DE102017107362A1 - Method for the additive production of a three-dimensional component and method for calculating a scanning strategy for the purpose of corresponding activation of a system for the additive production of a three-dimensional component - Google Patents

Abstract

A process for the additive production of a three-dimensional component from a plurality of component layers by multiple incremental, in particular layered, adding powdered, wire or ribbon, in particular metallic, component starting material and, in particular incremental, shaping consolidation by each selective melting and / or sintering of the component starting material by means of a by at least one energy source, in particular local, introduced according to a scanning strategy amount of heat, characterized in that the interpretation of the trajectories of the heat input based on a, in particular simulation-based, determined local heat dissipation capability, a method for calculating a scanning strategy for the purpose of a corresponding view of a plant for additive manufacturing a three-dimensional component and a related facility.

Description

The present invention relates to a method for the additive production of a three-dimensional component from a plurality of component layers by multiple incremental, in particular layer by layer, adding powder, wire or tape, in particular metallic, component starting material and, in particular incremental, shaping solidification by each selective melting and / or Sintering of the component starting material by means of a heat quantity introduced by at least one energy source, in particular locally, in accordance with a scanning strategy, and a method for calculating a scanning strategy for the purpose of corresponding activation of a system for the additive production of a three-dimensional component.

In particular, it is about additive manufacturing processes in which the energy input, in particular heat input, takes place locally.

By "component" is meant a component including building board (base plate) and support structure (s). In addition, the term "component" is also a component set, such. B. a manufactured in a construction job in a space construct, the e.g. of several, e.g. identical, individual components may consist.

As the energy source (s), for example, an arc, a plasma jet, a laser beam, electron beam or the like may be used. The additive manufacturing process may in particular be a jet-based additive manufacturing process, such as e.g. selective laser melting or selective electron beam melting. The component starting material can be made of metal, plastic or ceramic. It may also be e.g. a powder, a powder cored wire or filler band.

The additive manufacturing process, which is also referred to as a generative manufacturing process, may be, for example, arc, plasma, laser and electron beam deposition welding and general build-up welding, in particular powder coating, laser and electron beam melting, laser sintering and all other processes in which material is selectively applied in the melt to generate a component.

As a material application method, e.g. Powder or wire coating welding with additive production of metallic materials or e.g. Fused deposition modeling technologies for the additive generation of plastic components conceivable.

In today's systems for the additive production of three-dimensional components, the trajectories of the energy input, in particular the heat input, designed mainly purely geometrically. Here, a subdivision of the layer geometry to be generated into individual, usually rectangular segments (often called "island" or "strip") takes place. Within a segment, equidistant rectilinear trajectories (called exposure vectors or scan vectors) are laid out parallel to the segment boundaries. The actual energy or heat input is e.g. by a laser along an exposure vector. With the aid of a scanning device, several exposure vectors within a segment are generated one after the other. In other words, the amount of energy or heat is introduced by means of a scanning strategy. The term "scanning strategy" is intended here primarily to describe the consolidation of a defined area in a layer of a component starting material with the already generiated (consolidated) part of the component by fusion , Welding, sintering or solidification by means of at least one moving (in particular punctiform) energy source, taking into account deflection paths or exposure paths (scan patterns) and beam parameters and the time dependence of the deflection paths and directional dependence of the deflection paths to produce desired component and Gefugeeigenschaften be meant. The scan strategy includes a scan pattern. This is the geometric description of the deflection paths or connecting lines of successive energy inputs, for example when pulsing, for solidifying the component contour and / or the component cross-section by means of at least one beam or another heat source.

According to the DE 100 42 134 C2 a better uniformity of the energy or heat input is achieved in that the position of the individual segments is selected at random when generating a component layer.

During an additive manufacturing process, thermal build-up and, in particular, local overheating ("hotspots") may result from layered buildup and local energy input, particularly near component edges. This can lead to an impairment of the component quality and in particular the surface of the component due to Ansinterungseffekten or undesirable local deformations (delay).

The present invention is therefore based on the object to provide a method for the additive production of a three-dimensional component with which components can be manufactured in a better quality.

According to the invention, this object is achieved in the generic method in that the design of the trajectories and / or the order and / or direction of the trajectories of heat input on the basis of, in particular simulation-based, local heat dissipation capability or based on a function thereof in a respective component layer The determination of the local heat dissipation capability is in the DE 102016120998.8 A1 , the disclosure of which is incorporated herein by reference in its entirety.

In particular, it is a computer-implemented method.

The local heat dissipation capability characterizes the ability of a device area to carry heat to the interior of the device.

Advantageously, at least a portion of the trajectories of heat input along isolines or quasi-isolines of the determined local Wärmeabitungsfäfihigkeit is designed. Quasi-isolines are intended to mean lines that are quite close to isolines. The resulting traces of consolidation will be cooled more evenly, which will lead to a reduction in local residual stress and local distortion. The expected same thermal conditions along the entire trajectory ensure better local process stability (e.g., maintenance of the constant melt pool in selective laser melting).

