Torque-Limited Injection Mold Core Positioning
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Solution Overview
Problem
The existing injection tooling for wax models in the lost wax casting process often applies excessive force to ceramic cores, risking deformation, displacement, or damage, which can lead to parts not meeting specifications.
Innovation Solution
A one-piece injection tool with torque limiting means between the tightening head and threaded parts of the pressure screws, allowing for controlled core positioning without excessive force, ensuring the core remains stable and undamaged during molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pressure screw is tightened to hold the core securely in place, then the core positioning stability is improved, but the core may be deformed, displaced, or damaged due to excessive clamping force
Solution Approach 1:
The invention changes the parameter of clamping force by introducing a torque limiting mechanism that caps the maximum torque at a predetermined safe value. This ensures the core is held securely without exceeding the force threshold that would cause deformation or damage, thus resolving the contradiction between positioning stability and core integrity.
Solution Approach 2:
The torque limiting means acts as an intermediary element between the pressure screw and the core. It transmits clamping torque up to a safe predetermined value and then decouples to prevent further torque transmission, thereby protecting the core from excessive force while maintaining adequate positioning stability.
2Device complexity
If a simple pressure screw mechanism is used, then the device complexity is reduced, but it cannot prevent excessive force application to the core
Solution Approach 1:
A torque limiting means is introduced as an intermediary component between the simple pressure screw mechanism and the core. This addition provides force protection without significantly complicating the overall mechanism, as the torque limiter can be integrated into the existing screw structure while maintaining operational simplicity.
Solution Approach 2:
The torque limiting mechanism is designed to automatically decouple when the predetermined torque value is reached, without requiring external intervention or complex control systems. This self-regulating feature protects the core from excessive force while keeping the device simple and easy 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
The tool effectively maintains core position and prevents deformation or displacement, ensuring the molded parts meet specifications while allowing for easy demolding and reducing the risk of core damage.
Implementation Method 1
torque limiting means, disposed between a clamping head and a threaded part of the pressure screw, and designed to transmit the clamping torque from the head to the threaded part when said torque is less than a determined value and to decouple the head and the threaded part when said torque is greater than the determined value
Data Source
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Figure 3~4
AI summary
The invention relates to a tool for injection-moulding a part, which comprises two cavity retainer blocks (4) in which cavities (6) are arranged, the shape of which after stacking the cavity retainer blocks corresponds to that of the part to be moulded (25). At least one of the cavity retainer blocks (4) is provided with a means for positioning a core, comprising at least one bearing surface intended for providing a bearing for the core, and at least one set screw (13, 14), screwed into a threaded passage of the cavity retainer block (4) and intended for holding the core in position against the bearing surface (8, 9). The tool comprises a means for limiting the force applied to the core by the set screw (13, 14).