DE102022202664A1 - Method and device for targeted particle arrangement in resin-based additive manufacturing - Google Patents

Abstract

The invention relates to a method for targeted particle arrangement in resin-based additive manufacturing, wherein particles (10) are mixed with a resin system (12) to form a particle mixture (14), wherein a component (16) is produced by applying the particle mixture (14) in layers , wherein an exposure process is provided between two application processes of the particle mixture (14), in which the applied layer is hardened by a light source (18).In a method for resin-based additive manufacturing, in which a targeted particle orientation in the resin system (12) is made possible, It is provided that an arrangement unit (20) is provided, through which a force is provided before and/or during the exposure process, which can be selectively adjusted in relation to the area, the force being provided by means of an electric and/or a magnetic field and the particles (10) can be arranged according to the field strength of the electric and/or magnetic field.

Description

The invention relates to a method for targeted particle arrangement in a resin-based additive manufacturing, wherein particles are mixed with a resin system to form a particle mixture, a component being produced by applying the particle mixture in layers, an exposure process being provided between two application processes of the particle mixture, in which the applied layer is cured by a light source.

In addition, the invention relates to a device for producing a component by means of resin-based additive manufacturing, with at least one printing device for applying a particle mixture of a resin system and particles in layers, with at least one light source for curing a layer of the particle mixture.

Additive manufacturing processes for producing components, in particular made of plastic, are known in the prior art in a variety of configurations. Currently, in resin-based additive manufacturing, resin systems are selectively cured layer by layer using an exposure source, resulting in a component. Particles in the resin system can influence the mechanical or optical properties. The integration of particles into the resin system, known from the prior art, is designed in such a way that the particles are present homogeneously in the resin system and therefore also homogeneously in the cured component.

The DE 10 2014 111 559 A1 shows, for example, a method for producing a sequence of layers. A paste is provided that contains a crosslinkable material. The paste is applied in a first layer, with a subsequently applied second layer comprising a photoreactive compound. The photoreactive compound layer is applied in a predetermined two-dimensional distribution to create reactive areas of the first layer and the second layer. The crosslinkable material is crosslinked by activating the photoreactive compound, with crosslinking of the crosslinkable material occurring corresponding to the reactive areas. In addition, a filling material can be provided, which has, for example, glass, ceramics, metal, metal alloys, etc.

The DE 10 2014 220 083 A1 discloses a method for producing a three-dimensional component layer by layer from a strand of material. For this purpose, particles and binder material are provided, which are mixed together. The particle mixture is applied layer by layer in the form of a three-dimensional component. The component is then hardened. The particles can be different materials.

A disadvantage of the aforementioned prior art is that only homogeneous distributions in the particle mixture are possible. In order to specifically influence the properties of the components, inhomogeneous, selective distributions of particles in the resin system would also be useful with regard to the setting of targeted mechanical or optical properties.

The invention is based on the object of specifying a method and a device for resin-based additive manufacturing, in which targeted particle orientation in the resin system is made possible.

In the present invention, this object is initially achieved by the features of the characterizing part of patent claim 1 in that an arrangement unit is provided, through which a force is provided before and / or during the exposure process, which can be selectively adjusted in relation to the area, the force being used by means of an electric and/or a magnetic field is provided and the particles are arranged according to the field strength of the electric and/or the magnetic field, in particular are arranged selectively within the layer plane.

In the present case, area-related selective adjustment is understood to mean that the force provided is changed selectively depending on the location with respect to the area (plane) of the layer of the particle mixture, so that the force at one location or an XY coordinate is greater than at another location or at one can be another XY coordinate. This also includes that the force can be zero at one location or at one XY coordinate and a force greater than zero is provided at another location or at another XY coordinate. Preferably, the force can be selectively adjusted over the entire layer plane, i.e. over the entire surface.

In this way, the mechanical and optical properties of a component can be optimally adapted to the respective requirements of the component. In addition, the targeted arrangement of, for example, electrically conductive particles within the component creates a conductive component or a conduction option within the component.

