Abstract: The disclosure belongs to the technical field of additive manufacturing, and discloses a flexible piezoelectric sensor based on 4D printing and a preparation method thereof. The sensor includes a magnetic part and a conductive part, wherein: the conductive part includes two substrates disposed opposite to each other and a spiral structure disposed between the two substrates. Both the two substrates and the spiral structure are made of conductive metal materials. The magnetic part has a flexible porous structure and is arranged between the two substrates to generate a magnetic field. When the substrate is subjected to external pressure, the spiral structure and the magnetic part are compressed simultaneously, the magnetic flux passing through the spiral structure changes, and the voltage of the two substrates changes, by measuring the voltage change of the two substrates to reflect the change of external pressure, the pressure measuring process is achieved.

Abstract: The present invention provides composites with controllable superhydrophilic and superhydrophobic performances, a 3D printing method and 3D printed parts. The composites with controllable superhydrophilic and superhydrophobic interface performances comprise hydrophobic powder and/or hydrophilic powder and jointing phase powder, wherein the jointing phase powder is thermoplastic polymers. The present invention can print the parts with a continuous wettability change from superhydrophilic to superhydrophobic performances by regulating the mass percentage of the hydrophobic powder, the hydrophilic powder and the jointing phase powder. Furthermore, the present invention can prepare the models with various shapes according to different application scenes, and regulate the interface wettability performances of the models.

Abstract: The present invention provides composites with controllable superhydrophilic and superhydrophobic performances, a 3D printing method and 3D printed parts. The composites with controllable superhydrophilic and superhydrophobic interface performances comprise hydrophobic powder and/or hydrophilic powder and jointing phase powder, wherein the jointing phase powder is thermoplastic polymers. The present invention can print the parts with a continuous wettability change from superhydrophilic to superhydrophobic performances by regulating the mass percentage of the hydrophobic powder, the hydrophilic powder and the jointing phase powder. Furthermore, the present invention can prepare the models with various shapes according to different application scenes, and regulate the interface wettability performances of the models.

Abstract: A selective laser sintering (SLS) device. The SLS device includes a laser forming unit, a support platform and a driving mechanism. The support platform is configured to support a plurality of raw materials for additive manufacturing of an object including a plurality of sections. The laser forming unit is disposed on the support platform and is configured to lay powders on a surface of each section of the object and sinter the powders. The driving mechanism is disposed under the laser forming unit and includes a vertical driving mechanism and a horizontal driving mechanism. The vertical driving mechanism is connected to the laser forming unit and configured to lift the laser forming unit layer by layer. The horizontal driving mechanism is configured to drive the laser forming unit to move in a horizontal direction with respect to the support platform.

Abstract: The disclosure belongs to the technical field of additive manufacturing, and discloses a flexible piezoelectric sensor based on 4D printing and a preparation method thereof. The sensor includes a magnetic part and a conductive part, wherein: the conductive part includes two substrates disposed opposite to each other and a spiral structure disposed between the two substrates. Both the two substrates and the spiral structure are made of conductive metal materials. The magnetic part has a flexible porous structure and is arranged between the two substrates to generate a magnetic field. When the substrate is subjected to external pressure, the spiral structure and the magnetic part are compressed simultaneously, the magnetic flux passing through the spiral structure changes, and the voltage of the two substrates changes, by measuring the voltage change of the two substrates to reflect the change of external pressure, the pressure measuring process is achieved.

Abstract: The invention belongs to the field of filament additive manufacturing, and discloses a polymer multi-material high-flexibility laser additive manufacturing system and a method thereof. The system comprises a first robot arm, a second robot arm, a positioner, a rotational extrusion nozzle in which a plurality of extrusion modules are disposed and a laser, each extrusion module is used for extruding one kind of filament, and the rotational extrusion nozzle is connected with the first robot which drives the rotational extrusion nozzle to move according to a preset trajectory; the laser is connected with the second robot, and is used for emitting a laser to fuse the filament extruded from the rotational extrusion nozzle, and through the cooperative motion of the first robot and the second robot, the extrusion and fusion of the filament are performed synchronously; the positioner serves as a forming mesa, and the rotation of the positioner cooperates with the motions of the two robots.

