WO2014139491A1

WO2014139491A1 - Generative method for producing a component having at least one channel by 3d printing by means of a sand and a binding agent

Info

Publication number: WO2014139491A1
Application number: PCT/DE2014/000041
Authority: WO
Inventors: Asko FROMM
Original assignee: Universität Kassel
Priority date: 2013-03-11
Filing date: 2014-02-01
Publication date: 2014-09-18
Also published as: DE102013005891A1

Abstract

The invention relates to a generative method for producing a component having at least one cavity, in particular by 3D printing by means of a sand and a binding agent, wherein the component produced by way of the generative method is soaked in a liquid, curable composition to increase strength.

Description

GENERATIVE METHOD FOR PRODUCING A COMPONENT WITH AT LEAST ONE CHANNEL, BY SD PRINTING TECHNOLOGY WITH ONE SAND AND ON A BINDER

The invention relates to a generative method for producing a component having at least one channel by 3D printing technology with a sand and a binder, wherein the at least one channel projects at at least one end up to the edge of the component.

Not only the 3D printing technology, but also the so-called "selective" process belongs to the generative process for the production of components

Laser sintering "and" Fused disposed modeling ". All three methods allow the production of structured components with cavities, especially in the form of channels and undercuts, the

otherwise not be produced or only with considerable effort.

DE 199 00 597 A1 describes in this context a method for producing a sheet metal forming tool for small series production. For the production of the sheet metal forming tool, laser sintering or laminating are used as the method, the shaped bodies produced in this way being later infiltrated with a resin as part of a sheet metal forming tool in order to reduce the compressibility. From DE 10 2004 019 080 B3, in turn, a method is known in which individual moldings are contoured in their form by rolling or stamping tools in their surface. With such preformed bodies is then made a mold that is filled in, with the

Outer contour of the shape-forming body thus form quasi the formwork for the filling material, wherein the filler material is also contoured by tamping or rolling tools on the surface.

5

Under cavities, as has already been mentioned, not only cavities within the component understood, but also, for example, channels that extend from one end of the component to the next, such channels in any form in the

o Component can be arranged. Such cavities also count

Undercuts.

Sand is understood as meaning a substance which, with the binder, forms a

Can connect; For example, when using cement, 5 a hydraulic bond.

Concrete components are known in a variety of shapes and sizes. In the past, concrete was mainly used only in the construction of buildings, in particular buildings or bridges. In the course of time, however, the scope of application of concrete has certainly been

extended. It is already known to produce machine beds from concrete. Such machine beds, for example, are no longer made of a conventional concrete, as found in the construction industry, especially in the past use, but made of special concrete, 5 and in particular UHPC concrete mixtures. Such ultra-high-strength concretes are characterized, inter alia, by the fact that the components produced hereby have substantially smaller dimensions while achieving the same strength values as conventional concretes. This opens up the possibility of such concretes, as already stated not only for the

o manufacture of structures, but for components that are highly complex in structure, and not only in relation to their exterior Contour, but also with respect to the arrangement of cavities within the component.

Now it is known that concrete is poured into molds for shaping. But such forms have the disadvantage that, depending on the

Complexity of the component to be cast, the molds are enormously expensive.

This is because, much as in plastic injection molding, it is then necessary to provide molds with slides. The production of special molds for corresponding components requires, however, that i o due to the considerable mold costs with an existing form a considerable number of parts is made, since otherwise such

Form not amortized.

In this respect, so-called generative processes for the production of 15 components are already known. This includes, as has already been mentioned elsewhere, in particular the 3D printing technique.

In this respect, EP 2 269 808 A1 discloses the production of plastic bodies by way of 3D printing technology. For this purpose, a mold with a bottom adjustable in vertical direction is known, wherein the bottom is shifted to the layered structure of the body in the form down. The body can here after completion undercuts,

Have overhangs and cavities. It is known from EP 2 063 039 A1 to cast a concrete body in a mold, wherein prior to the casting process into the mold a hollow body, for. As a tube is used, which forms a recess in the concrete body for filling a pasty, curable material. The disadvantage here, however, that between the pipe on the one hand and the surrounding concrete on the other hand, as well as the curable material, a material

Connection in the sense of an infiltration can not take place, so this In the tube used mass can not function optimally as a reinforcement, as they, as already stated an immediate, material

Does not provide connection to the surrounding concrete.

5 The components produced by means of 3D printing technology as a generative process, which are essentially made of a mixture of sand and a binder, for example a cement or a polymer material or a mixture of cement and a

Polymer material, are characterized first by the fact that they are highly porous i o. This porosity of the workpiece requires a low

Strength. The reason for this is to be found in the fact that the workpiece is not solidified during manufacture, for example by shaking or pounding.

The object underlying the invention is therefore to solidify such a component produced, for example, by way of 3D printing technology.

