WO2021221545A1

WO2021221545A1 - Straight-flow extruder for building mixes

Info

Publication number: WO2021221545A1
Application number: PCT/RU2021/050114
Authority: WO
Inventors: Александр Владимирович МАСЛОВ
Original assignee: Общество С Ограниченной Ответственностью "Амт"
Priority date: 2020-04-28
Filing date: 2021-04-28
Publication date: 2021-11-04
Also published as: RU2020115021A; RU2020115021A3

Abstract

The invention relates to 3D construction printers for manufacturing construction components. A straight-flow building mix extruder for a 3D printer consists of: a body having a device for attaching the extruder to the working members of a printer; loading apertures for building material; and a nozzle with an outlet aperture for extruding said building material. Incorporated into the bottom part of the body is a building mix metering device for regulating the amount of building mix during the formation of a printed layer. The extruder contains a mixing device fastened inside the body and provided with metering devices for building mix ingredients, said metering devices being connected to feed systems. The mixing device contains an air cutoff valve. The building mix metering device is configured in the form of a screw conveyor or a gerotor pair connected to a drive. The ingredients for preparing a building mix are supplied separately via the feed systems, inter alia dry ingredients, which are supplied via one feed system with the aid of compressed air, and water, which is supplied via a second feed system. The feed system for supplying dry ingredients with the aid of compressed air can be a pneumatic feed system. The invention makes it possible to increase the throughput of a printer, improve printing accuracy and provide better placing of building mixes.

Description

STRAIGHT MIXTURE EXTRUDER

Technology area

The invention relates to the construction field, namely to construction 3D printers, in particular to extruders of building mixtures intended for installation on construction 3D printers of volumetric printing of various layout schemes for the manufacture of building structures, including for the construction of residential buildings, buildings and structures of various purpose, production of parts and elements of buildings, parts of building structures, building materials and other products of simple and complex geometric shapes using additive technology.

State of the art

The basis of all known methods of 3D printing are the following steps: the formation of cross-sections of the manufactured object, the layer-by-layer imposition of these sections and the combination of layers, with the creation of a given geometry of the product, corresponding to a computer 3D model.

Depending on the selected technology of three-dimensional printing of products, various materials can be used: metal and ceramic powders, liquid resins, wax, plastic, various sheet materials, composite materials (from cellulose compounds, special fibers and other additives, a mixture of foundry sand and additives), construction mixtures based on cement, gypsum, chamotte clay.

Construction ZO-printing can be carried out in different ways and using various materials, which are based on the principle of layer-by-layer creation (growth) of a solid object, as a result of which the object is formed by layer-by-layer laying of building material to the height of the formed layer.

The following materials are used for printing building structures: cement (Portland cement), sand (silicon dioxide, olivine, chromite, zircon, alumina, mullite, quartz glass, chamotte), gypsum, modifying and anti-freezing additives, plasticizers, fiber fibers, accelerators (retarders) of hardening , water, and composite materials based on lignin and cellulose.

In all known cases, regardless of the design of the printer (gantry, with angular coordinates based on robots - manipulators), construction printers are not equipped with extruders that allow the simultaneous use of automated feeding of the components of the building mixture into the extruder separately, including binder and nonmetallic materials in dry form, including with the use of pneumatic feeding, dose and mix ingredients, introduce plasticizing and other additives immediately before the extrusion of the building mixture using actuators based on CNC, use construction mixtures based not only on cement binder.

It is known from the prior art to form (extrude) a wall with internal ribs (see [1] PCT application N ° W02007050972, IPC В28В 1/16, publ. 03.05.2007). The published application describes an extrusion nozzle that includes three outlets with a controller allowing the extruded material to be guided into three outlets.

The disadvantages of this analogue are:

- supply of the mixture to the extruder only in finished form, there is no possibility of supplying materials separately;

- lack of built-in mortar batchers integrated into the extruder, which allows to regulate the amount of building mixture ingredients during mixing. Dispensers can contain mechanisms based on drive and CNC control elements;

- the absence of a mixing device to avoid delamination and clumping of the building material used for printing during transport to the extruder;

- lack of additional communications for the introduction of plasticizing and other additives.

From the prior art, a ZO printer for underwater printing of objects is known (see [2] RF application N ° 2016142836, IPC E02D 15/00, publ. 03.05.2018), containing a vehicle, a source of concrete, a stock of reinforcing means and a manipulator, on the final link which has a print head containing a screw chamber, inside which there is a screw screw connected to a drive, and the initial part of the screw chamber is connected to a concrete pipeline, and a nozzle is installed in the outlet part of the screw chamber.

The disadvantages of this analogue are:

- lack of built-in mortar dispensers integrated into the extruder, allowing to regulate the amount of building mixture ingredients during mixing;

- lack of additional communications for the introduction of plasticizing and other additives. A device for erecting a monolithic building is known from the prior art (see [3] RF patent N ° 2683447, IPC E04C 5/07; C04B 7/52, publ. 03/28/2019), including a 3D printer with a dispensing head for layering concrete filament mixture in the design position, connected to the unit for preparation and supply of concrete mixture.

