In this study, the thermal deformation of a machine tool structure due to the heat generated during operation was analyzed, and embedded cooling channels were applied to exchange the heat generated during the operation to achieve thermal error suppression. Then, the finite volume method was used to simulate the effect of cooling oil temperature on thermal deformation, and the effect of thermal suppression was experimentally studied using a feed system combined with a cooler to improve the positioning accuracy of the machine tool. In this study, the supply oil temperature in the structural cooling channels was found to significantly affect the position accuracy of the moving table and moving carrier. If the supply oil temperature in the cooling channels is consistent with the operational ambient temperature, the position accuracy of the moving table in the Y direction and the moving carrier in the X and Z directions has the best performance under different feed rates. From the thermal suppression experiments of the embedded cooling channels, the positioning accuracy of the feed system can be improved by approximately 25.5 % during the dynamic feeding process. Furthermore, when the hydrostatic guideway is cooled and dynamic feeding is conducted, positioning accuracy can be improved by up to 47.8 %. The machining accuracy can be improved by approximately 60 % on average by using the embedded cooling channels in this study. Therefore, thermal suppression by the cooling channels in this study can not only effectively improve the positioning accuracy but also enhance machining accuracy, proving that the method is effective for enhancing machine tool accuracy.

In space, structures encounter various severe environments, including severe thermal conditions. The signal level of the radio wave from the Large Deployable Reflector (LDR) mounted on the Engineering Test Satellite-VIII (ETS-VIII) was observed to change during an Earth eclipse. This phenomenon was assumed to be caused by the thermal deformation of the LDR. Therefore, in this study, a means to suppress the thermal deformation is proposed and demonstrated by focusing on the internal force generated at the springs used to deploy the antenna. According to the numerical results obtained from finite element analyses, the thermal deformations at all apices that support the reflectors were suppressed at a high correction rate by adjusting the coefficients of thermal expansion in the structural members and by controlling spring forces differently in four areas depending on the distances from the constraint point.

To study the thermal deformation behavior and microstructural evolution of the type 347H austenitic steel, compression experiments were conducted at the temperatures of 800–1100 °C with strain rates of 0.01–10 s−1. The activation energy and constitutive equation of the type 347H steel during thermal deformation process were determined according to the flow stress curves. Both the hot processing maps and microstructure characteristics under different deformation conditions were investigated. Based on the thermal processing maps, two unstable regions under 800 °C/0.01–10 s−1 and 1100 °C/0.01 s−1 were identified. The processing maps were in favor of optimizing thermal processing parameters and improving thermal processing properties of the type 347H austenitic steel. After thermal deformation, the dislocation in the austenite matrix increases significantly. Besides, in the stable regions, the precipitation of carbides is facilitated by thermal deformation.