EP3387565A2

EP3387565A2 - Method and device for examining an input data set of a generative layer building device

Info

Publication number: EP3387565A2
Application number: EP16815778.2A
Authority: EP
Inventors: Vincent ANTOINE; Andreas KAHLER; Christoph Mair
Original assignee: EOS GmbH
Current assignee: EOS GmbH
Priority date: 2015-12-11
Filing date: 2016-12-09
Publication date: 2018-10-17
Also published as: WO2017098003A2; US20180349530A1; US20210346957A1; WO2017098003A3; US11110517B2; CN108701162A

Abstract

The invention relates to a computer-assisted method for examining an input data set of a generative layer building device, comprising at least the following step: - comparing at least one parameter value in a computer-based model of an object that is to be produced using said generative layer building device, to a limiting parameter value which is an extreme value for the parameter able to be obtained in a method for producing the object, and particularly an extreme value for the parameter that can be obtained in a process-stable manner.

Description

ASSAYS AND DEVICE FOR CHECKING AN INPUT DATA SET OF GENERATIVE LAYERING DEVICE

The invention relates to a method and a device for testing an input data set of a generative layer construction device as well as to a generative layer construction device which is suitable for carrying out the layer construction method.

Generative layer construction processes, such as, for example, laser sintering or melting or stereolithography, are outstandingly suitable for the production of components with complex geometries, and in particular also for the production of components which are individually tailored to a particular user or for a specific application. The components are thereby produced in layers, that is, the component is formed by stacking of cross sections of the component. Thus, during the manufacturing process, cross section is formed for cross section and the individual cross sections are connected to the underlying and overlying cross sections.

In order for a component to be fabricated by a generative layering device, data must be provided to the device that includes a 3D CAD model (ie, generally a computer-based model) of the component. The design of such a CAD model is usually in the hands of a development engineer who is skilled in the art to which the component is associated and who has a thorough knowledge of the environment of use of the component and the technical characteristics that it is intended to have , In the following, such a person skilled in the art is referred to as "CAD Designer".

Although there are great freedoms in the design of a component in generative layer construction methods compared to other methods, nevertheless there are nevertheless technological constraints that prevent the production of any designs. The knowledge of whether or not a specific design, which is available as a CAD model, can or can not be produced by means of a generative layer construction process (also referred to as additive manufacturing process) is generally the responsibility of the specialists involved in generative production and hereinafter referred to as "AM experts". The knowledge of whether or not a special design can be produced usually requires detailed knowledge and often a generative experience accumulated over a longer period of time

Layer manufacturing. Because the specialized knowledge of constraints in component manufacturing typically will not be available to CAD designers, designing a model of a manufacturable component requires intensive communication between CAD designers and AM experts, which delays the design process and resources binds. Further, under some circumstances, only prototypes of one component may be manufactured with a generative layering apparatus and the subsequent series production then takes place by means of another method (e.g., CNC milling or injection molding). These subsequent methods also have special boundary conditions that must be taken into account when designing a component, so that it does not have to be changed again during the transition from prototype design to series production.

Also independent of a series production by means of other production methods (ie non-generative layer construction method), there are also subsequent production steps by means of a generative layer construction process, which can lead to limitations in the design of the model. For example, the cleaning of laser sintered parts after the production process is often done by one Blasting process to remove adhering powder on the component. The effectiveness of such a cleaning process is dependent on the component geometry. Removal of adhering powder from intricately shaped cavities, for example, can be very difficult and may not be feasible at all by the blasting technique. Especially in medicine or air and

Space used dirty components could have serious consequences. In view of the above-described problems, it is therefore an object of the present invention to provide an improved method and an improved apparatus by means of which the design of a component to be produced by means of a generative layer construction method and, if appropriate, subsequent method can be simplified or shortened.

The object is achieved by a method according to claim 1, a test apparatus according to claim 18, a generative layer building apparatus according to claim 23 and a computer program according to claim 24. Further developments of the invention are given in the dependent claims. Here, features mentioned in the dependent claims and in the following description in connection with a claim category can also be used to further develop the objects of any other claim category, unless the contrary is explicitly mentioned.

The method according to the invention is a computer-aided method for checking an input data record of a generative layer building apparatus comprising at least the following step:

Comparison of at least one parameter value in a computer-based model of an object to be produced by the generative layer construction device with a limit parameter value which is an extreme value for the parameter which can be realized in a method used in the production of the object, in particular a parameter that can be realized in a process-stable manner for the parameter ,

An input data set for a generative layer building apparatus essentially comprises a computer-based model of an object to be produced with the generative layer building apparatus. In this case, the method according to the invention can make use, for example, of a database for the comparison of parameter values in the computer-based model with limit parameter values, in which limit parameter values are stored for a method used in the production of the object, that is to say parameter values that can just be achieved by means of this method. A method used in the production of the object can be the generative layer that can be carried out by means of the generative layer construction device

Layering method or a Herstellverfaliren of the object on a device other than the generative layer building apparatus or a post-processing method, such as a surface processing method, in particular also a cleaning method. A method step is considered in particular as a sub-step in the production of the object, if no meaningful use of the object according to the intended use is possible without this method step. If, for example, the object is a jewelery item, then it can be assumed that no meaningful use is possible without a cleaning of the item after the manufacturing process.

The computer-based model is typically a 3D CAD model of an object to be manufactured. The model can also be in STL format or

Include layer information about the individual layers in the intended manufacturing process by a generative layer construction process.

In the context of the method according to the invention, at least one parameter value from the computer-based model is used for a comparison with a limit parameter value of a method used in the production of the object. This limit parameter value refers to the process stability of the process, i. H. it represents a limit beyond which it can no longer be guaranteed that by means of the method the object to be produced is process-stable, i. without the occurrence of Prozessirregularitäten, can be produced.

Thus, it is not primarily the question of whether the object to be produced represented by the computer-based model can be produced at all, but whether the manufacturing process can be reliably performed, even on the basis of the parameter value specifications from the computer-based model.

