Method and apparatus for producing open containers from foam sheeting

Abstract

The inventive method serves for producing open containers from a flat sheeting (,) consisting of a foam material or containing at least one layer of such a material, by drawing the sheeting with the help of a female (,) and a male tool (,) and by expanding the foam material with the help of a pressure reduction. The action sequence of one cycle of the inventive method is e.g. the following: positioning and clamping the sheeting (,) over the opening of the recess in the female tool (,); moving the male tool (,) into the recess and at the same time prestretching the sheeting with the help of a pressure difference between its two sides, such that the face of the male tool (,) gets in contact with the prestretched sheeting inside the recess; drawing the sheeting further by moving the male tool (,) to its end position in the recess of the female tool (,) and at the same time reducing the pressure on the female tool side or on both sides of the sheeting such that it reaches a value below ambient pressure which is sufficiently low for expanding the foam material and keeping the reduced pressure until the sheeting is cooled below plastication temperature; then equalizing the pressure and demolding and declamping the formed container and advancing the sheeting for a further method cycle.