Mold Hub Anticorrosion Coating for Reel Component
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Solution Overview
Problem
Conventional reel molds with gates at the center of the hub's bottom plate lead to weld lines on the outer peripheral face, causing corrosive gas concentration and corrosion, resulting in a rough surface that generates excessive abraded powder when recording tapes are wound, potentially leading to recording or playback defects like drop-out.
Innovation Solution
A mold design with a hub formation portion, flange, bottom plate, and anticorrosion coating applied to the outer peripheral face, where the gate is positioned inside the radial direction to prevent corrosive gas concentration and corrosion, reducing surface roughness and abraded powder generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the gate is disposed at the center portion of the bottom plate, then the injection molding process is simplified, but weld lines are formed on the outer peripheral face of the hub causing corrosion and surface roughness
Solution Approach 1:
The invention applies anticorrosion coating specifically to the wall face of the hub formation portion that forms the outer peripheral face of the hub, rather than coating the entire mold. This localized treatment addresses the corrosion problem at the weld line locations while maintaining manufacturing efficiency. The coating is applied only where corrosive gas concentrates, i.e., at portions formed by weld lines, thus resolving the contradiction between ease of manufacture and manufacturing precision.
2Device complexity
If the gate is disposed at the center portion of the bottom plate, then the mold structure is simplified, but corrosive gas concentrates at weld lines causing mold corrosion over time
Solution Approach 1:
The anticorrosion coating is applied specifically to the wall face of the hub formation portion that corresponds to the outer peripheral face of the hub, where weld lines form and corrosive gas concentrates. This localized protection approach maintains the simplicity of the mold structure while significantly improving mold durability by protecting only the vulnerable areas subjected to corrosive gas attack during injection molding.
Solution Approach 2:
The anticorrosion coating is applied in advance to the wall face of the hub formation portion before the corrosion problem occurs. This preliminary protective measure prevents corrosive gas from attacking the mold surface during the injection molding process, thereby extending mold life and maintaining reliability without requiring structural modifications to the mold.
3Object-generated harmful factors
If the outer peripheral face of the hub has a rough surface due to corrosion, then abraded powder is generated when recording tape slides, but this causes steps and creasing in the tape leading to drop-out
Solution Approach 1:
The anticorrosion coating is applied to the wall face of the hub formation portion that forms the outer peripheral face of the hub, creating a smooth, corrosion-resistant surface. This eliminates the rough surface that would otherwise generate excessive abraded powder during tape winding, thereby preventing tape creasing and ensuring reliable recording and playback quality.
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 anticorrosion coating reduces surface roughness and abraded powder generation, preventing creasing and drop-out during tape winding and playback, ensuring reliable recording and playback operations.
Implementation Method 1
an anticorrosion coating applied to a wall face of the hub formation portion that forms an outer peripheral face of the hub
Implementation Method 2
molded by a mold in which a gate as an injection inlet for melted resin material is disposed
Implementation Method 3
a free end portion of the recording tape is caused to make sliding-contact with the outer peripheral face of the hub, and the free end portion of the recording tape adheres to the outer peripheral face of the hub due to abraded powder that is generated
Implementation Method 4
the free end portion of the recording tape adheres to the outer peripheral face of the hub due to abraded powder that is generated
Data Source
AI summary
A mold for manufacturing a reel component member, the mold comprises a hub formation portion configured to form a circular tube shaped hub; a flange formation portion configured to form a flange integrally provided at one end portion of the hub; a bottom plate formation portion configured to form a bottom plate that is provided with a ring shaped reel gear at the one end portion or another end portion of the hub and that includes a plurality of hole portions provided at equal intervals on the reel gear; a gate that is disposed further to a radial direction inside than a wall face of the hub formation portion that is configured to form an inner peripheral face of the hub; and an anticorrosion coating that is applied to a wall face of the hub formation portion that is configured to form an outer peripheral face of the hub.