Tolerance-constrained adaptive machining of negative allowance surface based on composite on-machine measurement
Aiming at the issues of poor dimensional consistency,low profile,and wall thickness forming accuracy of the complex cabin intake port surface,a tolerance-constrained adaptive machining approach for negative allowance surface based on the composite on-machine measurement is proposed.A composite on-machine measurement platform is constructed with the hysteresis effect clarified,and a synchronous data acquisition system is developed.The measurement error is then examined along with a proposed iterative calibration method for laser sensors.Under the guidance of measured profile data,the high-precision ultrasonic on-machine measurement of wall thickness is achieved by accurately solving normal vectors.For machining surfaces with negative allowance,a mathematical model is developed under double constraints of profile and thickness.Additionally,occupancy,non-uniformity,and consistency are defined,and under various weights,a data-driven surface reconstruction is.realized.Experiments are used to develop and validate an on-machine measurement and adaptive machining strategy for the intricate cabin inlet surface.The results demonstrate that the positive and negative errors of the measured profile are+0.0083 and-0.0073 mm,respectively,and the errors of wall thickness are within 0.03 mm.When the surface has a negative allowance of-0.0524 mm,the profile's maximum positive and minimum negative deviations after adaptive machining are+0.0538 and-0.3655 mm,respectively.And the maximum and minimum values of the wall thickness deviation are+0.16 and-0.22 mm,respectively,which satisfy the tolerance requirements and achieve accurate and effective machining of the whole surface.