There will usually be curved and long trajectories of energy or heat input. This has other advantages. According to the current state of the art in selective laser melting, the laser is repeatedly turned on and off in the generation of an exposure vector (trajectory) within a rectangular segment at the boundaries of this segment. This leads to local instabilities in the temperature field and to the formation of microdefects just in the border region between adjacent segments. According to a particular embodiment of the present invention, trajectories become much longer and energy sources or heat sources do not need to be turned on and off as often. This simultaneously increases the overall build-up rate and enables higher material quality with fewer microdefects.

Physically, a trajectory provides a consolidation trace such as e.g. a melting trace / welding path in the selective laser melting of metallic materials or a solidified wire trace in the method of fused deposition modeling of thermoplastics. This track has a certain width, which depends on the process parameters (e.g., power of the beam and its speed). The individual traces of consolidation are advantageously designed so that they touch or overlap, so that the entire consolidated component layer is completely sealed. Therefore, advantageously, the trajectories representing a center line of these tracks should be designed with a distance such that the corresponding tracks intersect at a predetermined degree.

In particular, it may be provided that the trajectories are self-contained lines. The trajectories are advantageously designed along the isolines. The isolines, when they are completely inside the component, are always self-contained. The trajectories along these isolines can be self-contained, but they do not have to be The isolines that come to a component boundary are not self-contained. Accordingly, the trajectories along these isolines are not self-contained.

According to a particular embodiment, the trajectories are designed such that at least a portion of the heat input trajectory begins at one isoline having a particular value of local heat sink capability and ends at another isoline with a different local heat sink capability value.

In particular, it may be provided that the trajectories of the heat input are scanned from isolines having a low value of local heat dissipation capability to isolines having a higher value of local heat dissipation capability.

Advantageously, the time interval between successive trajectories is reduced.

According to a particular embodiment, the heat input is increased in the transition to the next consecutive trajectory by increasing the power of the power source and / or reducing the speed of the power source.

It may also be contemplated that the trajectories of heat input are scanned from isolines having a higher value of local heat dissipation capability to isolines having a lower value of local heat dissipation capability.

In particular, it can be provided that the time interval between successive trajectories is increased.

In addition, it can be provided that the heat input is reduced in the transition to the next successive trajectory by reducing the power of the power source and / or increasing the speed of the power source.

Advantageously, the direction of scanning individual trajectories of the heat input is determined based on the values of the local gradient of the heat dissipation capability.

In particular, it may be provided that the trajectories of the heat input are generated in the direction of a higher value of the gradient of the local heat dissipation capability.

According to a further particular embodiment of the invention, the component layer is produced by means of a plurality of energy sources acting simultaneously in different locations of the component layer, in particular with a plurality of lasers or with a locally split light source.

In particular, it may be provided that at least one pair of consecutively following trajectories is generated simultaneously from the sequence for generating the trajectories with the aid of two different energy sources.

The present invention also provides a method for the calculation of a scanning strategy for the corresponding activation of a system for the additive production of a three-dimensional component, wherein the design and / or order and / or direction of the trajectories (T _1; T ₂ ; T _c ) of the Heat input based on a, in particular simulation-based, determined local heat dissipation capability or based on a function of the same takes place in a respective component layer.

In particular, it may be provided that at least part of the trajectories of the heat input along isolines or quasi-isolines of the determined local heat dissipation capability is designed.

According to a particular embodiment, the trajectories are designed such that at least a portion of the heat input trajectory begins at one isoline having a particular value of local heat sink capability and ends at another isoline with a different local heat sink capability value.

It can also be provided that a component layer is segmented on the basis of a local heat dissipation capability and a trajectory is applied within the boundaries of one of the segments of this component layer.

Desirably, isolines or quasi-isolines or points are selected at an isoline of local heat dissipation capability to confine a segment.

In particular, however, it can be provided that at least part of the segment boundaries is aligned in the direction of the gradient of the heat dissipation capability or substantially perpendicular to the isolines or quasi isolines of the local heat dissipation capability.

According to another particular embodiment of the present invention, a trajectory of the heat input is assigned an area around this trajectory as a consolidation area.

According to another particular embodiment, the consolidation range is defined based on a calculation of the thermal field from a moving energy source along the trajectory of the heat input.

In particular, it may be provided that the consolidation range of a trajectory is defined as an area in which the temperatures have reached a certain predetermined value, in particular the value of the melting temperature of the consolidated material.

Advantageously, the consolidation areas of the adjacent trajectories overlap.

It can also be provided that the consolidation areas of all trajectories in the respective component layer cover the area of these component layers without gaps.

