WO2018233867A1

WO2018233867A1 - Method for the simulation-based optimisation of the form of a three-dimensional component to be developed and subsequently produced, more particularly additively produced

Info

Publication number: WO2018233867A1
Application number: PCT/EP2018/000306
Authority: WO
Inventors: Vasily POLSHIKHIN
Original assignee: Amsis Gmbh
Priority date: 2017-06-20
Filing date: 2018-06-12
Publication date: 2018-12-27
Also published as: DE102017113483A1; WO2018233867A8

Abstract

The present invention relates to a method for the simulation-based optimisation of the form of a three-dimensional component to be developed and subsequently produced, more particularly additively produced. More particularly, the present invention relates to a method for the automated optimization of the component topology with the aim of improved heat dissipation. According to the invention, the form of the component to be developed is iteratively optimized proceeding from an initial form by adding and/or subtracting component volume at local sites on the component using values of local heat dissipation capacity, said values being determined by means of simulation, or using a function of heat dissipation capacity during the production and/or the application of the developed component.

Description

"Method for simulation-based optimization of the shape of a three-dimensional component to be developed and later, in particular additive, to be produced"

The present invention relates to a method for simulation-based optimization of the shape of a three-dimensional component to be developed and later, in particular additive, to be produced. In particular, the present invention relates to a method for the automated optimization of the component topology for the purpose of better heat dissipation. The term "component" is intended to cover both the actual component alone and the actual component including support structure.

According to the current state of the art, an optimization of the topology (shape) of a three-dimensional component to be developed and later, in particular additive, to be produced takes place structurally. The focus of the known optimization is the goal to reduce the mass of the component with a constant strength. The adaptation of the component geometry is based on mechanical calculations.

Thermal calculations or simulations are used in the design of such components, such as cooled tools or heat exchangers. Due to the calculations of the temperature distribution, manual adjustments are made according to the method of trial-and-error of the component geometry. The thermal calculations are repeated for the adjusted geometries until the developer releases the final component geometry.

In the additive manufacturing of components, the thermal process plays an important role. Stowage areas of the heat can adversely affect the final properties of the component as well as the quality of the surface. From practice it is already known that certain geometries for the process from a thermal point of view are very unfavorable.

CONFIRMATION COPY A well-known example of such an unfavorable geometry are channels which are oriented transversely to the construction direction and have a round cross-section. In the upper part of the channel, the process heat accumulates, which leads to increased sintering effects in this area. These areas must be supported to better transport the heat down, which reduces the permeability of the channels. Therefore, it is recommended to design a cross section in the form of a "falling droplet" with the orientation of the tip of the droplet in the direction of construction already in the design of such channels.This geometry dissipates the heat better and also makes it possible to dispense with the support points. The task of manual design with the tip always in the direction of construction, however, is not trivial when a channel along a very complex direction-changing three-dimensional line runs, which is very often the case in the contour near cooling of the tool surfaces.

The present invention is therefore based on the object to provide a method for simulation-based automated thermal optimization of the component geometry to improve the heat dissipation. This process optimizes thermally stressed components for their use (for example, tools with near net cooling). A particularly important field of application is the optimization of the topology of additively manufactured components for better heat dissipation during the build-up process. Due to the process-oriented optimization of the component topology, it will be possible to avoid heat build-up in the component and also to reduce the number of necessary support points or support structures. In addition, the support structures around the generated component are also thermally optimized to perform the same function with less mass.

According to the invention, this object is achieved by a method for simulation-based optimization of the shape of a three-dimensional component to be developed and later, in particular additively produced, wherein, starting from an initial shape of the component to be developed, the shape iteratively by addition or / and subtraction of component volume of local Component location is optimized based on simulation-based local heat dissipation capability values or a function thereof during manufacture and / or application of the developed device. According to a particular embodiment, it can be provided that the local heat dissipation capability is calculated as a divergence of a heat flow or as a function thereof, in particular as a time integral of the divergence of the heat flow over a specific time interval.

It is also conceivable that the local heat dissipation capability is calculated as the divergence of the negative product of a thermal conductivity of the component starting material and a local temperature gradient, in particular as a time integral of the divergence of said product in a specific time interval.

