Forming machine for insulating pipes

The invention discloses a forming machine for insulating pipes. The forming machine is used for manufacturing insulating pipes and the production process is simple. The forming machine for insulating pipes comprises a casing provided with a cavity, wherein the cavity is provided with a feeding port and a discharging port, and a truncated cone segment and a cylinder segment are formed in a position, between the feeding port and the discharging port, of the cavity, and adjoin to each other; besides, the cylinder segment is away from the feeding port relative to the truncated cone segment; a screw is arranged on the casing rotatably, and arranged on the truncated cone segment and the cylinder segment in a penetrating manner; a cavity is formed between the outer surface of the screw and the inner surface of the casing, and a spiral groove in the screw extends to the truncated cone segment from the lower position of the feeding port.