Fiber-Reinforced Plastic Molding Grain Core
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Solution Overview
Problem
In the molding of fiber-reinforced plastics with closed or open cross-sections, existing methods face challenges such as void formation, deformation, and dimensional inaccuracies due to pressure and heat, leading to defects like wrinkles and buckled shapes, and require high-cost molds that need frequent changes for shape variations.
Innovation Solution
A method using a core with a grain group in a flexible bag, where the prepreg is wrapped around the core and subjected to compression molding with a mold interval holding mechanism to maintain constant distance between molds, allowing for uniform pressure application without gas or liquid, and using a deformable deforming mold for open cross-sections to achieve precise shaping and reduce mold costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a vacuum-packaged powder grain group core is used, then the core can be formed into a predetermined shape, but voids form between the core and prepreg during molding, causing wrinkles and deformation
Solution Approach 1:
The core is constructed with a flexible bag containing a grain group, allowing the bag to conform to the mold cavity shape while maintaining internal pressure to eliminate voids between the core and prepreg during molding
Solution Approach 2:
Gas is introduced into the flexible bag to inflate and maintain internal pressure, ensuring the core remains in close contact with the prepreg throughout the molding process, preventing void formation and deformation
2Shape
If the upper mold moves upward due to core deformation, then the core can be pressed and deformed, but the mold interval increases causing dimensional inaccuracies
Solution Approach 1:
The mold interval holding means is activated before and during the core deformation process to pre-establish and maintain the correct mold interval, preventing upward movement of the upper mold and ensuring dimensional accuracy of the molded article
Solution Approach 2:
The mold interval holding means acts as an intermediary mechanism between the upper and lower molds, controlling and maintaining the interval between them during the deformation process to prevent dimensional inaccuracies
3Manufacturing precision
If high-cost molds are used for closed cross-section molding, then dimensional accuracy can be maintained, but mold changes are required for shape variations increasing complexity
Solution Approach 1:
The molding system achieves multi-functionality by combining a single mold with a deformable core that can be inflated to different shapes, allowing the same mold to produce various cross-sectional shapes without requiring multiple specialized molds
4Manufacturing precision
If gas or liquid is introduced to increase core internal pressure, then voids can be eliminated, but the system becomes more complex requiring additional equipment
Solution Approach 1:
The flexible bag itself serves as the pressure containment structure, utilizing the bag's elasticity and the trapped gas to automatically maintain internal pressure and eliminate voids without requiring complex external pressurization equipment
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
This approach ensures high-dimensional accuracy, prevents voids and deformation, and allows for cost-effective production with reduced mold changes, maintaining product quality and reducing manufacturing costs by enabling uniform pressure distribution and precise shaping of fiber-reinforced plastic products.
Implementation Method 1
pressing a part of outer surfaces of the core, via the prepreg or not via the prepreg, to increase internal pressure of the core and deform the core by pressing means which comes into the cavity between the upper mold and the lower mold
Data Source
AI summary
A method for molding fiber-reinforced plastic. A core is formed in a desired shape by accommodating, in a flexible bag, a grain group containing plurality of grains. The core is placed inside a prepreg containing resin and fibers, and the prepreg, in which the core is housed is placed in a molding die and compression molded. When doing so, the grain group contains first and second grains (a,b) that satisfy the equation (1). (1) 1.1≤(Da/Db)≤2.0 In the equation Da is the grain diameter of the grains (a), and Db is the grain diameter of the grain (b). When using a molding die to mold a molded article having a cavity, the above mentioned molding method enables an increase in the internal pressure of the core in order to change the peripheral surface area of the core, without using a pressurized gas and/or pressurized liquid.