The particles can be metallic, ceramic or polymeric materials and/or electrically conductive and/or light-conducting materials. Conceivable are, for example, graphite, metallic materials such as iron, copper, nickel, magnesium and glass. The particles do not adversely affect the properties of the starting material or the manufacturing process. The particles can either always have the same particle size or a particle size distribution. Conceivable particle sizes are in the range of 5 - 1000 µm. Particle sizes in the range of 50 - 500 µm are preferred, in particular particle sizes in the range of 51 - 250 µm. As the particle size decreases, the level of detail increases. The particles are first mixed into the resin system depending on the amount required. The mixing is done manually or mechanically using a mixing process. The proportion of particles in the resin system depends on the respective requirements of the component. Furthermore, the particles must not influence the layer-by-layer illumination of the resin. The invention can be used for any resin systems in resin-based additive manufacturing.

In order to arrange the particles within the resin system and the later component in a targeted manner, an arrangement unit is required which can be activated before and during each lighting process and remains activated at least until the respective layer has hardened. The arrangement unit provides a force which can be selectively adjusted in relation to the area (in particular over the entire area). A surface-related variable magnetic or electric field is conceivable, which arranges the particles within the layer plane according to the magnetic or electric field strength. The effective field strength transforms the particles from a disordered state into an ordered state. Any arrangement of the particles within the resin system of each layer is conceivable. The individual particles can be in contact or present individually. The arrangement unit is selected according to the particular particles used.

The method according to the invention improves material efficiency, multi-material printing and leads to an adaptation of the mechanical properties to the respective requirements of the component. Furthermore, the use of cost-intensive materials is minimized because these materials can be arranged in a targeted manner. In addition, an increase in the potential of powder-based additive manufacturing can be achieved. Furthermore, cost savings are achieved by reusing waste products as particles.

Further preferred embodiments of the invention result from the remaining features mentioned in the subclaims.

In a first embodiment of the method according to the invention it is provided that the electric and/or magnetic field remains permanently switched on. Consequently, the arrangement unit can remain permanently switched on throughout the entire printing process, so that forced particle orientation occurs permanently. This can ensure that the desired particle orientation is achieved.

Alternatively, in a further embodiment of the method according to the invention, it can be provided that the electric and/or magnetic field is switched off when a layer has hardened. Since the method provides for a layer-by-layer structure of a three-dimensional component in which each layer is cured individually, in order to save energy, it may make sense to switch off the arrangement unit when a layer has hardened and the particles are fixed in the desired orientation .

In a particularly preferred embodiment of the method according to the invention, it is provided that the particles are electrically conductive and that the particles are arranged by the arrangement unit in such a way that at least one electrical conductor track is built up in at least one layer. This enables the targeted, individual and optimal design of conductor tracks within additively manufactured components. For an electrically conductive conductor track, the particles must be in contact with each other. It is conceivable that not only two-dimensional conductor tracks are generated within a layer, but also three-dimensional branches that can be realized across layers by particles that are connected to one another.

Additionally or alternatively, in a further embodiment of the invention it can be provided that the particles are light-conducting and that the particles are arranged by the arrangement unit in such a way that at least one light-conducting conductor track is built up in at least one layer. Analogous to electrically conductive conductor tracks, light-conducting particles must also be in contact with one another in order to generate light-conducting conductor tracks. It is also conceivable that not only two-dimensional conductor tracks are generated within a layer, but also three-dimensional branches that can be realized across layers by particles that are connected to one another. The light-conducting conductor tracks can also achieve design effects. For example, logos or geometric shapes created by light-conducting conductor tracks within the layered component are conceivable. Furthermore, the coloring of the component can be achieved using a targeted setting set of colored particles can be significantly influenced.

Furthermore, in a further embodiment of the method according to the invention, it can additionally or alternatively be provided that the particles are arranged by the arrangement unit in such a way that a reinforcement of the component to be created is produced in at least one layer. Local particle reinforcements within a component are therefore conceivable in order to increase the mechanical properties of the component. The density of the component can also be adjusted locally or over the entire surface.

In a further embodiment of the invention it is provided that a DLP method or an SLA method is used. Both processes represent a resin-based option for creating three-dimensional components, in which a light source is used to harden the component layer by layer. The SLA process, known as stereolithography, uses a laser as a light source, whereby the laser scans a resin shell or resin bath and solidifies the material layer by layer. By means of a mirror device located between the resin and the laser, the light can be reflected towards the resin.

In the DLP process, the so-called digital light processing, a projector is used as a light source. In this way, the entire resin bowl or resin bath is illuminated.

