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.

An obturation valve is described for controlling a flow of molten material exiting from a nozzle into a mold cavity, comprising a channel for the molten material extending along a first axis, two or more obturating members that are mounted movably along a respective second axis inclined at an acute angle with respect to the first axis and so that a free end of each obturating member can move and converge towards the same point inside the channel. The free ends of the obturating members can join at said point to compose a blocking/closing bulkhead for the molten material.

An obturation valve is described for controlling a flow of molten material exiting from a nozzle into a mold cavity, comprising a channel for the molten material extending along a first axis, two or more obturating members that are mounted movably along a respective second axis inclined at an acute angle with respect to the first axis and so that a free end of each obturating member can move and converge towards the same point inside the channel. The free ends of the obturating members can join at said point to compose a blocking/closing bulkhead for the molten material.

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 manufacturing apparatus includes a defining portion, a plunger, and a valve member. The defining portion defines a supply port, a discharge port, and a resin channel. The resin channel includes a reserving portion, a first partial channel connecting the supply port and the reserving portion, a second partial channel connecting the reserving portion and the discharge port, a relay channel connecting the first partial channel, the reserving portion and the second partial channel, and a connecting channel connecting the first partial channel and the second partial channel. The plunger discharges the molten resin reserved in the reserving portion. The valve member is provided in the connecting channel and the second partial channel. The first partial channel and the relay channel are connected to the connecting channel so as to intersect with the connecting channel. The valve member includes a first valve portion and a second valve portion.

A manufacturing apparatus includes a defining portion, a plunger, and a valve member. The defining portion defines a supply port, a discharge port, and a resin channel. The resin channel includes a reserving portion, a first partial channel connecting the supply port and the reserving portion, a second partial channel connecting the reserving portion and the discharge port, a relay channel connecting the first partial channel, the reserving portion and the second partial channel, and a connecting channel connecting the first partial channel and the second partial channel. The plunger discharges the molten resin reserved in the reserving portion. The valve member is provided in the connecting channel and the second partial channel. The first partial channel and the relay channel are connected to the connecting channel so as to intersect with the connecting channel. The valve member includes a first valve portion and a second valve portion.

A shut-off nozzle for a molding machine, comprising a fluid housing having at least one fluid channel, wherein the at least one fluid channel is designed to guide a-preferably liquid and/or plastic-fluid and a valve element which is mounted rotationally about an axis of rotation relative to the fluid housing and which passes through the fluid channel and has at least one through-opening for the passage of the fluid, wherein a flow cross-section between the fluid channel and the through-opening can be varied by a rotational movement of the valve element and thus a flow rate of the fluid can be influenced, wherein the valve element is mounted in the valve housing in a floating manner along the axis of rotation.

A shut-off nozzle for a molding machine, comprising a fluid housing having at least one fluid channel, wherein the at least one fluid channel is designed to guide a-preferably liquid and/or plastic-fluid and a valve element which is mounted rotationally about an axis of rotation relative to the fluid housing and which passes through the fluid channel and has at least one through-opening for the passage of the fluid, wherein a flow cross-section between the fluid channel and the through-opening can be varied by a rotational movement of the valve element and thus a flow rate of the fluid can be influenced, wherein the valve element is mounted in the valve housing in a floating manner along the axis of rotation.

Shut-off nozzle for a molding machine, comprising a valve housing having at least one fluid channel, wherein the at least one fluid channel is designed to guide apreferably liquid and/or plasticfluid and a valve element which is rotationally mounted about an axis of rotation relative to the valve housing, which valve element has at least one through-opening for the passage of the fluid and is designed to vary a flow cross-section between the at least one fluid channel and the at least one through-opening by carrying out a rotational movement and thus to influence a flow of the fluid, wherein the at least one through-opening has a cross-section in a plane orthogonal to its longitudinal extension through the valve element which has a larger dimension along the axis of rotation of the valve element than perpendicular thereto.