CN107042632B - Reducing nozzle and extruding device for building 3D printing - Google Patents

Abstract

The invention discloses a variable-diameter nozzle for building 3D printing, comprising: a rotating dial, a bottom plate, four linear guide rails, four sliders and four right-angle moving pieces; , the rotary dial drives the four driving parts to rotate synchronously through the four driving slots, and then drives the four sliders to slide synchronously along the four linear guide rails, and the four sliders drive the four right-angle moving pieces to move relative to each other synchronously, so that it can be printed In the process, the size of the square nozzle aperture is changed by changing the relative positions of the four right-angle moving pieces. When printing a large area, the diameter of the square nozzle can be enlarged, and the output speed can be increased. It is not necessary to repeat the printing many times, and it is not necessary to prolong the residence time of the nozzle, thereby improving the printing efficiency.

Description

A variable-diameter nozzle and extrusion device for architectural 3D printing

technical field

The present invention relates to the field of architectural 3D printing, and more specifically, relates to a variable-diameter nozzle and extrusion device for architectural 3D printing, which are used for extruding and curing cement mortar masonry 3D printing.

Background technique

3D printing technology is an additive manufacturing technology that directly manufactures three-dimensional structures from digital models. It originated in the 1980s and integrates cutting-edge technologies in many disciplines such as information technology, electromechanical control technology, and material science and technology. It has been successfully used In aerospace, automotive, biomedical and other industries. 3D printing technology has brought a new idea to the development and transformation of the construction industry, and has strong application potential in solving the problems of environmental pollution, resource waste, and shortage of human resources that plague the traditional construction industry. Specifically, it mainly includes:

1) There is no need for formwork, reducing the demand for artificial labor, thereby reducing construction costs;

2) Relying on machine automation construction methods greatly shortens the on-site construction time and improves construction efficiency;

3) The additive manufacturing method reduces material waste and construction waste discharge, effectively protecting the environment;

4) Digital design breaks through the existing design freedom and realizes more complex architectural and structural design.

In modern engineering construction, cement mortar (concrete) is the most widely used type of composite building material. Using cement mortar as a raw material for 3D printing is currently the mainstream choice for construction 3D printing technology based on extrusion curing process. This type of architectural 3D printing hardware system mainly includes control devices, motion devices, feeding devices and extrusion devices. Among them, the extrusion device is directly related to the molding quality of printed building product components and is very important. However, the existing such architectural 3D printing extrusion devices generally have some deficiencies in practical applications, mainly including the following aspects:

(1) The size of the nozzle of the existing extrusion device is fixed during the printing process. When a constant small-diameter nozzle is used to process complex large graphics, it is often necessary to perform multi-pass processing, or to stay longer in a larger area. It takes a long printing time to complete the printing and manufacturing, which directly leads to low printing efficiency.

(2) The nozzle of the existing extrusion device is circular, and the outer surface of the printed component product has obvious layered textures with radians, especially at the corners and positions where the curvature changes significantly, which cannot meet the original design quality requirements .

(3) The existing extrusion device does not take into account the need for equipment cleaning after printing, especially the disassembly and cleaning of the nozzle device is very inconvenient. Due to the use of tubular nozzles, it is often impossible to completely clean the inside of the nozzle, resulting in some residual material deposits. If it is light, it will affect the molding quality in the subsequent use process, and if it is heavy, it will directly cause damage to the device.

Contents of the invention

Aiming at the above defects or improvement needs of the prior art, the present invention aims to provide a spray head, which solves the problem of low printing efficiency and difficulty in forming Quality requirements, technical problems of inconvenient disassembly and cleaning.