Again, it can be provided that the local heat dissipation capability is calculated on the basis of a temporal derivative of the local temperature or a function thereof, in particular as a time integral of the negative product of the temporal derivative of the local temperature, the heat capacity of the component starting material and the density of the component starting material in a specific time interval becomes.

Advantageously, the local heat dissipation capability is calculated as the difference between a heat input and the product of the temporal derivative of the local temperature, the heat capacity of the component starting material and the density of the component starting material or as a function of said difference, in particular as a time integral of that difference over a given time interval.

In particular, it can be provided that the heat input is set equal to zero. With this assumption, the phases of a "pure cooling" of a component layer are simulated, ie the times of cooling immediately after heating with the heat source Since the heat source (eg laser) acts only locally in a component layer, the times of "pure cooling" in each point of a device layer normally much larger than the times of heating with the heat source. As an "energetic replacement" or "energetic equivalent" of a heat source, such calculations will have an artificial initial condition in which the initial temperature of the next layer is higher than the initial temperature of the preliminary layer. Such an initial condition provides a slope of the initial temperature in the direction of construction (see below). Advantageously, the heat capacity and the density of the component starting material are assumed to be constant.

According to a further particular embodiment of the present invention, a numerical simulation of the temperature distribution in the whole component is carried out starting from an initial temperature distribution in order to determine the local heat dissipation capability.

In particular, it can be provided that it is assumed for components to be produced additively that the initial temperature increases in the direction of construction. Such an artificial initial condition mimics a temperature distribution in the component during its generation. It enables a very fast calculation of the temperature distribution during the "pure cooling" of the layers.An important physically justified simplification is that the heating effect of the heat source is represented by the artificial increase of the temperature of the layers in the direction of construction Simplified thermal equivalent of a heat source Simplified calculations are much faster than computations that need to consider heating with a heat source, and the "pure cool down phase" is mapped identically in both simplified and complex calculations. As a result, the simplified calculations provide comparable information on the expected areas of heat build-up as well as on the parts areas with good heat dissipation.

In addition, it can be provided that an initial temperature gradient in the direction of construction is assumed to be constant.

Conveniently, initial temperatures are assumed to be constant across the mounting direction.

According to another particular embodiment of the present invention, a boundary condition for the numerical simulation of the temperature distribution is defined such that there is complete thermal isolation of the entire calculation area. Advantageously, the calculation of the temperature distribution is carried out by a numerical method, such as the method of finite differences or finite elements, for the solution of the partial heat dissipation equation.

According to another particular embodiment of the present invention, changing the initial shape of the component by adding and / or subtracting a component volume at local locations of the component includes comparing the simulation-based local thermal dissipation capability values with a local thermal dissipation capability limit.

In a particular embodiment of the present invention, the method comprises a) dividing the component volume into individual volume elements, b) determining the component region to be optimized, c) determining the limit of the heat dissipation capability and the target value of the heat dissipation capability and a maximum number of calculation cycles d) a first calculation e) Comparison of the values of the calculated local heat dissipation capability in individual volume elements of the component region to be optimized with the limit value of the heat dissipation capability. f) Change of the component volume in the component region to be optimized by addition of new volume elements and / or subtraction of existing volume elements the comparison of the values in step (e), g) recalculation of the heat dissipation capability in the whole component taking into account the added and / or subtracted volume elements, and h) repeating steps (e) through (g) until a predefined number of repetition steps are reached or until the target local heat dissipation capability is reached in each volume element of the device.

In particular, it may be provided that a change in the component volume is carried out by subtraction of volume elements at the local locations at which the value of the heat dissipation capability is lower than the limit value of the heat dissipation capability.

Conveniently, a process is performed wherein a change in component volume is made by subtracting volume elements at the local locations where the value of local heat dissipation capability is higher than the local heat dissipation capability limit.

Alternatively it can be provided that a change of the component volume takes place by addition of new volume elements at the local locations of the component surface at which the value of the local heat dissipation capability is lower than the limit value of the local heat dissipation capability.

