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Calculations of transient thermal loads/boundary conditions are crucial for accurate thermal simulations of motorized spindle unit with time-varying working parameters (such as rotation speed). By the ELM theory, this paper proposes a modeling and calculation method onto transient thermal loads/boundary conditions for spindle simulation, according...
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Generally, the accuracy stability of precision motorized spindle unit is influenced by its structural thermal balance behaviors (power matching degree of spindle structural heat generations - dissipations). For the accurate analysis onto this spindle heat transfer behaviors based on temperature detections, this paper describes a method constructed...
Generally, the accuracy stability of a precision motorized spindle unit is influenced by its structural thermal balance behaviors (power matching degree of spindle structural heat generation–dissipations). For the accurate analysis of this spindle heat transfer behaviors based on temperature detections, this paper describes a method constructed wit...
Citations
... Pressure on the guideway (N) H System heating capacity (W) H f Air convection heat transfer coefficient (W/ (m 2 ·°C)) h 1 Specific enthalpy of the refrigerant vapour at the compressor inlet (J/kg) h 2 Specific enthalpy of the refrigerant at the compressor outlet (J/kg) h 4 Specific enthalpy of the refrigerant vapour at the evaporator inlet (J/kg) K mhp Proportional amplification coefficient of H-t in the main-loop K mrrh Main-loop H-t oil time regulation ratio K mrrl Main-loop L-t oil time regulation ratio K sp Proportional amplification coefficient of the sub-loop K srr Sub-loop time regulation ratio k mh Ratio of the energy transferred to the oil by the H-t oil pump M b ...
... Therefore, it is necessary to develop efficient suppression methods to reduce the thermal errors of precision machine tools. Thermal error modelling and compensation can reduce some thermal deformation errors [2][3][4]. The thermal errors are directly or indirectly measured by various measurement methods and then analysed according to the established compensation model and finally feed back to the CNC system to realize compensation. ...
Variations in running conditions cause fluctuation in the temperature field of precision machine tools, which inevitably results in thermal errors. To meet the demands of dynamic and time-varying temperature control capability, an active temperature control (ATC) method based on time grating principle is proposed, and the ATC system is developed. The ATC system contains main-loop and sub-loops. The oil target temperature in the sub-loop is determined according to the running parameters and the matching principle of the generalized heat generation–dissipation power. In accordance with the time grating principle, dynamic and differential oil temperature control of each sub-loop is achieved via the inlet time regulation of high-temperature (H-t) or low-temperature (L-t) oil in the main-loop. The main-loop H-t and L-t oil target temperatures are determined by the target range of the sub-loop temperature. The dynamic distribution of the refrigeration capacity and proportional heating mode is adopted to control the temperatures of H-t and L-t oil. By focusing on the feed system of precision machine tool, we carry out both dynamic simulation study and verification experiments, and the results show that the ATC method and system can effectively regulate the temperature field of precision machine tools, thus improving the thermal accuracy of the precision machine tool.
... The deformation of the spindle can be reduced between 38 % and 70 % on the Y-and Z-axis. Liu et al. [10] built a transient thermal load model based on heat-fluid-solid coupling FE simulation of a motor spindle. Using extreme learning machine theory, the relationship between the simulated temperatures and the corresponding measured load conditions, as rotational speed and bearing temperatures, was trained in a single hidden layer feedforward neural network. ...
One central aspect of future high speed machining is the knowledge of the thermal behaviour of the machine tool and its motor spindle. A new temperature control for motor spindles with energy efficient synchronous reluctance drive is developed. In the first instance a finite element method model (FEM) is set up. This FEM aims to analyse the use case of nearly constant bearing temperatures within a defined range throughout the machining operation. By means of design of experiments (DOE), selected operating points of the speed-torque-characteristics are simulated with FEM considering different cooling parameters such as volume flow and inlet temperature. Machine learning algorithms are used to model the input-output-relationship in order to reduce the complex thermal motor spindle FEM. The applied algorithms are multiple linear regression and artificial neural network. The concept of temperature strategy, the FEM simulation results and the thermal models using machine learning algorithms are presented.
High-speed motorized spindles play a vital role in manufacturing. In the process of high-speed rotation of the motorized spindle, the built-in motor and the high-speed running bearing will produce a lot of heat, and its heating will seriously affect the machining accuracy of the machine tool and the life of the spindle assembly. Therefore, the research on the thermal characteristics and cooling technology of the high-speed motorized spindle is an important measure to reduce the fire and explosion of the machine tool, improve the stability of the spindle and the safety of the machine tool, and is of great significance to ensure the stable operation of the high-speed motorized spindle. Based on the heat source, this paper puts forward two heating ways of high-speed motorized spindle, including bearing heating and motor heating, and probes into the thermal characteristic mechanism of high-speed motorized spindle and the modeling technology of thermal error compensation of high-speed motorized spindle in detail, and summarizes the bearing cooling technology, the principle, scope of application, advantages and disadvantages of motor cooling technology, and put forward corresponding improvement measures. And the future development of high-speed motorized spindle is prospected, and some new ideas are provided for the improvement of its technology.
The temperature rise of the high-speed motorized spindle directly affects the machining accuracy of the machine tool, making it crucial to accurately understand the dynamic changes in temperature during spindle operation in order to improve machining accuracy. This paper proposes a prediction model for the temperature field of the high-speed motorized spindle, considering both the instantaneous and steady-state phases, to accurately predict the dynamic changes in temperature rise during spindle operation. Initially, the steady-state heat transfer coefficients and the instantaneous heat generation at random moments during spindle operation are optimized using the Grey Wolf Optimization algorithm. Subsequently, a prediction model is established based on the identified instantaneous heat generation, using a BP neural network, to enable full-cycle prediction of the heat generation of the motorized spindle. Finally, experimental verification demonstrates that the proposed prediction model achieves a prediction accuracy of 98%.
The thermal error generated by the high-speed motorized spindle during machining is the main reason for the exactness of the machine tool, so accurate thermal characteristics analysis is essential. In this paper, the experimental platform of motorized spindle was set up to measure the temperature and thermal displacement data at 10000r/min. Secondly, the simulation parameters of A02 high-speed motorized spindle are obtained through theoretical calculation, and the multiphysics simulation model is established. After calculation, the exactness of the temperature field model can reach about 95%, and the exactness of the displacement field can reach 85%, it shows that the simulation model can accurately predict the state of motorized spindle. Finally, a new cooling jacket structure is proposed, and it is found that the optimized temperature is reduced by 32.11% and the thermal displacement of the front surface is reduced by 32.63%. indicating that the improved cooling water jacket has better cooling performance than the traditional cooling water jacket.
The ceramic spindle rotor system is widely used in CNC machine tools. However, the dynamic characteristics are influenced by the magnetic forces and thermal deformation, which leads to the reduction of running accuracy. In this paper, the thermal deformation of the rotor system are calculated, and the magnetic field distribution is obtained based on the Maxwell theory. The thermal magnetic coupling effect is then analyzed to investigate the interaction between thermal deformation and magnetic force, and the impact of thermal magnetic coupling effect on the dynamic characteristics is obtained. Experiments are conducted to verify the simulation results, and the dynamic characteristics with and without consideration of thermal magnetic coupling effect are compared. Results show that the thermal deformation and magnetic force have nonlinear increases with speed, and the model considering the thermal magnetic coupling effect has a higher accuracy with the error decreased by 4%. The air gap is a key factor that determines the dynamic characteristics of the ceramic spindle rotor system, and a larger air gap can help lower the vibration at high speed. This study provides a theoretical basis for the structural design of ceramic spindle rotor system.
