Processes and apparatuses for perforating smooth, closed-cell surfaces of open-cell plastic foam sheets

An apparatus for perforating one or more smooth, closed surfaces of open-cell plastic foam sheet comprising:

• a fixed mold block adapted for molding the side walls and the bottom of a tray or a container from a plastic foam sheet, wherein the fixed mold block comprises
• a fixed base plate with mutually parallel channels disposed in the base plate and lying one above the other and adapted for transporting a cooling medium, vacuum and pressure medium, and
• a male mold having needle pistons, and
• needles having needle tips arranged on the needle pistons, wherein during a perforation operation the needles with needle tips extend perpendicularly from their positions within the male mold onto the side walls and the bottom lying opposite the surface of the male mold.

An apparatus for perforating one or more smooth, closed surfaces of open-cell plastic foam sheet comprising:

• a base frame with vertical guide rods;
• a pressure plate mounted in a fixed position on the guide rods;
• a mounting plate displaceably arranged along the guide rods;
• and
• a mold block disposed on the mounting plate, wherein said mold block comprises
• a base plate;
• and
• one or more perforating blocks containing movable or fixed needles arranged in a matrix arrangement, wherein the one or more perforating blocks are adapted such that during a perforating operation the needles with needle tips project from the surface of the one or more perforating blocks to such an extent that they pierce a surface skin of the plastic foam sheet.

An apparatus for perforating one or more smooth, closed surfaces of open-cell plastic foam sheets, wherein the apparatus comprises:

• a mold block which comprises:
• a cooling plate;
• a mounting plate;
• a male mold having a top wall and sidewalls;
• and
• fixed needles anchored in the top wall and sidewalls of the male mold, wherein the tips of the fixed needles project outward from the male mold, wherein the mold block is disposed in a thermoforming unit, and wherein the mold block is adapted such that during a perforation operation the needles with the needle tips project from a surface of the male mold to such an extent that the pierce a surface skin of the plastic foam sheet.