A method of performing an injection cycle having a duration comprising: beginning the injection cycle with the valve pins associated with two or more nozzles in a gate closed position, selecting a first one of the two or more nozzles and controllably driving its associated valve pin from the gate closed position to a selected first axial upstream position, upon downstream flow of the injection fluid through a cavity the preselected distance, controllably driving the valve pin associated with the other of the two or more nozzles to a selected second axial position upstream, holding or controllably driving the valve pin associated with the first one of the two or more nozzles in or to one or more reduced flow axial upstream positions that are partially closed.

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 method of monitoring and controlling a molding clamping apparatus in an injection molding or other molding process is disclosed. The method includes creating a target strain profile, receiving a deviation limit, receiving a change in strain relating to a mold while it is closing from a first strain gauge, identifying a deviation from a target strain profile based on the output from the first strain gauge, determining that the deviation exceeds the deviation limit, and adjusting the rate or force of clamp movement. The target strain profile may have a first portion relating to a clamp closing process, a second portion relating to a filling process, and a third portion relating to a clamp opening process. The first portion relating to the clamp closing process may include an intermediate portion relating to a coining process having an intermediate clamp force setpoint.

Non-time dependent calculated variables based on measured strain are used to effectively determine an optimal hold profile for an expanding crosslinking polymer part in a mold cavity. A system and/or approach may first inject molten expanding crosslinking polymer into a mold cavity, then measure strain at the mold cavity or at another location within the injection molding system, and then calculate at least one non-time dependent variable during an injection molding cycle. Next, the system and/or method commences a hold profile for the part, and upon completing the hold profile, the part is ejected from the mold cavity, whereupon a cure profile is commenced.

An injection molding apparatus, comprising: an injection molding machine; a distribution manifold having a distribution channel, a clamp device arranged to clamp together, under a selected clamp force, a mold system having a plurality of mold cavities one or more first downstream channels fluidly coupled to the distribution channel; one or more first gates arranged to deliver injection fluid to a first cavity; one or more second downstream channels fluidly coupled to the distribution channel; one or more second gates arranged to deliver injection fluid to a second cavity; a control system adapted to: instruct the first upstream valve and a second upstream valve; and at least one downstream valve having a valve pin having a control surface for controlling flow of injection fluid.

When an injection molding machine performs molding, the mold clamping force on the mold is adjusted on the basis of a mold displacement of the mold or the injection peak pressure and injection foremost position so that the molding is performed without causing flash and by an appropriate mold clamping force with which energy can be reduced. The amount of mold displacement and also the injection peak pressure and the injection foremost position are monitored during automatic operation. If there occurs no mold displacement change exceeding a threshold or if there occurs no injection peak pressure anomaly or injection foremost position anomaly exceeding thresholds, the automatic operation is continued. If the mold displacement change occurs or if the injection peak pressure anomaly and the injection foremost position anomaly occur, the operation of the injection molding machine is stopped.

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.

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.

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.

Disclosed herein is an injection molding method for making optical thermoplastic lenses using 3D—printed functional wafers. The method employs a variable injection molding cavity temperature that is heated to at least wafer Tg—10° C.