Thermoplastic Composite Ply Drop-off Alignment for Weld-Free Connection
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Solution Overview
Problem
The structural integrity of thermoplastic composite products manufactured by connecting two components using laser welding is often inferior due to misalignment of fiber layers and difficulty in controlling the depth of recesses, leading to reduced strength at the connection points.
Innovation Solution
The method involves forming ply drop-offs by laterally offsetting plies within each component's stack before consolidation, allowing the plies to define the connection points instead of relying on post-consolidation mechanical operations, and using a two-step thermal process with simultaneous pressure to enhance the connection strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser welding is used to connect thermoplastic composite components, then the components can be joined together, but the structural integrity and strength at connection points deteriorate due to misalignment of fiber layers and difficulty in controlling recess depth
Solution Approach 1:
The ply drop-offs are formed during the consolidation process itself, before the components need to be connected. By pre-positioning the plies with lateral offsets and consolidating them to create the stepped structures, the alignment is ensured beforehand, eliminating the need for post-consolidation laser welding and the associated misalignment problems.
Solution Approach 2:
The patent replaces the laser welding process with a mechanical/thermal consolidation process. Instead of using laser beams to melt and join materials after consolidation, the invention uses the consolidation process itself to create the connection geometry, substituting a more reliable thermal-mechanical process for the less reliable laser welding.
2Strength
If plies are laterally offset to form ply drop-offs, then proper alignment and connection strength are improved, but the manufacturing process complexity increases
Solution Approach 1:
The invention merges two operations into one: the formation of ply drop-offs and the consolidation process are combined into a single step. By incorporating the lateral offsetting and consolidation into one operation rather than separate steps, the process complexity is managed while achieving proper alignment for strong connections.
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 improves the strength and efficiency of the connection between thermoplastic composite components by ensuring proper alignment and fixation of fiber layers during the consolidation process, eliminating the need for laser welding and reducing thermoplastic material loss, thereby enhancing the structural integrity of the final product.
Implementation Method 1
the thermoplastic material of the ply stack is brought to a temperature above the melting point of the thermoplastic material. Due to the melting of the thermoplastic material, the fibers will be supported by a single substantially integral body of the thermoplastic material.
Implementation Method 2
pressure is simultaneously exerted onto the ply stack. After having arranged the ply stack in between the molds, the molds are moved towards each other for exerting pressure on the ply stack while simultaneously heating the ply stack.
Data Source
AI summary
A method for manufacturing a thermoplastic composite product includes: providing a first and second thermoplastic composite component made from a consolidated stack of thermoplastic composite plies, said first and second component having a first and second ply drop off, respectively. The first and second components are positioned such that the first ply drop off and the second ply drop off are aligned, and the first and second components are fixedly connected by means of heating. The stacks of plies for the first and second components are constructed by stacking the plies in a stacking direction wherein the plies are arranged such that plies at a different position along the stacking direction are laterally offset relative to each other for the purpose of forming the first ply drop off and the second ply drop off, respectively, before consolidating.