摘要:
A system for injection moulding of large plastics components in a single shot comprises an extruder and an accumulator fed from the extruder. The accumulator leads into the mould (14) via a mould valve (12) operative, when closed, to close the mould cavity substantially at the mould surface and also to close an outlet (20a) from the accumulator. The valve passage of the mould valve is of relatively large cross section, typically several centimetres or more which facilitates injection at relatively low pressures and also facilitates passage of stones and other particulate matter which may be present if the extrudate is composed of post-consumer recycled plastics.
摘要:
A method and apparatus are provided for moulding an article by feeding molten plastics material into a metering cavity (16) , feeding a predetermined quantity of the material from the metering cavity into a mould cavity via a transition passage (26) adjacent the mould cavity and urging the molten plastics material from the transition passage into the mould cavity with a working stroke of a packing piston (24) , until the packing piston closes a port (28) defined between the transition passage and the mould cavity and a leading face (32) of the packing piston forms part of the peripheral wall of the mould. Less than ninety percent of the mould cavity is filled with the molten plastics material when the packing piston starts its working stroke and the packing piston starts its working stroke while molten plastics material is still being fed from the metering cavity.
摘要:
A system for injection moulding of large plastics components in a single shot comprises an extruder and an accumulator fed from the extruder. The accumulator leads into the mould (14) via a mould valve (12) operative, when closed, to close the mould cavity substantially at the mould surface and also to close an outlet (20a) from the accumulator. The valve passage of the mould valve is of relatively large cross section, typically several centimetres or more which facilitates injection at relatively low pressures and also facilitates passage of stones and other particulate matter which may be present if the extrudate is composed of post-consumer recycled plastics.
摘要:
Die Erfindung betrifft eine Plastifizier- und Einspritzeinheit (1) einer Spritzgießmaschine. Um insbesondere kleinste Mengen an Kunststoffschmelze zum Spritzgießen kleiner und kleinster Formteile in prozesstechnisch optimaler Weise in ein Spritzgießwerkzeug einspritzen zu können, umfasst die Einheit einen Schneckenzylinder (2), in dem eine Plastifizierschnecke (3) drehbar und axial verschieblich angeordnet ist, und ein Einspritzelement (4), das ein Kolben-Zylinder-System (5, 6) umfasst, wobei durch eine axiale Bewegung eines Kolbens (5) in einem Zylinder (6) eine dosierte, in einem Abschnitt (7) des Zylinders (6) hinterlegte Menge an Kunststoffschmelze über eine Einspritzdüse (8) in ein Spritzgießwerkzeug ausgetrieben werden kann, wobei ein Fließweg (9) zwischen dem Ende des Schneckenzylinders (2) und dem Abschnitt (7) des Zylinders (6) angeordnet ist und wobei der Fließweg (9) frei von Ventilelementen ist. Des weiteren betrifft die Erfindung ein Verfahren zum Spritzgießen eines Formteils.
摘要:
A method of moulding and a moulding installation is disclosed. The installation comprises a compounder (16), a flow path (26) from the compounder to a vessel (34) in which the mouldable material emerging from the compounder is accumulated, and further flow paths (28) from the vessel (34) to a number of moulders (30) each of which is associated with a mould (32). The moulders take charges of mouldable material on a cyclical basis.
摘要:
A method and apparatus are provided for moulding an article by feeding molten plastics material into a metering cavity (16) , feeding a predetermined quantity of the material from the metering cavity into a mould cavity via a transition passage (26) adjacent the mould cavity and urging the molten plastics material from the transition passage into the mould cavity with a working stroke of a packing piston (24) , until the packing piston closes a port (28) defined between the transition passage and the mould cavity and a leading face (32) of the packing piston forms part of the peripheral wall of the mould. Less than ninety percent of the mould cavity is filled with the molten plastics material when the packing piston starts its working stroke and the packing piston starts its working stroke while molten plastics material is still being fed from the metering cavity.
摘要:
The apparatus disclosed comprises a barrel (12) in which there is a piston (42) on a shaft (36). The shaft (36) can be moved axially and is surrounded by a feed screw (14). There is a shut-off valve (70) in the barrel (12). The feed screw (14) is used to fill a holding cavity (C) between the piston (42) and the valve (70). The valve is then opened and the piston (42) forces the charge from the cavity (C) into the moulding cavity (30). In its forward position, the piston (42) has its front face forming part of the bounding wall of the moulding cavity (30).
摘要:
Moulding apparatus is disclosed which comprises transfer element (12) which has a holding cavity (14) therein for receiving a charge of mouldable material. Mouldable material in particulate or molten form is fed into a heated passage (30) by a feed spiral (40) in a tube (36). A plunger (42) displaces molten mouldable material along the passage (30) and into the holding cavity (14). The transfer element (12) is then displaced to a position in which the holding cavity (14) is aligned with an opening (18) in a backing plate (16). The opening (18) is in communication with a mould cavity (20) having the shape of the article to be produced. A second plunger (46) displaces the charge of molten mouldable material from the holding cavity (14) through the opening (18) and into the mould cavity.
摘要:
A method of moulding and a moulding installation is disclosed. The installation comprises a compounder (16), a flow path (26) from the compounder to a vessel (34) in which the mouldable material emerging from the compounder is accumulated, and further flow paths (28) from the vessel (34) to a number of moulders (30) each of which is associated with a mould (32). The moulders take charges of mouldable material on a cyclical basis.
摘要:
The apparatus (10) disclosed comprises a barrel (12) in which there is a piston (42) on a shaft (36). The shaft can be moved axially and is surrounded by a feed screw (14). There is a shut-off valve (62) in the barrel. The feed screw is used to fill a holding cavity (C) between the piston and the valve. The valve is then opened and the piston forces the charge from the cavity (C) into the moulding cavity (30).