EP3934833A1

EP3934833A1 - Control method, control device and production apparatus

Info

Publication number: EP3934833A1
Application number: EP20708079.7A
Authority: EP
Inventors: Andreas Hoppe; Christiane Thiel; Ann-Kathrin OTTE; Daniel Brueck; Jan Wilkes; Dieter Schwarze
Original assignee: SLM Solutions Group AG
Current assignee: Nikon SLM Solutions AG
Priority date: 2019-03-04
Filing date: 2020-03-02
Publication date: 2022-01-12
Also published as: JP7407832B2; WO2020178216A1; US20220193769A1; CN113543910A; JP2022523412A

Abstract

The invention relates to a control method for controlling a multi-beam apparatus having one or more beam sources for producing a plurality of beams of a system for manufacturing a three-dimensional workpiece by means of a generative layer construction method, in which method a material that can be solidified in order to manufacture the three-dimensional workpiece is applied in layers to a surface of a carrier and the material that can be solidified is solidified by the plurality of beams in a respective layer at points of incidence of the plurality of beams on the material that can be solidified, wherein the points of incidence of the beams for solidifying selective regions of the layers of the material that can be solidified in order to manufacture the three-dimensional workpiece are each controlled substantially against a gas flow direction of a gas flow over the surface of the carrier; wherein the control method comprises: (a) dividing the material to be solidified in the respective layer into at least two sections, wherein two of the at least two sections extend in the gas flow direction of the gas flow prevailing over the two of the at least two sections in succession at least in part, (b) dividing at least one of the two of the at least two sections into at least two surface pieces, (c) assigning each of the surface pieces to exactly one specific beam, which solidifies the material to be solidified in the assigned surface piece, (d) controlling the points of incidence of the beams such that, at at least one point in time during an exposure of the material to be solidified, the material to be solidified is solidified in at least two surface pieces, and a network consisting of straight lines extending between each center point of the points of incidence to every other center point of the points of incidence, at no point in time during the exposure, in which all center points of the points of incidence are located outside of a predetermined distance from each other, has a straight line parallel to the gas flow direction of the gas flow prevailing over the two of the at least two sections.

Description

Control method, control device and manufacturing apparatus

The invention relates to a control method for controlling a multi-beam device with one or more radiation sources for generating several beams of a system for producing a three-dimensional workpiece by means of a generative layer construction method. The invention also relates to a computer program that can be loaded into a programmable control device, with a program code to execute at least part of a control method according to the present invention when the computer program is executed on the control device. The invention also relates to a data carrier which contains the computer program. The invention also relates to a control device for

Controlling a multi-beam device having one or more radiation sources for generating a plurality of beams of a plant for the manufacture of a dreidimensiona ^¬ len workpiece by means of a generative layer construction process. It further relates to the ^¬ invention a manufacturing apparatus for manufacturing a three-dimensional

Workpiece using a generative layer construction process.

In generative method for producing three-dimensional workpieces, and in particular at generative layer manufacturing method, it is known to use a raw material powder layers on a support provided with a vertically moving means heights ^¬ is adjustable to apply and such by site-specific irradiation. B. to solidify by fusing or sintering in order to ultimately obtain a workpiece of a desired shape. The irradiation can take place by means of electromagnetic radiation, in particular laser radiation, or particle radiation. Is a workpiece layer solidifies, the height-adjustable carrier, a layer thickness is lowered vertically and applying a new layer of unprocessed raw material powder Mate ^¬ rial to the already prepared workpiece layer. To this end, be ^¬ knew Beschichteranordnungen or powder applicators can be used. Subsequently, the now topmost and still unprocessed raw material powder layer is irradiated again. As a result, the workpiece is built up successively layer by layer, with each layer defining a cross-sectional area and / or a contour of the workpiece. In this context, it is also known to use CAD or comparable workpiece data in order to produce the workpieces essentially automatically. Known devices for producing three-dimensional workpieces are described, for example, in EP 2 961 549 A1 and EP 2 878 402 A1.

Multi-jet systems are described in WO 2018/172080 A1, among others.

The object of the invention is to provide a control method which improves the scanning strategy of a multi-beam device. In particular, the invention is based on the object of providing a control method for controlling a multi-beam device with one or more radiation sources for generating multiple beams of a system for the production of a three-dimensional workpiece by means of a generative layer construction process that achieves uniform utilization of all radiation sources or optics, a collision of Plumes of smoke with rays avoids and prevents spray particles of the material to be solidified from being melted with one ^another .

This object is achieved by a control method, a control device and a manufacturing device according to the independent claims. Preferred embodiments thereof are described in the dependent claims.

The disclosed control method does not have to be used for every layer of the solidifiable material or of the component, but can also only be applied to a few (ie a predetermined number of) layers or even only to a single layer. In particular, when in the layer only (very) few and / or very small areas (ie, areas having a predetermined maximum extent) are provided to be solidified material, such as at very fi ^¬ pedigree single component sections or support members, an application of the procedural ^¬ Rens omitted. For the purposes of the invention, an application to individual layers is also understood as an application of the control method. However, the method is preferably used for all layers of the material to be consolidated or of the component.

The present disclosure describes a control method for controlling a multi-beam device with one or more radiation sources for generating multiple beams of a system for manufacturing a three-dimensional workpiece by means of a generative layer construction method, in which a solidifiable material for manufacturing the three-dimensional workpiece is applied in layers to a surface of a carrier and the solidifiable material in a respective Layer is solidified at respective points of incidence of the plurality of jets on the solidifiable material by the plurality of jets, the points of incidence of the beams for solidifying selective areas of one of the layers of solidifiable material for the production of the three-dimensional workpiece each essentially counter to a gas flow direction of a gas flow over the surface of the Vehicle controlled; wherein the control method comprises;

(a) dividing the material to be solidified in the respective layer into at least two sections, with two of the at least two sections extending at least partially one behind the other in the gas flow direction of the gas flow prevailing over the two of the at least two sections,

(b) dividing at least one of the two of the at least two sections into at least two patches,

(c) Assigning each of the patches to exactly one particular beam that solidifies the material to be consolidated in the assigned patch,

(d) controlling the reaching positions of the beams such that at least ei ^¬ nem time of exposure of the to be solidified material which is solidified to be solidified material into at least two surface sections, and a network of between each center of the impact points on each of ^¬ whose center is the impact locations extending straight at any time ^¬ point of the (current, for example during a predetermined time period) exposure, in which all the center points of the impact locations are out ^¬ half of a predetermined distance (for example of the Unbehelligungsabstandes as defined below) to each other, a straight line parallel the Gasströ ^¬ flow direction of the nant on the two of the at least two sections Vorherr ^¬ gas flow has.

The sections can have different shapes. Approximately shapes in some execution include sections columns which extend substantially perpendicular to the gas flow direction of gas flow, ie, the layer of the to verfesti ^¬ constricting material is divided in at least two columns, with the columns substantially perpendicular to the gas flow direction of the gas flow extend. The number and / or position and / or shape of the sections can be determined by the optics configuration of the machine, for example by the number and / or processing areas of the beams for solidifying the material. Alternatively or additionally, the number and / or position and / or shape of the sections can also be determined by the observation areas of one or more sensors and / or by position and / or shape and / or be influenced by a desired quality of the component geometry in the layer to be solidified or the vectors resulting therefrom, with the aid of which the rays for solidifying the material are directed over the material layer. For this purpose, for example, the angular deflection of the scanner mirrors and / or the introduced laser power and / or an acceptable influence from smoke cones and / or the position of merging regions of hatch vectors and / or an optimization of the construction time can be taken into account. Such an alignment of the gaps or sections extending essentially perpendicular to the gas flow direction of the gas flow is, however, generally not absolutely necessary, but can in principle also have free-form. It is additionally or alternatively possible that a section encloses another section and / or that a section is formed from several non-contiguous surfaces. The at least two sections are, however, determined by the fact that they at least partially undercut one another when viewed from the direction of gas flow. Through the back ^¬ Tailoring gives at least between two fields that are in respectively different sections, a relation of a field generated in terms of influencing the processing by the by the processing of the other field

Smoke cones.

The boundaries between two sections can have a certain tolerance range at ^¬. This particular can serve CKEN at a division of Flächenstü ^¬ based on a vector distribution on the component geometry micro-vectors to avoid. A piece of surface can therefore extend into another section to a certain extent (for example up to a predetermined maximum overlap length and / or up to a predetermined maximum surface size).

