Magnetic Valve Pin Coupling for Injection Molding
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Solution Overview
Problem
In injection molding, improper operation of valve pins can lead to damage due to collisions with foreign objects or seizing, especially when multiple valve pins are actuated together, resulting in costly and time-consuming replacements.
Innovation Solution
A magnetic coupling system is implemented where the valve pin is magnetically attached to an actuated part, allowing it to decouple from the actuated part if a stopping force exceeds the magnetic attraction, thereby reducing damage by allowing unobstructed valve pins to continue moving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple valve pins are ganged together to be actuated in unison by a common valve pin plate, then the productivity and synchronization of gate closing is improved, but the risk of damage increases when a single valve pin encounters a blockage or seizing condition
Solution Approach 1:
The patent divides the previously rigidly connected valve pin system into separable magnetic couplings. Each valve pin is magnetically coupled to the valve pin plate rather than being rigidly attached, allowing individual valve pins to decouple when encountering obstructions while others remain connected. This segmentation maintains synchronized operation under normal conditions while providing isolation protection when needed.
Solution Approach 2:
The patent introduces magnetic coupling as an intermediary between the valve pin plate and individual valve pins. This magnetic field-based connection acts as a mediator that can dynamically adjust its coupling strength, allowing force transmission during normal operation but permitting separation when excessive force is encountered, thus protecting the system from damage.
2Force
If a valve pin is rigidly attached to the actuated part, then the force transmission and actuation reliability is improved, but the damage to valve pin or surrounding components occurs when a stopping force is encountered
Solution Approach 1:
The patent transforms the static rigid connection into a dynamic magnetic coupling system. The magnetic coupling allows the connection between the valve pin plate and valve pin to dynamically adjust - maintaining strong force transmission during normal operation but automatically decoupling when excessive stopping forces are encountered, preventing damage while ensuring reliable actuation under normal conditions.
Solution Approach 2:
The magnetic coupling serves as a pre-configured protective mechanism that cushions against excessive forces before damage can occur. The magnetic field provides a controlled coupling strength that naturally limits the maximum force transmitted to the valve pin, preventing catastrophic failure from collisions or seizing conditions.
3Reliability
If the valve pin is magnetically coupled to the actuated part, then the damage risk is reduced by allowing separation under excessive force, but the coupling strength must be carefully controlled to maintain normal operation
Solution Approach 1:
The patent utilizes parameter changes in magnetic coupling strength to achieve the desired functionality. By carefully selecting magnetic material properties, magnet strength, and geometric parameters, the system is designed so that the magnetic coupling strength naturally transitions from a strong bonded state during normal operation to a decoupled state when excessive forces are applied, providing protection without requiring complex active control mechanisms.
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 prevents damage to valve pins and surrounding components by allowing the valve pin to separate from the actuated part when encountering obstructions, reducing the risk of damage and maintaining the operation of other valve pins.
Implementation Method 1
the valve pin is magnetically coupled to the actuated part
Implementation Method 2
When a stopping force applied to the valve pin, as the valve pin is being closed, is greater than a force of magnetic attraction holding the valve pin to the actuated part, the valve pin separates from the actuated part
Data Source
AI summary
An actuated part, such as a valve pin plate or actuator piston, is movable in forward and rearward directions. A coupling part is located rearward of the actuated part and held in position by magnetic attraction between the coupling part and the actuated part. A valve pin is coupled to the coupling part. The valve pin extends in the forward direction for opening and closing a mold gate. When a stopping force applied to the valve pin is greater than a force of the magnetic attraction between the coupling part and the actuated part, the actuated part moves away from the coupling part in the forward direction, thereby reducing the stopping force on the valve pin.