Key Engineering Materials Vols. 392-394

Abstract: The mechanical equipments driven by induction motor are widely used in manufacturing. Aiming at this type of equipment, some holes are advisedly drilled on the bars to simulate the broken bar faults of the motor, and with on-off loads changes of output circuit of the load generator, forced torsional vibration of rotor was generated. Using the above simulation test ways, the typical faults of motor and its driven equipment are tested and analyzed. In addition, an signal analysis method using Hilbert conversion envelope spectrum and real modulation zoom envelope spectrum is proposed, this method can effectively extract the faults information of stator current, reject the useless power frequency. The experimental results indicate that: this method can identify not only the faults of the motor itself, but also municipal fault types of the motor’s driven equipment. Especially, through the contrastive experiments on the unbalance and the torsional vibration of the rotor, the conclusion is made that the method is more sensitive to torsional vibration detection. Also, it develops a new direction for the application and the research of sensorless detection and diagnosis method.

Abstract: Researches the leak malfunction of hydraulic cylinder, which is the center typical part of hydraulic pressure system. Use wavelet transform in detect the signal oddity aspect; the wavelet transform can examine the mutation points such as saltation signal, pulse signal and the signal biggest value etc. Tries to resolve leakiness breakdown the problem of the diagnosis in the new thinking. Examining accurately a time difference of pressure ascension points can judge if there is leak or not and severe degree of leak.It makes use of wavelet excellent zoom ability in space time and the graphical development environment of AMEsim , constructs the system mold, imitates to really analyze with dynamic state function, according to imitate a true result , the accuracy and the possibility of wavelet analysis method in diagnosing the leak malfunction of hydraulic cylinder can be got.

Abstract: Coating samples prepared by laser cladding were subjected to repeated impact fatigue experiment. It is observed through phenomenological analysis that most coating cracks are original from the surface. And then, the cracks extend by the combined action of coating inner stress and repeated impact compression stress. The formation of crack is close related to performance of coating material. It can be divided to traversed crack and reticular crack from surface side; it also can be divided to vertical extend crack and reticular extend crack from the cross section side. Rigid and brickle coating has a shorter repeated impact life because a kind of linear crack is formed easily in it. On the other hand, tougher coating has a long life. Mechanics of nucleation and expansion of crack was explained by using stress concentration theory and vacancy concentration theory. The anti-repeated impact fatigue performance of laser cladding part could be improved by increasing toughness and reducing hardness of the coating material. Furthermore, suitable dispersion strengthening and fine-crystal strengthening can obtain the same purpose.

Abstract: In order to predict the dynamic characteristics, the piezoelectric valve-less diffuser micropump is equivalent to the hydraulic model which consists of several hydraulic components. Using finite element analysis (FEA) method, the static analysis and the natural frequency calculation of the diaphragm are carried out. The mathematical model and the simulation method using AMESim are developed. Simulation results show the pressure and flow rate characteristics of the micropump, as well as the diaphragm stiffness influence. The agreement between the simulation results and those published previously indicates that the method combining FEA with the hydraulic analogue model provides a relatively simple and effective tool to study the dynamic characteristics of micropumps.

Abstract: In this paper, a system was introduced, which bases on Flame Cutter NC System and software platform of LabVIEW which the USA NI company developed. Composing of NC machine, partition of modules and assignments, functions confirming, data processing of machining and control, structure of software by the numbers and realization method of two CPUs. The system makes use of multitasking of LabVIEW to make the programmer realize easily the task, which is difficulty to acquire in in tradition programme. It is a kind of comparatively convenient and swift thinking to realize system interface and multitasking by the platform of LabVIEW.

Abstract: The Ni60A powder was clad on the copper by the laser through coaxial power feeding. The hardness and erosion resistance of the substrate and the cladding layer were measured and made contrasts. The morphology and the microstructures of the cladding layer were analyzed by scanning electronic microscopy as well as the microstructure of bonding interface. The contents of major elements in the bonding interface were studied by energy dispersive spectrometer. Moreover, large amount of (Cu and Ni) solid solution formed a metallurgic and tight bonding with the good dilution between the substrate and cladding layer.

Abstract: The waved-edge milling insert is a kind of insert with 3D complex groove; its cut-in style and cut-in disrepair are different from the flat-groove insert. For researching the relationship between the cut-in style and the cut-in disrepair of the waved-edge milling insert, the cut-in simulation system of the waved-edge milling insert is developed, on the software of UG/Open API combined with VC++. By given different cut-in style parameters, the virtual cut-in process is founded and the proof is supplied for judging cut-in style and studying cut-in disrepair.

Abstract: This paper presents the measurement of hanging weight method and two-point measureing method to the elastic component spring-tubes stiffness’ measurement, and analyzes the principle of the two measuring methods mentioned above. It simplifies the transforming zone to the structure of cantilever beam. It deduces the stiffness relation, which is from the two measuring methods. At the same time it modifies the transforming formula through experiment.

Abstract: The profile and temperature distribution of laser molten pool are mainly factors which have directly effect on quality of laser processing (laser melting and laser cladding). It is very necessary to study measurement method of melting process in laser molten poo1 on-line, for improving processing design and inspecting laser processing quality. A system of dynamic process measurement for laser molten pool was developed. The melting process of laser scanning molten pool formed by high power CO2 Laser was measured. Its temperature distribution was analyzed by special analysis software. It was shown that a section of integrated molten pool would come into being in the middle of the laser scanning line spot after a period of scanning time, and then the molten pool got increased in length with the time, and a little increased in width at the same time, the result was consistent with that of computer numerical simulation. Compared with laser focusing spot, laser scanning spot was more uniform in temperature distribution, that could be propitious to improve the quality of laser processing.

Abstract: The two-dimensional ultrasonic polishing device of big nano-ceramic plate was designed and its maximum value of vibration amplitude reached 18.34um.Using it to polish the nano-zirconia toughened alumina ceramic(ZTA) plates 500mm×400mm×16mm, the polishing efficiency improves and the polishing surface roughness achieves below 0.07um, flatness below 10um.