A memory device may include a plurality of memory cell transistors serially coupled in a string between a string selection transistor and a ground selection transistor. At least one recess is made in the sheet and extends through the insulating-material layer as far as the conductive layer on the opposite surface. In a first embodiment, the pivot point is located in the center of the rotating assembly equidistant from the two or more sides, along a substantially vertical axis. The support member is slidably supported, received and retained on the first part. A guide, which extends the opening stroke of the mold core, is formed at a distance from the parting plane, between the slider and at least the mold core, the guide preferably comprising second, lateral projections and second guide grooves.