During the curing process of EPS automatic air cooling block molding machine, beads are cooled by air, and the foaming agent and water vapor in the beads pores condense into liquid, thus forming a vacuum environment. At the same time, the air penetrates into the beads through, so that the pressure inside is balanced with the external pressure. This will make the pre expanded bead elastic. During aging and storage, the foaming agent also diffuses outward at the same time, so the quality guarantee period of beads after pre expansion won't be too long.

The block molding machine working consists of two stages, steam heating and cooling. The pre expanded beads after aging are heated by steam. In a period of about 10 to 50 seconds, the air will not flow out and pressure will be generated after expansion. At this time, the sum of the softening of the polymer, the pressure generated by the evaporation of the foaming agent and the pressure generated by the air is greater than the external steam pressure, and the beads pre expand again and expand into bead gaps to form a whole, forming EPS block in the machine, which are cooled with air.