For example, if the method is laminar generative fabrication in a layered fashion of a metal object using a given generative layering device, the following may be considered: for certain dimensions (particularly wall thicknesses or the like) of the metal object, it may change during the manufacturing process due to temperature changes In the metal object, a component distortion occurs, which might have no negative effects on the metal object itself after completion of the manufacturing process. Nevertheless, such a delay can cause the manufacturing process itself to be unstable becomes. Thus, for example, a coater in a powder-based layer building apparatus when applying a next powder layer, the collision-free part of the previously produced partial metal object is no longer run over collision-free, but abuts locally on it. This can cause further distortion or superficial damage to the coater or metal object; in extreme cases, it can lead to the production process being interrupted and even interrupted.

Thus, the concept of process-stable production refers to whether a method with respect to the at least one parameter value in the computer-based model reaches its production limits (ie, exceeds or falls short of the respective limit parameter value). In fact, in such a case, there is no guarantee that the planned object can be manufactured safely (ie process-stable) by means of the method.

According to the invention, therefore, based on the parameter value information from the computer-based model, not only a statement about the properties of the produced object is made, but a statement about the process stability of the manufacturing process of the object is made.

Preferably, the inventive method further comprises the step of outputting information to a user in the event that the result of the comparison is that the parameter value is beyond the extreme value.

As a result, the CAD designer can be provided with immediate information during the creation of a design as to whether the design meets all requirements for process-stable production, which makes time-consuming consultations with AM experts unnecessary.

Usually, but not exclusively, the parameter taken into consideration will be one dimension. In this case, checking whether a process stability limit is exceeded is very simple.

The limit parameter value is preferably an extreme value for the parameter which can be produced by means of the generative layer construction device, in particular a the generative layer construction device process stable produced extreme value for the parameter.

The review of potential process instabilities or vice versa the verification that on the basis of the computer-based model process stability in the production of each object to be manufactured can be assumed, in particular a comparison of several parameter values from the computer-based model, which are respectively assigned to different parameters, with the corresponding limit parameter values. In particular, limit parameter values may also be extreme values for a parameter that can just be produced by means of the generative layer building apparatus, i. in principle, are feasible. If a parameter value from the computer-based model is not feasible in principle, then certainly no process-stable realization of this parameter is possible. In contrast to this, as already mentioned, even if the parameter value can in principle be realized in principle, it is not inevitable that there will also be process-stable manufacturability.

In particular, the generative layer construction device may be a very specific generative layer construction device, which is characterized as follows:

A very specific generative layer construction device, characterized by a serial number, this layer construction device being, for example, specifically optimized,

A very specific series of generative layer construction devices, e.g. all devices with the type designation "EOS P390",

A group of generative layer building devices (which may well have come from different manufacturers) that share a common characteristic (e.g., a minimum space size, etc.),

Generative layer construction devices designed to process a specific group of materials (e.g., plastic or metal, possibly even further)

, restricted to e.g. PA12)

• Generative layer building devices that are a very specific type of generative Perform layering processes (eg stereolithography devices or SLS (selective laser sintering devices))

Depending on which boundary parameters are used as a basis for the comparison, this determines for which "specific generative layer construction device" the comparison is carried out. Thus, if boundary parameter values relating to a particular group of generative layer construction devices are involved, then the comparison of the respective parameter value with a marginal parameter value is checked for devices of this group of generative layer construction devices.

In the context of the method according to the invention, therefore, at least one parameter value from the computer-based model is used for a comparison with a limit parameter value of the particular generative layer building apparatus. This limit parameter value relates to the process stability of the particular generative layer building apparatus, i. h, it represents a boundary beyond which it can no longer be guaranteed that this particular generative layer building device is process stable, i.e., stable, for the object to be manufactured. without the occurrence of process irregularities, can produce.

According to the invention, therefore, based on the parameter value information from the computer-based model, it is not (only) a statement about the properties of the manufactured object that is made, but a statement about the process stability of the manufacturing process of the object is made.

If, in the following, parameters and (limit) parameter values are mentioned, this can refer both to the parameter values with regard to the process stability of the layer building apparatus and to those with regard to the above-mentioned basic manufacturability.

Limit parameter values predetermined by a generative layer construction method preferably comprise at least a minimum wall thickness, a minimum hole diameter, a minimum blind hole width and / or a maximum blind hole depth, a minimum hole width and / or depth, in particular a minimum slot width and / or depth, a minimum by the generative Schichtbauvorrichtung producible detail resolution, a minimum step offset extending obliquely to several layers a maximum wall thickness or a user specified by a user parameter, in particular depending on the underlying data to a provided for the production of the object material and / or command parameters and / or wall thicknesses.

The above-mentioned parameters, individually or in combination, usually describe the performance of a generative layer building apparatus. For example, a minimum hole diameter will depend on how strong the heat conduction in the build material used is, such as a beam diameter of a laser beam used for solidification, etc. In particular, the boundary parameters may depend on the command parameters used for the control of the generative layer building apparatus, for example, by determining the order in which the individual points of an object cross-section are solidified. Preferably, in the event that the result of a comparison is that a parameter value is beyond a corresponding limit parameter value, an adaptation of this parameter value is carried out automatically and / or in interaction with a user. This further simplifies the creation of a suitable computer-aided model for the CAD designer. Through interaction with the CAD designer, this is either guided to a design that can actually be produced, or else the CAD designer does not have to worry about the manufacturability and machinability of the component and the process stability of the operation of the generative layer building apparatus designed model of the component is automatically corrected. When adjusting a parameter value, especially when automatically adjusting it, the parameter value can be set to the limit parameter value. In this approach, the performance of the generative layer building apparatus is fully exploited. If the limits of manufacturability or process stability are not to be addressed, this can be achieved by correspondingly mitigated limit parameter values. In the adaptation, in particular in the case of automatic adaptation, the parameter value can be further modified in such a way that a mechanical property of the manufactured object is modified in a predetermined direction. This makes it possible not only to consider given limits of manufacturability of a component, but at the same time also set desired physical properties of the manufactured component, in particular automatically.

