共查询到20条相似文献,搜索用时 15 毫秒
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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
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Prolongation of tool life in metal cutting is an effective factor to produce lower cutting forces and better machined surfaces. In this study, the influence of ultrasonic vibration is analyzed using experimental and numerical methods. Accordingly, turning tests are carried out on an AISI 4140 steel bar in two types of machining: conventional and ultrasonic-assisted turning. After verification of the developed model, tool wear results are discussed with respect to analysis of heat and stress distributed on tool faces. Finally, it was revealed that periodic movement of the cutting tool in vibratory turning resulted in reduced contact time, resulting in lower heat conduction from the deformed chip to tool rake face. As a result, lower wear has been propagated on tool faces compared to a tool worn in conventional turning. In addition, the effect of cutting parameters on surface roughness is investigated by measurement and 3D analysis of surface topography. 相似文献
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钛合金高速旋转超声椭圆振动侧铣削切屑特征和刀具磨损研究 总被引:1,自引:0,他引:1
难加工材料钛合金在采用传统铣削方式时,随着切削速度的增加,切削力和切削温度都迅速增加,使得切削条件恶化并加速刀具磨损,从而导致刀具过早失效。将超声椭圆振动加工技术引入到高速铣削中,进行了钛合金高速旋转超声椭圆振动侧铣削试验。从切屑特征以及刀具后刀面磨损两个方面研究了高速超声椭圆振动铣削参数匹配对钛合金加工的影响。首先基于高速超声椭圆振动铣削过程中刀具-工件的运动学特点推导出高速超声椭圆振动铣削加工参数与振动参数间的匹配关系,然后利用本实验室自行研制的超声椭圆振动铣削装置进行了不同参数匹配关系下的验证性切削试验。试验结果表明:合理的参数匹配使得超声椭圆振动铣削在高速条件下依然能够实现分离型断续切削加工。相比普通铣削加工,分离型的高速超声椭圆振动铣削能够获得更加微细的切屑,切削热能够被及时地带走;良好的切削条件使得刀具的后刀面磨损均匀而缓慢,从而延长刀具的使用寿命;高速超声椭圆振动铣削能够有效地提高生产效率。 相似文献
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This paper summarizes the results of thermal finite element simulation and experimental studies of tool temperature in ultrasonic-assisted turning (UAT) of aerospace aluminum using multicoated carbide inserts. At first, mathematical models were developed in order to study the effects of tool coating, rake angle, cutting speed, and feed rate on the friction coefficient. Then with respect to the kinematics of the process, the cutting velocity model would be presented. This velocity model is used in combination with the mathematical model to define the friction coefficient during UAT. The mentioned frictional model is used to write a user subroutine to incorporate the effect of friction coefficient as a function of cutting parameters in the finite element program Abaqus. The results of this simulation make it possible to determine cutting temperature patterns accurately. It is also used to study the effect of cutting parameters (cutting speed, feed rate, rake angle, and vibration amplitude) on UAT. Finally, the simulation results are compared with experimental measurements of cutting temperatures from ultrasonic-assisted turning tests. The results show that ultrasonic-assisted turning is able to lower the maximum cutting temperature in cutting tool, about 29 %, in low feed rates (≈0.14 mm/rev), with a vibration amplitude of ≈10 μm and work velocity of ≈0.5 m/s. 相似文献
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The development of a model used to describe the mechanism by which vibration assisted machining reduces tool temperature is discussed, and correlations to resulting reduction in tool wear are presented. This model is applied to a newly developed ultrasonic, vibration assisted diamond turning device that allows for variation of vibration frequency and vibration amplitude via a direct drive actuator. It accommodates a wide range of vibration parameters, including vibration frequencies up to 40 kHz and amplitudes up to 8 μm, where the tool operates. The model uses the finite element method to predict cutting temperatures under conventional turning conditions (i.e., without vibration assistance). The results from the finite element analysis are then used in conjunction with a model developed for vibration assisted machining to predict the new temperature profiles. The modeling techniques and temperature histories for various vibration conditions are presented as well as experimental results that show the thermal advantages of applying tool vibration. 相似文献
