DE102016200303A1 - Method for modeling a contact structure and computer-readable medium - Google Patents

Abstract

The invention relates to a method for modeling a contact structure (6) in the computer-aided design of an additively produced workpiece (100), the method comprising detecting a construction area (4) for the workpiece (100) to be produced additively on a model substrate (1 ') and acquiring design parameters for the additive-to-be-fabricated workpiece (100 ') and creating at least one geometry for the contact structure (6) in the design region (4) and depending on the design parameters, wherein the at least one geometry is calculated such that one a workpiece (100) produced additively by the substrate (1 ') of the model substrate (1) can be separated by dividing it from the substrate (1). A computer-readable medium is also specified, comprising executable program instructions which are suitable for having a data processing device carry out the described steps.

Description

The present invention relates to a method for modeling a contact structure in the computer-aided design of an additively manufactured workpiece and a corresponding computer-readable medium, for example a storage medium.

A computer-readable medium and a corresponding method are known, for example WO 2015/106020 A1 ,

The additive or generative production of workpieces or components usually takes place directly on the basis of computer-internal data models. In this case, the workpiece is preferably produced and / or constructed by a primary molding process, for example by means of powder bed-based processes, it being possible to dispense essentially essentially with machining operations. Known methods are in particular the selective laser melting (SLM: English for "Selective Laser Melting"), the selective laser sintering (SLS: English for "Selective Laser Sintering") and the electron beam melting (EBM: English for "Electron Beam Melting").

To display a component, for example by means of SLM, a powder bed is exposed by means of a laser beam in accordance with a predetermined exposure geometry, wherein the data can be generated from a 3D file. In a first step, the workpiece or component is divided into individual layers. In a second step, the tracks or vectors are generated for each layer, which moves off the laser beam. If a powder layer is exposed, the component platform is lowered and a new layer of powder is applied by means of a slider, for example a rake, and then exposed again with the laser, which melts and solidifies the powder. Often, in additive manufacturing, the workpiece is designed using common computer-aided designs or CAD (English for "Computer Aided Design"), and in particular in 3D constructions relevant material parameters are often simulated by means of finite element analysis (FEA).

Furthermore, through CAM technology (English for "Computer Aided Manufacturing") completely dispensed with the use of technical drawings.

Furthermore, support structures often have to be used in the SLM process in order, for example, to support overhangs in the workpiece relative to a production substrate or to a component platform during production and / or to dissipate the heat of the laser beam used to melt the powder. On the other hand, it is possible to dispense with support structures for particularly small parts to be manufactured in an additive manner, since heat removal is not such a big problem.

Since the workpieces are connected by the melting process (compare SLM and EBM process) preferably cohesively with a component substrate, the workpieces must be separated by the additive structure by complex mechanical or machining operations again from the substrate. As an alternative to this, it is also possible to resort to fracture structures ("easy-to-break" structures), in which case the workpiece can be separated from the substrate again by breaking or applying force after assembly.

The additive production of workpieces, such as plastics, ceramic workpieces or metallic workpieces such as turbine components, in particular parts in the hot gas path of gas turbines, offers a variety of advantages in terms of manufacturing and repair of these workpieces. Of particular importance in connection with the actual additive structure is also the processing or the handling of the design data, the simulation and the modeling of the corresponding component geometry. For example, the modeling of the above-mentioned complicated fracture structures proves to be particularly complicated in CAD design.

It is therefore an object of the present invention to provide means by which the stated problems can be solved and a corresponding construction and / or additive production of the workpieces can be improved.

This object is solved by the subject matter of the independent claims. Advantageous embodiments are the subject of the dependent claims.

One aspect of the present invention relates to a method for modeling a contact structure or a modeling method in the computer-aided design.

The computer-aided design can be referred to herein as a CAD and / or CAM method. The construction referred to in the present case relates to an additively produced workpiece. The contact structure is or is preferably formed so that it acts as a strong connection between the substrate and the workpiece to be produced during manufacture.

