DE102018001510A1 - Device and method for producing 3D molded parts by means of improved Partikelmaterialdosiereinheit - Google Patents

Abstract

The invention relates to a device for producing 3D molded parts by means of particulate material metering unit.

Description

The invention relates to an apparatus and a method for producing three-dimensional models by means of layer construction technique.

In the European patent specification EP 0 431 924 B1 A method of manufacturing three-dimensional objects from computer data will be described. In this case, a particulate material is applied in a thin layer on a platform and this selectively printed by means of a print head with a binder material. The particle area printed with the binder sticks and solidifies under the influence of the binder and optionally an additional hardener. Subsequently, the platform is lowered by one layer thickness into a structural cylinder and provided with a new layer of particulate material, which is also printed as described above. These steps are repeated until a certain desired height of the object is reached. The printed and solidified areas create a three-dimensional object.

This object made of solidified particulate material is embedded after its completion in loose particulate material and is subsequently freed from it. This is done for example by means of a nipple. The desired objects then remain, which are then removed from the residual powder, e.g. be freed by brushing.

A problem with known methods of 3D printing in which particulate materials are applied is a lump-free material application. The particulate material is placed in a coater (recoater) and applied in layers to the building level. It often happens that the particle material adheres to larger particles and loses its fluidity or is applied as a particle aggregate on the construction level and thus leads to inaccuracies in the produced 3D-Fromteil or this is completely useless for quality reasons.

Another problem is that the outlet of the coater is partially or / and temporarily closed and then at least for a short time no particulate material passes through the coater opening on the building level. This can lead to cavities in the produced 3D molded part as well as inaccuracies in the form precision or / and to disadvantages with regard to the strength or stability of the 3D molded part.

It was therefore an object of the present invention to provide constructive means which allow an improved 3D printing process or at least to improve or avoid the disadvantages of the prior art.

In particular, it was an object of the present invention to provide an apparatus and a method in which it is structurally achieved that particle aggregate formation is reduced or substantially prevented.

Brief summary of the invention

In one aspect, the invention relates to a device which is suitable for carrying out a method according to the invention for producing 3D molded parts, the device comprising or comprising at least one application means, such as a dosing body, optionally one or more dosing carrier carriers and optionally one or more leveling agents, at least one filter means, such as a sieve body.

In a further aspect, the invention relates to a method for producing 3D molded parts, wherein particulate building material in a defined layer is applied by coater to a construction field, selectively applying one or more liquids or particulate binder, using a coater that is an agent or a combination of agents that reduce or substantially prevent particle aggregation.

In a further aspect, the invention relates to an apparatus for producing molded parts comprising a device as described herein.

In a further aspect, the invention relates to a 3D molded part manufactured by means of a device or a method as described herein.

