Key Engineering Materials Vol. 693

Abstract: In order to ensure the effect of three types of parameter to HSS tap life, orthogonal experiment with interaction included was applied to accomplish the experiment of W9Mo3Cr4V HHS tap tool life. These parameters are cutting parameter (CP)--tap speed, process parameter (PP) -- temperature of cryogenic treatment, and structure parameter (SP)--rounded cutting edge radius. According to range analysis, the sequence of factors including the individual factors and interaction factors that we obtained is PP, SP, PP×CP, CP, CP×SP, PP×SP, CP×PP×SP. The sequence shows that the former interaction takes part in deciding the optimal factor combination. The optimal combination is CP_2, PP_1, SP₂, namely, when tap speed is 11.3 m/min, temperature of cryogenic treatment is -120°C, and rounded cutting edge radius is 0.032mm, HSS tap life is 620(holes).

Abstract: Single abrasive-grain cutting is the key research point in grinding process. Because of the narrow space and quick velocity, modeling and simulation method is an approach way to study the single grain cutting. This paper studied the distribution of flow stress and plastic strain, the temperature field near cutting grain. Then experiment was conducted to measure the cutting forces in single grain cutting test. The validation shows good correctness and accuracy of FEA model. Then orthogonal simulation test was carried out to research the influence factors for the grinding forces and temperature distribution. It is found that creep feed grinding has a large grinding forces than high speed grinding in the grain scales. But the maximum temperature value is affected both by depth and speed distinctly.

Abstract: The transverse vibration should be controlled of the up-going strip emerging from the zinc pot of hot-dip galvanizing line because it directly affects the quality of zinc coating. In this paper, the up-going strip is separated from the whole hybrid system at the point where the system is away from the modal transition point in the parameter space. The dynamic equations and boundary conditions of the up-going strip are established. The Galerkin method is used to discretize the partial differential equations. One-third sub-harmonic resonance of the steel strip is explored by multiple scale method for different incentive amplitudes under different strip speed. The result shows that: there is a critical strip speed, above which one-third sub-harmonic resonance occurs. In the actual production process, the strip speed should be adjusted properly in order to avoid one-third sub-harmonic resonance.

Abstract: Compared with minimal quantity lubrication (MQL), electrostatic atomization can control the movement of mist droplets by changing the electrostatic field, thus reducing the drift of mist droplets in air. This paper first proposes the concept of electrostatic atomization cutting, and then develops a 3D FE model of electrostatic field for electrostatic atomization cutting using a commercial software Ansoft Maxwell. By simulation, the influence of nozzle angle, structure, and electrode gap and voltage on electric field intensity is investigated. Based on simulation results, the optimal nozzle angle and structure are obtained for electrostatic atomization cutting. The findings contribute to further development of this technique.

Abstract: To analyze liquid metal flow in mold under multidimensional vibration condition, discrete element method (DEM) is taken to approximately stimulate liquid metal flow and to simulate numerically liquid metal flow filling process in casting technique under multidimensional vibration. The orthogonal experiment design is taken to study vibration dimension, frequency as well as amplitude influence on liquid metal filling capacity; Through EDEM platform, numerical simulation research in each test scheme can be carried out to get influence of filling time upon sensitivity degree of each parameter index so as to select the optimal test scheme. Casting experiment results in the self-made solidification test-bed under multidimensional vibration match the numerical simulation, showing that multidimensional vibration could significantly improve filling capacity of castings.

Abstract: Based on the mechanism of single-excitation elliptical vibration by means of opening chutes on the horn, a novel two-dimensional ultrasonic cutting system was developed. Vibration characteristics of the two-dimensional ultrasound cutting system were researched and the longitudinal and bending amplitude of the system with different number of chutes were obtained. By using developed two-dimensional ultrasonic vibration cutting systems, series of cutting experiments were carried out and cutting force characteristics were researched compared with that in traditional cutting.

Abstract: High hardness surface coating sphere components are widely used in metal sealing ball valves. The spherical surface grinding texture influences the valve’s tribological performances such as friction, lubrication and wear of interacting surfaces. It can be used to develop the index of grinding parameter optimization. In this paper, based on the discussion of sphere generating grinding methods, the surface grinding texture is quantitatively analyzed. The space trajectory of abrasive particles during sphere grinding is studied. The trajectory mathematical models are built based on two kinds of sphere grinding manners and are verified by comparing the theoretical results against experimental measurements. The influence of grinding parameters on the texture is analyzed. Texture density are defined to quantitatively describe the surface texture. The relationship between grinding texture and ball valve performance is finally discussed. The conclusions can help to optimize the spherical surface grinding process.

Abstract: This paper made the digital model reconstruction of the RB211 high pressure turban blade. First, collected rough points cloud data by using visual measuring equipment. Then, finished pre-processing the point cloud data, took the rational simplification. Finally, a new algorithm was used to reconstructing the 3D digital model. The results proved that this method improved smoothness of the model, and reduced time and cost of modeling and machining.

Abstract: Stator current signal of driving motor can be easily measured. Using it in the gearbox fault diagnosis system is inexpensive and suitable for remote monitoring. According to the application of the Motor Current Signal Analysis in machinery fault detection, we present a new gearbox fault diagnosis system. In modern signal processing technology, Stochastic Resonance theory is widely used to improve SNR (signal to noise ratio). Dynamic time warping algorithm is a simple and efficient way of the pattern identified. Combine the Stochastic Resonance theory and dynamic time warping algorithm as the basic theory of fault diagnosis. To realize the development of fault diagnosis software, we use the mixed-programming of MATLAB algorithms library and VC++.

Abstract: Mechanical vibration analysis is an important index to measure the running state of the electromechanical equipment. The vibration signals contain the information about the equipment running state. This paper studies and designs the vibration monitoring system based on fiber Bragg grating (FBG). Through the finite element analysis simulation, optimizes the sensor's structure, and uses the labview software to compile the corresponding vibration monitoring analysis software. Finally verifies the detection effect of the monitoring system, through the pulse signal and continuous signal dynamic experimental analysis. The result of the experimental analysis shows: this vibration monitoring system can monitor the vibration information and analyze vibration state effectively. It has the advantages of reducing the temperature interference and lateral disturbance, and detects the vibration of three direction at the same time. So it is feasible to monitor the electromechanical equipment.