Non-Circular Composite Tripod Tube Manufacturing
Solution Overview
Problem
Current manufacturing technologies for tubular elements, such as pultrusion and wrapping, are limited in producing non-circular cross-sections with complex geometries, leading to high reject rates, aesthetic issues, and difficulty in maintaining thickness and rigidity, especially for larger diameters and complex shapes required in modern camera tripods.
Innovation Solution
A discontinuous construction method using a triaxial braided sleeve of carbon fibre, combined with resin transfer moulding (RTM) technology, allows for the production of tubular elements with non-circular cross-sections, incorporating features like thickened portions and complex geometries, while ensuring high axial and torsional rigidity and a consistent thin thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pultrusion or wrapping technologies are used to manufacture tubular elements, then continuous production with good repeatability of dimensional and aesthetic requirements is achieved, but the cross-section is limited to simple circular or semicircular shapes without deep convexities and concavities
Solution Approach 1:
The mandrel is pre-shaped with the desired complex non-circular cross-section geometry before the lamination process begins. This preliminary preparation of the mandrel allows the subsequent fiber layers to conform to complex geometries including deep convexities and concavities, enabling versatility in cross-section design while maintaining continuous production capability
Solution Approach 2:
A mandrel serves as an intermediary tool that enables the production of complex cross-sections. The mandrel acts as a temporary support structure with the desired final geometry, allowing fibers to be deposited in conformal layers that match the complex shape, thereby bridging the gap between simple production processes and complex geometric requirements
2Weight of moving object
If thin wall thickness (about one millimetre) is used to meet lightness requirements, then weight is reduced, but maintaining axial and torsional rigidity and resistance to localized compressive stresses becomes difficult
Solution Approach 1:
Different fiber orientation angles are used in different regions of the tubular element wall. By varying the winding angle of fiber layers through the wall thickness, the structure achieves optimized local properties: higher rigidity where needed while maintaining thin overall thickness for weight reduction. This local variation in fiber orientation allows simultaneous satisfaction of lightness and strength requirements
Solution Approach 2:
Multiple fiber layers with different orientations are combined to create a composite structure that achieves superior mechanical properties at thin wall thickness. The combination of layers with different fiber angles (including longitudinal, helical, and cross-ply orientations) provides synergistic reinforcement that maintains axial and torsional rigidity while keeping the wall thin for weight reduction
3Strength
If multiple fiber layers with different orientations are deposited to guarantee axial and torsional rigidity, then mechanical performance is improved, but the manufacturing process complexity increases
Solution Approach 1:
The fiber winding angle is dynamically adjusted during the lamination process to achieve the desired multi-directional reinforcement. By continuously varying the winding angle through the wall thickness, the process automatically creates the complex multi-layer fiber architecture needed for optimal axial and torsional rigidity, reducing the need for manual intervention and simplifying process control
Solution Approach 2:
The winding angle parameter is systematically varied through the wall thickness to achieve different fiber orientations in successive layers. This parameter change approach allows automated control of fiber placement, creating complex multi-directional reinforcement patterns through a controlled variation of a single parameter (winding angle) rather than requiring complex multi-parameter control
4Productivity
If fixed mandrels are used for pull-winding, then simple circular cross-sections are produced efficiently, but non-circular cross-sections with complex geometries cannot be manufactured
Solution Approach 1:
The mandrel is pre-configured with the specific non-circular cross-section geometry required for each product variant. This preliminary shaping of the mandrel allows efficient continuous production of complex geometries by simply changing the mandrel, rather than changing the entire production process, thereby maintaining productivity while achieving versatility
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 method enables the production of tubular elements with improved rigidity, aesthetic finish, and economic competitiveness, capable of handling complex geometries and varying sizes, reducing reject rates and assembly complexities, and optimizing weight and lightness requirements.
Implementation Method 1
A discontinuous construction method using a triaxial braided sleeve of carbon fibre, combined with resin transfer moulding (RTM) technology
Implementation Method 2
an intermediate double layer 2 of fibres wound in two opposite helical with directions, an angle of approximately +/−30° with respect to the longitudinal axis
Data Source
AI summary
Process for manufacturing a tubular element of composite material with non-circular cross-section including the following steps: (a) pre-production of a semi-finished product of reinforcing fibre braided sleeve (10); (b) insertion of said braided sleeve (10) onto a support mandrel (M) which outer cross-section corresponds to the inner non-circular cross-section of said tubular element; (c) resin-impregnation and polymerization of said braided sleeve (10) on the mandrel (M) in a mould which inner cross-section corresponds to the outer non-circular cross-section of said tubular element; and (d) extraction of the thus obtained tubular element with non-circular cross-section from said support mandrel (M); and tubular element of composite material with non-circular cross-section obtained by said process.