list of figures

• 1 1 shows an aspect of an embodiment according to the invention, wherein a powder reservoir wall (FIG. 4 . 4 ' ) a powder material reservoir ( 17 ) forms and also a screen body ( 1 ), Dosing body ( 2 ), Dosing carrier ( 3 ) are shown. The direction of movement ( 5 ) of the dosing is indicated by an arrow and this can be controlled in both directions of rotation. The powder reservoir wall ( 4 . 4 ' ) can form a counter-wall ( 21 . 21 ' ). The unit of dosing body ( 2 ) and dosing carrier ( 3 . 3 ' ) can also be referred to as a metering roller.
• 2 shows an aspect of an embodiment according to the invention, wherein the dosing body ( 2 ) between the powder reservoir wall ( 4 . 4 ' ) is designed as a horizontally movable doctor blade in the direction of arrow ( 5 ) over the sieve body ( 1 ) is moved to the particulate matter delivery.
• 3 shows an aspect of an embodiment according to the invention ( 6 ), whereby among the Powder reservoir walls ( 4 . 4 ' ) two drive means ( 24 . 24 ' ) are arranged. The dosing bodies ( 2 ) move in the direction of the arrow ( 5 ) and are connected to a Dosierkörperband ( 16 ).
• 4 1 shows an aspect of an embodiment according to the invention which is used as a coater ( 7 ), wherein a particulate material dosing unit ( 6 ) above (particle material flow direction) of a leveling unit ( 8th ) is attached. The particulate matter is removed from the interior ( 17 ) of the particulate material dosing unit ( 6 ) by means of dosing ( 2 ) in the leveling unit interior ( 20 ). The distance of the dosing bodies ( 2 ) of each other, their dimensions and the through this and the surface of the Dosierkörperträgers ( 3 ) as well as the sieve body ( 1 ) enclosed volume defines the particle material volume ( 19 ). The particulate material is fed via the dosing gap ( 18 ) of the leveling unit ( 8th ) applied to the building level and leveled.
• 5 1 shows an aspect of an embodiment according to the invention, wherein a variation of a leveling unit (FIG. 8th' ) together with a particulate metering unit ( 6 ) is shown. Leveling unit ( 8th' ) is used together with the particulate material dosing unit ( 6 ) in the direction of the arrow ( 9 ) while the particulate matter is applied to the building level. The leveling unit ( 8th' ) smoothes the deposited particulate material smooth and flat during its passage, whereby the layer thickness can be adjusted by suitable means.
• 6 shows an aspect of an embodiment according to the invention, wherein different forms of the dosing ( 2 ) when ( 10 ) 11 ), (12) and (13) are shown. The dosing bodies ( 2 ' . 2 ' ) are each on a Dosierkörperträger which as Dosierkörperband ( 16 ) is executed, attached to, connected to or form a unit with this.
• 7 shows a specific embodiment of the invention, wherein the filter means ( 1 ) rotates (in the direction of the arrow ( 22 ), possible in both directions) and the dosing body ( 2 ) is rigid, preferably not movable, is formed. The internal volume of the filter medium ( 1 ) provides the particulate matter reservoir ( 23 ). The application volume is determined by the rotational speed and the mesh size of the filter medium.

Detailed description of the invention

According to the invention an object of the application is achieved by a Partikelmaterialdosiereinheit, which is suitable for the layered structure of moldings, comprising a particulate material reservoir, at least one applicator, optionally one or more Dosierkörperträger, optionally one or more leveling agents, and at least one filter means (strainer) ,

According to the invention, an object underlying the application is achieved by a system for producing molded parts, comprising a particle material metering unit as described herein.

According to the invention, an object underlying the application is achieved by a method which uses a particle material metering unit as described herein.

In the following, some terms of the invention are first explained in more detail.

"3D molded part", "shaped article" or "component" in the sense of the invention are all three-dimensional objects produced by means of the method according to the invention and / or the device according to the invention, which have a dimensional stability.

"Construction space" is the geometric location where the particulate material bed grows during the construction process by repeated coating with particulate material or through which the bed passes through continuous principles. In general, the space is limited by a floor, the building platform, by walls and an open deck, the building level. In continuous principles, there is usually a conveyor belt and bounding sidewalls. The installation space can also be configured by a so-called job box, which represents a device which can be moved in and out of the device and allows batch production, a job box being extended after the process has ended and a new job box being able to be moved into the device immediately, so that the Production volume and thus the device performance is increased.

As "particulate materials" or "particulate building materials" or "building materials", all materials known for powder-based 3D printing may be used, in particular silicates (e.g., sands), carbides, concrete, polymers, ceramics, and metals. The particulate material is preferably a dry free-flowing powder, but a cohesive cut-resistant powder or a particle-laden liquid may also be used. In this document particulate material and powder are used synonymously.

The "particulate material application" is the process by which a defined layer of powder is produced. This can be done either on the build platform or on an inclined plane relative to a conveyor belt with continuous principles. The particle material application is also referred to below as "coating" or "recoating".

For the purposes of the invention, "selective liquid application" can take place after each particle material application or, depending on the requirements of the shaped article and for optimizing the production of shaped articles, also irregularly, for example several times based on a particle material application. In this case, a sectional image is printed by the desired body.

As a "device" for carrying out the method according to the invention, any known 3D printing device may be used, which includes the required components. Typical components include recoaters, construction field, means for moving the construction field or coater / printhead and / or other components in continuous processes, metering devices and heat and radiation means, and other components known to those skilled in the art for powder-based 3D printing processes and devices can be used with selective solidification and therefore are not detailed here.

The building material is always applied in a "defined layer" or "layer thickness", which is adjusted individually depending on the building material and process conditions. It is for example 0.05 to 0.5 mm, preferably 0.1 to 0.3 mm.