In the adaptation, in particular in the automatic adjustment, for example, a parameter value can be changed so that the weight of the manufactured object is reduced. This can be done, for example, by thinning struts in a lattice structure or by enlarging cavities or by inserting them into the object or else by normally producing massive areas of the building component with a structure inside. For example, in the adaptation, in particular in the automatic adjustment, the parameter value can be modified so that the stiffness and / or tensile strength and / or elongation at break and / or the transverse contraction number and / or the torsional behavior and / or the fatigue behavior of considered object and / or modified, in particular optimized, is. The above procedure makes the design even easier for the CAD designer since the method optimizes important mechanical parameters of a component based on the current design already at the time of the design. As a result, the development period for a component can be reduced. For example, during the adaptation, in particular during the automatic adaptation, of a parameter value, the change in the parameter value can be determined on the basis of a finite element simulation of a mechanical property of the object to be produced. In this case, information about the material composition of the component, in particular mechanical and physical parameters of the material, ideally flows into the simulation.

Furthermore, in the case of a method according to the invention, if the production of the object by means of the generative layer building apparatus involves a first production method the limit parameter value may be an extreme value for the parameter that can be produced by means of a second production method other than the first production method, and / or an extreme value that can be processed for the parameter in a method following the first production method.

The limit parameter values may in this case relate to a specific post-processing device or second production device (for example a mass-produced device), in other words parameter values which can just be processed by means of this post-processing device or produced by this second production device.

The term "certain finishing device or second manufacturing device" may denote the following different types of devices:

A very specific device, characterized by a serial number which, for example, is specifically optimized,

• a very specific series of devices, e.g. all devices of the same series with the same type designation,

A group of devices (which may well have come from different manufacturers) which share a common characteristic (e.g., a minimum space size or the use of the same abrasive, etc.),

• Devices that are designed to process or process a particular one

Group of materials (e.g., plastic or metal, possibly further limited to, for example, PA12),

Manufacturing devices that perform a very specific type of manufacturing process (for example, injection molding equipment, CNC milling equipment or SLS (selective laser sintering equipment))

Depending on which limit parameters are used as a basis for the comparison, this determines for which "specific post-processing device or second production device" a workability or producibility is checked. So if it is border parameter values that relate to a particular group of devices, then the machinability of a component (object) by means of a device from this group of devices tested.

Boundary parameter values predetermined by a post-processing method or second production method preferably comprise at least one of the following: a minimum wall thickness, a minimum hole diameter, a minimum blind hole width and / or maximum blind hole depth, a minimum hole width and / or depth, in particular a minimum slot width and / or depth, a minimum processable by the device used in the downstream process and / or the second device producible detail resolution, a minimum step offset at obliquely extending to multiple layers surfaces, a maximum wall thickness or predetermined by a user user parameter, in particular depending from underlying data to a material provided for the first and / or second manufacturing method material and / or command parameters and / or wall thicknesses.

The above parameters, individually or in combination, typically describe the performance of a post-processing device or the second manufacturing device (e.g., a mass-produced device). For example, a minimum hole diameter will depend on how strong the heat conduction is in the build material used, such as e.g. a beam diameter of a laser beam used for solidification, etc. In particular, the limit parameters may depend on the type of control of the post-processing device or second manufacturing device.

The limit parameter value may, for example, be a minimum value for a dimension determined by a method for the treatment of the surface, in particular a

Method for cleaning the surface of the object, in particular after its preparation is machinable. Since generatively manufactured components are in many cases surrounded by build material during their manufacture, cleaning is an important step required in many manufacturing processes. A corresponding consideration according to the invention of the performance of the cleaning process already during the design of a component is important, since it depends on clean component surfaces in many applications. It is conceivable, however also consideration of limit parameter values for other surface treatment methods, eg inking methods. In the latter case, a limit parameter value could be, for example, the minimum diameter of a hole to be inked in the surface. In particular, the threshold parameter value may be a minimum value for a dimension that can be processed by a method for blasting the surface of the object after its production. This makes it possible, especially in blasting processes that are frequently used for component cleaning, to gain insights into its machinability already during the design of the component.

If the radiopacity of its surface is already checked during the design of a computer-based model of the object to be manufactured, this can be done by checking for at least a portion of the surface whether it is another in a direction of a normal to the surface Surface portion of the object and, if so, the distance in the direction of the normal between the at least a portion of the surface and the further surface portion is compared with the limit parameter value.

By means of this modification of the method according to the invention, it is possible in a particularly simple manner to determine the radiopacity of a component to be produced on the basis of a computer-aided model even before production. This saves unnecessary manufacturing operations that lead to unusable components, as a sufficient cleaning is not possible. Furthermore, as an alternative or in addition to the method just described, the radiopacity of the surface of the object to be produced can also be checked by checking, for at least a portion of the surface, whether it is within an angular range which includes a direction of a normal to the surface spaced a portion of the surface gives a further surface portion of the object and if so, the distance between the at least a portion of the surface and the further surface portion is compared with the limit parameter value. This specific procedure makes it possible to check even more selectively a surface's radiotranslucency, since more complex geometries of object surfaces can be taken into account when assessing the radiance. Specifically, by adjusting the angle range to be based on the test, the method can be adapted to different blasting methods (for example, to the size of the grains used in blasting).

A generative layer construction method according to the invention for producing at least one three-dimensional object by means of layered solidification of a powdery or liquid building material is carried out in a generative layer construction device

a construction substrate for supporting the at least one object to be produced, an application device for applying a layer of the pulverulent or liquid building material to the construction substrate or a previously applied and selectively consolidated layer of the construction material,

a selective solidification device capable of acting on all locations in the applied layer corresponding to a cross section of the at least one object to be manufactured, such that the building material bonds to a solid at those locations, and

a control unit which controls the application device and the selective solidification device such that the object is produced by successive selective solidification of layers of the construction material,

According to the invention, an input data record which has been tested by means of the previously described inventive method is used to control the layer construction method.