To achieve the object, the features of claim 1, that the 0 produced by means of 3D printing porous component to increase the strength and density is soaked in a liquid, curable composition. "Soaking" is also understood when the liquid, curable composition is injected, infiltrated or filled into the component, for example into the at least one cavity

5 impregnation is porous, the component takes during the impregnation process a large amount of the liquid, curable mass, so that after

Completion of the impregnation process all voids or pores in the body are filled with this liquid, curable material. That is, the density of the body is thereby significantly increased, resulting directly in an increase in strength. It is further provided that the at least one channel at at least one end to the edge of Connects components, ie the component has an opening with respect to the channel. But this also means that the liquid, curable material passes through this opening in the interior of the component. In this

It has also proven to be advantageous that the at least one cavity designed as a channel is arranged in the component such that the component volume to be impregnated between the outer surface of the component and the at least one channel is substantially equal on all sides, so that in a predetermined time it is ensured that the complete component is completely saturated with a given porosity. In other words, this means that from any point of the component directly accessible to the liquid hardenable mass, the volume to be soaked in each direction must be in each direction

Is essentially the same. This ensures, as has also already been stated, that the component is completely soaked in a predetermined period of time.

Advantageous features and embodiments of the invention will become apparent from the dependent claims. Thus, it has proven particularly advantageous that the impregnation of the component takes place under vacuum. This means that the liquid, hardenable mass is virtually sucked into the porous component.

According to a further feature of the invention, it is provided that the liquid curable composition in the at least one channel after its solidification has a higher strength than the surrounding component. In this respect, it is possible, especially when this mass protrudes from the component after its solidification, that is beyond the component, this solidified mass can act as a reinforcement. The subject of the claim is that the component is made of a sand and a binder. This can after a

Embodiment, the binder is a hydraulic binder z. B. be a cement, in which case for the manufacture of the component of the sand and the cement as a dry mixture in layers, with a layer density of 0.05 to 5 mm, preferably of 0.01 mm, are deposited on a substrate, wherein after each layer the respective the last layer is wetted with water to allow the setting of the cement. In this case, the individual layers are applied to one another at specific time intervals, the time intervals being dependent on the progress of the setting process of the respective lower layer. Already from this it is clear that a body produced in such a way is porous, since a solidification of the individual layers essentially can not take place. In this respect, the final impregnation of the component in the curable and initially liquid mass leads to a significant increase in the strength of the component as a whole.

Alternatively, the binder may also be a liquid polymer material. The use of polymer materials in the production of concrete components is known, inasmuch as, for example, so-called polymer concretes are known, which are characterized by high strength. However, one is also a mixture of a sand and a

Polymer material produced body as porous as such a body, which is made of sand and a hydraulic binder, such as a cement. The reason for this is to be found in the same way that also here no mechanical hardening can take place in the layered structure of the component.

The liquid curable composition is, in particular, the use of a cement slurry or a liquid polymer material especially one with fibers, z. As plastic and / or metal fibers offset cement slurry or polymer material in question.

Possibly. also comes a combination of polymer material and

Cement sludge into consideration. This depends on the intended use of the corresponding component, and finally on the desired strength. It is essential here that the liquid curable composition preferably has a higher strength after hardening than the surrounding material, so that the hardened material present in the channels can function as reinforcement for load transfer in the case of external forces acting on the body. It has proved to be advantageous if the polymer material is a resin, since such resins are particularly suitable for soaking such porous materials.

With reference to the drawings, the invention will be explained in more detail below by way of example with reference to the production of a concrete component.

Fig. 1 shows schematically a concrete component of the invention

Art;

Fig. 2 shows a view from above of the concrete part of FIG. 1; shows a formation of the cavity in a view of the

Concrete part according to the line IIa / IIa of Fig. 1;

Fig. 3 shows a device for producing a concrete component in a schematic representation;

Fig. 4 shows a side view of Fig. 3; As shown in FIG. 1, a concrete component is designated 1. The concrete component 1 shows three superimposed recesses 2, which serve to receive a reinforcement. The one recess is intended to extend in three spatial directions in order to make it clear which possibilities the method according to the invention opens up.

From Fig. 2 and Fig. 2a, the structure in the region of the upper and middle recess 2, which extends obliquely in the concrete component. Visible, the individual layers 5 of the concrete component in the region of the recess 2 are formed stepwise outward running out, then back up after reaching the lateral apex of the approximately circular, elliptical or square recess

converge. The preparation of the recess 2 takes place in

Individual in that, as already stated, the individual layers of the dry mixture are deposited on each other. The layers are wetted with water only where the layer is to set to form the concrete component. In this respect are also in the

cavities formed from a dry mixture, wherein the layers are supported above the horizontal apex of a substantially circular recess on the underlying layers, which have not been sprayed with water. That in the

The recess located dry, not hardened mixture trickles when receiving the concrete part of the pad out of the recess or it is blown or sucked out.

