Epp foam box mold locking device. The complete liquid reaction injection system consists of four locking devices, and the four decomposition actions in one cycle are as follows:
　　① The locking mechanism fixes two half molds together and rotates 90 ° to release air through the parting surface. Then turn to the operator, take out the parts, and provide space for cleaning and removing the mold.
　　② After turning the upper and lower molds to a parallel position, prepare to close the mold.
　　③ The long stroke hydraulic cylinder rises, and the lower and upper templates are closed and locked together. A constant clamping force can ensure a uniform and tight fit of the parting surface.
　　④ The entire C-shaped frame rotates in a certain direction to exhaust the air inside the mold cavity. After the material is filled, the C-shaped frame returns to the upper right position to fully solidify the workpiece
　　The lower half of the mold descends, and the template turns to the predetermined position in order to remove the part and prepare to enter the next cycle.
　　The RIM injection machine should have the following functions.
　　1) There is appropriate locking force to ensure a tight closure of the parting surface;
　　2) Efficient structure for installing two half molds;
　　3) The mold can be rotated 90 ° for feeding and effective exhaust can be carried out. After filling the mold, it should be restored to a horizontal position for solidification;
　　4) After solidification, the injection machine should quickly open the mold and rotate the two half molds to the "predetermined" position for quick removal of the parts, then clean the burrs or adhesive on the mold, and apply the release agent.
　　Mold design is also one of the key factors in RIM molding. The basic elements of the reaction injection mold for the epp foam box are similar to those of the injection mold, that is, it is composed of a core and a cavity. However, because the injection pressure required for reaction injection is much smaller than that for injection molding, the structure can be greatly simplified.