Alternatively, it may be provided that a change in the component volume takes place by addition of new volume elements at the local locations of the component surface at which the value of the local heat dissipation capability is higher than the limit value of the local heat dissipation capability.

In another alternative, a change in component volume may be made by adding new volume elements at the local locations of the device surface where the value of local heat dissipation capability is greater than the local heat dissipation capability limit.

Conveniently, at least two non-adjacent localities on a surface of a component having dissimilar values of local heat dissipation capability are interconnected by the addition of the new volume elements.

In addition, it can be provided that for at least one cross section of a component or a part of this cross section, the addition and / or subtraction of Volume elements is performed so that the average local heat dissipation capability in this cross section or part of this cross section is in an interval between predefinable minimum and maximum local thermal dissipation target values.

Furthermore, it can be provided that for additively manufactured components, the addition and / or subtraction of volume elements for at least two different component sections with orientation transverse to the mounting direction is performed so that the mean value of the local heat dissipation capability in both component sections in an interval between predefinable minimum and maximum target values the local heat dissipation ability is.

Finally, the present invention provides one or more computer-readable media / 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 22 perform.

The present invention is based on the surprising finding that thermal dissipation during production of the component can be improved by "thermal" topology optimization.Of course, after the "thermal" topology optimization has been performed, it must be checked whether the proposed modified component is mechanically optimized.

Further features and advantages of the invention will become apparent from the appended claims and from the following description, in which an embodiment will be explained with reference to the schematic drawings. Showing:

Figure 1 is a schematic representation for explaining the definition of the local

Heat dissipation capability;

FIG. 2 initial conditions for a component;

FIG. 3 shows an initial distribution of isotherms in a component, a change in the temperature distribution in a component, a calculated temperature distribution and a calculated distribution of the local heat dissipation capability in a component at a time T;

Phases of a method for simulation-based optimization of the shape of a to be developed and later, in particular additive, to produce three-dimensional component according to a particular embodiment of the present invention; a schematic representation of the topology optimization of a channel in a component; for example, an initial constant temperature gradient in the direction of construction (z-axis) of a rod-shaped component; for example, a rod-shaped component with orientation exactly in the direction of construction (z-axis); the rod-shaped component of Figure 8b at an angle cd to the horizontal; the rod-shaped component of Figure 8b at an angle a ₂ to the horizontal, with c> a ₂ ; a schematic representation of the topology optimization of the component of Figure 8c; schematic representations (top) and examples (bottom) for a topology optimization of the components according to the components in Figures 8b - 8d; Figure Ii is a schematic representation of the topology optimization of a component in order to reduce a support structure;

FIG. 12 shows the component of FIG. 1 with, by way of example, a reduced support structure;

FIG. 13 shows, by way of example, a schematic representation of topology optimization for the purpose of designing and optimizing a support structure;

Figure 14 shows two examples of topology optimization for design and

Optimization of a support structure for the component of Figure 13, and

FIG. 15 shows, by way of example, a schematic representation of topology optimization for

Design a near-contour cooling in a tool to improve heat dissipation.

For a better understanding, the term local heat dissipation capability is first discussed here. The local heat dissipation capability characterizes the ability of a particular device area to remove the heat. In general, the heat dissipation capability D ("dissipation") of the component layer is defined as the integral of the heat flow q over the surface s (FIG. 1):

The local heat dissipation capability can be calculated from the heat equation:

Q is the power of the heat source in volume V, c is the heat capacity, p is the density, ί is the time.

At a certain point P of the component (V ^ o), the local heat dissipation capability D ^loc is then defined as follows: dT

div {q) = Q - cp-

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.

As the above statements show, there are at least two possible

independent ways to determine the local heat dissipation capability of a point of a device layer therein,

div (q) = div (-grad (T)) or

(2) D ^t0C = <2 - cp ^

to use for determining the local heat dissipation ability, in both cases, the local component geometry is also taken into account.

For the periods of pure cooling of a point of the device layer, i. for the times in which the heat source in the point under consideration no longer works (heat source Q = o), the second one of the above-mentioned calculation paths gives an even simpler form of representation:

dT

This representation of the local heat dissipation capability allows a simple determination of the ability of a particular point to dissipate the heat at a given 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 rate in the component and, accordingly, the local heat dissipation capability change 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:

ΔΗ is the change of the enthalpy in the time interval from o to τ.

