Thermal errors caused by spindle rotation is a major factor that influences the precision stability of CNC machine tools. To determine an effective method for reducing thermal errors, a thermal experiment was carried out on the spindle of a vertical drilling center. The thermal deformation mechanism and thermal error variations of the spindle are presented. Based on the generation, convection, and conduction theory of heat, the thermal field model of a spindle system is derived. The relationship between the thermal field and the radial thermal error is established using a physically based method. Finally, the effect of the thermal error model proposed is verified by both a simulation and experiment. The results recorded on the two CNC machining centers indicate that the average fitting accuracy of the theoretical model is up to 94.1%, which validates the high accuracy and strong robustness of the presented model.

To eliminate the influence of thermally induced error from a machine tool on machining accuracy, a comprehensive error compensation method for thermal displacement of the screw shaft and spindle is put forward. Based on a heat transfer mechanism and experimental analysis, a model of screw thermal expansion error is built. Modeling of spindle thermal growth that depends on speed variations is also proposed. Thermal tests for studying thermal behavior of the spindle and screw axis are carried out on the vertical drilling center TC500R. Finally, the compensation effect of the robust model is validated via experimental tests and machining. Experimental results show that thermal displacement variations are controlled within 2 μm when the compensation system is activated. The suggested model can achieve high accuracy and good applicability in different moving states. Machining results indicate that dimensional accuracy of the workpiece is significantly improved after implementation of compensation. Feasibility of the thermal error compensation system is satisfactory in applications for drilling operations.

This paper mainly focuses on the numerical simulation of particles trajectories aiming at obtaining the movement regulations of particles with different diameters. The article takes advantage of random orbital model of phase coupling under Lagrange coordinate, and figures out that the movement of small particles has large randomness, meanwhile particles with the same diameter and different initial positions can reach various final positions, some of which can escape or be captured from the exhaust pipe. Particles trajectory can be different even if it has same diameter and initial position. The conclusion of this thesis also puts forward that three different phenomena of presentation of gray ring, short-circuit of exhaust pipe and back-mixing of dust exhaust can appear under any conditions. Almost all large particles can be captured by the cyclone separator, and few particles show retention and short time rotation in the lower part of exhaust pipe.

This article sets up the equations of material in the horizontally circle vibrating drier. According to basic theories of hydrodynamic and vibration, which gets the operating period and time expression of the material on the single hole panel of drier. According to equations, model erected on the computer simulate operating time of the material in the random position of the drier. The imitating data can match practical ones very well.

This paper mainly deals with pressure situation in cyclone aiming to obtain the pressure distribution and pressure drop in cyclone separation by taking advantage of the model of RSM of software Fluent, and put forward that the total pressure of import part is the highest and the minimum total pressure locates inside exhaust pipe in cyclone. Static pressure of outside swirl is relatively higher than the inner swirl, and the minimum static pressure occurs in the axis of the separator extending into the dust hopper. Relationship of pressure distribution and particles separation can be obtained according to the analysis, which can provide the theoretical basis for further enhancement of performance and structure optimization.