Injection Nozzle Flow Control for Uniform Mold Filling
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Solution Overview
Problem
In injection molding, especially for flat and elongated parts, it is challenging to fill the cavity uniformly due to temperature reduction and resulting inhomogeneities, and the cascade injection molding process often leads to explosive discharge of melt at downstream nozzles, causing flow line markings.
Innovation Solution
An injection molding system with a piston-driven actuator system, electronically controlled flow valves, and sensors to manage pressure and flow timing, preventing explosive discharge by adjusting the opening of nozzles and regulating pressure flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple feed orifices are used to fill the cavity uniformly, then the filling completeness is improved, but flow line markings appear on the surface
Solution Approach 1:
The patent applies preliminary action by opening nozzles in a predetermined sequence before the melt reaches their feed orifices. The controller opens downstream nozzles progressively as the flow front approaches, ensuring that melt from different nozzles arrives at the cavity simultaneously without creating flow lines. This timing control prevents the harmful effect while maintaining uniform filling.
2Productivity
If downstream nozzles are opened suddenly at full pressure to ensure filling, then the filling speed is improved, but explosive discharge occurs causing flow line markings
Solution Approach 1:
The patent applies dynamics by making the nozzle opening process gradual rather than sudden. The controller opens downstream nozzles progressively over time, allowing the melt to discharge controlled amounts sequentially. This dynamic control prevents explosive discharge while maintaining adequate filling speed, resolving the contradiction between productivity and harmful effects.
3Area of stationary object
If the melt flows through long distances to reach distant areas of the cavity, then the coverage is improved, but the temperature is reduced causing inhomogeneities
Solution Approach 1:
The patent applies segmentation by dividing the single long flow path into multiple shorter segments through several nozzles positioned at different locations. Each nozzle delivers melt over a shorter distance to its local area of the cavity, preventing excessive cooling. This segmented approach maintains melt temperature and ensures homogeneous structure throughout the entire cavity coverage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures precise control of the injection process, preventing flow line markings and ensuring uniform filling of the cavity, improving the quality of molded parts by managing pressure and flow timing.
Implementation Method 1
The actuator system comprises at least one piston drive (10) with at least two pressure line connectors (CP2, CP3) for driving a piston (11) to open or close a molding nozzle (D1 to D3).
Implementation Method 2
The changeover valve (V) establishes the connection to the general pressure fluid system and controls the pressure flow to and from the actuator system (100). The fluid can be a hydraulic fluid or air.
Implementation Method 3
an electronically adjustable flow control valve (20) having a first pressure line connector and a second pressure line connector, wherein the first pressure line connector of the adjustable flow control valve (20) is connected to the first pressure line (L1) to establish a connection to the first pressure line connector (CV1) of the changeover valve (V).
Implementation Method 4
at least one electronic sensor (P1, P2, P3) for detecting the flow (P1, P2, P3) sensing the flow rate in the first, second and/or third pressure lines (L1, L2, L3).
Implementation Method 5
the controller (C), which is connected to the adjustable flow control valve (20) and to the at least one sensor (P1, P2, P3), is configured to electronically adjust the flow control valve (20), depending on information of the at least one sensor (P1, P2, P3).
Data Source
AI summary
An actuator system for an injection molding system includes a double acting pressurized fluid actuator having a piston drive movable in a cylinder space, a flow control valve for regulating a flow rate of pressurized fluid to and/or from the cylinder space, a flow sensor for detecting the flow rate of pressurized fluid to and/or from the cylinder space, and an electronic controller for controlling the flow control valve to regulate the flow rate of pressurized fluid to and/or from the cylinder space depending on the flow rate detected by the flow sensor.