In order to achieve the above purpose, according to one aspect of the present invention, a variable-diameter nozzle for architectural 3D printing is provided, including: a rotating dial, a bottom plate, four linear guide rails, four sliders and four right-angle moving pieces;

There are four drive slots on the circumference of the rotary dial;

The bottom plate is located under the rotary dial; four linear guide rails are distributed in a square and installed on the bottom plate;

The four sliders are slidably installed on the four linear guide rails one by one, and each of the four sliders is provided with a driving part, a total of four driving parts, which are inserted into the four driving grooves in one-to-one correspondence;

The four right-angled moving pieces are located under the bottom plate, and are installed on the four sliders one by one, and the right-angled sides of the four right-angled moving pieces are attached in pairs to form a square nozzle in the middle; among them,

Both the bottom plate and the rotary dial are provided with through holes corresponding to the square nozzles for feeding;

When the rotary dial and the bottom plate rotate relative to each other, the rotary dial drives the four driving parts to rotate synchronously through the four driving grooves, and then drives the four sliders to slide synchronously along the four linear guide rails, and the four sliders drive the four right-angled moving parts. The relative movement of the slices synchronously changes the caliber of the square nozzle.

Further, a limiting plate is included; the limiting plate has a plane, which is close to the four right-angled moving pieces, so as to ensure that the four right-angled moving pieces are always on the same plane during the movement; the limiting plate is provided with a corresponding square Nozzle through hole.

Further, it includes four bearings, which are arranged in the four drive slots in one-to-one correspondence; the four drive parts are all shaft-shaped structures, and are inserted in the four bearings in one-to-one correspondence.

On the other hand, in order to achieve the above object, the present invention also provides an extrusion device for building 3D printing, which includes the above-mentioned variable-diameter nozzle.

Further, the variable-diameter spray head includes a first rotating sleeve and a first motor, the first motor is used to drive the first rotating sleeve to rotate; the rotating dial is arranged on the first rotating sleeve and rotates synchronously with the first rotating sleeve .

Further, the extrusion device includes a rotating module, the rotating module includes a second rotating sleeve and a second motor; the second motor is used to drive the second rotating sleeve to rotate, and the bottom plate is arranged on the second rotating sleeve;

The rotating dial, the bottom plate, the first rotating sleeve and the second rotating sleeve are coaxially arranged, and the first rotating sleeve is sleeved on the outside of the second rotating sleeve.

Further, the extrusion device includes a stirring module and a feeding module; the stirring module, the feeding module, the rotating module and the variable-diameter nozzle are arranged sequentially from top to bottom;

The stirring module includes a third motor, a stirring impeller and a hopper; the third motor is connected to the stirring impeller, the stirring impeller is placed in the hopper, and the lower part of the hopper is the material outlet;

The feeding module includes a fourth motor, a screw, and a screw pump stator; the fourth motor is connected to the screw, the screw pump is installed at the material outlet of the lower part of the hopper, and the upper part of the screw is located in the screw pump;

The upper end of the second rotating sleeve of the rotating module is connected with the screw pump, and the lower part of the screw is located in the second rotating sleeve.

Further, the third motor is connected to the stirring impeller through the third rotating sleeve, and the connecting shaft of the fourth motor and the screw is arranged coaxially with the third rotating sleeve and located inside the third rotating sleeve.

Further, the rotation module also includes a first motor mounting base, and the first motor mounting base is fixed on the outside of the second rotating sleeve; the first motor and the first rotating sleeve are both installed on the first motor mounting base, and The sleeves move synchronously; the first rotating sleeve can rotate relative to the first motor mount.

Further, the limiting plate is installed on the first motor mounting base and moves synchronously with the first motor mounting base, and the bottom plate is located between the limiting plate and the first motor mounting base.

Generally speaking, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:

1. The present invention is composed of four right-angle moving pieces to form a nozzle, and the size of the nozzle diameter can be changed by changing the relative positions of the four right-angle moving pieces during the printing process. When printing a larger area, the nozzle diameter can be enlarged. To increase the output speed, it is not necessary to repeat the printing many times, and it is not necessary to prolong the residence time of the nozzle in this place, thereby improving the printing efficiency;

2. The invention adopts a square nozzle, which can significantly alleviate or even eliminate the layered texture with radians on the outer surface of the printed component product, especially at the corners and positions where the curvature changes significantly, the improvement effect is obvious, and the molding quality is significantly improved;

3. The square nozzle in the present invention is composed of four right-angle moving pieces, which is easy to disassemble. Compared with the traditional tubular nozzle, it is difficult to clean the inside. The present invention can directly clean the surface of the disassembled right-angle moving piece. Easy and thorough cleaning;

4. The device of the present invention adopts a modular design, and all four functional modules can be disassembled, which is convenient for maintenance and cleaning.

