In-Mold Foam Article with Segmented Insert for Warping Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In-mold foam molded articles with embedded insert members, such as metal wires, experience warping due to differing shrinkage rates between the foam body and the insert member, leading to dimensional inaccuracies and attachment issues in vehicle components like seat cushions.
Innovation Solution
Incorporating a movement facilitating structure within the foam body, featuring elongated connecting portions and movement resisting portions, allows relative movement between the insert member and the foam body during shrinkage and expansion, preventing warping by enabling smooth shape recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an insert member is embedded in a foam body by insert molding, then the structural strength and shape stabilization are improved, but the differential shrinkage between the foam body and insert member causes warping and dimensional inaccuracy
Solution Approach 1:
The foam body is segmented into multiple independent foam portions by dividing spaces, allowing each portion to shrink independently during the foaming process. This segmentation prevents the accumulation of shrinkage stresses that would otherwise cause warping of the entire molded article, while still maintaining overall structural integrity through the insert member.
Solution Approach 2:
The insert member is designed with varying cross-sectional areas along its length, creating local quality differences. portions with larger cross-sectional areas provide greater shape stabilization in regions prone to warping, while smaller cross-sectional areas reduce restraint in regions where flexibility is needed. This localized adjustment optimizes the balance between structural strength and warping prevention.
2Stability of the object's composition
If the foam body is completely restrained by the insert member during shrinkage, then the shape stability is improved, but the foam body cannot return to its original shape and warping occurs
Solution Approach 1:
By dividing the foam body into multiple independent portions, the insert member can provide shape stability to each portion without completely restraining the overall shrinkage movement. Each foam portion can shrink independently toward its own center, preventing the accumulation of restraining stresses that would cause warping.
Solution Approach 2:
The insert member's cross-sectional area is varied along its length to create different degrees of restraint in different regions. This parameter change allows the insert member to provide adequate shape stability in critical areas while permitting controlled shrinkage in other areas, preventing warping.
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 warping and improves dimensional accuracy of in-mold foam molded articles, ensuring proper attachment and reducing manufacturing rejections by allowing the foam body to shrink and return to its original shape without distortion.
Implementation Method 1
the shrinkage of the in-mold foam molded article after the release from the mold
Implementation Method 2
the vapor in the cells is cooled after in-mold foam molding and release from the mold, and then will return to its original size when the outside air is introduced into the cells
Data Source
Figure 1~2
Figure 3(a)~4
Figure 5(a)~5(d)
AI summary
Provided are an in-mold foam molded article that can be formed with improved dimensional accuracy while warping is suppressed, a method for forming such an article, and a mold for use in forming such an article. The in-mold foam molded article 1 includes a foam body 2 including olefin-based resin pre-expanded beads; and an insert member 3 including an elongated connecting portion 6 and movement resisting portions 7 provided apart from one another in the connecting portion 6, the insert member 3 being subjected to insert molding upon in-mold foam molding using the olefin-based resin pre-expanded beads. A movement facilitating structure is provided to facilitate relative movement between the insert member 3 and the foam body 2 during shrinkage of the in-mold foam molded article 1 released from the mold, and has a dividing space 5 that is formed along a direction crossing the connecting portion 6 to divide the foam body 2 into two divided foam parts 4.