Applied Mechanics and Materials Vol. 703

Abstract: This paper presents process optimization for the five-axis milling based on the mechanics model explained in Part I. The process is optimized by varying the feed as the tool-workpiece engagements. The linear and angular feedrates are optimized by sequential quadratic programming. Sharp feedrate changes may result in undesired feed-marks on the finished surface. The adopted step is to update the the original CL file with optimized and filtered feedrate commands. The five-axis milling process is simulated in a virtual enviroment, and the resulting feedrate outputs are stored at each position along the tool path. The new feedrate profiles are shown to considerably reduce the machining time while avoiding process faults.

Abstract: Improved artificial bee colony algorithm is proposed to solve the problem that how to select proper cutting parameters in multi-processing of slender bar in this passage. Under these constraints of cutting stability, surface roughness, cutting quantity and etc , the algorithm combined with four type decreasing inertia weight is used to search maximize production rate which is regarded as the objective function .The result indicates that the improved algorithm is of high effectiveness, high global convergence reliability and high velocity. The two convex functions strategy can greatly enhance convergence speed of the algorithm under the good accuracy of convergence conditions. The experience has proved the improved algorithm for solving the slender shaft turning parameter optimization has a theoretical significance.

Abstract: The cutting location of cutting-edge curves is obtained by the mathematic models of indexable inserts, and based on the softwares of UG and NCSIMUL, The virtual machining platform is realized to simulate the whole processing of grinding. The Entity modelings of indexable inserts are obtained by Boolean operation in virtual environment, and the basis is presented for analyzing accuracy of the mathematic models and the virtual machining platform. Testing efficiency of NC code and reliability of high speed grinding are improved. This method provides precise 3D models which can be used in the followed works such as finite analysis, CNC machining and so on.

Abstract: Numerical control reform of ordinary lathe has the advantages of economy, practicality and stability. In order to ensure the accuracy of the feed system, vertical screw pair must be exchanged for a ball screw pair. The processing precision of the work piece can be guaranteed. Combined with the practice, this paper discusses the ball screw pair selecting in the reforming process of NC lathe. And the aspects of its size, precision, bearing capacity is checked.

Abstract: Improved step-feed de-nitrification progress combined with biological fluidized bed was introduced in this study. The progress had good performance and capacity of de-nitrification and organic matter. The experiment result showed that the de-nitrification efficiency of the improved biological fluidized bed with step-feed process was higher than the fluidized bed A/O process under the same water quality and the operating conditions. When the influent proportion of each segment was equal, the system showed good nitrogen removal efficiency with the change of influent C/N ratio, HRT and sludge return ratio. The removal rate of TN reached up to 88.2%. It showed that the simultaneous nitrification and de-nitrification phenomenon happened in the aerobic zone. The nitrogen removal mechanism was also studied.

Abstract: In order to solve the recognition problem caused by the distortion of two-dimensional bar code printed directly on the cylindrical units, a correction method has been put forward based on the combination of the information of space geometry calibrated in the camera and that of the image. Firstly, we should obtain the fixed parameters relating to the machine vision and then analyze how the two-dimensional bar code distorts on the cylindrical surface to find the correction method reversely. Since the cylindrical units vary from each other, it would be difficult to calibrate the radius of the units. Only by analyzing the perspective projection of the edge of the two-dimensional bar code on cylindrical surface and then founding the estimating function of radius can the parameters of radius be obtained from the image information. At last, the rationality of the algorithm is proved by experiments

Abstract: Springback is one of the main quality defects in the sheet forming. In this paper, numerical simulation is used to analyze the effects of blank holder force, friction coefficient, blank thickness, die corner radius and stroke on springback. The effect of blank holder force and blank thickness on springback is obvious. Springback decreases as the BHF and blank thickness increase. Increasing friction coefficient between tools and blank shows a good suppression effect on springback. Larger die corners increase the curvature of side wall and worsen the springback, but the springback of flange is reduced. The greater the stroke is, the larger the final springback will be.

Abstract: The effect of heat treatment on gradient wetting of (meth) acrylate polymer film surfaces was analyzed. Poly (methyl methacrylate – butyl acrylate) and poly (methyl methacrylate – butyl acrylate - 2-hydroxyethyl methacrylate) were prepared by the free radical solution polymerization and their coating film wettability was obtained by measuring water contact angles (CAs). The gradient wetting surface was fabricated by a simple controlled ester group hydrolysis process on (meth) acrylate polymer film. The gradient wetting properties were attributed to the gradient surface chemistry from the ester group to acid salt on copolymer film. The copolymer films of gradient wetting were heated at 100 °C. It is found that the gradient materials will exhibit the unique wetting with the heating time increasing and the heat-resistance property of gradient surface needs further research.

Abstract: It is feasible to polymerize SMPU from MDI, PBA, BDO and DMF. Each component has a good ductility, but there are insufficient in terms of strength, glass-point temperature, crack resistance and implosion tendencies. The formulation (PBA: BDO: MDI: DMF=1: 3: (3-4): (7-8)) is recommended. SMPU polymerized by this proportion has good comprehensive properties. The effect of the two-step prepolymerization method, especially the full polymerization method is satisfactory. The composite Materials obtained from powders and particles by hot press molding and that formed by cotton fabric have good ductility. Finally, some suggestions are proposed about implosion preventing, casting crack preventing and development technology.

Abstract: The current volume design method of SMA is the comparison of volume characteristic parameters (VCA in the mixes,VCA in the dry rodded condition) between aggregates and the mixture,but ignores the systematic error between them.It is the different molding method and different tamping container that cause systematic error.The study compares Marshell compaction method and the Gyration compaction,tamping density tesy of Gyration tube and Marshell tube,and analysis the results.Choosing the Gyration compaction and gytatory tube to measure VCA is more reasonable.