A test device according to the invention for testing an input data set of a generative layer construction device comprises:

a comparison unit which compares at least one parameter value in operation in a computer-based model of an object to be produced by the generative layer construction device with a limit parameter value, which is an extreme value for the parameter which can be realized in a method used in the production of the object, in particular a process-stable, realizable extreme value for the parameter,

optionally a storage unit in which a computer-based model of an object to be produced by means of the generative layer building apparatus is stored, optionally a memory unit in which at least one limit parameter value is stored, which is an extreme value for the parameter that can be implemented in a method used in the production of the object, in particular a process-stable, realizable extreme value for the parameter.

A test device according to the invention for testing an input data set of a generative Schichtbauvomchtung comprises:

a comparison unit which, in use, compares at least one parameter value in a computer-based model of an object to be produced by the generative layer construction device with a limit parameter value of the layer construction device, which is an extreme value for a parameter which relates to a process-stable production of the object to be manufactured, optionally a storage unit in which a computer-based model of an object to be produced by means of the generative layer building apparatus is deposited and optionally a storage unit in which at least one limit parameter value of the laminating apparatus is stored, which is an extreme value for a parameter that is based on a process-stable production of the item to be produced Object refers.

In a variant of the test apparatus, the comparison unit carries out a comparison with a limit parameter value, which is an extreme value for the parameter that can be produced by the generative layer construction device, in particular an extreme value for the parameter which can be produced by the generative layer construction device in a process-stable manner.

In the case of the test apparatus, the comparison unit may also perform a comparison with a limit parameter value which, if the production of the object by means of the generative layer construction apparatus is a first production method, can produce an extreme value that can be produced by means of a second production method other than the first production method for the parameter is and / or is a processable in a first manufacturing process processable extreme value for the parameter. The test device according to the invention thus allows a reduction in the time from the beginning of the design of a computer-aided model of a component to completion and if necessary, cleaning of the component after a generative layering process or, if necessary, until completion of the component in a mass production process. The test device may be, for example, an independent device that may be integrated into a network or else integrated into an existing computer aided design (CAD), computer aided engineering (CAE), or computer aided manufacturing (CAM) system , Optionally, the test apparatus may include an output device which, in the event that the result of the comparison is that a parameter exceeds or falls short of a parameter threshold, outputs a corresponding information to a user. Instead of (or in addition to) the respective above-mentioned memory units, the corresponding data (computer-based model or limit parameter value) can also be fed to the test apparatus via at least one input interface designed to receive this data.

Even if in principle an automatic design adaptation by the testing device is possible, it is sometimes more comfortable for the user of the testing device (eg a CAD designer) if he himself can prescribe by means of specifications on an input device (eg a terminal) in which way his planned design is adjusted. Therefore, the inventive testing device may optionally include an input device for manipulating the computer-based model by a user.

If the marginal parameter values and the computer-based model of the component to be produced are stored in one and the same memory device, this speeds up the performance of the method, since this prevents time losses due to long transmission paths of the data. The memory device can either be contained in the test device according to the invention or else the latter can access the memory device (possibly via a network).

A generative layer construction device according to the invention for producing at least one three-dimensional object by means of stratified solidification of a powdered or liquid construction material has the following merlanals:

a building pad for supporting the at least one object to be produced, an application device for applying a layer of the powdery or liquid building material to the construction substrate or a previously applied and selectively consolidated layer of the construction material,

a selective solidification device capable of acting on all the locations in the applied layer corresponding to a cross section of the at least one object to be manufactured, such that the building material bonds to a solid at those locations, and

a control unit which controls the application device and the selective solidification device so that the object is produced by successive selective solidification of layers of the construction material,

wherein the generative layer construction device according to the invention has in particular a test device according to the invention for testing an input data set of a generative layer construction device and / or is connected by signal technology to such a test device.

If the test device for testing an input data set of a generative layer construction device is contained in or connected to the latter, alternatively or additionally to the adaptation of the design to the process stability and, if applicable, additionally manufacturability during the design of a computer-aided model of a component to be produced, Also immediately before the start of a manufacturing process by an AM expert, the process stability and possibly additionally the manufacturability are checked. On the one hand, such a review serves to avoid unstable manufacturing operations leading to unusable parts, which is wasteful of time and resources, and on the other hand, it makes it easier for the AM expert to verify process stability, as it allows compliance with marginal parameter values Design does not have to "manually" debug, which avoids errors on its part in checking process stability.

The inventive method is expediently realized in the form of a computer program, even if this is not absolutely necessary. However, a software-supported implementation of the method allows easy integration into a CAD, CAE or CAM System or a generative layer construction device. The software can for example be stored in a memory of the CAD, CAE or CAM system or the generative layer construction device or the CAD, CAE or CAM system or the generative layer construction device can access the software via a network,

Further developments of the invention are specified in the subclaims. In this case, features of the dependent claims and the following description of the method according to the invention can also be used to further develop the device according to the Invention or vice versa, unless this is explicitly excluded.

Fig. 1 shows a schematic representation of a generative layer building apparatus on

Example of a laser sintering device.

Fig. 2 shows a schematic representation of a method according to the invention for

Examination of an input data set for a generative layer construction device and

Fig. 3 shows the structure of a test apparatus according to the present invention.

Fig. 4 shows schematically the procedure in an embodiment of a method for verifying the radiopacity of a surface.

FIG. 5 shows by way of example a correction of the surface geometry for the production of the

Strahlbarkeit.

Fig. 6 shows schematically the procedure in a further embodiment of a method for verifying the radiopacity of a surface.

