共查询到20条相似文献,搜索用时 15 毫秒
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宋树藩 《世界制造技术与装备市场》2003,(4):45-45
随着把质量要求和费用提给航天工业分包商,后者对更高生产率,更低费用机床的需求也增加了。这类承包商之一,L.H.Thomson公司在一台新的Fadal VMC4020机床上找到了解决方案,此机床出自Fadel Engineering公司,装备了一个15000r/min的主轴。 相似文献
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Yong Zhang Yu Huang 《The International Journal of Advanced Manufacturing Technology》2018,96(9-12):3161-3174
The backplane processing is an important part of the manufacture of electronic communication equipment; the current processing of backplane surface, especially the rough machining, is still using milling; and the production efficiency is quite low. This paper presents a new method to turn with a cylinder for the rough machining of multi backplane surfaces, which is based on a conventional horizontal lathe and uses the improved method of noncircular machining. The performance requirements of fast tool servo (FTS) device and control model for the machining of noncircular surface are analyzed firstly; the position following control strategy is used instead of traditional position interpolation, according to the multi backplane surfaces machining technology and control strategy; and a novel algorithm, which is combined UG (Unigraphics NX) software surface fitting with cubic spline curve fitting of multi backplanes’ space, is proposed for computer-aided manufacturing (CAM) software design. Finally, the proposed processing method and CAM model algorithm are proved to be effective through the simulation and actual verifications, the products meet the processing requirements and the processing time of each piece is reduced from 8 to 2 min, and they also greatly improve the production automation and achieve energy saving and emission reduction. 相似文献
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Mohammad Jafar Haddad Fereshteh Alihoseini Mostafa Hadi Meysam Hadad Alireza Fadaei Tehrani Aminollah Mohammadi 《The International Journal of Advanced Manufacturing Technology》2010,46(9-12):1119-1132
The cylindrical wire electrical discharge turning (CWEDT) process was developed to generate precise cylindrical forms on hard, difficult to machine materials. A precise, flexible, and corrosion-resistant submerged rotary spindle was designed and added to a conventional five-axis CNC wire electrical discharge machine (EDM) to enable the generation of free-form cylindrical geometries. The hardness and strength of the work material are no longer the dominating factors that affect the tool wear and hinder the machining process. In this study, the effect of machining parameters on surface roughness (R a) and roundness in cylindrical CWEDT of a AISI D3 tool steel is investigated. The selection of this material was made taking into account its wide range of applications in tools, dies, and molds and in industries such as punching, tapping, reaming, and so on in cylindrical forms. Surface roughness and roundness are chosen as two of the machining performances to verify the process. In addition, power, pulse off-time, voltage, and spindle rotational speed are adopted for evaluation by full factorial design of experiments. In this case, a 22?×?32 mixed full factorial design has been selected considering the number of factors used in the present study. The main effects of factors and interactions were considered in this paper, and regression equations were derived using response surface methodology. Finally, the surfaces of the CWEDT parts were examined using scanning electron microscopy (SEM) to identify the macro-ridges and craters on the surface. Cross sections of the EDM parts were examined using the SEM and microhardness tests to quantify the sub-surface recast layers and heat-affected zones under specific process parameters. 相似文献
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A prototype tool stage with a variable rake angle mechanism has been developed and controlled. The objective of the variable
rake angle mechanism is to provide two-degrees-of-freedom to the conventional noncircular turning process, so that the rotational
tool mechanism can compensate for the rake angle change caused by the noncircular cam profile itself while the translational
tool motion generates the cam profile. Inverse kinematics, kinematic sensitivity and stiffness, and design of the variable
rake angle mechanism are discussed. Robust repetitive controllers are designed for two actuators in the variable rake angle
mechanism. Two actuators operate together to change the tool position as well as the tool angle. Experimental results on the
variable rake angle mechanism support the design concept and control approach. 相似文献
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Dr Y. S. Tarng Y. W. Hseih T. C. Li 《The International Journal of Advanced Manufacturing Technology》1996,11(1):12-17
The paper presents a new spindle speed regulation method to avoid regenerative chatter in turning operations. It is not necessary to analyse complex cutting dynamics to search for stable spindle speeds to eliminate regenerative chatter. The metal removal rate is also greatly improved by using this method. The stability lobe diagram for the stability limit of chip width and chatter frequency versus spindle speed is derived by using the Nyquist stability criterion. It is shown that stable spindle speeds can be automatically obtained when the chatter frequency is found. Computational simulations and experimental cutting tests are performed to illustrate the proposed method. 相似文献
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P. Albertelli V. Mussi M. Monno 《The International Journal of Advanced Manufacturing Technology》2014,72(5-8):1051-1061
Regenerative chatter vibrations generally limit the achievable material removal rate in machining. The diffusion of spindle speed variation (SSV) as a chatter suppression strategy is mainly restricted to academy and research centers. A lack of knowledge concerning the effects of non-stationary machining is still limiting its use in real shop floors. This research is focused on the effects of spindle speed variation technique on tool duration and on wear mechanisms. No previous researches have been performed on this specific topic. Tool wear tests in turning were carried out following a factorial design: cutting speed and cutting speed modulation were the investigated factors. The carbide life was the observed process response. A statistical approach was used to analyze the effects of the factors on the tool life. Moreover, the analysis was extended to the wear mechanisms involved during both constant speed machining and SSV. The worn-out carbide surfaces were examined under a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. Significant differences were appreciated. It was observed that SSV tends to detach the coatings of the inserts, entailing a mechanism that is quite unusual in wet steel turning and thus fostering the wear of the tool. The performed analysis allowed to deduce that the intensified tool wear (in SSV cutting) is mainly due to thermo-mechanical fatigue. 相似文献
