Injection Mold Pin Light Guide Gap-Free Fixation
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Solution Overview
Problem
Conventional ejector pins with bundle fibers in injection molds face issues with adhesive strength due to uneven surfaces, leading to gaps and inadequate fixation, which results in exposure of heat-resistant resin to molten resin pressure and potential erosion, compromising measurement accuracy for flow speed and temperature.
Innovation Solution
A pin design featuring a bundle fiber with a cone-shaped caulked portion that matches the tapered shape of the inner sleeve, eliminating gaps and using a heat-resistant resin layer between uneven portions of the sleeves to ensure secure fixation and resistance to resin pressure, along with a shoulder portion and nut engagement to prevent movement under pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a bundle fiber is used to increase light emitting/receiving amount, then measurement capability is improved, but the uneven surface creates clearance and reduces adhesive strength
Solution Approach 1:
The inner sleeve is pre-formed with a tapered portion that matches the cone-shaped caulked portion of the bundle sleeve. This preliminary geometric preparation ensures that when the bundle sleeve is inserted, the tapered surfaces guide the assembly and eliminate clearance between the components, providing a secure fit before any adhesive is applied.
Solution Approach 2:
The heat resistant resin is applied specifically to the uneven portions of the bundle fiber surface and the corresponding inner sleeve surface. This localized application ensures that the resin fills the gaps created by the uneven bundle fiber surface, providing adhesive strength precisely where needed without requiring the entire surface to be smooth.
2Strength
If heat resistant resin is used to fix the bundle fiber, then fixation is achieved, but the resin is exposed to molten resin pressure and may be eroded
Solution Approach 1:
The bundle sleeve is inserted into the inner sleeve, creating a nested structure. The tapered portion of the inner sleeve works in conjunction with the cone-shaped caulked portion of the bundle sleeve to create a tight fit, nesting the bundle fiber assembly within the sleeve structure and protecting the heat resistant resin from direct exposure to molten resin pressure.
Solution Approach 2:
The inner sleeve is pre-formed with a tapered portion that matches the bundle sleeve's caulked portion. This preliminary geometric design ensures that when assembled, the interfaces are tightly fitted, preventing exposure of the heat resistant resin to molten resin pressure before the resin curing process completes.
3Ease of manufacture
If a single line optical fiber is used, then installation is simple, but light transmission amount is insufficient for flow speed measurement
Solution Approach 1:
Multiple optical fibers are merged into a single bundle fiber assembly. The bundle fiber combines multiple individual optical fibers into one unified structure that maintains the simplicity of single-fiber installation while providing the cumulative light transmission capability necessary for accurate flow speed measurement.
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 ensures a secure and gap-free fixation of the bundle fiber, preventing resin exposure and erosion, maintaining measurement accuracy and reliability for flow speed and temperature monitoring.
Implementation Method 1
When molten resin is injected into the cavity 15, infrared rays are emitted from the molten resin. The infrared rays are transmitted to the light receiving portion 14 through the optical fiber Fs
Implementation Method 2
The infrared rays are transmitted to the light receiving portion 14 through the optical fiber Fs
Implementation Method 3
An optical fiber Fs of a single line (single strand) is inserted into the hollow portion and fixed to the spacer 12 by heat resistant resin (heat resistant adhesive) 13
Implementation Method 4
a portion of the hollow portion of the inner sleeve which is brought into contact with the cone-shaped caulked portion of the bundle sleeve has a tapered shape that coincides with the shape of the portion of the bundle sleeve
Data Source
AI summary
A pin having a light guide for an injection mold includes an outer sleeve having a hollow portion, an inner sleeve fixed to the hollow portion of the outer sleeve, a bundle sleeve fixed to a hollow portion of the inner sleeve, a bundle fiber fixed to a hollow portion of the bundle sleeve. A leading end portion of the bundle sleeve has a substantially cone-shaped caulked portion. A portion of the hollow portion of the inner sleeve which is brought into contact with the cone-shaped caulked portion of the bundle sleeve has a tapered shape that coincides with the shape of the portion of the bundle sleeve. A shoulder portion is formed at a rear end portion of the hollow portion of the outer sleeve and a rear end of the inner sleeve is engage with the shoulder portion.