Assuming the temperature-independent material properties, the local thermal conductivity can be characterized by the change in temperature:

The two representations of the local heat dissipation capability can be easily determined by calculating the temperature field (thermal calculation).

Indirect physical interpretation of the value of local heat dissipation capability

The heat in an additive process is normally removed mainly downwards, from a generated component layer into the interior of the component. Here, the value of local heat dissipation capability indirectly indicates the amount of "cold" consolidated material below the particular point of the device layer, the more "cold" material mass is below a particular point of a device layer, the higher the value of local heat dissipation capability , Calculation method for determining local heat dissipation capability

The thermal simulations for determining the local heat dissipation capability can be performed with all numerical methods for the solution of the partial heat equation, such. For example, the finite element method or the finite difference method.

In a simplified implementation of the numerical simulation, the determination of the local heat dissipation capability can be faster. For this purpose, an artificial temperature distribution, with the temperature rising in the direction of construction and a constant temperature gradient, is used as the initial condition. Such an initial condition mimics the temperature distribution in the real building process. The heat flow at the beginning of the calculation takes place exclusively downwards (in the Z direction).

Such a simplified simulation will drastically reduce the required computation times. For the determination of o. G. Temperature distribution can u.a. simplified solutions (such as 1 or 2-dimensional calculations of the building process) can be used.

This will be explained with reference to Figures 2 to 5.

As an initial condition, in this or another embodiment, an "artificial" temperature distribution with increasing temperature in the direction of construction (z-direction) is used The initial temperature gradients T in the x and y directions are used as zero (see Figure 2a; with a channel 12):

Such a temperature distribution as an initial condition mimics the temperature distribution in the real building process. Ensured for each component layer this distribution that the heat flow at the beginning of the calculation is only downwards.

A particularly effective variant of the abovementioned initial condition represents a constant temperature gradient in the direction of construction (see FIG. 3b):

The constant initial temperature gradient in the assembly direction, predefined for each point of the component and therefore also for each component layer, has the same zero value of the local heat dissipation capability:

D ^loc (x, y, z, 0) = div (q (x, y, z, 0)) = div (-Xgrad (T x, y, z, Q)) =

= div (-X (const + 0 + 0)) = o

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.

The initial conditions described above lead to a flat shape of the isolines of the temperature field (see Figure 3, left). FIG. 3 shows the initial distribution of the isotherms in a component 10 with a channel 12. A zero value of the temperature gradient transversely to the mounting direction leads to the formation of flat isolines (Ti Tj. Ti...) Of the temperature field.

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 1- or 2-dimensional calculation of the Temperature field used in the construction process as well as experimental measurements.

During the calculation, the regions of heat build-up "reveal" themselves by a redistribution of the temperature throughout the component The heat-build areas, ie all critical component areas, can then be identified, for example, by the slope of the value Di _n t ^loc (see FIG 4 shows the temperature distribution at or after a time τ (FIGURE 4b) and the initial temperature distribution (FIGURE 4a) A new distribution of isotherms results In the upper portion of the component 10, a build-up of heat (Di _n t Fig. 5 shows once again the temperature distribution of Fig. 4b) and the associated distribution of the temporally integral local heat dissipation capability at the time τ., Τ can be, for example, the time from which nothing ^ceases as a result of the calculation or not much changes, that is, a stationary or near-steady state is reached.

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

1) Constant heat flow over the entire calculation area

In this variant of the boundary conditions, the heat flow at the top C [(top) and at the bottom Q (bottom) is constant and corresponds to the given initial constant temperature gradient grad (T (x, y, z, o)) in the component:

Qtop = bottom = grad (T {x, y, z, 0)) = 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, thus stabilizing also the values of local heat dissipation capability In general, it makes sense to count up to this stationary or almost stationary 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).

2) 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).

In general, the new method provides for a targeted local material adaptation (subtraction or addition) depending on the value of local heat dissipation capability (Figure 6).

