Method and device for irradiating material with energy beams

Abstract

A method for irradiating a material (13) with at least one energy beam (AL) and an irradiation device (20) which can be used for this purpose are described, which are used in particular for locally melting the material (13), wherein an irradiation surface (AF) of the energy beam (AL) moves over the material (13). At least one first energy beam (EL1) and a second energy beam (EL2) are generated, the second energy beam (EL2) moves relative to the first energy beam (EL1), and the first energy beam (EL1) and the second energy beam (EL2) are coupled into an energy beam movement unit (23) in a common beam path (SA) so that they move together as a combined energy beam (AL) over the material (13). A method and a device (1) for additive manufacturing of manufactured products are also described.

Description

Technical Field

[0001] The invention relates to a method for irradiating a material with at least one energy beam, in particular in an additive manufacturing process, wherein the irradiation surface of the energy beam The invention also relates to an irradiation device for irradiating a material with at least one energy beam and to an apparatus for additively manufacturing a manufactured product, the apparatus comprising such an irradiation device. Background Art

[0002] In many processes, it is necessary to use energy beams, such as laser beams, to irradiate materials, especially to locally melt materials. A typical example of this is welding or laser welding with energy beams. Another large application area is additive manufacturing. Additive manufacturing processes are becoming increasingly important in the manufacture of prototypes and various manufactured products, as well as in mass production. Generally, "additive manufacturing processes" can be understood as such manufacturing processes that generally build manufactured products (hereinafter also referred to as "components") by stacking materials ("building materials") based on 3D digital structure data. Here, building mostly refers to, but not necessarily necessarily layer by layer. The synonym of additive manufacturing is usually the term "3D printing", and the manufacture of models, patterns and prototypes with the help of additive manufacturing processes is often called "rapid prototyping" and the manufacture of molds is also called "rapid molding". The core point in this process is the selective solidification of the building material, wherein in many manufacturing processes, it can be irradiated with radiation energy, such as electromagnetic radiation, especially light and / or thermal radiation, but if necessary, it can also be cured with particle radiation, such as electron radiation. Examples of methods that work with irradiation are "selective laser sintering" or "selective laser melting". In this case, thin layers of mostly powdery building material are repeatedly applied one on top of the other and in each layer, the locations that are to belong to the product to be produced after production are selectively solidified by spatially limited irradiation, i.e. the powder particles of the building material are partially or completely melted by the energy introduced locally by radiation at this location. After cooling, the powder particles are then connected to one another to form a solid.

[0003] In the present invention, the selective irradiation, in particular the movement of the energy beam over the irradiation surface on the structured area, is preferably carried out mostly according to a suitable irradiation strategy. For this purpose, the movement can be a previously generated energy beam or a deflection of the energy beam, for example in a conventional "scanning" process, for example by galvanometer mirrors with laser beams or by electromagnetic deflection in electron or particle beams. If necessary, the movement can also be carried out (at least partially) by the beam output unit or the irradiation device, in particular the energy beam source itself, which is, for example, in the form of a diode array, in particular a laser diode array.

[0004] Typically, a larger two-dimensional area, i.e., a larger surface on the building area, is irradiated during the curing process. Regardless of how the energy beam is generated and how its irradiation point on the building area is moved, it has proven to be advantageous to first virtually "divide" the area to be irradiated according to a selected pattern, for example into virtual "stripes", diamond patterns, checkerboard patterns, etc. The energy beam is then passed over the individual surfaces of the pattern, i.e., for example, stripes or areas, mostly in the form of so-called "shadow lines" (usually and hereinafter also referred to as "fillings"). In the stripe pattern, from a macroscopic point of view, the building material is cured successively along parallel stripes, and from a microscopic point of view, the irradiation surface of the energy beam on the building area moves along shadow lines that are adjacent to each other, and the shadow lines extend transversely to the corresponding irradiation stripes in the boundaries of the irradiation stripes.

[0005] In practical applications or in machines or devices known to date for additive manufacturing, energy beams, such as laser beams, are usually used that have a substantially rotationally symmetrical (i.e. circularly symmetrical) intensity distribution. Such a rotationally symmetrical intensity distribution is usually similar to a Gaussian distribution curve. In a Gaussian-shaped intensity distribution, the intensity is highest in the center of the energy beam and decreases in all directions radially outwards transversely to the propagation direction of the energy beam or the current beam path direction (hereinafter also referred to as "beam direction" or "beam axis") according to a Gaussian function or Gaussian distribution curve. This intensity distribution can be obtained from energy beam sources used to date, such as ordinary lasers, without further measures.

[0006] However, recent knowledge or research has shown that the exact shape of the intensity distribution of an energy beam, in particular a laser beam, can have a very insignificant influence on the entire production process, in particular, for example, on the energy consumption and / or the quality of the manufactured product, for example, its microstructure. A comparison between a laser beam with a Gaussian intensity distribution and a laser beam with a non-rotationally symmetrical intensity distribution, i.e. an elliptical intensity distribution, is shown, for example, in Tien T. et al., “Modulating the Ellipticity of the Laser Intensity Profile for Microstructure Control in Metal Additive Manufacturing” (Journal of Material Science), 2017, No. 128, pp. 197-206. It is also shown that not only the intensity distribution itself, but also its orientation with respect to the current direction of movement of the energy beam or its irradiation surface on the construction area (hereinafter also referred to as “scanning direction” without limitation to the general case) has an influence on the manufacturing process.

[0007] For example, currently in practice, the so-called "deep welding process" ("keyhole mode welding") is mostly used in the process of laser sintering or laser melting of metals. The welding process is defined as a deep welding process when a vapor capillary, also called a "keyhole", is formed. The incident energy beam, especially the laser beam, produces a molten bath composed of molten material or metal. If the surface of the molten bath of the material reaches its boiling point temperature through further continuous irradiation, the generated metal vapor presses the melt laterally and downwardly and thus produces vapor capillaries. The diameter of the keyhole is usually smaller than the diameter of the energy beam or laser beam. The advantage of this deep welding process is the high depth effect. That is, a deeper molten bath is formed compared to the beam diameter because no such evaporation occurs. Below, the welding process or melting process without evaporation is referred to as "thermal conduction welding" (also called "conduction mode welding" or "conduction laser welding"). However, compared with the thermal conduction welding process, the deep welding process also has many disadvantages, such as higher energy and material consumption. Which welding process is more suitable can depend on different process conditions or boundary conditions and can also change during the production process, for example depending on the location in the component to be produced. Whether the welding process is carried out as heat conduction welding or as a deep welding process depends on different parameters. The shape of the intensity distribution can also be a key parameter.

[0008] Depending on the current irradiation strategy, a specific intensity distribution is advantageous, wherein this can also change during the manufacturing process, in particular depending on which irradiation strategy is being used at the location within the component to be manufactured and, for example, whether the current irradiation of the building material is adjacent to an already fixed area and, if so, where this fixed area is located relative to the area currently to be cured.

[0009] Since very rapid changes of direction occur in some cases during the irradiation and a specific intensity distribution is usually always defined with respect to the current direction of movement, i.e. the scanning direction, the orientation or direction of the desired intensity distribution on the building area or material usually has to be changed. This requires the irradiation device to react quickly to changes in the intensity distribution. Another point is that, as will be described below, relatively large spatial intensity differences within the intensity distribution according to a precisely defined pattern are sometimes desirable in certain welding processes. Summary of the invention

[0010] The object of the present invention is to provide a suitable method and a suitable device for irradiating material, in particular for additive manufacturing processes, and a corresponding method and a device for additive manufacturing of manufactured products, which address these problems.

[0011] This is achieved on the one hand by a method for irradiating a material (also referred to below as “irradiation method”) according to claim 1 and an irradiation device according to claim 10, and on the other hand by a method for additive manufacturing of a manufactured product (also referred to below as “manufacturing method”) according to claim 9 and an apparatus for additive manufacturing according to claim 15.

[0012] In the irradiation method according to the invention, at least one first energy beam and a second energy beam are generated. This can be done, for example, by two separate energy beam sources, for example two lasers. However, in principle, the energy beam can also be first generated by one energy beam source and then divided, for example, in a beam splitter.

[0013] According to the invention, the second energy beam is moved relative to the first energy beam, and the first energy beam and the second energy beam moving relative thereto are coupled into the energy beam movement unit in a common optical path so that they move together as a combined energy beam, for example, in an additive manufacturing process, over a construction area with a building material. For this purpose, the energy beams are caused to run, for example, in parallel or coaxially, along the same optical path starting from the point of convergence, wherein the intensity distribution of the first energy beam and the second energy beam in a section plane extending perpendicularly to the beam axis of the combined energy beam (i.e., a virtual beam axis or the corresponding optical path to be defined later) does not significantly change at each current relative position on the path through the relevant energy beam movement unit, for example, when a scanner is used on a first scanning reflector, from the point of coupling into the energy beam movement unit to the irradiation surface. For example, if the intensity distribution of the first energy beam or the first energy beam is reflected or rotated, the intensity distribution of the second energy beam or the second energy beam is simultaneously reflected or rotated together, etc.

[0014] Therefore, the relative position between the first energy beam and the second energy beam is determined essentially only by the movement of the second energy beam relative to the first energy beam before coupling into the energy beam movement unit for combining the energy beams. Here, the movement of the second energy beam "relative to the first energy beam" is the movement of the second energy beam "seen" by an observer moving with the first energy beam. The relative movement of the second energy beam relative to the first energy beam can preferably be achieved by a separate, for example, first energy beam movement unit, an example of which will be provided later. The combined energy beam is then moved on the construction zone by the second energy beam movement unit, for example, by a conventional scanning mirror when using a laser beam. In other words, the relative positioning of the second energy beam in the combined energy beam (or in its intensity distribution) is completed only by the first energy beam movement unit. The second energy beam movement unit moves the common irradiation surface of the energy beams, that is, the irradiation surface of the combined energy beam (which is also called "unit beam"), wherein the combined energy beam changes its total intensity distribution accordingly based on the movement of the second energy beam relative to the first energy beam.

[0015] In particular, in these cases, the “combined energy beam” or “single beam” defined above is not generated, in which the second energy beam is coupled into the second energy beam motion unit by means of the first energy beam motion unit, so that the first energy beam and the second energy beam move away from the second energy beam motion unit and move away from the second energy beam motion unit toward the irradiation surface along the path or its optical path, respectively, so that the first energy beam and the second energy beam move away from the second energy beam motion unit and move away from the irradiation surface and move away from the second energy beam motion unit and move away from the irradiation surface. The situation is that when the first energy beam motion unit remains stationary at this point in time, when the position of the second energy beam motion unit changes at a specific point in time, the corresponding current relative positions of the first energy beam and the second energy beam (the intensity distribution) relative to each other on the path toward the irradiation surface change significantly. Because in these structures, the first energy beam motion unit must continuously (according to the current position of the second energy beam motion unit) compensate for the relative movement of the beam after the second energy beam motion unit. This is the case, for example, in the structures used in laser drilling machines according to US 2004 / 0129685 A1 or laser processing machines for cutting or welding according to US 2018 / 0154482 A1.

[0016] In a preferred variant, the beam path of the first energy beam and the "virtual beam path" of the second energy beam are simply extended coaxially so that they move in a coordinated manner as a superimposed combined energy beam over the material. The "virtual beam path" (or "virtual beam axis") of the second energy beam moving relative to the first energy beam is thus defined as extending through the geometric center of gravity of a "virtual cutting plane illumination surface" which is located in a cutting plane perpendicular to the (virtual) beam axis (as defined above), wherein the "virtual cutting plane illumination surface" is defined by the surface which the second energy beam in the cutting plane passes through with its spatial extension determined by its respective intensity distribution during a defined time period. The defined time period is preferably at least long enough that the second energy beam completes a movement cycle, particularly preferably a plurality of movement cycles, in a (preferably) repetitive movement pattern. The time period is particularly preferably exactly one cycle (the duration of one movement cycle) or an integer multiple of one cycle. For example, in a second energy beam that is circularly circling relative to the first energy beam, the "virtual beam path" of the second energy beam can also be regarded as an "average beam path" or "average beam axis", which is obtained by integrating the position of the actual beam axis of the second energy beam relative to the beam axis movement of the first energy beam over a specific integration time period. This will be described in more detail later, especially also based on the embodiments.

[0017] However, the "relative movement" of the second energy beam relative to the first energy beam or the position of the beam axis of the second energy beam within the total intensity distribution of the combined energy beam can in principle include all conceivable geometrical trajectories or trajectory curves (direction of the scanning path), i.e., translational or rotational movements or movement patterns. Particularly preferably, the relative movement of the second energy beam relative to the first energy beam or the position of the second intensity distribution of the second energy beam within the total intensity distribution extends on a closed curve, i.e., it can be called "periodic static". For example, the second energy beam can perform a circular or elliptical movement within the combined energy beam or relative to the first energy beam, or move along a closed polygon. Depending on specific requirements, other arbitrary curves as described are also feasible, such as any other polygon, a sawtooth line, a sinusoidal pendulum (also called oscillation welding), etc.

[0018] Accordingly, the total intensity distribution of the combined energy beam can also have any desired configuration or shape.

[0019] It should be pointed out here that in the present application, the "intensity distribution" of an energy beam generally includes the spatial shape or extension of the energy beam in a section plane (cross section) perpendicular to the beam direction or beam axis and the spatial distribution of the intensity in the cross section, i.e., in particular the positions of maxima and minima, etc. In addition, even if the section plane is viewed on the building area, i.e., shortly before the irradiation onto the building area, in most cases the intensity distribution in the section plane perpendicular to the beam direction or the direction of incidence does not exactly correspond to the intensity distribution directly on the surface of the building area or in the working surface, because the energy beam usually irradiates the building area obliquely. However, this does not exclude that during the method it always occurs again and again that the section plane coincides with the irradiation surface, because the energy beam is exactly perpendicular to the irradiation surface.