In one embodiment, the method is preferably feasible with a data processing device.

The method includes detecting a design area for the workpiece to be manufactured additively or its construction on a substrate or model substrate.

The model substrate is preferably a computer-aided constructed and / or modeled substrate which is intended to simulate a real substrate or its properties as accurately as possible, for example by means of FEA.

The construction area preferably describes a region of a base area of the workpiece to be produced and / or a corresponding model. Preferably, the construction area refers to the area of the workpiece to be manufactured additively, which is directly connected or connected to the substrate for the additive construction.

The method further includes detecting design parameters for the workpiece to be additively manufactured.

In one embodiment, the design parameters comprise material information about the materials as well as the material properties of the workpiece to be produced additively and / or of the substrate.

The method further includes creating and / or computing at least one geometry for the contact structure in the design area and depending on the design parameters. In this case, the virtual geometry may include a 3D model and / or another display, which may be displayed, for example, to a user or a person performing the described method.

The said at least one geometry is calculated in such a way that a workpiece produced additively on a real substrate corresponding to the model substrate can be separated from the substrate by cutting, for example mechanical and / or manual cutting. For this purpose, the contact structure may include, for example, one or more predetermined breaking points.

The workpiece is preferably constructed on the model substrate, and especially directly on the contact structure.

Said dicing preferably designates manual breaking or otherwise dicing without machining or machining.

By means of the described method, it is advantageously achieved to specify a contact structure which has been modeled automatically, without requiring "manual" modeling, for example individual contact structure elements. Conveniently, the described contact structure enables in a simple manner the release or separation of the workpiece from the substrate.

• – Erfassen eines Konstruktionsbereichs für das additiv herzustellende Werkstück auf dem Substrat bzw. Modellsubstrat,
• – Erfassen von Konstruktionsparametern für das additiv herzustellende Werkstück und
• – Erstellen mindestens einer Geometrie für die Kontaktstruktur in dem Konstruktionsbereich und in Abhängigkeit der Konstruktionsparameter, wobei die mindestens eine Geometrie derart berechnet wird, dass ein auf einem dem Modellsubstrat entsprechenden Substrat additiv hergestelltes Werkstück durch Zerteilen von dem Substrat getrennt werden kann.

A further aspect of the present invention relates to a computer-readable, preferably non-volatile medium or storage medium comprising executable program instructions which are suitable for having a data processing device carry out the following steps:

• Detecting a construction area for the workpiece to be produced additively on the substrate or model substrate,
• - Recording design parameters for the additive to be produced workpiece and
• Creating at least one geometry for the contact structure in the construction area and depending on the design parameters, wherein the at least one geometry is calculated such that a workpiece produced additively on a substrate corresponding to the model substrate can be separated from the substrate by dicing.

In one embodiment, the at least one geometry for the contact structure is calculated such that the geometry has a multiplicity of geometric elements for a plurality of contact structure elements of the contact structure. By means of this embodiment, a suitable contact structure can be formed particularly advantageously.

In one embodiment, each contact structure element is connected to the substrate and / or the model substrate via a contact surface.

According to the selected nomenclature, the geometry in the model thus corresponds to the contact structure in the real or physical world and the geometry elements corresponding to the contact structure elements.

In one embodiment, the contact surfaces are rectangular square, polygonal, circular and / or oval shaped.

In one embodiment, the sum of the surface areas of the contact surfaces by a multiple, for example, five times, ten times or twenty times smaller than an area of the construction area. With this configuration, the contact structure allows particularly useful the subsequent detachment or separation of the workpiece from the substrate.

In one embodiment, the geometry for the contact structure is calculated in such a way that the contact structure elements or their side surfaces each enclose an angle of greater than or equal to 45 ° with a surface of the substrate and / or the model substrate. Preferably, all of the said side surfaces of the contact structure elements form said angle with the substrate surface.

In one embodiment, a multiplicity of different geometries are calculated for different contact structures. This embodiment, for example, allows a user to make a choice about the modeled geometries.