For a description of the method according to the invention, a generative layer construction device according to the invention will first be described below with reference to FIG. 1 using the example of a laser sintering apparatus. The device has a building container 1, in which a support 2 is provided for supporting an object 3 to be formed. The carrier 2 can be moved in the building container via a height adjustment device 4 in the vertical direction. The plane in which applied powdered building material is solidified defines a working plane 5. For solidifying the powdery material in the working plane 5, a laser 6 is provided which generates a laser beam 7, which via a deflection 8 and optionally a focusing 9 the working level 5 is focused. A control 10 is provided, which controls the deflection device 8 and optionally the focusing unit 9 in such a way that the laser beam 7 can be directed to any desired position of the working plane 5.

The controller 10 is controlled via a control instruction set, which i.a. Contains data containing the structure of the object to be manufactured, in particular a three-dimensional CAD layer model of the object with information about the respective cross-section of the object in each layer of the building material to be solidified, and data defining the precise parameters in solidifying the building material. In particular, the data contains accurate information about each layer to be consolidated in the manufacture of the object.

Further, a supply device 1 1 is provided, can be supplied with the powdered building material for a subsequent layer. By means of a coater 12, the building material is applied and smoothed in the working plane 5.

During operation, the carrier 2 is lowered layer by layer by the controller 10, the coater 12 is actuated to apply a new powder layer and the deflection device 8 and optionally also the laser 6 and / or the focusing unit 9 for solidifying the respective layer on the respective object corresponding points by means of the laser beam

7 in the working level 5 driven.

As a powdery building material, all suitable for the laser sintering powder or powder mixtures can be used. Such powders include, for. As plastic powder such as polyamide or polystyrene, PAEK (polyaryl ether ketones), elastomers such as PEBA (polyether Block Ami de), plastic-coated sand, ceramic powder or metal powder, z. As stainless steel powder or other, adapted to the particular purpose metal powder, in particular alloys. The procedure according to the invention will be described below with reference to FIGS. 2 and 3.

First, the model data input unit 101 in the test apparatus 100 according to the invention for checking an input data set of a specific generative layer construction device (CAD) model data MD of the component to be produced, which describe at least a portion of the component to be produced (step Sl in Fig. 2). , The data MD may also include information about the individual layers during the generative manufacturing process. In addition, further information, for example about the materials to be used, may be included. If the test apparatus is not integrated into the CAD design system with which a CAD designer designs a component to be manufactured by a generative manufacturing method (eg as a plug-in), the data MD originating from the CAD design system may be the model data - Input unit 101 are supplied either via a network or read via a mobile data carrier in the model data input unit 101. If the test apparatus 100 is part of the CAD design system, the model data input unit 101 can easily access the location of the data within the design system. Optionally, the model data MD can be stored in a memory unit 103b contained in the test apparatus 100. Now parameter values PI... Pn in the model data MD are determined by means of the parameter determination unit 102, which correspond to parameters for which limit parameter values GP1 to GPn are predetermined (step S2 in FIG. 2). Boundary parameter values GP1 to GPn are extreme values for parameters of the layer-building apparatus that relate to a process-stable production of the object to be manufactured or extreme values for parameters that are used in a method for finishing at least a part of the surface of one by means of generative

Laminated device manufactured object, z. B. a cleaning process, are just editable and / or parameters in the production of the object by another Device as the generative layer building device are just to produce. By way of example, the other device may be an injection molding device used for mass production of the components after first prototypes have been produced by means of the generative layer construction device. The set of limit parameter values may include only one limit parameter value PI or a plurality of limit parameter values PI to Pn. The parameters assigned to the parameter values are, for example, wall thicknesses, hole diameters or channel diameters, blind hole depths, etc. in the model data MD. The corresponding limit parameter values would then be, for example, a minimum wall thickness, a minimum hole diameter or channel diameter, a maximum bag depth, etc. In particular, parameters and limit parameter values may also relate to parameter-based aspects of a layer construction method which are not associated with a process-stable production of an object stand.

The determined parameter values PI. Pn are supplied to the comparison unit 103, which performs a comparison of each of the determined parameter values PI to Pn with the associated limit parameter value GP1 to GPn (step S3 in FIG. 2). The limit parameter values GP1 to GPn can in this case be stored in a memory unit 103a in the test apparatus 100 or, alternatively, the limit parameter values are supplied to the test apparatus 100 via a network or a mobile data carrier. It should be noted that the memory unit 2 0 103a (as well as the memory unit 103b) does not necessarily have to be part of the comparison unit 103, even if this is illustrated in FIG. 3 in this way.

If the comparison reveals that one or more parameter values exceed or fall below the associated limit parameter values (for example, below a minimum wall

2 5 thick or exceeding a maximum blind hole depth), then the process in Fig. 2 proceeds to step S4. There are several ways to do this in this step:

On the one hand, a notification unit 104 shown in FIG. 3 can inform a user about one or more limit value overruns. In this case, the user must

3 0 (e.g., a CAD designer) itself decide what to do (e.g., adapt the design or

Change to another generative layer construction device). Alternatively or additionally, the test apparatus 100 may modify the model data to modify the parameter value (s) that exceeded limits. For example, the model data may be modified so that the corresponding parameter values coincide with the respective limit parameter values. The modified model data can then be transmitted to the CAD design system via a model data output unit 105 shown in FIG. This can, for example, again be done via a network or a mobile data carrier or by accessing a storage device to which the CAD design system also has access. If the limit parameter values are not exceeded or fallen below, an optional message can be output to a user. In FIG. 2 this would be the optional step S5. If the limit parameter values are exceeded or undershot, the method can be terminated with a notification to the user when the limit is exceeded or undershot for the first time, or it can be continued until the entire model data received by the model data input unit 101 has been completely checked. In the latter case, the user would receive information about any limit parameter overruns or underruns that have occurred. Even with an automatic change of the model data MD by the test apparatus, it makes sense to check the entire model data received from the model data input unit 101.