Description of drawings

Fig. 1 is the three-dimensional schematic diagram of the preferred embodiment of extruding device of the present invention;

Fig. 2 is a partial exploded and perspective view of Fig. 1;

Figure 3 is an exploded view of Figure 1;

Fig. 4 is an overall assembly diagram of the rotating module and the variable-diameter nozzle;

Fig. 5 is a schematic diagram of the assembly method of the rotating module and the variable-diameter nozzle;

Fig. 6 is an exploded view of a bottom view of Fig. 5;

Fig. 7 is an exploded view of a top view of Fig. 5;

Fig. 8 is a schematic cross-sectional view of the variable-diameter nozzle assembled with the second rotating sleeve;

Fig. 9 is a schematic diagram of the caliber change process of a square nozzle;

Fig. 10 is the schematic diagram of stirring module;

Fig. 11 is the schematic diagram of feeding module;

Fig. 12 is a schematic diagram of an auxiliary structural member;

Fig. 13 is a block diagram of the working principle of the extrusion device of the present invention.

Throughout the drawings, the same reference numerals are used to designate the same elements or structures, wherein:

1-variable nozzle

11-rotary dial 111-drive slot 112 baffle

113-bearing 114-limiting ring 12-bottom plate

13-Linear guide 14-Slider 141-Drive part

15-Rectangular moving piece 151-Square nozzle 16-Limiting plate

17-First motor 18-First rotating sleeve 19-First motor mount

2-rotation module

21-Second Motor 22-Second Rotary Sleeve 23-First Fastener

24-Second Motor Mount 25-Second Fastener

3- Stirring module

31-the third motor 32-stirring impeller 33-hopper

34-the third rotating sleeve 35-sprocket mechanism

4- Conveyor module

41-the fourth motor 42-coupling 43-screw

44-Screw pump stator 45-Linkage shaft

5- Auxiliary structural parts

51-main body bracket 52-third motor mount 53-fourth motor mount

54-Hopper mounting base 55-First protective cover 56-Second protective cover

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

In order to overcome the problems of poor appearance quality, low printing efficiency, inconvenient equipment disassembly, cleaning and maintenance of the existing 3D printing of buildings based on extrusion curing, the present invention proposes an extrusion device for 3D printing of buildings.

1-3 are schematic perspective views and exploded views of the extrusion device. The extrusion device is installed on the lifting beam of the gantry-type three-axis coordinate machine (not shown), the moving device of the entire 3D printing system. It consists of four modules and other auxiliary structural parts 5. The stirring module 3, the material conveying module 4, the rotating module 2 and the variable-diameter nozzle 1 are arranged sequentially from top to bottom. The modular design makes the extrusion device have better disassembly and assembly performance, which is convenient for cleaning and maintenance.

In the present invention, the cooperative work of the variable-diameter nozzle and the rotating module is the key to realizing intelligent extrusion of materials and improving processing efficiency. Please refer to Figure 4-8, which is the assembly and disassembly of the variable-diameter nozzle 1 and the rotating module 2 of the present invention schematic diagram. The working principle, process and specific structure of these two modules will be described below in conjunction with Figures 4-8.

The variable-diameter spray head 1 includes a rotary dial 11 , a bottom plate 12 , four linear guide rails 13 , four sliders 14 and four right-angle moving pieces 15 . Four drive grooves 111 are defined in the circumferential direction of the rotary dial 11 . The base plate 12 is located below the rotary dial 11 , and four linear guide rails 13 are arranged in a square shape and installed on the base plate 12 . The four sliders 14 are slidably installed on the four linear guide rails 13 one by one, and each of the four sliders 14 is provided with a driving part 141, a total of four driving parts 141 are inserted into the four driving slots 111 in one-to-one correspondence middle. Four right-angled moving pieces 15 are located below the base plate 12, and are installed on the four slide blocks 14 in one-to-one correspondence, and the right-angled sides of the four right-angled moving pieces 15 are bonded in pairs to form a square nozzle 151 in the middle (as shown in Figure 9 ).