[0020] On the common beam path, ie after the first energy beam and the second energy beam movable relative thereto have been combined according to the invention, both energy beams as a combined energy beam each pass through the same beam-deflecting or beam-changing optical component on their path.

[0021] Therefore, according to the present invention, the irradiation device for irradiating materials has an energy beam source system, for example, preferably a laser system, to generate at least one first energy beam and a second energy beam, wherein, as described, the energy beam source system may have different energy beam sources for different energy beams, or may also have a beam splitter, etc.

[0022] Furthermore, the irradiation device has a first energy beam movement unit for moving the second energy beam relative to the first energy beam.

[0023] Finally, the irradiation device includes an energy beam combining mechanism and a second energy beam movement unit, which are constructed and arranged with respect to each other so that the first energy beam and the second energy beam moving relative to it are coupled into the second energy beam movement unit in a common optical path, so that they move together as a combined energy beam through the second energy beam movement unit on the material or construction area.

[0024] By using two energy beams, which can each have different intensity distributions and different absolute maximum intensities and irradiation surfaces of different sizes and configurations, and by moving the second energy beam relative to the first energy beam, an almost arbitrarily shaped and in particular very rapidly variable total intensity distribution can be achieved in the combined energy beam, which ultimately irradiates the material and determines the melting process or welding process. Due to the coupling of the energy beams or intensity distributions that are moved relative to one another into a common beam path by means of a second energy beam movement unit according to the invention, it can be ensured that the second energy beam movement unit, for example optical components of a scanner, and possibly subsequent components that may influence the direction of the energy beam, for example coupling windows in the structural space (process chamber) of the production device, have a negligible influence on the total intensity distribution of the combined energy beam.

[0025] In particular, an already existing production facility can be retrofitted with the irradiation device according to the invention, wherein an existing energy beam movement unit, such as a scanner, can be used as the second energy beam movement unit in the invention without modification.

[0026] In the method according to the invention for additive manufacturing of a manufactured product, the building material is selectively solidified as described at the outset and for this purpose is irradiated with at least one energy beam on the building zone. The above-described irradiation method according to the invention is used.

[0027] A similar additive manufacturing device according to the invention as described at the outset has at least one such irradiation device, which is constructed in the manner according to the invention or modified by retrofitting according to the invention. As a complete module, it is also possible to retrofit an already existing manufacturing device with an irradiation device according to the invention or to replace an existing irradiation device.

[0028] It should be pointed out here that the energy beam modification device or irradiation device according to the invention can also be used to configure a production device that works with a plurality of individual energy beams to solidify material on a building area at a plurality of locations in parallel. For this purpose, only a single or a plurality of, for example, all energy beams can be generated by the irradiation device according to the invention. That is, the corresponding production device is equipped with a plurality of individual irradiation devices according to the invention, for example.

[0029] The device for additive manufacturing, in particular the irradiation device, preferably has a control device so that the components of the energy beam modification device are controlled in a suitable manner in coordination with other components of the device for additive manufacturing. In this case, the control device may in particular include a plurality of sub-control devices, which are, for example, assigned to the irradiation device, in particular the first and / or second energy beam movement unit, and / or other components and act together in a suitable manner. The control device or the sub-control device may also be implemented in full or in part in the form of software.

[0030] Particularly advantageous further designs and improvements of the invention are derived from the dependent claims and the following description, wherein an independent claim in one claim category may also be improved similarly to dependent claims and embodiments of another claim category and in particular individual features of different embodiments or variants may also be combined to form new embodiments or variants.

[0031] The combined energy beam is usually moved over the material or the building area at a preset scanning speed which can also be changed dynamically. Particularly preferably, the simultaneous relative movement of the second energy beam with respect to the first energy beam or the movement of the second energy beam within the combined energy beam is carried out at a preset relative speed (which can also be dynamically controlled) whose value is much greater than the value of the scanning speed.

[0032] Preferably, the relative speed of the first energy beam between the first energy beam and the second energy beam or within the combined energy beam is at least twice the value of the scanning speed, more preferably at least five times greater, even more preferably at least 10 times greater, particularly preferably 15 times greater, and very particularly preferably even 100 times greater.

[0033] The value of the relative speed is therefore preferably at least 5 m / s. Particularly preferably, it is at least 10 m / s, more preferably at least 20 m / s, very particularly preferably at least 50 m / s.

[0034] In selective laser melting or selective laser sintering, the values ​​of the scanning speed are usually in the range of 0.01 m / s to 5 m / s, for example. In electron beam melting, significantly higher speeds, for example 20 m / s or more, can also be achieved. The scanning movement is usually much slower than the relative movement of the second energy beam relative to the first energy beam.

[0035] By moving the second energy beam relative to the first energy beam, it is advantageously possible to generate a time-integrated total intensity distribution of the combined energy beam of almost any design over a specific time period. The integration time period should preferably be long enough so that the second energy beam can essentially pass through its path relative to the first energy beam, for example a movement cycle. Thus, the integration time period may include at least one movement cycle in the above-mentioned and hereinafter described periodic movement. Preferably, the integration time period is a longer time, for example an integer multiple of a movement cycle.

[0036] Since the irradiation surface of the combined energy beam moves on the material, the relatively fast relative movement of the second energy beam relative to the first energy beam can ensure that there is sufficient "dwell time" (or irradiation time period) at any position during the scanning of the combined energy beam over the construction area, so that the aforementioned integration time period is at least approximately achieved. In other words, the relative movement speed should preferably be large enough so that due to the inertia of the heat input (heat capacity of the material) the superimposed intensity distribution of the first and second energy beams acts on the building material as a "quasi-static" total intensity distribution during the time period of the physical process of heat conduction. As can be seen from the diagram, in this case, radiation energy corresponding to the total intensity distribution is essentially supplied to the material over the integration time period, because due to the low scanning speed, even if the scanning movement (for this image) is considered to be absent, during the dwell time of the combined energy beam (which is longer than the relative movement) at one position, the second energy beam scans all relative positions, preferably even multiple times, with its intensity distribution within the total intensity distribution of the combined energy beam. In the continuous scanning movement, there will naturally always be small local deviations in each revolution, but due to the usually high scanning speed and the relatively slow thermal diffusion, this deviation has no significant effect on the heat distribution in the vicinity of the actual irradiation surface, so that the above-mentioned presentation image almost perfectly represents the object. In other words, the material or material area to be melted at a specific point in time, when the combined energy beam irradiates the corresponding area, roughly "sees" the approximately "static" total intensity distribution of the combined energy beam. The minimum relative speed required for this can therefore also be closely related to the material parameters of the building material used, in particular the specific heat capacity. Thus, for example, the Fourier number Fo=(a·Δt) / d 2 As small as possible in order to achieve a "quasi-static" total intensity distribution as well as possible, where a is the thermal conductivity (material constant), Δt is a characteristic time period (e.g. cycle time), and d is a characteristic length (e.g. the extension of the total intensity distribution, such as the radius). The smaller the Fourier number, the less heat is "transported" in the relevant time period, i.e. the cycle time of one revolution of the second energy beam.

[0037] In this method for irradiating a material, a first energy beam and a second energy beam are generated and at least partially superimposed in the manner described and moved over the material at a predetermined speed, wherein the second energy beam moves relative to the first energy beam at a predetermined relative speed, the value of which is much greater than the value of the scanning speed. This method for irradiating a material can also be coupled into a common energy beam motion unit independently of coupling into a common beam path, when the movement of the two energy beams can be coordinated particularly easily by coupling into a common energy beam motion unit as described above. However, in principle, this can also be achieved by simply coordinating or synchronously controlling two separate energy beam motion units or scanners on the construction area.

[0038] In this case, as described above, the irradiation device according to the present invention requires an energy beam source system for generating at least a first energy beam and a second energy beam. The irradiation device also requires a first energy beam motion unit and a second energy beam motion unit and a control device, which controls the irradiation device so that the first energy beam and the second energy beam are at least partially superimposed into a combined energy beam and move in a coordinated manner on the material or construction area at a preset scanning speed, wherein the second energy beam moves at a preset relative speed relative to the first energy beam, and the value of the relative speed is much greater than the value of the scanning speed.

[0039] A first energy beam and a second energy beam moving relative to the first energy beam can be coupled into a common beam path by means of a beam combiner of the irradiation device. The beam combiner can be connected downstream of the first energy beam movement unit (i.e. arranged downstream in the beam direction) and upstream of the second energy beam movement unit (i.e. arranged upstream in the beam direction) in order to couple the first energy beam and the second energy beam, for example, parallel to one another, for example with a small spacing of the beam path relative to the diameter of one of the beams (this will be described below by way of example), into the second energy beam movement unit, for example, onto a first scanning mirror of a conventional scanning system.

[0040] The beam combiner preferably has a polarizer, particularly preferably a thin-film polarizer, or can be formed from it.

[0041] Preferably, during the irradiation method, the second energy beam is intensity modulated as a function of its relative position relative to the first energy beam or as a function of its current position in the combined energy beam during the relative movement. Alternatively or additionally, the second energy beam can also be intensity modulated as a function of the current direction of movement of the combined energy beam over the material or the construction zone, i.e. the current scanning direction, i.e. as a function of the direction of movement of a corresponding element of the energy beam movement unit, for example a scanning mirror.

[0042] In principle, however, the intensity of the first energy beam can also be modulated.

[0043] In the intensity modulation, it is preferred that the minimum intensity is at least always greater than 0, ie the second energy beam within the combined energy beam always contributes to the overall intensity increase at the corresponding point in the overall intensity distribution of the combined energy beam.

[0044] Intensity modulation makes it possible to generate a combined energy beam whose total intensity distribution has, for example, an absolute maximum and / or an absolute minimum only at a single location and, if necessary, local maxima and / or minima at other locations of the total intensity distribution relative to the corresponding periphery or along a specific cutting direction or along a specific intensity variation curve, i.e. along a defined path within the total intensity distribution, as will be described below.

[0045] Preferably, the energy beam source system of the irradiation device is configured and / or the irradiation device has an energy beam modulation unit so that the intensity of the second energy beam is modulated in a desired manner. For this purpose, the irradiation device can have a control device, which controls the energy beam source system, in particular the second energy beam source (if it is driven separately by the first energy beam source) and / or the energy beam modulation unit accordingly.

[0046] In principle, the first energy beam and the second energy beam can have any intensity distribution. Preferably, they have qualitatively and / or quantitatively different intensity distributions, very particularly preferably qualitatively and quantitatively, ie completely different shapes.

[0047] In a particularly preferred variant, the first energy beam has an intensity distribution which is essentially (ie within normal tolerances) rotationally symmetrical about the beam axis.

[0048] The term "rotationally symmetric" here refers to a rotation axis coaxial with the beam direction of the energy beam. Up to this point, as described above, the energy beam is usually generated so that it forms a rotationally symmetric, i.e., for example, a Gaussian-shaped intensity distribution. In contrast, the term "non-rotationally symmetric" or "substantially non-rotationally symmetric" is understood below to mean an energy beam whose intensity distribution is intentionally generated to a significant extent non-rotationally symmetric or is correspondingly influenced by targeted modification of the beam and / or by generating a combined energy beam with a non-rotationally symmetric total intensity distribution according to the invention. This does not include energy beams that should themselves have a common rotationally symmetric, for example, Gaussian-shaped intensity distribution and only have undesired deviations from the rotational symmetry, which are caused, for example, by accidental deformations or other defects of the system for generating and / or moving the energy beam. For example, if the intensity distribution of the desired output energy beam is mathematically described as a function I(r, φ) of the position of the polar coordinates r and φ (in a plane perpendicular to the beam direction), then the intensity distribution can preferably be referred to or defined as "non-rotationally symmetric" if no origin can be found in the intensity distribution, which satisfies the following properties for any m and any r under the condition m≥2:

[0049]

[0050] Therein, ε≤0.01, preferably ε≤0.05, more preferably ε≤0.1, and even more preferably ε≤0.2. Specifically, the intensity distribution defined thereby is not only not rotationally symmetric, but also not rotationally symmetric.

[0051] Particularly preferably, the first energy beam has a so-called "top hat" or "flat-top intensity distribution". This intensity distribution is characterized in that it has a spatially relatively uniform intensity distribution over the beam cross section. That is, the distribution function can be displayed as having relatively smooth, flat surfaces and relatively sharp edges. In a cross section through the beam axis, this "top hat" or "flat-top intensity distribution" appears as a rectangular configuration. This configuration can be described by a Heaviside function (step or jump function).

[0052] With the help of a top hat intensity distribution, a defined relatively uniform basic intensity can be ensured in the combined energy beam, ie in the total intensity distribution. In addition, suitable beam shaping units, such as diffractive optical elements (DOEs), are provided for such a top hat intensity distribution.

[0053] Particularly preferably, the second energy beam also has an intensity distribution that is substantially rotationally symmetrical about the beam axis, i.e. within normal tolerances. The second energy beam can, for example, particularly preferably have a Gaussian intensity distribution. Such a Gaussian intensity distribution generally does not require a beam shaping unit, since most energy beam sources, in particular lasers, generate beams with a Gaussian-shaped intensity distribution as described.

[0054] By combining a first energy beam with a top-hat intensity distribution for providing a uniform base intensity in the overall intensity profile and a second energy beam with a Gaussian intensity distribution which moves very rapidly in the overall intensity distribution, an almost arbitrary overall intensity distribution can be generated in the combined energy beam.

[0055] Preferably, the second energy beam is "smaller" or "denser" than the first energy beam, i.e., the second energy beam has a smaller maximum beam expansion than the first energy beam, especially when coupled into the common optical path via the energy beam motion unit (i.e. at the coupling-in location, for example on the first scanning mirror of a conventional scanning system).

