A system is described comprising an actuator with a piston linearly movable and a needle shutter connected to the piston for regulating the injection flow of molten material from a nozzle into a mold. By a supply circuit pressurized fluid is brought to the piston to move it back and forth. A solenoid valve is connected to the supply circuit and configured so that in resting condition it leaves open a fluid drainage path for bringing the shutter to a closing position.

Disclosed herein are novel methods for forming a polymer part including providing an injection molding system with a shut-off nozzle, where the shut-off nozzle includes a main body, a nozzle tip body, a flow path through the main body and the nozzle tip body, a nozzle tip, and a shut-off mechanism. The nozzle tip includes an internal passage and a cooling mechanism. The shut-off mechanism includes a passageway intersecting the flow path at an angle and a pin positioned in the passageway. The method further includes the steps of initiating an injection molding cycle by injecting molten polymer through the shut-off nozzle into a cavity of a mold, actuating the shut-off mechanism to move the pin in the passageway into the intersection of the passageway and flow path, and initiating the cooling mechanism to solidify molten polymer in the nozzle tip to form a solid slug.

A resin intrusion prevention structure for preventing resin intrusion into a heater in a shut-off nozzle, the shut-off nozzle including a nozzle body having an injection flow path, through which resin flows, in an axial direction and a shut-off valve configured to open and block the injection flow path. The resin intrusion prevention structure is provided in a vicinity of a sliding exposed portion, which is exposed to an outer circumferential surface of the nozzle body in a sliding portion, and is configured to prevent the resin leaking from the sliding exposed portion from intruding into the heater provided in the shut-off nozzle.

A method is described for injecting a molten material from a nozzle into a mold during an injection molding process. The molten material is guided towards the nozzle via a tip insert which is provided with an internal central cavity and houses a valve pin translatable to reach one end of the tip insert and there adjust a flow of molten material. The molten material travels the central cavity, deviates for a first time away from said axis to exit the internal central cavity through at least one first channel which takes it into an auxiliary chamber, approaches the nozzle traveling a distance inside the auxiliary chamber, deviates for a second time and re-enters the internal central cavity through at least one second channel, and travels along a final section of internal central cavity to reach the nozzle and proceeds inside the mould.

A component for a nozzle for injecting molten plastic into a molding cavity of a container, in particular of a test tube or a bottle preform, the component comprising a first body in which a shutter can slide along an axis; wherein the first body has a wall which extends about said axis; wherein said wall is provided with a first zone adapted to guide the sliding of the shutter along the axis, and a second zone which delimits a first stretch of a channel for the molten plastic; wherein said first body is provided with at least one through hole which crosses said wall, in particular transversely to the axis, which allows the molten plastic to pass through, in particular to enter, said first stretch of the channel.

A shut-off nozzle includes a nozzle body portion having an in-nozzle flow path formed therein, and a needle valve that is inserted into the nozzle body portion coaxially with the nozzle body portion and is configured to open and close an outlet of the in-nozzle flow path. A cylindrical portion is formed in the vicinity of a tip portion of the needle valve. A cylindrical hole portion is formed in the vicinity of a tip portion of the in-nozzle flow path, the cylindrical hole portion being a cylindrical hole. The cylindrical portion is configured to be fitted into the cylindrical hole portion in a case where the needle valve is driven in a forward direction.

An injection nozzle is attachable to a tip end of a heating cylinder and having an in-nozzle flow path formed therein. The injection nozzle is attached to the heating cylinder by being pressed against the heating cylinder by a nozzle pressing member that is fixed to an end surface of a tip end of the heating cylinder. An outer peripheral surface of the injection nozzle has a sensor hole that is opened at a position contacting the nozzle pressing member, and a temperature sensor is inserted into the sensor hole.

An injection molding apparatus (10) comprising: one or more valves each comprised of a valve pin (1040, 1041, 1042) adapted to be driven upstream and downstream through a downstream channel (1006) that has a downstream channel portion (1006ds) that has a control surface (1008), the control surface (1008) forming a channel or restriction gap (CG, 1006rg), the valve pin (1041) being controllably drivable upstream and downstream through the channel or restriction gap (CG, 1006rg) at a single selected rate of upstream acceleration up to a selected reduced upstream velocity that is less than a maximum velocity at which the valve pin (1041) is drivable, the size or configuration of the channel or restriction gap (CG, 1006rg) and the single selected rate of upstream acceleration being selected in combination with each other to control flow of injection fluid (18) through the channel gap (CG, 1006rg).

Disclosed herein are novel methods for forming a polymer part including providing an injection molding system with a shut-off nozzle, where the shut-off nozzle includes a main body, a nozzle tip body, a flow path through the main body and the nozzle tip body, a nozzle tip, and a shut-off mechanism. The nozzle tip includes an internal passage and a cooling mechanism. The shut-off mechanism includes a passageway intersecting the flow path at an angle and a pin positioned in the passageway. The method further includes the steps of initiating an injection molding cycle by injecting molten polymer through the shut-off nozzle into a cavity of a mold, actuating the shut-off mechanism to move the pin in the passageway into the intersection of the passageway and flow path, and initiating the cooling mechanism to solidify molten polymer in the nozzle tip to form a solid slug.