Within a distance referred to in this document as the clearance distance, the mutual influence of two processing beams by their

No smoke and / or splashes exceeded to a certain extent. The un ^{¬ disturbance} distance can be implemented as a general measure in the control or determined for the specific construction contract. The clearance distance can depend on the component material and / or the applied laser power (i.e. spot size and / or shape of the exposure point and / or laser power per area and / or wavelength and / or feed speed and / or angle of incidence between the beam and the powder surface) of the two laser beams and / or the desired component quality. When using multiple beams with different beam parameters ^¬ union under the Unbehelligungsabstand, for each Beam combination to be different from each other. In some embodiments, two jets may also work simultaneously in the gas flow direction, one behind the other, within this defined non-interference distance.

In this document, a further distance is defined as the discharge distance, which is relevant for the mutual influencing of the processing of two beams with respect to one another. The discharge distance is understood as the distance over which splashes produced by machining are at least transported away from the machining site by the gas flow before they descend again on the level of the construction site, i.e. before they land in the powder bed. This distance differs from the unmolested distance. While the clearance distance takes into account an influence on the smoke and spatter produced by irradiating the material to be solidified in the beam path of the processing beam, i.e. a defocusing and / or blocking of the radiation, the discharge distance takes into account the influence of the spatter that has fallen in the powder bed. This distance is on the one hand dependent on the spatter of the current machining, ie on the construction material as well as the parameters of the introduced laser Leis ^¬ device (spot size, laser power per unit area, wavelength, feed rate, angle of incidence between beam and powder surface area), and on the other hand by the flow conditions of the Place of processing prevailing gas flow. The discharge distance can be stored as a globally uniform value or defined for each machining ^beam . Furthermore, it is also possible for the discharge distance to be determined separately as a function of one or more of the parameters mentioned for each irradiation site on the material to be solidified. With optimal gas guidance in the multi-jet device, the discharge distance is infinite at all locations on the construction site, ie all splashes are carried away by the gas flow in such a way that no splashes fall on the construction site. In some embodiments, however, the discharge distance is greater than the clearance distance. Since that can adversely affect the exposure of the site and thus the component quality in areas of the construction site, which may be descended zer in gas flow direction outside the transfer distance of already processed positions potentially fuel ^¬, irradiation should there not preferred place in some embodiments. The sequence of irradiation of the material to be solidified is therefore preferably to be controlled in such a way that the impact points of the jets in the gas flow direction are always guided within a discharge distance to already processed points of the material to be solidified in the respective layer. However, the beams are particularly preferably controlled in this way It is stated that the impact points of the jets are generally only guided against the direction of gas flow to already processed points of the material to be solidified in the respective layer.

A radiation source can be used to generate several beams through optics known to those skilled in the art (e.g. beam splitters). Alternatively, a beam is generated by a respective radiation source.

The respective points of impact of the multiple beams can be different, or at least partially identical and / or overlap.

In some embodiments, the surface elements is exactly to a particular beam of each of the Fiächenstücke by its location on the surface of the support and / or to a gas flow outlet of the gas flow to one or meh ^¬ reren assigned to specific beams of the multiple beams before the assignment. Thus advantageously a certain area only by one or more beams are irradiated, de ^¬ ren incidence when striking the material to be solidified in a ^¬ be voted are angular range.

In some embodiments, the points of incidence of the rays are at least partially controlled continuously over the surface of the carrier.

In some embodiments, at least two of the center points of the impact points are located outside of the predetermined distance from one another for at least a predetermined duration. In some embodiments, there are all the means ^¬ points of impact locations for at least the predetermined duration outside of the predetermined distance to each other. This allows the layer to be efficiently irradiated in different areas.

In some embodiments, a position and / or expansion are the sections on the surface of the carrier and / or a number of sections defi ^¬ defined based on: an expansion and / or position of the three-dimensional working ^¬ tee in the layer of solidifiable material, and / or a layer of

Scan fields of the rays, which are configured via points of perpendicular incidence of rays and an extent with reference to the surface of the support and / or an angle to the axis of the respective perpendicular incidence of rays. This allows advantageous ^¬ way in particular the efficiency of production of the three-dimensional workpiece are increased and a certain area only through one or more beams are irradiated, the angle of incidence when hitting the material to be solidified are in a certain angular range.

In some embodiments, all sections are defined in the direction perpendicular to the gas flow direction of the gas flow with the same extent. Alternatively or in addition, all sections in the gas flow direction of the gas flow are defined with the same extent. This uniform distribution can increase the efficiency of the production of the three-dimensional workpiece, since in particular a uniform distribution can be guaranteed when assigning sections to certain beams.

In some embodiments, the exposure of each surface piece in a second section, which extends at least partially in front of another first section in the gas flow direction, is only started after the material to be consolidated of all surface pieces of the first section has been completely irradiated. This can advantageously ensure that the exposure of the second section has no effects on the material that was already exposed in the first section. This can increase the quality of the three-dimensional workpiece.

In some embodiments, each point of impact is controlled in such a way that it is not located in the gas flow direction outside of a discharge distance from a point at which the material to be solidified of the respective layer has already been irradiated. This ensures that splashes that occur during exposure of a certain area only end up in another area that has already been exposed. This ensures that spatter in a certain layer is not exposed. The quality of the three-dimensional workpiece can thus be increased. In some embodiments, the number of surface pieces into which the corresponding section is divided is defined based on an extension of the section perpendicular to the gas flow direction of the gas flow and / or a position of the section in the layer of the solidifiable material. For example, fewer beams can be used in narrow component areas of the three-dimensional workpiece to be produced and the corresponding section or sections can be divided into fewer beams. In some embodiments, a number of surface pieces in a section is defined by a maximum number of rays that are exposed at the same time in the section or a multiple thereof. This can increase the efficiency of the

Production of the three-dimensional workpiece can be increased, in particular since all the rays are used simultaneously to expose the material to be solidified.

In some embodiments, the patches in a section are essentially divided into patches of equal size. In some embodiments, each column is subdivided into equidistant pieces according to the number of rays or into surface pieces of the same size. In each of these pieces the vectors can be assigned to the corresponding ray. In this way, an even utilization of the beams can be achieved.

In some embodiments, the predetermined number of Flächenstü ^¬ corresponds CKEN each of the sections of a number of the multiple beams.

In some embodiments, each of the patches, which is assigned to a limited hours ^¬ th beam of the multiple beams divided into a plurality of irradiation fields ba ^¬ sierend on a beam diameter and / or the maximum deflection angle of the particular beam. Are this leads to a particularly uniform from ^¬ utilization of radiation and can, in particular in manufacturing plants with optics configurations which, for example, a widening of a beam diameter. With a zoom optics, have used.

In some embodiments, a closed contour of producing a three-dimensional contour of the workpiece regardless of the location of the Kon ^¬ turzugs is allocated in the patches to one or more beams, in particular only ei ^¬ nem beam. In particular, a closed contour train can be used

Preparation be arranged a three-dimensional contour of the workpiece to a single beam ^¬. This allows the dreidimensiona ^¬ len workpiece be secured (by any possible overlap visible) a good surface quality. Contours can be divided into separate areas, which can then be clearly different from the predominant grid. Preferably, however, contour trains can be processed independently of a grid superimposed on the construction field, ie the assignment of contour trains to a beam can take place independently of the allocation of patches of a grid to different processing beams. The patches themselves are still after a applied scan strategy assigned to the processing beams. An influence resulting from the positional relationships of the surface pieces to one another and a processing sequence resulting therefrom can, however, be maintained for the processing of the contour trains and surface pieces. For the purposes of the invention, an area whose surface area is assigned to a first processing beam without the components of contour lines and through which one or more contour lines run which are assigned to one or more further processing beams is understood to be assigned only to the first processing beam. In some embodiments, the material to be consolidated is divided into the surface pieces in the respective layer by means of a grid or a superposition of several grids. In the assignment of vectors of a layer to a scanning system ^¬ be made with regard to the construction and the component quality within the manufacturing plant for the production of the three-dimensional workpiece must be a compromise between optimization. Due to the grid or the superposition of several grids, a uniform distribution of vectors, in particular hatch vectors, over all available optics with synchronized scan progress contrary to the

Direction of gas flow and taking into account interactions with the

Schmauch can be accomplished. As an alternative or in addition, when assigning or dividing the vectors to the various beams (or

Radiation sources) the number of vectors must be taken into account. This Alloc ^¬ voltage can be selected so that the quality of the product to dreidimensiona ^¬ len object is optimized. Thus, in some embodiments, this is based

Subdividing the material of the layer to be solidified into a number and / or length of vectors which are assigned to the respective beams, the vectors defining a scanning process of the layer by the beams. Alternatively or additionally, the subdivision can also be based on an exposure time of the respective rays. In the case of a division of the vectors into processing beams and / or an allocation of surface pieces of a grid, preference can be given to

Processing beams, a position of the scan fields of the scanning systems in relation to the construction field are taken into account in such a way that the processing beams do not cross each other (or never at least for a predetermined period of time).

