Continuous Molding of Thermoplastic Laminates for Closed Cross Sections
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Solution Overview
Problem
Existing methods for fabricating thermoplastic composite parts, such as pultrusion and autoclave consolidation, face limitations in producing parts with closed cross-sectional shapes and are costly at higher production rates, while also compromising the structural properties of pre-consolidated laminates.
Innovation Solution
A continuous post-forming process that involves heating a pre-consolidated thermoplastic laminate to a temperature below its melting point and incrementally forming features using tool dies, allowing for the production of parts with closed cross sections and curvatures without compromising the laminate's structural properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pultrusion process is used to produce continuous composite parts, then productivity is improved, but the ability to produce parts with closed cross-sectional shapes is limited
Solution Approach 1:
The patent applies parameter changes by heating the pre-consolidated laminate to a temperature above its glass transition temperature but below its melting point, transforming the material from a rigid state to a formable state. This temperature parameter change enables the laminate to be shaped into closed cross-sectional profiles while maintaining continuous production, thereby resolving the contradiction between productivity and adaptability.
2Manufacturing precision
If autoclave consolidation process is used to produce composite parts, then manufacturing precision is improved, but productivity decreases and cost increases at higher production rates
Solution Approach 1:
The patent applies preliminary action by pre-consolidating the laminate before the continuous shaping process. The laminate is pre-consolidated to a sufficient degree in advance, then heated and formed continuously through the shaping zone. This preliminary consolidation maintains manufacturing precision while enabling high-speed continuous production, resolving the contradiction between precision and productivity.
3Ease of manufacture
If heating temperature is increased to allow forming of the laminate, then ease of manufacture is improved, but structural properties of the laminate may be compromised
Solution Approach 1:
The patent applies parameter changes by precisely controlling the heating temperature within a specific range: above the glass transition temperature to enable forming, but below the melting point to preserve structural properties. This controlled parameter change allows the laminate to become formable while maintaining its strength and structural integrity throughout the continuous shaping process.
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
Enables the efficient, low-cost, high-rate production of composite parts with favorable structural properties in continuous lengths, including closed cross-sectional shapes, by maintaining the laminate's performance and structural integrity throughout the molding process.
Implementation Method 1
The pre-consolidated laminate is heated to a temperature sufficient to allow forming of the laminate but below the melting point of the laminate
Implementation Method 2
The heated laminate is fed substantially continuously through a forming zone where one or more features are incrementally formed into the heated laminate
Data Source
AI summary
An elongate thermoplastic composite member is fabricated by a continuous molding process. A pre-consolidated thermoplastic laminate is softened by heating it to a temperature below its melting layup, and is fed substantially continuously through multiple sets of tool dies. The tool dies incrementally mold portions of softened laminate over a mandrel to form the laminate into a shape having a closed cross section.