Turntable Resin Sinkage Prevention via Lower Gate Injection
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Solution Overview
Problem
Conventional storage disk turntables face issues with resin sinkage in the upper portion of the central resin member, which affects the accuracy and reliability of the disk guide portion, leading to potential inaccuracies in centering the storage disk.
Innovation Solution
A turntable design featuring a plate member made of ferromagnetic material with a central resin member formed by injection-molding, where the resin is injected through a gate positioned on the lower side to prevent resin sinkage by ensuring uniform curing and accurate formation of the disk guide portion, and the use of gate cut portions and recess portions to enhance the structural integrity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If resin is injected from the upper side to form the central resin member, then the injection process is simple, but resin sinkage occurs in the upper portion affecting the accuracy of the disk guide portion
Solution Approach 1:
The patent inverts the conventional injection direction by injecting resin from the lower side (opposite to the upper surface) through a gate formed in the lower mold. This inversion prevents resin sinkage in the upper portion where the disk guide portion is formed, thereby maintaining manufacturing precision while keeping the process simple.
Solution Approach 2:
The patent introduces a vertical dimension consideration by forming the gate in the lower mold and injecting resin upward through the thickness direction of the plate member. This dimensional approach allows the resin to fill from the bottom, preventing sinkage at the critical upper surface where the disk guide portion is located.
2Manufacturing precision
If gate recess portions are formed in the central resin member, then resin sinkage is prevented, but the structure becomes more complex
Solution Approach 1:
The patent extracts the gate recess portions from the final product structure by designing them as temporary features only present during molding. The gate recess portions are formed in the mold cavity and removed after injection, leaving no permanent complex structure in the central resin member while still preventing resin sinkage during the molding process.
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 effectively prevents resin sinkage, ensuring increased accuracy and reliability of the disk guide portion, allowing for precise centering of storage disks like Blu-ray disks, while also reducing the risk of resin burr formation and wear on mold components.
Implementation Method 1
forming a central resin member at the center of the plate member by injecting a resin into the cavity from a gate provided in one of the movable mold and the fixed mold
Data Source
AI summary
A turntable for storage disk drive apparatuses includes a plate member made of a ferromagnetic material and a central resin member arranged at the center of the plate member and formed by injection-molding a resin. The central resin member includes a disk guide portion provided on an upper surface thereof to guide a central hole of a disk and a plurality of gate recess portions indented upwards from a lower surface of the central resin member. The gate recess portions include ceiling surfaces positioned higher than the plate member. The ceiling surfaces include a plurality of gate cut portions formed in an injection molding process.