The device according to FIG. 3 is characterized by one in three

Spatial directions movable discharge head 10, which is designed as a discharge channel and which is arranged on a cross member 21. The traverse 21 is held by two supports 22 which are displaceable on rails 23 in the direction of the arrow 25. The traverse 21 is held vertically movable by the supports 22 (arrow 35). The Traverse 21 forms with the Rails 23 and the supports 22, the frame 20. At the discharge head 10 is designed as a spray head further discharge head 27, which serves for the discharge of water.

5 The discharge tray 27 movably arranged by the traverse in the direction of the arrow 30 and the discharge head 27 attached to the discharge chute and designed as a spray head are thus movable in three spatial directions.

The discharge head 10 designed as a discharge channel has a slot-like discharge opening 11 for the mixture of hydraulic binder and sand on the underside. The spray head serves the contour sharp

Spraying water.

The procedure for producing a structured concrete part is as follows: First, a layer of the mixture of

hydraulic binder and sand applied to the substrate 7 through the discharge head 10 designed as a discharge channel. The layer is in plan view z. B. rectangular. Then the layer is sprayed with water according to the desired contour. After the shift

0 has set or at least partially set so far that it is stiff, in turn, a layer of the dry mixture in a rectangular shape is applied to this first layer. Then this layer is sprayed with water according to the desired contour of this layer. The whole process is continued in layers until the body is finished as a concrete part. Then the concrete part is lifted off the base. The unbound mixture dissolves from the concrete part or concrete body; Cavities in the concrete part can be blown out with compressed air. In the cavities 2, a curable composition is introduced, which is able to absorb tensile forces after curing. As curing of mass here comes z. B. a plastic z. As a resin in question.

The production of a component by means of a binder in the form of a polymer material is similar to the production of such a component with a mixture of sand and a cement. In this respect, as well as in the manufacture of a component with sand and a

Binders made of a polymer material are repeatedly applied to individual layers of sand on a substrate, and these are then sprayed with the liquid polymer material, such as a resin, according to the desired contour. After solidification of each lower layer, another layer of sand is applied. Also, the resulting body or the component is characterized by a high porosity, which increases the strength by impregnating a curable liquid mass, for. As a polymer material, and in particular also a resin and in particular under vacuum can be increased.

LIST OF REFERENCE NUMBERS

1 concrete part

2 recess

5 individual layers

7 base

10 discharge head

1 1 discharge opening

20 frame

21 traverse

22 support

23 rail

25 direction indication (arrow)

Discharge

Direction indication (arrow) Direction indication (arrow)

20

Claims

Claims:

1. Generative method for producing a component with at least one channel by 3D printing technology with a sand and a

Binder, wherein the at least one channel protrudes at at least one end to the edge of the component,

characterized,

in that the porous component produced in the course of the 3D printing technique is impregnated in a liquid curable composition for filling the pores, the at least one channel being introduced into the component in such a way that the component volume to be impregnated is between the components outer surface of the component and the at least one channel is the same on all sides.

2. Generative method according to claim 1,

characterized,

that as a binder, a hydraulic binder, for. B. cement is used.

3. Generative method according to claim 2,

characterized,

that the sand and the hydraulic binder are deposited as a dry mixture in layers on a substrate, wherein after each layer, the respective layer is wetted with water.

4. Generative method according to claim 3,

characterized,

that the individual layers are applied to each other at certain time intervals, with the time intervals are dependent on the progress of the setting process of the respective lower layer.

5. Generative method according to claim 3 or 4,

characterized,

that layers with a thickness of 0.05 to 5 mm, preferably of 0.1 mm are produced.

6. Generative method according to one of the preceding claims, characterized

in that a liquid polymer material is used as binder.

7. Generative method according to claim 6,

characterized,

that the sand is applied with the liquid polymer material as a mixture in layers on a substrate.

8. Generative method according to claim 6,

characterized thereby,

that first the sand is applied in layers on a substrate, wherein each layer is wetted with a liquid polymer material.

9. Generative method according to one of the preceding claims, characterized

that a cement slurry is used as the liquid, hardenable mass.

10. Generative method according to one of the preceding claims, characterized

that the cement slurry is mixed with a polymer material.

11. Generative method according to one of claims 7 to 10, characterized

that a resin is used as the polymer material.

12. Generative method according to one of the preceding claims, characterized in that

that the impregnation of the component takes place under vacuum.

13. Generative method according to one of the preceding claims, characterized

that the liquid, curable composition in the at least one channel after its solidification has a higher strength than the surrounding component.

14. Generative method according to one of the preceding claims, characterized

that the liquid, curable composition is mixed with a proportion of fibers of plastic and / or metal.