laser, such as laser diodes, in particular VCSELs (Vertical Cavity Surface Emitting Lasers) or VECSELs (Vertical External Cavity Surface Emitting Lasers), or a row of these lasers. Very particularly preferably, one or more unpolarized single-mode lasers, e.g., a 3 kW fiber laser with a wavelength of 1070 nm, can be used within the scope of the invention.

[0077] A control device 30 comprising a control unit 29 is used to control the units of the production device 1, which controls the components of the irradiation device 20, namely here the laser 21, the deflection device 23 and the focusing device 24, and for this purpose transmits process control data PS to them.

[0078] The control unit 29 also controls the radiant heater 17 by means of suitable heating control data HS, the coater 16 by means of coating control data ST and the movement of the carrier 10 by means of carrier control data TS and thus controls the layer thickness.

[0079] The control device 30 is coupled, here, for example, via a bus 60 or another data connection, to a terminal 40 with a display or the like. Via this terminal 40, an operator can control the control device 30 and thus the entire laser sintering device 1, e.g., by transmitting process control data PS.

[0080] To optimize the production process, the control data PS is generated or modified in the manner according to the invention by means of a control data generation device 34 such that the control of the device 1 takes place at least temporarily in a mode according to the invention. The control data generation device 34 here comprises a data interface 35 designed to receive a component data set TD. This component data set TD here comprises geometry data of the component layers of the component 2 or a trajectory data set TD, as shown in the following figures, with scan path segments B for producing a component layer of the component 2.

[0081] In addition to the data interface 35, the control data generation device 34 comprises a standardization unit 36, designed to generate a number of standardized target trajectories T2 from the component data set TD, e.g., by modifying trajectory data sets TD, as shown in the following figures. A standardized target trajectory T2 is formed from standard trajectory segments nB, whose spatial length is an integer multiple of a standard length N, which in turn is determined from a predetermined scan control clock of the device 1.

[0082] Furthermore, the control data generating device 34 comprises a control data generating unit 37 which is designed to generate irradiation control data BS which are part of the process control data PS.

[0083] The aforementioned data interface 35 is additionally designed to output the irradiation control data BS to the device 1 for the additive manufacturing of a component 2. However, a separate data interface can also be used for this purpose.

[0084] It is also possible for the control data generation device 34 to be implemented on an external computer unit, for example, the terminal 40, and to generate process control data PS with correspondingly matching irradiation control data BS in advance, with which the device 1 is then controlled. These process control data PS, or irradiation control data BS, can then be stored in a memory of the computer unit until their use.

[0085] It should also be noted again at this point that the present invention is not limited to such a manufacturing device 1. It can be applied to other methods for the generative or additive production of a three-dimensional object by layer-by-layer application and selective solidification of a building material, wherein an energy beam is emitted onto the building material to be solidified. Accordingly, the irradiation device can be not only a laser, as described here, but any device could be used with which energy can be selectively applied to or into the building material as wave or particle radiation. For example, another light source, an electron beam, etc., could be used instead of a laser.

[0086] Even though only a single object 2 or component 2 is shown in Figure 1, it is possible and generally common practice to produce multiple objects in parallel in the process chamber 3 or container 5. For this purpose, the build material is scanned layer by layer by the energy beam 22 at locations that correspond to the cross-sections of the objects in the respective layer.

[0087] Figure 2 shows a block diagram of a possible method sequence of an embodiment of a method according to the invention for generating irradiation control data BS for a device 1 for the additive manufacturing of a component 2 in a manufacturing process in which the component 2 is built up layer by layer in a construction field 8 by selective solidification of building material 13 by irradiation of the building material 13 with at least one energy beam 22.

[0088] In step I, a component data set TD is provided, which comprises geometric data of at least one component layer of the component 2 and / or comprises a trajectory data set TD with scan path segments B for producing a component layer of the component 2. This is symbolized here by a trajectory data set TD with an original target path T1.

[0089] In step II, standardized target paths T2 are generated from the component data set TD, here by modifying original target paths T1. A standardized target path T2 is formed from standard path segments nB, whose spatial length is an integer multiple of a standard length N, which is determined from a predetermined scan control clock of device 1.