If, for example, the minimum wall thickness that can be produced is undershot in the model, the method according to the invention can indicate to the CAD designer by means of visual information that there will be a problem in the production. The user is also preferably shown the specific position in the model at which the problem will occur. This could be done, for example, by highlighting in a visualization of the already designed model the position at which a production problem will arise. In response to the warning issued, the user can then adapt the CAD model. for example, increase the wall thickness at the designated location. For example, problems with too thin a wall thickness in the CAD model can result, for example, in a laser melting process, after the melting of the powdery building material in the region of a cross section, a thin wall in the W 201

22

Part intersects, in the region of the thin wall powder in the area adjacent to the molten area area connects so strongly with the molten area, thereby increasing the wall thickness and a minimum wall thickness can not be exceeded. A similar problem can occur when making a very small hole. Here by adhering material, the hole completely disappear, so that a minimum hole diameter can not be undershot. If the hole is not in the form of a leash, it can (for example in the case of elongated holes) correspondingly not fall below a minimum hole width. Similarly, a minimum depth of hole may be predetermined by the manufacturing process (e.g., by a gener- ous layering device) or a post-processing process. This may be due, for example, to the fact that a hole depth is less than the thickness of a layer in the layered production. Quite generally, the method according to the invention can check whether a detail which can be produced minimally by the generative layer construction device is undershot in the designed model.

Another problem is blind holes. Here it must be ensured that after the completion of the manufacturing process, unsolidified building material can be removed from the blind hole again so that it must have a minimum width and / or a maximum depth. In the case of surfaces running diagonally to several layers, there will be a step offset in the case of generative layering processes (staircase character). Here you can

CAD designers are shown, with what resolution a sloping surface can be realized, so how is the minimum feasible step offset.

In general, the information relating to the limit values which can be realized depends on the material used for the production, since different materials, for example, can behave differently during melting and, for example, conduct different heat. The parameter limit values are also influenced by the control of the production process or post-processing process, that is, for example, by the control commands or command parameters of a generative layer building apparatus used for the production. Thus, the laser beam diameter used in a laser melting device plays a role as well as the jet speed, the cooling power, the used layer thickness and possibly even the number of objects to be produced in the installation space. Again, it can be seen that the estimation of whether a component will exceed or fall short of the limit parameter values in its manufacture is a difficult task. In the worst case, the limit parameter values are long-term empirical values, which were determined, for example, on previous similar components.

For the user of the method according to the invention, it is of particular advantage if parameters or dimensions which exceed or fall short of a limit parameter value are automatically adjusted, so that the CAD model at the point at which a problem arises during production, is changed automatically. For example, a wall thickness originally measured at 100 .mu.m can automatically be set to 150 .mu.m. For example, a parameter value that exceeds or falls below a limit parameter value could automatically be set to the limit parameter value. In order to stay with the example of the minimum wall thickness, so if the Grenzparameterwert is 150 μιη, a 100 μηα measured wall automatically set to 150 μηι.

With the knowledge of the limit parameter values which are present for a generative layer building apparatus, the knowledge of the building material used and of the production parameters used generally also go hand in hand. This makes it possible to simulate its mechanical or physical properties even before the production of the actual component. This, in turn, makes it possible to make adjustments to the model already during the CAD design by which a mechanical or physical property of the component is changed in a desired direction. For example, after a simulation of the component weight, one could modify the model to reduce the weight, for example by reducing wall thicknesses. In the same way, adjustments can be made, for example, to stiffness, tensile strength, tensile elongation at break, transverse contraction number, torsional behavior or fatigue behavior. W

Ideally, adaptation of mechanical properties of the part is done automatically by adjusting the model after the CAD designer, at the start of the design, has informed the system which mechanical properties to optimize in which way.

As far as the mentioned simulation method is concerned, it is possible to resort to known finite element simulation methods for this purpose.

As already mentioned, the method according to the invention can be realized by means of a software which is executed on the CAD system. The software can be present as an additional module that interacts with the CAD program. For example, the model data may be transmitted over a common interface such as Of course, the process expedites the process when the software module according to the invention accesses the same model data as the CAD program, in other words, when both on the access same record. This also saves space in particular.

If the test device according to the invention is realized as a plug-in module for a CAD design system, then it is possible, in particular, for a check for possible limit value overruns or undershoots to be continuously made during the preparation of the design. With the addition of non-manufacturable model features (e.g., too thin a wall), the CAD designer can immediately be given feedback. Alternatively, the method according to the invention in the background (with or without information to the CAD designer) can automatically change parameter values which can not be produced by automatic modification of the design.

Regardless of the advantages conferred on a CAD designer, the inventive method can of course also run as software on a stand-alone computer system. For example, after the completion of the design of a computer-aided model of a component before the manufacture of the component, its manufacturability can be checked again. The data exchange between the CAD system and the system with the software according to the invention can take place by means of mobile data carriers or via a network. In some circumstances, the Software, with which the method according to the invention is realized, also in a directly to the generative layer building apparatus, with which the production will take place affiliated computer or run in the generative layer building device itself. Ideally, an AM expert can then make final adjustments immediately prior to the production of the component in order to avoid any difficulties in the production of the component by means of the generative layer construction device or a production by means of a device other than the generative layer construction device or one of the For the sake of completeness it should be mentioned that a data exchange with the generative layer building apparatus can also be carried out with the aid of mobile data carriers or a network.

Although only one laser sintering device has been described above as an example of a generative layer construction device, the method according to the invention can naturally also be applied to other generative layer construction devices and methods. Here, by way of example only, laser melting, LLM (cutting out of films and joining), FLM (applying a thermoplastic material from a die), 3D printing, mask sintering and stereolithographic processes are mentioned.

