Composite Mold Thermal Expansion Thickness Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for manufacturing composite materials with concave shapes, such as U-shaped beams, fail to control thicknesses and achieve satisfactory surface conditions, leading to increased manufacturing costs and fiber breakage during geometric corrections.
Innovation Solution
A process using a mold and counter-mold system made of metal, where the mold is in two parts with controlled spacing, allowing for expansion during polymerization, and a gas-permeable membrane to ensure homogeneous impregnation and surface smoothing, while the counter-mold has openings for gas passage and is designed to accommodate the inside surface geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a U-shaped substrate is used to form the inside surface of a U-shaped beam, then the preform can be automatically draped and the inside surface geometry is defined, but the thickness control and surface quality at the outside surface cannot be satisfied
Solution Approach 1:
The mold is divided into two separate parts: a first mold for the inside surface and a second mold for the outside surface. This segmentation allows each mold to be optimized independently for its specific function, enabling precise control of thickness and surface quality at the outside surface while maintaining the automatic draping capability through the U-shaped substrate configuration.
Solution Approach 2:
A gas-permeable membrane is introduced as an intermediary element between the preform and the mold surfaces. This membrane ensures homogeneous impregnation of the preform by allowing gas passage while maintaining the structural integrity and surface quality of the composite material, thereby improving manufacturing precision without compromising the ease of manufacture.
2Ease of manufacture
If geometric correction is performed after polymerization to achieve desired shape, then the piece can be assembled with adjacent pieces, but manufacturing cost increases and fiber breakage occurs
Solution Approach 1:
The mold is designed with built-in compensation for thermal contraction during cooling. The mold dimensions are pre-adjusted to account for the expected shrinkage of the composite material during polymerization and cooling, so that the final piece emerges with the correct geometry without requiring post-polymerization correction operations. This eliminates fiber breakage and reduces manufacturing costs while maintaining assembly capability.
Solution Approach 2:
The mold is made of metal, which expands thermally during the polymerization process. This thermal expansion compensates for the contraction of the composite material, ensuring that the mold maintains proper contact and dimensional control throughout the cooling phase. The result is accurate geometry without the need for expensive and fiber-damaging geometric correction operations.
3Device complexity
If a non-expandable counter-mold is used, then the device cost is reduced, but the piece cannot be demolded due to tightening during cooling
Solution Approach 1:
The mold is made of metal, which expands thermally during the polymerization process. This thermal expansion compensates for the contraction of the composite material, ensuring that the mold maintains proper contact and dimensional control throughout the cooling phase. The result is accurate geometry without the need for expensive and fiber-damaging geometric correction operations.
Solution Approach 2:
The mold material properties are changed from non-expandable to expandable (metal) to enable thermal compensation. This parameter change allows the mold to adapt to the thermal contraction of the composite material during cooling, facilitating easy demolding while maintaining manufacturing precision. The metal mold's thermal expansion property resolves the contradiction between device simplicity and demolding capability.
4Reliability
If a microporous fabric membrane is used, then gas passage is enabled and matrix product is blocked, but the surface smoothing function is compromised
Solution Approach 1:
A gas-permeable membrane is introduced as an intermediary element between the preform and the mold surfaces. This membrane ensures homogeneous impregnation of the preform by allowing gas passage while maintaining the structural integrity and surface quality of the composite material, thereby improving manufacturing precision without compromising the ease of manufacture.
Solution Approach 2:
The gas-permeable membrane functions as a flexible thin film that selectively allows gas passage while blocking the matrix product. This thin film structure maintains surface quality by providing a smooth interface between the preform and the mold, while still enabling the necessary gas exchange for homogeneous impregnation. The membrane's flexibility allows it to conform to the mold surface, ensuring proper surface smoothing.
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 precise control of thicknesses and surface quality, reducing manufacturing costs and fiber breakage by enabling demolding without contraction issues, resulting in cost-effective production of composite materials with complex shapes.
Implementation Method 1
The intake of gases into the first chamber 12 brings about the diffusion of the product that is able to form the matrix in the entire preform
Implementation Method 2
the semi-sealed membrane 16 consists of a microporous fabric, whereby the small diameter of the pores makes possible the passage of gases but blocks the passage of viscous fluids such as the product that is able to form the matrix
Implementation Method 3
using a mold that is made in at least two parts and means for controlling the spacing of said at least two parts that are contiguous using the expansion phenomenon during the polymerization phase
Implementation Method 4
a gas-permeable membrane to ensure homogeneous impregnation and surface smoothing
Data Source
AI summary
A process for manufacturing a piece made of composite material with a hollow form and including a fiber preform (50) that is embedded in a matrix, includes placing the preform (50) in a first chamber (64) delimited by a mold (52) that is in contact with the surface of the piece to be produced outside of the hollow form and a counter-mold (54) that is in contact with the surface of the piece to be produced inside of the hollow form, and using a mold (52) that is made in at least two parts (52.1, 52.2) and elements (78) for controlling the spacing of the at least two parts (52.1, 52.2) that are contiguous using the expansion phenomenon during the polymerization phase.