The subtractive method variant may comprise the following steps: a first thermal calculation of the distribution of the local heat dissipation capability in the entire component 10,

Definition of the device area to be optimized (e.g., areas having a negative local heat sink capability) based on a threshold of a desired local heat dissipation capability,

Subtraction of the material from the component areas to be optimized, a new thermal calculation of the distribution of the local heat dissipation capability for the new component geometry, l6

this process (material subtraction and thermal conductivity determination) repeats as soon as at any point (or point) of the optimized surface or in any point of the component (or in a particular point of the component) the value of local heat dissipation capability exceeds a predefined local threshold Heat dissipation capability exceeds.

A particularly effective method is the subtraction of a material region bounded by an isoline of local heat dissipation capability

(Figure 6, upper portion of the optimized cooling channel 12). The "cutting" of the

Material takes place along this isoline.

The additive method may comprise the following steps: a first thermal calculation of the local heat dissipation capability distribution in the entire component 10,

Definition of the device area to be optimized (e.g., regions having a positive local heat dissipation capability) based on a threshold of a desired local heat dissipation capability,

Addition of the material to the component areas to be optimized, a re-thermal calculation of the distribution of heat dissipation capability for the new component geometry, this process (material addition and determination of heat dissipation ability) repeats itself as soon as at each point (or point) of the optimized surface or in At any point of the device (or at a particular point of the device), the value of local heat dissipation capability exceeds a predefined threshold of local heat dissipation capability. A particularly effective method of addition is to add the material to a surface which has been bounded by an isoline of local heat dissipation capability (Figure 6, lower portion of the optimized cooling channel 12). The locally added amount of material can be calculated as a function of the value of local heat dissipation capability on that surface.

A combination of the two methods described above can be used very effectively at the same time, as has been illustrated in FIG. 6 using the example of optimizing a cooling channel 12. This results in a drop-shaped geometry of an originally round geometry of the cooling channel 12. The limits of the new channel geometry have a total of a higher heat dissipation capability in comparison with the limits of the old geometry. The entire cross section has hardly changed due to the subtraction in the upper and addition in the lower range (if necessary, a condition for the constant cross section in such calculations can also be taken into account).

The new drop-shaped geometry also has great advantages in terms of production by means of additive manufacturing. It is expected that less powder will be sintered in the upper part of the cooling channel. This avoids the danger that the cooling channels will be clogged completely or partially by the sintered powder. In addition, the new teardrop-shaped geometry need not be provided with support structures or support structures, since almost all areas of the surface are oriented in the overhang at an angle of more than 45 ^° to a building panel (not shown). In contrast, the original circular geometry would have to be supported, which would have a negative effect on the permeability of the cooling channel.

Optimization of the topology based on the condition of equal integral heat dissipation capability

A further advantageous variant of the method is based on the optimization of the topology on the basis of the condition of the same integral heat dissipation capability. Normally, different heat flows through the different cross-sections of the components. A significant reduction in the mass of the components can be achieved by optimizing the components topologically so that over any cross-section always the same (or comparable) amount of heat is transported away. The cross-sectional area is designed so that a following condition is met:

Dloc ^int is the local heat dissipation capability, A is the area of a cross section; DA is a limit and ADA is the tolerance range of the desired integral heat dissipation capability.

FIG. 7 shows a further particular embodiment of a method for simulation-based optimization of the shape of a three-dimensional component to be developed and later, in particular additive, to be produced. A component 10 should have a channel 12. In the present example, the channel 12 has a circular cross-section. The surface of the channel is identified by the reference numeral 13. Simulation-based calculations have revealed that the device will have a base surface 17 with a high local heat dissipation capability and a surface 16 to support with a low local heat dissipation capability. By adding a new volume element 11, a connection or bridging from the surface 16 to the base surface 17 and thus better heat dissipation from the surface 16 is achieved.

FIGS. 8 to 10 serve to illustrate a method for simulation-based optimization of the shape of a three-dimensional component to be developed and later, in particular additive, according to a particular embodiment of the present invention, the component being geometrically identical but differently oriented in the construction space.