A "particulate material dosing unit" in the sense of the invention comprises suitable means for achieving a uniform particulate material for application from the coater. It is useful for this purpose e.g. one or more dosing bodies, which may be made either with a filter medium, also in particular as a sieve body or sieve, e.g. is combined as a filter cloth or perforated plate or e.g. one or more dosing bodies, combined with one or more Dosierkörperträgern, which may also be combined with a filter medium. Suitable alone or in the latter combination is also the passing of dosing on a surface (which may also be referred to as mating surface) to break up possible particle aggregates and apply a uniform particulate material with uniform flowability on the construction level. It is advantageous to attach at least two dosing to a Dosierkörperträger at a defined distance, so that on the one hand a volume (three-dimensional gap) forms with the surface of Dosierkörperträgers and the mating surface between the dosing and on the other hand, preferably shear forces can be generated, the breaking up of particle aggregates permitting substantially uniform and flowable particulate material to be applied to the building level. It can also be followed by a filter means of this arrangement. Preferably, the filter means improves the disruption and homogenization of the particulate material. The "particulate material dosing unit" may be followed by a leveling unit, wherein the leveling unit is a roller or blade and / or a blade is connected downstream of the particulate material reservoir / coater.

A "coating agent" within the meaning of the invention is a means that facilitates the particle material application or / and supports a uniform application and distribution of the particulate material. The "coating agent" may be a dosing body or a squeegee or a conductive agent or dosage form, preferably wherein the conductive agent is a baffle, preferably wherein the squeegee or the conductive agent consists of or comprises a plastic or a metal.

A "leveling unit" within the meaning of the invention may be one or more blades or one or more rollers or one or more wipers or other suitable means.

A "filter means" in the context of the invention is a screen body in the form of z. As a grid or perforated plate or filter fabric through which the particulate material is transported before application to the building level.

A "dosing" may have different characteristics in the context of the invention and be adapted to other device parts advantageous. A "dosing body" can be round, oval, angular, with a round or pointed tip and be designed either individually or in several coupled or independent parts. A "dosing" can be moved directly or via one or more Dosierkörperträger.

A "Dosierkörperträger" within the meaning of the invention may serve to move or to move one or more dosing. The dosing bodies can be mounted directly on the "Dosierkörperträger" or controlled by other means through the "Dosierkörperträger" and / or moved. The coupling of "Dosierkörperträger" and Dosierkörpern can be done by suitable means, for example by gluing or welding (see also 3 . 4 . 6 ).

A "powder reservoir" according to the invention is constructed or / and limited by one or more powder reservoir walls. The "powder reservoir" can also be formed by the internal volume of the filter medium (see, eg 7 , Reference number ( 23 )). In this "powder reservoir", according to the invention, one or more dosing bodies can be present alone or together with one or more dosing carrier carriers and one or more filter media.

A "direction of movement of the dosing" in the context of the invention refers to the movement, by means of which the particulate material is conveyed to the building level and possibly existing particle aggregates are broken and the particulate material is again substantially uniform flowable.

A "particulate metering unit" within the meaning of the invention may be designed as a coater (recoater), for. B. in combination with a leveling unit, or a coater (Recoater) fill when it is upstream.

The aspects of the invention are described below.

The invention relates to a device, a system and a method.

With the help of the device, system and method of the invention could surprisingly very advantageous process results can be achieved and high quality components are obtained.

It has been possible and has been achieved particularly advantageously that particle material aggregates are broken up and the applied particulate material can be applied substantially uniformly and flowable to the building level.

With the device, system and method according to the invention, the problems or disadvantages of the prior art described above are at least reduced or substantially or completely avoided.

The invention relates in one aspect to a particulate metering unit which is suitable for the layered construction of moldings comprising a particulate material reservoir, at least one application agent, optionally one or more Dosierkörperträger, optionally one or more leveling agents, and at least one filter means (screen body).

In one aspect, the particulate material metering unit is characterized by at least one metering body and one or more filter media (screen body). This makes it possible advantageously to obtain homogeneous particulate material without agglomerates and applied to the construction level.

