Incised Prepreg Hot Forming for Wrinkle-Free Composite Shapes
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Solution Overview
Problem
Existing methods for forming fiber reinforced plastics by hot forming result in wrinkles and resin-enriched portions, leading to decreased surface quality and mechanical properties, especially when forming complex shapes.
Innovation Solution
A production method involving incised prepregs with specific incision patterns and distributions, combined with out-of-plane deformation and shear stress application, to form wrinkle-free preforms with improved shape conformity and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hot forming is used to form prepreg laminate into three dimensional shape, then productivity is improved and cheap wide width prepregs can be used, but wrinkles occur and resin-enriched portions are formed between reinforcing fibers and mold
Solution Approach 1:
The prepreg is divided into multiple strips by making incisions along the fiber direction, transforming a single continuous structure into segmented parallel strips. This segmentation allows each strip to independently conform to the mold surface during hot forming, preventing wrinkles and resin enrichment while maintaining high productivity with wide width prepregs.
2Adaptability or versatility
If slit tape prepregs are formed by cutting wide width prepreg, then narrow width prepregs can be obtained for complex shapes, but additional cutting step is required and material cost increases
Solution Approach 1:
The incisions are made in advance during prepreg manufacturing, creating pre-divided strips before lamination. This preliminary action eliminates the need for additional cutting steps after lamination, reducing process complexity while enabling complex three-dimensional shaping capability.
3Manufacturing precision
If incisions are made in prepreg, then wrinkle-free forming is achieved, but incision pattern must be precisely controlled
Solution Approach 1:
The incision pattern is defined by specific parameters: incisions made at regular intervals (50-200 mm) along the fiber direction, creating strips 5-50 mm wide. These controlled parameter changes ensure optimal balance between wrinkle prevention and structural integrity, achieving shape conformity without excessive complexity.
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 method enables the production of fiber reinforced plastics with enhanced surface quality and mechanical properties, suitable for complex shapes, by minimizing wrinkles and resin-enriched areas through controlled incision patterns and deformation techniques.
Implementation Method 1
the prepreg laminate cannot conform to the three dimensional shape completely, or a problem of a reinforcing fiber-free, resin-enriched portion between the reinforcing fibers and the mold because the reinforcing fibers brace
Implementation Method 2
at least a partial region of the preform having an approximate shape of the mold be pressed against the mold for planarization while a shear stress is applied
Data Source
Figure 1(a)~1(c)
Figure 2(a)~2(b)
Figure 3(a)~3(c)
AI summary
Provided is a production method for a fiber reinforced plastic, comprising: a laminating step of laminating a plurality of groups of prepregs containing an incised prepreg to obtain a prepreg laminate, when the incised prepreg is formed by providing at least a partial region in a prepreg containing unidirectionally oriented reinforcing fibers and a resin with a plurality of incisions that divide the reinforcing fibers, a forming step of disposing the prepreg laminate on the top surface of a mold containing the top surface and a side surface or disposing the prepreg laminate on the bottom surface of a mold containing the bottom surface and a side surface, and bending and forming the prepreg laminate along the side surface to obtain a preform having an approximate shape of the mold, and a solidifying step of disposing and solidifying the preform in a mold different than the mold used in the forming step. A production method by hot forming for a fiber reinforced plastic which exhibits excellent surface quality and mechanical properties is provided.