In some embodiments, the subdivision of the material of the layer to be solidified is based on an exposure time assigned to the respective beams, in particular essentially uniformly distributed. The overall exposure time can be reduced by increasing the efficiency of the production of the three-dimensional workpiece. In some embodiments, a first grid divides the layer into areas, each of which can be reached by single or multiple beams. The areas are configured via points of perpendicular incidence of rays and an extent with respect to the surface of the support and / or an angle to the axis of perpendicular incidence of rays.

In some embodiments, a second grid divides the material to be solidified in the respective layer according to a vector alignment of vectors (e.g. hatch vectors) of the beams (for hatch vectors in a hatch pattern based on a hatch distance and a hatch rotation of the Hatch pattern), the vectors defining a progression of the rays (on the carrier surface). Vector blocks can be retained, with (hatch) vectors not being split up and no microvectorization taking place.

In some embodiments, a region in which the vectors (for example, Hatch vectors) merge (that is, adjacent to each other in vector direction) is not divided in various ^¬ dene sections that are assigned to different beams. The ^¬ together reunification of fields can be considered. In particular, the

Vector alignment of the vectors in adjacent patches can be defined in such a way that vectors at the surface boundaries do not converge. Vectors whose respective ends point to one another and have the same xy coordinates are thus not scanned by different beams at the same time. Overheating and unwanted material evaporation can be avoided in this position and in this local area, can be so prevents Po ^¬ ren arise because of a deep welding effect. Specifically, a merging region is therefore preferably assigned to only one ray, so that simultaneous processing of two vectors that meet one another is excluded. Particularly preferred who merged ^¬ the converging vectors, so that the merging region is eliminated.

In some embodiments, the sections are designed as columns running essentially perpendicular to the gas flow direction of the gas flow, and an extension of the respective column is defined parallel to the gas flow direction of the gas flow such that each of the columns has the same number and / or the same length comprises processing vectors and / or a same computational ^¬ joint and several exposure time of the beams. The scan area distribution can be used by global ^¬ to divide the scanning progress here. In some embodiments, at least one section is divided into patches so that an equal number of beams that can be used for the material to be consolidated in each patch to expose the patch and / or a substantially equal number of vectors (e.g. hatch vectors) in each patch and / or an essentially equal sum of the length of the vectors in each area and / or an essentially equal exposure time is achieved in each area. For each patch there can be information regarding the optics or rays that can be used for exposure of the respective patch, the number of (hatch) vectors and a length of the (hat) vectors in each patch.

In some embodiments, a section is ^¬ len each of Strah in at least the one surface element has been assigned in the section of at least an equal number and / or total length of vectors (for example, Hatch vectors) and / or a moving ^¬ che exposure time and / or assigned an equal number of patches. In this way, a uniform scan progress and / or an optimization (in the best case an approximately uniform distribution) of the scan time can be guaranteed.

At lattice structures in some embodiments, the marking time division-total and / or the total mark length and / or the Ge ^¬ can be made velvet Markieranzahl based on the.

In some embodiments, the control method further comprises determining, based on an irradiating the solidifying material in the layer in egg ^¬ nem first face piece with one of the beams, a range with respect to the surface of the carrier, in which an occurrence of Schmauch and / or splashes caused by the irradiation in the first patch is expected, and a determination, based on the area in which the occurrence of smoke and / or the splash is expected, whether a second patch by the jet or one other beam can be irradiated. Thus, the duration for the manufacture ^¬ can development of the three-dimensional workpiece can be reduced, while ensuring that a beam does not collide with the Schmauch or no spatter, which was caused by a first beam that is melted by another beam.

It is easy to see that, within the meaning of the invention, not the entire control ^{method is performed} on a control device integrated in a multi-beam device must be carried out, but can also only partially be carried out on this. In particular, it is possible that parts of the control method can be carried out, for example, at a conventional PC workstation. The resulting instructions for the multi-beam device can then be transferred to the multi-beam device, for example by means of a network connection or a data carrier.

In some embodiments, the beams comprise laser beams, in particular all beams being laser beams. In particular, the one or more radiation sources comprise lasers. In particular, all laser beams have an essentially identical wavelength and / or an essentially identical power and / or an identical, in particular punctiform, shape of the point of impact. In some embodiments, the beams comprise at least two laser beams which have a different wavelength and / or a different power and / or a different shape of the point of impact.

The laser beams can be the same or different, i. for example, at least two laser beams can have a different wavelength and / or a different power and / or a different irradiation surface and / or a different geometry of the irradiation surface. The differences can be achieved by different beam-shaping optics in the beam path of the respective beams and / or at least individual beam properties can be achieved by different laser beam sources, for example solid-state lasers (disk, rod or fiber lasers), diode lasers or gas lasers can be used.

Furthermore, a computer program is described, which can be loaded into a programmable control device, with a program code in order to carry out at least part (e.g. completely) of a control method according to the present description when the computer program is executed on the control device.

The present disclosure further comprises a data carrier that contains the computer program, the data carrier comprising an electrical signal, an optical signal, a radio signal or a computer-readable storage medium. The present disclosure further comprises a control device for controlling a multi-beam device with one or more radiation sources for generating multiple beams of a system for manufacturing a three-dimensional workpiece by means of a generative layer construction method, the control device comprising: one or more processors; and a memory containing instructions executable by the one or more processors, whereby the control device is operable to at least control the points of incidence of the beams according to d) (see above) (or completely) the method according to that described herein Execute embodiments.

Further, the present disclosure includes a manufacturing apparatus for the manufacture ^¬ position a three-dimensional workpiece by means of a generative layer manufacturing method ^¬, said manufacturing apparatus comprising: a multi-beam device having one or more radiation sources for generating a plurality of beams; and the control device according to the embodiments described herein.

If a radiation source is used, the multiple beams can be generated by optics known to those skilled in the art, e.g. Beam splitter, are generated.

Because of their location relation to each other, the terms building field, applies the surface can be solidified or synonymously ver to be solidified material, layer of material, component or device layer, and carrier powder bed with respect to a subdivision ^¬. It is easy to understand that a division of one of the things mentioned causes an analogous division of the other. So when we talk about the construction field, this also means the material layer located in the construction field or its surface, or the component to be built there.

The invention will in the following with reference to the accompanying diagrammatic figures nä ^¬ forth explained, of which

Figure 1 is a schematic sketch of a scan strategy for scanning a

Layer for producing a three-dimensional workpiece using egg ^¬ nes generative layer construction method shows

FIG. 2 shows a schematic sketch of a further scanning strategy for scanning a layer for the production of a three-dimensional workpiece with the aid of a generative layer construction method, Figure 3 shows schematic sketches of component geometries,

FIG. 4 shows a schematic sketch of a positional relationship between the construction field and scan fields of an exemplary optical configuration,

Figure 5 shows a schematic sketch of an exemplary division of a carrier plate,

FIG. 6 shows a schematic sketch of a further exemplary division of a

Carrier plate shows

FIG. 7 shows a schematic sketch of a further scanning strategy,

Figure 8 shows a schematic sketch of a further scanning strategy,

Figure 9 shows a schematic sketch of a subdivision of a layer,

FIG. 10 shows a schematic sketch of a subdivision of a layer according to FIG

9 shows

Figure 11 shows a schematic sketch of a further subdivision of a layer,

Figure 12 shows a schematic sketch of a smoke cone and its relationship to a subdivision of a layer;

FIG. 13 shows a schematic sketch of a further scanning strategy,

FIG. 14 shows a flow diagram of a control method,

Figure 15 shows a schematic diagram of a manufacturing apparatus,

FIG. 16 is a schematic sketch of an interaction of a laser with a

Shows smoke trail from another laser outside of a safe distance, FIG. 17 shows a schematic sketch of an interaction of a laser with a

Shows smoke plume from another laser within a safe distance,

Figure 18 shows a schematic sketch of a further subdivision of a layer,

Figure 19 shows a schematic sketch of a further subdivision of a layer,

FIG. 20 shows a schematic sketch of a further subdivision of a layer,

Figure 21 is a schematic diagram showing a subdivision of a layer with a radially ^¬ from the center of the construction field outwardly extending Gasströ mung, and

FIG. 22 shows a schematic sketch of a processing point with the clearance distance and discharge distance resulting from the position.