[0056] In this context, beam expansion is to be understood as any dimension or distance that passes through the beam transversely (to the beam axis), i.e., for example, the beam diameter or beam width, wherein the beam width is always to be understood as the extension perpendicular to the current direction of movement of the irradiated surface on the construction area. In this context, in particular when the energy beam does not have a rotationally symmetrical intensity distribution, the distance does not necessarily need to pass through the beam axis or the center of the (total) intensity distribution. In this context, beam expansion is defined as extending over a defined distance from one edge of the intensity distribution to the opposite edge, wherein the edge is arbitrarily defined here as 99% of the radiation power of the energy beam being within this edge (i.e., in the area enclosed by the edge).

[0057] For example, the beam spread of the first energy beam can be at least 500 μm, preferably at least 700 μm, more preferably at least 900 μm, even more preferably at least 1000 μm, even more preferably at least 1100 μm, even more preferably at least 1200 μm, even more preferably at least 1500 μm, particularly preferably at least 2 mm. Alternatively or additionally, the maximum beam spread of the first energy beam is at most 10 mm, preferably at most 6 mm, more preferably at most 4 mm, particularly preferably at most 3 mm.

[0058] The beam spread of the second energy beam, which moves relative to the first energy beam or preferably within the beam spread of the first energy beam, is at least 20 μm, preferably at least 50 μm, particularly preferably at least 80 μm. However, the maximum beam spread of the second energy beam is at most 300 μm, preferably at most 200 μm, particularly preferably at most 100 μm.

[0059] The beam spread of the second energy beam is preferably at most 1:3, more preferably at most 1:5, even more preferably at most 1:10, even more preferably at most 1:20 to the beam spread of the combined energy beam and / or the beam spread of the first energy beam.

[0060] When the first energy beam and the second energy beam and the combined energy beam are essentially circular in shape, the ratio of the diameter of the second energy beam to the diameter of the combined energy beam and / or to the diameter of the first energy beam is preferably at least 1:100, particularly preferably at least 1:50.

[0061] Very particularly preferably, the beam spread, for example diameter, of the first energy beam and the beam spread or diameter of the combined energy beam (with top-hat intensity distribution) is 1000 μm and the second energy beam (with Gaussian intensity distribution) has a beam spread, for example beam diameter, of 80 μm.

[0062] As mentioned at the beginning, the relative movement of the second energy beam relative to the first energy beam (or the movement of the second energy beam within the combined energy beam) can be carried out on any trajectory and in any manner. However, preferably, the relative movement of the second energy beam relative to the first energy beam is carried out periodically, i.e., the second energy beam is always repeatedly driven to the same position on a closed curve within the combined energy beam. In particular, in the case of a linear, purely translational scanning movement of the combined energy beam, it is particularly preferred that the second energy beam passes through the same position (relative to the first energy beam) at the same time intervals during the relative movement.

[0063] Additionally or alternatively, the intensity is also modulated periodically accordingly. For example, a control signal for intensity modulation of the second energy beam, preferably a generator signal of a second energy beam source for generating the second energy beam, can be designed as a sinusoidal signal, etc. In this way, periodic intensity modulation is automatically achieved.

[0064] If, for example, as described below, the intensity distribution is changed, for example so that the maximum is shifted, this can then be achieved, for example, simply by a phase shift of the generator signal.

[0065] The first energy beam source and / or the first energy beam movement unit and / or the energy beam modulation unit can be designed and correspondingly controlled by the control device in order to ensure such a periodic relative movement or intensity modulation.

[0066] Particularly preferably, the relative movement and / or intensity modulation of the second energy beam is uniform, in particular in a linear, purely translational scanning movement of the combined energy beam. Relative movement is understood to mean that the value of the relative movement speed remains constant and does not change during the movement, but only the direction of movement changes; intensity modulation is understood to mean that the modulation is performed continuously.

[0067] Very particularly preferably, the second energy beam moves along the edge of the intensity distribution of the first energy beam. This is preferably done in that at least one maximum of the intensity distribution of the second energy beam, i.e. the center in a Gaussian curve, moves within a surface of the first intensity distribution defined by the edge. Particularly preferably, the edge of the total intensity distribution of the combined energy beam is substantially identical to the edge of the intensity distribution of the first energy beam or is at least relatively close to one another, for example <20 μm, so that the total diameter of the combined energy beam is substantially defined by the diameter of the first energy beam. Preferably, the size difference between the edge of the total intensity distribution of the combined energy beam and the edge of the intensity distribution of the first energy beam is at most approximately 40%, more preferably at most approximately 25%, particularly preferably at most approximately 15% of the beam expansion of the (“smaller”) second energy beam. Preferably, at least one maximum of the intensity distribution of the second energy beam is located within the intensity distribution of the first energy beam.

[0068] The process in which the second energy beam travels along a circular path along or within the edge of the intensity distribution of the first energy beam is preferred in particular when the first energy beam has a rotationally symmetrical or circular intensity distribution, very particularly preferably a top-hat intensity distribution.

[0069] In order to realize such relative movement of the second energy beam relative to the first energy beam along a closed track, especially a circular track, a rotating optical element, such as a beam displacement element or a reflector, especially a so-called plate and / or a reflector, can be preferably used in an optical energy beam, such as a laser beam. That is, the first energy beam movement unit preferably includes a rotating unit with a rotatable optical element. The optical element can be driven, for example, by a suitable motor, wherein the rotation can be performed relatively quickly, that is, the desired rapid rotation or movement of the second energy beam is numerically realized relative to the scanning speed. For example, the rotation of the optical element rotates at about 400 revolutions per second when the radius of the circular movement of the second energy beam extending parallel to the virtual beam axis is 2 mm and the movement speed (i.e., the orbital speed thereof on its circulating track) is 5 m / s, rotates at about 2500 revolutions per second when the movement speed of the second energy beam is 31 m / s, and rotates at about 4000 revolutions per second when the movement speed of the second energy beam is 50 m / s.

[0070] Preferably, the optical path of the second energy beam is deflected by such a rotation unit with a rotatable optical element, so that the optical path rotates around a "virtual rotation axis" on a "virtual cylindrical outer surface" and at the same time always runs parallel to the virtual rotation axis. The virtual rotation axis corresponds to the previously defined virtual beam axis or virtual optical path of the second energy beam.

[0071] There are different approaches for realizing such a rotating unit.

[0072] In a preferred variant, the first energy beam movement unit has a transmission beam displacement element, preferably a flat plate or a plane-parallel plate, as described. The beam displacement element is arranged, for example, tiltably in the beam path of the second energy beam and rotatably about a rotation axis, wherein the rotation axis runs coaxially with the (incoming) beam path of the incoming or incident second energy beam. As a result, the outgoing beam path can be rotated about the rotation axis at any time, parallel to the rotation axis and with a defined axial spacing. The virtual rotation axis of the second energy beam and the real rotation axis of the beam displacement element are coaxial with each other. This axial spacing can be set or changed, for example, by the thickness of the correspondingly used flat plate.

[0073] In a specific implementation, for example, an optical element, in particular a flat plate, can be arranged in a rotatable hollow shaft with a suitable drive motor, wherein the actual beam axis or actual optical path of the incoming second energy beam extends through the longitudinal axis of the hollow shaft, which is also the rotation axis of the hollow shaft and the virtual beam axis of the virtual optical path of the outgoing second energy beam.

[0074] In another preferred variant, the first energy beam movement unit comprises a reflector as a rotatable or rotatable optical element during operation, such as a mirror. The reflector or mirror can also be arranged, for example, tilted in the beam path of the second energy beam (i.e., the mirror surface is tilted relative to the incoming beam in order to deflect it) and can be arranged rotatably about the axis of rotation (provided with a suitable controllable drive motor) so that the mirror plane is not perpendicular or parallel to the axis of rotation. This allows the outgoing beam path of the second energy beam to extend at an angle away from the axis of rotation of the optical element that rotates during operation, due to the tilted position of the mirror.

[0075] Preferably, the reflector or mirror is constructed and arranged such that, starting from a perpendicular to the axis of rotation, the inclination of the mirror plane changes periodically between an angle +α and an angle −α. During the rotation of the mirror or its limited movement, the input angle of the incoming second energy beam relative to the mirror plane and the output angle of the outgoing second energy beam change accordingly. The rotating second energy beam preferably moves on a cone surface, wherein the cone tip is located in the mirror plane.

[0076] Depending on the specific configuration, the (imaginary extension of) the rotation axis of the optical element runs coaxially with the (incoming) beam path of the incoming second energy beam, but a configuration with an inclined rotation axis of the optical element is also possible. Examples of this will be described later.

[0077] According to a preferred design of the present invention, another optical element is arranged downstream of the reflector or mirror in another optical path of the second energy beam, and the other optical element reverses the real optical path emitted from the reflector or mirror so that it rotates around the virtual rotation axis on the circumference of the above-mentioned virtual cylinder as the rotatable optical element rotates.

[0078] In other words, all possible beam paths of the second energy beam are located parallel to one another in the section of the beam path immediately after the crossing of the other optical element, i.e. on the side of the optical element facing away from the rotatable mirror and from which the energy beam emerges. For this purpose, an optical element can preferably be used, in which the center of rotation of the rotating mirror is located in its focus. In other words, the focus of the optical element (on the side of the optical element facing the mirror) is arranged as close as possible, preferably just on the surface of the rotating mirror and as close as possible, preferably just at the point where the axis of rotation of the mirror intersects the mirror plane. Particularly preferably, the second energy beam impinging on the mirror plane of the mirror during operation intersects the axis of rotation of the rotating mirror in the mirror plane.

[0079] As the optical element, for example, a lens group and / or a converging lens, such as a biconvex lens, can be used. The focal point of the optical element on its side facing away from the mirror can be nominally infinite. The advantage of this embodiment is that the real beam path of the output of the second energy beam moves parallel to the virtual rotation axis at the axis spacing as described above at each time point and rotates around the virtual rotation axis.

[0080] Preferably, an axial spacing of the beam path of the second energy beam parallel to its axis of rotation and later relative to the beam path of the first energy beam can be set.

[0081] According to a first embodiment, the first energy beam movement unit comprises a device for setting or changing the tilt position of the reflector or mirror relative to the rotation axis of the reflector or mirror. Even when using a simple optical element with a fixed focus, the radius of the periodic movement of the second energy beam around its rotation axis can be preferably changed during the operation of the irradiation device according to the invention. The optical element located downstream of the mirror in the beam path is structurally adapted to the preset range of the angle of incidence of the second energy beam so that it has a single focus on the input side, which is always located in the mirror plane (preferably at the rotation center of the rotating mirror) when the tilt position of the mirror is different, that is, when the angle of the second energy beam impinging on the optical element is different, and an additional device for adjusting the distance between the mirror and the converging lens is not necessary here. According to this first embodiment, the radius of the periodic movement of the second energy beam around its rotation axis changes at least in steps, preferably continuously.

[0082] According to a second embodiment, the first energy beam movement unit comprises a focusable system as an optical element (also called "zoom"), which can change the focal length. Preferably, the second embodiment also includes a device for adjusting the focus of the second optical element (also refers to the focus on the side facing the rotating mirror in the optical path), so that the focus can change when the focal length changes, so that it is exactly arranged in the mirror plane with a small (positive or negative) time deviation relative to the focal length change. Particularly preferably, the focusable system is designed to be confocal, so that the focus on the mirror plane remains constant when the focal length changes. The optical device forming the optical element is preferably designed as described so that the emitted beams are parallel to each other, that is, the focus is nominally at infinity. According to a second embodiment, the radius of the periodic movement of the second energy beam around its rotation axis can be changed at least in steps, preferably continuously.

[0083] According to a third embodiment, the first energy beam movement unit comprises an adjustment device for adjusting the distance between the mirror and the optical element along the rotation axis of the second energy beam. The larger the distance is selected, the further away (radially) the second energy beam impinges on the optical element from its rotation axis, and thus the larger the radius of the movement of the emitted second energy beam around its rotation axis across the optical element. Preferably, the third embodiment also comprises a device for adjusting the focus of the optical element (also referred to as the focus, which is located on the side of the optical path facing the rotatable mirror), as described, so that the focus can change when the distance changes, and is therefore arranged exactly in the mirror plane with a small (positive or negative) time deviation relative to the distance change.

[0084] According to a fourth embodiment, the first energy beam motion unit includes at least one conical lens or a system of one or more lenses or mirrors having the same function as an optical element. The conical lens is composed of a conical lens segment and a cylindrical lens segment integrally connected thereto along the direction of the beam. The conical lens is usually configured to be rotationally symmetrical. The inclination of the outer surface of the cone is adjusted according to the preset angular range of the incoming second energy beam, so that the beams emitted from the conical lens are always parallel to each other or also parallel to the rotation axis of the second energy beam and at the same time parallel to the optical axis of the conical lens. For this, the second energy beam must be irradiated onto the outer surface of the cone at a constant angle. The conical lens thus converts the incoming light path (regarded as "quasi-static") in the shape of a conical surface into the emitted light path of a cylindrical surface. In other words, the conical lens is configured so that the beam diverged by the tilted position of the rotating mirror relative to the beam axis is parallel to the beam axis. Preferably, the conical lens is arranged relative to the rotatable mirror so that the optical axis of the conical lens intersects with the mirror plane at the center of rotation. In order to obtain a change in the distance (radius) between the rotating second energy beam and its rotation axis, the distance between the axicon and the rotating mirror along the rotation axis of the second energy beam or the optical axis of the axicon can be changed. To this end, the first energy beam movement unit preferably also includes an adjustment device.

[0085] The above-mentioned embodiments may also be combined in appropriate ways.

[0086] When the first energy beam and the second energy beam are superimposed, the virtual rotation axis or the imaginary extension of the rotation axis about which the optical path of the second energy beam rotates is coaxial with the optical path of the first energy beam, thereby ensuring that the intensity distribution of the second energy beam rotates on a circular orbit around the center of the intensity distribution of the first energy beam, that is, around the beam axis of the first energy beam.

[0087] In particular, the above-described device and method can generate a particularly preferred total intensity distribution which (as described above) is parameterized by time integration, for example with one or more integration periods of the movement period of the second energy beam relative to the first energy beam.

