Inline metrology in composite winding processes – a comprehensive view on state of the art, current developments and perspectives

Composite winding processes offer the possibility to produce lightweight pressure vessels, a key element in hydrogen mobility, with the potential to reduce global carbon dioxide emissions. Digitizing winding processes has significantly gained attention because of the potential to improve the ecological and economic sustainability of both the process and the product. Numerous process parameters influence manufacturing performance and overall sustainability. This necessitates precise parameter adjustment. However, computing process parameters is not trivial and often imprecise, especially with regard to process-related fluctuations. Consequently, inline measurement systems are needed to acquire actual parameter values and enable process simulations, the generation of digital twins, and closed-loop controls. This paper provides an overview of measurement principles and sensors for monitoring composite winding processes, addressing their implementation, as well as studies on their general feasibility and accuracy. Presented are principles for monitoring the input material, fiber tension, temperature, length and speed, as well as methods for acquiring impregnation properties (resin or volatile content), tack, and fiber deposition geometry (winding angle, gaps, overlaps). The review critically compares the methods’ advantages and restrictions concerning inline use in composite winding and assesses their technology readiness levels as well as future potential for industrial inline process monitoring in composite winding. A decision aid is provided for selecting suitable sensor principles according to the targeted process or material parameters. The early publications presented in this overview address simple measurements and date back to the mid-1990s, while data-driven technologies such as artificial intelligence are the subject of current research.