Key Engineering Materials Vols. 315-316

Abstract: Nickel deposits were electroformed by a novel technique, in which the mandrel rotated in hard particles (such as ceramic beads) filling between the electrodes. The microstructure and microhardness of the deposit were studied by means of SEM, XRD analysis in contrast with the traditional method. The effects of current densities on the surface morphology and microhardness of the deposit were also studied. The results showed that the polishing, impacting and disturbing of hard particles during electrodepositing could affect the microstructure and performance of the deposits. The grains were substantially refined, the preferred orientation of (200) face weakened and the microhardness significantly increased. Moreover, the presented technique could use higher current density and produce bright and smooth deposits.

Abstract: In accordance with the obvious characteristics of the pressed raised character image and the shortages of the template matching method.
a new method of using the general radial-basis function neural network (GRBFN) for testing the quality of the pressed character is presented. The structures and training methods of GRBFN are fully analyzed, as well as the functionality of hidden layer, excited focus and area. The results show the checker based on GRBFN has highly checking ratio for the label pressed raised characters. It is suited to the quality testing of raised characters.

Abstract: First, the problems in cutting database are analyzed and primary factors that should be considered in establishing high-speed cutting database are pointed out, including data presenting modes, data collecting and updating, the intelligence of the database, and the integration with CAD, CAPP and CAM. Secondly, high-speed cutting system is analyzed. On the basis of the categorization of the variables, the function model and the information model of cutting database are set up, which leads to the establishment of the architecture of high-speed cutting database. Finally, the combination mechanism of the rule-based reasoning and the case-based reasoning is analyzed and the process of the hybrid reasoning is given.

Abstract: Both diamond wheel and CBN wheel belong to super-abrasive wheels. Diamond wheels have superior grinding performance. The metal-bonded diamond wheel can grind hard brittle material component with a complicated shape precisely and efficiently. Because dielectric liquid is forbidden on numerical control optical profile grinder, the information on profile truing and dressing diamond wheel mounted on numerical control optical profile grinder is not readily available. In this paper, a novel truing and dressing method, namely dry electrical discharge (dry-ECD) assisted truing and dressing, is proposed. The experiments of dry-ECD assisted profile truing and dressing of diamond wheel are done by the authors. The experimental results show that both geometrical accuracy and surface topography of diamond wheel have attained technical requirement under appropriate truing and dressing conditions. There is not much difference in grinding abilities of new diamond wheel and dry-ECD assisted truing and dressing diamond wheel.

Abstract: The effect of sintering temperature on mechanical properties and microstructure of rare earth oxides toughened Ti(C,N) ceramic cutting tool materials was investigated. The results showed that the mechanical properties of Ti(C,N) based ceramics were greatly influenced by sintering temperature. As a result, both of the density and mechanical properties of the materials sintered at 1350
and 1400
are worse than those sintered at 1450
and 1500
. Low sintering temperature results in low density and degraded mechanical properties, but too high sintering temperature results in the precipitation of bond metal and thus reduces its fracture toughness. Intergranular fracture mode of the material is mainly observed.

Abstract: This paper deals with nanometer positioning in the presence of friction. The object researched is a ball-screw-driven and linear-ball-guide-supported table system. For such system, models that do not account for friction can only be applicable to describe the macrodynamic behavior which is significantly different from the microdynamic one. A PID controller is designed with high-loop gain to suppress the effect of friction. The controller parameters are calculated by pole placement according to macrodynamics, no identification of friction and friction model are necessary. Experiment and simulation results indicate that nanometer positioning can be realized in this system by the controller. In point-to-point (PTP) positioning for step heights from 0.1μm to 1mm, the positioning error is within ±5 nm and the response characteristics are satisfactory.

Abstract: In the course of the milling experiments with the difficult-to-machine material 3Cr-1Mo-1/4V steel, we have found the substance of the adhering disrepair. In addition, we forecast the predominant capability of the waved-edge milling insert with complex 3-D grooves by the synthetically blurry judgement. Eventually, we give the mathematical model between the milling temperature and the maximal adhering disrepair depth of the rake face, and analyze the rule that the milling temperature affects the adhering disrepair. What’s more, we testify the predominant capability of the waved-edge milling insert.

Abstract: Diamond film made by adopting the Chemical Vapor Deposition (CVD) technology is a promising superhard material. The mechanical and physical properties of CVD diamond is between natural diamond and hot press polycrystalline diamond. The cutting tools made by CVD diamond can machine many kinds of material, such as nonferrous metals, non metallic materials and composites. CVD diamond is classified as thin and thick films, and the thick film cutting tools are widely used. However, the superhard cutting tools cannot be applied to the cutting of iron family metal and molybdenum (Mo). In this paper, data and curves on machining test of CVD diamond cutting tools are listed and then analyzed.

Abstract: In order to machine high accuracy Potassium Dihydrogen Phosphate (KDP) crystal part, the indentation experiments are carried out with various loads and various orientation angles. The experimental results show that the critical condition of brittle-ductile transition of KDP has strong anisotropy. Therefore, the influence factors on the surface quality of crystal KDP was discussed, it is shown that influences of the tool's geometry parameter, feed rate and Nominal depth of cut etc on the surface quality of KDP are main. Afterwards the cutting experimental study on crystal KDP material is carried out. The experimental results show that the super-smooth surface quality only can be obtained while KDP is ultra-precision machined in ductile mode.

Abstract: Electrochemical machining (ECM) has been rarely applied in micromachining because the electric field is not localized. In order to explore the feasibility of applying ECM to micromachining at micro to meso-scale, an experimental setup with precision control over electrochemical micromachining (EMM) was developed, which is in fact a multifunctional machine tool. The micro tool electrodes for EMM can also be fabricated by micro electrical discharge machining (EDM) on the same machine tool. A high-frequency short-pulse micro-energy MOSFET power supply was designed. Lower machining voltage and lower concentration of passivity electrolyte are utilized together to localize dissolution area in EMM. A micro hole 45 ,m in diameter was drilled by EMM on stainless steel foil with 100 μm thickness. A new approach of fabricating microstructures by means of EMM milling using a simple micro tool electrode is proposed, and a shaped hole and a micro cantilever beam with high precision were acquired by EMM milling. The satisfactory process results indicate the potential capability of EMM for higher machining accuracy and smaller machining size.