A cement-based material 3D printing nozzle with a self-constraining device

Abstract

The invention discloses a three-dimensional (3D) printing spray head with a self-restraint device for cement-based materials. The spray head comprises a hopper (1), a nozzle (2) connected with the lower part of the hopper (1), a rectangular connecting plate (3) arranged under the nozzle (2), and the self-restraint device arranged under the rectangular connecting plate (3) from top to bottom. The self-restraint device comprises an upper restraint plate (4), a left-side restraint plate (5) and a right-side restraint plate (7) distributed on two sides of the restraint plate (4), and a cutting groove (6) located on the lower surface of the upper restraint plate (4); the upper restraint plate (4) is fixedly connected with the rectangular connecting plate (3); and holes with the size same as thesize of the nozzle (2) are formed at the positions, corresponding to the nozzle (2), on the rectangular connecting plate (3) and the upper restraint plate (4). According to the spray head, the problems of cavities and cold joints existed in 3D printed cement-based material components can be solved, and meanwhile, the surface smoothness of a printed finished product can be improved.

Description

technical field [0001] The invention relates to a cement-based material 3D printing nozzle with a self-constraining device, belonging to the technical field of 3D printing. Background technique [0002] 3D printing, also known as additive manufacturing, originated in the 1980s. It refers to the continuous physical layer superposition, through the three-dimensional model of plastic, metal powder or inorganic non-metallic powder and other bondable materials by layer-by-layer method. A technique for generating three-dimensional solids. 3D printing integrates cutting-edge technical knowledge in many aspects such as digital modeling technology, electromechanical control technology, information technology, material science and chemistry, and has a high technological content. [0003] Concrete is the largest and most widely used building material in construction. 3D printing building materials are 3D printing concrete technology. It is a new technology developed on the basis of 3D...

AI Technical Summary

Problems solved by technology

The traditional construction industry requires a lot of labor, and the concrete grouting process consumes a lot of energy and materials, which is inefficient and dangerous during the construction process. However, the use of 3D printing technology can save 35%-60% of concrete consumption, and both There are advantages of self-compacting concrete without tamping, and sprayed concrete is convenient for manufacturing complex components. Therefore, 3D printing of building materials is an important direction for the transformation and development of the construction industry in the future.

[0004] The 3D printing of cement-based materials is different from metal materials or resin materials, and cannot be fused together at high temperature or in a molten state, so there will be cold seams between each layer of printing, which makes the bonding force between layers worse, and the wall Higher compressive strength but lower shear strength

During the printing process, since the material is piled up layer by layer, the part printed first must bear the weight of the piled up part printed later. Therefore, the material needs to have a short initial setting time and strong initial setting strength. After sufficient strength, the cement-based material is exposed to the air for too long, which will lead to a decrease in the bonding strength of the upper and lower layers

Due to its own gravity, the printed strip will collapse into an oval-shaped waist drum, which will cause corrugated protrusions on the surface of the printed product, which will greatly affect the surface finish and overall strength. produce cavities

[0005] To sum up, the inevitable cold seams and cavities in 3D printing cement-based materials will greatly affect the strength of the overall component. Therefore, how to solve the problems of cold seams and cavities is what those skilled in the art need to solve. technical issues

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