Fiber Sheet Lamination Geometry for Wrinkle-Free Bending
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Solution Overview
Problem
Existing methods face challenges in suppressing wrinkles during the bending of fiber sheet laminates and require longer lamination times due to limitations in laminating fiber sheets at specific angles and differences in peripheral length, especially in complex cross-sectional shapes.
Innovation Solution
A forming method that uses a lamination device with a forming die having angles closer to a flat plane than the final bent angle, allowing wider tow or tape lamination and reducing interlayer slip, combined with adjustable interlayer adhesive forces to enhance adherence and reduce wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fiber sheets are laminated using a conventional lamination device with fixed discharge direction, then the lamination process is simple, but the fiber sheets cannot be laminated at various angles required for complex cross-sectional shapes
Solution Approach 1:
The lamination device is configured to be movable and adjustable, allowing the discharge direction of fiber sheets to be changed dynamically. This enables lamination at various angles (including 45 degrees on inner surfaces of L-shaped sections and on recess surfaces) without requiring multiple fixed devices, thus improving adaptability while controlling complexity
Solution Approach 2:
The invention adds angular dimensionality to the lamination process by enabling fiber sheet discharge in multiple directions. The lamination device can orient fibers at different angles relative to the longitudinal direction, transforming a one-dimensional lamination process into a multi-dimensional one that accommodates complex geometries
2Manufacturing precision
If a narrow tow or tape is used to laminate curved protrusion shapes to prevent wrinkles, then wrinkle occurrence is suppressed, but the lamination time becomes longer
Solution Approach 1:
The invention changes the geometric parameters of the forming die, specifically setting the angle between forming surfaces to be larger than the final bent angle (e.g., 180 degrees or more for 90-degree bends). This parameter adjustment allows wider tows to be laminated without causing wrinkles during subsequent bending, thus improving productivity while maintaining manufacturing precision
Solution Approach 2:
The forming die is designed in advance with angles larger than the final bent angle, preparing the structure beforehand to accommodate wider tows. This preliminary configuration prevents wrinkle formation during the bending process, eliminating the need to use narrow tows and thereby reducing lamination time
3Shape
If fiber sheet laminate is bent to have an R-surface to match the final shape, then the formed article achieves the correct geometry, but wrinkles occur due to excess fibers from peripheral length difference
Solution Approach 1:
The forming die is designed in advance with angles larger than the final bent angle (e.g., 180 degrees or more instead of 90 degrees). This preliminary geometric configuration allows the fiber sheet laminate to be laminated without excess fibers, and the subsequent bending to the final angle proceeds without wrinkle formation, achieving both correct shape and surface quality
Solution Approach 2:
The invention changes the angle parameter of the forming die from being equal to the final bent angle to being larger than it (180 degrees or more for 90-degree bends). This parameter change reduces the peripheral length difference during bending, preventing wrinkle occurrence while maintaining the final cross-sectional shape
4Shape
If layers of fiber sheet laminate are caused to slide during bending to accommodate shape changes, then the fiber sheet can be formed to the final shape, but wrinkles occur when layers do not slide appropriately
Solution Approach 1:
The forming die is designed in advance with angles larger than the final bent angle, which reduces the amount of bending required. This preliminary configuration minimizes interlayer sliding demands, allowing layers to slide appropriately without causing wrinkles, thus achieving the final shape with high manufacturing precision
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
The purpose of the present invention is to suppress the generation of wrinkles during a bending process and to shorten the time period for lamination. A forming method according to the present disclosure comprises: a laminating step for forming an intermediate formed article (32) by supplying and laminating a fibrous sheet onto forming surfaces (22A, 22B) of a forming die (20) for forming the intermediate formed article (32); and a bending process step for performing a bending process on the intermediate formed article (32), which is laminated on the forming surfaces (22A, 22B) and has a shape that corresponds to the forming die (20), to yield a formed article. The forming surfaces (22A, 22B) have shapes that correspond to the intermediate formed article (32) to be formed. The second forming surface (22B) is bent with respect to the first forming surface (22A) among the forming surfaces (22A, 22B), and the angle formed by the first forming surface (22A) and the second forming surface (22B) is greater than the bending angle of the cross-section of the formed article to be formed and less than 180 degrees.