Single Nozzle Valve Gate with Annular Piston for Thermal Management
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Solution Overview
Problem
Existing in-line valve gate pin actuation mechanisms in injection molding are complex, require significant force, and face thermal management challenges, leading to wear and inefficiencies, especially when handling highly filled and unfilled resins.
Innovation Solution
A compact, reliable in-line single nozzle valve gate apparatus with an annular dual-sided piston and mated annular cylinder bodies, utilizing a cross beam and air gaps to minimize thermal exposure and maximize force, while maintaining the piston seals in a lower thermal environment, allowing for efficient control of molten plastic flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pneumatic reciprocating pistons are used to move the valve gate pin, then the pin can be actuated between open and closed positions, but the mechanisms become complex and generate heat that affects seal performance
Solution Approach 1:
The invention extracts the thermal management function by separating the piston sealing system from the direct heat source. The piston is positioned in a cooler region of the mold cavity, removing it from the high-temperature zone near the nozzle, thereby reducing thermal exposure to the seals while maintaining actuation functionality.
Solution Approach 2:
The invention introduces air gaps as thermal intermediaries between the heat source (nozzle and flow paths) and the piston seals. These air gaps act as thermal barriers, reducing heat transfer to the sealing surfaces and allowing the pneumatic actuation mechanism to operate reliably without excessive thermal exposure.
2Volume of moving object
If small pistons with O-rings in direct contact with heated flow steel are used, then the actuating mechanism is compact, but the seals are subjected to deleterious heat
Solution Approach 1:
The invention removes the piston sealing system from direct contact with heated surfaces. By positioning the piston in a cooler region and using air gaps as thermal barriers, the seals are extracted from the high-temperature environment, eliminating the harmful thermal effect while maintaining compact piston dimensions.
3Ease of operation
If the actuating mechanism is placed within the plate arrangement near the in-line flow path, then the valve gate can be controlled, but the architecture becomes complex and heat management becomes difficult
Solution Approach 1:
The invention extracts the actuating mechanism from the complex plate arrangement and positions it in a simpler, cooler region of the mold cavity. This relocation simplifies the overall architecture by reducing the number of interacting components near the flow path while maintaining effective valve gate control.
4Reliability
If considerable force is applied to the valve gate pin for proper control, then the gate can be reliably actuated, but the mechanism requires high clamping force
Solution Approach 1:
The invention uses pneumatic pressure to actuate the valve gate pin, replacing direct mechanical force application. The pneumatic system delivers controlled force through the piston, providing reliable gate actuation while reducing the overall clamping force requirements compared to direct mechanical actuation 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
The solution provides high pin force, reduces wear, and minimizes thermal damage, enabling efficient processing of various resin types with improved reliability and ease of nozzle changes, while maintaining a compact design.
Implementation Method 1
an annular dual sided piston and mated annular cylinder bodies... When mated, the inner surfaces of the upper and lower cylinder bodies define a central through-hole... Extending through the annular slot is a cross beam that forms a bridge between the inner surfaces of the piston
Implementation Method 2
utilizing a cross beam and air gaps to minimize thermal exposure and maximize force, while maintaining the piston seals in a lower thermal environment
Data Source
AI summary
An in-line single nozzle valve gate apparatus for injection molding comprises upper and lower rnatable annular cylinder bodies that house an annular dual sided piston having opposed pressure bearing upper and lower surfaces. The piston has a cross beam to which a valve gate pin is attached for movement therewith. The valve gate pin passes through a sprue bushing flow path to selectively open and close a part cavity gate. An interface is provided to receive molten plastic from the injection machine nozzle and pass it into the sprue bushing flow path. The cylinder bodies reside largely outside of the mold plate architecture to lessen thermal damage too piston seals.