Applied Mechanics and Materials Vols. 37-38

Abstract: In injection molding processes, while the plastic is injected into the mold cavity, the displaced air leaves the mold through openings which are referred to as the venting slots. With the continuous improvements of manufacturing precision and injecting speed, the design of venting slot is becoming an important problem which influences the quality of products greatly. In this paper, five types of possible location to generate “gas-trap” were summarized based on the research and analysis of mold manufacturing and injection molding. The dimensions of venting slot, eight kinds of venting mode and their corresponding structures were presented. The principle for the design of venting system was proposed.

Abstract: According to the characteristic of machine tools such as complex driving chain and enclosed housing, this paper selects current signal which is easy to sample as the analytical signal. As the machines tools use different driving chain in different work state, this will affect motor current of machine tools; that is, the characteristics under different working conditions will be included in the current signal. This paper chose wavelet packet decomposition to analyze the current signal, then extracted wavelet packet coefficients of different frequency bands, by the change of wavelet packet coefficient to determine the machine's working condition. From the analysis of lathe current signal sampled in the experiment, it indicates the validity of wavelet packet coefficients as a feature quantity of the machine condition monitoring.

Abstract: The concept of contact is applied into the machining of the complex surface. If the contact line is along the straight line of cutter, the contact line should be along the asymptotic direction of the surface being machined. For the undeveloped ruled surface, the directions of the normal vectors are different, while the directions of the normal vectors on the straight line of cylinder are the same, so that there may be some over cutting on the surface. With the theory of this paper, the best cutter postural can be determined when the contact line is not along the straight line of the cutter. And further more, with the concept of third order contact, both the best cutter postural and contact direction can be determined at same time. This paper showed how to use this method for the machining of impeller leaf.

Abstract: One new sliding-block balancing mechanism is proposed for the single-cylinder diesel engine. In the new mechanism, the sliding block is installed against the engine piston. The reciprocation trajectory of sliding block is collinear with the piston trajectory, while sliding block and piston move in the opposite direction, just like two opposite crank connecting rods. The new mechanism includes the crankshaft, connecting rod ring, the slider and the guide components. Through the bearing, connecting rod is installed in the eccentric journal of the crankshaft. The circular connecting rod is in the accurate guiding surface of the slider; and the guide pins are in the guide groove. Guide rod connects with supporting shaft through the guide hole of the slide. The optimized parameters for the sliding block show that the ratio of eccentric distance of the eccentric journal to the length of the connecting rod is equal to the ratio of crank radius to connecting rod length. The appropriate results can balance both the centrifugal inertia force and the reciprocating inertia force generated by piston group. Even the complete balance of the first and second-order reciprocating inertia forces can be obtained, which can reduce the vibration and noise of diesel engine.

Abstract: Based on Extreme Value Theory (EVT), the Generalized Pareto Distributions (GPDs) of meteorological variables wind speed and freezing precipitation is simulated. Considering the dependence of them, a joint probability distribution is calculated by the Copula function. Further more, the probability distributions of ice loads and wind loads on transmission lines are analyzed, and the failure probability of broken lines and collapsed towers under ice storms is calculated. The accuracy and validity of this analytical method is demonstrated with comparison between numerical results and the historical datas of Chen Zhou power transmission systems.

Abstract: This article focuses on the separation of ferrous impurities from emulsion with micro-hydrocyclone. The relationship of flow rate, pressure and separation efficiency is studied to determine the optimal operation condition. Results show the separation efficiency and the pressure difference increase with the inlet flow rate of the micro-hydrocyclone. When the inlet pressure is 0.4MPa, pressure difference △Pio is 0.26Mpa and the average inlet particle size is 2.719μm, the separation efficiency of the solid particles is 76% and the removal rate of solid particles with the size above 5.5μm is 85.64%, which contributes to the improvement of the quality of cold rolled sheet.

Abstract: The lapping trace distribution on ball surface is one of the key factors during the lapping process, which can affect the sphericity of lapping. The Rotated Dual-Plates lapping mode (RDP lapping mode) can achieve better uniformity of lapping trace distribution on precision ball surface, which ensure the results of forming sphere by lapping. Combining with the basic principle of RDP lapping mode, as well as the analysis of the kinematics of the RDP lapping method, this paper puts forward a basic rule about the material removal at the contact point between the ball and the plate with the material removal rate equation of bearing steel, and the improvement of the sphericity which can be simulated, and is defined as the lapping uniformity according to basic rule equation. The influence caused by the lapping pressure and the speed of the plates are considered in the simulation, the surface of ball is triangle grid divided. The uniformity of lapping is evaluated at different speed ratio, and eventually a better curve of the speed ratio can be got, so the lapping uniformity during the RDP lapping mode can finally be accurately evaluated.

Abstract: The agility of manufacturing is the key to agile manufacturing (AM). An enterprise can achieve agile manufacturing by inter-firm cooperation or by improving the agility of firms itself internal process. The information about operating state of equipment plays an important role in agile manufacturing and it has a homologous relationship with load current, which has different features at different work loads. According to these, we can collect and statistic devices working information by detecting and analysing the current of the equipment. On this basis, we submit the implementation strategy for agile manufacturing based on equipment load current, achieve the goal of improving the overall agility of the manufacture enterprise by effective agility promotion of production operations planning and manufacturing process control. This method can promote the rationality of resource utilizations in process of manufacture, and improve the agility of the enterprise.

Abstract: This paper begins with physical characteristics and the basic working principle of the traditional switch-type Exhaust Gas Oxygen (EGO) sensor and Universal Exhaust Gas Oxygen (UEGO) senor, and then it analyses the Air-Fuel ratio (A/F) Self-learning Control strategy and designs A/F Self-learning Control algorithm of Electronic Control Turbocharged CNG lean-burn engine based on UEGO sensor. At the end, it uses the written control code into ECU of the test engine, and after bench calibration tests it shows that the designed algorithm can compensate wearing, tiring, aging and other state of the engine and improve A/F control accuracy.

Abstract: Nowadays, the variable speed function of metal belt CVT assemblied on vehicle is completely based on hydraulic system which is driven by the engine. The extra energy consumption is obvious and the reliability is low during the speed-change process of system because of low efficiency of hydraulic components such as pump and valve. In this paper, Electronic-Mechanical CVT (EMCVT) that is a new kind of metal belt CVT is proposed, which uses DC motor driving system to implement the variable speed function. The model of speed ratio control and the clamping force of cone-plates control is established and the PID algorithm of speed ratio control is presented while the transmission principle and mechanical structure of EMCVT is introduced through the study of artificial characteristic of DC motor and dynamics of the system.