Applied Mechanics and Materials Vols. 395-396

Abstract: In this paper, on the basis of a large number of literature at home and abroad are summarized, we used the complete with independent intellectual property rights ultrasound wire-cutting processing machine tool to carry out machining experiment , and the ultrasonic wire cutting mechanism and process was carried out in-depth study. The results showed: compared with ordinary sawing, the cutting efficiency of applying ultrasonic action was high, its cutting force and surface roughness was small, at the same time ,used the software of ABAQUS finite element simulation analysis, and further studied on the law of electroplated diamond wire saw ultrasonic vibration cutting of composite processing technology process.

Abstract: The estimation and characterization of laser cutting heavy plate surface topography is very significant to the study on the formation mechanism of laser cutting surface and the relationship between machined surface formation and the processing parameters. The article characterizes the surface topography of the laser cutting heavy plate based on the fractal geometry theory, use box-counting method to calculate the fractal dimension of the laser cutting heavy plate surface. The results show the laser cutting heavy plate surface of low carbon steel has a obvious fractal feature, the fractal dimension of laser cutting surface range from 1.283 to 1.395 in a certain scale, the laser cutting surface topography is relatively complex, the relation between Fractal dimension D and surface roughness Ra are not linear correspondence, and then the surface topography of laser cutting heavy plate can be comprehensively estimated in accordance with D and Ra.

Abstract: The effect of the lateral vibration of the electrode wire on machining gap of CNC was analyzed. Then the vibration mathematical model of the wire electrode was established, and the influence of various parameters on the vibration and machining gap was revealed. Taking 1 mm wire as example, the influence low of the parameters on vibration of wire electrode was obtained. It shows that the vibration model is correct, to provide a reference for optimizing the machining gap of CNC.

Abstract: Laminated removal micro ED-Milling is a non-contact special processing technology, through electrode discharge removal in materials. Therefore, shape, size and overlapping degree of the discharge crater determine the surface roughness and surface morphology. Using the principle of electrode wears, through the experiment of Micro-EDM milling shallow groove under short single pulse, getting morphology of a single pulse discharge machining surface. And from the crater of morphological features analyses the different cause of formation, and contrasts in different electric parameters, the different of the electrode surface. For further analysis of the surface physical and mechanical performance changes to lay the foundation, and provides a way for the electrode material removal mechanism research and the calculation of the Single pulse discharge energy.

Abstract: Electrochemical machining (ECM) is an anodic dissolution process of metal as anode ion by ion, and micro-ECM is a promising micromachining method at micro to meso-scale. Thus, a micro-ECM setup was developed to fabricate micro parts and explore the feasibility of micro-ECM at micro to meso-scale, including the design of high-frequency micro-energy pulse power supply. By using the detection unit of machining state and optical encoder, a closed loop control system for micro-ECM was developed. Under low concentration of passivating electrolyte, low machining voltage, micro rotating electrode and high-frequency short-pulse current, the machining gap can be reduced to about 10μm. The influence factors of the additives and the rotation of micro electrode on micro ECM were analysed by experiments. A micro-hole about 30μm in diameter was drilled by the rotating micro electrode.

Abstract: The accelerated gas ions collide with the surface material, the atom or molecule on material surface is removed by momentum transferring. Depositing a layer low viscosity of the thin film materials on the original surface of the optical, such materials will form a layer thin film on the surface of optical element that is lower than the original. Remove the high-spatial frequencies and obtain super precision optical surface.

Abstract: The experiments of laser cladding on the surface of H13 steel were made. Molybdenum (Mo) wire and high-chromium (Cr) cast iron powder were used as cladding material. The microstructure and hardness of laser cladding layer were studied. The experiments showed that Mo wire and high-Cr cast iron cladding layer had better properties such as minute crystals, high density, no crack, no gas cavity and good metallurgical bonding with base metal. There was a slight melting on the surface of Mo wire which would greatly increase the binding force between Mo wire and high-Cr cast iron. Mo wire could make grain refine and limit the growing of carbide. The average hardness of junction zone of Mo wire and high-Cr cast iron was 750HV0.2 which was higher than that of cladding zone composed of high-Cr cast iron (650HV0.2).

Abstract: The relationship between welding quality and the shape of weld joint of pipeline steel and the factors which can make large influence over the shape of weld joint is analyzed in this paper. The pictures of weld joint in all kinds of welding conditions are taken into computer by some special ways in order to the pictures can be used to producing mathematic curves of weld joint shape. Welding quality and the shape of weld joint of pipeline steel can be forecasted and controlled by finding the best mathematic curve among all the curves which are fitted from the pictures of the weld joint of pipeline steel in all kinds of welding conditions by the computer software.

Abstract: With the self-developed physical simulation equipment of linear friction welding, the plastic flow heat transfer simulation experiment of low melting point Lead metal was implemented. A physical model of plastic flow heat transfer of linear friction welding low melting point metal was established based on the process of the Lead metal plastic flow recorded by high speed digital camera and the Lead metal temperature variation recorded by infrared thermal imager. Introducing the plastic flow element into one-dimensional unsteady heat transfer differential equation, heat transfer mathematical model of plastic zone, perpendicular to the direction of vibration, was proposed. Using finite difference method to solve this mathematical model, calculated value of this model and measured temperature was compared. The results show that the two values correspond basically, which indicates that the proposed model could be used to characterize the process of heat transfer of plastic zone during linear friction welding low melting point metal.

Abstract: A novel integrated heating and riveting control system for TB2 titanium alloy rivet based on the precise heating temperature and the heating time control is designed in this paper. The novel heating and riveting control system is implemented by using a linear current sensor to measure primary side current of output transformer of the control system so as to determine heating temperature, and using a microcontroller to precisely control heating time. Comparing to the difficult heating temperature control of the traditional rivet heating system of which heating time is controlled by time relay, our novel control system has implemented precise heating temperature control by precise heating time control and heating current control. The experimental results show the heating time error of rivet heater of this research is less than 0.1 second, and the novel control system is more reliable, convenient and accuracy than that traditional one controlled by time relay. The actual production results show required riveting temperature can be attained accurately under the condition of working voltage even with ±10% fluctuation, and the novel control system brings to increase the rate of finished products of riveted TB2 titanium alloy rivet about 15%.