Composite Tooling Fabrication Using Vacuum Infusion and Ceramic Coating
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Solution Overview
Problem
Composite carbon fiber tooling for fabricating composite parts is hindered by high material and labor costs, long lay-up and cure cycles, poor surface durability, and structural weaknesses due to expensive prepregs and archaic attachment methods, making it less viable for production compared to metallic tooling despite its advantages.
Innovation Solution
The use of low-cost dry fabrics and neat bismaleimide (BMI) resin with vacuum-assisted resin infusion and oven curing, along with a ceramic-filled surface coating and 3D woven pi-shaped preforms for enhanced durability and structural integrity, eliminates the need for autoclave cycles and reduces labor costs, providing a cost-effective and durable composite tooling solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If expensive prepregs and autoclave compaction are used, then manufacturing precision is improved, but acquisition cost increases significantly
Solution Approach 1:
The patent uses disposable vacuum-bagged tooling instead of expensive, reusable prepreg autoclave tooling. The vacuum bag with release fabric provides sufficient dimensional accuracy for production parts while being much cheaper to manufacture and replace if damaged, directly addressing the cost-precision tradeoff
Solution Approach 2:
The patent changes the manufacturing process parameters from autoclave high-pressure curing to vacuum-bag low-pressure curing. This parameter change allows using cheaper materials and processes while maintaining acceptable dimensional accuracy through proper vacuum bag design and release fabric selection
2Weight of moving object
If traditional composite tooling methods are used, then tooling weight is reduced, but labor time and cycle time increase significantly
Solution Approach 1:
The patent segments the tooling fabrication process into separate, parallelizable steps: substrate preparation, vacuum bagging, resin infusion, and curing. This segmentation allows different operations to be performed simultaneously or by different teams, reducing overall labor time while maintaining the lightweight composite structure
Solution Approach 2:
The patent replaces mechanical autoclave compression with vacuum pressure for resin infusion and curing. This substitution eliminates the need for expensive autoclave equipment and reduces cycle time while producing equally effective composite tooling with low weight
3Ease of manufacture
If polymeric surfaces are used on composite tooling, then ease of manufacture is improved, but surface durability and vacuum integrity deteriorate
Solution Approach 1:
The patent uses a composite surface system combining polymeric release fabric with a rigid substrate. The release fabric provides easy manufacturing and part release, while the substrate structure maintains vacuum integrity and surface durability. This composite approach resolves the contradiction between ease of manufacture and reliability
Solution Approach 2:
The patent introduces a release fabric as an intermediary layer between the tooling substrate and the production part. This intermediary provides the necessary surface properties for easy part release while the underlying substrate maintains structural integrity and vacuum seal, separating the conflicting requirements
4Ease of manufacture
If epoxy resins are used in composite tooling, then ease of manufacture is improved, but duration of action decreases due to thermal cycling degradation
Solution Approach 1:
The patent changes the resin selection parameters to use high-temperature tolerant resins such as BMI (bismaleimide) or cyanate ester instead of standard epoxy. This parameter change allows the tooling to withstand repeated production cure cycles at elevated temperatures, extending tool life while maintaining fabrication simplicity through similar processing methods
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 significantly reduces production life cycle costs, enhances tool surface durability, and improves structural integrity, allowing BMI tooling to compete with metallic tooling in terms of cost and performance while maintaining the advantages of composite tooling.
Implementation Method 1
vacuum-assisted resin infusion
Implementation Method 2
greatly enhanced abrasion and damage resistance
Implementation Method 3
oven curing
Data Source
AI summary
Composite tooling is fabricated with low cost dry fabrics and a neat resin instead of expensive prepregs. Dry, three-dimensional woven joint preforms are placed on a dry tool substrate and dry, 3D preforms are also placed between pre-cured egg crate-like junctions. The entire tool substrate and substrate-to-support structure joints are then resin-infused simultaneously through the use of rota-molded tooling aids, providing an additional reduction in cost. Tight control of resin content and distribution with vacuum infusion is thereby provided. This process eliminates the primary cause of structural weakness and cooling distortion, which typically occur at the attachment interface when existing methods are used. The preforms provide significantly greater pull-off strengths at interfaces than do hand-laid tie plies. Issues with tool surface durability are addressed through the use of ceramic-filled face coat.