[0088] The total intensity distribution has at least one local minimum in the middle region along at least one secant in a sectioning plane extending perpendicularly to the beam axis of the combined energy beam along the edge curve of the total intensity distribution. A "secant" in the context of the invention extends through the surface of the intensity distribution from one side to the other, i.e. the secant cuts the edge of the intensity distribution at exactly two mutually spaced locations and can, but does not necessarily, extend through the beam axis or the center of the intensity distribution (in which case the secant corresponds to the diameter), regardless of the specific shape or course of the edge curve or edge. Thus, in particular, the secant is not just on the edge curve. Preferably, the secant is transverse to, preferably substantially perpendicular to, the scanning direction of the energy beam on the construction zone. It is also preferred that the secant passes through the geometrical center of gravity of the shape or shape of the intensity distribution in the sectioning plane.

[0089] In this case, a "middle region" is to be understood as a central region of the total intensity distribution, i.e., a local minimum is located in the region of a secant through the middle region. The middle region is to be distinguished from an edge region of the total intensity distribution which runs along the above-defined edge of the total intensity distribution and extends from the edge into the total intensity distribution, and more specifically preferably relates to, for example, at least one beam spread or beam width of a second energy beam moving relative to the first energy beam.

[0090] Preferably, 99% of the energy of the second energy beam, which is moved relative to the first energy beam, is in a marginal region of the total intensity distribution.

[0091] Furthermore, the total intensity distribution preferably has an intensity curve which (completely) circumscribes an edge of the total intensity distribution (substantially parallel to, i.e. equidistantly inwardly from, e.g. centered relative to the edge), the intensity curve having a maximum at at least one location and a local minimum in the region opposite the maximum on the intensity curve. As described above, an "intensity curve" is to be understood here as the intensity course of the intensity distribution as a function of a location along a defined, respectively selected curve. The term "local minimum" is to be understood here as a minimum value with respect to the variation of the intensity values ​​on the intensity curve, i.e. when the intensity is measured along the intensity curve and plotted in a diagram, a local minimum is thus shown here.

[0092] The "region opposite to the maximum value" on the intensity variation curve is to be understood as a region of an angle of 60°, preferably up to 50°, more preferably up to 40°, more preferably up to 30°, and particularly preferably up to 10°, which is enclosed in both directions along the intensity variation curve starting from a position diagonally opposite to the maximum value on the intensity variation curve. Very particularly preferably, the local maximum is located on the intensity variation curve essentially (i.e. within normal tolerances) diagonally opposite to the maximum value. The term "diagonally" in a narrow sense relates in particular to intensity variation curves with a circular course. In general, however, in irregularly shaped intensity variation curves, for example, the corresponding opposite points can be constructed so that the secant, starting from the maximum value, passes through the center of gravity of the surface enclosed by the edge of the intensity distribution, and the secant cuts the intensity variation curve at this point, which is the "diagonally" opposite point in the present application.

[0093] In a preferred total intensity distribution or combined energy beam, a higher intensity is intentionally achieved in the peripheral region along the edge, preferably circumferentially, than in the central region. A local minimum is present in the center, i.e. at the beam axis and / or at a small distance therefrom, for example in the halfway point from the center to the edge.

[0094] By providing a second parameterization for the total intensity distribution with maxima and relative minima along the intensity curve around the edge, the total intensity distribution of the combined energy beam is also intentionally made rotationally asymmetrical about an axis of rotation running coaxially to the direction of incidence of the combined energy beam on the material or the structure region.

[0095] As will be described later with reference to the exemplary embodiments, the total intensity distribution can be provided with a local increase in intensity, which extends in an at least partially annularly surrounding edge region of the total intensity distribution (or in a section of an annular edge region). In other words, the total intensity distribution has an increased intensity relative to the central region (i.e. relative to the local maximum region of the periphery) in at least one region along its contour at a small distance from the edge. The region between the central region and the edge defined above is understood here as the edge region. The surrounding intensity profile preferably extends at least partially along the partially annularly surrounding edge region.

[0096] In particular, an overall intensity distribution with a sickle-shaped intensity increase can be generated by a local intensity increase at one point of the intensity curve and a local minimum in this region on the opposite side of the intensity curve.

[0097] Preferably, the maximum value is located in the edge region of the total intensity distribution in the front along the scanning direction on the surrounding intensity variation curve. Therefore, the local minimum value is located in the edge region of the intensity variation curve in the rear along the scanning direction. This does not exclude the presence of other local maxima and local minima on the intensity variation curve.

[0098] The "edge area located in the front" along the scanning direction may preferably be a distance of at most approximately 2 / 3π·r on the arc (r is the radius of a circle, which may be equivalent to the radius of curvature depending on the beam shape. For any beam shape or shape of the intensity distribution, the contour periphery of the beam shape is defined as 2π·r), more preferably a distance of at most approximately 1 / 2π·r, even more preferably a distance of at most approximately 1 / 3π·r, particularly preferably a distance of at most approximately 1 / 2π·r, even more preferably a distance of at most approximately 1 / 3π·r, particularly preferably a distance of at most approximately 1 / 6π·r, wherein the surface surrounding the intensity distribution detected from the corresponding action area thus obtained is the point located at the front along the scanning direction.

[0099] In particular, the circular intensity distribution can have an angular range of a maximum of 120°, more preferably a maximum of 90°, even more preferably a maximum of 60°, and particularly preferably a maximum of 30° (the circular intensity distribution is a ring segment), wherein the surface detected from the corresponding angular range surrounds the point of the intensity distribution that is located furthest forward in the scanning direction.

[0100] Preferably, the minimum value in the intensity curve is higher than a local minimum value in the middle region of the intensity distribution, ie in the center or close to the center.

[0101] In the region of the minimum in the middle region, the intensity is preferably at a maximum of 1.5 MW / cm 2 Preferably, the intensity is at least 0.05 MW / cm 2 .

[0102] Preferably, the intensity on the intensity curve along the edge is higher than the local minimum in the middle region of the total intensity distribution at each location. That is, the total intensity distribution has an annular overall intensity increase in the edge region, but the intensity increase value is different depending on the position on the circumference.

[0103] The ratio of the maximum intensity value on the annular intensity curve, i.e., for example, at a point of local intensity increase along the edge, to the local intensity minimum, especially in the middle region of the overall intensity distribution, is preferably at most 10:1, preferably at most 9:1, more preferably at most 8:1 and particularly preferably 7:1.

[0104] Preferably, the ratio of the minimum intensity value in the annular intensity profile to the local intensity minimum is at least 1.5:1, preferably at least 2:1, more preferably at least 3:1, particularly preferably at least 4:1.

[0105] Preferably, the maximum value on the intensity curve along the edge is at least 1.5 times, more preferably twice, even more preferably three times, and particularly preferably four times higher than the local minimum value in the opposite region on the intensity curve. Likewise preferably, the maximum value on the intensity curve along the edge is at most eight times, more preferably seven times, even more preferably six times, and particularly preferably five times higher than the local minimum value in the opposite region on the intensity curve.

[0106] The (position-dependent) function of the intensity values ​​along the intensity curve can in principle run arbitrarily between the maximum and the minimum in the relative region on the intensity curve. It is particularly preferably a curved run. It is preferably a "smooth" function without abrupt changes. Preferably, the function can be differentiated at least once, preferably at least twice, particularly preferably any number of times at any point.

[0107] The intensity of the second energy beam is preferably modulated by controlling the power of the second energy beam moving relative to the first energy beam. Intensity modulation is particularly preferably performed with a smooth and periodic control signal. Preferably, the function of the control signal can be differentiated at least once at any position along the intensity variation curve, more preferably at least twice, and particularly preferably any number of times, corresponding to the above-mentioned preferred intensity value function. For example, an ideal theoretical control signal can be approximated or accurately mapped by a trigonometric function or a linear combination of trigonometric functions such as sine or cosine signals. Any other control program or algorithm can also be used, which periodically repeats a function defined in one cycle (for example from -π to +π). The movement of the maximum and minimum values ​​of the intensity of the second energy beam along its (relative) motion trajectory can be performed by a phase shift of the periodic control signal.

[0108] A possible generator signal for modulating the second energy beam can be described, for example, by the following function:

[0109]

[0110] Here, A is the difference between the local minimum and the local maximum, ω is the angular velocity of the second energy beam about its virtual axis of rotation, t is the time, θ(t) is the above-mentioned (time-dependent) phase shift of the maximum and minimum shifts on the intensity profile, the index n is a natural number and c is a constant. By increasing the index n, the intensity profile can be implemented so that it drops more steeply from the local maximum in both directions.

[0111] As mentioned above, one of the advantages of the present invention is that the total intensity distribution of the combined energy beam can be changed very quickly. Preferably, the total intensity distribution of the energy beam is arranged substantially axisymmetrically or substantially non-axisymmetrically about the symmetry axis along the scanning direction in dependence on the irradiation surface environment parameters.

[0112] In this case, an "axisymmetric" arrangement is to be understood as meaning that the axisymmetry exists within the usual tolerance range. An "essentially non-axisymmetric" arrangement means that the axisymmetry is intentionally not maintained, ie the deviation from the axisymmetry exceeds the tolerance.

[0113] An irradiation surface environment parameter may be understood in particular as a parameter which indicates whether the current track (eg a filling) runs alongside already solidified material, ie for example whether it is a first track which does not laterally adjoin a preceding track or a further track.

[0114] Because the cured material has different thermal properties than the uncured material, compensation can be achieved by intentionally deviating from the axial symmetry with respect to the scanning direction. For example, for this purpose, the maximum value on the intensity variation curve along the edge can be not located exactly in front along the scanning direction, but a distance away from the already cured track (for example, the adjacent filling part that has been processed) or closer to it. That is, the total intensity variation curve rotates away from or towards the already cured track about the maximum value around the rotation axis of the intensity variation curve. At the same time, the minimum value on the intensity variation curve of the total intensity distribution is rotated towards or away from the already cured track. In which direction to rotate, for example, it can depend on whether the adjacent already cured track is hot or has cooled. The cooled hardened track has a larger mass and absorbs energy poorly because the "smooth" surface reflects more radiation. When a track has cooled, the maximum value of the adjacent track to be cured is preferably closer to the previously cured track than when the track is still hot and already contains more energy, so that only less new energy needs to be introduced.

[0115] In order to operate the production equipment or the irradiation device in a desired manner, in order to obtain such a combined energy beam with a desired overall intensity distribution, corresponding control data can be generated in advance. However, the control data can also be modified dynamically during the process.

[0116] For this purpose, the optimum intensity distribution can preferably be calculated in advance based on the respective position of the irradiated surface in the component and / or other current process parameters. For example, the intensity distribution and other parameters can be optimized and determined, i.e., when the device is controlled using the control data, the building material is melted in a target area in or around the irradiated surface as a heat conduction weld.

[0117] Other process parameters may include, for example, the absolute beam intensity, the speed of movement of the irradiated surface on the construction area, i.e. the scanning speed, as well as the layer thickness and the precise irradiation strategy, i.e., the model in which the irradiation is performed. Various other parameters may also be taken into account, in particular the material characteristic values ​​of the building material, and specific optimization criteria and / or auxiliary conditions and / or boundary conditions may be determined, from which the optimal local target temperature distribution and the optimal total intensity distribution in the target area where the building material is to be melted are calculated, from which control data for controlling the irradiation device and / or other components of the manufacturing device for additive manufacturing are then generated and used in the manufacturing process. Here, the "target area" is understood to be the irradiation surface, i.e., the area on the surface where the energy beam irradiates, but also the area below it, i.e., the area in the depth of the material or layer, but also, if necessary, the environment around the irradiation surface, where, for example, the energy beam acts by heat conduction in the building material.

[0118] Preferably, the total intensity distribution of the combined energy beam is monitored or controlled. Particularly preferably, the data acquired in the monitoring or control are used to adjust the total intensity distribution, for example as an actual intensity distribution which can be compared with a theoretical intensity distribution.

[0119] Therefore, the irradiation device preferably has a suitable monitoring or control device (also referred to below as “monitoring device”).

[0120] Such a monitoring device can be realized, for example, by means of a beam splitter arranged in the optical path of the combined energy beam, which for example branches a small part of the intensity of the combined energy beam into a monitoring unit to measure and check the total intensity distribution of the combined energy beam. The monitoring unit can detect an integrated image / signal of the total intensity distribution, for example, by means of an area sensor or the like.

[0121] For this purpose, the “exposure time” of the area sensor is preferably adapted to the integration period defined above and / or incomplete exposure of the sensor (at least one complete rotation of the second energy beam and interruptions of one or more further revolutions) is compensated by filters, for example evaluation algorithms.

[0122] In monitoring or surveillance of the total intensity distribution, for example, an actual rotation of the total intensity distribution can be compared with a theoretical rotation of the total intensity distribution and / or the actual distribution can be compared with the theoretical distribution. The corresponding actual settings can be fine-tuned, if necessary, by means of additional control loops. BRIEF DESCRIPTION OF THE DRAWINGS

[0123] The present invention will be described in detail again according to the embodiments with reference to the accompanying drawings. Here, the same reference numerals are used for the same components in different drawings. It is shown in the drawings:

[0124] Figure 1A schematic partial cross-sectional view of an embodiment of an apparatus for additive manufacturing is shown, the apparatus having an energy beam modification device according to the present invention,

[0125] Figure 2 A perspective view showing an embodiment of a preferred total intensity distribution of a combined energy beam,

[0126] Figure 3 It shows the cross section along the cutting plane B through the Figure 2 The longitudinal section of the total intensity distribution,

[0127] Figure 4 A schematic diagram showing the functional arrangement of components of a first embodiment of an irradiation device according to the present invention,

[0128] Figure 5 A schematic diagram showing the functional arrangement of components of a second embodiment of an irradiation device according to the present invention,

[0129] Figure 6 A schematic diagram showing the functional arrangement of components of a third embodiment of an irradiation device according to the present invention,

[0130] Figure 6a Shown according to Figure 6 An enlarged schematic diagram of a first energy beam motion unit of an irradiation device,

[0131] Figure 7 shows a schematic diagram of possible control signals for controlling a second energy beam source in an irradiation device,

[0132] Figure 8 Shown with Figure 2 3D images of the total intensity distribution of the same combined energy beam in FIG. 1 , but comparing them in three different embodiments to show the difference between the total intensity distribution and the intensity distribution according to FIG. Figure 5 The correlation of the control signal,

[0133] Fig. 9 Shown in Figure 7 The grayscale image of the total intensity distribution of the combined energy beam on the irradiated surface is shown on the right side of the figure.

