Large scale fused-granular-fabrication using recycled carbon fibre/PEKK-PEEK pellets derived from aerospace prepreg waste
Bibliographic record
Abstract
ABSTRACT The manufacturing of thermoplastic unidirectional prepreg rolls involves trimming the edges as they do not meet specifications in terms of thickness and fibre content. This production waste, referred to as tape edge trim (TET), is recycled and transformed into pellets to be used as a feedstock for fused-granular-fabrication (FGF). In the transformation of the TET waste into pellets, neat PEEK polymer is added to the CF/PEKK TET to reduce the fibre content and improve the printability of the material. A large scale six-axis FGF printing robot is employed to print boxes from the recycled and virgin pellets. DSC analyses performed on recycled and virgin pellets reveal the degradation of PEEK and PEKK following aging at 380 °C or 400 °C under oxidative conditions, due to crosslinking reactions. However, no degradation is observed for specimens manufactured by FGF. As commonly observed for parts manufactured using extrusion-based techniques, the standard tensile and flexural specimens extracted from the FGF boxes demonstrate anisotropic mechanical properties. Additional boxes are manufactured by FGF using pellets obtained from shredded FGF box fragments to assess the capability of recycling the material a second time. A reduction of the stiffness and strength of the material is shown for this second recycling, which is assumed to be due to polymer chain scission and reduction in fibre length occurring during the shredding of the printed parts.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".