Wax Core Molding for Flat Hollow Composite Surfaces
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Solution Overview
Problem
Existing methods for manufacturing fiber-reinforced resin articles with hollow or U-shaped structures struggle to control the shape of the surface facing the core during molding, particularly when forming bent or curved wall surfaces.
Innovation Solution
A manufacturing method involving a core with incompatible wax materials, where a stamper part with a higher softening temperature forms a shape on the surface of the cured product by expanding against the prepreg preform in a press metal mold, followed by core removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a core comprising a single wax material is used to manufacture fiber-reinforced resin articles with hollow or U-shaped structures, then the core can be removed after curing, but the surface flatness and shape control of the cured product facing the core are poor
Solution Approach 1:
The core is divided into multiple sections along its longitudinal direction, with each section comprising a different wax material having distinct melting points. This segmentation allows different parts of the core to perform different functions: lower-melting-point materials provide expansion pressure for shaping, while higher-melting-point materials maintain structural integrity and surface contact for flatness control.
Solution Approach 2:
Different regions of the core are assigned different wax materials with specific properties tailored to local requirements. The lower-melting-point wax materials are positioned to provide expansion pressure where needed, while higher-melting-point materials are positioned at surface-contact regions to maintain geometric fidelity and prevent deformation during curing.
2Shape
If the core expands during heating to form hollow or U-shaped structures, then the desired structural shape is achieved, but the surface shape control becomes difficult
Solution Approach 1:
The core is segmented into multiple sections with different wax materials along its length, allowing controlled differential expansion. This enables the core to expand sufficiently to form hollow or U-shaped structures while maintaining surface contact in critical regions to preserve surface flatness and geometric accuracy.
Solution Approach 2:
The core utilizes wax materials with different melting points and expansion characteristics. By selecting materials with appropriate thermal parameters, the core expands controllably during heating to achieve the desired hollow or U-shaped structure while maintaining surface integrity through regions with higher melting points that resist deformation.
3Ease of manufacture
If a single wax material is used in the core, then the core structure is simple, but incompatible materials cannot be separated after curing
Solution Approach 1:
Different wax materials are positioned at specific locations within the core based on their functional requirements. Lower-melting-point materials are positioned to provide expansion pressure, while higher-melting-point materials are positioned to maintain surface contact and structural integrity, with each material's location optimized for its specific function.
Solution Approach 2:
The core is designed so that lower-melting-point wax materials can be selectively removed first through melting and drainage, followed by removal of higher-melting-point materials. This staged removal process allows for efficient core extraction while enabling recovery and reuse of the higher-melting-point materials that maintained surface fidelity during curing.
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 method enables the formation of fiber-reinforced resin articles with improved surface flatness and uniform wall thickness, reducing mechanical characteristic variations and enhancing strength.
Implementation Method 1
a core having an expansion part including a first wax material and a stamper part including a second wax material... the first wax material has a softening temperature lower than that of the second wax material... the first wax material partially or completely melts
Implementation Method 2
the second wax material has a softening temperature higher than that of the first wax material... the stamper part is disposed on a surface of the core... a portion mirroring a shape of a surface of the stamper part is formed on a surface of the cured product
Implementation Method 3
the material of the first fusible part and the material of the second fusible part are mutually incompatible... in the molding step, the first fusible part partially or completely melts, and the second fusible part does not partially or completely melt
Data Source
Figure 1~2(b)
Figure 3(a)~3(b)
Figure 4~5
AI summary
The present invention provides an improvement relating to a method for producing a fiber-reinforced resin article at least partially having a structure comprising a bent or curved wall surface, such as a hollow structure part or a U-shaped cross-sectional structure part. A method for manufacturing a fiber-reinforced resin article according to the present invention has a molding step of heating, in a press metal mold, a prepreg preform together with a core comprising a wax material to obtain a cured product and a core removal step of removing the core from the cured product, where the core has an expansion part comprising a first wax material and a stamper part comprising a second wax material that is incompatible with the first wax material, the stamper part is disposed on a surface of the core, and a portion mirroring a shape of a surface of the stamper part is formed on a surface of the cured product.