Wherein, the bottom plate 12 and the rotary dial 11 are provided with through holes corresponding to the square nozzles 151 for feeding. When the rotary dial 11 and the bottom plate 12 rotate relative to each other, the rotary dial 11 drives the four driving parts 141 to rotate synchronously through the four driving grooves 111, and then drives the four sliders 14 to slide synchronously along the four linear guide rails 13, and the four The slider 14 drives the four right-angle moving pieces 15 to move synchronously relative to each other, thereby changing the diameter of the square nozzle 151 .

The variable-diameter spray head also includes a limiting plate 16, which has a plane that is close to the four right-angle moving pieces 15 to ensure that the four right-angle moving pieces 15 are always on the same plane during the movement; the limiting plate 16 is provided with a through hole corresponding to the square nozzle 151 .

In order to make the rotary dial 11 drive the slider 14 more smoothly, the variable-diameter spray head also includes four bearings 113, which are arranged in the four driving slots 111 one by one; the four driving parts 141 are all shaft-shaped structures, and are inserted in one-to-one correspondence. Four bearings 113 are included. A baffle 112 is arranged inside the driving groove 111 , and a limit ring 114 is arranged on the outer edge of the rotary dial, both of which are to ensure that the bearing 113 is located in the driving groove 111 . In other embodiments (not shown), the driving groove 111 can also be directly configured as a waist-shaped blind hole, and the bearing 113 is placed therein, so that the limiting ring 114 does not need to be provided.

The variable-diameter nozzle of the present invention has a centering and variable-diameter structure, which is different from the overlapping design of camera shutters. The variable-diameter nozzle of the present invention can be called a "translational splicing centering and variable-diameter structure". The structure consists of a number of right-angle moving pieces 15 with the same shape and size spliced in pairs to form a group of centrally symmetrical variable-diameter right-angle moving pieces 15 closely arranged on the same horizontal plane, and each right-angle moving piece 15 is rigidly connected with a slider 14 , each slider 14 can move along a linear guide rail 13, that is, the right-angle moving piece 15, the slider 14, and the linear guide rail 13 correspond one-to-one, and the linear guide rail 13 is located on a bottom plate 12, and the bottom plate 12 is connected to the rotary module 2 through bolts. The second rotating sleeve 22 is rigidly connected. In other embodiments (not shown), the shape and size of the four right-angle moving pieces 15 can be different, as long as the four right-angle parts are arranged oppositely to form a square nozzle 151 .

The reducing nozzle 1 also includes a first motor 17, a first rotating sleeve 18 and a first motor mount 19, the first motor 17 and the first rotating sleeve 18 are installed on the first motor mount 19, and the first rotating The sleeve 18 can rotate relative to the first motor mounting base 19 driven by the first motor 17 . In this embodiment, the rotating dial 11 is fastened to the first rotating sleeve 18 by bolts. In other embodiments (not shown), the manner in which the rotating dial 11 is arranged on the first rotating sleeve 18 is also Can be integrally formed. The limiting plate 16 is installed on the first motor mounting base 19 and moves synchronously with the first motor mounting base 19 , and the bottom plate 12 is located between the limiting plate 16 and the first motor mounting base 19 . In other embodiments (not shown), if the position of the bearing 113 is limited by directly using the lower end surface of the first rotating sleeve 18 to cooperate with the slider 14 , then the baffle plate 112 may not be provided.

When the rotation signal is received, the first motor 17 drives the first rotating sleeve 18 to rotate, thereby driving the rotary dial 11 to rotate, and then moves all the sliders 14 to move synchronously along the linear guide rail 13, and all the right-angle moving pieces 15 are in the corresponding Driven by the sliding block 14, it passively performs centrifugal or centripetal movement, and displaces each other along the contact surface. A small hole with a central symmetrical shape is formed in the central area surrounded by four right-angled moving pieces 15. The shape of the small hole is determined by the right-angled moving piece 15. The contact surface determines that the aperture of the small hole is determined by the dislocation distance of the right-angle moving piece 15, and the center of the small hole remains constant and does not rotate. The small hole is the square nozzle 151, that is, since the geometric center of the square nozzle 151 is located on the rotation axis of its rotation, the square nozzle 151 can be centered and reduced in diameter.

