Composite Corner Molding via Two-Step Thickness Reduction
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Solution Overview
Problem
Existing methods for molding composite materials with curved corner parts often result in imperfect molding due to thickness reduction leading to surplus material and wrinkles, as the outside circumference is shortened, making it difficult to suppress wrinkle formation and achieve proper densification.
Innovation Solution
A two-step molding process where the laminate's thickness is reduced from the outside to the inside in the first shaping step and from the inside to the outside in the second shaping step, using a male and female mold respectively, to manage the curvature and surplus material effectively, thereby preventing wrinkles and ensuring densification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pushing pressure is applied from the outside of the reinforced fiber laminate to the shoulder, then the thickness of the shoulder is reduced, but the outside circumference of the corner part is shortened generating surplus material and wrinkles
Solution Approach 1:
The molding process is divided into two distinct shaping steps: first shaping to reduce thickness from outside toward inside, and second shaping to reduce thickness from inside toward outside. This segmentation allows independent control of thickness reduction direction and magnitude, preventing surplus material generation and wrinkle formation while achieving uniform thickness distribution in the corner part.
Solution Approach 2:
The first shaping step performs preliminary thickness reduction from the outside toward the inside before the second shaping step. This preliminary action prepares the laminate by creating controlled surplus material distribution that will be evenly worked out in the second shaping step, preventing wrinkle formation during final molding.
2Manufacturing precision
If the outside circumference of the corner part is shortened by thickness reduction, then densification is improved, but surplus material is generated causing imperfect molding
Solution Approach 1:
The densification process is segmented into two shaping steps with different thickness reduction directions. The first shaping reduces thickness from outside toward inside to achieve initial densification, while the second shaping reduces thickness from inside toward outside to eliminate surplus material. This segmentation ensures both densification and molding quality are achieved without compromise.
Solution Approach 2:
The invention changes the parameter of thickness reduction direction between two shaping steps. By switching from outside-to-inside reduction in the first step to inside-to-outside reduction in the second step, the process optimizes both densification and surplus material elimination, achieving high molding quality without imperfect defects.
3Ease of manufacture
If a single shaping step is used, then the process is simple, but uniform thickness reduction and wrinkle suppression cannot be achieved
Solution Approach 1:
The molding process is segmented into two shaping steps, each with a specific thickness reduction direction. The first shaping step reduces thickness from outside toward inside, and the second shaping step reduces thickness from inside toward outside. This segmentation achieves uniform thickness reduction and wrinkle suppression that cannot be accomplished in a single step, while maintaining reasonable process complexity.
Solution Approach 2:
The invention introduces dynamic adjustment of the thickness reduction direction between two shaping steps. By making the process directional and adaptive rather than static, uniform thickness reduction is achieved across different regions of the laminate, preventing wrinkle formation while maintaining manufacturability.
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 effectively suppresses the generation of wrinkles and ensures proper densification of the composite material's corner parts, maintaining uniform fiber content and preventing imperfect molding, with a densification of at least 7% achievable while keeping the fiber content difference within 3% of the linear and corner parts.
Implementation Method 1
shaping a laminate having the corner part curved at a first bending angle and fiber sheets laminated such that a plate thickness of the laminate is reduced from an outside toward an inside of the corner part
Data Source
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AI summary
A method for molding composite material 1 such as a spar 10 formed with a curved corner part 10c is provided with: a first shaping step S1 of shaping a laminate 3 so that the board thickness of the laminate 3 is reduced from the outside of the corner part 10c toward the inside thereof, the laminate 3 having the corner part 10c curved at a first bending angle ϕ2 and comprising fiber sheets laminated to each other; and a second shaping step S2 of curving the corner part 10c of the laminate 3 to form a second bending angle ϕ1 smaller than the first bending angle, and shaping the laminate 3 so that the board thickness of the laminate 3 is reduced from the inside of the corner part 10c toward the outside thereof.