Advances in micromilling: physical effects, sustainability, hybrid processes, and digital intelligence

Micromilling is a high-precision microfabrication process capable of producing complex geometries and functional surfaces with submicron accuracy across a wide range of engineering materials. Although numerous review studies have addressed specific aspects of micromilling, including cutting mechanics, surface integrity, sustainability, hybrid manufacturing, and intelligent production systems, a comprehensive framework integrating these perspectives remains lacking. This study presents a Bibliometric-Systematic Literature Review to identify current developments, emerging trends, industrial applications, and future research directions in micromilling. The analysis reveals significant advances in understanding key physical phenomena, such as minimum chip thickness and Specific Cutting Energy, as well as the growing adoption of hybrid-assisted processes that involve ultrasonic, laser, plasma, and electrochemical technologies. Recent developments in sustainable manufacturing, functional surface texturing, biocompatible applications, and energy-efficient machining are also highlighted. Furthermore, the review demonstrates the increasing role of Artificial Intelligence and Digital Twins in process monitoring, optimization, prediction, and adaptive control. Based on the identified research landscape, an integrated framework is proposed that connects physical mechanisms, sustainability principles, hybrid manufacturing technologies, and digital intelligence. The findings indicate that the future of micromilling lies in the convergence of these domains, enabling more precise, sustainable, adaptive, and industrially scalable microfabrication systems.