Incised Prepreg Molding for Complex Shapes
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Solution Overview
Problem
Current methods for producing fiber-reinforced plastics with complex shapes face challenges in achieving high mechanical properties and productivity, as continuous fibers have poor shape conformability and discontinuous fibers result in uneven fiber distribution and mechanical property variations.
Innovation Solution
A method involving the use of incised prepregs with unidirectionally oriented reinforcing fibers, where sheet substrates are placed in a mold to form overlapping and non-overlapping portions, and then heated and pressed to produce fiber-reinforced plastics with complex shapes, ensuring high mechanical properties and improved productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If continuous fibers are used as reinforcing fibers in intermediate substrates, then high mechanical properties are obtained, but shape conformability to mold is poor and it is difficult to conform joining portions to desired shapes
Solution Approach 1:
The continuous fiber prepreg is divided into multiple incised prepreg sheets with incisions made at specific intervals. This segmentation allows the fiber bundles to be separated into manageable sections that can conform to complex mold shapes while maintaining the continuous fiber structure within each section, thus preserving mechanical properties while improving shape conformability.
Solution Approach 2:
The incisions create a multi-layered structure where fiber bundles are separated in the thickness direction. This dimensional change allows the incised prepreg sheets to bend and conform to three-dimensional mold surfaces more effectively while the continuous fibers within each bundle maintain their load-bearing capacity.
2Shape
If discontinuous reinforcing fibers randomly oriented are used as reinforcing fibers in intermediate substrate, then shape conformability is improved, but fiber content is low and mechanical properties are poor
Solution Approach 1:
Instead of using completely random discontinuous fibers, the invention segments continuous fibers into bundles through incisions. This creates a controlled discontinuous structure where fiber bundles maintain their orientation and density while being able to conform to mold shapes, thus improving both shape conformability and mechanical properties compared to random discontinuous fibers.
Solution Approach 2:
The incisions create local variations in fiber distribution where fiber bundles are concentrated in specific regions between incisions. This local quality ensures that each region maintains sufficient fiber content and mechanical properties while the overall structure can conform to complex shapes through the arrangement of multiple incised sheets.
3Shape
If incised prepreg sheets are cut into shape conformity with mold, then complex shapes can be produced, but it takes time and effort and yield is low resulting in poor productivity
Solution Approach 1:
The incisions are made in advance during prepreg production, creating pre-divided fiber bundles that are ready for molding. This preliminary action eliminates the need for time-consuming on-site cutting and shaping operations, as the incised prepreg sheets can be directly placed and molded into complex shapes, significantly improving productivity.
Solution Approach 2:
The invention changes the physical structure of the prepreg by introducing incisions with specific parameters (interval, depth, width) that can be optimized for different mold shapes. This parameter change allows the same incised prepreg product to be used for various complex shapes without requiring custom cutting for each application, thereby improving productivity.
4Productivity
If discontinuous fibers are used in intermediate substrate, then fiber distribution unevenness or orientation unevenness occurs, but mechanical properties deteriorate or great variation in values occurs resulting in decreased rigidity or strength in joining portions
Solution Approach 1:
The incisions create uniform segments of fiber bundles at regular intervals, ensuring consistent fiber distribution and orientation throughout the incised prepreg sheets. This segmentation prevents the unevenness that occurs with random discontinuous fibers while maintaining production efficiency, as the segmented structure can be easily manufactured and consistently reproduced.
Solution Approach 2:
The incisions create a homogeneous structure where fiber bundles are uniformly distributed at regular intervals throughout the prepreg sheet. This homogeneity ensures consistent mechanical properties across different regions and between different batches, eliminating the great variation that occurs with random discontinuous fiber arrangements while maintaining production efficiency.
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 allows for the productive production of fiber-reinforced plastics with complex shapes and high mechanical properties by optimizing fiber orientation and distribution, enhancing both the strength and rigidity of the joining portions while maintaining high yield and efficiency.
Implementation Method 1
a molding step of heating and pressing the plurality of sheet substrates A
Data Source
AI summary
Provided is a method for producing a fiber-reinforced plastic having high mechanical properties and high productivity during molding of a complicated shape. A method for producing a fiber-reinforced plastic using a sheet substrate A is provided, the sheet substrate A being a substrate including one or more sheets of incised prepreg a, the incised prepreg a being a prepreg including unidirectionally oriented reinforcing fibers and a resin and having a plurality of incisions dividing the reinforcing fibers formed in the prepreg, wherein the method for producing a fiber-reinforced plastic includes a placement step (A) of placing a plurality of sheet substrates A in a mold such that each of the sheet substrates A forms an overlapping portion in which the sheet substrate A overlaps one or more other sheet substrates A and a non-overlapping portion in which the sheet substrate A does not overlap any other sheet substrates A, and a molding step of heating and pressing the plurality of sheet substrates A, and the total area of the overlapping portion and the non-overlapping portion is 50 to 100% relative to the area of a mold surface.