Polishing machine for 3D printing substrate

The invention is suitable for the field of 3D printing, and provides a polishing machine for a 3D printing substrate, the polishing machine comprises a bottom plate, four guide columns are fixedly connected to the top of the bottom plate, a mounting table is fixedly connected among the four guide columns, a mounting frame is slidably connected among the four guide columns, and the mounting frame is located above the mounting table. The device further comprises four bearing assemblies, the four bearing assemblies are all installed at the bottom of the installation frame, and the bearing assemblies are used for containing a base plate. By arranging a piston cylinder, a piston plate, a piston rod and a soot blowing pipe, the mounting frame can drive the base plate to slowly fall at a constant speed, meanwhile, the soot blowing pipe blows soot on the surface of the polishing disc and blows off ground residues, the surface of the base plate is prevented from being damaged, the smoothness of the surface of the base