According to a particular embodiment it can be provided that the trajectories of the heat input are designed starting from isolines with a low value of the local heat dissipation ability to isolines with a higher value of the local heat dissipation capability.

Alternatively, it may be provided that the trajectories of heat input are laid out from isolines having a higher value of local heat dissipation capability to isolines having a lower value of local heat dissipation capability.

Advantageously, the direction of scanning of individual trajectories of the heat input is determined based on the values of the local gradient of the heat dissipation capability.

In particular, it may be provided that the trajectories of the heat input are designed in the direction of a higher value of the gradient of the local heat dissipation capability.

• - ein Bauraumgehäuse mit einer Bauplattform zur Abstützung eines oder mehrerer pulverbett-basiert additiv zu fertigenden Bauteils/Bauteile,
• - eine Schichtenpräparierungseinrichtung zur Präparierung jeweiliger Pulverschichten auf der Bauplattform,
• - eine Bestrahlungseinrichtung zur Bestrahlung der jeweils zuletzt präparierten Pulverschicht auf der Bauplattform und
• - eine Steuereinrichtung zur Steuerung der Bestrahlungseinrichtung gemäß einem Verfahren nach einem der Ansprüche 1 bis 28.

Furthermore, the present invention provides a system for additive production of a three-dimensional component of several component layers by multiple incremental, especially layer by layer, adding powdered, wire or strip, in particular metallic, component starting material and, in particular incremental, shaping consolidating the component starting material by each selective melting and / or sintering by means of an amount of heat introduced by at least one energy source, in particular locally, in accordance with a scanning strategy

• a construction space housing with a construction platform for supporting one or more powder-bed-based additive components / components to be manufactured,
• a layer preparation device for preparing respective powder layers on the building platform,
• - An irradiation device for irradiating the last prepared powder layer on the building platform and
• - A control device for controlling the irradiation device according to a method according to one of claims 1 to 28.

Finally, the present invention also provides one or more computer-readable media that includes computer-executable instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 28 to perform.

The present invention is based on the surprising finding that, by designing the trajectories and / or the chronological sequence of the heat input of the scanning strategy on the basis of a local, in particular simulation-based, localized heat dissipation capability in a respective component layer, the component quality is better compensated by the temperature field within the component can be improved, overheated areas and / or component distortion can be avoided and the total time can be reduced for the construction process and the productivity of additive plants can be increased.

• - besserer Temperaturausgleich innerhalb des generierten Bauteils,
• - verringerte Gefahr lokaler Überhitzungen,
• - Verringerung der Eigenspannungen und Verzugs,
• - Erhöhung des gesamten Prozessstabilität,
• - gleichmäßigere Verteilung von Bauteileigenschaften.

The invention focuses on a rapid dissipation of the introduced energy within the component, which at the same time can lead to at least one of the following advantages:

• better temperature compensation within the generated component,
• - reduced risk of local overheating,
• - reduction of residual stresses and distortion,
• - increasing the overall process stability,
• - more even distribution of component properties.

• 1 eine schematische Darstellung zur Erläuterung der Definition der lokalen Wärmeableitungsfähigkeit;
• 2 eine schematische Darstellung zur Erläuterung des Begriffes „Trajektorie“;
• 3 eine schematische Darstellung zur Erläuterung eines Verfahrens zur additiven Fertigung eines dreidimensionalen Bauteils aus mehreren Bauteilschichten unter Verwendung von mehreren Energiequellen gemäß einer besonderen Ausführungsform der vorliegenden Erfindung;
• 4 eine Seitenansicht eines achsensymmetrischen Bauteils;
• 5 eine Draufsicht auf das Bauteil von 4;
• 6 eine beispielhafte lokale Verteilung D_i der Wärmeableitungsfähigkeit D^loc in einer Bauteilschicht L_i des Bauteils von 4;
• 7 Isolinien I₁, I₂ und I₃ der lokalen Verteilung D_i der Wärmeableitungsfahigkeit in einer Bauteilschicht L_i aus der 6;
• 8 eine Auslegung von Trajektorien gemäß einer besonderen Ausführungsform der vorliegenden Erfindung;
• 9 eine Auslegung von Trajektorien gemäß einer weiteren besonderen Ausführungsform der vorliegenden Erfindung;
• 10 eine Trajektorie gemäß einer besonderen Ausführungsform der vorliegenden Erfindung;
• 11 ein Beispiel eines Segments S einer Bauteilschicht;
• 12 ein Segment S_q, das sich durch Modifikation des Segments S der 11 ergibt;
• 13 eine Auslegung von Trajektorien gemäß einer weiteren besonderen Ausführungsform der vorliegenden Erfindung;
• 14 ein Beispiel einer Trajektorie mit einem Konsolidierungsbereich B₁ mit einer Breite b₁;
• 15 ein Beispiel zweier Trajektorien mit einem jeweiligen Konsolidierungsbereich B₁ bzw. B₂;
• 16 ein Beispiel zweier Trajektorien mit einem jeweiligen Konsolidierungsbereich B₁ bzw. B₂;
• 17 eine Draufsicht auf eine Bauteilschicht L_i;
• 18 eine beispielhafte Verteilung eines Temperaturgradienten in einer Bauteilschicht; und
• 19 eine Auslegung bzw. Ausrichtung von Trajektorien gemäß einer besonderen Ausführungsform der vorliegenden Erfindung.