The present invention relates in particular to a scanning strategy for a multi-beam device, in particular for a multi-laser selective laser melting machine.

The embodiments described here achieve that a smoke plume of a processing spot does not get into another beam (e.g. laser beam) (or ^vice versa, that is, that a beam (e.g. laser beam) is not steered into a smoke plume that is generated by another beam) .

In some embodiments the machine comprises e.g. 7, 12, 15 or more lasers, any other number of lasers can be used.

Some embodiments consist of a strategy of how these scan vectors can be divided between the various optics (eg laser beams) of a multi-beam machine (eg multi-laser machine). The description of lasers or laser sources in the present disclosure relate equally to other radiation sources, such as, for example, particle sources (for example electron beam sources). All embodiments disclosed in the present description are therefore not necessarily restricted to lasers or laser sources.

Objectives of dividing the scan vectors on different optics are under at ^¬ alia a uniform utilization of all lasers as well as prevention of colli ^¬ sion of plumes with laser beams and prevent meltdown of spray particles (based on an exposure to gas flow), the waiting times between Irradiation of different areas can arise. A minimum and maximum distance between the beams can be achieved by the embodiments described. In some embodiments, different exposure times, despite an equal number of vectors per beam, it aims ^¬ x so that after the processing of a column of the width and the length y, which is detected by the beam, to wait for a signal that the last Vek ^¬ tor was exposed in this column. Only then, in some examples, is the exposure of the next column continued. Thereby, the Maximalab ^¬ is stood defined between adjacent beams, and it may be necessary that the vectors in the form of a column divided into a data register written ^¬ the.

When assigning vectors of a slice to a scanning system within e.g. In a Selective Laser Melting system, a compromise must be made between optimization in terms of construction time and in terms of component quality.

The embodiments described herein allow a time and qua ^¬ formality optimized division of scan vectors to different scanning systems in a selective laser melting plant. In some embodiments, a superposition of different grids is used for this purpose in order to divide a layer into fields, which can then be assigned to an optical system based on the idea of uniform distribution over all optics. At the same time, however, a uniform progress against the direction of gas flow can be guaranteed. This gives the possibility of optimizing the time in the case of manufacturing processes that are not ideally distributed by bringing forward areas closer to the inflow of the gas, whereby the quality of the workpiece is not negatively influenced (in particular by taking into account smoke cones). For the contours of the workpiece to be produced, a quality-optimized allocation of areas of the layer to be consolidated and the optics is sought. Here, for example, the optics areas can be limited based on the surfaces in order to be able to optimize the quality of the workpiece in these areas with regard to the deflection angle of the beam of the respective optics. Alternatively or additionally, closed contours can be assigned as few optics as possible. For this purpose, it is possible to assign the contour trains to the machining beams independently of the division of the sections and areas, and to use the area division only to determine the processing sequence of the areas and contours. This ensures a good surface quality (if possible, no visible overlap).

A speed-optimized allocation is sought for the hatches, taking into account the uniform scan progress of all optics against the gas flow direction and avoiding interactions between smoke cones of an optics and areas still to be exposed.

FIG. 1 shows a schematic sketch 100 of a scanning strategy for scanning a layer for the production of a three-dimensional workpiece using a generative layer construction method.

The sketch shows a lying in the building plane construction field 102, a component 104, laser spots ^¬ 106, a smoke cone 108, the direction of the gas flow 110 as well as the Rich ^¬ processing 112 in which proceeds the processing.

A machine configuration is assumed here, as an example, in which seven laser beams or exposure points 106 can be directed onto the construction field 102 by means of seven scanner optics, each scanner optics being able to be directed onto every point of the construction field 102, i.e. the scan fields of the scanner optics completely overlap.

The exposure points, here laser spots 106, are controlled such that they are always arranged approximately in a line which is perpendicular to the direction of gas flow in the construction plane (x, y).

The processing proceeds from left to right, ie against the gas flow. As shown in FIG. 1, the component layer (or, in the case of several components, the construction field) is subdivided in the x-direction into a suitable number of columns or sections (in this example numbered from columns 1-13). The columns do not necessarily have to be straight, but can, for example, be bounded along checkerboard fields (vector blocks), which can be rotated by an angle to the columns shown.

In addition, a minimum distance and / or a maximum distance between two laser spots may be defined in the algorithm, so that if narrow part areas as shown in Figure 1 in the right part of the component, not all (in this example, 7) laser for a coming ^¬ set, but the sections only on a smaller number of lasers (e.g. 5 lasers) can be split up. This may be advantageous in order to have excessive ^¬ A flow of syringes to avoid the adjacent laser and a local overheating ^¬ wetting through the use of multiple lasers in a narrow location area to prevent.

Each column is divided into equidistant patches according to the number of lasers. As equidistant patches large area pieces are here equal verstan ^¬. In each of these patches, the vectors are assigned to the corresponding laser.

The column width can, for example, be selected in advance as a fixed value or also be selected as a function of an existing hatch pattern, which is present, for example, as fields with hatch vectors. In particular, the column width can be selected such that the columns are divided into fields (according to the number of beam sources) whose number of vectors and / or their vector length and / or their exposure time is approximately evenly distributed. Furthermore, the column width can also be selected as a function of a minimum and / or maximum distance between two laser spots.

This scanning strategy allows a very simple breakdown of the device layer, regardless of the component geometry and also to calculate with low computing capacity in health ^¬ space of time. Due to the column-wise processing, the

Influencing a laser spot 104 of another La ^¬ serspots effectively prevented by a smoke cone 108th However, depending on the component geometry, more processing time is required compared to other strategies. FIG. 2 shows an example of a further scanning strategy 200 in which the gas flow direction of the gas flow 110 and the direction 202 of the processing sequence of the checkerboard fields are shown for each of the lasers. A machine configuration is assumed here, for example, in which twelve laser beams can be directed onto the construction field 102 by means of twelve scanner optics, each scanner optics being able to be directed onto a line of the construction field 102 extending in the processing direction 202 over the entire width of the construction field 102. The extension of the line perpendicular to the processing direction 202 is designed such that the scan fields of the scanner optics at least partially overlap.

By assigning the patches to the corresponding lasers according to the checkerboard pattern, a uniform utilization of the lasers is achieved. Advertising For this purpose, the number of the device layer in a line perpendicular to the machining Rich ^¬ tung 202 patches located by the number of in this range scan fields of the scanner optics, ie divided by the number of possible to use laser beams, and allocated to the laser beams. FIG. 3 shows a schematic sketch of component geometries 300. The gas flow direction of the gas flow 110 and the direction 302 of the exposure against the gas flow are shown.

The assumed machine configuration can include, for example, fifteen or more scanner optics, each scanner optics being able to be aimed at a line of the construction field 102 extending in the machining direction 302 over the entire width of the construction field 102. The extension of the line perpendicular to the machining direction ^¬ 202 is executed so that the scan fields of the scanner optics overlap at least partially. Alternatively, however, so many beams can also be provided that the laser spots only have to be guided over the construction field with a parallel advance in the machining direction 302; for this purpose, several beams can also be directed by means of a common optical system. In addition, the laser spots do not necessarily have to have a round geometry, but can also have an oval, rectangular or polygonal geometry, for example. The one or more optics do not necessarily have to be scanner optics; it can also be one or more movable processing optics. In this example, the laser spots are always arranged approximately in a row perpendicular to the direction of gas flow.

The points in the sketch in FIG. 3 thus represent the laser spots or fusible bands at different times in the machining direction 302.

The strategy also works accordingly if a large number of components are arranged on the platform.

