In-Tool Compaction Inserts for Composite Stiffener Preforms
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Solution Overview
Problem
The compaction of out-of-plane features in composite structures, such as aircraft stiffeners, is difficult to perform in situ, often requiring separate work cells, additional tooling, and high thermal expansion tools, which can damage the preform and are costly in terms of time and energy.
Innovation Solution
An in-tool system using inserts with complementary faces to the out-of-plane features and tool cavities, along with a preform holding fixture, allows for compaction within the mold tool, reducing the need for separate facilities and enabling easy removal of the preform without damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate work cells with associated equipment and tooling are used to perform compaction, then compaction capability is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the compaction function into the main tooling cavity by incorporating an insert with a compaction surface that interfaces with the out-of-plane feature. This integration eliminates the need for separate work cells and associated equipment, reducing overall device complexity while maintaining compaction capability. The insert is positioned within the tool cavity and works in conjunction with the preform to achieve the desired compaction.
2Ease of manufacture
If high Coefficient-of-Thermal-Expansion (CTE) tooling is used to impart compaction, then compaction is achieved through thermal expansion, but time and energy consumption increase due to heating and cooling requirements
Solution Approach 1:
The patent replaces the thermal expansion-based compaction mechanism with a direct mechanical compaction system. The insert includes a compaction surface that mechanically contacts the out-of-plane feature of the preform, allowing compaction to be achieved through applied force during the molding process rather than requiring thermal expansion. This eliminates the need for high-temperature heating and subsequent cooling cycles, significantly reducing process time and energy consumption.
3Ease of manufacture
If out-of-plane features are loaded into tooling cavity, then compaction is required to fit the feature, but the feature may physically impact the tool and damage the preform
Solution Approach 1:
The patent applies preliminary action by pre-positioning the insert with the compaction surface within the tool cavity before loading the preform. The insert is configured to engage with the out-of-plane feature as it is loaded into the cavity, providing immediate compaction support and preventing the feature from impacting the tool walls. This preliminary arrangement ensures safe loading while achieving the necessary compaction to fit the feature within the cavity.
Data Source
AI summary
An in-tool system for compacting an out-of-plane feature of a composite structure. The in-tool system comprises a cavity formed in a tool, a stiffener preform, and an insert. The cavity has an angled surface. The stiffener preform includes an out-of-plane feature, where the out-of-plane feature has a compaction surface. The insert comprises a first face complementary to the angled surface of the cavity and a second face complementary to the compaction surface of the out-of-plane feature. The first face is opposite the second face.