Staggered Bevel Tooling Dies for Composite Molding
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Solution Overview
Problem
In continuous compression molding processes for thermoplastic composite parts, stainless steel foils or kapton layers can get trapped, leading to wrinkles and reduced part quality, increasing scrap rates and production costs, especially when forming cross-section configurations with multiple bends and segments.
Innovation Solution
The implementation of tooling dies with a staggered bevel feature at the entry side, where the bevel length varies incrementally from the incoming edge, preventing excess material from being trapped and allowing smooth advancement of the pre-formed laminate, thereby preventing wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional tooling dies with uniform bevels are used, then the structure is simple and easy to manufacture, but stainless steel foils or kapton layers get trapped between the tooling dies causing wrinkles
Solution Approach 1:
The bevel feature is divided into multiple segments along the entry side of the tooling die, with each segment having a different length. This segmentation allows the bevel to progressively guide the pre-formed laminate and prevent trapping of foils or kapton layers, thereby eliminating wrinkles while maintaining structural feasibility
Solution Approach 2:
Different portions of the bevel feature are given different lengths to create localized variations in the tooling die structure. The first bevel segment has a different length than the second bevel segment, creating local quality differences that prevent material trapping at specific locations where wrinkles would form
2Productivity
If uniform bevel length is used across all segments, then the tooling die is easier to manufacture, but excess material gets trapped leading to increased scrap rates
Solution Approach 1:
The bevel feature introduces a dynamic gradient in the tooling die structure, where the progressive variation in bevel lengths creates a controlled material flow path. This dynamic structure adapts to the pre-formed laminate during compression molding, ensuring smooth material advancement and preventing trapping, thereby reducing scrap rates and improving production efficiency
3Manufacturing precision
If conventional uniform tooling dies are used, then device complexity is low, but wrinkles form in the foils and pre-formed laminate reducing part quality
Solution Approach 1:
The bevel feature employs asymmetric design where the first and second bevel segments have different lengths rather than being symmetric and uniform. This asymmetry creates a progressive guiding effect that prevents foil or kapton layer trapping and eliminates wrinkles, improving part quality while the asymmetric design remains manufacturable
Data Source
Figure 1
Figure 2A~2E
Figure 3A~3B
AI summary
Continuous compression molded process and apparatus for fabricating thermoplastic composite parts from pre-formed thermoplastic composite laminates (5) with tooling dies (2,6) have a staggered bevel feature (44) at an entry side of the tooling dies (2,6). Staggering the length of the bevel feature (44) in each section between bends in a surface contour along the width of the incoming edge of the tooling dies (2,6) prevents excess material from being trapped and forming wrinkles in the finished thermoplastic part. The length of the taper (14,48) in each section along the width of the tooling dies (2,6) is aligned with a pulsed advancement distance of the pre-formed part (5).