During the curing process of the EPS automatic air-cooling block molding machine, the beads are cooled by air, and the foaming agent and water vapor in the pores of the cells are condensed into a liquid, so that a vacuum is formed in the cells. At the same time, air permeates into the interior of the cell through the cell membrane, so that the pressure in the cell is balanced with the external pressure. This will make the beads after the pre-expansion elastic. During the ripening storage process, the foaming agent also diffuses outward at the same time, so the shelf life of the beads after the pre-expansion cannot be too long.
The plastic sheet forming machine includes two stages, steam heating and cooling setting. The pre-cured beads after aging are heated by steam. During the period of about 10 to 50 s, the air does not come out, and after the expansion, the pressure is generated. At this time, the softening of the polymer, the pressure generated by the vaporization of the blowing agent and The sum of the pressures generated by the air in the cells is greater than the external steam pressure, the beads re-expand and expand into the bead gap to form a monolith, forming an EPS foam molded product of the same shape as the mold, cooled by water or air. It can be shaped and finished.