共查询到19条相似文献,搜索用时 109 毫秒
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2003年5月的一天,一块亮如镜面的铝材凸球面车削样件被小心翼翼地从非球面曲面超精加工机床卸下,送入国家级光学计量检验中心检验。检验结果为:车削加工样件的面形精度PV=0.228μm,表面粗糙度Ra=0.0078μm,这意味着表面粗糙度仅有不到8nm。这是三○三所研制的非球面曲面超精密加工机床在用户西安应用光学研究所进行交付验收时的一个场景。非球面曲面超精密加工机床的成功研制,表明三○三所超精密加工技术国防科技重点实验室比较全面地攻克了非球面曲面光学零件的超精密加工与测量的关键技术,打破了国外的技术封锁,使我国的非球面曲面光学… 相似文献
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建立超精密切削表面粗糙度预测模型是分析各切削参数对表面粗糙度影响和提高切削效率的关键,针对最小二乘法和传统反向传播神经网络等参数辨识方法的不足,提出将遗传算法优化的反向传播神经网络应用于超精密切削表面粗糙度预测模型的参数辨识中,得出采用金刚石刀具超精密切削铝合金的表面粗糙度预测模型,并与传统的参数辨识方法比较。实验结果表明该方法能更有效的辨识表面粗糙度预测模型,可为超精密车削加工表面质量的控制提供帮助。 相似文献
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对自主研制的T形结构超精密磨床进行改装,在超精密磨床的转台上安装单点金刚石圆弧车刀,进行了超精密车削试验研究。对超精密磨床和车床的结构、精度、刚度进行了分析和比较,确定在超精密磨床的基础上可以进行超精密车床的改造;通过调整静压导轨和刀具静压回转台的供油压力实现超精密车削刀具与工件回转中心高度的精确调整,可有效地实现工件回转中心区域的加工;利用刀具回转台的精密摆动实现刀具切削过程中切削刃位置的微调,为超精密车削提供可能。采用上述方法进行铝合金和无氧铜工件端面不同速度和不同进给量下的超精密车削试验,获得了表面粗糙度为10.8nm的超精密平面。 相似文献
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SiC_p/Al复合材料的超精密车削试验 总被引:1,自引:2,他引:1
试验研究了碳化硅颗粒增强铝基复合材料(SiCp/Al)的超精密车削加工性能.使用扫描电镜(SEM)对已加工表面、切屑及其根部、刀具前/后刀面磨损带进行观察,使用表面粗糙度轮廓仪对各种切削条件下的加工表面粗糙度轮廓进行测试分析.结果表明,该材料的加工表面常残留微孔洞、微裂纹、坑洞、划痕、残留物突起及基体材料撕裂等微观缺陷,刀具几何参数、切削速度、进给量、增强颗粒尺寸和材料体积分数是影响表面粗糙度的主要因素.由于切削变形区微裂纹动态形成的作用,超精密切削该材料时一般形成锯齿型切屑.刀具-工件的相对振动、基体撕裂增强颗粒拔出、破碎、压入等是该材料超精密车削表面形成的主要机制.单晶金刚石(SCD)刀具主要发生微磨损、崩刃、剥落和磨粒磨损,聚晶金刚石(PCD)刀具主要发生磨粒磨损和粘结磨损.结论表明SiCp/Al的超精密切削加工性较差,但通过选择合适的工艺参数,体积分数为15%的SiCp/2024Al加工表面粗糙度Ra可达24.7 nm. 相似文献
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针对超精密车削表面,提出一种基于多波长散射光特性的表面粗糙度测量方法,以铝合金为例对该方法进行验证。首先建立超精密车削表面形貌—散射光模型并开展验证实验,定量实验结果证明建立的散射光模型平均误差仅为1%。基于散射光模型研究刀痕纹理方向、刀痕宽度(每转进给量)和刀痕高度(表面粗糙度峰谷值)对镜像光反射率的影响,研究结果证明表面粗糙度是影响镜像光反射率的关键因素。在此基础上进一步建立300~700 nm波长范围内镜像光反射率平均值和表面粗糙度之间的定量关系,基于超精密车削表面的测量结果对该定量关系进行验证。所提出新方法获得的粗糙度测量结果与原子力显微镜测量结果吻合,最大相对误差仅为7.5%。 相似文献
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Wang Hongxiang Li Dan Dong shen Precision Engineering Research Institute Harbin Institute of Technology Harbin China 《机械工程学报(英文版)》2002,15(2):153-156,176
A surface roughness model utilizing regression analysis method is developed for predicting roughness of ultra-precision machined surface with a single crystal diamond tool. The effects of the main variables, such as cutting speed, feed, and depth of cut on surface roughness are also analyzed in diamond turning aluminum alloy. In order to predict and control the surface roughness before ultraprecision machining, constrained variable metric method is used to select the optimum cutting conditions during process planning. A lot of experimental results show that the model can predict the surface roughness effectively under a certain cutting conditions . 相似文献
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Tao Chen Suyan Li Bangxin Han Guangjun Liu 《The International Journal of Advanced Manufacturing Technology》2014,72(9-12):1639-1645