Please refer to Fig. 9, which is the diameter reduction process of the square nozzle 151. In Fig. 9, when the rotary dial 11 (not shown in Fig. 9) rotates counterclockwise, the four right-angle moving pieces 15 linearly slide counterclockwise, and the square The diameter of the nozzle 151 gradually decreases in the order of d ₁ , d ₂ , d ₃ until it reaches 0, that is, it is closed. When the rotary dial 11 is turned clockwise, the diameter of the square nozzle 151 gradually increases in the order of d ₃ , d ₂ , and d ₁ . The process of increasing and shrinking is reversible, therefore, the variable-diameter nozzle of the present invention can control the right-angle moving piece 15 to slide along the bottom plate 12 in real time and automatically adjust the square nozzle 151 according to the geometric shape of the processed figure and the planned square nozzle 151 scanning route. The caliber size of the nozzle changes within a preset range (for example, 0mm~20mm), so that different processing positions always maintain the most effective and reasonable nozzle size.

Please refer to Figures 4 and 5. The rotation module 2 is used to realize the rotation of the square nozzle 151 in the horizontal plane. Specifically, the rotation module 2 cooperates with the variable-diameter nozzle to rotate and adjust the square in real time according to the change of the tangential direction on the curved printing path. The angle of the nozzle 151 is such that it always adapts to changes in the curvature of the scanning travel path.

The rotating module 2 includes a second motor 21 , a second rotating sleeve 22 , a second motor mount 24 , a first fastener 23 and a second fastener 25 . The second motor 21 is used to drive the second rotating sleeve 22 to rotate, and the bottom plate 12 is arranged on the second rotating sleeve 22 . The rotating dial 11 , the bottom plate 12 , the first rotating sleeve 18 and the second rotating sleeve 22 are coaxially arranged, and the first rotating sleeve 18 is sleeved on the outside of the second rotating sleeve 22 .

The second motor mount 24 is fixed on the main body support 51 of the extrusion device, and the second motor 21 is fixed on the second motor mount 24 . In this embodiment, the first motor mount 19 is fixedly connected to the second rotating sleeve 22 through the first fastener 23 , so that the variable-diameter spray head can rotate synchronously with the second rotating sleeve 22 . In other embodiments (not shown), the arrangement of the first motor mount 19 on the second rotating sleeve 22 may also be integrally formed. The second motor 21 is connected with a rotating shaft to form a rotating module, and the structure of the rotating shaft is the same as the installation method and the first rotating sleeve 18 of the reducing nozzle. The second rotating sleeve 22 is rigidly connected to the rotating shaft in the rotating module through the second fastener 25. When the second motor 21 receives the rotation signal and rotates, the second rotating sleeve 22 is fixed on the second fastener 25. Driven by the synchronous rotation. In other embodiments (not shown), the second motor 21 and the second rotating sleeve 22 may also be directly connected using structures such as a reducer and a sprocket.

Please refer to FIG. 10 , the stirring module 3 is composed of a third motor 31 , a stirring impeller 32 , a hopper 33 and other components. The stirring module 3 includes a third motor 31 , a sprocket mechanism 35 , a third rotating sleeve 34 , a stirring impeller 32 and a hopper 33 . The third motor 31 is connected to the stirring impeller 32, and the stirring impeller 32 is placed in the hopper 33, and the lower part of the hopper 33 is a material outlet. The third motor 31 is connected to the third rotating sleeve 34 through the sprocket mechanism 35 , the lower end of the third rotating sleeve 34 is fixedly connected to the stirring impeller 32 , and the impeller is located in the hopper 33 . The third motor 31 of the stirring module 3 controls the rotating speed of the stirring impeller 32 within an appropriate range, and keeps the material in the hopper 33 to maintain ideal fluidity through stirring, and cooperates with the conveying module to extrude the material downward.