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Taghi Feyzi S. Mohsen Safavi 《The International Journal of Advanced Manufacturing Technology》2013,66(5-8):1025-1030
In this paper, by joining three non-traditional machining methods — plasma-enhanced machining, cryogenic machining, and ultrasonic vibration assisted machining — a new hybrid machining technique for machining of Inconel 718 is presented. Cryogenic machining reduces the temperature in the cutting zone, and therefore decrease tool wear and increases tool life, while plasma-enhanced machining helps to increase the temperature in the workpiece to make it softer. Also, applying ultrasonic vibrations to the tool helps to improve cutting quality and to prolong tool life by lowering, mainly, the cutting force and improving the dynamic cutting stability. This study experimentally investigates the effect of cutting parameters on cutting performance in the machining of Inconel 718 and compares the results of hybrid machining and conventional machining (CM). It is found that the hybrid method results in better surface finish and improves tool life in hard cutting at low cutting speeds as compared to the CM method. 相似文献
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Control of machining zone temperature is achieved by providing effective cooling and lubrication. Though cutting fluids are widely used to carry away the heat in metal cutting, they cannot be recommended in the light of ecological and economic manufacture. Hence, there arises a need to identify eco‐friendly and user‐friendly alternatives to conventional cutting fluids. The present work features a specific study of the application of molybdenum disulphide as solid lubricant for improving tribological properties in turning and to overcome the limitations that arise with the use of cutting fluids or while dry machining. An experimental setup developed has been used to maintain constant flow rate of solid lubricant powder continuously on to the workpiece and tool interface zone. Results are encouraging with overall improvement in machining properties in terms considered parameters as compared to wet and dry techniques, due to the reduction in friction at tool/work and tool/chip interface. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Electrochemical discharge machining (ECDM) is a non-traditional machining process which is used to create micro-features on non-conductive materials. Micro holes and micro channels are the most interested features that have been fabricated by researchers. In recent years, some technical augmentations have been added to the ECDM process to achieve a more efficient machining process, but the employment of each augmentation in the most efficient way is not subjected. In this research, ultrasonic vibration is concentrated on the tool tip which directly and continuously effects on the machining zone and avoids global undesirable effects. For this purpose, modal analysis is used to design a special configuration which achieves the maximum amplitude of vibration in the tool tip. Also, an analytical model is presented for both of the electro-chemical discharge machining (ECDM) and ultrasonic assisted electro-chemical discharge machining (UAECDM) to study the effect of ultrasonic vibration on the thickness of gas film. Practical gas film thickness, machining speed, entrance overcut and tapering zone are studied for both of the ECDM and UAECDM to comprehensive understanding the effect of integration of ultrasonic vibration into the traditional ECDM process. Captures of gas film in different condition confirmed that ultrasonic vibration has reduced the thickness of gas film. Same behavior was achieved by employment of the analytical modeling. As a result, numerous small discharges were achieved which increased the material removal rate (MRR) and hole accuracy, simultaneously. Results showed that ultrasonic vibration can increase MRR up to 82%. Also, tapering zone and entrance overcut deviation as accuracy parameters improved 50% and 40%, respectively. 相似文献
