In-Mold Degassing Structure for Injection Molding
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Solution Overview
Problem
Existing mold vent structures require external control mechanisms and repetitive trial-and-error adjustments to manage gas release during injection molding and die casting, leading to defects like short shots and blowholes, especially with varying molten material flow rates and viscosities.
Innovation Solution
An in-mold gas vent structure with a sliding member and acceptor, actuated by an elastic member, that automatically opens and closes in response to the leading end of the molten material flow, allowing gas release without external control, and is adaptable to different material viscosities through non-linear gas release passages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a gas vent path with external control mechanisms is used, then gas can be released from the mold cavity, but the device complexity increases and requires repetitive trial-and-error adjustments
Solution Approach 1:
The sliding member automatically responds to the impelling force from the leading end of the molten material flow, opening the gas vent port without requiring external control mechanisms. The system serves itself by using the material flow's own energy to trigger the gas release action.
Solution Approach 2:
The patent replaces complex external control mechanisms (timers, sensors, actuators) with a simple mechanical sliding member that responds directly to the physical impelling force of the molten material, eliminating the need for electronic or mechanical control systems.
2Object-affected harmful factors
If the gas vent port remains open for gas release, then gas can be exhausted from the cavity, but molten material may leak through the vent port causing defects
Solution Approach 1:
The gas vent port dynamically changes from open to closed state based on the arrival of the molten material's leading end. The sliding member transitions positions in response to the impelling force, automatically adapting the vent port's state to the current phase of the injection process.
Solution Approach 2:
The sliding member is positioned in advance to allow gas venting during the initial phase of injection. When the leading end of the molten material arrives, it triggers the closing action before the bulk of the material can reach the vent port, preventing leakage.
3Manufacturing precision
If trial-and-error adjustments are made to control gas venting, then gas release timing can be optimized, but productivity decreases due to repetitive adjustments
Solution Approach 1:
The system automatically determines the optimal venting timing by responding to the actual arrival of the molten material's leading end, eliminating the need for operators to perform repetitive trial-and-error adjustments to optimize timing for different materials and conditions.
4Object-affected harmful factors
If a slidable core member with timer control is used, then gas venting can be controlled, but the ease of operation decreases due to complex setup requirements
Solution Approach 1:
The patent replaces timer-based control systems with a mechanical response system where the sliding member directly responds to the physical impelling force of the molten material, eliminating complex setup requirements and making the system easier to operate.
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 reduces the occurrence of defects by ensuring complete gas release before the molten material reaches the vent, improving productivity and eliminating the need for complex control systems, and can be easily integrated or detached from molds, reducing manufacturing steps and costs.
Implementation Method 1
a sliding member (10) that receives, from an opposite side, an impelling force exerted by an elastic member (14)
Data Source
Figure 1(A)~1(B)
Figure 2
Figure 3(A)~3(D)
AI summary
Provided are an in-mold degassing structure, which acts by using no external control means, and a mold having that structure. The degassing structure comprises a sliding member (10) for receiving the pushing force of an elastic member from the bottom side, and a sliding member acceptor (20) for accepting the sliding member (10) slidably in the vertical direction. The sliding member (10) includes a vertical bottomed hole (12) communicating with a mold cavity and at least one side opening (13) communicating with the vertical bottom hole and opened to the side face. The sliding member acceptor (20) includes degassing ports (21) communicating in an initial state with the side opening (13) of the sliding member and closed when the sliding member is slid in a direction against the elastic member by the flow tip portion of the molten material. The degassing structure is mounted in the molten material flow passage or in the cavity near the trailing end of the molten material flow passage, thereby to degas the mold inside.