Suitable for transparent, high viscosity, easy to crack, high molecular weight plastic with filter device characteristics; modular leak-proof steel sleeve, which can be disassembled and worn by itself without further processing; the flow channel does not retain plastic, and the residence time is short; The processing temperature adjusts the material's expansion coefficient on the spot to prevent leakage. The oil pressure start-up time of the hole-to-hole screen change is about 0.01 seconds, and the production is not interrupted. The steel mold of the filter hole can be removed separately to ensure that the plastic in the retention hole is cleaned and replaced quickly Steel mold with filter holes to ensure that the plastic behind the filter is clean; there is a preheating device that does not slow down the cooling and flow of the plastic when changing the screen.