Polishing method for inner wall of hollow metal part

A polishing method for an inner wall of a hollow metal part, wherein comprising three steps in total:

• designing and printing, sealing and polishing as well as reversing and breaking:
• (1) designing and printing:
• adding a coaxial cathode model in an inner hole of a metal part model when designing the metal part model, the coaxial cathode model is corresponding to the inner hole in shape and size and provided with 1-3 breakable structures in the middle part thereof, wherein the breakable structures form breaking points;
• and printing a metal part and a coaxial cathode together by using a 3D printer to complete the designing of the metal part model and the coaxial cathode model and the printing of the metal part and the coaxial cathode;
• (2) sealing and polishing:
• sealing two ends of the inner hole of the metal part by using a light curing sealing ring adapted to the inner hole of the metal part in shape, fixing the coaxial cathode, introducing a polishing solution into the sealed inner hole serving as an electrochemical polishing tank, taking the coaxial cathode as a cathode and the metal part as an anode, and performing electrochemical polishing on an inner surface of the metal part;
• and
• (3) reversing and breaking:
• reversing the electrodes, taking the coaxial cathode as the anode and the metal part as the cathode, fusing the breakable structures of the coaxial cathode to break the coaxial cathode, removing the light curing sealing ring, discharging the polishing solution,
• and taking the broken coaxial cathode out of the inner hole of the metal part to complete reversing and breaking, and realizing the polishing of the inner surface of the metal part.