[0134] Fig.10 A schematic diagram showing the modification of the total intensity distribution of the combined energy beam according to the irradiation surface environment parameters,

[0135] Fig.11 Another schematic diagram showing the modification of the total intensity distribution of the combined energy beam according to the irradiation surface environment parameters,

[0136] Figures 12a to 12e The three-dimensional diagrams respectively show the total intensity distribution according to different exemplary embodiments of the combined energy beam. DETAILED DESCRIPTION

[0137] The following embodiments are described below with reference to a device 1 for additive manufacturing of manufactured products in the form of a laser sintering or laser melting device 1, wherein it is emphasized again that the invention is not limited to laser sintering or laser melting devices. Therefore, in the following, without limiting the generality, it is referred to as "laser sintering device 1".

[0138] This laser sintering device 1 is Figure 1 Schematically shown in FIG. The device has a process chamber 3 or process chamber 3 with a chamber wall 4, in which the manufacturing process is essentially completed. A container 5 with a container wall 6 that is open upwards is located in the process chamber 3. The upper opening of the container 5 forms the respective current working plane 7. The area of ​​the working plane 7 located within the opening of the container 5 can be used to build the object 2 and is therefore called the construction area 8.

[0139] The container 5 has a base plate 11 which is movable in a vertical direction V and is arranged on a carrier 10. The base plate 11 closes the container 5 downward and thus forms the bottom of the container. The base plate 11 can be formed integrally with the carrier, but it can also be a plate formed separately from the carrier 10 and fixed to the carrier 10 and simply supported on the carrier. Depending on the specific building material, i.e., for example, the type of powder used and the type of production process, a building platform 12 can be placed on the base plate 11 as a building basis, 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 building basis.

[0140] The basic construction of the object 2 is carried out by first placing a layer of building material 13 on the building platform 12, then, as described below, selectively curing the building material 13 by irradiating it with laser light at points that may be parts of the object 2 to be manufactured, then lowering the base plate 11 and the building platform 12 by means of the carrier 10 and applying a new layer of building material 13, which is then selectively cured. This process is repeated until all layers of at least one object are cured. Figure 1 The object 2 built on the building platform 12 in the container is shown in an intermediate state below the working plane 7. The object already has a plurality of solidified layers and is surrounded by unsolidified remaining building material 13. Different materials can be used as building material 13, preferably powders, in particular metal powders, plastic powders, ceramic powders, sand, filled or mixed powders or pasty materials.

[0141] Powdered building material 13 is located in a storage container 14 of the laser sintering device 1. By means of a coating machine 16 movable in a horizontal direction H, the building material can be applied in the form of a thin layer in the working plane 7 or in the building region 8.

[0142] Optionally, there is an additional radiation heating device 17 in the process chamber 3. The radiation heating device 17 can be used to heat the applied building material 13 so that the irradiation device for selective curing does not need to introduce too much energy. That is, for example, a large amount of basic energy can be introduced into the building material 13 by means of the radiation heating device 17, which is naturally lower than the energy required to sinter or even melt the building material 13. For example, infrared radiators can be used as radiation heating devices 17.

[0143] For selective solidification, the laser sintering device 1 has an irradiation device 20 or, in particular, an exposure device 20. The irradiation device 20 generates a combined energy beam AL (or also referred to as a combined laser beam AL below) as an output laser beam AL by combining two energy beams EL1 and EL2 and moving the energy beams EL1 and EL2 relative to each other by means of a first energy beam movement unit 30. The combined energy beam has a defined modified total intensity distribution GIV (see, for example, Figure 2 ), which will be described in detail below.

[0144] The combined energy beam AL is then deflected by a subsequent second energy beam movement unit 23 (also referred to as a reversing unit 23 or scanner 23), thereby opening an exposure path or track set according to the exposure strategy in the layer that needs to be selectively cured and selectively introducing energy. That is, the irradiation surface AF of the combined energy beam AL is moved on the construction area 8 by means of the scanner 23, wherein the current movement vector or movement direction S (scanning direction) of the irradiation surface AF can be frequently and rapidly changed on the construction area 8. Here, the laser beam AL is focused on the working plane 7 in a suitable manner by the focusing device 24.

[0145] Specifically, the irradiation device 20 comprises an energy beam source system 21 or a laser system 21 for generating a first laser beam EL1 and a second laser beam EL2 by means of two separate lasers 21a and 21b. The irradiation device 20 has a first energy beam movement unit 30 and an energy beam combination device 22 downstream of the laser 21b for the second laser beam EL2, which moves the second laser beam EL2 relative to the first laser beam EL1. The energy beam combination device is configured and arranged relative to the scanner 23 so that the first laser beam EL1 and the second laser beam EL2 are coupled into the scanner 23 in a common optical path so that they move together as a combined energy beam AL on the material 13 or the construction area 8. For the construction details of the irradiation device 20, refer to Figure 4 and Figure 5 and their corresponding descriptions.

[0146] Preferably, the lasers 21a, 21b can be gas lasers or solid-state lasers or any other type of laser, for example laser diodes, in particular VCSELs (Vertical Cavity Surface Emitting Lasers) or VECSELs (Vertical External Cavity Surface Emitting Lasers) or an array of such lasers. Very particularly preferably, one or more single-mode lasers can be used in the present invention, for example fiber lasers with a power of 3 kW and a wavelength of 1070 nm. The lasers 21a, 21b for the first laser beam EL1 and the second laser beam EL2 can be constructed identically, but can also be constructed differently.

[0147] The irradiation device 20 is preferably situated outside the process chamber 3 and the combined laser beam AL is introduced into the process chamber 3 via a coupling window 25 which is installed in the chamber wall 4 at the top side of the process chamber 3 .

[0148] The laser sintering device 1 also includes a sensor component 18, which is suitable for detecting process radiation emitted in the working plane during the irradiation of the laser beam 22 onto the building material. The sensor component 18 operates in a position-resolved manner, i.e. the sensor component is able to detect an emission image of the corresponding layer. Preferably, an image sensor or a camera 18 that is sufficiently sensitive in the area of ​​the emitted radiation is used as the sensor component 18. Alternatively or additionally, one or more sensors that detect electromagnetic, in particular optical and / or thermal process radiation can also be used, such as a photodiode that detects electromagnetic radiation emitted by the molten pool under the incident laser beam AL or a thermistor for detecting emitted thermal radiation. It is possible to correspond the signals of sensors that are not position-resolved per se to coordinates, so that the coordinates used to control the laser beam correspond to the sensor signals in time. Figure 1 The sensor arrangement 18 is arranged within the process chamber 3 . However, the sensor arrangement can also be located outside the process chamber 3 and in this case detect the process radiation through another window in the process chamber 3 .

[0149] The signals detected by the sensor arrangement 18 are transmitted as process chamber sensor data sets or grayscale images SB to a control device 50 of the laser sintering device 1 , which also serves to actuate the various components of the laser sintering device 1 for controlling the additive manufacturing process as a whole.

[0150] To this end, the control device 50 has a control unit 51, which controls the components of the irradiation device 20 via the irradiation control port 53, namely, sending laser control data LSa to the lasers 21a, 21b, sending relative motion control data RS to the first energy beam motion unit 30, sending scanning control data SD to the second energy beam motion unit 23 or the scanner 23 and sending focusing control data FS to the focusing device 24.

[0151] The control unit 51 also controls the radiation heater 17 by means of suitable heating control data HS, the coating machine 16 by means of coating control data ST and the movement of the carrier 10 by means of carrier control data TS.

[0152] In addition, the control device 50 has a quality data determination device 52 which receives the process chamber sensor data set SB and determines quality data QD based thereon, which can be forwarded to the control unit 51 for adjustable intervention in the additive manufacturing process, for example.

[0153] The control device 50 is coupled here, for example, via a bus 55 or another data connection to a terminal 56 having a display etc. An operator can control the control device 50 and the entire laser sintering device 1 via the terminal 56, for example by transmitting process control data PST.

[0154] In order to set up the production process in a desired manner, the control data can be generated or modified accordingly by means of the control data generating device 54 , 54 ′.

[0155] The control data generating device 54 can be, for example, a part of the control device 50 and can be implemented in the form of a software part. Such a control data generating device 54 integrated in the control device 50 can also receive and modify the existing process control data PSD, and can then transmit the corresponding modified control data PSD to the control unit 51. Here, the modified control data PSD can include in particular modified laser control data LSa, LSb, but if necessary also include other modified control data, such as changed coating control data ST or carrier control data TS, in order to select a suitable layer thickness. Alternatively, however, it is also possible to modify only the laser control data LSa, LSb in the control data generating device 54 and forward it to the control unit 51, so that the irradiation control port 53 works with the modified laser control data LSa, LSb.

[0156] However, it is also possible that the control data generation device 54' is implemented on an external computer unit, for example, here on the terminal 56, and has previously created process control data PSD with correspondingly suitable exposure control data, with the aid of which the device 1 is controlled so that, for example, a desired intensity distribution is achieved. In this case, the internal control data generation device 54 present here in the control device 50 can also be omitted.

[0157] As described, the process control data PSD generated or modified by the control data generating device 54, 54' can also be regarded as setpoint values, which are then used in the control unit 51 for regulating the process, wherein, for example (as a possibility) the quality data QD can also be taken into account as actual values.

[0158] It should also be emphasized here again that the present invention is not limited to such a laser sintering device 1. The laser sintering device can be used in particular for any other method for generating or additively manufacturing three-dimensional objects by applying and selectively solidifying a building material, in particular layer by layer, wherein an energy beam is output to the building material to be solidified for solidification. The laser sintering device can also be used for welding welds or for other processes in which a material can be irradiated with an energy beam, in particular for locally melting the material. The irradiation device can therefore be not only a laser as described here, but also any device that can selectively bring energy as wave or particle radiation to or into the building material. For example, instead of a laser, another light source, an electron beam, etc. can be used. It is also possible to generate and use a plurality of combined energy beams according to the invention in parallel, so that, for example, selective solidification can be carried out at a plurality of locations on the construction area at the same time.

[0159] Even in Figure 1 Only a single object 2 is shown in FIG. 1 , but a plurality of objects can and usually are produced in parallel in a process chamber 3 or container 5 . For this purpose, the building material is scanned layer by layer by an energy beam at locations corresponding to the cross section of the object in the individual layers.

[0160] Figure 2 The typical basic shape of the total intensity distribution GIV of the combined energy beam AL is shown, which is particularly suitable for this shape or slightly different shapes (see also the Figure 2 and Figure 7 ), so that in the process area of ​​heat conduction welding the melting process of the material 13 in the area of ​​the irradiation surface AF of the combined energy beam AL on the construction area 8 is maintained, that is, no vapor capillary phenomenon occurs when melting the construction material.

[0161] In this regard, Figure 2The total intensity distribution (hereinafter also referred to as intensity distribution GIV) in a plane x, y perpendicular to the beam axis SA of the combined energy beam AL (hereinafter mostly referred to as energy beam AL) is shown, wherein the intensity in the z direction is plotted in a spatially resolved manner on the plane x, y. Depending on the angle of incidence of the energy beam AL on the construction zone 8, slight distortions may occur, but in principle these can be compensated by correspondingly controlling the individual components when generating the energy beam AL, if this is necessary and / or desired.

[0162] In the middle region of the total intensity distribution GIV, i.e. here within approximately half the radius up to the edge R of the intensity distribution GIV (the edge is defined above, for example, as 99% of the radiation power within the edge R), there is an intensity minimum MIZ (hereinafter also referred to as "minimum") . This minimum MIZ is located approximately in the center of the intensity distribution GIV, i.e. approximately on the beam axis SA of the energy beam or on the axis of the beam path.

[0163] In the edge region around this central region, i.e. along the intensity profile IPK within the edge R but surrounding this edge, there is a local intensity maximum MAX (hereinafter also referred to as "maximum") and a diagonally opposite local intensity minimum MIN (hereinafter also referred to as "minimum") with respect to this intensity profile IPK on one side. "Local" is here respectively understood to be a function of the intensity value with respect to the position along the intensity profile IPK, which is located parallel to the edge R or centrally on the surrounding circular track K.

[0164] The intensity values ​​along the circular track K on this intensity profile IPK start from an intensity maximum MAX and converge continuously on both sides, i.e. in both directions of rotation, to an intensity minimum MIN, i.e. the intensity values ​​decrease (here continuously) until this point. Depending on the type of signal generation, the signal may also be subject to so-called "ringing" or other influences, such as digitization levels, which may appear in the intensity profile in the form of noise, harmonics or other artifacts. The intensity distribution GIV is here arranged such that the maximum MAX is located at the front on the intensity profile IPK in the scanning direction S (here arbitrarily parallel to the x direction of the plane) and the minimum MIN is located at the rear.

[0165] Figure 3 A longitudinal section through the total intensity distribution GIV is shown in a section plane B extending in the scanning direction S (ie in the x / z direction). Figure 2 Draw in. Figure 2 For the sake of clarity, the section plane B is shown in a simplified manner. Figure 3 The same longitudinal section.