Figure 4 shows a schematic diagram of the relationships of an exemplary optical configuration with seven scanner optics for building field 102. The points 401-407 zei ^¬ gene, the positions of the laser beams at a normal beam incidence on the building area 102 of the respective scanner optics, ie the so-called optical center points. The field 411 represents the scan field of the optics belonging to the point 401, the field 416 represents the scan field of the optics belonging to the point 406. The scan fields of the optics belonging to the points 402-405 are not shown for reasons of clarity, but are shown in FIG Size analogous to fields 411 and 416. The scan field of the optics belonging to point 407 covers the entire construction field 102.

Figure 5 shows a schematic sketch of an exemplary partitioning 500 of the Baufel ^¬, ie, a carrier plate or of the layer of material to be solidified, which is applied to the carrier surface, for a machine having an optical configuration according to FIG. 4

The basic idea here is that the production platform is completely divided in this example into three global column 511-513, which lobe portions by the over ^¬ result of the scan fields of optics configuration. Each column is in the ^¬ sem Example then divided into a plurality of rows. Each row is then assigned a specific optic. In this example, the first column 511 and the third column 513 are divided into four rows, and the second column 512 is divided into ^seven rows, based on the number of optics that reach the respective column.

In this example, the positions of the row and column borders firmly held ^¬ be th. A change occurs in columns in the machine direction 502 against the gas flow. Editing of the following column will not begin until the current column has been completely edited. One advantage of this scanning strategy is that it is easy to implement. The problems that are based on the resulting smoke / smoke cone and syringes can be solved by this scanning strategy. Vector blocks can be defined accordingly in a scan file.

In this scanning strategy, some optics are not used in some examples, while others are used at the same time to solidify the material of the layer.

With this scan strategy a division of the slice is possible. The processing direction opposite to the gas flow direction can be taken into account here.

FIG. 6 shows a schematic sketch of a further scan strategy 600 which is based on the division from FIG.

In this scanning strategy, an optimal position of the boundary of a row is calculated for each column based on an optimization of a hatch distribution. In particular, an approximately uniform distribution of the number and / or length of the hatch vectors can be aimed for. The position of the boundaries of the row is no longer fixed in this example, individual rows can be made wider than other rows. In the figure, this is shown in the third main column 513, in which the two inner rows are significantly narrower than the outer ones because, for example, a component geometry (not shown) in the third main column 513 of the component layer to be processed is limited to an area in the middle of the column is. The production speed of the workpiece can thus be optimized.

In this example, each of the three main columns 511-513 is subdivided into additional sub-columns in accordance with FIG. The processing of a following column only begins when all rows contained in the column have been processed. This can improve the behavior with regard to the smoke cone and the splashes. A laser beam leading in a row is not so far possible that it can be impaired by its smoke cone. By the column size ^¬ a defined maximum distance between two adjacent laser spots is strictly adhered to. For this purpose, for example, a column width equal to the maximum distance can be selected. In order to prevent microvectors, a segment reaching into an adjacent grid cell may be allowed. The minimum cell size is defined here and depends on the width of a column or the chessboard patch (maximum length of a hatch vector).

The columns are irradiated in a synchronized manner. All rows in a column can e.g. be irradiated simultaneously. The irradiation of the next column is started when the previous column has been irradiated by all optics or scanners. The problems that can be caused by smoke cones or splashes generated by a forward laser beam are thereby solved or

circumvented, whereby the production time of the workpiece may be extended by additional waiting times.

Figure 6 also shows that the row boundaries in the third main column 513 are shifted more towards the center because e.g. the component to be generated has more area to be generated in the third main column than in the edge area. In principle, a change in the row distribution can be permitted not only when the main column changes, but also from sub-column to sub-column. The sub-columns can in particular also be viewed as sections themselves.

FIG. 7 shows a schematic sketch of a further scan strategy 700.

In order to improve the production rate or production speed, in this exemplary scan strategy all cells are irradiated in a row one after the other and independently of cells in the same column. However, to better solve the problems that may be caused by the smoke cone or splashes, it is checked for each cell whether radiation that cell is not blocked by other len Zel ^¬. This leads to an increased production rate, wherein the ^pre-¬ called problems are solved or taken into account.

In this example, the irradiation of the cell 702 is potentially blocked by the cells 704, since an irradiation of the cell 702 would result in a smoke cone, which would negatively affect the component quality if the cells 704 were simultaneously irradiated. The definition of which cells would be negatively influenced by the smoke cone when irradiated at the same time depends on parameters such as the component material, the laser power applied (i.e. spot size, laser power per area, deflection speed) and the desired component quality. Cell 702 can therefore not be irradiated before the component geometries to be built located in the cells 704 have been irradiated.

FIG. 8 shows a schematic sketch of a further scan strategy 800.

In this exemplary scan strategy, the grid is further defined.

In the example scan strategies described above, the grid was aligned with the axes. Depending on the grid size, this can result in many separate vector blocks.

In the scan strategy 800, the grid is not aligned to the axes, but a cell grid 810 is used which is aligned to a hatch pattern, the ^¬ sen fields 820 in the example are rotated by 45 ° to the axes and the hatch vector gates 825 include. This results in fewer decompositions for the same

Grid size and fewer cells are defined overall, which increases the construction output for manufacturing the workpiece.

In some embodiments, the grid forms a right angle with the direction of the hatch segments, or divides the construction field into right-angled fields 820.

Through this scanning strategy, the space better used for vector blocks ^¬ because fewer partitions are defined to.

In some embodiments, the scan field is divided in such a way that a multigrid aligned with the hatch rotation is used for uniform distribution of hatch vectors over all available optics with a synchronized scan progress against the gas flow direction 110 and taking into account interactions with the smoke. In Figure 8, the arrows show 801 to 807 hen seven Optikrei ^¬, the machining directions ie seven side by side working machining rays.

The grid in Figure 8 is selected so that the fields is 820 - nition at a Spaltendefi ^¬, each having a field in each of the optical rows per column contains 801-807 - from the perspective of the gas flow direction 110 undercut. If all the processing beams are directed onto the construction field at the same time, it can happen that two beams work simultaneously one behind the other in the gas flow direction. This can be accepted with a sufficiently small distance from one another, without a serious deterioration in the component quality, see comments on FIG. 17. The maximum distance up to which the mutual influence does not exceed a certain amount is referred to herein as the clearance distance. The clearance distance can depend on the

Component material and / or the applied laser power (i.e. spot size, laser power per area, deflection speed) of the two laser beams and / or the desired component quality. When using several beams with different beam parameters, the clearance distance for each beam combination can be different from one another. Since two jets are allowed to work one behind the other in the gas flow direction at this defined distance from interference, two points of incidence of the jets that are within an unobstructed distance from one another are used to check the curve relationship that a curve laid through the points of incidence does not have a tangent at any time runs parallel to the direction of gas flow, treated as a point with the position of its center.

FIG. 9 shows a schematic sketch of a subdivision of a layer or of the construction field.

A grid 900 is defined here, taking into account the maximum achievable areas of the respective optics according to the optics configuration from FIG. 4 via the point of perpendicular incidence of a beam and its extent in the x and y directions.

In this example, fields are displayed Errei ^¬ sponding optics including their allocation of this field.

Figure 10 shows a schematic sketch of a ^¬ build on the grid of Figure 9 the further sub-division of a layer, or of the construction field 102nd

The grid 1000 is based on a superimposition of the grid of FIG. 9 with a further grid that is defined according to the vector alignment with dynamic consideration of the hatch rotation per slice. The grid results from the hatch distance and the hatch rotation.

Vector blocks are retained. Hatch vectors are not split and microvectorization does not take place. Here, combined hatch vectors can be displayed undivided, taking into account a combination of fields.

A correction of the vector direction in the case of merged hatch vector blocks can be carried out in some embodiments. Vectors with their respective ends pointing towards each other and having the same xy coordinates are not scanned by different beams at the same time. Overheating and unwanted material evaporation can be avoided in this position and in this local area, can be so prevents pores are formed due to a deep silence ^¬ ßeffekts.

The fields generated in the grid 1000 are overlaid with the areas from FIG. 9, each of which can be reached by certain optics.

In some embodiments, if the field is completely within the coverage area of an optic, a field can potentially be assigned to that optic.

The allocation of the fields to the optics then occurs as a function of the distribution of the component geometry, the actual hatch arrangement in the building field 102, as well as possibly further parameters which influence the part quality and / or the processing time be ^¬ ie. A further division into columns and / or rows can also take place in accordance with one of the strategies described above.

FIG. 11 shows a schematic sketch of a further subdivision of a layer or of the construction field 102.