This work investigates the cutting force and surface micro-topography in hard turning of GCr15 bearing steel. A series of experiments on hard turning of GCr15 steel with polycrystalline cubic boron nitride (PCBN) tools are performed on a CNC machining center. Experimental measurements of cutting force, 3D surface micro-topography, and surface roughness of the workpiece are performed. The 3D surface micro-topography of the workpiece is discussed, and the formation mechanism of the 3D surface is analyzed. The influence of cutting speed and feed rate on cutting force and surface roughness are discussed. The 2D and 3D surface roughness parameters are compared and discussed. It is found that feed rate has greater influence on cutting force and surface roughness than cutting speed and there exists the most appropriate cutting speed under which the minimum surface roughness can be generated while a relatively small cutting force can be found. Recommendations on selecting cutting parameters of hard turning of GCr15 steel are also proposed. 相似文献
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Aref Saliminia 《Machining Science and Technology》2013,17(5):779-793
AbstractSurface roughness is one of the most common criteria indicating the surface finish of the part, which depends on various factors including cutting parameters, geometry of the tool, and cutting fluid. One of the goals of using cutting fluids in machining processes is to achieve improved surface finish. In addition to high costs, commonly used cutting fluids cause dermal and respiratory problems to the operators as well as environmental pollution. The present article aims at investigating the effect of spray cryogenic cooling via liquid nitrogen on surface roughness and cutting ratio in turning process of AISI 304 stainless steel. Through conducting experimental tests, the effects of cutting speed, feed rate, and depth of cut on surface roughness and cutting ratio have been compared in dry and cryogenic turning. A total number of 72 tests have been carried out. Results show that cryogenic turning of AISI 304 stainless steel reduces surface roughness 1%–27% (13% on the average), compared to dry turning. The obtained results showed that the cutting ratio in cryogenic turning is averagely increased by 32% in comparison with dry turning, also that chip breakage is improved in cryogenic turning. 相似文献
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Surface roughness and cutting force prediction in MQL and wet turning process of AISI 1045 using design of experiments 总被引:1,自引:0,他引:1
This paper presents an investigation into the MQL (minimum quantity lubrication) and wet turning processes of AISI 1045 work
material with the objective of suggesting the experimental model in order to predict the cutting force and surface roughness,
to select the optimal cutting parameters, and to analyze the effects of cutting parameters on machinability. Fractional factorial
design and central composite design were used for the experiment plan. Cutting force and surface roughness according to cutting
parameters were measured through the external cylindrical turning based on the experiment plan. The measured data were analyzed
by regression analysis and verification experiments were conducted to confirm the results. From the experimental results and
regression analysis, this research project suggested the experimental equations, proposed the optimal cutting parameters,
and analyzed the effects of cutting parameters on surface roughness and cutting force in the MQL and wet turning processes. 相似文献