[0166] Here, the maximum value MAX is clearly visible at the front and the minimum value MIN is clearly visible at the rear along the scanning direction S, but the minimum value is relatively small relative to its value along the scanning direction S. Figure 3 A local maximum is again formed around the longitudinal section in , since the intensity of the intensity distribution GIV decreases rapidly outwards to the edge R and has a minimum MIZ towards the middle, ie towards the center.

[0167] In order to illustrate the advantageous effect of the intensity distribution GIV on setting a specific target temperature in the region of the irradiated surface on the construction zone 8, in which the melting process can be maintained within the process window of thermal welding, the intensity distribution GIV is virtually divided into three functional regions F1, F2, F3 (see Figure 3 ). The total intensity distribution GIV primarily determines the "region of action", which can be limited, for example, by the edge R of the intensity distribution GIV, but can also extend beyond it. These can be defined as follows:

[0168] The total intensity distribution GIV relates to the irradiation surface, which moves over the construction area 8, as has been described several times above. At least in a sub-region of the irradiation surface AF of the combined energy beam AL, melting of the construction material 13 is caused. In order to achieve the process window of heat conduction welding as far as possible in the melting region, the total intensity distribution GIV must be set so that it meets the different tasks.

[0169] The following description assumes that the observer moves together with the irradiation surface AF. From the observer's perspective, at each point in time, new material 13 is transported into the irradiation surface AF during the movement of the irradiation surface AF over the construction zone 8. This construction material 13 is usually cooler than the molten bath. Therefore, the construction material 13 must first be heated. This task is taken over by the first functional area F2 "heating", which usually has the highest intensity among all the different functional areas F1, F2, F3 of the intensity distribution GIV. This is Figure 3 , correspondingly, the front region with the absolute maximum MAX of the intensity distribution GIV. This front region is represented everywhere where the intensity distribution GIV first encounters unsolidified building material or building material that has solidified in a previous irradiation or melting process when moving over the building material.

[0170] At the edge of the irradiation surface AF, heat is transported into the surrounding building material 13, in particular by conduction. This loss should preferably be compensated. In the preferred intensity distribution GIV, this compensation is achieved by the functional region F1 “holding”. The functional region F1 “holding” forms a kind of (lateral in top view) edge of the total intensity distribution GIV and is Figure 2 and Figure 3 In other words, this is a circular region of increased intensity that surrounds the edge R within the edge on the intensity curve IPK.

[0171] This functional region F1 “holds” transitions to the functional region F2 “heats” in the region located in front in the scanning direction S. Since the building material 13 should be hardened locally after passing the irradiation surface AF on the building field 8, it is advantageous if the minimum value MIN in the intensity curve IPK in the functional region F1 “holds” is located in the region located in the rear in the scanning direction S.

[0172] The area of ​​the total intensity distribution GIV surrounded by the functional areas F1, F2 "holding" and "heating" has the task of setting and thus controlling the temperature profile in the active area, i.e. in the melt, so that, for example, the desired process range of heat conduction welding can be maintained. This is achieved by the functional area F3 "shaping".

[0173] The transition between the functional regions F1, F2, F3 is continuous, wherein the functional regions F1, F2, F3 can overlap or superimpose in several regions. As can be seen here, the intensity distribution GIV is essentially a (flat) convex function in the "shaping" of the functional region F3, while the cross-sections of the other functional regions F1, F2 have a concave function curve.

[0174] Such a preferred total intensity distribution GIV can be achieved, as described above, by a combined energy beam AL which is generated by superposition of two energy beams EL1 , EL2 , wherein the energy beam EL2 moves at a high speed value relative to the first energy beam EL1 at a scanning speed value.

[0175] exist Figure 2 and Figure 3 The (total) intensity distribution shown in can be achieved specifically in the following manner, generating a first energy beam EL1 having a first intensity distribution SP1, which corresponds to a so-called top-hat intensity distribution SP1 and substantially overlaps with a Gaussian second intensity distribution SP2 of the second energy beam EL2 which is circumscribed on a circular track K along an edge R of the intensity distribution SP1 of the first energy beam EL1. Here, the beam spread of the intensity distribution SP2 of the second energy beam EL2, here the diameter, is significantly smaller than the beam spread DS, here the diameter DS, of the intensity distribution SP1 of the first energy beam EL1. For example, the first energy beam EL1 may have a diameter of approximately 1000 μm and the second energy beam EL2 may have a diameter of approximately 80 μm. For this purpose, the top-hat beam EL1 provides a “basic intensity” on the irradiation surface AF. With the aid of the Gaussian beam EL2 moving on a circular track K around the center of the top-hat beam, the irradiation of the first energy beam EL1 is achieved. Figure 2 and Figure 3 The local intensity increase LIE (ie confined to a region along the circular track K) along the edge R of the overall intensity distribution GIV can be clearly seen in FIG.

[0176] For this purpose, the second smaller energy beam EL2 is circulated at high speed (relative to the scanning speed) on a circular trajectory K, so that the irradiated surface AF on the construction area 8 is subjected to a total intensity distribution GIV by time integration (as described over a time period of a certain duration, for example over a cycle), as in Figure 2 and Figure 3 as shown in .

[0177] In order for the intensity on the intensity curve IPK in the scanning direction S to have a maximum value MAX in the front and a minimum value MIN in the rear region and to decrease or increase continuously therebetween, the intensity of the second energy beam EL2 must be modulated synchronously with the rotational speed.

[0178] In addition, in principle, one or each of the functional regions F1, F2, F3 can also be configured as a plateau, so that the intensity distribution along the boundaries between the functional regions F1, F2, F3 is, for example, stepped. Figure 2 and Figure 3 As shown in , the design of the intensity distribution by means of a curved intensity profile or as a combination of superpositions of different intensity profiles can generally be realized technically more simply and cost-effectively.

[0179] according to Figures 4 to 6 An example is described in which such a combined energy beam AL can be generated in a particularly simple and cost-effective manner.

[0180] In accordance with Figure 4 In the first embodiment of the invention, the irradiation device 20 has an energy beam source system 21 including two single lasers 21a, 21b. The first laser 21a generates a laser beam EL1 as a first energy beam EL1 and is constructed or provided with a beam shaping device so that the first laser beam EL1 has a desired top-hat intensity distribution. The second laser 21b is constructed so that it generates a laser beam EL2 having a Gaussian-shaped intensity distribution as a second energy beam EL2. Therefore, without being limited to general cases, the terms "laser beam" and "energy beam" are used synonymously below.

[0181] First, the second laser beam EL2 is radiated through the first energy beam movement unit 30, which moves the second laser beam EL2 relative to the first laser beam EL1. The first energy beam movement unit 30 includes a hollow shaft 31, which rotates around a rotation axis Rah at a rotation speed Ω, and the rotation axis corresponds to the longitudinal axis of the hollow shaft 31. In order to drive the hollow shaft 31, a corresponding motor (not shown) is equipped for the hollow shaft.

[0182] The optical path S2 or beam axis S2 of the second laser beam EL2 extends such that the laser beam EL2 enters the hollow shaft 31 directly on the rotation axis RAh. An optical element 32, more precisely a transmitted beam displacement element 32, is arranged in the hollow shaft 31 or at the end of the hollow shaft, which displaces the Gaussian-shaped laser beam 21B laterally by a path or axis distance d relative to the rotation axis RA. In the illustrated embodiment, the transmitted beam displacement element 32 is a plate 32. By rotating the plate 32 on the hollow shaft 31, the Gaussian-shaped second laser beam EL2 or its beam axis S2 always moves parallel to the rotation axis RAh, but on a circular orbit extending around the rotation axis RAh at an axis distance d. By integrating over a circumference on the circular orbit, the (virtual) "average beam axis" or "average beam optical path" of the second laser beam EL2 defined as above lies exactly on the rotation axis RAh.

[0183] The rotating second energy beam EL2 is then combined with the first energy beam EL1 in the beam combiner 22 of the energy beam combining device 22, in this polarizer 22 (for example, a thin-layer polarizer 22), wherein it is to be noted that the virtual rotation axis RAv around which the second energy beam EL2 rotates, i.e., the “average beam axis” of the second laser beam EL2, extends coaxially with the beam axis S1 of the first energy beam EL1 after the beam combiner 22.

[0184] Finally, the axial distance d by which the beam axis S2 of the second energy beam EL2 is displaced relative to the rotation axis RA determines the radius of the intensity variation curve around the beam axis SA in the total intensity distribution GIV of the combined energy beam AL, i.e., the radius of the circular orbit K. Here, the axial distance d is the distance between the virtual rotation axis RAv of the second energy beam EL2 and the center of the second intensity distribution SP2, where the diameter of the total intensity distribution GIV is slightly larger than twice the axial distance d.

[0185] Since the optical path S1 of the first laser beam EL1 and the “average optical path” of the second energy beam EL2 extend coaxially, the two laser beams EL1 and EL2 are coupled into the scanner 23 on a common optical path, for example, on the first scanning mirror of the scanner. Therefore, the laser beams EL1 and EL2 are superimposed on each other and move on the material 13 as a combined energy beam AL at the irradiation surface AF on the structure area 8 at a scanning speed and scanning direction preset by the scanner 23. Here, the scanning motion itself has no effect on the relative movement of the second energy beam EL2 within the combined energy beam AL. However, it may be advantageous to change the movement of the second laser beam EL2 relative to the first laser beam EL1, for example, the movement speed or the intensity modulation of the second laser beam EL2, according to the scanning motion, that is, the scanning direction and / or the scanning speed.

[0186] exist Figure 5 Another embodiment of the irradiation device 20 is shown in FIG. Figure 4 In the embodiment of the present invention, a corresponding combined energy beam or combined laser beam AL can be generated by means of an irradiation device. In this embodiment, the irradiation device 20 also has an energy beam source system 21, which has two independent lasers 21a, 21b, which are used for the first energy beam or laser beam EL1 and the second energy beam or laser beam EL2. Here, a first laser beam EL1 with a top hat intensity distribution is generated and directly transmitted to a beam combiner 22.

[0187] However, in this case, the first energy beam movement unit 33 is connected to the Figure 4 The energy beam movement unit 33 comprises a first reflector 34 , a further reflector 35 which rotates during operation, and a focusing lens 37 as optical elements.

[0188] First, the (still) Gaussian-shaped second laser beam EL2 is incident on the first mirror 34 and is guided from there to the rotating mirror 35, which is inclined to the (entry) beam path S2 of the incident second laser beam EL2, wherein the rotation axis RAs of the mirror 35 runs coaxially with the beam path S2 of the incoming laser beam EL2. The rotating mirror 35 is driven by an electric motor 36, which can be controlled in a suitable manner by the control device 50. Since the rotational movement of the mirror 35 causes a corresponding movement of the mirror surface or the mirror plane due to the inclined arrangement of the mirror plane SE, the beam path S2 of the second laser beam EL2 is deflected, and the beam path S2 first moves on the cone surface starting from the mirror 35, and the radius of the circular path increases with increasing distance from the rotating mirror 35. In other words, the beam path S2 of the second laser beam EL2 starting from the rotating mirror 35 is tilted by an angle relative to the rotation axis RAs of the mirror 35.

[0189] As in Figure 5 As shown in FIG, a converging lens 37 is arranged as an optical element in another optical path after the rotating reflector 35. The converging lens is located after the first reflector 34 along the rotation axis RAs in the beam propagation direction starting from the rotating reflector 35. The running angle of the optical path starting from the reflector 35 and the spacing between the components 34, 35, 37 and their dimensions are selected so that the optical path S2 passes by the first reflector 34 in each rotation position and impinges on the converging lens 37.

[0190] The converging lens 37 is oriented here so that its optical axis is coaxial with the rotation axis RA of the rotating reflector 35. Preferably, the converging lens 37 is designed so that the outgoing beam of the laser beam that crosses the converging lens in a specific direction runs parallel to the rotation axis RA. As a result, the converging lens deflects or orients the incoming second laser beam EL2 that moves in the shape of a cone surface on the track again so that the optical path S2 of the second laser beam EL2 runs parallel to and radially offset from the (imaginary extended) rotation axis RAs (i.e., the virtual rotation axis RAv) at a fixed axis spacing d during the further operation after the converging lens 37.

[0191] In this configuration, the axis distance d and the radius of the circular orbit of the second laser beam EL2 around the axis of rotation RA can be set by changing the distance between the converging lens 37 and the rotating mirror 35 and / or the tilting position of the rotating lens 35. In the case of a change in the distance during operation of the irradiation device 20, the converging lens 37 must be supplemented with an optical unit to adjust its focus. This is the focus of the converging lens 37 on the side of the converging lens 37 facing the rotatable mirror 35 (i.e., the input side). During the use of the irradiation device 20 for curing the building material, the focus of the converging lens 37 (within the normal tolerance range) is preferably always located in the mirror plane of the rotating mirror 35 and here at its center of rotation.

[0192] In this embodiment, the (virtual) "average beam axis" or "average optical path" of the second laser beam EL2 about one cycle of the circular orbit is located exactly on the rotation axis of the reflector, because the rotation axis corresponds to the virtual rotation axis RAv about which the second laser beam EL2 rotates. The virtual rotation axis RAv of the second laser beam EL2 as well as the "average beam axis" and the optical path S1 of the first energy beam EL1 are also oriented here so that they impinge on the beam combiner 22 of the energy beam combining device 22, so that the virtual optical path of the second energy beam EL2, which is periodically averaged according to the above definition, is coaxial with the optical path S2 of the first energy beam EL1 and the optical path S2 of the second energy beam EL2 rotates in parallel around the optical path S1 of the first energy beam EL1 at an axial spacing d. As in accordance with Figure 4 In the embodiment of the present invention, the combined energy beam AL thus generated can now be coupled into the scanner 23.

[0193] Figure 6 and Figure 6a Another variant is shown, in which Figure 6a The enlarged view shows Figure 6 The first energy beam motion unit 33' in the embodiment of the present invention is used to describe the angular position in more detail. Figure 5However, the first energy beam movement unit 33' is configured to eliminate the first reflector 34. Instead, the rotation axis Rar of the rotating reflector 35' (and the electric motor 36') is not as in the embodiment according to Figure 5 In the embodiment of FIG. 3 , the lens 37 is arranged coaxially with the optical axis of the converging lens 37 ′, but at an angle of 45° thereto.

