The invention relates to the technical field of precision
machining, in particular to a compensation method for
thermal deformation of an
aviation large-size workpiece, which comprises the following steps of: firstly, establishing a first mapping relation between the
size change of a calibration piece at different temperatures and the temperature through a
thermal deformation calibration experiment; then, by taking the experimental data as a reference, correcting a
thermal expansion coefficient in the calibration piece
simulation model through an optimization
algorithm, and establishing a high-precision prediction model for deformation of the workpiece to be machined; in the actual
machining process, real-time temperature
field data are collected through a temperature sensor arranged in a key area of a
machine tool, and the
thermal deformation error of a workpiece to be machined and the thermal offset of the original point of a
machining coordinate
system are predicted through the prediction model; and finally, according to a prediction result, a machining track is compensated in real time by dynamically offsetting a machining coordinate
system and modifying the scaling ratio of each axis of a
numerical control system. According to the method, the problem that under the non-constant-temperature working condition, machining is out of tolerance due to thermal deformation of the
aviation large-size workpiece is effectively solved, and the machining precision and the percent of pass are remarkably improved.