Composite T-Stiffener Net Edges Without Edging and Sealing
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Solution Overview
Problem
The existing manufacturing methods for stiffeners with a 'T' cross section require time-consuming edging and sealing processes due to poor edge quality, leading to delamination and corrosion issues, especially when integrated with metal parts.
Innovation Solution
A method involving laminate folding, semicircular edge molding, and application of semi-cured and fresh prepreg fiberglass strips to create a 'net' edge without edging, ensuring a smooth and durable finish.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If edging is performed after curing to achieve clean edges, then edge quality is improved, but production time and complexity increase
Solution Approach 1:
The invention applies a release agent to the mold cavity before curing, which prevents resin and fiber accumulation at the edges during the curing process itself. This preliminary action eliminates the need for subsequent edging operations, achieving clean edges without additional time-consuming steps after curing.
Solution Approach 2:
The invention skips the traditional edging step by using a release agent that prevents material accumulation during curing. This allows the process to rush through to completion without requiring the separate edging operation that would otherwise be necessary to achieve clean edges.
2Manufacturing precision
If edging is performed to remove excess material, then edge precision is improved, but device complexity and material consumption increase
Solution Approach 1:
The invention extracts the function of preventing material accumulation from the edging operation itself. By applying a release agent to the mold cavity, the prevention of excess material formation is integrated into the curing process, eliminating the need for separate edging equipment and operations.
Solution Approach 2:
The release agent acts as an intermediary substance between the mold cavity and the composite material during curing. This intermediary prevents resin and fiber accumulation at the edges, achieving precise edges without requiring complex edging equipment or post-curing material removal operations.
3Reliability
If sealing operations are performed near metal parts, then corrosion protection is improved, but manufacturing complexity increases
Solution Approach 1:
The release agent is applied to the mold cavity before curing, which preliminarily prevents resin and fiber accumulation at the edges. This preliminary action ensures that edges near metal parts are clean and properly formed from the start, eliminating the need for subsequent sealing operations to prevent corrosion.
Solution Approach 2:
The invention extracts the corrosion protection function from the sealing operation. By preventing material accumulation at the edges through the release agent during curing, the edges are inherently protected and properly formed, eliminating the need for separate sealing operations near metal parts.
Data Source
AI summary
Method to make a T shaped stiffener form from a stiffener preform (100) having a foot (130) configured to be in contact with an aircraft panel, and a sole (120) with an edge (120a). The manufacturing method includes: obtaining laminates (110a, 110b) formed of layers of composite material, folding the laminates (110a, 110b) to be L shaped in cross section, joining the laminates to form a T shaped preform (100), molding the edge of the sole (120a) so that the edge is semicircular in cross section, applying to the edge (120a) a strip of semi-cured carbon fabric (L1) and a fresh strip of prepreg fiberglass (L2), and curing the preform (100) to obtain the stiffener.