The aforementioned object is also achieved by a device for producing a component using resin-based additive manufacturing, with at least one printing device for applying a particle mixture of a resin system and particles in layers, with at least one light source for curing a layer of the particle mixture. Furthermore, an arrangement unit is provided, wherein an electric and/or magnetic field can be generated by the arrangement unit, which can act on the particles in a particle mixture in such a way that the particles can be aligned according to the field strength of the electric and/or magnetic field.

In a first embodiment of the device according to the invention it is provided that a method according to the invention can be carried out by the device. The above statements regarding the method according to the invention also apply accordingly to the device according to the invention.

In a further embodiment of the device according to the invention it is provided that the arrangement unit is replaceable. The arrangement unit can therefore be present separately. The arrangement unit can be replaced depending on the type of particles used. Depending on the resin-based additive manufacturing process, the arrangement unit can be arranged above or below a resin bath of the device.

The various embodiments of the invention mentioned in this application can be advantageously combined with one another, unless stated otherwise in individual cases.

• 1 eine schematische Darstellung eines Ausführungsbeispiel eines erfindungsgemäßen Verfahrens bei Verwendung eines DLP-Verfahrens,
• 2 eine schematische Darstellung eines weiteren Ausführungsbeispiels eines erfindungsgemäßen Verfahrens bei Verwendung eines SLA-Verfahrens und
• 3 Beispiele der gezielten Anordnung von Partikeln in einer Schicht eines dreidimensionalen Bauteils.

The invention is explained below in exemplary embodiments using the associated drawings. Show it:

• 1 a schematic representation of an exemplary embodiment of a method according to the invention when using a DLP method,
• 2 a schematic representation of a further exemplary embodiment of a method according to the invention when using an SLA method and
• 3 Examples of the targeted arrangement of particles in a layer of a three-dimensional component.

1 shows schematically the implementation of a method for targeted particle arrangement in additive manufacturing. Particles 10 are mixed with a resin system 12, so that a particle mixture 14 is created. A three-dimensional component 16 is produced by applying the particle mixture 14 in layers. Each applied layer is first cured using a light source 18 before the next layer is applied. In addition, an arrangement unit 20 is provided, through which a force is provided before and/or during the exposure process, which can be selectively adjusted over the entire area, the force being provided by means of an electric and/or a magnetic field and the particles corresponding to the field strength of the electric and/or the magnetic field can be arranged.

In 1 A total of a device 22 is shown, with which a method for targeted particle arrangement can be carried out in additive manufacturing. The particle mixture 14 can be applied in layers using a printing device 24. For this purpose, the particle mixture 14 is first arranged in a resin bath 26. The mixing process of the particle mixture 14 can be carried out mechanically in an upstream step.

Depending on the desired result, the particles 10 can be metallic, ceramic or polymeric materials as well as electrically conductive or light-conducting materials. In the present exemplary embodiment, the particles 10 are present in a size distribution between 50 - 500 μm. This ensures a sufficient level of detail for the respective application.

The particles 10 are first mixed into the resin system 12 depending on the required amount. In order to specifically arrange the particles 10 within the resin system 12 and the later component 16, the arrangement unit 20 is used. The arrangement unit 20 remains activated until the respective layer has hardened. The arrangement unit 20 provides a force through a magnetic field through which the particles 10 can be oriented in a targeted manner. The magnetic field acts selectively over the entire area in the area in which the component 16 is to be created.

At the in 1 As can be seen, the component 16 is manufactured using the DLP process. In the DLP process, the so-called digital light processing, a projector is used as a light source 18 to harden the respective layers.

2 shows a further method variant or a device 22 for producing a component 16 through a targeted particle arrangement in resin-based additive manufacturing. At the in 2 The procedure that can be seen is an SLA procedure. The SLA process, the so-called stereolithography, uses a laser as a light source 18. By means of a mirror device 28, which is located between the resin system 12 and the laser, the light can be reflected in the direction of the resin system, with the laser scanning a resin bath 26 and the material solidifies in layers.

3 shows various application examples that are possible using the method according to the invention or the device 22. In 3 Different layers with different particle arrangements are shown in a top view. Depending on the choice of the nature of the particles 10 and the corresponding arrangement of the particles 10 in the particle mixture 14, the properties of the component 16 to be created can be specifically adapted.