Abstract: A method of preparing a C/C-SiC composite part, including: preparing, using a solvent evaporation process, carbon fiber composite powders coated with a phenol resin; according to a three-dimensional model of a to-be-prepared part, forming a green part corresponding to the to-be-prepared part using the carbon fiber composite powders and a 3D printing technology; densifying the green part to yield a C/C porous body having a density of 0.7 to 1.1 g/cm3 and an open porosity of 30 to 50%; and siliconizing the C/C porous body under vacuum, removing excess silicon to yield a primary carbon fiber reinforced carbon-silicon carbide (C/C-SiC) body, densifying the primary C/C-SiC body, to obtain a final C/C-SiC composite part.

Abstract: A selective laser sintering (SLS) device. The SLS device includes a laser forming unit, a support platform and a driving mechanism. The support platform is configured to support a plurality of raw materials for additive manufacturing of an object including a plurality of sections. The laser forming unit is disposed on the support platform and is configured to lay powders on a surface of each section of the object and sinter the powders. The driving mechanism is disposed under the laser forming unit and includes a vertical driving mechanism and a horizontal driving mechanism. The vertical driving mechanism is connected to the laser forming unit and configured to lift the laser forming unit layer by layer. The horizontal driving mechanism is configured to drive the laser forming unit to move in a horizontal direction with respect to the support platform.

Abstract: The present disclosure belongs to the technical field of advanced manufacturing auxiliary equipment, and discloses an independently temperature-controlled high-temperature selective laser sintering frame structure, comprising a galvanometric laser scanning system, a powder feeding chamber, a forming chamber and a heat-insulating composite plate, and targeted optimization design is performed on the respective functional components.

Abstract: A method for manufacturing a composite product, including: 1) preparing a composite powder including 10-50 v. % of a polymer adhesive and 50-90 v. % of a chopped fiber; 2) shaping the composite powder by using a selective laser sintering technology to yield a preform including pores; 3) preparing a liquid thermosetting resin precursor, immersing the preform into the liquid thermosetting resin precursor, allowing a liquid thermosetting resin of the liquid thermosetting resin precursor to infiltrate into the pores of the preform, and exposing the upper end of the preform out of the liquid surface of the liquid thermosetting resin precursor to discharge gas out of the pores of the preform; 4) collecting the preform from the liquid thermosetting resin precursor and curing the preform; and 5) polishing the preform obtained in 4) to yield a composite product.

Abstract: The present disclosure belongs to the technical field of advanced manufacturing auxiliary equipment, and discloses an independently temperature-controlled high-temperature selective laser sintering frame structure, comprising a galvanometric laser scanning system, a powder feeding chamber, a forming chamber and a heat-insulating composite plate, and targeted optimization design is performed on the respective functional components.

Abstract: The invention belongs to the field of filament additive manufacturing, and discloses a polymer multi-material high-flexibility laser additive manufacturing system and a method thereof. The system comprises a first robot arm, a second robot arm, a positioner, a rotational extrusion nozzle in which a plurality of extrusion modules are disposed and a laser, each extrusion module is used for extruding one kind of filament, and the rotational extrusion nozzle is connected with the first robot which drives the rotational extrusion nozzle to move according to a preset trajectory; the laser is connected with the second robot, and is used for emitting a laser to fuse the filament extruded from the rotational extrusion nozzle, and through the cooperative motion of the first robot and the second robot, the extrusion and fusion of the filament are performed synchronously; the positioner serves as a forming mesa, and the rotation of the positioner cooperates with the motions of the two robots.

Abstract: A method of preparing a C/C-SiC composite part, including: preparing, using a solvent evaporation process, carbon fiber composite powders coated with a phenol resin; according to a three-dimensional model of a to-be-prepared part, forming a green part corresponding to the to-be-prepared part using the carbon fiber composite powders and a 3D printing technology; densifying the green part to yield a C/C porous body having a density of 0.7 to 1.1 g/cm3 and an open porosity of 30 to 50%; and siliconizing the C/C porous body under vacuum, removing excess silicon to yield a primary carbon fiber reinforced carbon-silicon carbide (C/C-SiC) body, densifying the primary C/C-SiC body, to obtain a final C/C-SiC composite part.

