Joining Processes for Fibre-Reinforced Thermoplastics: Phenomena and Characterisation
Abstract
:1. Introduction
- I
- : Process temperatures above the melting temperature lead to independent matrix flow phenomena through the fibres (Figure 1, percolation, squeeze flow) and enable reorientations of the fibres in the surrounding matrix. As a result, the occurrence of fibre failures and cracks in the TPCs during forming can often be avoided.
- II
- : Process temperatures below the melting temperature of the matrix inhibit the flow processes of the matrix (e.g., matrix percolation). When the temperature of the joining process is very low, the TPC behaviour is more brittle, caused by the supporting effect of the matrix. This can lead to fibre failures and cracks in the joining zone [24]. With rising temperature, the ductility of the matrix increases, while the supporting effect for the fibres decreases. Therefore, TPC sheets are often formed above the Vicat softening temperature to enable joining by plastic deformation. The fibres and the matrix can still not move independently. Squeeze flow occurs without percolation and can be described as a yielding.
- For the embedding of inserts, the process temperature is above the melting temperature of the matrix (Temperature Section I) and an isothermal mould is used.
- Moulding of contour joints is also carried out above the melting temperature of the matrix (Temperature Section I), but in a variothermal mould.
- The hotclinching, on the other hand, is performed below the melting temperature of the matrix (Temperature Section II) using a variothermal mould.
2. Materials and Methods
2.1. Material Specification
2.2. Joining Processes
2.2.1. Embedding of Inserts
2.2.2. Moulding of Contour Joints
2.2.3. Hotclinching
2.3. Evaluation Methods
3. Process Phenomena
3.1. Embedding of Inserts
3.2. Moulding of Contour Joints
3.3. Hotclinching
4. Discussion
5. Conclusions
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
Abbreviations
CF | Carbon fibre |
CT | Computed tomography |
FVC | Fibre volume content |
GF | Glass fibre |
LI | load introduction |
PP | Polypropylene |
PA6 | Polyamide 6 |
TPC | Thermoplastic composites |
UD | Unidirectional |
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Embedding of Inserts | Moulding of Contour | Joints Hotclinching | ||
---|---|---|---|---|
TPC | Material | GF-PP | CF-PA6 | GF-PA6 |
Name | Celstran® CFR-TP PP-GF70 | Celstran® CFR-TP PA6 CF60-03 | Tepex® dynalite 102-RGUDm317(8)/47% | |
Configuration | UD [(0°/90°)4]S | [±30°2/0°7/±30°2/±70°5] | UD [(0°/90°)4]S | |
FVC | 45% | 48% | 47% | |
Thickness | 4.3 mm | 2 mm | 2 mm | |
Melting temperature | 173 °C | 220 °C | 220 °C | |
Tensile modulus (UD 0°) | 34 GPa | 100 GPa | 33.6 GPa (1) | |
Tensile strength (UD 0°) | 0.9 GPa | 1.9 GPa | 0.6 GPa (1) | |
Metal | Material | steel 1.2210 | EN AW-6060 T4 | EN AW-6016 T4 |
Thickness | 4.3 mm | 2 mm | 1.5 mm | |
Outer diameter | 12 mm | |||
Young’s modulus | 210 GPa | 68 GPa | 70 GPa | |
Tensile strength | 0.7 GPa | 0.15 GPa | 0.12 GPa |
Embedding of Inserts | Moulding of Contour Joints | Hotclinching | |
---|---|---|---|
X-ray voltage | 80 | 160 | 100 |
Tube current | 250 | 160 | 220 |
Exposure time | 2000 | 500 | 500 |
X-ray projections | 2880 (8 per 1°) | 1440 (4 per 1°) | 1440 (4 per 1°) |
Voxel size | 8 |
Elongation | Transverse Compaction | Bending | Torsion | Shifting | |
---|---|---|---|---|---|
Embedding of Inserts | n.a. | Occurring | Occurring | n.a. | Occurring |
Moulding of Contour Joints | n.a. | Occurring | Occurring | n.a. | Occurring |
Hotclinching | n.a. | Occurring | Occurring | Occurring | Occurring |
Percolation through and along Fibres | Squeeze Flow | Deconsolidation | |
---|---|---|---|
Embedding of Inserts | Occurring | Occurring | Occurring |
Moulding of Contour Joints | Occurring | Occurring | Not occurring |
Hotclinching | Not occurring | Occurring | Not occurring |
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Troschitz, J.; Gröger, B.; Würfel, V.; Kupfer, R.; Gude, M. Joining Processes for Fibre-Reinforced Thermoplastics: Phenomena and Characterisation. Materials 2022, 15, 5454. https://doi.org/10.3390/ma15155454
Troschitz J, Gröger B, Würfel V, Kupfer R, Gude M. Joining Processes for Fibre-Reinforced Thermoplastics: Phenomena and Characterisation. Materials. 2022; 15(15):5454. https://doi.org/10.3390/ma15155454
Chicago/Turabian StyleTroschitz, Juliane, Benjamin Gröger, Veit Würfel, Robert Kupfer, and Maik Gude. 2022. "Joining Processes for Fibre-Reinforced Thermoplastics: Phenomena and Characterisation" Materials 15, no. 15: 5454. https://doi.org/10.3390/ma15155454