The particles 10 can, for example, be electrically conductive. The particles 10 can then be arranged by the arrangement unit 20 in such a way that at least one electrical conductor track is built up in at least one layer. This enables the targeted, individual and optimal design of conductor tracks within the additively manufactured component 16. For an electrically conductive conductor track, the particles 10 are in contact with one another (compare example on the right). Not only two-dimensional conductor tracks can be generated within a layer, but also three-dimensional branches, which can be realized across layers by particles 10 that are connected to one another (not shown here).

In addition, the particles 10 can be designed to be light-conducting. The particles can then also be arranged by the arrangement unit 20 in such a way that at least one light-conducting conductor track is built up in at least one layer. Analogous to electrically conductive conductor tracks, light-conducting particles 10 must also be in contact with one another in order to generate light-conducting conductor tracks. The light-conducting conductor tracks can also be used to achieve design effects, as indicated in the second example from the right, in which an outer shell is formed, which, given the appropriate color of the particles 10, significantly shapes the external appearance of the component, without the particles 10 being completely inside the Component 16 must be present. In this way, material for the more expensive particles 10 can be saved.

In addition, the particles 10 can be used for stabilization. In the second example from the left it can be seen that the particles 10 are arranged by the arrangement unit 20 in such a way that a reinforcement of the component 16 to be created is created in the edge regions of the layer. In this way, the mechanical properties of the component 16 can be specifically adjusted. Furthermore, the density of the component 16 can be specifically adjusted (compare first example from the left) by introducing the desired number of particles 10, whose density is different from the density of the resin system 12, into the particle mixture 14.

Reference symbol list

10

particles

12

Resin system

14

Particle mixture

16

Component

18

light source

20

Arrangement unit

22

contraption

24

Printing device

26

Resin bath

28

Mirror device

QUOTES INCLUDED IN THE DESCRIPTION

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

Cited patent literature

• DE 102014111559 A1 [0004]
• DE 102014220083 A1 [0005]

Claims (10)

Method for targeted particle arrangement in resin-based additive manufacturing, wherein particles (10) are mixed with a resin system (12) to form a particle mixture (14), wherein a component (16) is produced by applying the particle mixture (14) in layers, with between two During the application processes of the particle mixture (14), an exposure process is provided, in which the applied layer is hardened by a light source (18), characterized in that an arrangement unit (20) is provided, through which a force is provided before and / or during the exposure process , which can be selectively adjusted in relation to the area, the force being provided by means of an electric and/or a magnetic field and the particles (10) being arranged according to the field strength of the electric and/or the magnetic field. Procedure according to Claim 1 , characterized in that the electric and/or magnetic field remains permanently switched on. Procedure according to Claim 1 , characterized in that the electric and/or magnetic field is switched off when a layer has hardened. Procedure according to one of the Claims 1 until 3 , characterized in that the particles (10) are electrically conductive and that the particles (10) are arranged by the arrangement unit (20) in such a way that at least one electrical conductor track is built up in at least one layer. Procedure according to one of the Claims 1 until 4 , characterized in that the particles (10) are light-conducting and that the particles (10) are arranged by the arrangement unit (20) in such a way that at least one light-conducting conductor track is built up in at least one layer. Procedure according to one of the Claims 1 until 5 , characterized in that the particles (10) are arranged by the arrangement unit (20) in such a way that a reinforcement of the component (16) to be created is produced in at least one layer. Procedure according to one of the Claims 1 until 6 , characterized in that a DLP process or an SLA process is used. Device (22) for producing a component (16) by means of resin-based additive manufacturing, with at least one printing device (24) for applying a particle mixture (14) made of a resin system (12) and particles (10) in layers, with at least one light source (18 ) for curing a layer of the particle mixture (14), characterized in that an arrangement unit (20) is provided which is designed to generate an electric and / or magnetic field, the electric and / or magnetic field being applied to the particles (10 ) in the particle mixture (14) can act in such a way that the particles (10) can be aligned according to the field strength of the electric and / or magnetic field. Device (22) after Claim 8 , characterized in that the device (22) is designed according to one of the methods Claims 1 until 7 to carry out. Device (22) after Claim 8 or 9 , characterized in that the arrangement unit (20) is replaceable.

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