METHOD OF PNEUMO-VACUUM MOLDING OF ITEMS OUT OF SHEET OR FILM TYPE THERMOPLASTICS Russian patent published in 2004 - IPC

FIELD: chemical and a food-processing industry. SUBSTANCE: the invention presents a method of pneumo-vacuum molding of items out of sheet or film type thermoplastics and is dealt with the methods of processing of plastics materials, namely with methods of pneumo-vacuum molding of items out of sheet or film thermoplastics and may be used in chemical and food- processing industry at manufacturing of containers, for example, standard packs. The method provides for installation of a sheet or film type slug of a thermoplastic material on a molding die, heating the slug up to molding temperature and its deformation by difference of pressures to put it into the given shape. The die represents a plate with, at least, one cell made as a form-shaping pit with the lateral plungers. The slug is deformed using stretching by a difference of pressures at pushed into the space of a shaping pit of the form-building parts of the plungers up to a contact of the slug with them and with the surface of the shaping pit. Then the molded item is cooled and extracted from the die. Extraction of the item is realized simultaneously with an exit of the shaping parts of the plungers from the space of the shaping pit due to application to the item of such extracting force, that overcomes the resisting strength of the springs, that pushed the shaping parts of the plungers into the shaping pit of the die. For this purpose the shaping parts of plungers are made beveled or rounded on the side of the corresponding protruding parts of the item shaped by them. The invention allows to simplify a method of molding of items. EFFECT: the invention allows to simplify the method of the items molding. 4 dwg