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H13淬硬模具钢精车过程的数值模拟 总被引:4,自引:0,他引:4
采用热力学耦合有限元方法研究了淬硬钢精车过程中切屑形成规律。运用H13 淬硬模具钢流动应力模型进行数值模拟,考查了H13淬硬模具钢精车过程中工艺参数对工件性能和刀具的影响。结果表明:切削速度愈高,进给量愈小,刀具刀尖半径愈大,则工件加工层上的静水拉应力愈小,表面质量愈好; 淬硬钢精车时径向力起主要作用,大于切削力;切削速度愈大,切削力和径向力则愈小,愈有助于改善工件加工层上的表面质量;切削速度、进给量和刀具刀尖圆角半径愈大,工件和刀具温度愈高,愈易导致刀具前刀面扩散磨损和刀具后刀面磨损。研究结论有助于优化H13淬硬模具钢精车过程中工艺参数选择和改进刀具镶片设计。 相似文献
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ABSTRACT The understanding of temperature distribution along the tool-chip interface is important for machining process planning and tool design. Among many temperature modeling studies, uniform heat partition ratio and/or uniform heat intensity along the interface are frequently assumed. This assumption is not true in actual machining and can lead to ill-estimated results at the presence of sticking and sliding. This paper presents a new analytical cutting temperature modeling approach that considers the combined effect of the primary and the secondary heat sources and solves the temperature rise along the tool-chip interface based on the non-uniform heat partition ratio and non-uniform heat intensity along the interface. For the chip side, the effect of the primary shear zone is modeled as a uniform moving oblique band heat source, while that of the secondary shear zone is modeled as a non-uniform moving band heat source within a semi-infinite medium. For the tool side, the effect of the secondary heat source is modeled as a non-uniform static rectangular heat source within a semi-infinite medium; and the primary heat source affects the temperature distribution on the tool side indirectly by affecting the heat partition ratio along the interface. Imaginary heat sources are considered as a result of the adiabatic boundary condition involved along the tool-chip interface and of the insulated boundary conditions along both the chip back side and the tool flank face. The temperature matching condition along the tool-chip interface leads to the solution of distributed heat partition ratio by solving a set of linear equations. The proposed model is verified based on the published experimental data of the conventional turning process and it shows both satisfactory accuracy and improved match. 相似文献
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钛合金由于其出色的机械性能广泛的应用于航空航天结构组件中。但较低的机械加工性使得钛合金切削速度低,即使在使用先进的切削刀具时,也因切削高温而难以进行高速切削加工。断续切削是一种有效地降低切削温度和改善切削质量的方法,作为典型的断续切削方法,传统超声振动切削(Traditional ultrasonic vibration cutting,UVC)和椭圆超声振动切削(elliptical ultrasonic vibration cutting,EUVC)已取得了显著的加工优势。但振动切削临界速度限制了它们的应用仅在低速切削场合。因此一种新的超声振动切削方法被提出,即高速超声振动切削(High-speed ultrasonic vibration cutting,HUVC),此时刀具的振动方向与进给方向平行。当切削速度远远超过UVC和EUVC方法的临界速度时,刀具和工件依旧可以在一定的条件下实现分离。从而HUVC方法实现了宏观上的高速切削和微观上的断续切削,提升了钛合金的切削加工性。首先,HUVC方法的原理在文中给出,随后通过一系列使用普通切削(Conventional cutting CC)方法和HUVC方法的高速切削Ti-6Al-4V合金的对比试验来验证HUVC方法的可行性。试验结果表明,因刀具磨损的显著下降,HUVC方法的刀具寿命可最大提升300%。此外,相比CC方法,HUVC方法的切削效率可以显著提升90%,切削力最大下降50%并在连续的切削加工过程中获得更佳的表面质量。 相似文献
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Y. Peng Z. Liang Y. Wu Y. Guo C. Wang 《The International Journal of Advanced Manufacturing Technology》2012,59(1-4):67-72
The purpose of this paper is to investigate the effects of vibration on the surface and tool wear in scratching of brittle materials. In the past, research methodology of vibration cutting has mainly involved vibrating tool parallel to cutting direction. In this paper, a new approach is proposed by an elliptic ultrasonic vibrating workpiece. It presents the fundamental principles and mechanism of ultrasonic machining together with experimental results of scratching of polysilicon with parallel and vertical ultrasonic vibration assistance. With the elliptic ultrasonic vibration assistance, the brittle material would be more likely to be ductilely removed than in conventional condition, and tool wear could be decreased in scratching of brittle materials. 相似文献