[0090] The standard length N can, for example, be defined in such a way that a target scanning speed v1, v2 (see, for example, Figure 7) is first determined, e.g. as a function of a process window for processing a specific build material and / or a maximum scanner dynamics and / or a productivity criterion and / or a manufacturing quality criterion, and the distance is calculated that an energy beam would travel if it were guided over a build field 8 at this scanning speed v1, v2 over the duration of a scan control cycle (or an integer multiple of scan control cycles).

[0091] In step III, irradiation control data BS is generated in such a way that a production device 1, as shown in Figure 1, for example, can use this irradiation control data BS to produce component layers with a solidification of build-up material 13 along the number of standardized target paths T2. It can now be examined, for example, whether there are scan path segments B in the original target path T1 whose length is less than the standard length or an integer multiple of this standard length. These scan path segments B are then replaced by standard path segments nB. However, it is better if, starting from a predetermined point on the original target path T1, a chain of scan path segments B of the original target path T1 is replaced by a chain of standard path segments nB, as shown in the following figures.

[0092] In step IV, these irradiation control data BS are then output to a storage device and / or to a manufacturing device 1.

[0093] Figure 3 shows an example of an original target path T1 according to the prior art, which is determined by path points and whose scan path segments B correspond to straight paths between consecutive path points. Traversing these scan path segments B, which have different lengths, takes an individual time for each scan path segment B, which is indicated here.

[0094] Figure 4 shows an example of a standardized target path T2, which was created as part of a modification of the original target path T1 from Figure 3, which is still indicated here by dotted lines. This standardized target path T2 has standard path segments nB, all of which have a standard length N and whose traversal requires a fixed time specified by the scan control clock. As can be seen, the standardized target path T2 only approximates the original target path T1 and does not lie exactly on the original target path T1 at all points (arrows).

[0095] Figure 5 shows an example of a standardized target path T2 at the edge R of a component layer. In contrast to Figure 4, where standard path segments nB are located above and below the original target path T1, standard path segments nB are now always arranged toward the edge if the standardized target path T1 deviates from the original target path T1. The reason for this is that while the edge of the component can be easily reworked by removing material, adding material is more difficult.

[0096] Figure 6 shows an example of a standardized target path T2 with a fixed path point F. This fixed path point F was already defined on the original target path T1 and represents a point at which a path segment B, nB, is to end. For the standardized target path T2, no standard path segment nB is used, but rather a shorter scan path segment B to reach this fixed path point F. The path then continues from this fixed path point F with standard path segments nB.

[0097] Figure 7 shows examples of standardized target trajectories T2 created by modifying an original target trajectory T1. Two possible standardized target trajectories T2 are shown at the top and bottom right corners, which can result at different scanning speeds V1 and V2. At the top, the scanning speed v1 is higher, and at the bottom, the scanning speed v2 is lower, resulting in larger standard lengths N. Depending on the different standard lengths N, the course of the original target trajectory T1 is also approximated differently.

[0098] Finally, it should be noted once again that the devices described in detail above are merely exemplary embodiments that can be modified in a variety of ways by those skilled in the art without departing from the scope of the invention. For example, solidification could be carried out using other energy beams instead of laser light. Furthermore, the use of the indefinite articles "a" or "an" does not exclude the possibility that the respective features may be present in multiple locations. Likewise, the term "unit" does not exclude the possibility that it consists of several interacting subcomponents, which may also be spatially distributed. The expression "a number" is to be understood as "at least one." List of Reference Symbols

[0099] 1 device for additive manufacturing / laser sintering device

[0100] 2 Component / Object

[0101] 3 Process room / process chamber

[0102] 4 chamber wall

[0103] 5 containers

[0104] 6 Container wall

[0105] 7 Working level

[0106] 8 Construction site

[0107] 10 carriers

[0108] 11 Base plate

[0109] 12 Construction platform

[0110] 13 Construction material (in container 5)

[0111] 14 storage containers

[0112] 15 assembly material (in storage container 14)