In this example, the grid 1100 defines columns perpendicular to the gas flow direction with variable widths, so that there is as even a number and length of hatch vectors as possible in each column, which can be evenly distributed over all optics. This can be approximated using areas in order to save the calculation time for this.

This leads to a use of the global scan area distribution to classify the scan progress.

The grid 1100 is thus based on columns with a uniform scanning area per optic. In this example, a minimum number of columns is defined, which results from a minimum width of the columns. In this example, the minimum width of a column results from the hatch length and the hatch rotation.

In this example, the gaps are processed against the direction of gas flow 110.

In this example, the column boundaries do not necessarily have to be straight lines perpendicular to the gas flow direction, but can also be free-form.

To generate the grid 1100 in FIG. 11, for example, the grid 1000 from FIG. 10 can be assumed; for this purpose, the grid 1000 is applied to the component structures 104 to be generated in the building plane. The division into columns then takes place in accordance with a uniform distribution of the vector lengths, exposure times and / o ^¬ the exposure area on the scanner optics. Based on the respective

The column boundary and the point of intersection of the grid 1100 in FIG. 11 with the grid 1000 in FIG. 10 result in field boundaries corresponding to the hatch rotation.

Are for each field in this example, the following information: (i) Useful Op ^¬ tiken for scanning of the corresponding field; (ii) number of hatch vectors in the field; (iii) Length of hatch vectors in the field.

In the herein described examples, the assignment is made of individual fields to ei ^¬ ner optics under the basic idea that each optical system in a column (see grid 1100) an equal amount as possible (ie, number) and / or length at Hatch Vector Design ^¬ ren assigned gets to ensure that the scan progresses evenly.

If due to the component geometry, uneven distribution (test eg based on grid in 1000) can not be avoided, that is, when getting a mandatory assigned a shorter exposure time or meh ^¬ eral optics in a column as one or more other optics can be tested beyond, whether areas from a column further to the right can be brought forward in order to save construction time, but under the premise that the smoke that is created does not interfere with the scanning of fields in the columns further to the left. An example is the device structure 1106 in column 6 of the grid in Figure 11, which part ^¬ as merely forms an undercut with the device structure in column 1 in the gas flow direction 110th If the processing beams working in the lower part of the construction field 102 could not be deflected onto the upper part these are only directed briefly at the construction field 102 while the columns 2-5 are being processed and would be switched off during the processing of the upper component structure.

FIG. 12 shows a schematic sketch of such a smoke cone. The restricted areas of a field are all fields to the left of the field that are overlaid by the smoke cone.

FIG. 13 shows a schematic sketch of a further scanning strategy.

In this example, the following fields have already been processed: field A2 through optics 1; Fields A3 and B3 through optics 2. In this example, field A6 is currently being processed by optics 4. In this example, field B6 through optics 4, field A7 through optics 5 and field E2 still to be processed the optics 2.

In this example, optical system 2 is completed, it is checked whether the next of these optics can be exposed to ^¬ child fields. The next field for optics 2 is field E2. This is "released" for exposure when the fields marked by the regions 1302 (ie the fields to the left of the regions 1302) are completed with the exposure. The definition of the regions 1302 depends on the smoke / spatter angle and can be from the defined fields or a function (x, y in the construction field).

In this example, optics 2 can begin to expose field E2 as soon as the exposure of field A6 has been completed. There is no need to wait for field B6 to be exposed.

FIG. 14 shows a flow diagram of an exemplary control method 1400.

In this example, the control method 1400 includes a step S1402 for providing ^¬ position of the scan fields of the individual processing beams in the building field, the possible processing areas that is, the beams for solidification of the to be solidified material in the respective layer in the construction field, as well as data to a gas flow rich ^¬ processing. In step S1402 the parameters of the current machine configuration are provided.

In step S1404, the component geometry is riding provided in the respective layer in the construction field be ^¬, that is, the selectively solidifying areas. In step S1406, the regions of the respective layer to be consolidated are then divided into at least two sections which extend at least partially one behind the other in the gas flow direction. The number and / or position and / or shape of the sections can be determined by the optical configuration of the machine, for example by the number and processing areas of the beams for solidifying the material. Alternatively or additionally, the number and / or position and / or shape of the sections can also be determined by the observation areas of one or more sensors and / or by the position and / or shape and / or the desired quality of the component geometry in the layer to be hardened and / or the resulting Vectors, based on which the rays to solidify the material over the

Material layer are directed, be influenced. For this purpose, for example, the angular deflection of the scanner mirror and / or the introduced laser power and / or an acceptable influence from smoke cones and / or the position of merging regions of hatch vectors and / or construction time optimization can be taken into account. The sections can be selected in such a way that the sections have a relationship of a possible negative influence without further subdivision to one another if at least two sections were processed at the same time, i.e. that if at least part of a section is processed at the same time, the processing of at least part of another section would be negatively influenced.

In step S1408, at least one section is divided into at least two patches. The classification criteria are essentially the same as for the subdivision into the sections, in particular the number of laser beams possible in the section for exposure and / or a vector distribution for controlling the beams on the material to be solidified can determine the number of surface pieces. The surface pieces are preferably chosen so that the simultaneous processing of at least two surface pieces in one section is made possible. In particular, one of the methods and strategies described above can be used to subdivide the patches. The other sections can also be divided into patches or contain only one patch. After the at least one section has been divided into at least two surface pieces, the material to be consolidated is therefore divided into at least three surface pieces in the respective layer.

In step S1410, each patch is assigned to exactly one processing beam. As described above, contours of a component to be generated can run over several surface pieces and then apply independently of the assignment, that is, in the context of the invention, they are not and cannot be considered part of the surface piece thus can also be processed by a beam other than the beam assigned to the patch. Preferably, each patch is not only assigned a processing beam, but also a processing sequence of all patches assigned to a beam is determined globally or in sections.

A method is preferably selected from the strategies described above which provides the fastest possible processing under the required framework conditions (eg component quality). In step S1412, the processing beams are controlled according to the allocation and possibly designated order, being solidified to at least one time to ver ^¬ Firming material in at least two patches, that is, wherein at least two processing beams irradiate two patches simultaneously. Individual steps of the steps S1402-S1412 may include sub-steps, except ^¬ the can before, between, and other steps are executed / or after steps S1402-S1412. In addition, the control method 1400 does not have to be used for every layer of the material to be consolidated or of the component. It is also possible to carry out individual or several steps outside of a multi-beam device, for example at a computer workstation. Only

Step S1412 to be performed by a controller of the multi-beam device through ^¬.

FIG. 15 shows a schematic diagram of a heel splitting device 2000. The production device 2000 comprises a multi-beam device 2002 with one or more radiation sources for generating a plurality of beams. The multi-beam device can also have one or more optics, for example scanner optics. The manufacturing device further comprises a control device 2004 connected to the multi-beam device for executing the control method according to the embodiments described herein. In a non-illustrated process chamber also includes the manufacturing apparatus, a material bed (here powder bed) 1506 for receiving settable material 1510, through the selective Verfesti ^¬ a component supply 104 is prepared. The surface of the material bed 1506 forms the construction field 102. A vertically adjustable carrier 1505 for receiving the material 1510 is arranged in the material bed 1506. The figure shows a point in time at which four material layers 1511-1514 are already arranged on the carrier, the topmost material layer 1514 being currently being processed. For this purpose, a first point of impact 106 'of a first laser beam 1531 and a second impact point 106 ″ of a second laser beam 1532 controlled via the construction field 102. The uppermost material layer 1514 shows different areas, a first zigzag hatched area 1521 representing solidifiable material that is not intended for solidification. A second obliquely hatched area 1522 shows this Production of the component 104 represents material to be consolidated. A third brick-shaped hatched area 1523 represents the already consolidated material. The manufacturing device 2000 can also contain sensors (not shown), for example radiation sensors such as cameras, which are assigned to the construction field 102 and / or the multi-beam device 2002 or can be contained therein and can be connected to the control device 2004. In addition, the manufacturing device 2000 has a gas supply device 1500, for example in the form of a nozzle or several nozzles, through which gas in one (possibly locally to different points n of the construction field of different) gas flow directions 110 for the removal of smoke and / or syringes produced during the processing via the processing points 106 ', 106 ".

