3D printing system, forming process and application

The invention provides a 3D printing system. The 3D printing system comprises a printing module, a clamping module, a movement module and a control module. And a printing head of the printing module is provided with an extrusion part which is used for extruding the slurry extruded from the end part of the discharging channel so as to compress the slurry. According to the forming process, accurate control over the width and the height of the component unit is achieved by controlling the feeding pressure, the printing speed and the height of the extrusion part. Through the arrangement of the extrusion part, the height and the width of the component unit can be accurately controlled in cooperation with a forming process, and the precision of 0.001 mm is achieved. Through stacking of component units, direct writing and printing of high-precision components, especially ultra-thin-wall structures, can be achieved, and the high-precision component is suitable for products such as precision radiators, optical grating