Furthermore, the invention is not limited to the design, manufacture and processing of a single component. If several (for example different) components are produced at the same time, then the method according to the invention can be carried out in the same way with all variants, only that then a check of the manufacturability for several components is carried out simultaneously. According to the invention, the manufacturability of the designed model in a mass production process, which is not a generative layer construction process, can also be checked, for example after initial prototypes of the component have been realized by means of a generative layer construction process. An apparatus for producing the component, which is based on the same CAD model, which is also the basis of the production by means of a generative layer building apparatus, for example, an injection molding machine, a CNC milling machine, a casting device, an extruding, etc., or even another generative piercing device than that used to make prototypes. In one embodiment of the method according to the invention, the radiopacity of the manufactured component based on a CAD model is checked. This is done before the component is produced by means of a generative layer construction device or the production by means of another device in a series production process. The procedure is explained below with reference to FIGS. 4 to 6:

First of all, the 3D CAD model has to be brought into a format in which the outer surface of the corresponding component is fixed by means of a tessellation, ie an overlapping with partial surfaces, e.g. Polygons such as triangles, squares, pentagons, etc. is described. For example, this is the case in the widely used STL format, where the surface is described by overlapping with contiguous triangles. Now, a plurality of individual polygons or patches are selected which are distributed as evenly as possible (but not necessarily) over the surface. The following procedure is now performed for each polygon:

4 shows a section through a part of the surface of a component to be radiated with a selected polygon or surface section 401. For this surface section, the center of gravity S of the surface is checked at a defined position on the surface (for example in each of the selected surface sections) whether there is a further surface portion 403 spaced from the surface portion 401 in a direction of the surface normal 402 facing out at this center of gravity. If this is the case, the distance d in the direction of the surface normal 402 between the two surface sections 401, 403 is determined and compared with a limit value (limit parameter value). If the limit value is undershot, it is determined that the irradiability of the initially selected surface portion 401 is not given. In this case, information is outputted to the user or automatic adjustment (eg, enlargement of the distance d by rotating the portion 401 in the counterclockwise direction, as indicated in FIG. 5). It should be mentioned again here that all possible variations and procedures, as described above in connection with the testing of manufacturability, are equally applicable to the present embodiment. The described procedure does not depend on the type of tessellation, in particular the shape of the surface sections. These do not necessarily have to be polygons and not necessarily all of the same kind, eg not all triangular. There are theoretically also mixtures of eg, triangles and pentagons or pentagons and circles (with intermediate forms), etc. possible.

Furthermore, it would theoretically also be possible to randomly select only a surface section 101 and to carry out the method explained in FIG. 4 thereon. As for the location of the point where the surface normal starts, within a surface section, there are no limitations therefor. In any case, it makes sense to specify the position of this point in all selected surface sections in the same way. In the case of triangular surface sections, for example, instead of the center of gravity, it would also be possible to select the point of the center of the circle or the center of circumference or another point of excellence within the area of the triangle.

A modified embodiment in which the radiopacity is checked will be described with reference to FIG. 6. According to this modification, the distance to any further surface portion at a defined position of the surface is not checked in the direction of the surface normal 402, but in the direction of at least one Beam 402 ', which includes an angle α (<90 °) with the surface normal. Preferably, such a distance d 'can also be determined for a plurality of beams 402' which are all within a predetermined angular range around the surface normal 402.

Apart from the angle different from 90 ° the other procedure (including all possible variations) is the same as above in connection with the use of the

Surface normal 402 has been described. That is, when a detected distance d 'is smaller than a threshold value, it is determined that the irradiability of the surface portion 401 is not given. One can also proceed in such a way that in the event that the limit for the distance of two

Surface sections along the surface normal 402 falls below, in addition It is determined whether the limit is also exceeded for a beam 402 ', which includes an angle α with the surface normal. Again, the test may also be performed for multiple beams 402 'within a predetermined angular range around the surface normal 402. For example, it may then be stipulated that the surface is able to be radiated whenever there is at least one beam 402 'within the angular range along which the limit value is not undershot.

The size of the angle range to be used in the latter modification is dependent on the material of the component, the blasting agent and other beam parameters. However, in the last-mentioned modification, it is possible to check the radiation in a more complex manner and to individually determine whether or not radiation is present depending on the beam parameters.

Finally, it should be mentioned that the individual components of a device for testing an input data set of a generative layer construction device can also be used alone

Hardware components or mixtures of hardware and software can be realized. The device must then have an input interface through which the CAD model data can be fed and also the limit parameter values can be supplied. Interfaces mentioned in the present application do not necessarily have to be designed as hardware components, but can also be realized as software modules, for example if the data fed in or output therefrom can be taken over by other components already realized on the same device or must be passed to another component only by software. Likewise, the interfaces could consist of hardware and software components, such as a standard hardware interface specifically configured by software for the specific application. In addition, several interfaces can also be combined in a common interface, for example an input-output interface.

Claims

1. A computer-aided method for testing an input data set of a generative layer building apparatus comprising at least the following step:

2. The method of claim 1, further comprising the step of:

- Output of information to a user in the event that the result of the comparison is that the parameter value is beyond the extreme value.

A method according to any one of the preceding claims, wherein the parameter taken into account comprises a dimension.

4. The method according to claim 1, wherein the limit parameter value is an extreme value for the parameter which can be produced by means of the generative layer construction device, in particular an extreme value for the parameter that can be produced in a process-stable manner by means of the generative layer construction device.

5. The method of claim 4, wherein boundary parameter values predetermined for a comparison of at least one parameter value in the computer-based model comprise at least one of the following:

a minimum wall thickness,

a minimum hole diameter,

a minimum blind hole width and / or maximum blind hole depth,

a minimum hole width and / or depth, in particular a minimum slot width and / or depth, a minimum detail resolution which can be produced by the generative layer construction device,

a minimum step offset at surfaces running obliquely to several layers,

a maximum wall thickness,

a user parameter specified by a user,

in particular as a function of the underlying data for a material and / or command parameters and / or wall thicknesses provided for the production of the object.

