Tunneling machines are called“Underground dragon”，The cutterhead is like steel teeth.，Into the ground can eat soil.，Rubble stone in case of mountain，However, after high-intensity construction operations,，Worn tools need to be replaced。At present, there are two main techniques for changing the cutter head of tunnel boring machine.：Manual tool change and robot tool change。Manual tool change means that the operator directly enters the cutter head area to change the tool.，Including conventional manual tool Chan、There are three ways to change tools by freezing method and normal pressure.。Robot tool change refers to the use of fully intelligent robots to detect tools.、Cleaning、Disassembly, assembly, replacement and other tool changing technologies。

At present, the cutter head of most tunnel boring machines still adopts the technology of manual cutter replacement.，Among them, the cutter head of some super-large diameter slurry balance shield machines adopts the technology of changing cutters under normal pressure.，The operator can change the cutter under the normal pressure inside the cutter head.，And that safety is greatly improve.。Robot tool changing is currently in the scientific research stage in the industry.，The technology is not yet widely available。

China Railway Construction Heavy Industry Co., Ltd. has been engaged in the Haizhuwan Tunnel Project in Guangzhou、Changde yuanjiang River-crossing Tunnel Project、Successful application of atmospheric pressure tool change in many projects such as Beijing East Sixth Ring Road Reconstruction Project，The freezing method is mainly used in Guangzhou Metro 18./Line 22, the world's largest 52 shield machine construction fleet。