[0194] The mirror plane SE of the rotating mirror 35' is also tilted at an angle α relative to the perpendicular to the rotation axis RAs of the mirror 35'. In other words, the periodically averaged (virtual) mirror plane according to the above definition rotates at an angle α around the rotation center RZ of the mirror 35' as the rotation point. The rotation or tilt position can be fixed, the rotation axis RAs of the mirror 35' being fixed. Alternatively, the rotation or tilt position can be variable, the mirror 35 and its rotation axis RAs being mechanically connected to each other, for example, by a hinge, wherein the hinge can be adjusted by an electric motor.

[0195] If, as shown, the second laser beam EL2 of the second laser 21b is radiated at 90° to the optical axis of the convergent lens 37 and at 45° to the rotation axis RA of the rotating mirror 35 onto the rotation center RZ of the rotating mirror 35', the second laser beam is transmitted from there to the convergent lens 37' at an angle of 2α to the optical axis of the convergent lens 37'. Since the rotational movement of the mirror 35' causes the mirror surface or the mirror plane SE to move accordingly due to the tilted arrangement of the mirror plane SE at the angle α, the second laser beam EL2 here first moves on the cone surface starting from the mirror 35' and is deflected or directed again by the convergent lens 37' so that the beam path S2 of the second laser beam EL2 runs parallel to the optical axis of the convergent lens 37' in the further operation after the convergent lens 37'. For this purpose, the input-side focus or focal point of the convergent lens 37' is located on the mirror plane SE and in the rotation center RZ of the reflector 35'.

[0196] In this embodiment, by changing the tilt position of the rotating reflector 35' (i.e., at an angle α±x), the axis distance d and the radius d of the circular orbit around the optical axis of the converging lens 37 generated by the rotational movement of the second laser beam EL2 (i.e., the "virtual rotation axis" RAv around which the second laser beam EL2 rotates) can be set. If the converging lens 37' is constructed or its focal length f is selected so that its input-side focus is located on the reflector average SE and in its rotation center RZ even when the second energy beam reflected by the reflector 35' has a large or small deflection, and its output-side focus is in an infinite position, the above requirements for the optical path of the second laser beam EL2 are met, so that the possible optical paths of the two emitted laser beams EL2 extend parallel to each other.

[0197] In accordance with Figure 5 and Figure 6 (as well as Figure 6a ) in the embodiment, all other components may be constructed and arranged identically.

[0198] In all three drawings Figures 4 to 6 The irradiation devices 20 shown in each case comprise a monitoring device 26. For this purpose, a beam splitter 27 is introduced in each case in the beam path, which branches a small part of the intensity of the combined energy beam AL to a monitoring system 28 for measuring and checking the total intensity distribution GIV of the combined energy beam AL. The monitoring system 28 may comprise a surface sensor, which records an overall image / signal of the total intensity GIV. Thus, for example, in the monitoring system 28 or in the control device 50, for example, the actual rotation of the total intensity distribution GIV can be compared with the theoretical rotation and / or the actual distribution with the theoretical distribution of the intensity distribution, and the corresponding actual position can be fine-tuned if necessary with the help of an additional control circuit (not shown).

[0199] In all the embodiments described in detail above, the rotation speed Ω is selected such that the value of the orbital speed of the movement on the circular orbit K in the total intensity distribution GIV of the two combined energy beams AL of the second energy beam EL is high relative to the corresponding scanning speed S.

[0200] In order to achieve an intensity maximum MAX and an intensity minimum MIN at the edge R of the top hat distribution on the intensity variation curve IPK along the circular track K, the intensity of the second energy beam EL2 can be modulated during its movement on the circumference of the circular track. Figures 4 to 6 In the simplest case, the power L of the second laser 21b can be modulated by means of the generator signal GS, as in Figure 7 as shown in .

[0201] For simplicity, here we use the polar angle on the circular orbit Describes the modulation, where Figure 7 The amplitude A of the generator signal GS, which is related to the power to be output by the second laser 21b and the absolute intensity of the second laser beam, is plotted in arbitrary units on the angular On (the angle is Figure 6 In the angle Here the generator signal GS has its maximum amplitude and is directed towards the angle The absolute intensity of the second laser beam EL2 with a Gaussian shape changes sinusoidally between the minimum value and the maximum value during its rotation on the circular track K. In front along the scanning direction S. Therefore, the intensity maximum MAX of the total intensity distribution GIV is located in the front along the scanning direction S and the intensity minimum MIN is located in the back, as in Figure 2 and Figure 3 as shown in .

[0202] By simply phase shifting the generator signal GS, the maximum value MAX and the minimum value MIN can be moved on a circular track K, i.e. around the center of rotation of the top hat intensity distribution or the beam axis S1. This is important on the one hand when changing the scanning direction over the structure area, but it is also important to adapt the position of the total intensity distribution GIV or the maximum value MAX to the ambient parameters of the current impact point AF, if necessary.

[0203] By, for example, Figure 7 The amplitude A of the generator signal GS for the second laser beam EL2 shown in FIG. 1 can set the relative intensity difference between the maximum value MAX and the minimum value MIN on the intensity curve IPK. This is for example Figure 8 1 shows three total intensity distributions GIV shown next to each other, wherein all total intensity distributions GIV have the same basic shape and differ only in the size of the maximum and minimum values ​​or in the shape of the intensity variation along the circular trajectory K along the edge of the total intensity distribution GIV on the intensity variation curve IPK. That is, the basic shape of the total intensity distribution GIV is distorted, wherein the minimum MIZ is shifted backwards within the total intensity distribution GIV in a direction opposite to or opposite to the scanning direction.

[0204] Which specific shape of the total intensity distribution GIV is optimal for the current manufacturing process may depend on various other process parameters, in particular on the current scanning speed.

[0205] Figure 8 The modulation of the total intensity distribution GIV at a scanning speed of 0.1 m / s is shown on the left, for example. The total intensity distribution GIV at a scanning speed of 1.6 m / s is shown in the middle. The total intensity distribution GIV at a scanning speed of 3.1 m / s is shown on the right.

[0206] In the comparison of the three total intensity distributions GIV, it can be seen that with increasing scanning speed, the maximum value MAX rises relative to the minimum value MIN on the intensity curve IPK. In other words, the functional area F2 is "heated" (see Figure 2The functional area F1 "hold" is increased in a particularly limited manner relative to the functional area "hold" F1. This can be explained simply in the following way: the functional area F1 "hold" is used only as a "heat loss compensation area" to compensate losses by heat flow within the temperature difference between the molten bath and the surrounding material. In other words, the expansion of the functional area F1 "hold" can be proportional to the material values, in particular the thermal conductivity, the thermocapillary convection and the temperature distribution in the vicinity of the molten bath. However, in particular with increasing speed, this functional area F1 "hold" is no longer important compared to the other defined functional areas.

[0207] The "heating" of the functional area F2 is used to preheat or heat the cold building material 13 that has not yet solidified or the partially solidified material of the adjacent track (for example, the adjacent filling part) to the melting temperature. In particular, this area changes with the speed of the irradiated surface. As the scanning speed increases, the heating must be correspondingly faster, that is, a greater intensity is required and the maximum value is higher and therefore the functional area F2 is wider, that is, the width of the functional area F2 extends outward beyond the center of the total intensity distribution GIV. In extreme cases (see Figure 8 The minimum value MIN of the curve IPK also corresponds to the absolute minimum value MIN of the total intensity distribution GIV. Figure 8 , it can be seen that the total intensity distribution GIV has a local minimum in the middle region with reference to the secant SK, since the second laser beam EL2 locally increases the total intensity distribution GIV on the intensity profile IPK. The secant SK runs perpendicularly to the scanning direction S through the center of gravity of the total intensity distribution GIV (geometrical diagram), which is located here displaced forward in the scanning direction S between the center through which the rotation axis or beam axis SA of the total intensity distribution GIV runs and the maximum value MAX.

[0208] Fig. 9 For this purpose, a grayscale image SB of the intensity distribution of the combined energy beam is shown, for example in FIG. Figure 8 In this case, the bright areas are regions with particularly high energy beam intensities. These regions clearly show a sickle shape or a half-moon shape with a curvature in the direction of the scanning direction S. That is, at the "front edge" of the total intensity distribution GIV, which first impinges on the material during the feed or scanning movement, an intensity significantly higher than the average intensity is measured, which then decreases relatively gently in the rear region and then extends gently and flatly toward the rear edge.

[0209] As mentioned above, for example, in the illustrated embodiment, the Figure 7The generator signal GS shown in φ 21 b controls the second laser 21 b simply with a phase shift, so that the maximum value MAX and the minimum value MIN are shifted on the intensity curve IPK, ie the total intensity distribution GIV rotates about the center of rotation or beam axis SA of the total intensity distribution GIV.

[0210] As described, this may be necessary when the direction of the scanning movement changes, for example when the filling section is reversed, and when the shadow line is swept towards the end of the shadow line (filling section) in the radiation strip, the adjacent filling section should be swept in the opposite direction. On the other hand, however, it is also advantageous if the specific design of the total intensity distribution GIV can be adapted to the ambient temperature of the irradiation surface, that is, in particular to whether curing is currently taking place on a track or filling section parallel to an already cured area.

[0211] For this purpose, see for example Fig.10 In the upper figure, four filling tracks HE are shown by way of example, wherein the irradiation area AF currently extends along the scanning direction S along a first track HE, next to which there is an adjacent track which has not yet solidified. The total intensity distribution GIV is therefore preferably oriented such that the maximum value is located exactly in front in the scanning direction S and the minimum value MIN is located behind. In other words, the total intensity distribution GIV is axisymmetric about an axis of symmetry AS which extends parallel to the scanning direction S or coaxially thereto.

[0212] exist Fig.10 The lower area of ​​​​the figure shows the situation during solidification in the subsequent track HE, wherein the immediately preceding track is still warm, but has already hardened. It is advantageous here that the intensity variation curve IPK is slightly rotated relative to the scanning direction S, so that the maximum value MAX is slightly further away from the already solidified area VB of the first track HE and the minimum value MIN is closer to the solidified area VB. In other words, the total intensity distribution GIV is intentionally not axisymmetric about the symmetry axis AS coaxial with the scanning direction S defined above. This is because energy is already introduced into the adjacent filling parts during solidification. Because the solidification of the individual filling parts arranged side by side usually takes place at short time intervals, usually within this time interval, the molten building material has not completely cooled, for example to the ambient temperature in the process chamber or the construction space. In order to connect the current track HE with the recently solidified, respectively adjacent tracks HE, only energy that has not been dissipated by heat conduction into the underlying material is still available. The scanning paths or total intensity distributions shown here are strictly separated and are no larger than a single scanning path. However, superposition is also conceivable in principle.

[0213] If the adjacent track HE has already cooled because it solidified at a relatively large time interval before the current track HE, it may be advantageous to orient the maximum of the total intensity distribution for irradiating the current track in the direction of the already hardened and cooled track or according to Fig.10The above shows a rotation from the output position. Because in this case the heat conduction increases in the area where the track HE to be cured is close to the cured track HE, so a lot of energy must be introduced here to achieve the desired curing. However, this variant is not shown in the separate figures.

[0214] Strategy replacement during solidification of a single track is also possible, as in Fig.11 As shown schematically in FIG.

[0215] For example, when the current track HE is cured in the opposite direction to a relatively long, previously cured adjacent track HE, then at the beginning of the current track HE, the previously cured adjacent region VB is relatively hot, because relatively little time has passed since its curing began. On the other hand, near the end of the track HE, the adjacent cured region VB is always cooler. Therefore, the maximum value MAX can be rotated away from the adjacent cured region VB at the beginning of the current track HE (position P1), i.e. closer to the track HE that is adjacent to the current track and may need to be cured later than at the cured region VB. During the continuation of the irradiation in the scanning direction S, the maximum value MAX of the total intensity distribution rotates so that it is located on the axis of symmetry AS (position P2) and then gradually, preferably continuously, continues to rotate so that it rotates towards the adjacent cured region VB at the end of the current track HE (position P3), i.e. closer to the cured region VB than to the track HE that is adjacent to the current track and may need to be cured later.

[0216] exist Figures 12a to 12e , further possible total intensity distributions are shown, which are generated by a ("smaller") second energy beam running in a circular orbit, wherein the orbit of the second energy beam in each case again runs approximately parallel to the edge of the energy distribution of the ("larger") first energy beam. In each case, the first energy beam has a plateau ("flat-top" or "top-hat intensity distribution"), but with different geometric bases. That is, the intensity distribution is relatively spatially uniform over a beam cross section with relatively sharp edges. This first energy beam with such an energy distribution can also be generated by a suitable beam shaping unit, for example a diffractive optical element (DOE).

[0217] Specifically, Fig.12a The total intensity distribution is shown with a hexagonal or honeycomb-shaped base, wherein one corner is located at the front in the scanning direction S. Figure 12b shows the total intensity distribution with a quadrilateral base, wherein one corner is located at the front in the scanning direction S. Fig.12c The quadrilateral base area of ​​the total intensity distribution is oriented in such a way that one edge of the quadrilateral (here a square) is located in the front in the scanning direction S. Fig.12d and Fig.12eTwo triangular variants are shown, one with the front edge perpendicular to the scanning direction S ( Fig.12d ) and one with a tip or corner in front along the scanning direction S ( Fig.12e ).

[0218] In each case, the second energy beam also changes its intensity during its trajectory so that the intensity maximum or the maximum region of the total intensity distribution (with the leading edge in the distribution) lies in the front along the scanning direction S.

[0219] In practice, edges or corners of the geometric diagram of the total intensity distribution which are shown in the figure in an angular manner are also produced in a rounded manner (for example components of a beam generator or a beam deflection device which move due to inertia).

