Closed-loop thickness control and sensor placement in extrusion blow moulding
Bibliographic record
Abstract
Extrusion blow moulding (EBM) is a polymer forming technique used to manufacture hollow plastic parts, such as fuel tanks. In this work, the feasibility of using closed-loop control in EBM is explored to compensate for machine drift and disturbances. A control system is proposed to regulate the extrusion process in EBM. The extrusion controller aims to increase process consistency by minimizing part thickness deviations. The thickness of the extrudate is measured during the extrusion cycle and any deviation from the desired thickness profile is compensated by changing the die gap in real time. The controller, which offers flexibility in thickness sensor placement, features a Smith predictor configuration embedding an H∞ controller. It compensates for the input-dependent polymer transport delay, the nonlinear steady-state swell, and nonminimum phase necking effects affecting the extrudate. This extrusion control technique may help reduce the production rate of off-specification parts and improve product quality.
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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 | 0.001 |
| 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".