In one embodiment, the various geometries are subsequently output to a user and / or displayed, that is, after the calculation, whereby the user can choose between the different geometries, for example, depending on the requirement of the workpiece or component.

In one embodiment, the at least one geometry of the contact structure is output and / or displayed to a user after computation, wherein geometry parameters, such as dimensions of the features and / or the contact features, subsequently applied by the user, i. after the calculation, can be edited and / or changed.

In one embodiment, the at least one geometry of the contact structure is calculated in such a way that a connection between the substrate and the workpiece to be produced thereon can withstand stresses between the workpiece and the substrate which arise during the additive production.

In one embodiment, the user is warned of a signal due to the calculation of the at least one geometry if the connection between the substrate and the workpiece to be produced thereon is additive to the stresses created during additive manufacturing due to the design region selection, design parameters, and / or design considerations possibly edited or changed by the user geometry parameter, not withstand.

Accordingly, after a change or input of the user with regard to the geometry parameters, a renewed modeling of the contact structure may be expediently necessary and carried out by the described method.

In one embodiment, in the calculation of the at least one geometry, stresses between the workpiece and the substrate, which arise during production of the workpiece to be produced additively, are calculated by means of a finite element analysis (FEA). In particular, residual stresses can be calculated by means of said FEA and / or limit values can be calculated for the surface area of the contact surfaces described above.

Another aspect of the present invention relates to an additive manufacturing method of a workpiece comprising the method described for modeling the contact structure. The additive manufacturing method further includes computer assisted designing of the additively manufactured workpiece and additive fabrication of the workpiece on the substrate from the modeled contact structure.

Furthermore, the additive manufacturing method may include compiling a numerical control program (CAM) after the computer aided design. The additive production of the workpiece can furthermore be carried out with the additive manufacturing method, for example by means of SLM, on the basis of the CAM data.

In one embodiment, after the additive fabrication, the workpiece is separated from the substrate by dicing, or the additive fabrication is separated from the substrate.

In one embodiment, the contact structure is initially, i. before the actual production or the additive construction of the workpiece or after constructing the workpiece to be produced, made additive.

In one embodiment, the production of the workpiece preferably takes place directly on the contact structure.

In one embodiment, the method described is a software module for a construction method for the additive production of a workpiece or component.

Another aspect of the present invention relates to a workpiece or component which is manufactured or producible with the described additive manufacturing method.

Embodiments and / or advantages which in the present case relate to the method for modeling and / or the additive manufacturing method can likewise relate to the computer-readable medium and vice versa.

In the exemplary embodiments and figures, identical or identically acting components may each be provided with the same reference numerals. The illustrated elements and their proportions with each other are basically not to be considered as true to scale, but individual elements, such as layers, components and areas for better representability and / or for better understanding can be shown exaggerated thick or large.

1 schematically indicates at least parts of a method for modeling a contact structure in the computer-aided design of a component.

2 shows a schematic sectional view of a geometry for an additive to be machined workpiece.

3 shows a schematic sectional view of a contact structure for an additive to be machined workpiece.

4 shows in a flowchart process steps of the method according to 1 ,

1 indicates in a plan a geometry for a contact structure (see reference numerals 6 in 2 or 3 ). The geometry includes a variety of geometric features 2 preferably for the modeling of a plurality of contact structure elements (see reference numerals 7 in 3 ) of the contact structure. The square geometry elements 2 have a dimension a. Alternatively, the geometry elements 2 have a rectangular shape (see dashed lines) also with dimensions a and b. Without this being explicitly indicated in the drawings, the geometry and / or the contact structure may have additional shapes, for example circular, oval or polygonal shapes.

Said contact structure is used to illustrate a method for modeling the contact structure in the computer-aided design of a workpiece to be produced additively 100 ' (see dashed border and 2 and 3 ).