Further features and advantages of the invention will become apparent from the appended claims and the following description in which several embodiments are explained in detail with reference to the schematic drawings. Showing:

• 1 a schematic representation for explaining the definition of the local heat dissipation ability;
• 2 a schematic representation for explaining the term "trajectory";
• 3 a schematic illustration for explaining a method for additive manufacturing of a three-dimensional component of a plurality of component layers using a plurality of energy sources according to a particular embodiment of the present invention;
• 4 a side view of an axisymmetric component;
• 5 a plan view of the component of 4 ;
• 6 an exemplary local distribution D _{i of} the heat dissipation capability D ^loc in a component layer L _{i of} the component of 4 ;
• 7 Isolines I ₁ , I ₂ and I _{3 of} the local distribution D _{i of} the heat dissipation ability in a device layer L _i from the 6 ;
• 8th an interpretation of trajectories according to a particular embodiment of the present invention;
• 9 an interpretation of trajectories according to another particular embodiment of the present invention;
• 10 a trajectory according to a particular embodiment of the present invention;
• 11 an example of a segment S of a device layer;
• 12 a segment S _q resulting from modification of the segment S of the 11 results;
• 13 an interpretation of trajectories according to another particular embodiment of the present invention;
• 14 an example of a trajectory with a consolidation range B ₁ with a width b ₁ ;
• 15 an example of two trajectories with a respective consolidation range B ₁ and B ₂ ;
• 16 an example of two trajectories with a respective consolidation range B ₁ and B ₂ ;
• 17 a plan view of a device layer L _i ;
• 18 an exemplary distribution of a temperature gradient in a component layer; and
• 19 a design of trajectories according to a particular embodiment of the present invention.

In general, the heat dissipation capability D ("dissipation") of the component layer is defined as the integral of the heat flow q [W / m ² ] over the surface s [m ² ] (see FIG. 1 ): $$D={\displaystyle {\oint }_{S}qnds}={\displaystyle {\int }_{V}div\left(q\right)dV={\displaystyle {\int }_{V}div}}\left(-\lambda Grad\left(T\right)\right)dV$$

n is the normal vector to the surface s; V is the considered volume, m ³ ; T is the temperature, K; λ is the thermal conductivity, W / (mK).

The local heat dissipation capability can be calculated from the heat equation: $$D={\displaystyle {\int }_{V}div}\left(q\right)={\displaystyle {\int }_V\left(Q-c\rho \frac{\partial T}{\partial t}\right)dV}$$

Q is the power of the heat source in volume V, [W / m ³ ]; c is the specific heat capacity, [J / (kgK)]; ρ is the density, [kg / m ³ ]; t is the time, [s].

At a certain point P of the component (V → o), the local heat dissipation capability D ^loc is then defined as follows $$D^{lOc}=div\left(q\right)=Q-c\rho \frac{\partial T}{\partial t}$$

The local heat dissipation capability depends not only on the material properties (heat conduction, heat capacity, density) and heat input. It is also affected by the boundary conditions, such. As the local component geometry, strongly influenced.

oder $$D^{loc}=Q-c\rho \frac{\partial T}{\partial t}$$

zur Ermittlung der lokalen Wärmeableitungsfähigkeit zu verwenden, wobei in beiden Füllen auch noch die lokale Bauteilgeometrie zu berücksichtigen ist.As the above statements show, there are thus at least two possible independent ways of determining the local heat dissipation capability of a point of a device layer, $$D^{lOc}=div\left(q\right)=div\left(-\lambda Grad\left(T\right)\right)$$

or $$D^{lOc}=Q-c\rho \frac{\partial T}{\partial t}$$

to use for determining the local heat dissipation ability, in which case the local component geometry must also be taken into account in both fillings.

For the times of a pure cooling of a point of the component layer, ie for the times in which the heat source in the considered point no longer works (power of the heat source Q = o) gives the second from the above-mentioned calculation paths an even simpler form of representation: $$D^{lOc}=-c\rho \frac{\partial T}{\partial t}$$

This representation of local heat dissipation capability allows for easy determination of the ability of a particular point to dissipate the heat at a particular time. The higher the cooling rate at the point under consideration at a certain time, the higher the local heat dissipation capability.