FIGS. 16 and 17 show schematic sketches of an interaction of a laser with splashes 1601 generated by a second laser and a plume of smoke 1602. In FIG. 16, the laser 1 interacts with the plume of smoke 1602 caused by the laser 2. In this example, the distance between the two lasers in the x direction is relatively large (compared to the example shown in FIG. 17). The smoke plume is relatively strong in the z-direction. Laser beam 1 is defocused by the smoke plume. This results in a reduced energy input into the powder bed.

In FIG. 17, laser 1 also interacts with the plume of smoke caused by laser 2. In this example, the distance between the two lasers in the x direction is relatively small. The smoke plume is relatively small in the z-direction. The laser beam 1 is only weakly defocused by the smoke plume. A reduced energy input into the powder bed can be limited by a defined, maximum distance in the x-direction.

Also shown in FIGS. 16 and 17 is a discharge distance A and an unmolested distance U. FIG. 18 shows a subdivision of a construction field 102 into a first section 1810 and a second section 1820. Section 1810 extends in the direction of gas flow behind section 1820. The dividing line of the two sections runs diagonally across the construction field and is thus based on component structures 104a, 104b in the illustrated material layer. According to the invention, the processing of structure 104a will take place at least partially before structure 104b.

FIG. 19 shows a further subdivision of a construction site 102 into a first circular section 1910, a second circular section 1920 and a third section 1930 which encloses the two sections 1910 and 1920. The sections can be example chosen so because the component structure has 104 in the areas of sections 1910 and 1920 higher quality requirements, or because the Bauteilge ^¬ ometrie there for a processing may be unfavorable. According to the invention, the processing of the sections 1910 and 1920 will at least partially take place before the section 1930, if necessary the processing of the sections 1910 and 1920 can take place at least partially at the same time.

Figure 20 shows a further sectioning. A first section 2010 and a second section 2020 do not contain the entire construction field 102, but are oriented in accordance with a component structure 104. The division can be made, for example, on the basis of an even distribution of the exposure time. For the purposes of the invention, Section 2010 will be at least partially processed by Section 2020.

FIG. 21 shows a further subdivision of the material layer, or of the construction field 102, or of the component 104. In this example, one is derived from a center of the

Construction field of the radially outwardly extending gas flow direction 110 'assumed. The construction field includes a first section 2101, a second section 2102, a third section 2103 and a fourth section 2104. All other sections extend completely behind section 2101 in the gas flow direction 110 '. In addition, the fourth section 2104 extends partially behind in the gas flow direction 110' the third section 2103.

FIG. 22 shows a point of impact 106 of a first laser beam on the material layer located in the construction field 102. Around the processing point 106 results with the unmolested distance U as a radius (if one considers the processing point 106 as

Point without its own extension), or curve spacing assumes an undisturbed zone 2201 in which a second laser beam could be irradiated at the same time. A curve piece 2202 shows with the discharge distance as a radius or Curve spacing is a limit behind which no simultaneous or subsequent exposure of the first or second laser should take place in the gas flow direction.

The following examples are also covered by the present disclosure and may be included in whole or in part in embodiments of the invention described herein:

1. Control method for controlling a multi-beam device with one or more radiation sources for generating several beams for a system for manufacturing a three-dimensional workpiece by means of a generative layer construction method, the control method comprising:

Controlling the plurality of beams such that the beams are substantially ent ^¬ long a line at an impinging on a surface of a support on which a tightening by the plurality of beams to a material for producing the dreidi ^¬ dimensional workpiece is applied, are arranged, wherein the line is substantially perpendicular to a gas flow direction of a gas flow which is used to remove a Schmauchs, produced when solidifying the righting to verfes ^¬ material by the jets,

wherein the radiation for solidifying a layer of the ert are to be solidified mate rials ^¬ for producing the three-dimensional workpiece substantially opposite the gas flow direction of the gas flow over the surface of the carrier gesteu ^¬;

wherein the control method further comprises:

Dividing the layer of material to be solidified into a predetermined number of sections, each of the sections extending essentially perpendicular to the gas flow direction of the gas flow,

Subdivide each of the sections into a predetermined number of patches, each of the patches being associated with one or more particular rays of the plurality of rays that solidify the material to be consolidated in the associated patch, and wherein each of the sections is based on a predefined minimum spacing and / or maximum distance between adjacent beams at the impingement of the beams on the surface of the carrier during the solidification of the layer is divided to be solidified material to prepare the dreidi ^¬ dimensional workpiece into the surface of the pieces.

2. The control method of Example 1, wherein the predetermined number of patches into which the corresponding section is divided, based on a strain-off ^¬ the section perpendicular to the defined gas flow direction of the gas flow and wherein the expansion is based on an expansion of the three-dimensional workpiece in the layer to be solidified.

3. Control method according to example 1 or 2, wherein the patches in a section comprise equidistant patches.

4. The control method according to any one of Examples 1 to 3, wherein the predetermined number of patches of each of the sections corresponds to a number of the plurality of beams.

5. A control method according to any one of Examples 1 to 4, wherein the dividing of the layer on a plurality of vectors associated with the ^¬ based the respective beams, where the vectors define a scanning of the layer by the radiation.

6. The control method according to any one of Examples 1 to 5, wherein each of the patches associated with a particular one of the plurality of beams is divided into a plurality of irradiation fields based on a beam diameter of the particular beam.

7. The control method of Example 6, forming a closed contour for the manufacture ^¬ position is allocated to less than a ^¬ limited hours th number of the multiple beams of a three-dimensional contour of the workpiece.

8. Control method according to one of Examples 1 to 7, wherein the layer of the material to be consolidated is divided into the surface pieces by means of a grid or a superposition of several grids.

9. The control method of Example 8, wherein a first raster surface, the layer in preparation ^¬ which are maximum respectively achieved by the multiple beams splits.

10. Control method according to Example 9, wherein the regions are configured via points of perpendicular incidence of rays and an extension in the x-y direction with respect to the surface of the carrier.

11. Control method according to one of Examples 8 to 10, wherein a second grid shows the layer of the material to be consolidated according to a vector alignment of vectors of the rays, the vectors defining a progression of the rays.

12. The control method of Example 11, wherein the vectors comprise hatch vectors, and wherein the second raster shows the layer of material to be consolidated according to the vector orientation of the hatch vectors in a hatch pattern based on a hatch distance and a hatch rotation of the Hatch patterns, the hatch vectors defining the progression of the rays.

13. The control method of Example 11 or 12, wherein a region in which the vectors merge, not into different sections, the different rays zugeord ^¬ net is divided.

14. A control method according to example 13, wherein the vector orientation of the vectors is defined in the region such that successive vectors do not run in the region ^¬.

15. Control method according to one of Examples 11 to 14 when dependent on one of Examples 9 or 10, wherein the layer is divided into the patches based on the superposition of the first grid with the second grid.

16. A control method according to any one of Examples 1 to 15, wherein the sections Spal ^¬ include th that is substantially perpendicular to the gas flow direction of the gas flow extend, and wherein an extension of each column is defined parallel to the gas flow direction of gas flow in such a way that each of the Columns has the same number and / or the same length of vectors of the rays.

17. Control method according to example 16 when dependent on example 15, wherein the overlay comprises an overlay of the first and second grids with the columns.

18. Control method according to one of Examples 1 to 17, wherein the layer is subdivided based on a number of radiation sources usable for a field of the layer for scanning the field, a number of vectors in the field and a length of the vectors. 19. Control method according to one of Examples 1 to 18, wherein each of the radiation sources in one of the sections is assigned an equal number and / or length of vectors.

20. Control method according to one of Examples 1 to 19, further comprising:

Determining, based on an irradiation of the material in the layer in a first patch with one of the rays, of an area with respect to the surface of the carrier, the smoke and / or splashes that result from the irradiation in the first patch, and

Determining, based on the area of the smoke and / or the splashes, whether a second patch is caused by the jet or another jet, taking into account a position of the jet or the other jets upon impact on the layer relative to the area of the smoke and / or the splash, can be irradiated.

21. A control method according to any one of Examples 1 to 20, wherein the laser beams include ^¬ rays.

22. A computer program that can be ^loaded into a programmable control device, with a program code to carry out a control method according to one of Examples 1 to 21 when the computer program is based on the

Control device is running.

23 disk that contains the computer program according to example 22, wherein the data carrier an electrical signal, an optical signal or a radio signal compu ^¬ terlesbares storage medium comprises.