The geometry is surrounded by a construction area 4 , The geometry elements 2 are all in the design area 4 arranged. The construction area 4 preferably designates a surface on a model substrate 1' about the workpiece in the computer-aided design, for example by CAD, for a subsequent additive manufacturing process of the workpiece 100 ' , with a substrate (see reference numeral 1 in 3 ) or can be made on it. The substrate then preferably corresponds to the model substrate 1' of the design or CAD model.

In the case of the SLM method, for example, the workpiece is connected to the substrate in a material-locking and / or metallurgical manner.

The variety of geometry elements 2 out 1 preferably provides a data model for a plurality of contact features 7 (compare reference numbers 7 in 3 ) for the contact structure. Each of the contact structure elements 7 is preferably over a contact surface 3 with a substrate (cf. 2 or 3 ) connected.

Furthermore, in 1 a workpiece area 5 indicated by way of example. The workpiece area 5 marks a possible dimension or contour of the workpiece to be produced additively 100 ' , The construction area 4 for example, lies completely within the workpiece area in the view shown 5 ,

2 shows a schematic sectional or side view of a model, for example, a design model of the additive to be produced workpiece 100 ' or the additively produced workpiece 100 ,

Based on 1 and 2 For example, it can be seen that the sum of the surface areas of the contact surfaces 3 preferably by a multiple, for example, five times, ten times, twenty times or even smaller than the surface area of the construction area 4 , This makes it possible, in particular, for an additively produced workpiece to be easily removed from the substrate after it has been produced or assembled 1 . 1' can be separated.

Appropriate surface areas or dimensions of the contact surfaces are either known to a person skilled in the art or are disclosed to him without inventive step by means of a design program and / or a finite element analysis of the prior art.

The contact structure 6 is for a subsequent, ie after the additive production, easy detachment of the workpiece 100 from the substrate 1 intended. About the individual geometric elements 2 or contact structure elements 7 fractures or fractures are defined or provided which, for example, are simply broken manually and / or by force after the additive preparation, and the additive-produced workpiece is thus easily removed from the substrate, for example by cutting 1 can be separated.

This technique offers an advantage, at least for relatively small workpieces to be produced additively, such as burner nozzles of gas turbines, so that complex machining processes for releasing or separating the workpiece 100 From the substrate at least for the most part can be dispensed with.

The contact structure 6 is on the substrate 1 . 1' arranged or modeled. The partially illustrated workpiece to be produced 100 ' is on the substrate 1 . 1' and immediately on the indicated contact structure 6 arranged or modeled. The contact structure 6 includes serrated, toothed or triangular contact structure elements 7 , The individual contact structure elements 7 have a vertical or vertical side surface and a side surface inclined relative to a vertical 8th on. The mentioned inclined side surfaces 8th preferably each enclose an angle α greater than or equal to 45 ° with a surface of the substrate 1 . 1' one.

Deviating from the representations of 2 and 3 can all the side surfaces 8th the contact structure elements 7 have a slope to the vertical.

Such a configuration is particularly useful for the additive manufacturing of the workpiece 100 . 100 ' because, for example, contact structure elements, which enclose a smaller angle with the substrate surface, can be made poorly or hardly additively. The reasons for this can be too poor heat dissipation and / or poor support in the powder bed, for example in the SLM process.

For those areas of the workpiece 100 , which - according to the individual geometry of the component - in any case an acute angle, ie an angle equal to or greater than 45 °, with the substrate or its surface, preferably no separate contact structure needs to be modeled.

3 shows a schematic sectional or side view of a workpiece 100 which is on the contact structure 6 is produced additive or has been or can be produced. Furthermore, in 3 the workpiece area 5 shown. At the workpiece area 5 it is the real dimension of the workpiece 100 , At the right edge of the workpiece 100 a region of the same is shown for which no contact structure has been modeled since this region is not for direct contact with the substrate 1 was provided. Only those surfaces or parts of the workpiece 100 which are to be connected directly and / or materially connected to the substrate are provided by the described method with a contact structure or modeled accordingly.