Abstract: A method for preparing a three-dimensional porous graphene material, including: a) constructing a CAD model corresponding to a required three-dimensional porous structure, and designing an external shape and internal structure parameters of the model; b) based on the CAD model, preparing a three-dimensional porous metal structure using a metal powder as material; c) heating the three-dimensional porous metal structure and preparing a metal template of the required three-dimensional porous structure; d) placing the metal template in a tube furnace and heating the metal template to a temperature of between 800 and 1000° C.; standing for 0.5-1 hr, introducing a carbon source to the tube furnace for continued reaction, cooling resulting products to room temperature to yield a three-dimensional graphene grown on the metal template; and e) preparing a corrosive solution, and immersing the three-dimensional graphene in the corrosive solution.

Abstract: The present invention discloses polyetheretherketone/nano-hydroxyapatite (PEEK/NANO-HA) composites for selective laser sintering (SLS), and a preparation method thereof. The method for preparing the composites comprises steps of: selecting PEEK having a particle size of 10-100 ?m, and an aqueous solution of reaction precursor 1 and an aqueous solution of reaction precursor 2, uniformly dispersing the PEEK in the aqueous solution of reaction precursor 1, adding the aqueous solution of reaction precursor 2 dropwise in the mixed solution of the aqueous solution of reaction precursor 1 and the PEEK while stirring to adjust pH of the mixed solution to 10-12, and continuously reacting or 24-48 hours. The composites obtained by the preparation method of the present invention have the advantages of good biocompatibility, homogeneous morphology and good fluidity, and are advantageous to the powdering and shaping process during SLS.

Abstract: The present invention discloses polyetheretherketone/nano-hydroxyapatite (PEEK/NANO-HA) composites for selective laser sintering (SLS), and a preparation method thereof. The method for preparing the composites comprises steps of: selecting PEEK having a particle size of 10-100 ?m, and an aqueous solution of reaction precursor 1 and an aqueous solution of reaction precursor 2, uniformly dispersing the PEEK in the aqueous solution of reaction precursor 1, adding the aqueous solution of reaction precursor 2 dropwise in the mixed solution of the aqueous solution of reaction precursor 1 and the PEEK while stirring to adjust pH of the mixed solution to 10-12, and continuously reacting or 24-48 hours. The composites obtained by the preparation method of the present invention have the advantages of good biocompatibility, homogeneous morphology and good fluidity, and are advantageous to the powdering and shaping process during SLS.

Abstract: A method for manufacturing a composite product, including: 1) preparing a composite powder including 10-50 v. % of a polymer adhesive and 50-90 v. % of a chopped fiber; 2) shaping the composite powder by using a selective laser sintering technology to yield a preform including pores; 3) preparing a liquid thermosetting resin precursor, immersing the preform into the liquid thermosetting resin precursor, allowing a liquid thermosetting resin of the liquid thermosetting resin precursor to infiltrate into the pores of the preform, and exposing the upper end of the preform out of the liquid surface of the liquid thermosetting resin precursor to discharge gas out of the pores of the preform; 4) collecting the preform from the liquid thermosetting resin precursor and curing the preform; and 5) polishing the preform obtained in 4) to yield a composite product.

Abstract: A method for preparing a three-dimensional porous graphene material, including: a) constructing a CAD model corresponding to a required three-dimensional porous structure, and designing an external shape and internal structure parameters of the model; b) based on the CAD model, preparing a three-dimensional porous metal structure using a metal powder as material; c) heating the three-dimensional porous metal structure and preparing a metal template of the required three-dimensional porous structure; d) placing the metal template in a tube furnace and heating the metal template to a temperature of between 800 and 1000° C.; standing for 0.5-1 hr, introducing a carbon source to the tube furnace for continued reaction, cooling resulting products to room temperature to yield a three-dimensional graphene grown on the metal template; and e) preparing a corrosive solution, and immersing the three-dimensional graphene in the corrosive solution.