Apparatus and method for detecting a position of an actuator piston driving a valve pin in an injection molding system. The apparatus includes an actuator housing having a body portion, surrounding an axial bore, of a substantially non-magnetic and/or magnetically permeable material, a piston, movable within the axial bore for driving a valve pin, the piston including a magnetic member generating a magnetic field such that axial movement of the piston in the bore modifies the magnetic field according to the position of the piston relative to a detection position, and a magnetic field detector attached to an exterior surface of the body portion at the detection position for detecting the magnetic field associated with the position of the piston and generating an output signal determined by the piston position.

An apparatus for controlling the rate of flow of mold material to a mold cavity, the apparatus comprising: an injection molding machine and a manifold; an actuator interconnected to a valve pin having a tip end; a valve system in fluid communication with the actuator to drive the actuator at one or more rates of travel, the valve system having a start position, one or more intermediate drive rate positions and a high drive rate position, the start position holding the valve pin in a gate closed position; a controller that instructs the valve system to move from the start position to the one or more intermediate drive rate positions and to remain in the one or more intermediate drive rate positions for one or more corresponding predetermined amounts of time.

A molding method for the production of articles molded by injecting plastic material into a mold cavity by a plurality of injectors electrically sequentially actuated under an electronic control according to a cycle providing for a step for filling the mold cavity, followed by a step for packing the plastic material in the mold cavity. Each injector, regardless of both its position with respect to the mold cavity and its opening speed, is controlled in at least one of the following control modes: i) partially closing the injector from a maximum open condition to a less opened condition in the filling step, ii) setting the injector in a partially open condition and then opening the injector to a more opened condition, in the packing step.

Injection molding apparatuses and methods wherein a valve pin is controllably driven upstream and downstream along an axis between a first closed position where the tip end of the valve pin obstructs the gate to prevent the injection fluid from flowing into the cavity, a full open position and one or more intermediate positions, wherein the valve pin is drivable to be disposed or held in a selected intermediate position for a selected period of time during the course of an injection cycle where the tip end of the valve pin restricts flow of injection fluid through the gate to the mold cavity.

Injection molding system having a flow control apparatus and method that controls the movement and/or rate of movement of a valve pin over the course of an injection cycle to cause the pin to move to one or select positions and/or to control the rate of movement of the pin over the course of the injection cycle. In one embodiment the method includes steps of: a) first controllably operating the actuator to drive the valve pin upstream beginning from the first closed position (50) to be moved to and held in a first selected position (51) for a first selected period of time during the course of an injection cycle, the first selected position (51) being the full open position; b) second controllably operating the actuator to drive the valve pin, during the injection cycle, downstream beginning from the first selected position (51) to be moved to and held in a second closed position (52) for a second selected period of time; c) third controllably operating the actuator to drive the valve pin, during the injection cycle, upstream beginning from the second closed position (52) to be moved to and held in a second selected position (53) for a third selected period of time, the second selected position being an intermediate position or the full open position; and d) fourth controllably operating the actuator to drive the valve pin, during the injection cycle, downstream beginning from the second selected position (53) to be moved to a third closed position (54).

An apparatus and method for eliminating mold lines when molding a part having ferromagnetic pigments is provided. A mold assembly having a mold with a cavity and valve gates is formed. Pucks are fitted at the gates to collect residual cold plastic. The calculation of a specific sequence and timing of the opening of the valve gates is determined based on a calculation of the total number of valve gates needed to fill a part while maintaining acceptable injection molding pressure. Once calculated, the gates are positioned around the mold cavity to balance flow length ratio. A primary gate is chosen for initial injection. The time for the material to flow from the first to the second gate is established. The second gate is opened after the flow front reaches the second gate. This pattern continues until all valve gates are opened.

An apparatus for controlling the rate of flow of fluid mold material comprising: a manifold, a valve pin having a pin axis, a pin connector and a stem, the valve pin being drivable into and out of open and closed positions relative to the gate, an electric actuator comprising an electric motor comprised of a motor housing that houses a drive shaft having a drive gear and a drive axis, a transmission comprised of a transmission gear having a gear axis, the drive gear, the transmission gear and the valve pin being drivably interconnected and arranged such that the drive axis and the gear axis are non-coaxially mounted or disposed relative to each other and the valve pin is drivable linearly along the pin axis, wherein one or the other of the motor housing or the transmission housing are removably attached to a top clamping or mounting plate that is mounted upstream of the manifold and fixedly interconnected to a mold.

A process includes: supplying a main resin from outer and inner flow channel, to a joined flow channel at a predetermined supply velocity for a predetermined time; supplying a second resin from a middle flow channel to the joined flow channel simultaneously with the main resin at a predetermined supply velocity for a certain time within the predetermined time; and sliding a shut-off pin to bring the pin forefront to a predetermined position near an outlet of the inner flow channel, open to the joined flow channel, before the second resin is supplied, or during a time starting after a time from the start of the second resin supply and ending with the termination of the supply, so that the velocity of main resin supply from the inner flow channel to the joined flow channel is reduced to a predetermined level by adjusting the degree of aperture for the outlet.

An injection molding apparatus comprising a manifold, an actuator having a piston that divides an enclosed actuator housing into upstream and downstream actuator drive chambers, the piston having an internal piston chamber and a piston bore that communicates flow of the drive fluid between one of the upstream or downstream actuator drive chambers and the internal piston chamber, a flow rate controller adapted to enable flow of drive fluid between one of the upstream or downstream actuator drive chambers and a source of drive fluid at a first low rate of flow over a selected first portion of the stroke length of the piston and at a second high rate of flow over a selected second portion of the stroke length of the piston.

A method of monitoring and controlling a sequential valve gate molding 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 first valve gate from a first strain gauge, identifying whether a deviation exists from a first portion of the target strain profile based on the output from the first strain gauge, determining whether any existing deviation exceeds the deviation limit, and adjusting the position of a first valve gate pin in the first valve gate if it does. The method may further include control of subsequent valve gates. Multiple strain gauges may be used to control a single valve gate, and/or each strain gauge may control more than one valve gate.