Tool clamping mechanism for plastics injection molding machine has magnets around tool cavity in one tool half and magnetic second tool half which is attracted towards first tool half by magnetic force

摘要

One of more first magnets(7,8) are integrated in the first tool half(3) of a two or more part tool(2) which encloses a molding cavity(5). The second tool half(4) is made at least partly from a magnetic material and magnetic force produced by magnets in the first tool half holds the tool halves together in the closed position. The first magnets(7,8) may comprise electromagnets with an electrical coil. The strength of current (I1,I2) flowing through the coil can be varied as can its flow orientation and the current can also be switched on and off. Alternatively the first magnets can be permanent magnets. In a variation of the clamping mechanism a first magnet(7) is used in conjunction with at least one further magnet and at least one of the magnets is an electromagnet with variable magnetic properties. Magnets may be arranged close to each other to form pairs. Additional electromagnets may be arranged in the second tool half. At least one magnet is located above the molding cavity and at least one other magnet below the cavity to create a magnetic field(B1) which completely surrounds the cavity. An electric drive unit(9), preferably a linear motor, opens and closes at least one(3) of the tool halves.