Preparation method of 3D printing-based YBCO superconducting twisted wire

A 3D printing-based preparation method of YBCO superconducting twisted wire, wherein, comprising following steps:

• 1) Preparing a superconducting powder precursor:
• taking YBCO superconducting material or mixed powder being sintered for forming a superconducting phase as a main printing material;
• obtaining printing powders with particle diameters of 100-300 nm by crushing mechanically the main printing material;
• 2) Preparing a printing paste:
• adding the superconducting powder precursor, which has been ground, to a mixture of polymer binder and lubricant to form a direct ink writing 3D-printing paste;
• 3) Printing a twisted wire by a direct ink writing 3D printer;
• importing slice data of a processed model into a numerical control terminal of a computer, a digital signal being transmitted to a communication board by a computer, simultaneously the communication board sending an ink-supplying communication command and a print-driving command;
• after sending the ink-supplying communication command, an electromagnetically controlled gas valve is opened, a pneumatic pressure is loaded to a pushing plug in a hopper, then the pressure is transmitted to the printing paste for forming a uniform and smooth printing line;
• after sending the print-driving command, controllable drivings in X-Y-Z triaxial directions are separately implemented by three servo motors, wherein a precise location of printing needles in an X-Y plane are provided by moving on X and Y axes, and an up-down movement of a bottom platform is provided by transmission via a roller screw on a Z axis;
• at the same time, the print-driving command is also sent to the servo motors which bring a rotation of the printing needles;
• thereby three filaments extruded from the printing needles are fixed on a Z-axis platform and are twisted together in the X-Y plane under continuous rotations of assembly of the printing needles;
• synchronously, in co-operation with an extension of the filaments, the rotation of the printing needles and the downwards movement of the bottom platform, the twisted wire is prepared by continuously extending the filaments through the printing needles in the Z-axis direction and moving synchronously the platform down;
• the twisted wire with the required parameters is prepared by adjustments of diameter of the printing needles, extrusion pressure, falling speed of the bottom platform and rotation speed;
• 4) Plastic removing and superconducting crystallizing;
• 5) Assembling process.