6. Method according to claim 4 or 5, wherein, in the event that the result of a comparison is that a parameter value lies beyond an associated limit parameter value, an adaptation of this parameter value is carried out automatically and / or in interaction with a user becomes,

7. The method of claim 6, wherein in the adaptation of the parameter value, in particular in the automatic adjustment of the latter, the latter is set essentially to the limit parameter value.

8. The method of claim 6, wherein in the adjustment, in particular in the automatic adjustment, the parameter value is changed so that a mechanical property of the manufactured object is changed in a predetermined direction, preferably the parameter value is changed so that the Weight of the manufactured object is reduced.

9. The method of claim 8, wherein in the adaptation, in particular in the automatic adjustment, the parameter value is modified so that the stiffness and / or tensile strength and / or elongation at break and / or the transverse contraction number and / or the torsional behavior and / or the fatigue behavior of the manufactured object are taken into account and / or modified, in particular optimized,

10. The method according to any one of claims 8 to 9, wherein in the adjustment, in particular in the automatic adjustment, the change of the parameter value is determined on the basis of a finite element simulation of the mechanical property of the object to be produced.

1 1. The method according to any one of the preceding claims, wherein, when it is in the production of the object by means of the generative layer building apparatus is a first manufacturing method, the limit parameter value by means of a second, different manufacturing method than the first manufacturing method manufacturable extreme value for the Is parameter and / or a processable in a first manufacturing process method editable extreme value for the parameter.

12. The method of claim 1, wherein predetermined limit parameter values comprise at least one of the following:

a minimum wall thickness,

a minimum hole diameter,

a minimum blind hole width and / or maximum blind hole depth,

a minimum hole width and / or depth, in particular a minimum slot width and / or depth,

a detail resolution that can be processed minimally by the device used in the downstream method and / or a detail resolution that can be produced for the second manufacturing method,

a minimum step offset at surfaces running obliquely to several layers,

a maximum wall thickness,

a user parameter specified by a user,

in particular as a function of the underlying data for a material and / or command parameters and / or wall thicknesses provided for the first and / or second production method.

13. The method according to any one of the preceding claims, wherein the limit parameter value comprises a minimum value for a dimension, which is changeable by a method for the treatment of the surface of the object, in particular after its production.

14. The method of claim 13, wherein the limit parameter value is a minimum value for a dimension that is changeable by a method for cleaning the surface of the object after its manufacture.

15. A method according to claim 13 or 14, wherein the limit parameter value is a minimum value for a dimension that is changeable by a method of blasting the surface of the object after its manufacture.

16. The method of claim 15, wherein the radiopacity of the surface of the object to be manufactured is checked by checking for at least a portion of the surface whether it is within an angular range including a direction of a normal to the surface, in particular in one direction the normal, of which at least a portion of the surface is spaced, gives a further surface portion of the object and, if so, the distance between the at least one portion of the object

Surface and the other Oberflächenabsclinitt, in particular the distance in the direction of the normal is compared with the limit parameter value.

17. Generative layer construction method for producing at least one three-dimensional object (3) by means of layered solidification of a powdery or liquid building material in a generative layer building apparatus with

a construction substrate (2) for supporting the at least one object to be produced, an application device (12) for applying a layer of the powdered or liquid building material to the construction substrate (2) or a previously applied and selectively consolidated layer of the construction material,

a selective solidifying device (6, 8, 9) capable of acting on all the points in the applied layer corresponding to a cross-section of the at least one object to be made, such that the building material bonds to a solid at those points, and

a control unit (10) which controls the application device (12) and the selective solidification device (6, 8, 9) such that the object (3) is produced by successive selective solidification of layers of the construction material,

wherein an input data set tested by means of a method according to one of the preceding claims is used to control the layering process.

18. Test device for testing an input data set of a generative layer construction device comprising: - A comparison unit (103) which compares in operation at least one parameter value in a computer-based model of an object to be manufactured by the generative layer building apparatus (3) with a limit parameter value, which is an extreme value for the parameter realizable in a method used in the production of the object , in particular a process-stable, realizable extreme value for the parameter,

optionally a storage unit (103b) in which a computer-based model of an object (3) to be produced by means of the generative layer building apparatus is stored,

optionally, a memory unit (103a) in which at least one limit parameter value is stored, which is an extreme value for the parameter that can be implemented in a method used in the production of the object, in particular a process-stable, realizable extreme value for the parameter.

19. A test device according to claim 18, wherein the limit parameter value is an extreme value for the parameter that can be produced by means of the generative layer construction device, in particular an extreme value for the parameter which can be produced by the generative layer construction device in a process-stable manner.

20. A test apparatus according to claim 18 or 19, wherein when the object is manufactured by the generative layer building apparatus in a first production method, the marginal parameter value is an extreme value producible by a second manufacturing method other than the first production method is the parameter and / or a processable extreme value for the parameter in a process downstream of the first production process.

21. The test apparatus of claim 18, further comprising an input device for manipulating the computer-based model by a user.

22. Testing device according to one of claims 18 to 21, wherein the computer-based model of an object to be produced by means of the generative layer building apparatus (3) and the limit values are stored in one and the same storage device.

23. Generative Schichtbauvorrichtung for producing at least one three-dimensional object by means of layered solidification of a pul-shaped or liquid Aufbaumateri- as with

a construction substrate (2) for supporting the at least one object to be produced (3), an application device (12) for applying a layer of the powdered or liquid building material to the construction substrate (2) or a previously applied and selectively consolidated layer of the construction material,

a selective solidifying device (6, 8, 9) capable of acting on all the points in the applied layer corresponding to a cross section of the at least one object to be manufactured (3), such that the building material is at these points connects to a solid, and

a control unit (10) which controls the application device (12) and the selective solidification device (6, 8, 9) such that the object is produced by successive selective solidification of layers of the construction material,

wherein the generative layer construction device comprises a test device according to one of claims 18 to 22 and / or is connected by signal technology with such a test device.

24. A computer program comprising a sequence of instructions by which a method according to any one of claims 1 to 17 is performed when the computer program is executed by means of a data processor.