APPARATUS AND METHOD FOR MOULDING AN OPENING DEVICE ON A PACKAGING SHEET

摘要

An apparatus and method for moulding opening devices (16) onto a packaging material sheet (4) at respective holes (32) provided in the sheet. The apparatus includes first and second mould tools (20, 22) arrangeable in a closed position so as to be in contact with opposite sides (24, 26) of the sheet and in an open position so as to be positioned distally from the sheet. In the closed positions a mould cavity (28) is formed between the first and second mould tools for accommodating a hole edge (30) in the sheet. The apparatus further includes an injection passage (36) for injecting heated thermoplastics material into the mould cavity, which injection passage extends in one of the mould tools such that the thermoplastics material is injected directly into the mould cavity at an injection point (38) of the mould cavity which is located distally from the hole edge, for providing effective formation of the opening device on the sheet. One of the mould tools includes a pair of half mould tools (22a, 22b) which are simultaneously moved from the open position to the closed position and vice versa such that the direction of movement of each of said half mould tools between the open and closed positions tangentially follows a circular path, for reducing wear of the mould tools. In the closed position of the mould tools, the sheet extends in a plane which is distally spaced from the plane of extension of the sheet in the open position aiding in release of the sheet and the moulded opening device from the mould tools.