Tape Reel Mold Bulging Surface for Roundness
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Solution Overview
Problem
Existing mold technologies fail to accurately form a cylindrical portion of tape reels into a shape close to a perfect circle, leading to irregularities that affect the transport speed and data integrity of recording tapes.
Innovation Solution
A mold design featuring a tubular surface with specific projecting portions that bulge radially outward, allowing for equal contraction and forming a cylindrical portion with a roundness of 20 μm or less, ensuring a shape close to a perfect circle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional mold is used to form the cylindrical portion of the tape reel, then the manufacturing process is simple, but the roundness of the cylindrical portion deteriorates (cannot achieve 20 μm or less)
Solution Approach 1:
The mold applies local quality by creating specific bulging portions only in the first portions of the tubular surface, while keeping other areas different. This localized modification allows the resin to contract uniformly during cooling, achieving high roundness (20 μm or less) without making the entire mold structure complex. The bulging portions are strategically positioned to compensate for contraction variations in specific regions.
Solution Approach 2:
The mold utilizes parameter changes by intentionally varying the shape parameters of the tubular surface. The first portions are designed with a bulging shape (different curvature radius) compared to the second portions. This parameter variation compensates for non-uniform contraction of the resin during cooling, ensuring the final cylindrical portion achieves the required roundness without excessive mold complexity.
2Reliability
If the cylindrical portion has poor roundness, then the manufacturing process is simpler, but the transport speed stability of recording tapes deteriorates
Solution Approach 1:
The mold implements preliminary action by pre-shaping the tubular surface with bulging portions before the resin is injected. This pre-formed geometry compensates for the expected non-uniform contraction that will occur during cooling. As a result, the cylindrical portion of the tape reel achieves high roundness (20 μm or less) automatically during the molding process, ensuring stable transport speed without requiring additional post-processing or complex control mechanisms.
3Measurement precision
If the cylindrical portion has poor roundness, then the manufacturing process is simpler, but data reading and writing accuracy deteriorates
Solution Approach 1:
The mold applies local quality by creating specific bulging portions only in the first portions of the tubular surface, while keeping other areas different. This localized modification allows the resin to contract uniformly during cooling, achieving high roundness (20 μm or less) without making the entire mold structure complex. The bulging portions are strategically positioned to compensate for contraction variations in specific regions.
Solution Approach 2:
The mold utilizes parameter changes by intentionally varying the shape parameters of the tubular surface. The first portions are designed with a bulging shape (different curvature radius) compared to the second portions. This parameter variation compensates for non-uniform contraction of the resin during cooling, ensuring the final cylindrical portion achieves the required roundness without excessive mold complexity.
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 achieves a tape reel with a roundness of 20 μm or less, stabilizing the transport speed of recording tapes and reducing errors in data reading and writing, thereby enhancing the performance of tape cartridges.
Implementation Method 1
the first portion has a shape that bulges toward a radially outer side of the bottom surface than a second portion corresponding to the projecting portion
Data Source
AI summary
There is provided a mold for molding a tape reel that is made of a resin and that includes a cylindrical portion, a bottom portion formed on a proximal end side of the cylindrical portion, and a plurality of through holes penetrating the bottom portion and arranged in a peripheral direction of the cylindrical portion, the mold including: a bottom surface that is used to form the bottom portion; a tubular surface that is used to form the cylindrical portion; and a plurality of projecting portions that protrude from the bottom surface and are used to form the plurality of through holes, respectively, in which, in the tubular surface, a first portion corresponding to a portion between the projecting portions adjacent to each other in the peripheral direction, among the plurality of projecting portions, has a shape that bulges toward a radially outer side of the bottom surface than a second portion corresponding to the projecting portion.