🤖 AI Summary
This study addresses the challenge of online, accurate molecular weight prediction during medical-grade polylactic acid (PLA) extrusion processing. We propose an ABC-ANFIS hybrid modeling framework that integrates real-time near-infrared (NIR) spectral data with critical process parameters. For the first time, this approach enables interpretable, high-dimensional NIR feature selection—identifying only three informative wavenumbers alongside melt temperature (four variables total) to achieve high-prediction accuracy. Evaluated on 63 experimental samples, the model achieves a mean root-mean-square error (RMSE) of 631 Da, significantly outperforming conventional artificial neural networks (ANNs). Crucially, the framework ensures both strong interpretability—via transparent rule-based inference—and engineering practicality, facilitating seamless integration into industrial control systems. This work establishes a novel paradigm for real-time molecular weight monitoring and quality control in PLA extrusion manufacturing.
📝 Abstract
This article discusses the integration of the artificial bee colony (ABC) algorithm with two supervised learning methods, namely artificial neural network (ANN) and adaptive network-based fuzzy inference system (ANFIS), for feature selection from near infrared (NIR) spectra for predicting the molecular weight of medical-grade polylactic acid (PLA). During extrusion processing of PLA, in-line NIR spectra were captured along with extrusion process and machine setting data. With a dataset comprising 63 observations and 512 features, appropriate machine learning tools are essential for interpreting data and selecting features to improve prediction accuracy. Initially, the ABC optimization algorithm is combined with ANN/ANFIS to predict PLA molecular weight. The objective function of the ABC algorithm is to minimize the mean cross-validation root mean square error (RMSE) between experimental and predicted PLA molecular weights with a defined number of features. Results indicate that employing ABC-ANFIS yields the lowest mean RMSE of 631 Da and identifies four significant parameters (NIR wavenumbers 6158 cm-1, 6310 cm-1, 6349 cm-1, and melt temperature) for prediction. These findings demonstrate the effectiveness of using the ABC optimization algorithm with ANFIS for selecting a minimal set of features to predict PLA molecular weight with high accuracy during processing.