Reel Flange Deformation Control via Inverted Gate Injection
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Solution Overview
Problem
Conventional recording tape reels experience deformation and surface runout issues due to differing cooling times of the hub and lower flange, leading to increased manufacturing costs and processes, and potential deformation under tight winding.
Innovation Solution
A reel design with a cylindrical hub, an upper flange integrally formed with the hub, and a lower flange with a bottom wall that is welded to the hub, allowing for insert molding of the reel plate and even resin material flow, reducing surface runout and deformation without increasing manufacturing complexity or costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the gate is positioned at the bottom wall portion of the hub and resin material flows into the hub side first, then the hub can be formed with sufficient material, but shrinkage and deformation occur due to different cooling times of the hub and lower flange
Solution Approach 1:
The gate position is inverted from the conventional bottom wall position to the peripheral edge position of the lower flange. This reversal changes the resin flow direction so that material fills the lower flange first, then flows to the hub, ensuring both parts cool simultaneously and preventing deformation and surface runout.
2Manufacturing precision
If the lower flange is adhered to the hub after integral formation, then surface runout in the upper flange can be suppressed, but the number of processes and manufacturing costs increase due to subsequent reel plate fixation
Solution Approach 1:
The lower flange and hub are merged into a single integrally formed component through simultaneous molding. The gate is positioned at the lower flange's peripheral edge, allowing resin to fill both the lower flange and hub in one injection process, eliminating the need for separate adhesion and reel plate fixation steps.
3Strength
If the hub is made thicker than the lower flange to ensure structural integrity, then the hub can support tight winding, but the cooling time difference causes lower flange deformation
Solution Approach 1:
The resin flow path is designed to preliminarily fill the lower flange before filling the hub. By positioning the gate at the lower flange's peripheral edge, the lower flange receives material first and begins cooling earlier, compensating for the hub's greater thickness and ensuring both parts cool simultaneously without deformation.
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 design effectively suppresses flange deformation and surface runout, ensures coaxial alignment of the reel gear and hub, and improves the winding form of the recording tape by expelling air through depressions, all while maintaining cost-effectiveness.
Implementation Method 1
a lower flange that includes a bottom wall to which a reel plate is fixed, and that is welded to the other end portion of the hub
Implementation Method 2
a gate for injecting resin material is positioned so as to correspond to a position of the bottom wall portion of the hub. Accordingly, the resin material injected through the gate flows once into the 'hub side' of the metal mold, and after that, flows to the 'lower flange side' of the metal mold
Implementation Method 3
there is a problem in that shrinkage and the like occur because the cooling times of the hub and lower flange differ
Data Source
AI summary
A reel is provided including a cylindrical hub onto which a recording tape is wound; an upper flange that is integrally provided at the hub, and that extends from one end portion of the hub; and a lower flange that includes a bottom wall to which a reel plate is fixed, and that is welded to the other end portion of the hub, in order that deformations and surface runout of the flanges can be suppressed without increasing number of process and/or manufacturing costs.