A method and apparatus for injection molding of plastic material into a cavity of a mold by means of at least one injector whose opening and closing occurs through an electronic control unit and wherein an undesired opening of the mold caused by any overpressure of the plastic material injected into the cavity of the mold is detected by means of transducers and corrected by means of the electronic control unit. The transducers are arranged outside the cavity of the mold.

A valve-gating injection molding apparatus is disclosed. The valve gating injection molding apparatus has a manifold with a manifold channel extending therethrough and a nozzle coupled to the manifold and having a nozzle channel in fluid communication with the manifold channel A valve pin extends across the manifold and through the nozzle channel. An actuator coupled to the valve pin for translating the valve pin between open and closed positions. A plurality of mold plates forming an enclosure to house the manifold, the plurality of mold plates defining an egress passageway through which the valve pin extends and a diversion chute that intersects the egress passageway at an angle.

Disclosed is a guide bushing for the guiding and sealing of a closing needle of a needle valve nozzle of an injection moulding apparatus, the guide bushing having a main part and a fastening element, wherein the main part has a through-opening for the closing needle, wherein the through-opening comprises at least one guiding portion, which encloses the closing needle with slight movement play, wherein the through-opening comprises at least two expansion portions, whose diameter in each case is larger than that of the at least one guiding portion. The guide bushing moreover comprises a fastening element, which is securable to the main part, wherein a seal element is arranged between the fastening element and the main part, bearing against the entire circumference of a closing needle inserted into the through-opening.

An injection molding apparatus and method for adjusting the axial position of a valve pin in an injection molding system, the apparatus comprising: a top clamp plate, a heated manifold receiving and distributing an injection fluid to an exit of a fluid delivery channel to a cavity of the mold, an actuator comprising a housing having a chamber enclosing a drive member for driving a valve pin along an axial path of travel, the actuator housing slidably mounted and adapted for controlled upstream and downstream movement of the drive member along a path complementary to the axial path of travel of the valve pin, a mounting plate and an axial position adjustment screw screwably mounted within the mounting plate upstream of the housing of the actuator for controllably moving the valve pin to selectable starting or ending injection cycle axial positions.

Disclosed is a technology for eliminating the need for the adjustment of imbalance in an injection molded product and also enabling multi-cavity molding, a method of multi-cavity injection molding including: a dividing step of dividing a molten resin material into a plurality of portions; a resin density adjustment step of adjusting a resin density distribution; and a filling step of filling the molten resin material into a region where the molten resin material is formed into a molded product. The method of multi-cavity injection molding has a configuration containing a combined-use step which includes both a hot runner step and a cold runner step. The combined-use step is dividing the molten resin material from the hot runner to the plurality of cold runners through a spool and a branch runner. A plurality of series of steps from the dividing step to the filling step is concurrently performed in one mold.

Systems and methods for controlling the closing speed of valve gated nozzles are disclosed. In one embodiment, a hot runner have a valve gated nozzle including a valve stem movable between an open position and a closed position is provided. The valve stem is moved at a first speed for a first portion of valve stem closure and a second speed for a second end portion of the valve stem closure.

Injection unit for injection molding of plastic material including: an injection nozzle; a closure pin; and a guide and cooling assembly, interposed between the back driving plate and the hot distribution plate, in turn comprising: a guide and seal element for guiding the axial motion of the closure pin; a cooling ring; and pressure means configured to press the cooling ring directly and against the back driving plate; wherein the guide and seal element is slidably coupled, at an upper end, with a central hole of the cooling ring, and is fixed integrally, at the other end, to the hot distribution plate; and the cooling ring is able to slide laterally with respect to the back driving plate to recover the differences in thermal expansion between the hot distribution plate and the back driving plate and to transmit heat from the guide and seal element towards the back driving plate.

A method and apparatus for injection molding of plastic material into a cavity of a mold by means of at least one injector whose opening and closing occurs through an electronic control unit and wherein an undesired opening of the mold caused by any overpressure of the plastic material injected into the cavity of the mold is detected by means of transducers and corrected by means of the electronic control unit. The transducers are arranged outside the cavity of the mold.

A runner for supplying resin to a cavity includes a sprue that is supplied resin from a nozzle of an injection molding machine, a first path formed in the runner, where the resin flows in the first path from the nozzle when the nozzle connects to the sprue, a first pin that moves to a first position to increase the size of the first path before the resin is supplied to the first path and moves to a second position to decrease the size of the first path before the nozzle separates from the sprue.

A method for injection molding of plastic material by means of at least one injector whose pin valve can be displaced between a fully closed position and a maximum open position in a controlled fashion according to a position and speed of the pin valve. During displacement of the pin valve from the fully closed position to the maximum open position, and/or vice versa, the pin valve is stopped in intermediate positions and the displacement speed thereof is uniform and constant. An initial opening step at maximum speed and one or more steps of inversion of the motion of the pin valve can be provided for.