In one aspect, the particulate material dosing unit is characterized by at least one dosing body and optionally one or more Dosierkörperträger and optionally at least one counter wall. With this combination, particle material agglomerates can advantageously be broken up and essentially homogeneous particle material applied and high-quality 3D molded parts obtained. Shearing forces between dosing carrier body, dosing body and counterwall help break up particulate agglomerates and homogenize the particulate matter.

Further embodiments of the device according to the invention are designed as follows.

In the case of a particulate material metering unit according to the invention, the particulate material reservoir can be designed so that the filter medium or filters are mounted on the underside thereof in the material flow direction. The particulate material metering unit according to the invention can have a coating agent which is designed as a metering body or a doctor blade or a conducting agent. The device may also comprise at least one dosing body and further a conducting agent, e.g. have a baffle, or a squeegee. These components may consist of or comprise a plastic or a metal.

In one aspect, the particulate material dosing unit may comprise one or two dosing bodies or dosing carrier carriers, preferably in combination as dosing roller, the dosing body or dosing carrier carriers being e.g. are configured as a circular shape, elliptical shape, prism shape and / or as a brush trim, or represent a metering roller.

Furthermore, the particulate material metering unit according to the invention may have a plurality of dosing bodies, preferably 4 to 20 dosing bodies, in combination with a dosing carrier as dosing roller or dosing bodies mounted on a dosing carrier body, the dosing carrier being moved by the drive means or the drive means, preferably wherein the dosing carrier carriers are configured as a roller or straps.

A particle material metering unit according to the invention can have a volume between two metering bodies (and the corresponding boundaries by metering body carrier and counterwall, or the internal volume of the filter means) of 1 to 3000 cm ³ , preferably 15 to 1000 cm ³ .

A particulate material metering unit according to the invention may comprise a leveling agent, wherein the leveling agent or levels consist of or comprise a roller or / and a blade.

A particle material metering unit according to the invention may comprise a filter medium, the filter medium being upstream or downstream of the metering body or bodies, preferably wherein the filter medium is connected downstream of the metering roll (s) with respect to the material flow direction. The filter medium can also form an interior in which the is to be applied particulate material or is introduced into this. This can be done continuously or step by step.

In a particle material metering unit according to the invention, the filter medium or filters may consist of or comprise a mesh, preferably a wire mesh, a woven fabric or / and a perforated sheet, and preferably a passage width (mesh size) for the particulate material, e.g. a mesh size of 10 to 2500 microns, preferably 50-500 microns and the perforated plate preferably have a pitch of 1-10, preferably 1-8 mm.

In a further aspect, the invention relates to a plant for producing moldings comprising a particulate material metering unit as described herein.

The invention relates in one aspect to a method for producing molded parts, comprising the steps of applying particulate material with a particulate dosing unit as described herein, wherein the amount of the particulate material by means of relative speed of the dosing or to the filter medium and / or by means of Dosierkörperanordnung and / or the Dosierkörperausführung is controlled and a construction field is run over with the Partikelmaterialdosiereinheit and when passing a particle material layer is applied or the construction field is moved, solidifying selected areas by suitable means, repeating these steps until the desired moldings or are constructed and optionally performing another Processing steps on the molded parts thus produced.

A constant amount of particulate material can be applied by means of the particulate material dosing unit whose volume can be determined by the design selection of the dosing bodies.

By means of the method according to the invention, a substantially agglomerate-free particulate material can be applied by means of the particulate material dosing unit.

The method of the invention can use various material systems, e.g. a material system comprising a powdery material with a high fines content, which preferably has an average particle size of <250 μm.

The invention also relates to a method for producing molded parts, comprising the steps of applying particulate material with a particulate material dosing unit as described herein or filling a coater (recoater) with a particulate material dosing unit as described herein.

A further aspect of the invention is a 3D molded part which has been produced by means of a device or method according to the invention.

example

The invention is illustrated below by way of example, which is not intended to be limiting.

In one embodiment, the invention is considered to be a coater fill with the particulate material metering unit as in FIG 4 shown. A Radialdosiereinheit according to the invention is also in 1 to be seen separately. The powder material feed takes place in such a way that six (6) circular dosing bodies are mounted on a round dosing carrier. In this case, a filter medium was used whose Siebmaschenweite of 250 .mu.m was selected. The dosage is carried out in a controlled manner, for example, wherein the speed of the metering roller is set to 150 to 200 U / min. A certain speed can be at 180 rpm.

