Flexible gas protecting device and method for aluminum alloy arc additive

The invention discloses a flexible gas protecting device for aluminum alloy arc additive. The device comprises a gas protecting chamber body, a supporting device and an executing device, wherein the supporting device is used for supporting the gas protecting chamber body; a gas exhaust pipeline is arranged at the upper end of the gas protecting chamber body; the gas protecting chamber body is provided with a detection device, and the detection device is used for detecting one or more of oxygen concentration, humidity and argon concentration in the gas protecting chamber body; a welding gun isarranged at one end, extending into the gas protecting chamber body, of the executing device, and a gas inlet device is arranged on the welding gun and used for inputting air and argon; a flexible sealing cover used for sealing the gas protecting chamber body is arranged at the joint of the executing device and the gas protecting chamber body; the executing device can move for reset travel in a preset direction in the gas