In general, the temperature distribution and the cooling or heating rate in the component and, accordingly, the local heat dissipation capability changes with time. Therefore, it makes sense to integrate the local heat dissipation capability over a certain time and to use the resulting value for the characterization of the heat dissipation at a certain point. For the times of a pure cooling of a point of a component layer, ie heat input = zero, the following value results: $$D_{int}^{lOc}=-{\displaystyle {\int }_{t_1}^{t_2}c\rho \frac{\partial T}{\partial t}dt=-{\displaystyle {\int }_{t_1}^{{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="DE102017107362A1\_0018.png,DE102017107362A1\_0020.png"\; state="\{\{state\}\}">t</figure-callout>}}_2}\frac{\partial H}{\partial t}dt}}=-\Delta H$$

ΔH is the change in enthalpy, J, in the time interval from t ₁ to t ₂ .

Assuming the temperature-independent material properties, the local heat dissipation capability can be characterized by the change in temperature: $$D_{int}^{lOc}=-\Delta H=-c\rho \Delta T$$

zum anfänglichen Temperaturgradienten darstellt: $$D_{rel}^{loc}=\frac{D_{int}^{loc}}{\frac{\partial T\left(x,y,z\mathrm{,0}\right)}{\partial z}}$$

As a useful value for characterizing the local heat dissipation capability, a relative local heat dissipation capability has been shown, which is a relation between $D_{int}^{lOc}$

represents the initial temperature gradient: $$D_{rel}^{lOc}=\frac{D_{int}^{lOc}}{\frac{\partial T\left(x.y.z\mathrm{,\; 0}\right)}{\partial z}}$$

All depictions of local heat dissipation capability (as enthalpy or temperature change) described above can be easily determined by calculating the temperature field (thermal calculation).

Indirect Physical Interpretation of Value of Local Heat Dissipation Capability: The heat in an additive manufacturing process is normally transported primarily downwardly from a generated device layer to the interior of the device. In this case, the value of a local heat dissipation capability indirectly indicates the amount of the mass of the "cold" consolidated material below the specific point of the component layer. The more "cold" material mass is below a certain point of a device layer, the higher the value of local heat dissipation capability.

For a direct thermal calculation of the build process, a sequential thermal activation of all component layers / segments would be necessary. Such a procedure would require correspondingly numerous time steps and would be associated with a high calculation effort.

According to a particular embodiment of the present invention, by a simplified execution of the numerical simulation, the determination of the local heat dissipation capabilities can be made much faster. The entire component is calculated without thermal activation of individual component lights / segments. Such a simplified simulation will lead to a drastic reduction in the required computation times (the larger the component, the greater the savings in computation time).

As an initial condition, in this or another embodiment, an "artificial" temperature distribution with in the direction of construction ( z Direction) of increasing temperature. The initial temperature gradients T in the x and y directions are used as zero: $$\{\begin{array}{c}\frac{\partial T\left(x.y.z\mathrm{,\; 0}\right)}{\partial z}>0\\ \frac{\partial T\left(x.y.z+\Delta z\mathrm{,\; 0}\right)}{\partial z}\ge \frac{\partial T\left(x.y.z\mathrm{,\; 0}\right)}{\partial z}\\ \frac{\partial T\left(x.y.z\mathrm{,\; 0}\right)}{\partial x}=\frac{\partial T\left(x.y.z\mathrm{,\; 0}\right)}{\partial y}=0\end{array}$$

Such a temperature distribution as an initial condition mimics the temperature distribution in the real building process. For each component layer, this distribution ensures that the heat flow at the beginning of the calculation takes place exclusively downwards.

A particularly effective variant of the abovementioned initial condition represents a constant temperature gradient in the direction of construction: $$\{\begin{array}{c}\frac{\partial T\left(x.y.z\mathrm{,\; 0}\right)}{\partial z}=cOnst>0\\ \frac{\partial T\left(x.y.z\mathrm{,\; 0}\right)}{\partial x}=\frac{\partial T\left(x.y.z\mathrm{,\; 0}\right)}{\partial y}=0\end{array}$$

The constant initial temperature gradient in the assembly direction, predefined for each point of the component and thus also for each component layer, has the same zero value of the local heat dissipation capability: $$\begin{array}{c}{D}^{lOc}\left(x.y.z\mathrm{,\; 0}\right)=div\left(q\left(x.y.z\mathrm{,\; 0}\right)\right)=div\left(-\lambda Grad\left(T(x.y.z\mathrm{,\; 0}\right)\right)=\\ =div\left(-\lambda \left(\frac{\partial T\left(x.y.z\mathrm{,\; 0}\right)}{\partial x}+\frac{\partial T\left(x.y.z\mathrm{,\; 0}\right)}{\partial y}+\frac{\partial T\left(x.y.z\mathrm{,\; 0}\right)}{\partial z}\right)\right)=\\ =div\left(-\lambda \left(cOnst+0+0\right)\right)=O\end{array}$$

The zero value of the local heat dissipation capability for each point of the device provides a convenient starting point to represent subsequent changes in local heat dissipation capability at each component point.