It can e.g. ceramic powder (zirconium oxide D 45μm) are processed, but also other powder materials with corresponding grain sizes.

LIST OF REFERENCE NUMBERS

No.

designation

1

filter means

2, 2 ', 2' '

metering

3

Dosierkörperträger

4, 4 '

Particle / powder reservoir wall

5

Direction of movement dosing body

6

Particulate material metering

7

Coater (recoater)

8, 8 '

leveling

9

Direction of movement of particulate material dosing unit

10

circularity

11

elliptical shape

12

brush border

13

prism shape

14

nubbed belts

15

brush belts

16

Dosierkörperband

17

Particulate material reservoir (interior of ( 6 ))

18

metering

19

Particulate matter volume

20

Leveling interior

21, 21 '

against wall

22

Direction of rotation filter media

23

Particle material reservoir

24, 24 '

drive means

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

• EP 0431924 B1 [0002]

Claims (10)

Particulate material dosing unit suitable for the layered construction of moldings, comprising a particulate material reservoir, at least one application agent, one or more leveling agents, and at least one filter medium. Particle material metering unit according to Claim 1 , wherein the particulate material reservoir is designed so that the filter or the filter means are mounted on the underside in the direction of material flow or act as a particulate material reservoir itself or / and wherein the application means is at least one dosing or at least one dosing on a Dosierkörperträger or is a conductive agent, preferably wherein Conductor is a baffle, preferably the conductive means consists of or comprises a plastic or a metal. Particulate material dosing unit according to one of Claims 1 to 2 wherein the Partikelmaterialdosiereinheit has one or two metering or Dosierkörperträger, preferably in combination as metering, wherein the or the metering or Dosierkörperträger are configured as a circular shape, ellipse shape, prism shape and / or brushing. Particulate material dosing unit according to one of Claims 1 to 3 , wherein a plurality of dosing, preferably 4 to 20 dosing, are designed in combination with a Dosierkörperträger dosing, or are mounted on a Dosierkörperträger dosing, wherein the Dosierkörperträger is moved by the one or more drive means, preferably wherein the Dosierkörperträger are configured as a roller or belt , Particulate material dosing unit according to one of Claims 1 to 4 wherein the volume between two dosing bodies is from 1 to 3000 cm ³ , preferably from 15 to 1000 cm ³ , and / or wherein the leveling agent or agents consist of or comprise a roller and / or a blade or / and wherein the filter medium is the application agent (s) is upstream or downstream, preferably wherein the filter means of the metering rollers or is connected downstream with respect to the material flow direction. Particulate material dosing unit according to one of Claims 1 to 5 , wherein the one or more filter means consist of or comprise a braid, preferably a wire mesh, a fabric and / or a perforated plate and preferably a passage width (mesh size) for the particulate material, for example a mesh size of 10 to 2500 .mu.m, preferably 50-500 .mu.m and the perforated plate preferably has a pitch of 1-10, preferably 1-8 mm. Plant for the production of moldings comprising a particulate material dosing unit according to one of Claims 1 to 6 , A method of manufacturing molded articles, comprising the steps of: applying particulate material to a particulate material dosing unit according to any one of Claims 1 to 6 , wherein the amount of the particulate material is controlled by means of relative speed of the dosing or to the filter medium and / or by Dosierkörperanordnung and / or Dosierkörperausführung and a construction field is run over with the Partikelmaterialdosiereinheit and when passing a particle material layer is applied or the construction field is moved, solidification of selected areas with suitable means or the construction field is moved, repeating these steps until the desired moldings or parts are constructed and optionally carrying out further processing steps on the moldings thus produced. A method of producing molded articles, comprising the steps of: applying particulate material to a particulate material dosing unit according to any one of Claims 1 to 6 or filling a coater (recoater) with a particulate material dosing unit according to any one of Claims 1 to 8th , Method according to Claim 9 in which a constant amount of particulate material is applied by means of the particulate material dosing unit and / or in which a substantially agglomerate-free particulate material is applied by means of the particulate material dosing unit and / or a material system, eg a high-fines powder material, which preferably has an average particle size of < 250μm has.

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