Metering Controller Screw Reverse Rotation Check Valve
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Solution Overview
Problem
Existing injection molding machine technologies face challenges in accurately metering resin due to backward flow of molten resin, which leads to inconsistent product quality and requires high resin pressure to close check valves, causing issues with various molds.
Innovation Solution
A metering controller that includes a screw advancing/retreating unit, a screw rotating unit, a resin pressure detection unit, and a pilot injection unit, where the screw is reverse rotated before advancing to create a pressure difference that allows the check valve to be closed at a low pressure, avoiding high resin pressure and ensuring accurate metering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a check valve is used to prevent backflow of molten resin, then metering accuracy is improved, but the valve may fail to close timely due to delayed operation, causing injection amount errors
Solution Approach 1:
The screw is advanced before the check valve operation to create a pressure difference that ensures timely valve closure. By performing this preliminary action of advancing the screw to build pressure, the system guarantees the valve closes at the correct moment without delay, resolving the reliability issue while maintaining metering accuracy
2Reliability
If high resin pressure is applied to close the check valve, then valve closure reliability is improved, but molding problems occur with various mold types
Solution Approach 1:
The screw advance speed and pressure application are dynamically adjusted based on detection signals. The system transitions from a static high-pressure approach to a dynamic control method where the screw advances at controlled speeds and pressure is applied progressively, ensuring reliable valve closure while adapting to different mold types and avoiding molding problems
3Reliability
If the screw is advanced to increase resin pressure for check valve closure, then valve closure is achieved, but the process takes time and reduces productivity
Solution Approach 1:
A detection signal is used to monitor the screw advance position and resin pressure in real-time. This feedback mechanism allows the system to advance the screw efficiently, detect when the desired pressure is reached, and immediately proceed to the next step, minimizing unnecessary delays and improving productivity while ensuring reliable valve closure
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
Enables reliable and steady closure of the check valve at a lower pressure, preventing resin flow backward and maintaining accurate resin injection, thus improving product quality and accommodating various mold types without high pressure issues.
Implementation Method 1
a pressure difference is produced between the front and rear sides of a check valve to retreat the valve
Implementation Method 2
a predetermined pressure or position is reached
Data Source
AI summary
During metering, a screw is retreated to a preset metering completion position while it is being forwardly rotated. Pilot injection is performed such that the screw is reversely rotated and advanced so that a resin pressure reaches a predetermined compression pressure, during a time period between the end of the metering and the start of injection. The screw reverse rotation is continued before the screw advance is started for the pilot injection. In this way, a check valve can be closed at a relatively low pressure such that precision metering can be achieved.