Study on Suppression of Toolpath Boundary Steps in Face Milling

The downsizing of machine tools has progressed in response to demands for flexible production systems, reduced machining costs, and lower environmental impact. However, such downsizing inevitably results in reduced structural rigidity and increased reliance on small-diameter cutting tools. In face milling operations, this trend necessitates multi-pass machining rather than conventional single-pass processing, leading to the formation of steps and surface patterns at tool path boundaries. These boundary steps markedly degrade surface integrity and have emerged as a critical issue under increasingly stringent surface quality requirements. This study experimentally investigates the relationships between machining parameters and the surface patterns and step heights generated at tool path boundaries in face milling. The dominant factors influencing boundary step formation are systematically identified through controlled cutting experiments. Based on these findings, a database of machining parameters is developed with the aim of suppressing or completely eliminating boundary steps. At this stage of the research, particular emphasis is placed on understanding boundary step formation, with the ultimate objective of achieving step-free face-milled surfaces suitable for high-precision components.