In general, as described above with reference to an embodiment, the initial temperature distribution is simply assumed. For a more accurate determination of the initial temperature distribution, both simplified solutions, such as a fast one- or two-dimensional calculation of the temperature field in the build process, as well as experimental measurements can be used.

In addition to the initial conditions, boundary conditions can also be defined. Some particularly advantageous boundary conditions should be mentioned separately:

Constant heat flow over the entire calculation area

In this variant, the boundary conditions of the heat flow at the top of q _{(top; English: top)} and at the bottom q _{(below; English: bottom) is} constant and corresponds to the predetermined initial constant temperature gradient grad (T (x, y, z, o )) in the component: $$q_{tOp}=q_{bOttOm}=-\lambda Grad\left(T\left(x.y.z\mathrm{,\; 0}\right)\right)=cOnst$$

The other edges of the component are thermally insulated, which means that the temporal heat flow always has a zero value.

At a constant temperature gradient, the initial local heat dissipation capability has a zero value at each point in the calculation area (justification given above).

For the same upper and lower surface of the calculation area, this constraint ensures a flow of the same amount of energy through the entire computation area. After a certain time for these boundary conditions to reach a stationary state of the temperature field, that is, after a redistribution of the temperature, the "new" temperature remains stable at each point. This also stabilizes the values of local heat dissipation capability. It generally makes sense to expect this to be stationary or near-steady state.

This variant of the boundary conditions is particularly suitable for determining the local heat dissipation capability in local areas of the component. Such local calculations, for example, examine the heat build-up in the vicinity of a channel or defect, such as a pore or other undesirable void. The local calculations of this kind can find an application in the context of a monitoring system (see below).

Full thermal isolation of the entire calculation area

A full thermal isolation of the entire calculation area represents a variant of the boundary conditions, which is very well suited for the determination of the local heat dissipation capability in the components (in the context of the so-called global calculations (thermal calculation of the whole component)). It may then be sufficient to calculate up to a first maximum of the temperature change (and not up to a stationary or almost stationary state).

The field of local heat dissipation capability can be determined numerically by a thermal computation for a given component (in advance).

In a method for additive manufacturing of a three-dimensional component 1 the component is built up in layers by means of one or more energy sources (as part of an irradiation device), in the present example by means of a laser (not shown) (s. 2 ). The laser delivers a laser beam 50 that in this example from a scanner 60 is steered. The consolidation of a component layer L ₁ takes place with the aid of the laser beam 50 by generating multiple trajectories, only one of which is shown and with the reference number 30 The point on the trajectory should indicate the starting point, while the arrowhead indicates the end point.

In the 3 is a system with two energy sources, in this example each a laser (not shown) shown. Each of the two lasers delivers a respective laser beam 51 respectively. 52 , In this example, there are two different trajectories 31 and 32 with the laser beams 51 respectively. 52 generated at the same time.

The 4 shows a side view of an axisymmetric component 1 with an outer surface 2 , It is in this example a frusto-conical component. The component 1 has an upper diameter d ₁ and a lower diameter d ₂ on. The construction direction is marked by z.

The 5 shows a plan view of the component 1 from 4 ,

In the 6 is a local distribution D _{1 of} the heat dissipation capability D ^loc in a device layer L _i of the component 1 of the 4 shown. The component layer L _i is at a height H _i , Because the component 1 is symmetrical, the field of wall conduction is also symmetric. With the reference number 3 is the outer edge of the component layer L _i that on the outside surface 2 is located marked. The surface 2 forms a barrier to the free flow of heat downwards (against the construction direction z ). The closer to the edge 3 in the component layer L _i The more the heat accumulates and the lower the heat dissipation capacity. In the middle area (within the diameter d ₂ ) the heat flow down is not prevented. Therefore, the values of the local wall dissipation capability remain unchanged equal to zero (all initial values of the local wall dissipation capability in the device have a zero value due to the above-described initial condition with the constant temperature gradient in the structure direction).

7 shows associated isolines I ₁ . I ₂ and I ₃ the local heat dissipation ability D _i in the component layer L _i from 6 with the edge 3 , The values C ₁ . C ₂ and C ₃ are constants. Due to the symmetry of the component 1 the isolines are also symmetrical. The isolines I ₃ and the outer edge 3 the component layer L _i are identical due to symmetry.

8th concerns an example, the two trajectories T ₁ and T ₂ shows that along the isolines I ₁ and I ₂ be generated.

