Nested Mold System for Undercut Composite Parts
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Solution Overview
Problem
Current mold systems for producing fiber composite plastic parts with complex shapes, especially those with undercut contours, face challenges in efficient production and material usage, as they often require axial removal and result in material loss and complex sealing processes.
Innovation Solution
A mold system comprising a multipart shaping mold and an enveloping mold, where the shaping mold is designed to be inserted into the enveloping mold, allowing for the creation of a pressure-tight chamber with minimal spacing and spacers for easy cleaning and reduced material loss, enabling the production of complex parts with undercut contours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the shaping mold is completely inserted into the enveloping mold, then the production of complex parts with undercut contours is enabled, but the intermediate spaces must be filled with duroplastic matrix material resulting in material loss
Solution Approach 1:
The shaping mold is inserted into the enveloping mold, creating a nested configuration where the inner mold (shaping mold) is placed within the outer mold (enveloping mold). This nesting enables the production of complex geometries with undercut contours while minimizing the intermediate space that would otherwise require filling with matrix material, thus reducing material loss.
2Ease of operation
If the cavity of the enveloping mold is considerably larger than the outer shape of the shaping mold, then the insertion is facilitated, but all intermediate spaces are filled with duroplastic matrix material meaning a loss of material
Solution Approach 1:
The enveloping mold cavity is designed with a specific geometric configuration that closely matches the outer shape of the shaping mold. This local optimization of the cavity geometry minimizes the intermediate spaces between the molds while still facilitating insertion, thereby reducing the amount of duroplastic matrix material that would otherwise fill these spaces and cause material loss.
3Reliability
If a trough-like frame structure with a cover is used, then the raw material can be sealed, but undercut contours cannot be produced since removal must always take place axially to the sealing surface
Solution Approach 1:
The mold system is divided into two separate functional components: the shaping mold (which defines the component geometry including undercut contours) and the enveloping mold (which provides sealing and consolidation). This segmentation allows the shaping mold to be designed specifically for producing complex geometries while the enveloping mold handles the sealing function, thereby enabling the production of undercut contours without compromising sealing reliability.
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 system allows for the cost-effective and efficient production of complex fiber composite parts with undercut contours by minimizing material loss and simplifying the cleaning process, while maintaining high quality and reducing the necessary closing force.
Implementation Method 1
oblique surfaces, by means of which the closing force of the enveloping mold is converted into a closing force for the shaping mold
Implementation Method 2
the duroplastic matrix material is inserted with very high injection pressure into a closed mold form, in which a fiber preform is located. The high injection pressure leads to a time reduction of the consolidation phase, while ensuring the full impregnation of the fiber reinforcement structure.
Implementation Method 3
the mold form is closed and the fiber preform is compressed and consolidated at the same time because of the high mold internal pressure resulting from the closing forces of the hydraulic press
Data Source
AI summary
A mold system for a resin transfer molding process is presented, in which a cavity of a workpiece (1) to be produced is fully enclosed circumferentially by a multi-part shaping mold (2). The shaping mold (2) is enclosed in a sealed manner by an outer, two or more part enveloping mold (7, 8). A method for consolidating a fiber composite component with this mold system and a method for producing a fiber composite component on the basis of the RTM process is provided, in which the intermediate space between a shaping mold (2) and a surrounding enveloping mold (7, 8) is filled with resin during the resin injection. After curing the resin initially remains on the shaping mold (2) as a resin body but is destroyed during the demolding of the workpiece (1), at predetermined breaking points. The demolding of the workpiece (1) from the shaping mold (2) is assisted.