Understanding Part Fabrication Errors in Closed-Loop Machining Systems

摘要

This paper clarifies the relationships between different types of part errors involved in error compensation for closed-loop machining. Measurement error (i.e., inaccuracies due to operator performance, or to the geometry, action, response, or repeatability of measurement instrumentation, etc.) are not within the scope of the discussion, with the exception of machine tool geometric errors. The paper uses diagrams, equations, software engineering modeling techniques, and exposition to describe the relationships between the different types of part errors. One benefit is to enhance the understanding of part error data to facilitate the development of error compensation algorithms and related software. Another benefit is to provide a way to organize the representation of error and error compensation data for closed-loop machining systems. The paper addresses a scenario with a closed-loop machining system that includes a machine tool, nominal part design and inspection data, a geometric-thermal (GT) model of the machine tool, process-intermittent error compensation capability with an on-machine dimensional inspection probe, a coordinate measuring machine (CMM), and other features.