Please refer to FIG. 11 , the conveying module includes a fourth motor 41 , a coupling 42 , a screw 43 , a stator 44 of a screw pump, and a linkage shaft 45 . The fourth motor 41 is connected to the screw rod 43 through the linkage shaft 45 and the coupling 42, the screw pump stator 44 is installed at the material outlet of the lower part of the hopper 33, and the upper part of the screw rod 43 is located in the screw pump stator 44. The upper part of the second rotating sleeve 22 of the rotating module 2 is provided with a stepped hole for connecting the lower part of the screw pump stator 44 , and the lower part of the screw rod 43 is located in the second rotating sleeve 22 . The third motor 31 is connected with the stirring impeller 32 through the third rotating sleeve 34, the connecting shaft (ie linkage shaft 45) of the fourth motor 41 and the screw rod 43 is coaxially arranged with the third rotation sleeve 34, and the linkage shaft 45 is located at the first Three rotating sleeves 34 inside.

In this embodiment, the stirring impeller 32, screw 43 blade, motor, etc. of the stirring module 3 and the feeding module are all connected by an elastic coupling 42, which has good cushioning and shock absorption, and can be easily disassembled and cleaned at any time. Conducive to equipment maintenance.

Please refer to Figure 12, the extrusion device of the present invention also includes an auxiliary structural member 5, the auxiliary structural member 5 includes a main body bracket 51, a third motor mounting seat 52, a fourth motor mounting seat 53, a hopper mounting seat 54, and a first protective cover 55, the second protective cover 56 and the material inlet. The main body bracket 51 is used to support each module, and install each module together on the gantry type three-axis coordinate machine of the 3D printing system. The third motor mount 52 is used to install the third motor 31, the fourth motor mount 53 is used to install the fourth motor 41, the hopper mount 54 is used to install the hopper 33, and the first protective cover 55 is used to protect the sprocket mechanism 35 , the second protective cover 56 is used to protect the rotating module 2 . In particular, in this embodiment, both the first protective cover 55 and the second protective cover 56 are made of transparent materials, such as acrylic material, so that it is convenient to observe the internal operating conditions and find problems in time.

The assembly relationship between each component of the auxiliary structural member 5 and other modules is shown in Figures 1-3. Since this embodiment adopts a conventional bolt installation and fastening method, it is not repeated here.

Please refer to FIG. 13 , which is a block diagram of the working principle of the present invention. The working process of extrusion device of the present invention is as follows:

(1) The third motor of the stirring module 3 drives the stirring impeller 32 to stir the material supplied by the feeding device in the hopper 33, and matches the reasonable impeller speed according to the consistency of the material to make the material reach the fluidity required for extrusion.

(2) The servo motor of the feeding module 4 drives the screw 43 to rotate through the linkage shaft 45, the coupling 42, etc., and matches the reasonable rotation speed of the screw 43 according to the translational speed of the X and Y axes of the moving device, so as to evenly and stably vertically downward Convey the material in the hopper 33.

(3) The first motor of the variable-diameter nozzle 1 drives the rotary dial 11 to rotate at a certain angle at a certain speed, and drives the right-angle moving piece 15 to perform centrifugal or centripetal sliding along the bottom plate 12, so that several right-angle moving pieces 15 are spliced together. The square nozzle 151 changes its size in real time to control the width of the strip material conveyed downward by the material conveying module 4 to adapt to the geometrical size of the graphics on the current travel route of the square nozzle 151 to achieve efficient and accurate printing.

(4) The servo motor of the rotating module 2 drives the rotating sleeve sleeved outside the stator of the screw rod 43 to rotate at a certain angle at a certain speed in real time according to the current travel path of the square nozzle 151, and to control one side of the square nozzle 151 to always move along the tangential direction of the path , cooperate with variable-diameter nozzle 1 to control the molding appearance quality of graphic components.

