Controlled valve pin movement based on cavity sensor feedback

Apparatus for performing an injection molding cycle in an injection molding apparatus, the apparatus comprising:

• a manifold that receives an injection fluid material, the manifold having or communicating with a delivery channel that delivers the injection fluid mold material under an injection pressure to two or more gates each leading to an associated mold cavity,
• an actuator associated with each respective gate,
• each actuator being drivably interconnected to a valve pin drivable upstream and downstream along a path of travel having a selected stroke length that extends between a gate closed position, a selected maximum flow position at which the injection fluid material flows at a maximum rate through the gate into the cavity and one or more selectable intermediate positions between the first position and the maximum flow position,
• each actuator being controllably drivable to position an interconnected valve pin at the first, one or more selectable intermediate and maximum flow positions over the course of an injection cycle,
• each gate having a downstream sensor that senses a selected downstream condition of the injection fluid material at a position within each associated mold cavity that is downstream of each associated gate, the downstream sensor generating a response signal upon sensing the selected condition of the injection fluid material when the injection fluid material has flowed to the downstream position of the downstream sensor,
• each gate having an upstream sensor that senses a selected upstream condition of the injection fluid material at a position within each associated mold cavity that is upstream of the downstream position associated with each gate, the upstream sensor generating a response signal upon sensing the selected condition of the injection fluid material when the injection fluid material has flowed to the upstream position of the upstream sensor,
• a controller containing predetermined data representing as a standard for a selected one of the gates, the amount of time elapsed between the time at which the upstream sensor associated with the selected one of the gates first senses the selected upstream condition of the injection fluid material and the time at which the downstream sensor associated with the selected one of the gates first senses the selected downstream condition of the injection fluid material flowing into the associated mold cavity,
• the upstream and downstream sensors of each of the other gates other than the selected one of the gates each sensing the selected upstream and downstream conditions of the injection fluid material and sending response signals to the controller on performance of each successive injection cycle by the apparatus,
• the controller receiving the response signals from the sensors associated with each of the other gates on performance of each successive injection cycle performed by the apparatus and calculating the amount of time elapsed between the time at which the upstream sensor associated with each of the other gates first senses the selected upstream condition of the injection fluid material and the time at which the downstream sensor associated with the selected one of the gates first senses the selected downstream condition of the injection fluid material flowing into the associated mold cavity,
• the controller including instructions that compare the amount of standard elapsed time with the calculated amount of elapsed time associated with each of the other gates,
• the controller including instructions that adjust the velocity or position of each of the actuators associated with each of the other gates to drive the valve pins associated with each of the other gates at one or more velocities or to one or more positions during one or more successive injection cycles based on the compared amounts of time such that the amount of time elapsed between the time that the upstream sensors associated with the other gates first sense the selected upstream condition of the injection fluid material and the time that the downstream sensors associated with the other gates first sense the selected downstream condition approaches or matches the standard amount of elapsed time.

A method of performing an injection molding cycle in an injection molding apparatus comprised of:

• a manifold that receives an injection fluid material, the manifold having or communicating with a delivery channel that delivers the injection fluid mold material under an injection pressure to two or more gates each leading to an associated mold cavity,
• an actuator associated with each respective gate,
• each actuator being drivably interconnected to a valve pin drivable upstream and downstream along a path of travel having a selected stroke length that extends between a gate closed position, a selected maximum flow position at which the injection fluid material flows at a maximum rate through the gate into the cavity and one or more selectable intermediate positions between the first position and the maximum flow position,
• each actuator being controllably drivable to position an interconnected valve pin at the first, one or more selectable intermediate and maximum flow positions over the course of an injection cycle,
• a downstream sensor that senses a selected downstream physical condition of the injection fluid material at a position within an associated mold cavity that is downstream of an associated gate, the downstream sensor generating a signal corresponding to the sensed values,
• an upstream sensor that senses a selected upstream physical condition of the injection fluid material at a position within an associated mold cavity that is upstream of the downstream position,
• the method comprising the steps of:
• selecting as a standard for all of the gates, the amount of time elapsed between the time at which the upstream sensor associated with a gate first senses the selected upstream condition of the injection fluid and the time at which the downstream sensor first senses the selected downstream condition of the injection fluid material flowing into the associated mold cavity of a gate,
• performing one or more subsequent injection cycles and for each of the gates sensing the selected upstream and downstream physical condition of the injection fluid material at the upstream and downstream positions with the upstream and downstream sensors associated with each of the other gates,
• recording the amount of time elapsed between the time at which the upstream sensor associated with each of the gates first senses the selected upstream condition of the injection fluid and the time at which the downstream sensor associated with each of the gates first senses the selected condition of the injection fluid material flowing into the associated cavities of each of the gates,
• comparing the recorded amounts of time elapsed associated with each of the gates with the selected standard amount of time,
• adjusting position or velocity of the actuators or valve pins associated with each of the gates during each subsequent injection cycle such that the amount of time elapsed between the time at which the upstream sensor first senses the selected upstream condition and the time at which the downstream sensor first senses the selected downstream condition of the injection fluid material approaches or matches the selected standard amount of elapsed time.

An apparatus for performing an injection molding cycle in an injection molding apparatus, the apparatus comprising:

• a manifold that receives an injection fluid material, the manifold having or communicating with a delivery channel that delivers the injection fluid mold material under an injection pressure to two or more gates each leading to an associated mold cavity,
• an actuator associated with each respective gate,
• each actuator being drivably interconnected to a valve pin drivable upstream and downstream along a path of travel having a selected stroke length that extends between a gate closed position, a selected maximum flow position at which the injection fluid material flows at a maximum rate through the gate into the cavity and one or more selectable intermediate positions between the first position and the maximum flow position,
• each actuator being controllably drivable to position an interconnected valve pin at the first, one or more selectable intermediate and maximum flow positions over the course of an injection cycle,
• each gate having a downstream sensor that senses a selected downstream condition of the injection fluid material at a position within each associated mold cavity that is downstream of each associated gate, the downstream sensor generating a response signal upon sensing the selected condition of the injection fluid material when the injection fluid material has flowed to the downstream position of the downstream sensor,
• each gate having an upstream sensor that senses a selected upstream condition of the injection fluid material at a position within each associated mold cavity that is upstream of the downstream position associated with each gate, the upstream sensor generating a response signal upon sensing the selected condition of the injection fluid material when the injection fluid material has flowed to the upstream position of the upstream sensor,
• a controller containing predetermined data representing as a standard for each of the gates, the amount of time elapsed between the time at which the upstream sensor associated with a gate first senses the selected upstream condition of the injection fluid material and the time at which the downstream sensor associated with a gate first senses the selected downstream condition of the injection fluid material flowing into the associated mold cavity,
• the upstream and downstream sensors of each of the gates each sensing the selected upstream and downstream conditions of the injection fluid material and each sending response signals to the controller on performance of each successive injection cycle by the apparatus,
• the controller receiving the response signals from the sensors associated with each of the gates on performance of each successive injection cycle performed by the apparatus and calculating the amount of time elapsed between the time at which the upstream sensor associated with each of the gates first senses the selected upstream condition of the injection fluid material and the time at which the downstream sensor associated with each of the gates first senses the selected downstream condition of the injection fluid material flowing into the associated mold cavity,
• the controller including instructions that compare the standard amount of elapsed time with the calculated amount of elapsed time associated with each of the gates,
• the controller including instructions that adjust the velocity or position of each of the actuators associated with each of the gates to drive the valve pins associated with each of the gates at one or more velocities or to one or more positions during one or more successive injection cycles based on the compared amounts of time such that the amount of time elapsed between the time that the upstream sensors associated with each of the gates first sense the selected upstream condition of the injection fluid material and the time that the downstream sensors associated with each of the gates first sense the selected downstream condition approaches or matches the standard amount of elapsed time.