[0220] Finally, it should also be emphasized that the above-described device is only an embodiment that can be modified in different ways by a person skilled in the art without departing from the scope of the invention. In particular, it is pointed out again that a combined energy beam with a suitable total intensity distribution can also be generated in the following way, that is, by means of two scanners that are coordinated or synchronously controlled, the first energy beam and the second energy beam are located in the irradiation surface at any time in a suitable position superimposed on each other, and the scanner of the second energy beam can then be moved faster than the scanner of the first energy beam. For example, in order to move the irradiation surface of the combined energy beam, the irradiation device can also be moved together with at least two radiation sources, one of which is additionally or coincidently relative to the other radiation source (preferably fast) relative movement, or at least one of the energy beams of one of the jointly moving radiation sources is moved relative to the energy beam of the other radiation source with a movement unit provided for this purpose, such as a reflector, etc. It is also possible to use (different) focus changes or expansion / defocusing of the energy beams in addition to the relative movement of the two energy beams to each other. It should also be mentioned that methods other than additive manufacturing can also be used, as well as methods using other processes, such as welding welds, etc. Furthermore, the use of the indefinite article "a" or "an" does not exclude that the feature in question may also be present multiple times. The term "unit" also does not exclude that the unit consists of a plurality of cooperating subcomponents, which may also be spatially distributed.

[0221] Reference numerals list

[0222] 1 Device for additive manufacturing / laser sintering device

[0223] 2. Manufacturing products / objects / components

[0224] 3 Process chamber / cavity

[0225] 4 Cavity wall

[0226] 5. Container

[0227] 6 container wall

[0228] 7 Work Plane

[0229] 8 Tectonic Zone

[0230] 10 Carrier

[0231] 11 base plate

[0232] 12 Construction Platform

[0233] 13. Building Materials

[0234] 14 Storage Containers

[0235] 16 Coating Machine

[0236] 17 Radiant heating device

[0237] 18 Sensor assembly / camera

[0238] 20 Irradiation device / exposure device

[0239] 21 Energy beam source system / laser system

[0240] 21a Laser

[0241] 21b Laser

[0242] 22 Energy beam combiner / beam combiner

[0243] 23 Second energy beam motion unit / scanner / reversing unit

[0244] 24 Focusing device

[0245] 25 Coupling window

[0246] 26 Monitoring Device

[0247] 27 Beam splitter

[0248] 28 Monitoring System

[0249] 30 First Energy Beam Motion Unit

[0250] 31 Hollow shaft

[0251] 32 Optical elements / transmitted beam displacement elements / plates

[0252] 33 First Energy Beam Motion Unit

[0253] 33' First Energy Beam Motion Unit

[0254] 34 First Reflector

[0255] 35 Rotating Mirror

[0256] 35' rotating reflector

[0257] 36 Rotary unit / electric motor

[0258] 36' Swivel Unit / Electric Motor

[0259] 37 Converging lens

[0260] 37' Converging lens

[0261] 50 Control device

[0262] 51 Control unit

[0263] 52 Quality data determination device

[0264] 53 Irradiation control port

[0265] 54 Control data generation device

[0266] 54' Control data generation device

[0267] 55 Bus

[0268] 56 Terminal

[0269] A Amplitude of the generator signal

[0270] AF irradiation surface

[0271] AL (output) combined energy beam / laser beam

[0272] AS Axis of symmetry

[0273] B Cutting plane

[0274] d Axis spacing

[0275] DS Beam expansion (Strahlausdehnung) / diameter

[0276] EL1 First energy beam / laser beam

[0277] EL2 Second energy beam / laser beam

[0278] f Focal length

[0279] FS Focus control data

[0280] F1 Function area "Hold"

[0281] F2 Function area "Heating"

[0282] F3 Functional area "Forming"

[0283] GS Generator Signal

[0284] H Horizontal direction

[0285] HE Hatch-Spuren

[0286] HS Heating Control Data

[0287] GIV Total Intensity Distribution

[0288] IPK strength change curve

[0289] K Circular track

[0290] LIE Local Strength Improvement

[0291] LSa, LSb Laser control data

[0292] MAX Local maximum

[0293] MIN Local minimum

[0294] MIZ minimum

[0295] PST process control data

[0296] P1, P2, P3 positions

[0297] QD Quality Data

[0298] R Edge

[0299] RAh Axis of rotation of the hollow shaft

[0300] RAs Rotation axis of the reflector

[0301] RAv Virtual rotation axis

[0302] RS Relative motion control data

[0303] RZ Rotation Center

[0304] S Movement direction / scanning direction of the irradiated surface

[0305] SA Light path / beam axis of the combined energy beam

[0306] SB Grayscale image

[0307] SD Scan Control Data

[0308] SE Mirror Plane

[0309] SK Secant

[0310] SP1 First intensity distribution / top hat intensity distribution

[0311] SP2 Second intensity distribution / Gaussian intensity distribution

[0312] ST coating control data

[0313] S1 Beam path / beam axis of the first energy beam

[0314] S2 Beam path / beam axis of the second energy beam

[0315] TS Carrier Control Data

[0316] V vertical direction

[0317] VB reinforcement area

[0318] x, y plane

[0319] z direction

[0320] Ω Rotation speed

[0321] α angle

[0322] Polar angle.

Claims

1. A method for irradiating a material (13) with at least one energy beam (AL), wherein: The irradiation surface (AF) of the energy beam (AL) moves over the material (13), wherein: - generating at least a first energy beam (EL1) and a second energy beam (EL2), and - the first energy beam (EL1) and the second energy beam (EL2) are coupled into an energy beam movement unit (23) in a common beam path (SA) so that they move together as a combined energy beam (AL) over the material (13), and - wherein the second energy beam (EL2) is moved relative to the first energy beam (EL1) only before the coupling into the energy beam movement unit (23), wherein the relative movement of the second energy beam (EL2) relative to the first energy beam (EL1) is performed periodically, wherein the second energy beam (EL2) is repeatedly moved to the same position on a closed curve within the combined energy beam (AL).

2. The method according to claim 1, wherein: The method is used to locally melt the material (13).

3. The method according to claim 1, wherein: At least one first energy beam (EL1) and one second energy beam (EL2) are generated and at least partially superimposed as a combined energy beam (AL) and moved in a coordinated manner at a preset scanning speed over the material (13), wherein the second energy beam (EL2) moves at a preset relative speed relative to the first energy beam (EL1), the relative speed being greater than the scanning speed.

4. The method according to claim 3, wherein: The relative speed is at least 2 times greater than the scanning speed.

5. The method according to claim 3, wherein: The relative speed is at least 5 times greater than the scanning speed.

6. The method according to claim 3, wherein: The relative speed is at least 10 times greater than the scanning speed.

7. The method according to claim 3, wherein: The relative speed is at least 50 times greater than the scanning speed.

8. The method according to claim 3, wherein: The relative speed is at least 100 times greater than the scanning speed.

9. The method according to claim 1 or 2, wherein: The intensity of the second energy beam (EL2) is modulated according to its relative position to the first energy beam (EL1) and / or according to a current direction of movement (S) of an irradiation surface (AF) of the combined energy beam (AL).

10. The method according to claim 1 or 2, wherein: The first energy beam (EL1) and the second energy beam (EL2) have different intensity distributions (SP1, SP2), wherein the first energy beam (EL1) has an intensity distribution (SP1) which is rotationally symmetric about the beam axis (S1), and / or Therein, the second energy beam (EL2) has an intensity distribution (SP2) which is rotationally symmetric about the beam axis (S2).

11. The method according to claim 10, wherein: The first energy beam (EL1) has a top-hat intensity distribution.

12. The method according to claim 10, wherein: The second energy beam (EL2) has a Gaussian intensity distribution.

13. The method according to claim 1 or 2, wherein: The second energy beam (EL2) has a smaller maximum beam spread than the first energy beam (EL1) when coupled into the energy beam movement unit (23) in a common beam path (SA).

14. The method according to claim 1 or 2, wherein: The relative movement of the second energy beam (EL2) relative to the first energy beam (EL1) and / or the intensity modulation of the second energy beam (EL2) takes place periodically.

15. The method according to claim 14, wherein: The relative movement of the second energy beam (EL2) relative to the first energy beam (EL1) and / or the intensity modulation of the second energy beam (EL2) is carried out uniformly.

16. The method according to claim 1 or 2, wherein: The second energy beam (EL2) moves along a circular trajectory (K) along an edge (R) of the intensity distribution (SP1) of the first energy beam (EL1).

17. The method according to claim 1 or 2, wherein: The relative movement of the second energy beam (EL2) relative to the first energy beam (EL1) and / or the intensity modulation of the second energy beam (EL2) is carried out as follows: the combined energy beam (AL) moving on the material (13) has a total intensity distribution (GIV) at the irradiation surface (AF) of the material (13) in a section plane (x, y) extending perpendicularly to the beam axis of the combined energy beam (AL), the total intensity distribution being integrated over a time period - having at least one local minimum (MIZ) in a middle region along at least one secant (SK) in said section plane (x, y), and - having an intensity profile (IPK) which is surrounded along an edge (R) of the total intensity distribution (GIV), the intensity profile having a maximum value (MAX) at at least one location and having a local minimum value (MIN) in a region of the intensity profile (IPK) opposite the maximum value (MAX).

18. A method for additive manufacturing of a manufactured product (2), wherein: A building material (13) is selectively cured and for this purpose is irradiated with at least one combined energy beam (AL) at a building zone (8) using a method according to any one of claims 1 to 17.

19. An irradiation device (20) for irradiating a material (13) with at least one combined energy beam (AL), wherein: The irradiation surface (AF) of the energy beam (AL) moves on the material (13), and the irradiation device at least comprises: - an energy beam source system (21) for generating at least one first energy beam (EL1) and one second energy beam (EL2), - a first energy beam movement unit (30, 33, 33') for moving the second energy beam (EL2) relative to the first energy beam (EL1), - an energy beam combining device and a second energy beam movement unit, which are designed and arranged relative to one another so that the first energy beam (EL1) and the second energy beam (EL2) are coupled into the second energy beam movement unit in a common beam path (SA) so that they move together as a combined energy beam (AL) over the material (13), - wherein the second energy beam (EL2) is moved relative to the first energy beam (EL1) only before the coupling into the second energy beam movement unit, wherein the relative movement of the second energy beam (EL2) relative to the first energy beam (EL1) is performed periodically, wherein the second energy beam (EL2) is repeatedly moved to the same position on a closed curve within the combined energy beam (AL).

20. The irradiation device (20) according to claim 19, wherein: The energy beam combining device comprises a beam combiner (22), which is arranged upstream of the second energy beam motion unit and couples the first energy beam (EL1) and the second energy beam (EL2) into the energy beam motion unit (23) in parallel with each other, wherein the beam combiner (22) comprises a polarizer.

21. The irradiation device (20) according to claim 20, wherein: The beam combiner (22) comprises a thin-layer polarizer.

22. The irradiation device (20) according to claim 19, wherein: The first energy beam movement unit (30, 33, 33') comprises a rotation unit (31, 36, 36') having a rotatable optical element (32, 35, 35').

23. The irradiation device (20) according to claim 22, wherein The first energy beam movement unit (30, 33, 33') has a transmission beam displacement element (32) as a rotatable optical element, which is arranged in an inclined manner in the optical path of the second energy beam (EL2) so as to be rotatable about a rotation axis (RAh), wherein the rotation axis (RAh) extends coaxially with the optical path of the incoming second energy beam (EL2), and / or A reflector as a rotatable optical element (35, 35') is arranged obliquely in the light path of the second energy beam (EL2) and rotatably around a rotation axis (RAs), whereby the emitted light path during operation extends at an angle relative to the rotation axis (RAs), and wherein another optical element is arranged downstream of the reflector (35, 35') in another light path (S2) of the second energy beam (EL2), and the other optical element is reversed during operation of the light path output from the reflector (35, 35'), so that the light path rotates on a virtual cylindrical outer surface around a virtual rotation axis (RAv) as the reflector (35, 35') rotates, and at the same time always extends parallel to the virtual rotation axis (RAv).

24. The irradiation device (20) according to claim 23, wherein: The transmission beam displacement element (32) is a flat plate.

25. The irradiation device (20) according to claim 23, wherein The reflector is a mirror.

26. The irradiation device (20) according to claim 23, wherein The other optical element is a converging lens (37, 37').

27. The irradiation device (20) according to any one of claims 19 to 26, further comprising: - A control device (50) which controls the irradiation device (20) so that the first energy beam (EL1) and the second energy beam (EL2) are at least partially superimposed and move in a coordinated manner as a combined energy beam (AL) at a preset scanning speed over the material (13), wherein the second energy beam (EL2) moves at a preset relative speed relative to the first energy beam (EL1), the relative speed being greater than the scanning speed.

28. The irradiation device (20) according to claim 27, wherein The irradiation device (20) is used to locally melt the material (13).

29. The irradiation device (20) according to claim 27, wherein The relative speed is at least twice greater than the scanning speed.

30. The irradiation device (20) according to claim 27, wherein The relative speed is at least five times greater than the scanning speed.

31. The irradiation device (20) according to claim 27, wherein: The relative speed is at least ten times greater than the scanning speed.

32. The irradiation device (20) according to claim 27, wherein The relative speed is at least fifty times greater than the scanning speed.

33. The irradiation device (20) according to claim 27, wherein: The relative speed is at least one hundred times greater than the scanning speed.

34. An apparatus (1) for additive manufacturing of a manufactured product (2) in a manufacturing process, wherein: A building material (13) is constructed and selectively cured, wherein the material (13) is irradiated with at least one energy beam (AL) for curing in a building zone (8), wherein an irradiation surface (AF) of the energy beam (AL) moves over the building zone (8), wherein the device (1) has at least one irradiation device (20) according to any one of claims 19 to 33.

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