Fiber-Reinforced Plastic Molding Using Loss Angle Monitoring
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Solution Overview
Problem
Existing methods for producing molded fiber-reinforced plastic articles with inorganic reinforcing fibers and thermosetting resins face challenges in accurately controlling the fiber volume content, leading to inconsistent mechanical properties due to difficulties in determining the right time for press molding based on varying hardening reaction rates of resins, resulting in leakage, voids, or insufficient impregnation.
Innovation Solution
A method involving dynamic viscoelasticity measurements to determine the pressurization start range by measuring the loss angle of the thermosetting resin, allowing for precise control of pressure application within a specific elapsed time range (0.55 to 1.57 rad) to ensure accurate fiber volume content, preventing resin leakage and void formation while ensuring sufficient impregnation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pressure application is started immediately after heating the fiber-resin mixture to molding temperature, then production efficiency is improved, but resin leakage occurs and fiber volume content cannot be controlled accurately
Solution Approach 1:
The patent applies preliminary action by measuring the loss angle δ at molding temperature before pressure application to determine the appropriate timing. This preliminary measurement allows the system to identify when the resin has reached the optimal viscosity state for pressure application, preventing resin leakage while ensuring efficient production. The loss angle measurement is performed in advance to guide the pressure application timing.
2Manufacturing precision
If pressure application is delayed to prevent resin leakage, then fiber volume content control is improved, but production efficiency decreases
Solution Approach 1:
The patent implements feedback by continuously monitoring the loss angle δ of the thermosetting resin during heating and using this information to determine the optimal timing for pressure application. The feedback mechanism provides real-time information about resin viscosity changes, allowing the system to apply pressure at the precise moment when fiber volume content can be controlled accurately without unnecessarily delaying production.
3Productivity
If the hardening reaction rate of the thermosetting resin is increased, then production efficiency is improved, but it becomes difficult to control the timing for pressure application
Solution Approach 1:
The patent replaces traditional mechanical or time-based timing methods with a rheological measurement system that monitors the loss angle δ. This substitution allows for precise detection of resin viscosity changes during the hardening reaction, providing an objective criterion for determining pressure application timing regardless of the hardening reaction rate. The measurement system automatically identifies the optimal timing point based on resin properties rather than fixed time intervals.
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 accurate control of fiber volume content within ±5% of the predetermined value, enhancing the mechanical properties and production efficiency of molded fiber-reinforced plastic articles, suitable for applications like aircraft components.
Implementation Method 1
a temperature of the thermosetting resin or the fiber-resin mixture reached a molding temperature (at which a hardening reaction proceeds)
Implementation Method 2
measuring the loss angle δ of the thermosetting resin or the fiber-resin mixture in a dynamic viscoelasticity measurement
Data Source
AI summary
A method for producing a molded article of a fiber-reinforced plastic include molding a fiber-resin mixture containing an inorganic reinforcing fiber and a thermosetting resin under heat and pressure. The elapsed time since the thermosetting resin reached a molding temperature at which a hardening reaction proceeds is measured, the loss angle δ of the thermosetting resin is measured in a dynamic viscoelasticity measurement, and the relationship between the elapsed time and the loss angle δ is evaluated to calculate the range of the elapsed time, within which the loss angle δ is 0.55 to 1.57 rad after the loss angle δ reached the maximum value, as the pressurization start range. The fiber-resin mixture is heated to the molding temperature and pressure application to the fiber-resin mixture is started within the pressurization start range, to obtain the molded article of the fiber-reinforced plastic.