Advanced Materials Research Vols. 753-755

Abstract: The cutting force and the distribution of temperature’s change and impaction of some carbide cutter are analyzed by FEM. By comparing, the tool wear is gotten. This result may offer some theory to get the cutter characteristics and give some reference to the designing of the cutting edge.

Abstract: Nano-ceramic materials had high hardness and wear resistance. Combined with current technology and cost saving, nanostructured coatings technology were carried out, using HVOF ( high velocity oxygen fuel) or plasma spraying technique can obtain high quality ceramic coating on metal substrate. Ceramic coatings produced cracks in the grinding due to grinding surface residual stress. the coatings grinding surface residual stress of engineering ceramics have been researched, grinding surface residual stress in the nanostructured ceramic coatings are being researched. the researches in this field include grinding process modeling, abrasives and grinding parameters, grinding process monitoring and control and realization of the software, the grinding mechanism and grinding damage on the surface, grinding force prediction, on-line detection, grinding on nanocoating material is a multivariable complex process.

Abstract: The grind-hardening method suitable for external grinding is proposed in this paper and the experiments are carried out on MI432B grinding machine.The hardened layer of the workpiece with cut depth 0.3mm and speed 0.2 m/min is analyzed.The result indicates the metallurgical structure of the hardened layer is martensite and the top hardness value is 754 HV(about 620 HRC).At the same time,the grinding force,one of the most important factors of grind-hardening process is modeled, and the measurement method is provided with elastic core clampers.The measurement result shows that the values of both the tangential force and the normal force increase when the cut depth increases,and the top value is 146 N and 656 N with the cut depth value of 0.4 mm respectively.

Abstract: The impact of cutter against the materials can be regarded as the rigid ball with certain energy oblique impact against the semi infinite space in the ultrasonic vibration cutting process. The cutter and materials three-dimensional surface stress state was theoretically deduced from building the dynamic shock model in Hertz contact state. Ultrasonic vibration cutting in the tiny cutting depth can be regarded as the contact extrusion process of blunt pressure head oblique impact on materials, the material indentation and crack development trend was given based on the surface stress analysis and test results of rigid ball oblique impact on the glass. The indentation and crack development of spherical pressure head oblique impact on the brittle materials was analyzed, material failure in the back edge with deeper crack is controlled by tensile stress, the tensile stress values depend on the friction coefficient and the normal pressure, material failure crack caused by shear stress on both sides exist on the material surface. Ultrasonic vibration can reduce normal pressure and crack to come into being. Cutting fluid lubricating can reduce the friction coefficient to control with only shallow crack produced in the cutting process.

Abstract: CBN cutting tool is used to cut hardened GCr15 bearing steel. Based on the surface roughness under different cutting parameters, people built the prediction model of surface roughness by Linear Regression algorithm, and carried on the significance test of it, the results show that the surface roughness forecast model set up by linear regression algorithm has a certain reliability and its linear regression equation is significant; among the cutting parameters, cutting speed and feed rate make great impact to the surface roughness and back engagement of the cutting edge has little impact to the surface roughness of test specimen.

Abstract: Under the special circumstances, we cannot use the lubricating medium and want to overcome the lake of friction properties of the single material in the cutting process, we will be done mainly through two ways: prepared self-lubricating tool and preparation of coating tools, in order to work reliable under the extreme conditions.

Abstract: Engineering ceramic are special hard and brittle materials, their surface properties are very sensitive to the state of the surface stress, the compressive residual stress can be improved part strength and surface properties in a certain extent, especially can increase breaking strength, tensile residual stress in the opposite role. The choice of grinding parameters and grinding temperature have great influence on the residual stress. improving grinding conditions can improve the surface properties, within a certain range, increasing grinding depth and reducing grinding temperature are advantageous to produce the beneficial compressive residual stresses on the surface properties.

Abstract: As a green machining method, the minimum quantity lubrication (MQL) technology has been investigative by many researchers. Currently, the main directions of MQL research are the type of oil, droplet size and distribution, the form of chips and surface roughness, cutting temperature and tool wear. Further, in order to achieve a good surface finish on a machined part with an optimum amount of MQL or a new tool material is to be replaced with lower coefficient of friction and high heat resistance.

Abstract: Ultra-precision machining is in the forefront of advanced manufacturing technology and also will become the basis of future manufacturing technology. Ultra-precision machining already has turned into the enabling technology to success in the international competition. Some new progresses in traditional ultra-precision machining processes including processing and measuring techniques, machining equipment, and analysis methods are introduced in this paper. Components with high form accuracy and good surface roughness are widely applied to precision apparatuses. Structured surfaces can be acquired by selecting reasonable machining parameters before mechanical process. The continuous growing markets will fuel many industrial sectors by ultra precision machining. We should pay great attention to the further developments of this technology.

Abstract: Chemical polishing of Q235 steel workpiece using H2O2as oxidant in chemical polishing solution was studied. The effects of quantity of components such as brightening agent, corrosion inhibitor, and stabilizer as well as the polishing time and polishing temperature were investigated. The optimized composition of the chemical polishing solution and process condition were obtained as follows: 14mL of H2O2(30%), 2mL of H2SO4 (98%), 10g of citric acid, 3.5g of urea, 2g of PEG 6000, and water added to 1000mL , polishing time at room temperature was 90~130s.