Injection-Molded Pipe Member With Ribs for Uniform Resin Flow
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Solution Overview
Problem
Conventional methods for manufacturing pipe members that supply liquid fillers to brushes result in bent pipe portions due to uneven resin flow and excessive pressure, leading to defects such as curvature and core pin damage.
Innovation Solution
The pipe member features a holder portion with discharge holes and a pipe portion with ribs on its outer periphery, formed through injection molding with resin injecting ports positioned on the surface except the pipe portion and ribs, ensuring uniform resin flow and reduced pressure application, preventing bending and thickness shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the pipe portion is made thin and long to reduce brush outer diameter, then the brush can be smaller, but the pipe portion becomes hard to fill uniformly with molten resin causing bending
Solution Approach 1:
The pipe portion is divided into multiple sections by adding ribs at regular intervals. These ribs create multiple flow paths for the molten resin, allowing uniform filling throughout the long pipe portion and preventing bending by distributing the flow pressure evenly across different segments.
Solution Approach 2:
Ribs are added at specific locations along the pipe portion to create localized structural reinforcements and flow distribution points. This local modification ensures uniform resin flow without requiring the entire pipe to be thicker, maintaining the thin-walled design while preventing bending.
2Manufacturing precision
If higher pressure is applied to fill molten resin uniformly in the pipe portion, then uniform filling is achieved, but excessive load is applied to the core pin causing bending and die breakdown
Solution Approach 1:
The ribs divide the pipe portion into multiple flow paths, which distributes the injection pressure across multiple channels rather than concentrating it through a single long core pin. This segmentation reduces the load on the core pin while maintaining uniform resin filling.
Solution Approach 2:
The ribs create localized flow distribution points that reduce the overall pressure requirement for uniform filling. By creating multiple entry points for resin flow along the pipe portion, the system achieves uniform filling at lower pressure, preventing core pin bending and die breakdown.
3Ease of manufacture
If the pipe portion is made thicker to ease resin flow, then resin flow is improved, but thickness shrink marks and voids are generated due to large thickness difference
Solution Approach 1:
Instead of increasing the overall pipe thickness, ribs are added locally at specific positions. This creates a thin-walled pipe with localized reinforcements that ease resin flow at the rib locations without creating large thickness differences throughout the entire pipe, thus preventing shrink marks and voids.
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 prevents pipe bending and thickness shrinkage, enhances pipe rigidity, and avoids core pin damage and die breakage, resulting in a high-quality pipe member with improved manufacturing efficiency.
Implementation Method 1
the molten resin from the holder portion is hard to uniformly flow toward the leading end of the cylinder portion of the pipe portion
Implementation Method 2
a difference is generated in a cooling time between the cylindrical portion through which the resin first flows and the cylinder portion through which the resin flows later, so that the pipe portion is curved after being cooled and solidified
Data Source
AI summary
To provide an injection molded pipe member having a high quality, the pipe member is integrally provided with a holder portion (20), a pipe portion (30) and ribs (40) arranged in an outer periphery of the pipe portion (30) at a uniform interval in peripheral direction, protruding in radial direction and reaching the holder portion (20) from a middle of the pipe portion (30), and has a resin injecting position (20f) in a surface of a portion except the pipe portion (30) and the ribs (40), so that molten resin flows quickly through the forming space uniformly in peripheral direction without being deflected when injection molding, thereby bend of the pipe portion (30), thickness shrink, and forming die breakage is prevented.