Device and casting method thereof for elongated spiral holes through lost foam casting

The invention relates to a device and a method for casting, particularly to the device and a casting method thereof for elongated spiral holes through lost foam casting. The device comprises a sand box for casting, and a plurality of branch negative pressure pipes, a main negative pressure pipe and an exhaust pipe which are arranged in the sand box. The plurality of branch negative pressure pipes are communicated with the main negative pressure pipe respectively, holes are dilled on the branch negative pressure pipes respectively, the exhaust pipe is communicated with the main negative pressure pipe, a central negative pressure pipe is arranged in the middle of the sand box, a central negative pressure hole is drilled on the central negative pressure pipe, the surface of the central negative pressure pipe is coated by screens, one end of the central negative pressure pipe is connected with the branch negative pressure pipes in the middle of the sand box, and the other end is sealed; and straight negative pressure pipes are arranged at four corners inside the sand box respectively, two of the straight negative pressure pipes are connected with the branch negative pressure pipes on the outer side of the sand box respectively, the other two straight negative pressure pipes are connected with the main negative pressure pipe respectively, and straight negative pressure pipe holes are drilled on the surfaces of the straight negative pressure pipes. The device is simple in structure, convenient to operate, effectively solves the technical problem of the elongated spiral holes through lost foam casting, and greatly reduces the rejection rate of castings.