As an example, an angle α is drawn in again, which, as described above, is preferably also greater than or equal to 45 ° for all contact structure elements 7 is.

4 FIG. 12 shows a schematic flow diagram of an additive manufacturing method that includes the described method for modeling the contact structure.

The method for modeling the contact structure 6 comprises in a first method step V1 the detection of a construction area 4 for the additive to be produced workpiece on a model substrate 1' ,

Furthermore, the method for modeling, preferably in a second method step V2, comprises the acquisition of design parameters for the workpiece to be produced additively. The consumption parameters are preferably material parameters for the substrate and / or the workpiece to be produced additively 100 . 100 ' , For example, the design parameters include information about the corresponding materials. The design parameters may in particular be the (material-dependent) coefficient of thermal expansion, the thermal conductivity, the heat capacity, the mass density, the modulus of elasticity or other parameters of the substrate 1 and the workpiece 100 . 100 ' act. Furthermore, the design parameters may include process parameters of any kind.

The method for modeling the contact structure 6 furthermore comprises - in a method step V3 - the creation of the described geometry in the construction area 4 depending on the mentioned design parameters. The geometry is preferably calculated such that a workpiece produced on a substrate corresponding to the model substrate is produced in an additive manner 100 ' as indicated above by dicing, ie manual breaking and preferably without machining processing subsequently from the substrate 1 can be separated.

According to the described method for modeling the contact structure 6 , Become a variety of different geometries for different contact structures 6 and then output or display the various geometries to a user. Preferably, the user can then choose between the different geometries (see method step V4). Preferably, the user can also choose between different geometry parameters which are given to the user or a user in the context of the Calculation or modeling of the contact structure 6 can be output or displayed. For example, the user may use these geometry parameters (compare dimensions a, b in FIG 1 ) edit and / or modify, for example, to meet individual requirements of the component.

The geometry or the plurality of geometries for the contact structure is preferably calculated in the context of the method of modeling such that a connection between the substrate and the workpiece to be produced thereon additively (cf. 2 ) Stresses that arise during manufacture, withstands. Such voltages may be typical thermo-mechanical stresses which, for example, occur in the SLM process due to the large temperature gradients (eg of 1000 K / s and more). The tensions are caused in particular by the rapid heating and the rapid subsequent solidification of the built-up material.

If, due to an input or selection of the design area, due to the choice of the design parameters and / or due to the geometry parameters edited or changed by the user or user of the method, said connection fails, the described method may advantageously issue a warning to the user ( see method step V4). As a result, at least the calculation of the method for modeling or else the entire method is expediently carried out again.

The voltages mentioned are preferably calculated and / or simulated using finite element analysis (FEA). This can be done by means known to those skilled in the prior art. In particular, residual stresses of the component, for example, with a lower limit for the surface area of the contact surfaces 3 be calculated by FEA (step V4).

The process steps described under V4 are, as indicated by the dashed line in the figure, preferably as advantageous or optional and not necessarily to be considered essential.

The method of modeling further comprises the additive manufacturing method described with reference to method steps V5, V6 and V7:
Method step V5 designates the computer-aided design of the workpiece to be produced additively, preferably after, in the context of the method for modeling, the at least one geometry for the contact structure 6 created and / or calculated. Furthermore, the additive manufacturing method, for example in method step V6, comprises the additive production of the workpiece 100 . 100 ' on the substrate 1 based on the modeled contact structure 6 , Before the additive manufacturing of the workpiece 100 ' . 100 , can the contact structure 6 preferably also produced additively.

Furthermore, the additive manufacturing method preferably comprises separating the workpiece and or the component from the substrate by dicing or manual breaking (method step V7).

The present invention further comprises a computer-readable medium, for example a storage medium, such as a hard disk and / or another data memory comprising executable program instructions, which are suitable, a data processing device (not explicitly identified here) the steps described, that is, the described detection of the construction area 4 and the design parameter as well as the creation of the at least one geometry.

