Foam Molding Suppressing Balloon Bubbles via Cell Diameter Gradient
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Solution Overview
Problem
In foam molded articles with plate-shaped parts connected to a tube body, the increased foaming magnification during molding leads to air bubbles being crushed, causing them to move towards the tube body and form balloon-shaped air bubbles, which degrade fluid flow efficiency and cause abnormal sounds and vibrations.
Innovation Solution
A foam molded article design where the connection inner surface on the tube body is optimized to prevent air bubble collection, with a shortest distance between connection points of 30 cm or less, and a molding method that sets the average cell diameter on the inner surface to be 1.2 times greater than on the outer surface, maintaining the foamed resin in a molten state for a shorter applying time to prevent balloon-shaped air bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the foaming magnification is increased to improve thermal insulation and reduce weight, then thermal insulation property and weight reduction are improved, but air bubbles are crushed and move toward the tube body forming balloon-shaped air bubbles that degrade fluid flow efficiency
Solution Approach 1:
The patent applies different cell diameter characteristics to different regions of the foam molded article. Specifically, the average cell diameter on the inner surface side is made 1.2 times or more greater than on the outer surface side, creating local quality differences that prevent air bubble migration while maintaining overall foaming magnification for weight reduction and thermal insulation.
Solution Approach 2:
The patent changes the physical parameters of the foam structure by controlling the cell diameter distribution during molding. By adjusting the applying time of the pressing force and controlling the foaming process, the patent achieves a specific cell diameter ratio (1.2 or more) between inner and outer surfaces, which prevents balloon-shaped air bubble formation while maintaining high foaming magnification.
2Strength
If the plate-shaped part is strongly pressed during mold clamping to improve structural strength, then structural strength is improved, but air bubbles move toward the tube body and form balloon-shaped air bubbles
Solution Approach 1:
The patent creates local quality differences in the foam structure by making the average cell diameter on the inner surface side 1.2 times or more greater than on the outer surface side. This local structural difference prevents air bubbles from migrating toward the tube body during pressing, while still allowing the plate-shaped part to achieve the required structural strength through controlled foaming.
Solution Approach 2:
The patent applies a pressing force during the molding process to pre-compress the foamed resin before the air bubbles can migrate and form balloon-shaped defects. By controlling the applying time of this pressing force, the patent prevents air bubble movement while ensuring proper structural strength development in the plate-shaped part.
3Manufacturing precision
If the applying time of pressing force is extended to ensure complete molding, then molding completeness is improved, but air bubbles have more time to move and form balloon-shaped air bubbles
Solution Approach 1:
The patent applies a pressing force during the molding process to pre-compress the foamed resin before air bubbles can migrate and form balloon-shaped defects. By controlling the applying time of this pressing force, the patent achieves complete molding while preventing air bubble movement that would create harmful defects.
Solution Approach 2:
The patent uses a controlled pressing force that acts quickly during the critical foaming period to prevent air bubble migration. By rushing through the critical molding phase with appropriate pressing force application, the patent achieves complete molding without allowing sufficient time for balloon-shaped air bubbles to form.
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 effectively suppresses the generation of balloon-shaped air bubbles, maintaining the inner surface softness for easy fitting while ensuring the outer surface rigidity, thus enhancing fluid flow efficiency and reducing vibrations.
Implementation Method 1
a pressing force to press the foamed resin against the split metallic molds
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Generation of a balloon-shaped air bubble is suppressed. A foam molded article according to a mode of the present disclosure is characterized in that in a situation of being divided into two equal parts in the thickness direction T of the foam molded article, the average cell diameter α1 in the thickness direction T on the inner surface side A of the foam molded article is 1.2 times ((α1/β1)=1.2) or greater of the average cell diameter β1 in the thickness direction T on the outer surface side B of the foam molded article and that the surface roughness Sm of the inner surface of the foam molded article is 1000 µm or greater.