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针对最小相位及非最小相位受控系统,分别提出了相应算法,根据系统输出位置信号及输入的控制力信号,辨识出动态切削力信息。不使用测力传感器,从而消除了附加测力传感器所产生的不利因素,为深入研究数控非圆车削加工特性及动态切削力误差补偿提供了一种新手段。 相似文献
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高速加工技术因其加工的优越性,应用越来越普及.从加工优势、机床结构特征及数控系统与编程方面进行阐述. 相似文献
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参数化零件族与参变工艺流程之间的几何关联方法 总被引:3,自引:0,他引:3
为减少零件设计与加工系统设计之间的某些中间环节,缩短产品开发周期,提出了一种在参数化零件族与参变工艺流程之间建立几何关联的方法。该方法首先对一给定的参变工艺流程确定其能够制造的零件集合,即工艺能力包集,用一串特征关系图表示流程中工件与资源的静动态关系,通过不同形式的子图匹配与合并生成能力包集中零件的特征参数模型。然后,比较能力包集和参数化零件族中的零件特征模型,在拓扑同构条件下求解它们的参数等效区域。基于等效区域,建立同时属于能力集合与零件族的零件模型,构成这两零件集合的交集。交集中的零件特征模型同时与参变工艺流程和零件族有几何参数映射关系,从而可作为连接两方面的桥梁,有利于在零件设计与工艺设计之间建立互动关系。 相似文献
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The quality of surface or surface finish is the widely used index of product quality and it is also critical in functional behavior of the products like turbine blades, especially when they are in contact with other medium or the materials. This paper presents the surface quality evaluation of turbine blade steels (ST 174PH, ST 12TE and ST T1/13W) for different combination of cutting parameters viz. speed, feed and depth of cut in a CNC turning process. The response surface method (RSM) is devised in design of experiments and 20 experiments per material are conducted in surface quality evaluation and analysis. The results are analyzed using ANOVA and different graphical methods like contour plot and 3D surface graphs. The reasons for the highest surface roughness of ST 174PH material are analyzed using metallurgical perspective. The regression equations for predicting the surface roughness of the materials are formulated in terms of cutting parameters based on experimental results and are verified using confirmatory experiments. 相似文献
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端盖机械加工工艺的改进 总被引:2,自引:0,他引:2
端盖是机械产品中应用最广泛的零件之一,其加工工艺是否合理,对零件的质量、生产成本影响很大。为此,我们在生产实际中不断总结经验,改进了该零件的加工工艺。本文通过对端盖的功用及结构特点、原工艺的缺陷、现行工艺的特点等三个方面的分析,深入研究端盖的机械加工工艺。 相似文献
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Adam G. Rehorn Jin Jiang Peter E. Orban Evgueni Bordatchev 《The International Journal of Advanced Manufacturing Technology》2004,24(11-12):806-815
The geometric quality of high-precision parts is highly dependent on the dynamic performance of the entire machining system, which is determined by the interrelated dynamics of machine tool mechanical structure and cutting process. This performance is of great importance in advanced, high-precision manufacturing processes, including aerospace and biomedical applications. In this paper, the dynamics of the combined spindle/cutter system, a major component of any machine tool, is identified using impact testing techniques and is successfully approximated by a second-order linear model. Results of computer simulations of machining processes that include the identified spindle/cutter dynamics show a significant influence on the quality of the final product. From this, it is concluded that, for precision workpieces, the dynamics of the spindle and cutter system will have to be taken into account in order to improve future machining controls and processes. 相似文献
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Mehmet Alper Sofuoğlu Fatih Hayati Çakır Selim Gürgen Sezan Orak Melih Cemal Kuşhan 《The International Journal of Advanced Manufacturing Technology》2018,95(1-4):83-97
Ultrasonic-assisted machining is a machining operation based on the intermittent cutting of material which is obtained through vibrations generated by an ultrasonic system. This method utilizes low-amplitude vibrations with high frequency to prevent continuous contact between a cutting tool and a workpiece. Hot machining is another method for machining materials which are difficult to cut. The basic principle of this method is that the surface of the workpiece is heated to a specific temperature below the recrystallization temperature of the material. This heating operation can be applied before or during the machining process. Both of these operations improve machining operations in terms of workpiece-cutting tool characteristics. In this study, a novel hybrid machining method called hot ultrasonic-assisted turning (HUAT) is proposed for the machinability of Hastelloy-X material. This new technique combines ultrasonic-assisted turning (UAT) and hot turning methods to take advantage of both machining methods in terms of machining characteristics, such as surface roughness, stable cutting depths, and cutting tool temperature. In order to observe the effect of the HUAT method, Hastelloy-X alloy was selected as the workpiece. Experiments on conventional turning (CT), UAT, and HUAT operations were carried out for Hastelloy-X alloy, changing the cutting speed and cutting tool overhang lengths. Chip morphology was also observed. In addition, modal and sound tests were performed to investigate the modal and stability characteristics of the machining. The analysis of variance (ANOVA) method was performed to find the effect of the cutting speed, tool overhang length, and machining techniques (CT, UAT, HUAT) on surface roughness, stable cutting depths, and cutting tool temperature. The results show both ultrasonic vibration and heat improve the machining of Hastelloy-X. A decrease in surface roughness and an increase in stable cutting depths were observed, and higher cutting tool temperatures were obtained in UAT and HUAT compared to CT. According to the ANOVA results, tool overhang length, cutting speed, and machining techniques were effective parameters for surface roughness and stable cutting depths at a 1% significance level (p ≤ 0.01). In addition, cutting speed and machining techniques have an influence on cutting tool temperature at a 1% significance level (p ≤ 0.01). During chip analysis, serrated chips were observed in UAT and HUAT. 相似文献