9 shows an example in which the trajectories T ₁ and T ₂ along quasi-isolines, that is, based on the isolines I ₁ and I ₂ , be generated.

10 shows an example of a trajectory T ₁ with a starting point on an isoline I ₁ and one endpoint on a different isoline I ₂ the heat dissipation ability.

11 shows an example of a design of the boundaries of a segment S after the isolines. I _a and I _b are the isolines of local heat dissipation ability, P ₁ and P ₂ are two points on the isoline I _a , G ₁ and G ₂ are gradients of heat dissipation capability at these points. The points P ₃ and P ₄ arise by crossing the isoline I _e with the directions of the gradients G ₁ and G ₂ , The resulting segment S is in the 11 also shown.

In the 12 is the segment S has been modified to a segment S _q . The boundaries of the segment S _q are based on the points on the isolines I _a and I _b educated.

In the 13 There is an isoline I _c in a segment S (please refer 13 (a) ). Based on this isoline I _c will be within the segment S a trajectory T _c designed (see 13 (b) ). In the general case, the trajectory does not necessarily have to run along an isoline. For example, it could be a straight line between the start and end points of the isoline, or another line that is substantially parallel to segment boundaries.

In the 14 is now a trajectory T ₁ with a consolidation area B ₁ with a width b ₁ shown.

The 15 shows two trajectories T ₁ and T ₂ with a respective consolidation area B ₁ respectively. B ₂ that touch, but do not overlap.

In the 16 Now a case is shown in which the trajectories T ₁ and T ₂ consolidation areas B ₁ respectively. B ₂ that overlap.

In the 17 are the trajectories T ₁ and T ₂ arranged so that by their respective consolidation areas B ₁ respectively. B ₂ the component layer L _i with a surface 3 is completely covered.

From the 18 gives an example of a distribution of a temperature gradient: the denser the isolines I ₁ . I ₂ and I ₃ are, the larger the temperature gradients. Therefore, the temperature gradient increases at the transition from P ₂ over P ₃ (or P ₄ ) too P ₁ , B _HG is an area with the highest temperature gradients (HG - high gradient) and B _LG is an area with the lowest temperature gradients (LG - low gradient).

Finally, the shows 19 an example of the design or alignment of trajectories according to the height or the size of the temperature gradient. All trajectories T ₁ . T ₂ . .. , T ₁₂ begin in the region of the lowest temperature gradients and run in the direction of increasing the temperature gradient. The order of the individual trajectories may be, for example, as follows: first, the trajectories are generated in areas of lowest values of heat dissipation capability (between the isolines I ₃ and I ₂ ).

For the possible use of multiple energy sources: Suppose that the trajectories are generated with the help of, for example, two lasers. Then, for example, the trajectories T ₁ and T ₂ generated at the same time. This allows a more uniform and particularly symmetrical distribution of the temperature field.

Of course, the sequence described above may be altered, reduced or supplemented.

The features of the invention disclosed in the foregoing description, in the drawings and in the claims may be essential both individually and in any desired combinations for the realization of the invention in its various embodiments.

LIST OF REFERENCE NUMBERS

1

component

2

surface

3

outer edge

30, 31, 32

trajectories

50, 51, 52

laser beams

60

scanner

b ₁ , b ₂

spread

B ₁ , B ₂

consolidation areas

B _HG , B _LG

consolidation areas

C ₁ , C ₂ , C ₃

constants

D _i

local distribution of heat dissipation ability

d ₁

upper diameter

d ₂

lower diameter

G ₁ , G ₂

gradient

H _i

height

I ₁ , I ₂ , I ₃

Isolines of heat dissipation ability

I _a , I _b , I _c

contours

L _i ,

device layer

P _1, P _2, ... P ₄

Points

S

segment

T ₁ , T ₂ ,

trajectories

T _c

trajectories

z

build direction

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10042134 C2 [0008]
• DE 102016120998 A1 [0011]

Claims (30)