[0113] 16 coaters

[0114] 17 Radiant heating

[0115] 20 Irradiation device / exposure device

[0116] 21 lasers

[0117] 22 Laser beam / energy beam

[0118] 23 Deflection device / scanner

[0119] 24 Focusing device

[0120] 25 coupling windows

[0121] 29 Control unit

[0122] 30 Control device

[0123] 31 Irradiation control interface

[0124] 34 Control data generating device

[0125] 35 Data interface

[0126] 36 standardization unit

[0127] 37 Control data generation unit

[0128] 40 Terminal

[0129] 60 buses

[0130] B Scan path segment nB Standard path segment

[0131] BS Irradiation control data F Path fixed point

[0132] H horizontal direction

[0133] HS heating control data

[0134] N Standard length PS Process control data / control data

[0135] R edge

[0136] SB process room sensor data set

[0137] ST coating control data

[0138] T1 original target path T2 normalized target path

[0139] TD trajectory dataset / component dataset

[0140] TS carrier tax data

[0141] V vertical direction v1 , v2 target parameters / scan speed

Claims

Patent claims 1. Method for generating irradiation control data (ICD) for a device (1) for the additive manufacturing of a component (2) in a manufacturing process in which the component (2) is built up layer by layer in a build field (8) by selective solidification of build material (13) by means of irradiation of the build material (13) with at least one energy beam (22), the method comprising the steps: - Providing a component data set (TD) comprising geometry data of at least one component layer of the component (2) and / or comprising a trajectory data set (TD) with scan path segments (B) for producing a component layer of the component (2), - Generating a number of normalized target paths (T2) from the component data set (TD), wherein a normalized target path (T2) is formed from normal path segments (nB) whose spatial length is an integer multiple of a normal length (N) determined from a predetermined scan control cycle of the device (1), - Generating irradiation control data (IRD) such that the additive manufacturing device (1) can use this irradiation control data (IRD) to produce a component layer with a solidification of build material (13) along the number of normalized target paths (T2), - Output of the irradiation control data (BS) to a storage device and / or to a device (1) for additive manufacturing of a component (2).

2. Method according to claim 1, wherein the standard length (N) is determined by calculating a path that can be traveled within the time period of an interval of a scan control cycle at a predetermined target scan speed (v1, v2), preferably wherein the target scan speed (v1, v2) - depending on a desired energy input and / or a desired pulse frequency of the energy beam (22) and / or a geometry of the component and / or a quality criterion and / or a user specification, and / or - changes within a target path (T1, T2) or between two areas of the component layer, in particular where normal path segments (nB) of a normalized target path (T2) are determined from different target scan speeds (v1, v2), and / or - is selected based on a measure of the geometric complexity of the component (2), preferably wherein a user setting or a preset specifies a deviance that indicates how large manufacturing tolerances may be and in Within the context of this deviance, a maximum possible target scan speed (v1, v2) is selected.

3. A method according to any one of the preceding claims, wherein the component data set (TD) comprises a trajectory data set (TD) which includes a number of original target paths (T1), wherein an original target path (T1) is formed from scan path segments (B), and the normalized target path (T2) is created by modifying the original target path (T1) by replacing a plurality of its scan path segments (B) with normal path segments (nB), preferably wherein it is investigated whether there are scan path segments (B) in the original target path (T1) whose length falls below a predetermined limit, and wherein the scan path segments (B) of the original target path (T1) whose length falls below the predetermined limit are replaced by normal path segments (nB) and / or wherein, starting from a predetermined point of the original target path (T1), scan path segments (B) of the original target path (T1), in particular a chain of scan path segments (B),is replaced by a chain of standard track segments (nB).

4. Method according to claim 1 or 2, wherein the component data set (TD) comprises geometry data of at least one component layer of the component (2), and a number of normalized target paths (T2) are determined from the geometry data, so that the component layer can be built up at least partially using normal path segments (nB).

5. A method according to one of the preceding claims, wherein a target path (T1, T2) is determined by path points and the path segments (B, nB) correspond to straight paths between successive path points, wherein, in the context of a modification of an original target path (T1), it is approximated by a normalized target path (T2), and / or, in the context of creating a normalized target path (T2) from geometry data, a structure of the relevant component layer is at least partially approximated from normal path segments (nB), preferably wherein a target path (T1, T2) is a polygon, and in particular was generated by triangulation of a computer-generated geometry of the component (2) and subsequent slicing.

6. Method according to claim 5, wherein a number of path points of an original target path (T1) or a number of points in geometry data is predetermined as a corresponding number of path fixed points (F) at which the normalized target path (T2) is to run, and wherein the normal path segments (nB) are arranged in the normalized target path (T2) in such a way that they touch the number of path fixed points (F) and in particular originate and / or terminate there.

