Hollow Component Outer Contour Precision via Inner Mandrel Inversion
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Solution Overview
Problem
Existing methods for producing fuselage segments struggle to maintain reliable tolerances on the outer face, leading to difficulties in forming a smooth outer skin, which is critical for aerodynamics.
Innovation Solution
A method involving the use of an inner contour closed along its circumference, where fibre material is laid and cured to form a component, allowing for precise outer contour formation and easy compensation of inner contour variations, enabling flush joining of components and maintaining aerodynamic integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a circular cylindrical shaped article is bandaged with prepreg material and cured, then fuselage segments can be produced, but it is difficult to reliably maintain tolerances on the outer face
Solution Approach 1:
The patent inverts the traditional approach by using an inner contour (mandrel) to define the outer surface geometry. Instead of trying to control the outer face directly through bandaging, the inner contour is precisely manufactured and the fibre material is laid over it, allowing the inner contour to indirectly define the outer surface tolerance. This inversion transfers the precision requirement from the outer face to the inner contour, which can be more easily controlled during manufacturing.
Solution Approach 2:
The inner contour acts as a precise template or copy that defines the desired outer geometry. By creating a high-precision inner mandrel and using it as a form, the outer surface of the cured component automatically replicates the inner contour's geometry. This copying approach allows tolerance control through the mandrel rather than through direct control of the outer surface during the bandaging process.
2Ease of manufacture
If tolerance variations on the inner contour are greater, then ease of manufacture improves, but the outer skin smoothness may be affected
Solution Approach 1:
The patent decouples the tolerance requirements by inverting the control mechanism. The inner contour can have greater tolerances because it serves as a form rather than a final surface. The outer skin smoothness is controlled by the precision of the inner contour's shape, not by tight tolerances on all dimensions. This allows manufacturing flexibility on the inner contour while maintaining outer surface quality.
Solution Approach 2:
The patent applies different quality requirements to different parts of the component. The inner contour requires precision in its overall shape and form to define the outer geometry, but can have greater tolerances in dimensional variations. The outer surface requires high smoothness and tolerance control. This local differentiation of quality requirements allows the inner contour to be manufactured more easily while still achieving the desired outer skin quality.
3Productivity
If fuselage segments are joined with tolerance variations on the outer face, then productivity improves, but aerodynamic performance deteriorates
Solution Approach 1:
The patent inverts the tolerance control approach so that the inner contour, rather than the outer face, is the primary reference for joining. Since the inner contour defines the outer geometry, components can be joined based on inner contour alignment, which is more forgiving and easier to manufacture. The outer skin smoothness is automatically maintained because it is derived from the inner contour form, not directly controlled during joining.
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
This approach ensures that fuselage segments can be joined with precise outer contours, minimizing the impact of inner contour tolerance variations and enhancing aerodynamic performance by producing high-quality fibre-composite materials with controlled tolerances.
Implementation Method 1
curing of a matrix of the fibre material to form the component
Data Source
AI summary
A method and apparatus for producing a hollow component, in particular in the field of aviation or aerospace, including the following steps: provision of an inner contour closed along its circumference; laying of a fiber material over the inner contour; and curing of a matrix of the fiber material to form the component.