FIG. 8 a shows an initial, constant temperature gradient in the direction of construction (z-axis). This mimics the temperature gradient in the buildup process. It is the same for all three rod-shaped components shown in FIGS. 8b to 8d which are geometrically identical but differently oriented in the construction space. In FIG. 8b, the rod-shaped component 20 is oriented exactly in the direction of construction (z-axis). In contrast, in FIGS. 8c and 8d, the same component 20 is arranged with different orientations with regard to the construction direction or horizontal (angle cti and a ₂ ). The component 20 is an axisymmetric cylindrical rod.

By still following thermal topology optimization (see below), the cross section of the rod-shaped member 20 will change depending on the orientation to the mounting direction or to the horizontal.

In FIG. 9, for the component 20 oriented at an angle c to the horizontal in FIG. 8c, the surface 23 of the component is a region 26 with a low heat dissipation capability, a region 27 with a high heat dissipation capability, an axis of symmetry Xi or the orientation of the element Component 20, a projection xy a plane with orientation parallel to a build platform (not shown) or transverse to the mounting direction (z-axis) and a viewing plane Xi yi (see also Figure 10).

FIG. 10 shows a cross-sectional view (viewing plane) for the component 20 according to FIGS. 8b-8d above

in FIG. 9) and the original round surface of the component 20 and, if present, a region 26 with a low heat dissipation capability and a region 27 with a high heat dissipation capability.

A change in the cross section of the rod-shaped component 20 with the different orientation to the mounting direction 8 (z-axis) or to the horizontal due to the thermal topology optimization according to a particular embodiment is shown in FIG. Reference numeral 24 denotes the new surface of the component 20 after topology optimization. In FIG. 10a (relating to the component according to FIG. 8b), the topology does not change since the heat dissipation capability in cross section is the same everywhere. In this example, a change in the topology in the cases shown in FIGS. 10b and 10c and relating to the component 20 according to FIGS. 8c and 8d is made by: an increase in volume in the region 27 of higher heat dissipation capability and a subtraction of the volume in the region 26 of low heat dissipation capability.

Figures 11 and 12 are illustrative of an example of thermal topology optimization for an additive build process to reduce the necessary support structure (s). FIG. 11 a shows a rod-shaped, axisymmetric component 30 with a rod diameter d _a and a conical surface 33 at the lower end of the component 30, the tip of the cone being oriented counter to the construction direction (z-axis). Since the surface 33 extends to the tip at an angle ct ₃ to the z-axis (see Figure 11a) and the angle a _{3 is} greater than 45 degrees, the surface 33 must be supported (see also supporting elements 35 in Figure 12a).

Figure 11a additionally shows a region 36 with a low heat dissipation capability. In this region 36, a heat accumulation with the lowest heat dissipation capability forms just at the tip of the cone.

FIG. 11b shows a new surface 34 of the component 30 after a topology optimization according to a particular embodiment of the present invention. In this example, the topology is changed by addition of volume in the low heat dissipation capability region 36. In this case, more volumes are added at local points where the heat dissipation capability is lower. This results in the new surface 34. This surface 34 must be less supported compared to the initial surface 33, since in a large part of the new surface 34, the angle α between a tangent to the new surface 34 and the mounting direction (z-axis) is more than 45 degrees.

FIG. 12 shows a non-optimized (see FIG. 12a) and an optimized (see FIG. 12b) component 30 from FIG. 11 with corresponding support elements 35. In the case shown in FIG. 12b, fewer support elements are required than in the case shown in FIG. 12a. FIGS. 13 and 14 serve to illustrate examples of a thermal topology optimization for an additive buildup process for the purpose of designing and optimizing a support structure.

FIG. 13 shows a side view (FIG. 13a) and a front view (FIG. 13b) of a component 40 and isolines 48 of the local heat dissipation capability Di _n t ^loc . In addition, a low heat dissipation capability region 46 and a high heat dissipation capability region 47, and a build platform 41 are also shown.

For FIGS. 14a-d, the following is to be stated:

In FIGS. 14a-b, support elements 45 are designed by connecting the region 46 with a low heat dissipation capability (see FIG. 13) and a region 47 with a high heat dissipation capability (see FIG. 13) by means of plate-shaped support elements 45.

