Closed-loop form error measurement and compensation for FTS freeform machining

To improve fast-tool-servo (FTS) freeform machining accuracy, a closed-loop FTS system is developed with functional modules including toolpath generation, on-machine surface measurement, machining error mapping and compensation. A surface characterisation toolkit was identified and integrated into the processing chain to realise in-process inspection and fast quality control. Surface sampling and reconstruction strategies and robust surface filtration algorithms are adapted to regulate the data flow for both freeform surface characterisation and the optimisation of compensation toolpath from machined error maps. The performance of the developed system is demonstrated by successfully generating three typical freeform surfaces with improved form accuracy by 50%.