Method for the additive production of a three-dimensional component (1) from several component layers by multiple incremental, in particular layered, adding powder, wire or belt, in particular metallic, component starting material and, in particular incremental, shaping consolidation by respectively selective melting and / or sintering Component output material by means of a by at least one energy source, in particular locally, introduced according to a scanning strategy amount of heat, characterized in that the design and / or the order and / or direction of the trajectories (T ₁ , T ₂ , T _C ) of the heat input based on a , in particular simulation-based, determined local heat dissipation capability or based on a function of the same takes place in a respective component layer. Method according to Claim 1 , wherein at least a part of the trajectories (T ₁ , T ₂ , T _C ) of the heat input along isolines (I _a , I _b , I _c ) or quasi-isolines of the determined local heat dissipation ability is designed. Method according to Claim 1 wherein the trajectories (T _1, T ₂ , T _C ) are designed such that at least a portion of the heat input trajectory begins at an isoline having a particular value of local heat dissipation capability and ends at another isoline having a different local thermal dissipation capability value , The method of any one of the preceding claims, wherein trajectories of heat input are scanned from isolines having a low value of local heat dissipation capability to isolines having a higher value of local heat dissipation capability. Method according to Claim 4 , wherein the time interval between successive trajectories is reduced. Method according to Claim 4 or 5 wherein the heat input is increased in the transition to the next consecutive trajectory by increasing the power of the power source and / or reducing the speed of the power source. Method according to one of Claims 1 to 3 wherein the trajectories of heat input are scanned from isolines having a higher value of local heat dissipation capability to isolines having a lower value of local heat dissipation capability. Method according to Claim 7 in which the time interval between successive trajectories is increased. Method according to Claim 7 or 8th wherein the heat input is reduced in the transition to the next consecutive trajectory by reducing the power of the power source and / or increasing the speed of the power source. The method of any one of the preceding claims, wherein the direction of scanning individual trajectories of heat input is determined based on the values of the local gradient of heat dissipation capability. Method according to Claim 10 wherein the trajectories of heat input are generated toward a higher value of the gradient of local heat dissipation capability. Method according to one of the preceding claims, wherein the component layer by means of several, simultaneously acting in different locations of the component layer energy sources, in particular with a plurality of lasers or with a spatially split light source is generated. Method according to Claim 12 in which at least one pair of consecutively following trajectories is generated at the same time from the sequence for generating the trajectories with the aid of two different energy sources. Method for calculating a scanning strategy for the purpose of corresponding activation of a plant for the additive production of a three-dimensional component, wherein the design and / or the order and / or the direction of the trajectories (T _1, T ₂ , T _C ) of the heat input based on a, in particular simulation-based , determined local heat dissipation ability or by a function of the same takes place in a respective component layer Method according to Claim 14 wherein at least a part of the trajectories (T _1, T ₂ , T _C ) of the heat input along isolines (I _a , I _b , I _c ) or quasi-isolines of the determined local heat dissipation capability is designed. Method according to Claim 14 wherein the trajectories (T _1, T ₂ , T _C ) are designed such that at least a portion of the heat input trajectory begins at one isoline with a particular local heat value and ends at another isoline with a different local heat sink capability value , Method according to Claim 14 wherein a device layer is segmented based on a local heat dissipation capability and a trajectory is applied within the boundaries of one of the segments of that device layer. Method according to Claim 17 where isolines or quasi-isolines or points on an isoline of local heat dissipation ability are selected to confine a segment. Method according to Claim 18 wherein at least a portion of the segment boundaries are aligned in the direction of the gradient of the heat dissipation capability or substantially perpendicular to the isolines of the local heat dissipation capability. Method according to one of Claims 14 to 19 wherein a trajectory of the heat input is assigned an area around this trajectory as a consolidation area. Method according to Claim 20 wherein the consolidation range is defined by calculating a thermal field from a moving energy source along the trajectory of the heat input. Method according to Claim 21 in which the capitalization range of a trajectory is defined as an area in which the temperatures have reached a certain predetermined value, in particular the value of the melting temperature of the consolidated material. Method according to one of Claims 20 to 22 , where the consolidation areas of the adjacent trajectories overlap. Method according to one of Claims 20 to 23 , Wherein the consolidation regions of all trajectories in the respective component layer completely cover the surface of this component layer. Method according to Claim 14 , where the trajectories of heat input are designed from isolines having a low value of local heat dissipation capability to isolines having a higher value of local heat dissipation capability. Method according to Claim 14 wherein the trajectories of heat input are designed from isolines having a higher value of local heat dissipation capability to isolines having a lower value of local heat dissipation capability. Method according to one of Claims 14 to 26 wherein the direction of scanning individual trajectories of the heat input is determined based on the values of the local gradient of the heat dissipation capability. Method according to Claim 27 wherein the trajectories of the heat input are designed towards a higher value of the gradient of local heat dissipation capability. Plant for the additive production of a three-dimensional component from several component layers by multiple incremental, in particular layered, adding powder, wire or ribbon, in particular metallic, component starting material and, in particular incremental, shaping consolidating the component starting material by each selective melting and / or sintering by means of a by at least one energy source, in particular locally, amount of heat introduced according to a scanning strategy, comprising - a package housing with a building platform for supporting one or more powder-based additive component / components, - a layer preparation device for preparing respective powder layers on the construction platform, - an irradiation device for irradiating the respectively last-prepared powder layer on the construction platform and - a control device for controlling the irradiation device according to a method na one of the Claims 1 to 28 , One or more computer-readable media / media comprising computer-executable instructions that, when executed by a computer, cause the computer to perform the method of any one of Claims 1 to 13 and / or the method according to one of Claims 14 to 28 perform.

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