Thermal-Fusion Layer for Epoxy-Carbon Composite Surface Quality
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Solution Overview
Problem
Conventional epoxy resin-carbon fiber composite materials often develop surface defects during molding and curing, such as voids, uneven surfaces, and residual release agents, which require costly defect removal processes and compromise the product's appearance and functionality.
Innovation Solution
A method involving a thermal-fusion material, which is initially in a solid state at room temperature, transitions to a gel state at a first temperature and solidifies at a second temperature, fully fusing with the prepreg layup to form a resin-based composite structure without the need for extra defect removal processes, using a resin-based polymer compound like CoPA, CoPES, or Phenoxy, and controlling its thickness for enhanced hardness and air permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional molding and curing process is used for epoxy resin-carbon fiber composite materials, then the composite structure can be formed, but surface defects such as voids, uneven surfaces, and residual release agents are generated
Solution Approach 1:
A release agent removal layer is applied to the mold surface before molding to prevent release agent residue from contaminating the composite surface during curing, eliminating the need for subsequent defect removal processes
Solution Approach 2:
The release agent removal layer is designed with porous structure to allow air and release agents to pass through during molding, preventing voids and surface defects while maintaining effective release properties
2Manufacturing precision
If defect removing processes such as sandblasting, potting, and sanding are performed, then surface defects can be removed, but the process becomes complicated and costly
Solution Approach 1:
The harmful release agent residues are extracted from the mold surface by the release agent removal layer before molding occurs, preventing surface contamination and eliminating the need for subsequent defect removal processes
Solution Approach 2:
The release agent removal layer is applied in advance to the mold surface to prevent surface defects before they occur, eliminating the need for post-molding defect removal processes
3Object-generated harmful factors
If air-venting layer made of carbon or glass fiber veil is used, then air can be vented during molding, but appearance defects are formed and are difficult to improve due to high-porosity property
Solution Approach 1:
The release agent removal layer utilizes porous structure to enable air and release agent passage during molding, preventing voids and surface defects while maintaining a smooth appearance without the high-porosity problems of fiber veils
Solution Approach 2:
The release agent removal layer acts as an intermediary between the mold surface and the composite material, allowing air and release agents to pass through while preventing direct contact between mold imperfections and the final surface
4Manufacturing precision
If RTM process is used to ensure smooth surface, then surface quality is improved, but excessive content of epoxy resins (40%-60%) are required which reduces stiffness
Solution Approach 1:
The release agent removal layer extracts and removes air and release agent residues from the molding process, eliminating surface defects without requiring excessive epoxy resin content, thus maintaining low weight and high stiffness
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 produces a defect-free, resin-rich composite structure with improved surface quality and reduced need for release agents, achieving a smooth, high-quality finish without additional processing steps, suitable for applications like bicycle frames with enhanced stiffness-to-weight ratio and durability.
Implementation Method 1
the thermal-fusion material is in a solid state at a room temperature, transferred from the solid state to a gel state after the first temperature
Implementation Method 2
transferred from the gel state to the solid state after the second temperature
Implementation Method 3
A viscosity of the thermal-fusion material is decreased while raised from the first temperature to the second temperature
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A method for forming a resin-based composite structure is provided. The method includes: providing a prepreg layup, wherein the prepreg layup includes an epoxy resin-carbon fiber composite material; covering a thermal-fusion material on a surface of the prepreg layup; and performing a molding and curing process to fuse the thermal-fusion material with the prepreg layup. Wherein the molding and curing process includes: heating at a first temperature to melt, soften and fully fuse the thermal-fusion material with the prepreg layup; and heating at a second temperature to solidify the thermal-fusion material for forming the resin-based composite structure. Wherein the first temperature is lower than the second temperature.