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161.
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163.
Biing Hwa Yan Hsien Chung Tsai Fuang Yuan Huang Long Chorng Lee 《International Journal of Machine Tools and Manufacture》2005,45(3):251-259
Alumina particle reinforced 6061 aluminum matrix composites (Al2O3p/6061Al) have excellent physical and chemical properties than those of a traditional metal; however, their poor machinability lead to worse surface quality and serious cutting tool wear. In this study, wire electrical discharge machining (WEDM) is adopted in machining Al2O3p/6061Al composite. In the experiments, machining parameters of pulse-on time were changed to explore their effects on machining performance, including the cutting speed, the width of slit and surface roughness. Moreover, the wire electrode is easily broken during the machining Al2O3p/6061Al composite, so this work comprehensively investigates into the locations of the broken wire and the reason of wire breaking.The experimental results indicate that the cutting speed (material removal rate), the surface roughness and the width of the slit of cutting test material significantly depend on volume fraction of reinforcement (Al2O3 particles). Furthermore, bands on the machined surface for cutting 20 vol.% Al2O3p/6061Al composite are easily formed, basically due to some embedded reinforcing Al2O3 particles on the surface of 6061 aluminum matrix, interrupt the machining process. Test results reveal that in machining Al2O3p/6061Al composites a very low wire tension, a high flushing rate and a high wire speed are required to prevent wire breakage; an appropriate servo voltage, a short pulse-on time, and a short pulse-off time, which are normally associated with a high cutting speed, have little effect on the surface roughness. 相似文献
164.
讨论了对NC程序进行检错的意义,提出了数控车床碰撞检测系统的总体结构,包括机床、夹具等加工环境。以及与CAD软件的集成模块。介绍了NC程序的特点,并在VC6.0环境下开发了NC程序检错与纠错模块.通过设计数据结构解决了碰撞检查过程中工件不断变化的难题,为进一步具体研究奠定了基础。 相似文献
165.
薄壁管小弯曲半径数控绕弯成形芯模效用的实验研究 总被引:2,自引:1,他引:2
薄壁管数控弯曲中带芯头的柔性芯模是提高薄壁管件成形极限和成形精度的关键因素。文章建立了绕弯过程芯模(包括芯棒和芯头)的理论解析模型,包括了芯模直径d、芯棒伸出量e、芯头个数n、芯头厚度k、芯棒/芯头孔心间距p及芯棒圆角半径r等参数的选取公式的推导,获得了不同弯曲规格下的芯模参数取值范围,验证了解析模型的合理性;实验研究了芯模参数对管材失稳起皱、壁厚减薄和截面畸变的影响规律。通过分段抽芯的工艺方法,完成了38mm×1mm×38mm(1D)高难度不锈钢管件的弯曲。 相似文献
166.
167.
The effect of grinding on the surface layer properties of ceria and yttria partially stabilized zirconia plasma-sprayed coatings
(CePSZ, YPSZ, respectively) has been studied by X-ray diffraction methods. For this purpose, the modified model of line broadening
analysis has been derived. The model considers elastic anisotropic properties along with more random paracrystal imperfections,
both affecting X-ray line broadening. Grinding-induced microstructural changes were also studied using an estimation from
the quantitative Orientation Distribution Function (ODF) texture. It was concluded, based on this work, that CePSZ ceramic
is less mechanically stable compared to YPSZ. Consequently, more beneficial mechanical properties of a ground surface layer
can be expected for CePSZ plasma-sprayed coatings. 相似文献
168.
The originality of this work consists in taking photographs of chips during the cutting process for a large range of speeds. Contrary to methods usually used such as the quick stop in which root chips are analyzed after an abrupt interruption of the cutting, the proposed process photographs the chip geometry during its elaboration. An original device reproducing perfectly orthogonal cutting conditions is used because it allows a good accessibility to the zone of machining and reduces considerably the vibrations found in conventional machining tests. A large range of cutting velocities is investigated (from 17 to 60 m/s) for a middle hard steel (French Standards XC18). The experimental measures of the root chip geometry, more specifically the tool-chip contact length and the shear angle, are obtained from an analysis of the pictures obtained with a numerical high-speed camera. These geometrical characteristics of chips are studied for various cutting speeds, at the three rake angles −5, 0, +5° and for different depths of cut reaching 0.65 mm. 相似文献
170.
Finite element prediction of material removal rate due to electro-chemical spark machining 总被引:1,自引:1,他引:1
K.L. Bhondwe Vinod Yadava G. Kathiresan 《International Journal of Machine Tools and Manufacture》2006,46(14):1699-1706
Electro-chemical spark machining (ECSM) is an innovative hybrid machining process, which combines the features of the electro-chemical machining (ECM) and electrodischarge machining (EDM). Unlike ECM and EDM, ECSM is capable of machining electrically non-conducting materials. This paper attempts to develop a thermal model for the calculation of material removal rate (MRR) during ECSM. First, temperature distribution within zone of influence of single spark is obtained with the application of finite element method (FEM). The nodal temperatures are further post processed for estimating MRR. The developed FEM based thermal model is found to be in the range of accuracy with the experimental results. Further the parametric studies are carried out for different parameters like electrolyte concentration, duty factor and energy partition. The increase in MRR is found to increase with increase in electrolyte concentration due to ECSM of soda lime glass workpiece material. Also, the change in the value of MRR for soda lime glass with concentration is found to be more than that of alumina. MRR is found to increase with increase in duty factor and energy partition for both soda lime glass and alumina workpiece material. 相似文献