Patent ID: 6203751
Filing Date: 2001-03-20
Classification: B29C,B29K

Abstract:
Method for forming open containers from a flat thermoformable sheeting (4) consisting of foam material or containing at least one layer of such material with the help of a cooperating pair of a female tool (2) with a recess and a male tool (1) movable into the recess of the female tool (2) thereby drawing the flat sheeting (4) positioned over the opening of the recess and having an elevated temperature above its plastication temperature, wherein during the movement of the male tool (1) towards the female tool (2) and to its end position in the recess of the female tool thereby contacting and drawing the sheeting, the pressure on at least one side of the sheeting is reduced such that it reaches a value below ambient pressure which is low enough for expanding the foam material when the male tool (1) is reaching or has just reached its end position and that the reduced pressure is maintained until the sheeting temperature is below the plastication temperature of the foam material, characterized in that the sheeting positioned over the recess of the female tool is prestretched into the recess with the help of a pressure difference between the male tool side of the sheeting and the female tool side, such that the face of the moving male tool (1) contacts the sheeting inside the recess.