FRP Stringer Positioning Jig Thermal Stability
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Solution Overview
Problem
Conventional positioning jigs for manufacturing fiber-reinforced plastic structures are expensive, prone to thermal expansion issues, and can damage bag films, leading to positional inaccuracies and reduced quality of the molded components.
Innovation Solution
A device with a positioning part integrated into the mold or plate-like member, using a plate material with a linear expansion coefficient matching the FRP, engages with the long member to maintain positional accuracy and reduce costs by eliminating the need for complex jigs and minimizing Invar usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional positioning jig is used to position mandrels on the skin, then the mandrels can be positioned at predetermined locations, but the positioning jig becomes extremely expensive due to complex manufacturing processes requiring five-axis machining and cutting metal blocks into precise shapes
Solution Approach 1:
The patent uses a simplified positioning jig that copies only the essential positioning function rather than replicating the complex geometry of the skin surface. The jig comprises a frame with blocks that engage mandrels through simple mechanical engagement features, eliminating the need for expensive five-axis machining while maintaining positioning accuracy.
Solution Approach 2:
The positioning jig is divided into separate functional components: a frame structure for support, blocks for mandrel engagement, and springs for applying contact force. This segmentation allows each component to be manufactured independently using simpler processes, reducing overall manufacturing complexity and cost.
2Ease of manufacture
If a positioning jig with multiple blocks and springs is used to position mandrels, then positioning can be achieved without complex cutting work, but the jig becomes expensive due to the large number of components required
Solution Approach 1:
The patent merges the positioning and support functions into an integrated frame structure with blocks that are directly mounted on the frame. This consolidation reduces the number of separate components compared to designs with multiple independent blocks and springs, simplifying assembly while maintaining positioning capability.
3Manufacturing precision
If the positioning jig is made from Invar material to prevent thermal expansion, then positional accuracy is maintained during heating, but the cost increases significantly due to the massive amount of Invar material required
Solution Approach 1:
The patent applies Invar material only to the specific portions of the positioning jig that require thermal stability - namely the blocks and frame elements that directly contact and position the mandrels. This localized application of Invar maintains positional accuracy during heating while minimizing material costs compared to constructing the entire jig from Invar.
4Manufacturing precision
If a positioning jig presses mandrels from the upper side through a bag film, then positioning can be achieved, but the bag film becomes damaged due to rubbing and friction
Solution Approach 1:
The patent inverts the conventional approach by positioning the mandrels from the lower side through the bag film rather than from the upper side. The positioning jig contacts the mandrels through the bottom surface, eliminating the rubbing and friction that would otherwise damage the bag film while maintaining effective positioning capability.
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 solution ensures high positional accuracy and quality of the molded long member while reducing production costs and avoiding bag film damage, using a simpler, cost-effective setup that maintains positional integrity during thermal expansion.
Implementation Method 1
the positioning part is provided with a plate material having a linear expansion coefficient approximate to that of the FRP
Data Source
AI summary
A device 100 for molding a fiber-reinforced plastic structure is a device for manufacturing a fiber-reinforced plastic structure 200 integrating a stringer 2, which is a fiber-reinforced plastic member having a longer dimension in a longitudinal direction D than in a direction perpendicular to the longitudinal direction D, with a skin 1, which is a fiber-reinforced plastic member. The skin 1 is provided with a positioning plate 3, which is disposed along the skin 1 and engages with a bottom surface 201 of an end part 21 of a mandrel 20 for molding the stringer 2. The positioning plate 3 positions the stringer 2 relative to the skin 1, at least in the direction intersecting the longitudinal direction D.