Composite Stringer Forming via Progressive Die Conveyor
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Solution Overview
Problem
Current methods for forming composite aircraft stringers are inefficient, requiring pre-forming with vertical punch operations, unique forming tools for each part, and multiple passes to build up a laminate, limiting production speed and increasing cycle time.
Innovation Solution
A system and method using an expandable pallet and a die conveyor with multiple die sections that progressively shape a laminated charge into a composite structure as the pallet moves linearly, allowing for continuous fabrication along a manufacturing line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pre-forming with vertical punch style forming operations is used, then the composite structure can be formed, but the cycle time increases and production speed is limited
Solution Approach 1:
The forming process is divided into multiple die sections arranged in series along the conveyor path. Each die section performs a specific forming action on different portions of the composite structure, allowing continuous progression through the forming process without requiring complete repositioning or reclosing of a single large punch tool.
Solution Approach 2:
The patent implements a continuous forming process where the expandable pallet moves through multiple die sections in sequence, and the die sections progressively close on the laminated charge as it moves along the conveyor. This eliminates the start-stop nature of traditional vertical punch operations and maintains continuous productive action throughout the forming cycle.
2Manufacturing precision
If a unique forming tool is used for each part, then the part can be formed with precision, but tooling changes are required and manufacturing efficiency decreases
Solution Approach 1:
The patent designs a universal forming system with a standardized expandable pallet and series of die sections that can form multiple different composite structures by adjusting the die section configurations. This single multi-functional tooling system replaces the need for multiple unique forming tools, allowing continuous manufacturing without tooling changes while maintaining precision through controlled die section actions.
3Ease of manufacture
If multiple passes are used to build up laminate, then the full laminate can be constructed, but the cycle time increases
Solution Approach 1:
The patent applies the laminated charge to the expandable pallet in a preliminary step before the forming process begins. The charge is prepared and positioned in advance, allowing the subsequent forming operation to proceed continuously through the die sections without requiring interruptions for charge application or tooling repositioning. This preliminary preparation enables the full laminate to be constructed in a single continuous pass rather than requiring multiple separate passes.
Data Source
AI summary
An example method of forming a composite structure is described that includes applying a laminated charge onto an expandable pallet, moving the expandable pallet at a translation rate and relative to a die conveyor that comprises a plurality of die sections, and driving the plurality of die sections on the die conveyor at an angle relative to the expandable pallet so as to drive the plurality of die sections progressively deeper into a recess defined by the expandable pallet and shape the laminated charge into at least part of a shape of the composite structure.