The disadvantages of this analogue are:

The closest analogue to the claimed invention in terms of a set of features taken as a prototype is a method and device for supplying cement materials (see [4] PCT application N ° WO2013064826, IPC В28В 17/00, В28В 3/20, В28В 3/26, publ. 05/10/2013). The application provides a description of extruding a finished cement-based material from a tank through a nozzle. In this solution, it is proposed to place the extruder only on the manipulator, building mixtures are supposed to be supplied to the extruder by pumps, ready-made, mixed, only on the basis of a cement binder.

The simplified design of the extruder for building mixtures for a 3D printer does not provide for the use of:

- separate transport systems (including pneumatic feeding of dry materials) for the ingredients of the building mixture with automated loading into the extruder;

- dispensers for ingredients of building mixtures, which allows you to adjust the proportions of ingredients when mixing building mixtures;

- a mixing device that allows you to prepare a mixture (mix ingredients) immediately before extrusion, to avoid delamination and clumping of the building material, reducing the time from kneading to extrusion;

- additional communications for the introduction of plasticizing and other additives;

- ready-mix dispenser.

The essence of the invention

The technical problem facing the invention is to eliminate the disadvantages of analogs and expand the functionality.

The technical result of the claimed invention is a significant increase in printer productivity, increased printing accuracy and quality of stacking building mixtures, reducing the time for flushing and routine maintenance of equipment.

According to the invention, the technical problem is solved, and the technical result is achieved due to the fact that the direct-flow extruder of building mixtures for a 3D printer consists of a body (container) with a fastening device that allows the extruder to be fixed on the printer actuators, holes for loading building material, a nozzle with an output a hole for extruding building material, while a mortar dispenser is integrated into the lower part of the housing, which allows you to regulate the amount of building mixture during the formation of the printed layer, and the extruder contains a mixing device fixed in the housing with dispensers for ingredients of building mixtures connected to transport systems.

Also, the technical problem is solved, and the technical result is achieved due to the fact that the mixing device contains an air cut-off valve.

Also, the technical problem is solved, and the technical result is achieved due to the fact that the batcher of building mixtures is made in the form of a screw or a gerotor pair connected to a drive.

Also, the technical problem is solved, and the technical result is achieved due to the fact that the ingredients for the preparation of the construction mixture are supplied separately through transport systems, including dry ingredients by means of compressed air through one transport system, and water through the second transport system.

Also, the technical problem is solved, and the technical result is achieved due to the fact that the transport system for supplying dry ingredients by means of compressed air can be a pneumatic transport system.

Brief Description of Drawings

FIG. 1 is a side view (in section) of a straight-through mortar extruder for a 3D printer.

FIG. 2 - top view of the extruder of building mixtures for a 3D printer.

FIG. 3 - a diagram of the organization of the supply of liquids (including water) and pneumatic supply of dry ingredients to the direct-flow extruder.

FIG. 4 - side view (in section) of the mixing device.

The following positions are indicated in the figures:

1 continuous flow extruder body;

2 fastening device;

3 holes for loading (feeding) the ingredients of the building material (building mixture) into the extruder;

4 dispensers for building mixture ingredients; 5 - mixing device;

6 - dispenser (auger or gerotor pair) for the construction mixture;

7 - nozzle;

8 - transport systems (including pneumatic transport systems for dry ingredients);

9 - drive of the construction mixture batcher (auger or gerotor pair);

10 - printed design;

11 - printer;

12 - air cut-off valve;

13 - water (supply);

14 - air (supply);

15 - dry bulk ingredients (feed).

Implementation of the invention

The direct-flow extruder of building mixtures for a 3D printer is designed for batching, mixing the ingredients of the building mixture directly in the mixing device of the extruder before extruding the building material, followed by layer-by-layer, automatic stacking of layers from mixtures (building material) based on cement, gypsum, chamotte clay.

The straight-through extruder consists of a body (1) (container) with a fastening device (2), holes (3) for loading ingredients of a building material, a nozzle (7) with an outlet for extruding a building material. The fastening device (2) allows to constructively fasten the extruder to the actuators of the 3D printer (11) of various layout schemes: operating in Cartesian or angular coordinates, or to have the design of a robot-manipulator.

The extruder also contains a mixing device (5) located in the housing (1), as well as ingredient dispensers (4) located in front of the mixing device (5), allowing to maintain the proportions of the building mixture with great accuracy and quickly change them. The mixing device (5) makes it possible to prepare the building mixture immediately before its extrusion, to introduce plasticizing and other additives into the mixture, to avoid delamination and clumping of the building material used for printing.

