TITLE:
Characterization of the Pultrusion Process for Graphite/BMI Composites: A Review of Experimental Methods, Industrial Practices, and Optimization Strategies
AUTHORS:
Kok Toong Leong
KEYWORDS:
Pultrusion, BMI Composites, Graphite Fibers, Process Characterization, Digital Twin, Sustainable Composites, Manufacturing Optimization
JOURNAL NAME:
World Journal of Engineering and Technology,
Vol.14 No.1,
January
9,
2026
ABSTRACT: Pultrusion remains one of the most efficient continuous manufacturing processes for producing high-strength, fiber-reinforced polymer composites. This review examines the pultrusion of graphite/Bismaleimide (BMI) systems by integrating three decades of research—from early experimental characterization to modern advances in process modeling, automation, and material sustainability. The analysis compares pultrusion with alternative composite manufacturing routes and consolidates best practices for achieving thermal and mechanical stability. Experimental foundations from Leong (1990) and the subsequent NASA-supported work by Vaughan and collaborators (1991-2013) are revisited alongside recent developments in digital-twin simulation, adaptive die control, and recyclable resin chemistries (2015-2025). Persistent challenges in resin-flow uniformity, die-heating optimization, and void control are identified, and their mitigation through intelligent process design is discussed. The synthesis highlights how automation, AI-assisted monitoring, and sustainable BMI analogues are transforming pultrusion from a semi-empirical process into a predictive, energy-efficient, and environmentally responsible manufacturing platform. Recommendations for future research emphasize deeper integration of data-driven control, advanced resin systems, and multi-physics modeling to enhance reliability, performance, and sustainability in next-generation composite structures.