7. Method according to one of the preceding claims, wherein in a path section of a target path (T1, T2) in which an included angle (W) is present which falls below a predetermined limit angle or a curve is present whose curve radius falls below a certain limit radius, the course of the normalized target path (T2) is formed with scan path segments (B) whose length differs from an integer multiple of the standard length (N) and is in particular shorter than the standard length (N), preferably wherein at least one path fixed point (F) according to claim 6 is present in this path section, in particular at a corner point or a curve.

8. A method according to one of the preceding claims, wherein the course of a normalized target path (T2) is determined as a function of a predetermined path width of a hardening path formed along this normalized target path (T2) during the production of the component layer in question, wherein the distance between two adjacent normalized target paths (T2) is substantially less than the path width and the distance of a normalized target path (T2) to the edge (R) of the component layer is less than or equal to half the path width, preferably wherein, when modifying an original target path (T1), if it runs at the edge of the component layer, normal path segments (nB), which replace scan path segments (B) of this original target path (T1), run between the original target path (T1) and the edge (R) or on the original target path (T1).

9. Method according to one of the preceding claims, wherein, in addition to the component data set (TD), further irradiation control data are provided, which include data on which areas of the path segments (B, nB) the energy beam (22) of the device (1) is switched on and off or pulsed and / or what power the energy beam should have, and preferably wherein - when modifying scan path segments (B), the other irradiation control data are also modified, and / or the power of the energy beam is controlled depending on the respective length of track segments, in particular where the power of the energy beam is greater for longer track segments than for shorter track segments.

10. Control data (PS) for controlling a device (1) for additive manufacturing, comprising irradiation control data (BS) which have been generated according to a method according to one of the preceding claims.

11. Manufacturing process for the additive manufacturing of a component (2), wherein in a build field (8) the component (2) is built up layer by layer by selective solidification of build material (13) by irradiating the build material (13) with at least one energy beam (22) according to the control data (PS) according to claim 10, wherein to create component layers of the component the energy beam (22) is moved over the build field (8) within defined areas according to the control data (PS).

12. Control data generation device (34) for generating irradiation control data (BS), in particular according to claim 10, for a device (1) for the additive manufacturing of a component (2) in a manufacturing process in which the component (2) is built up layer by layer in a build field (8) by selective solidification of build material (13) by means of irradiation of the build material (13) with at least one energy beam (22), the control data generation device (34) comprising: - a data interface (35) designed to receive a component data set (TD) comprising geometry data of at least one component layer of the component (2) and / or comprising a trajectory data set (TD) with scan path segments (B) for producing a component layer of the component (2), - a normalization unit (36) designed to generate a number of normalized target paths (T2) from the component data set (TD), wherein a normalized target path (T2) is formed from normal path segments (nB) whose spatial length is an integer multiple of a normal length (N) determined from a predetermined scan control cycle of the device (1), - a control data generation unit (37) designed to generate irradiation control data (CD) such that the additive manufacturing device (1) can use this irradiation control data (CD) to produce a component layer with a solidification of build material (13) along the number of normalized target paths (T2), a data interface (35) designed to output the irradiation control data (BS) to a storage device and / or to a device (1) for additive manufacturing of a component (2).

13. Control device (30) for a device (1) for the additive manufacturing of a component (2) in a manufacturing process in which the component (2) is built up layer by layer in a build field (8) by selective solidification of build material (13) by means of irradiation of the build material (13) with at least one energy beam (22) by means of an irradiation device (20), wherein the control device (30) is configured to control the device (1) for the additive manufacturing of the component layers of the component (2) according to control data (PS) according to claim 10, wherein the control device (30) preferably comprises a control data generation device (34) according to claim 12.

14. Device (1) for the additive manufacturing of at least one component (2) in an additive manufacturing process with at least - a feeding device for applying layers of build material (13) to a build area (8) in a process chamber (3), - an irradiation device (20) to selectively solidify build-up material (13) by irradiation with at least one energy beam (22), in particular between the application of two material layers, and - a control device (30) according to claim 13.

15. Computer program product comprising instructions which, when the program is executed by a computer, cause it to perform the steps of the method according to any one of claims 1 to 9 and / or 11.

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