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (10)

1. A variable-diameter nozzle for building 3D printing, characterized in that it includes: a rotary dial, a bottom plate, four linear guide rails, four sliders and four right-angle moving pieces; There are four drive slots on the circumference of the rotary dial; The bottom plate is located under the rotary dial; four linear guide rails are distributed in a square and installed on the bottom plate; The four sliders are slidably installed on the four linear guide rails one by one, and each of the four sliders is provided with a driving part, a total of four driving parts, which are inserted into the four driving grooves in one-to-one correspondence; The four right-angled moving pieces are located under the bottom plate, and are installed on the four sliders one by one, and the right-angled sides of the four right-angled moving pieces are attached in pairs to form a square nozzle in the middle; among them, The geometric center of the square nozzle is located on its rotation axis; Both the bottom plate and the rotary dial are provided with through holes corresponding to the square nozzles for feeding; When the rotary dial and the bottom plate rotate relative to each other, the rotary dial drives the four driving parts to rotate synchronously through the four driving grooves, and then drives the four sliders to slide synchronously along the four linear guide rails, and the four sliders drive the four right-angled moving parts. The relative movement of the slices synchronously changes the caliber of the square nozzle. 2. A variable-diameter nozzle for building 3D printing as claimed in claim 1, characterized in that it includes a limiting plate; the limiting plate has a plane, which is close to four right-angle moving pieces to ensure four The two right-angle moving pieces are always on the same plane during the movement; the limiting plate is provided with through holes corresponding to the square nozzles. 3. A variable-diameter nozzle for building 3D printing as claimed in claim 1 or 2, characterized in that it comprises four bearings, which are arranged in four drive slots in one-to-one correspondence; the four drive parts are shafts Shaped structure, one by one inserted into the four bearings. 4. An extrusion device for architectural 3D printing, characterized in that it comprises the variable-diameter nozzle according to any one of claims 1-3. 5. A kind of extrusion device for building 3D printing as claimed in claim 4, it is characterized in that, variable-diameter nozzle comprises a first rotating sleeve and a first motor, and the first motor is used to drive the first rotating sleeve Rotation; the rotary dial is set on the first rotary sleeve and rotates synchronously with the first rotary sleeve. 6. A kind of extrusion device for building 3D printing as claimed in claim 5, is characterized in that, comprises rotating module, and this rotating module comprises second rotating sleeve and second motor; The second motor is used for driving the first The second rotating sleeve rotates, and the bottom plate is arranged on the second rotating sleeve; The rotating dial, the bottom plate, the first rotating sleeve and the second rotating sleeve are coaxially arranged, and the first rotating sleeve is sleeved on the outside of the second rotating sleeve. 7. A kind of extrusion device for building 3D printing as claimed in claim 5 or 6, is characterized in that, comprises stirring module and material delivery module; Stirring module, material delivery module, rotary module and variable diameter spray nozzle Arranged sequentially from bottom to top; The stirring module includes a third motor, a stirring impeller and a hopper; the third motor is connected to the stirring impeller, the stirring impeller is placed in the hopper, and the lower part of the hopper is the material outlet; The feeding module includes a fourth motor, a screw, and a screw pump stator; the fourth motor is connected to the screw, the screw pump is installed at the material outlet of the lower part of the hopper, and the upper part of the screw is located in the screw pump; The upper end of the second rotating sleeve of the rotating module is connected with the screw pump, and the lower part of the screw is located in the second rotating sleeve. 8. A kind of extrusion device for building 3D printing as claimed in claim 7, it is characterized in that, the third motor and the stirring impeller are connected through the third rotating sleeve, the connecting shaft of the fourth motor and the screw is connected with the third The rotating sleeve is coaxially arranged and located inside the third rotating sleeve. 9. An extrusion device for building 3D printing as claimed in claim 7, wherein the rotating module further comprises a first motor mounting base, and the first motor mounting base is fixed outside the second rotating sleeve; A motor and the first rotating sleeve are installed on the first motor mounting base and move synchronously with the second rotating sleeve; the first rotating sleeve can rotate relative to the first motor mounting base. 10. An extrusion device for building 3D printing according to claim 7, characterized in that the limiting plate is installed on the first motor mounting base and moves synchronously with the first motor mounting base, and the bottom plate is positioned at the limiting position. between the plate and the first motor mount.

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