In FIGS. 14c-d, the support elements 45 are optimized by subtracting a volume from the region 47 having a higher heat dissipation capability. In this case, the volume of the support elements 45 is reduced from bottom to top. The final geometry results from a condition that the heat dissipation capability on the supported surface 42 is greater than a critical threshold Cthr (threshold). The isoline 48 shown in FIG. 14 c represents the course of this boundary in the support element 45.

It is important to mention that the same result can also be achieved by a different approach, for example by adding volume to the regions 46 with a low heat dissipation capability. In this case, for example, without the intermediate steps shown in FIGS. 14a-b, volumes at local points of the surface 42, ie on a surface with a low heat dissipation capability, are added. The process repeats until the above condition (heat dissipation capability at the supported surface 42 is to be higher than a certain limit) is satisfied. Finally, FIG. 15 shows an example of a thermal topology optimization for the design of conformal cooling in a tool for better dissipation of the heat. A component 50, which is for example a lower part of a tool, is formed radially symmetrically with an inner diameter d, _n and an outer diameter ct. The component 50 has a surface 52 which is to be cooled. Reference numeral 53 denotes the initial geometry of the conformal cooling channels 53. The cooling channels extend radially symmetrically about an axis m and thus form rings close to the surface 52.

Reference numeral 54 in FIG. 15b denotes a new, optimized geometry of the cooling channels. Both in the figure 15a and in the figure 15b, the thermal load (heat flows) q _ra d, qaxiai are shown on the surface 52. These, on the surface of the tool during its use resulting heat flows are to be removed via the cooling channels.

The new cooling channels have been obtained by means of thermal topology optimization. The method can be analogous to the method according to FIG. In this case, the initially round cross-sectional geometry of the cooling channels will be transformed into the geometry of a "falling droplet." In contrast to FIG. 6, where the heat came exclusively from above and had to be conducted further down, in this case it comes from different directions from the surface 52. Accordingly, the orientation of the "falling droplets" changes. The tips rotate in the direction of the heat source, that is, the surface 52 to be cooled.

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 combinations for the realization of the invention in its various embodiments. LIST OF REFERENCE NUMBERS

10 component

11 volume element

12 channel

13 surface

16 surface

17 basic surface

20 component

23 surface

23 original surface

24 new surface

26 area with low heat dissipation capability

27 area with high heat dissipation capability

30 component

31 construction platform

33 conical surface

34 new surface

35 support elements

36 area with low heat dissipation capability

40 component

41 construction platform

42 supported surface

45 support elements

46 area with low heat dissipation capability

47 area with high heat dissipation capability

48 Limit line / isoline of heat dissipation capability 50 Component

52 surface

53 initial geometry

54 new geometry

q _ra d, qaxiai thermal stress

xy projection

xiyi viewing plane

xo, xi, x2 symmetry axes

Claims

claims

Method for simulation-based optimization of the shape of a three-dimensional component (10, 20, 30, 40, 50) to be developed and later, in particular additive, wherein, starting from an initial shape of the component to be developed, the shape is iteratively by addition or / and Subtraction of device volumes at local locations of the device is optimized based on simulation-based local heat dissipation capability values or a function thereof during manufacture and / or application of the developed device.

The method of claim 1, wherein the local heat dissipation capability is calculated as a divergence of a heat flux or as a function thereof, in particular as a time integral of the divergence of the heat flow in a certain time interval.

The method of claim 1, wherein the local heat dissipation capability is calculated as a divergence of the negative product of a thermal conductivity of the component starting material and a local temperature gradient, in particular as a time integral of the divergence of said product in a certain time interval.

The method of claim 1, wherein the local heat dissipation capability is calculated based on a temporal derivative of the local temperature or a function thereof, in particular as a time integral of the negative product of the temporal derivative of the local temperature, the heat capacity of the component starting material and the density of the component starting material in a certain time interval becomes.

The method of claim 1 or 4, wherein the local heat dissipation capability is a difference between a heat input and the product of the time derivative of the local temperature, the heat capacity of the constituent source material and the density of the constituent source material, or as a function of said difference. in particular as a time integral of this difference in a given time interval is calculated.