24, control means for controlling a multi-beam device having one or more radiation sources for generating a plurality of beams for a plant for the production of a three-dimensional workpiece by means of a generative layer ^¬ construction method, wherein said control means comprises:

one or more processors; and

contains a memory storing instructions that one or several ^¬ ren processors of the executable, whereby the control means is operable to perform the method of any of examples 1 to 21 to be performed. 25. Manufacturing device for manufacturing a three-dimensional workpiece by means of a generative layer construction method, the manufacturing device comprising:

a multi-beam device with one or more radiation sources for generating several beams; and

the control device according to example 24.

Claims

1. Control method for controlling a multi-beam device with one or more radiation sources for generating multiple beams of a system for the production of a three-dimensional workpiece by means of a generative layer construction process, in which a solidifiable material for the production of the three-dimensional workpiece is applied in layers to a surface of a carrier and the solidifiable material is steady in a particular layer at respective landing points of the plurality of beams on the solidifiable material through the plurality of beams ver ^¬,

wherein the points of incidence of the beams for solidifying selective areas of one of the layers of solidifiable material for producing the three-dimensional workpiece are each controlled essentially against a gas flow direction of a gas flow over the surface of the carrier;

where the tax method comprises:

(a) dividing the to solidifying material in the respective layer in at least two sections, wherein two of the at least two Caesarean section ^¬ nen in the gas flow direction of the prevailing across the two of the at least two sections of gas flow at least partially extend one behind the other

(d) controlling the points of incidence of the beams such that at at least one point in time of an exposure of the material to be solidified the material to be solidified is solidified in at least two patches, and a network of between each midpoint of the points of incidence to each other

The center of the impingement points of straight lines at no point in time of the exposure in which all center points of the impingement points are outside a predetermined distance from one another does not have a straight line parallel to the gas flow direction of the gas flow prevailing over the two of the at least two sections.

2. A control method according to claim 1, wherein the impact points of the beams to be ^¬ least partially controlled continuously over the surface of the carrier.

3. Control method according to claim 1 or 2, wherein at least two of the center points of the points of impact are outside the predetermined distance from one another for at least a predetermined duration.

4. The control method according to claim 3, wherein all center points of the impact points are outside the predetermined distance from one another for at least the predetermined duration.

5. Control method according to one of the preceding claims, wherein prior to the assignment of the surface pieces to exactly one specific beam, each of the surface pieces is assigned to one or more specific jets of the plurality of jets by its position relative to the surface of the carrier and / or to a gas flow outlet of the gas flow.

6. Control method according to one of the preceding claims, wherein a position and / or an extension of the sections on the surface of the carrier and / or a number of the sections are defined based on:

an extension and / or position of the three-dimensional workpiece in the layer of the solidifiable material, and / or

a layer of scan fields of the beams vertically above points Strah ^¬ leneinfälle and configured expansion with respect to the surface of the carrier and / or an angle to the axis of the respective vertical beam incidence.

7. Control method according to one of the preceding claims, wherein all Sekti ^¬ ones in the direction perpendicular to the gas flow direction of the gas flow with dersel ^¬ ben expansion are defined.

8. Control method according to one of the preceding claims, wherein all Sekti ^¬ ones are defined in the gas flow direction of the gas flow with the same extent.

9. Control method according to one of the preceding claims, wherein the Belich ^¬ processing of each surface element in a second section, which at least partially extends in Gasströ ^¬ flow direction in front of another first section, is only started after the to be solidified material of all patches of the ers ^¬ th section was completely irradiated.

10. Control method according to one of the preceding claims, wherein each point of impact is controlled so that it is not located in the gas flow direction outside of a discharge distance to a point at which the material to be solidified of the respective layer has already been irradiated.

11. Control method according to one of the preceding claims, wherein a number of surface pieces into which the corresponding section is divided is defined based on an extension of the section perpendicular to the gas flow direction of the gas flow and / or a position of the section in the layer of the solidifiable material.

12. Control method according to one of the preceding claims, wherein an ^¬ number of surface pieces in a section is defined by a number of the maximum number of rays exposing at the same point in time in the section or a multiple thereof.

13. Control method according to one of the preceding claims, wherein the surface elements in one of the sections are substantially tert rushes into equally sized patches un ^¬.

A control method according to any one of claims 1 to 12, wherein the dividing of the material to be consolidated of the layer is based on a number and / or length of vectors assigned to the respective rays, the vectors defining a scanning of the layer by the rays .

15. Control method according to one of claims 1 to 12, wherein the dividing of the material to be solidified layer on a the respective beam supplied ^¬ arranged, in particular substantially uniformly distributed, exposure time, is based.

16. Control method according to one of the preceding claims, wherein each of the patches that is assigned to a particular beam of the plurality of beams is divided into a plurality of irradiation fields based on a beam diameter of the particular beam.

17. Control method according to one of the preceding claims, wherein a ge ^¬ closed contour train for producing a contour of the three-dimensional workpiece is assigned to one or more beams, in particular only one beam, regardless of the position of the contour train in the patches.

18. Control method according to one of the preceding claims, wherein the material to be solidified in the respective layer is divided into the surface pieces by means of a grid or a superposition of several grids.

19. The control method according to claim 18, wherein a first grid divides the layer into areas, each of which is reached by single or multiple rays, the areas via points of perpendicular ray incidence and an extent with respect to the surface of the carrier and / or an angle can be configured to the axis of the respective vertical beam incidence.

Define 20. The control method according to any one of claims 18 or 19, wherein a second grid which divides to be solidified material in the respective layer corresponding to a vector of alignment vectors of the beams, said vectors Fort ^¬ stride of the beams.

21. Control method according to claim 20, wherein the vector alignment of the vectors in adjacent patches of area is defined in such a way that vectors at the areas ^¬ borders do not converge on one another.

22. Control method according to one of the preceding claims, wherein the Sekti ^¬ onen are formed as substantially perpendicular to the gas flow direction of the gas flow extending columns, and wherein an extension of the respective column is defined parallel to the gas flow direction of the gas flow such that each of the columns a has the same number and / or a length equal to machining ^¬ tung vectors and / or a computational same exposure time.

23. Control method according to one of the preceding claims, wherein Wenig ^¬ least one section is divided so in surface properties, that an equal number of the usable to be solidified material in each patch beams for loading ^¬ clear of the sheet and / or a substantially equal number to vectors in each face piece and / or a substantially equal the sum of the length of the vectors in each face piece and / or a substantially equal exposure is achieved ^¬ time in each patch.

24. Control method according to one of the preceding claims, wherein in Wenig ^¬ least a section of each of the beams, which was allocated in the section of at least one piece ^¬ surfaces, an equal number and / or total length of vectors and / or the same exposure time and / or the same number of patches are assigned.

25. Control method according to one of the preceding claims, further comprising:

Determining, based on an irradiation of the material to be solidified in the layer in a first surface piece with one of the rays, an area with respect to the surface of the carrier in which an occurrence of smoke and / or splashes caused by the irradiation in the first Area piece arise, is expected, and

Determine based on the area in which the occurrence of

Schmauch and / or the splash is expected whether a second patch can be irradiated by the jet or another jet.

26. Control method according to one of the preceding claims, wherein the Strah ^¬ len laser beams include, in particular wherein all beams are laser beams.

27. The control method of claim 26, wherein all the laser beams in a chen Wesentli ^¬ same wavelength and / or a substantially equal power and / or a like, in particular punctiform, form the point of impact have.

28. The control method of claim 26, wherein the beams comprise at least two laser beams ^¬ which a different wavelength and / or under ^¬ schiedliche power and / or a different shape of the impingement

exhibit.

29. A computer program which can be ^loaded into a programmable control device, with a program code in order to execute at least part of a control method according to one of claims 1 to 28 when the computer program is executed on the control device.

30. A data carrier that contains the computer program according to claim 29, wherein the data carrier comprises an electrical signal, an optical signal, a radio signal or a computer-readable storage medium.

31. Control device for controlling a multi-beam device with one or more radiation sources for generating several beams of a system for Production of a three-dimensional workpiece by means of a generative layer construction process, the control device comprising:

one or more processors; and

contains a memory storing instructions that one or several of the processors ren executable, whereby the control means at least part (d) of the process according to one of claims 1 to 28 is operable to perform durchzu ^¬.

32. Manufacturing device for manufacturing a three-dimensional workpiece by means of a generative layer construction method, the manufacturing device comprising:

a multi-beam device having one or more radiation sources for generating a plurality of beams He ^¬; and

the control device according to claim 31.