Inductive Heating Pultrusion for Composite Friction Reduction
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Solution Overview
Problem
Existing pultrusion methods for manufacturing fibre-reinforced composite products face challenges such as high friction, limited production speed, fibre damage, and difficulties in achieving uniform heating, leading to suboptimal product quality and increased costs due to complex friction reduction measures.
Innovation Solution
A pultrusion method involving inductive heating of a preform to the processing temperature of the thermoplastic matrix material before consolidation, which reduces friction and allows for rapid, uniform heating without surface contact, combined with pre-compaction and consolidation using multiple dies to control cross-sectional dimensions and prevent fibre jamming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the braid is pulled through a heated die for consolidation, then the composite product can be formed, but friction increases leading to fibre damage and deformation
Solution Approach 1:
The preform is pre-compacted in a first die before heating and consolidation in a second die. This preliminary compaction reduces the volume and adjusts the cross-sectional dimensions of the preform, allowing it to pass through the consolidation die with reduced friction and without causing fibre jamming or deformation.
Solution Approach 2:
The consolidation process is divided into two separate stages: pre-compaction in a first die, and consolidation in a second die. This segmentation allows each die to perform its specific function optimally - the first die reduces volume and prepares the preform, while the second die performs the actual consolidation at processing temperature, thereby reducing friction and fibre damage.
2Temperature
If the braid is heated by surface contact with a heated die, then the matrix material can be melted for consolidation, but heating is slow and non-uniform
Solution Approach 1:
Conductive heating through die contact is replaced with inductive heating using an induction coil. The induction coil generates a magnetic field that induces eddy currents within the preform, causing internal heating through resistive heating. This substitution enables rapid, uniform heating throughout the preform volume without relying on slow surface-to-core heat conduction.
Solution Approach 2:
The heating method is changed from conductive (contact-based) to inductive (electromagnetic field-based). This parameter change transforms the heating mechanism from external surface heating to internal volumetric heating, dramatically increasing heating speed and uniformity while enabling faster processing cycles.
3Manufacturing precision
If the preform is compacted before heating, then cross-sectional dimensions can be controlled, but fibre jamming may occur upstream of the die
Solution Approach 1:
The preform is pre-compacted in a first die at ambient or low temperature before being heated and consolidated in a second die. This preliminary compaction at lower temperature reduces the preform volume and sets the cross-sectional dimensions without causing the fibres to become too rigid or jammed, as the matrix material has not yet reached its melting temperature.
Solution Approach 2:
The compaction and consolidation operations are separated into two distinct stages performed in different dies. The first die performs gentle pre-compaction to control dimensions, while the second die performs the actual consolidation at processing temperature. This segmentation prevents fibre jamming by avoiding excessive compaction forces on unheated material.
4Reliability
If complex measures are taken to reduce friction in the die, then fibre damage can be avoided, but device complexity and costs increase
Solution Approach 1:
The preform is pre-compacted to reduce its volume and adjust its cross-sectional dimensions before entering the consolidation die. This preliminary preparation reduces the contact pressure and friction between the preform and the consolidation die, thereby protecting fibres from damage without requiring complex friction reduction mechanisms such as elaborate lubrication systems or cooling arrangements.
Solution Approach 2:
By separating pre-compaction and consolidation into two different dies, the consolidation die operates under more favorable conditions with reduced friction. The pre-compacted preform has smaller cross-sectional dimensions and better contact with the die wall, reducing the risk of fibre damage during consolidation without requiring additional complex measures in the consolidation die.
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 the efficient and reliable production of high-quality fibre-reinforced composite products with reduced friction, improved fibre alignment, and enhanced surface quality, while simplifying the manufacturing process and reducing costs.
Implementation Method 1
the preform is inductively heated to a processing temperature of the thermoplastic matrix material
Implementation Method 2
an induction coil is provided, which surrounds a path of pultrusion and is arranged and adapted for inductively heating the preform as the preform is moved through or past the induction coil
Implementation Method 3
the preform is introduced into a die and, while the preform passes through the die, the preform is consolidated by means of the die
Data Source
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AI summary
Pultrusion methods and arrangements for manufacturing a fibre-reinforced composite product comprising reinforcing fibres embedded in a thermoplastic matrix material are proposed. When carrying out the method, the following is performed along a path of pultrusion (4): providing a preform (19); further downstream, introducing the preform into a first die (55) and pre-compacting the preform by means of the first die while the preform passes through the first die; further downstream, heating the pre-compacted preform (21) to a processing temperature of the thermoplastic matrix material; and further downstream, introducing the preform (39) into a second die (66) and consolidating the preform by means of the second die while the preform passes through the second die. Furthermore, arrangements for manufacturing a fibre-reinforced composite product are proposed.