6. The method of claim 5, wherein the heat input is set equal to zero.

7. The method according to any one of claims 4 to 6, wherein the heat capacity and the density of the component starting material are assumed to be constant.

8. The method according to any one of the preceding claims, wherein for determining the local heat dissipation ability, a numerical simulation of the temperature distribution in the whole component (10, 20, 30, 40, 50) is carried out starting from an initial temperature distribution.

9. The method of claim 8, wherein for components to be produced by additive (10, 20, 30, 40, 50) it is assumed that the initial temperature increases in the direction of construction.

10. The method of claim 9, wherein an initial temperature gradient is assumed to be constant in the construction direction.

11. The method according to claim 9 or 10, wherein initial temperatures are assumed to be constant across the construction direction.

12. The method according to any one of claims 8 to 11, wherein a boundary condition for the numerical simulation of the temperature distribution is defined so that there is a complete thermal isolation of the entire computation area.

13. The method according to any one of claims 8 to 12, wherein the calculation of the temperature distribution with a numerical method, such. As the method of finite differences or finite elements, is performed for the solution of the partial heat dissipation equation.

14. A method according to any one of the preceding claims wherein changing the initial shape of the component (10, 20, 30, 40, 50) by adding or subtracting a volume of component at local locations of the component compares the simulation-based local heat removal capability values with a presettable local heat dissipation limit.

15. Method according to one of the preceding claims, comprising a) dividing the component volume into individual volume elements, b) determining the component region to be optimized, c) determining the limit of the heat dissipation capability and the target value of the heat dissipation capability and a maximum number of calculation cycles, d) a first Calculation of the heat dissipation capability in the entire component (10, 20, 30, 40, 50), e) comparison of the values of the calculated local heat dissipation capability in individual volume elements of the component region to be optimized with the limit value of the heat dissipation capability, f) change of the component volume in the component region to be optimized Addition of new volume elements (11) and / or subtraction of existing volume elements based on the comparison of the values in step (e), g) recalculation of the heat dissipation capability in the whole component (10, 20, 30, 40, 50) taking into account the added and / or subtracts h Volume elements (11), h) repetition of steps (e) to (g) until a predefined number of repetition steps is reached or until in each volume element of the Component (10, 20, 30, 40, 50) of the target value of the local heat dissipation ability is achieved.

16. A method according to claim 14 or 15, wherein a change of the component volume takes place by subtracting volume elements at the local places where the value of the local heat dissipation capability is lower than the limit of the local heat dissipation capability.

17. The method of claim 14, wherein a change in the volume of the component is made by subtracting volume elements at the local locations where the value of the local heat dissipation capability is higher than the local heat dissipation capability limit.

18. The method according to claim 14, wherein a change in the component volume takes place by addition of new volume elements (11) at the local locations of the component surface at which the value of the local heat dissipation capability is lower than the limit value of the local heat dissipation capability.

19. A method according to claim 14 or 15, wherein a change of the component volume takes place by addition of new volume elements (11) at the local locations of the component surface at which the value of the local heat dissipation capability is higher than the limit value of the local heat dissipation capability.

A method according to any one of the preceding claims, wherein at least two non-adjacent localities on a surface of a component (10, 20, 30, 40, 50) having dissimilar values of local heat dissipation capability are added by the addition of the new volume elements (11). be connected to each other.

21. The method according to any one of the preceding claims, wherein for at least one cross section of a component (10, 20, 30, 40, 50) or a part of this cross section, the addition and / or subtraction of volume elements so it is performed that the average local heat dissipation capability in this cross-section or part of that cross-section is in an interval between predefinable minimum and maximum local thermal dissipation target values.

Method according to one of the preceding claims, wherein for additively produced components (10, 20, 30, 40, 50), the addition and / or subtraction of volume elements for at least two different component cuts with orientation transverse to the mounting direction is performed so that the mean value of the local Heat dissipation capability in both component slices is in an interval between predefinable minimum and maximum local thermal dissipation target values.

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 the preceding claims.