In a method for operating an injection moulding machine in the absence of a backflow barrier, plastic melt is injected by a plasticising device into a cavity in a screw antechamber of a plasticising screw adapted to rotate about a longitudinal axis and to move translationally by a drive unit during an injection phase and a holding-pressure phase. A rotational drive of the drive unit is controlled such that a speed of the plasticising screw causes overlay of a backflow of the plastic melt from the screw antechamber back into screw threads of the plasticising screw by an opposing delivery flow as a result of a rotation of the plasticising screw due to a translational injection movement of the plasticising screw. A differential flow is established from the backflow and the opposing delivery flow and influenced at least during the injection phase by influencing the speed of the plasticising screw.

Embodiments within the scope of the present disclosure are directed to external sensor kits that may be included in new injection molds or retrofitted into existing injection molds in order to approximate conditions within a mold, such as pressure or the location of a melt flow front. Such kits are designed to amplify meaningful measurements obtained by the external sensor kit so that noise measurements do not prevent the approximation of conditions within a mold. In some embodiments within the scope of the present disclosure, an external sensor kit includes a strain gauge sensor, a coupon, a support bracket, and a hammer. The strain gauge sensor is placed on a surface of the coupon and measures the strain in the coupon.

A process is provided for making a walled structure using an injection molding apparatus. The apparatus has a molding space formed between a mold cavity and an inner core disposed within the mold cavity. The molding space defines a shape of the structure. The process includes injecting molding material into the molding space, moving or retaining a portion of a movable impression member protruding from the inner core within a portion of the molding space so as to create a recess within an inner wall of the structure, and retracting the impression member into the inner core such that the impression member is cleared from the molding space. Precision control in forming the impression member is provided by a closed-loop configuration using a sensor that measures a molding space parameter (e.g., temperature), optionally in combination with a servo drive for activating the impression member.

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 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.

An injection molding apparatus and method of fabricating a molded part are provided. The apparatus may include a barrel, a nozzle enclosing an end of the barrel and defining an opening in fluid communication with an inside of the barrel, and an extrusion screw positioned at least partially inside the barrel and rotatable relative to the barrel. The extrusion screw may include a screw tip. Relative axial movement between the barrel and the extrusion screw may open or close the opening of the nozzle to permit or prevent, respectively, material flow through the opening of the nozzle. The method may include clamping a mold, opening a nozzle, rotating the extrusion screw to pump a molten material into the mold until the mold is filled, closing the nozzle, and unclamping the mold to release a molded part.

To provide a new foam molding method and injection molding machine capable of solving variation in a wall thickness and a foamed state, sensor corrosion, a complexity of sensor positioning, and the like. The above-described problem is solved by a foam molding method comprising a resin filling step of filling a mold (2), clamped by a predetermined mold clamping force (Pc), with a resin (R) at a predetermined molding injection pressure (Pi), a filling stopping step of stopping the filling of the resin (R) when, while monitoring a mold gap (Lm) of the mold (2) during the filling, a predetermined mold gap value set in advance is reached, a surface layer curing and filled resin cooling step of curing a surface layer of the resin (R) for a certain time and cooling the filled resin (R) for a certain time after the filling of the resin (R) is stopped, a volume controlling step of controlling a volume increase by reducing the mold clamping force after curing the surface layer of the resin (R) for a certain time, and a taking out step of taking out a foam-molded product by opening the mold (2) after the volume control is performed and after cooling the filled resin (R) for a certain time.

A method and system for co-injection molding of two molten plastic materials that allows monitoring and utilization of injection pressure and optionally melt pressure and/or flow front pressure during an injection run. A controller alters the injection pressure so as to achieve and maintain optimal or desired ratios of injection pressure, and optionally melt pressure and/or flow front pressure, of the two molten plastic materials. This allows for more precise part manufacture, including reducing the thickness of a skin or shell layer compared to a core layer of a molded part.

A melt temperature sensing kit includes a housing and a cup. The housing defines a cavity and has an outer periphery configured to be received by a platen of an injection molding machine. The cup has a proximate end and a distal end and is configured to be received within at least a portion of the cavity. The cup includes a base enclosing the distal end of the cup and a sidewall extending from the base, the sidewall defining a first aperture at the proximate end of the cup, a second aperture disposed between the proximate end and the distal end of the cup, and an internal volume. The first aperture, the second aperture, and the internal volume cooperate to define a flow path. At least one of the housing and the cup facilitate measurement of a shot flow temperature as part of a melt temperature measurement process.

An injection molding system comprising: a first selected valve, one or more downstream valves, delivering a fluid to a mold cavity, at least one fluid property sensor that detects a flow front of fluid material flowing downstream through the mold cavity at a trigger location within the cavity disposed between the first gate and at least one selected downstream gate, a controller instructing an actuator associated with the downstream gates to open the gates at a predetermined open gate target time on a first injection cycle, each valve associated with a position sensor that detects opening of a gate at an actual open gate time to the controller, the controller automatically adjusting time of instruction to open the gates on a subsequent injection cycle by an adjustment time equal to any delay in time between the predetermined open gate target time and the actual open gate time.