Fiber-Reinforced Resin Heating via Conductive Fibers
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Solution Overview
Problem
Existing methods for producing fiber-reinforced resin molded bodies face issues with temperature unevenness between the inside and surface of the precursor, leading to prolonged heating times and undesirable softening states due to the use of rollers in transfer trays, which can degrade mechanical properties and appearance.
Innovation Solution
A method involving a heating process where a fiber-reinforced resin molded body precursor with conductive fibrous materials is heated using heating apparatuses and held by electrodes, allowing concurrent heating of the inside and surface through electrical resistance, reducing temperature unevenness and shortening heating time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a thermoplastic resin sheet is placed on a transfer tray with rollers and transferred to a heating furnace, then the production cycle time is reduced and mass production is enabled, but indentations from the rollers are left on the resin sheet degrading mechanical properties and appearance
Solution Approach 1:
The harmful rollers are completely removed from the transfer tray structure. The patent replaces the roller-based transfer mechanism with a roller-free transfer tray that uses a smooth surface design, eliminating the source of indentations while maintaining the ability to transfer the resin sheet efficiently through the heating furnace
Solution Approach 2:
The patent introduces a transfer tray with a specific intermediate structure that mediates between the need for efficient transfer and the need for surface quality. The transfer tray uses a smooth, roller-free surface that allows the resin sheet to be transferred without direct contact with protruding elements, thus preventing indentations while enabling continuous production
2Speed
If the surface of the fiber-reinforced resin molded body precursor is directly heated by heating apparatus, then rapid heating of the surface is achieved, but the inside is difficult to heat causing temperature unevenness
Solution Approach 1:
The patent applies different heating characteristics to different regions of the resin sheet. The transfer tray is designed with selective heating zones where the tray itself can be heated to transfer thermal energy to the resin sheet, creating a gradient that addresses both surface and internal heating needs simultaneously
Solution Approach 2:
The transfer tray acts as an intermediary heat transfer medium. Instead of direct heating of the resin sheet surface only, the heated transfer tray serves as a thermal mediator that conducts heat into the interior of the resin sheet, distributing temperature more uniformly throughout the material
3Temperature
If heating time is extended to heat the inside of the fiber-reinforced resin molded body precursor, then uniform temperature is achieved, but the surface becomes overheated and loses desired softened state
Solution Approach 1:
The patent implements localized heating characteristics where different regions of the resin sheet receive different amounts of heat. The transfer tray design enables zones of intense surface heating and zones of gradual internal heating, allowing the process to achieve uniform temperature distribution without prolonged exposure that would overheat the surface
Solution Approach 2:
The heating process is made continuous and efficient through the heated transfer tray mechanism. The tray maintains thermal energy throughout the transfer process, providing continuous gentle heating to the interior while the resin sheet moves through the system, eliminating the need for extended heating cycles that would cause surface degradation
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 temperature unevenness and heating time, ensuring a uniform softened state is achieved, maintaining the desired mechanical properties and appearance of the molded body.
Implementation Method 1
supplying current to the fiber-reinforced resin molded body precursor from the electrodes, thereby softening the fiber-reinforced resin molded body precursor
Implementation Method 2
actuating the heating apparatuses while supplying current to the fiber-reinforced resin molded body precursor from the electrodes
Data Source
AI summary
A method for producing a fiber-reinforced resin molded body, including heating a fiber-reinforced resin molded body precursor containing thermoplastic resin as matrix resin to soften it and molding it in a molding die, where temperature unevenness between the inside and surface of the fiber-reinforced resin molded body precursor can be reduced. The method includes a first step of storing a fiber-reinforced resin molded body precursor containing thermoplastic resin as the matrix resin and containing conductive fibrous materials therein into a heating furnace with heating apparatuses while holding the precursor using a pair of holding tools, which also function as electrodes, and then actuating the heating apparatuses while supplying current to the precursor from the electrodes, thereby softening the precursor; and a second step of transferring the softened precursor to a molding die using the holding tools, and molding a fiber-reinforced resin molded body in the molding die.