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Evaluation of performance of nanofluid using multiwalled carbon nanotubes for machining of Ti–6AL–4V
Neelesh Kumar Sahu Atul B. Andhare Roja Abraham Raju 《Machining Science and Technology》2018,22(3):476-492
Machining of titanium alloys generate very high temperature in the cutting zone. This results in rapid tool wear and poor surface properties. Therefore, improvement in cutting performance in machining of titanium alloys is very much dependent on effectiveness of the cooling strategies applied. In the present work, performance of nanofluid using multiwalled carbon nanotubes (MWCNTs) dispersed in distilled water and sodium dodecyl sulfate (SDS) as surfactant is evaluated for turning operation on Ti–6Al–4V workpieces. Turning operations were carried out under three different conditions – dry, with conventional cutting fluid and with nanofluid. Nanofluid application was limited to 1 L/h and it was applied at the tool tip through gravity feed. Various machining responses like cutting force, surface finish and tool wear were analyzed while turning at optimum cutting parameters as 150 m/min, 0.1 mm/rev and 1 mm depth of cut. Later on, machining performance of nanofluid is confirmed at low cutting speed of 90 m/min. Nanofluid outperformed conventional cutting fluid with 34% reduction in tool wear, average 28% drop in cutting forces and 7% decrease in surface roughness at cutting speed of 150 m/min. 相似文献
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Xue-Hui Shen Jian-Hua Zhang Hua Li Jin-Jun Wang Xiao-Chen Wang 《The International Journal of Advanced Manufacturing Technology》2012,63(1-4):41-49
The objective of this paper is to investigate the effects of assisted ultrasonic vibration in the operation of micro end milling. Based upon numerical analysis for the trajectory of a tool tip of a two-flute end mill, it was found that the assisted feed direction ultrasonic vibration can achieve separate-type milling that is different from conventional operation by reasonable parameter matching. To validate theoretical analysis and investigate the influence of ultrasonic vibration on milling process, a slot-milling experiment was conducted on an aluminum alloy work piece. The desired ultrasonic vibration was applied in the feed direction by an ultrasonic vibrator. Through investigating and comparing some experimental results involving cutting force, chip formation, surface topography, surface roughness, and machining dimensional accuracy, the authors found that micro end milling with ultrasonic vibration in the feed direction leads to a pulse-like cutting force and produces uniform small chips. Assisted ultrasonic vibration in the feed direction has a negative effect on the surface roughness of the slot bottom, but a positive effect on the dimensional accuracy of the slot width. 相似文献
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为了分析切削参数对刀具温度的影响,以期在加工过程中改善刀具磨损和提高加工质量。采用以断续车削代替铣削加工的仿铣削试验平台,选取热电偶法对断续切削过程中不同切削参数下的后刀面温度进行测量,通过正交试验和单因素试验研究了切削参数对刀具温度的影响。结果表明,在v=200m/min,f=0.15mm/r,a p=0.75mm时,刀具温度最低,切削速度v和进给速度f对刀具温度的影响高度显著,背吃刀量对刀具温度的影响并不显著。在铍铜合金断续切削过程中,刀具温度在v=500m/min出现峰值,随着进给量的增大,刀具温度呈减小趋势,在f=0.11mm/r出现突变的趋势,与后刀面上的热量生成、热源移动和分配等因素的影响密不可分。 相似文献
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超声辅助切削和切削液的联合使用能减小切削力和降低表面粗糙度,试图说明其机理,目的是为开发精密和超精加工技术打下基础。超声辅助切削和切削液的联合使用,从性质上改变了刀刃施加给工件表面的作用力,包括摩擦力和压力:在无切削液情况下,刀刃切入时,前刀面和后刀面施加给被切削面的摩擦力方向是指向刀刃;在有切削液情况下,刀刃切入时,前刀面和后刀面施加给被切削面的摩擦力方向是背向刀刃。背向刀刃的摩擦力,相对于指向刀刃的摩擦力而言,会导致剪切角增大,等效于更锋利的刀刃所产生的剪切角;切削液的存在使得刀刃施加给工件的力更加集中,等效于圆角半径更小的刀刃所能达到的效果;切削液在刀尖部位的压力分布不利于工件表面产生微裂纹。也就是说,超声辅助切削和切削液的联合使用起到了更锋利即更小圆角半径刀刃所起的效果,称之为非物理锐化。 相似文献