Nonlinear prediction and analysis of the precision remaining useful life of the key meta-action unit of CNC machine tools with incomplete maintenance

•Considering CNC machine tool's dynamic life cycle, a more reasonable analysis object (key meta-action unit) is selected.•The KMAU precision degradation process is considered non-linear and uncertain, with online parameter updates based on Bayesian principle.•The GPIM improves the composite NHPP model for describing the precision changes of KMAU with incomplete maintenance.