Thin-walled parts are widely used in aeronautical, aerospace and automotive applications due to their high performance-to-weight ratio. The thin walls in these parts also lead to low rigidity during machining, making them susceptible to deformation under the influence of the cutting force and/or the clamping force. As a result of spring-back effect after machining, significant machining error occurs in the thin-walled workpiece in its stress-free state. Analytical solution and FEM analysis of the deformation phenomenon are not robust against various machining conditions. To address this issue, a comprehensive error compensation scheme is proposed to predict and compensate for three major error sources, i.e. geometric error, thermal error, and force-induced error. The geometric and thermal errors of the machine tool are modeled and compensated to provide high motion precision for on-machine measurement. The force-induced error is obtained using on-machine measurement data. Comprehensive compensation of all three error sources is achieved by transforming individual compensation values into the same coordinate system. A real-time compensation system is developed based on the numerical control system of the machine tool. Compensation experiments carried out on two types of thin-walled parts show (i) a reduction of machining errors by at least 74% and (ii) an improvement of machining productivity by at least 41%, which validates the proposed compensation scheme.

High-end CNC machine tools are key equipment supporting machining of the parts in aviation, aerospace and energy engineering fields. At present, China has been able to design and manufacture various types of high-end machine tools, but there are still performance gap compared with foreign advanced products. A major gap is the dynamic error at high speed. Dynamic error is defined as the deviation from the effector end position to the setpoints position, which is urther divided into the dynamic error inner servo-loop and dynamic error outer servo-loop. By measuring and separating dynamic error of a domestic machine tool, the forms of the two components of the dynamic error can be presented. On this basis, special analysis on the causes of all kinds of the forms of the dynamic errors are conducted. In addition, the critical technologies of dynamic error at home and abroad are summarized. Finally, the research directions that needs focus in China around dynamic error are proposed.

Gears are important basic parts in aerospace and other fields, as well as their processing quality is affected by the thermal characteristics of the machine tool. In order to explore the thermal state of the green dry hobbing machine, an identification method of temperature field characteristic combining multi-field coupling simulation and thermal imaging reconstruction is proposed. Based on the characteristics analysis of the multi-source heat flow of the dry hobbing machine, the temperature field simulation model of the dry hobbing machine with the coupling of structure-heat-fluid multiphysics is established. Then, combining thermal image reconstruction and simulation analysis, the temperature field distribution characteristics of dry hobbing machine are revealed and its key thermally sensitive parts are determined. On this basis, a multi-dimensional optimization strategy for temperature field distribution of dry hobbing machine is proposed. The results can provide theoretical support for the thermal balance design and thermal error compensation of dry hobbing machine.