Structurally, the ingredient dispensers (4) for building mixtures can be located outside the extruder body, incl. in front of transport systems (8), which are also part of the extruder. For example, it is convenient to meter dry components of the mixture (binder and nonmetallic materials) before feeding into the extruder, in which case the dispenser will be located in front of the transport (including pneumatic transport) system of the printer. Liquid ingredients incl. water (13) is supplied to the mixing device (5) and there it is mixed with dry ingredients (14) (binding, non-metallic materials), which in turn are fed to the mixing device using compressed air (15) through pneumatic conveying systems. This air is removed from the mixing device by means of a shut-off valve (12), which does not allow the passage of ingredients, and located in the housing of the mixing device. The gross mixture is poured into the dispenser (6) of building mixtures, integrated into the lower part of the housing (1), made in the form of a screw or a gerotor pair, which allows to regulate the amount (supply) of the extruded building mixture after its preparation during the formation of the printed layer of the printed structure (10) driven in rotation by the drive (9).

Additionally, a straight-through extruder can contain mechanisms based on drive and CNC control elements. So in the claimed invention, the feed rate of the mixture through the batcher (6) of building mixtures is controlled depending on the speed of movement of the extruder, and the proportions and amount of ingredients supplied to the extruder are controlled in proportion to the extrusion.

The technical problem is solved, and the technical result is achieved due to the fact that:

• Extruders of a similar design can be used on all types of construction printers, regardless of the layout (gantry, with angular coordinates based on robots - manipulators);

• The ingredients of the building mixture are fed into the extruder separately and mixed immediately before the extrusion of the building mixture;

• Transportation of binder and non-metallic materials is carried out using pneumatic conveying systems, which significantly reduces the time for washing and maintenance of printers;

• During kneading, plasticizing and other additives may be added to the mixture;

• All feeding systems are equipped with metering devices for ingredients of building mixtures, which allows you to accurately maintain the proportions of the building mixture and change them;

• The straight-through extruder contains a mixing device;

• The batcher of ready-made construction mixtures is made in the form of an auger or a gerotor pair.

The device works as follows.

The ingredients of the building mixture are loaded (fed) into the housing (1) of the extruder, which is attached to the printer actuators by means of the fastening device (2), through the holes (3) for loading (feeding) the ingredients of the building material (building mixture) into the extruder. The amount of each ingredient are dosed using ingredient dispensers (4) located either in the extruder housing (1) or in front of the transport systems (8). After feeding, the ingredients of the building mixture are mixed in a mixing device (5), which allows to prepare the building mixture immediately before its extrusion, to introduce plasticizing and other additives into the mixture, to avoid delamination and lumping of the building material used for printing. Next, the finished mixture is extruded by means of a mortar dispenser (6), made in the form of a screw or a gerotor pair, driven in rotation by a drive (9). The batcher (6) of building mixtures allows you to adjust the amount of extruded building mixture during the formation of the printed layer, the printed structure (10).

The causal relationship between the technical result and the essential features of the claims is as follows:

- achieving a high surface quality and increasing the mechanical characteristics of printed objects when printing buildings and structures by improving the characteristics of the building mixture, achieved by installing ingredient dispensers (4), which allow to observe the proportions of the building mixture with great accuracy and quickly change them.

- achieving high accuracy of printed objects when printing buildings and structures by installing a dispenser (6) of a construction mixture, which allows to regulate the amount of a construction mixture during the formation of a printed layer;

- expanding the functionality of the extruder of building mixtures for a 3D printer, which may contain mechanisms built on drive and CNC control elements, which allow you to adjust the feed rate of the mixture through the batcher (6) of building mixtures depending on the speed of movement of the extruder and change the proportions and amount supplied to the extruder ingredients in proportion to extrusion;

- reducing the time for flushing and servicing the printer, incl. transport systems due to the use of separate supply of dry ingredients (15) by means of compressed air (14) and water (13).

Claims

CLAIM

1 . Direct-flow extruder of building mixtures for a 3D printer, consisting of a body (1) with a fastening device (2) that allows you to fix the extruder on the printer's actuators, holes (3) for loading building material, nozzles (7) with an outlet for extruding building material, at the same time, a dispenser (6) of building mixtures is integrated into the lower part of the housing (1), which allows to regulate the amount of building mixture during the formation of the printed layer, characterized in that it contains a mixing device (5) fixed in the housing (1) with dispensers of ingredients (4) of building mixtures connected to transport systems (8).

2. A co-current extruder according to claim 1, characterized in that the mixing device (5) comprises an air cut-off valve (12).

3. Direct-flow extruder according to claim 1, characterized in that the metering unit (6) for building mixtures is made in the form of a screw or gerotor steam connected to a drive (9).

4. Direct-flow extruder according to claim 1, characterized in that the ingredients for the preparation of the construction mixture are fed separately through transport systems (8), including dry ingredients (15) by means of compressed air (14) through one transport system, and water (13) through second transport system.

5. Co-current extruder according to claim 4, characterized in that the transport system for supplying dry ingredients by means of compressed air can be a pneumatic transport system.