Thermoplastic Composite Joining via Rotating Needle Insertion
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Solution Overview
Problem
Existing methods for joining thermoplastic composite materials often weaken the reinforcing fibers and are not easily testable, as they require drilling or use of fasteners that generate heat, damaging the fibers and creating hidden connections.
Innovation Solution
The method involves using needles inserted under pressure and rotation into the thermoplastic matrix material, which softens and solidifies, allowing for a strong connection without fiber damage, with preferred angled and corrugated needles and additional thermoplastic welding for enhanced strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If drilling is used to join thermoplastic composite materials, then fastening is achieved, but the matrix material is heated by frictional heat and reinforcing fibers are severed
Solution Approach 1:
The patent replaces the drilling mechanical system with a needle insertion system. Instead of using rotating drills that generate frictional heat and sever fibers, the invention uses needles that are pressed and rotated at low speed to insert through the matrix material, significantly reducing fiber damage while achieving secure fastening through the needle's anchoring effect in the thermoplastic matrix.
Solution Approach 2:
The patent changes the operational parameters of the fastening process by using low rotational speed and controlled pressure application. This allows the needle to penetrate the thermoplastic matrix without generating excessive frictional heat that would damage the reinforcing fibers, thereby maintaining the structural integrity of the composite material while achieving secure joining.
2Reliability
If adhesive bonding is used to join components, then permanent connection is achieved, but the bond is hidden and difficult to inspect
Solution Approach 1:
The patent introduces a visible needle as an intermediary element that provides both mechanical fastening and visual inspection capability. The needle acts as a mediator that combines the hidden reliability of permanent connection with the visibility needed for inspection, allowing observers to directly see the fastening element and assess the quality of the joint without relying on indirect inspection methods.
3Strength
If self-tapping screws are used, then fastening is achieved, but prior drilling is required which weakens the fiber material
Solution Approach 1:
The patent extracts the harmful drilling step from the fastening process. By using needles that can be directly inserted without prior drilling, the invention removes the source of fiber material weakening while maintaining the fastening function. The needle design allows direct penetration and anchoring in the thermoplastic matrix without requiring pre-drilled holes that would sever reinforcing fibers.
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 enables permanent joining of thermoplastic composite materials without weakening the fibers, providing a visible and reliable connection with improved mechanical properties and reduced deformation.
Implementation Method 1
setting the needle into a rotational movement so that the thermoplastic matrix material softens due to friction
Implementation Method 2
the thermoplastic matrix material softens due to friction and is pushed through the softened matrix material
Implementation Method 3
solidifying the thermoplastic matrix material
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
The invention relates to connected components made of thermoplastic fibre-composite materials, said components being connected by pins that are introduced under pressure and rotation into the resultantly pliable matrix material of the components, and also relates to a method for connecting components of this type.