1. Real-time thermal error prediction model for CNC lathes using a new one-dimension lumped capacity method.
- Author
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Li, Tie-jun, Zhao, Chun-yu, and Zhang, Yi-min
- Subjects
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SPINDLES (Machine tools) , *NUMERICAL control of machine tools , *SCREWS , *PREDICTION models , *LATHES , *ENTHALPY , *TEMPERATURE sensors , *TEMPERATURE distribution - Abstract
The axial thermal errors of CNC lathes are mostly caused by the thermal deformation of the screw and spindle. It is necessary to establish a prediction model to evaluate the thermal error distribution of CNC lathes. First, a new real-time virtual frictional heat model under the time-varying working speed of various kinematic pairs in the screw and spindle systems was proposed using the real-time torque current. Furthermore, a novel one-dimension lumped capacity method, which can be used to determine the temperature field rapidly, was proposed, considering the sensitiveness of the temperature of the measuring point with the heat generation rate. By an inverse FEM thermal-solid method of screw and spindle systems, the friction heat distribution and sensitiveness of the temperature of the measuring point with the heat generation rate were obtained. Consequently, based on the one-dimension lumped capacity method, the real-time thermal error prediction model was established, which is used to predict the temperatures and axial thermal errors of the screw and spindle of the machine tools. From the FANUC digit control system, the servomotor torque currents of the screw and spindle and the position of the moving-nut were read and used as inputs by the FOCAS library function. The effectiveness of the proposed prediction model of thermal errors is verified through the experimental and FEM results. This method uses the servomotor torque current collected by the FOCAS library function to determine the heat boundary condition. It can quickly and accurately determine the thermal errors without requiring additional temperature sensors. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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