Angled Needle Valve Nozzle Thermal Expansion Alignment
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Solution Overview
Problem
In hot-runner injection molds, the differential thermal expansions due to components operating at different temperatures cause misalignment of the shut-off needle and sealing seat, especially when the actuating direction of the needle is not parallel to the flow channel, leading to operational issues.
Innovation Solution
The shut-off needle is aligned at an angle with the flow channel, and a guiding and sealing sleeve is used, which is seated in the cooler mold plate, while a heat conducting sleeve is employed to prevent cooling of the melt, ensuring the needle remains in contact with cooler regions and maintains alignment with the sealing seat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the shut-off needle is arranged at an angle to the flow channel, then the needle can be actuated effectively, but thermal expansion differences cause misalignment between the needle and sealing seat
Solution Approach 1:
The patent applies local quality by creating a temperature gradient within the nozzle structure itself. The flow channel is heated to prevent melt cooling, while the sealing seat remains at mold temperature. This localized temperature differentiation allows the needle to be angled for effective actuation while preventing thermal expansion-induced misalignment through controlled thermal zones.
Solution Approach 2:
The patent changes the temperature parameter distribution within the nozzle. By heating the flow channel region and keeping the sealing seat at lower temperature, the thermal expansion characteristics are modified to compensate for the angled needle arrangement, maintaining alignment despite the angular orientation.
2Temperature
If the flow channel is cooled to maintain temperature control, then the melt temperature is controlled, but the shut-off needle and sealing seat become misaligned due to differential thermal expansion
Solution Approach 1:
The patent implements local quality by differentiating temperature zones within the nozzle. The flow channel is heated to maintain melt temperature, while the sealing seat remains cooler. This localized temperature control allows effective melt temperature management while preventing differential thermal expansion that would cause misalignment.
Solution Approach 2:
The patent introduces an intermediary heating mechanism for the flow channel that separates the thermal control function from the sealing function. This intermediary heating system allows independent control of melt temperature without affecting the sealing seat temperature, thereby preventing misalignment.
3Device complexity
If the needle actuating direction is not parallel to the flow channel, then compact design is achieved, but thermal expansion causes displacement and misalignment
Solution Approach 1:
The patent uses local quality by creating distinct thermal zones within the compact nozzle structure. The flow channel is heated while the sealing seat remains cooler, allowing the needle to be angled for compact design while preventing thermal expansion-induced misalignment through localized temperature control.
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 configuration stabilizes the shut-off needle and prevents cooling of the melt, ensuring accurate sealing and efficient operation by maintaining axial alignment and preventing thermal expansion-induced displacements.
Implementation Method 1
a heat conducting sleeve (18) is employed to prevent cooling of the melt
Implementation Method 2
displacements are caused by different thermal expansions
Data Source
AI summary
A feature of a needle valve nozzle positioned in a hot-runner injection mould and actuated by means of an actuator, where the direction of actuation of the shut-off needle and that of the flow channel in the hot-runner nozzle differ from one another, is that, in the closed position, the shut-off needle (13), as distinct from the actuation device (12), is held in position, in the closed position, exclusively by the cooler mould plate (2) at at least two locations at a distance from one another.