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

• WO 2015/106020 A1 [0002]

Claims (15)

Method for modeling a contact structure ( 6 ) in the computer-aided design of an additively manufactured workpiece ( 100 ), the method comprising the following steps: - detecting a construction area ( 4 ) for the additive to be produced ( 100 ) on a model substrate ( 1' ), - acquisition of design parameters for the additive to be produced workpiece ( 100 ' ) and - creating at least one geometry for the contact structure ( 6 ) in the construction area ( 4 ) and depending on the design parameters, wherein the at least one geometry is calculated such that one on a model substrate ( 1' ) corresponding substrate ( 1 ) additively produced workpiece ( 100 ) by dicing the substrate ( 1 ) can be separated. The method of claim 1, wherein the at least one geometry for the contact structure ( 6 ) is calculated such that the geometry has a multiplicity of geometric elements ( 2 ) for a plurality of contact structure elements ( 7 ) of the contact structure ( 6 ), and wherein each contact structure element ( 7 ) via a contact surface ( 3 ) with the substrate ( 1 ) connected is. Method according to claim 2, wherein the contact surfaces ( 3 ) are rectangular, square, polygonal, circular and / or oval shaped. Method according to claim 2 or 3, wherein the sum of the surface areas of the contact surfaces ( 3 ) is many times smaller than an area of the construction area ( 4 ). Method according to one of claims 2 to 4, wherein the at least one geometry for the contact structure ( 6 ) is calculated such that the contact structure elements ( 7 ) each have an angle (α) greater than or equal to 45 ° with a surface of the substrate ( 1 ) lock in. Method according to one of the preceding claims, wherein a plurality of different geometries for different contact structures ( 6 ) and the various geometries are then output to a user and the user can choose between the different geometries. Method according to one of the preceding claims, wherein the at least one geometry of the contact structure ( 6 ) is output to a user after computation, and wherein geometry parameters can then be edited by the user. Method according to one of the preceding claims, wherein the at least one geometry of the contact structure ( 6 ) is calculated such that a connection between the substrate ( 1 ) and the workpiece to be produced thereon ( 100 ) Stresses that arise during manufacture, withstands. Method according to claim 8, wherein the user is warned of a signal due to the calculation of the at least one geometry when a connection between the substrate ( 1 ) and the workpiece to be produced thereon ( 100 ' ) the stresses created during additive manufacturing due to the choice of design area ( 4 ) and / or the design parameter does not withstand. Method according to one of the preceding claims, wherein in the calculation of the at least one geometry stresses, which during a production of the additive to be produced workpiece ( 100 ' ) are calculated using a finite element analysis. Method according to one of the preceding claims, wherein the design parameters material information of the workpiece to be manufactured additive ( 100 ' ) and material information of the substrate ( 1 ). Additive manufacturing method of a workpiece ( 100 comprising the modeling method according to any one of the preceding claims, further comprising the steps of: - computer assisted designing of the additively manufactured workpiece ( 100 ' ), - additive manufacturing of the workpiece ( 100 ) on the substrate based on the modeled contact structure ( 6 ).  The additive manufacturing method according to claim 12, wherein after the additive production, the workpiece is separated from the substrate by dicing. An additive manufacturing method according to claim 12 or 13, wherein the contact structure ( 6 ) is first produced additive and the production of the workpiece ( 100 . 100 ' ) on the contact structure ( 6 ) he follows. Computer-readable medium comprising executable program instructions which are suitable for having a data processing device carry out the following steps: - detecting a construction area ( 4 ) for the additive to be produced ( 100 ' ) on a model substrate ( 1' ), - acquisition of design parameters for the additive to be produced workpiece ( 100 ' ) and - Create at least one geometry for the contact structure ( 6 ) in the construction area ( 4 ) and depending on the design parameters, wherein the at least one geometry is calculated such that one on a model substrate ( 1' ) corresponding substrate ( 1 ) additively produced workpiece ( 100 ) by dicing the substrate ( 1 ) can be separated.

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