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排序方式: 共有6509条查询结果,搜索用时 15 毫秒
71.
通过对电机定、转子片级进冲模结构形式的分类、凸模、凹模常见的固定方式的介绍,阐述了电机定、转子片级进冲模模具在日常使用中的维护和保养要领。重点介绍了凸模、凹模的更换程序,卸料板的安装程序,以及模具在使用中常见故障原因的分析和排除方法。 相似文献
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介绍了在油缸低速工作流量小于凋速阀最小稳定流量时,通过增压缸与油缸的串联,实现工作油缸稳定低速运动的一种设计方法,并对油缸与增压缸串联后回路的动态特性进行了分析。通过应用于辗扩机液压低速运动回路中的实例表明,该方法可有效地改善机床的低速运行的稳定性和可靠性。 相似文献
75.
M. Yoshida H. Ishibashi K. Susa T. Ogura E. Akiba 《Journal of Alloys and Compounds》1995,230(2):100-108
The crystal structure, hydrogen absorbing properties and electrode performance of Laves phase alloy systems, Sc---Zr---Ni---Mn and Sc---Ni---V systems, were studied by optical and scanning electron microscopy, X-ray powder diffraction, pressure-composition isotherm and electrochemical measurements. C14 and C15 Laves phases and minor ScNi-related phase were found in the Sc---Zr---Ni---Mn alloy system. The ScNi-related phase was composed of Sc, Zr and Ni elements. Two kinds of minor phase, BCC and ScNi-related phases, were identified in addition to the C15 phase in the Sc---Zr---Ni---V alloy system. The BCC contained mainly the element V. The ScNi-related phase contributed to an increase in the hydrogen capacity, but those in the V alloy system did not. The multiphase anode with a large amount of the ScNi-related phase showed a low durability against the KOH electrolyte. The substitution of Zr by Sc led to an improvement in the initial activation of the anode, but there was not a clear correlation between the presence of the multiphase in the anode and the rate capability. 相似文献
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77.
In-process evaluation of grit protrusion feature for fine diamond grinding wheel by means of electro-contact discharge dressing 总被引:1,自引:0,他引:1
This paper introduces a new in-process evaluation method for grit protrusion feature on wheel surface by monitoring discharge current trace during electro-contact discharge (ECD) dressing of metal-bonded fine diamond grinding wheel. First an impulse discharge machining experiment was carried out to investigate the correlation between metal bond removal and discharge parameters, namely discharge current Ie and discharge pulse duration τe. Then ECD dressing experiment for #600 diamond grinding wheel was conduced to analyses the quantitative effect of the discharge parameters (Ie and τe), derived from discharge current trace between wheel and dresser (electrode), on grit protrusion feature of wheel surface. The result shows that the grit protrusion feature is sensitive to the discharge parameters (Ie and τe) with reference to mean diamond grit size dgm. Further, the discharge parameters (Ie and τe) in ECD dressing should conform to the discharge variables’ requirement of , by which the grit protrusion feature may be evaluated and the dressing process variables may be determined. Finally, the in-process evaluation method was successfully applied to ECD dressing of #1500 diamond grinding wheel for valid grinding of hard-brittle materials. 相似文献
78.
Fluorinated amorphous hydrogenated a-C:F:H carbon thin films were deposited using radio frequency plasma enhanced chemical vapor deposition(RF-PECVD) reactor with CF4 and CH4 as source gases and were annealed in a N2 atmosphere. The properties of these films were evaluated by FTIR spectrometry, UV-VIS spectrophotometry and single-wavelength spectroscopic ellipsometry. A correspondence relativity connection between the deposition rate and technology was found. The chemical bonding structures and the content of CHx and CFx in the films are transformed and the optical band gap decreases monotonically with increasing temperature after annealing.The dielectric constant is increased with decreasing content of F in the films and the optical band gap is decreased with decreasing the content of H in the film. 相似文献
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80.
Y.S Wong M Rahman H.S Lim H Han N Ravi 《Journal of Materials Processing Technology》2003,140(1-3):303-307
Similar to EDM, in micro-EDM, intense heat is generated between the workpiece and tool electrode by the discharge through a dielectric medium to result in the formation of a microcrater that is much smaller in size. In this study, a single-spark generator has been developed to study the erosion characteristics from the microcrater size. Using a simple heat transfer model, the efficiency at different discharge condition is also deduced. It is found that at lower-energy (<50 μJ) discharges, the energy required to remove the unit volume of material, defined as the specific energy, is found to be much less than that at higher-energy discharges. Additionally, the ratio of the standard deviation to the measured microcrater size is found to be lower at lower discharge energy, indicating greater consistency in shape and size when the discharge occurs at lower energy. The fundamental erosion mechanism of material is discussed by considering melting and evaporation phenomena using theoretical modeling. The average efficiency of erosion, when estimated to be due primarily to melting or evaporation alone, is found to be up to an order of magnitude higher at lower-energy discharges than that at higher-energy discharges. 相似文献