The main productive process problem of the metal culvert pipe
include the pleat and pumping material. Because the slow speed of the pushing and fast release speed, the pressure inner the canister is lower than the briquetting pressure. Then the metal culvert pipe
can be pressed down and form the pleats. The pumping material means the fast speed of the pushing and slow release speed, so the pressure inner the tube is higher than the forming pressure, which is easy to form the waste. The solutions to those problems are adjust the speed of the pushing and release, keep the required forming pressure.