共查询到20条相似文献,搜索用时 171 毫秒
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基于DEFORM 2D/3D软件,通过硬质合金平头倒角立铣刀进行高速铣削AISI4340合金钢的仿真实验,在主轴转速1270r/min、进给速度104m/min、切削深度0.1mm的参数下,利用刀具的几何磨损模型和仿真模型模拟了不同刀具磨损类型对切削力与切削热的影响以及刀具二次磨损的主要位置。研究发现,刃口钝化对切削力的影响最大,其次为前后刀面磨损、后刀面磨损和前刀面磨损;后刀面磨损对切削热影响最大,其次为前后刀面磨损、刃口钝化和前刀面磨损。本研究促进了刀具的结构设计的发展和加工工艺的更优选择。 相似文献
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刀具切削温度对刀具寿命、刀具磨损等有重要影响。因此在实际加工之前预测出刀具温度,对合理选择切削参数、优化数控程序等均具有重要意义。平面铣削等断续切削过程的热条件不同于车削等连续切削过程。用数学物理方法建立了平面铣削过程刀具的一维传热学模型,用解析的方法预测平面铣削过程中刀具前刀面的温度分布,考虑了刀具切出时空气强化对流散热对刀具前刀面温度的影响。结果表明,刀具切入时间和切出时间对刀具温度有较大影响。用文献中断续车削刀具温度实验数据对铣削刀具前刀面温度的传热学预测模型进行了验证,结果表明二者趋势一致,但平面铣削预测的刀具温度略低于断续车削的刀具温度。 相似文献
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干式、半干式和低温冷风切削加工技术 总被引:4,自引:0,他引:4
在切削过程中,三个变形区的金属产生弹性变形、塑性变形及摩擦变形,切削功率的99.5%均转变为剪切滑移变形(第一变形区)、前刀面摩擦变形(第二变形区)及挤压、过剩变形、后刀面摩擦变形(第三变形区)所耗能量,并在一瞬间转变为热能,出现切屑、刀具切削刃区域及工件表面温升的现象。 相似文献
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干式、半干式和低温冷风切削加工技术 总被引:3,自引:0,他引:3
切削热是伴随金属切削过程中必然的一种物理现象,对工件质量、刀具寿命有不可忽视的影响。低速切削时,机械磨损是刀具磨损的主要原因;而高速切削时,切削高温诱导刀具的磨损,由机械磨损为主转化为扩散磨损、相变磨损和炭化磨损为主要磨损机理,并引发刀具表面的粘结磨损。切削热还使刀具和工件热膨胀,加剧后刀面摩擦与磨损,引起工件表面粗糙度上升,故超精加工工艺特别强调必须及时、有效地控制切削热在工件、刀具内的传导。控制刀具、工件温升对数控加工有十分重要的意义。 要控制金属的切削热及刀具、工件的温升,必 相似文献
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自由切削法与自由切削刀具 总被引:4,自引:0,他引:4
在深入研究非自由切削的实质和规律性的基础上,揭示实现自由切削的条件,提出自由切削法,其要点是合理刀具的前刀面,以疏导刀刃各部件的排屑,消除排屑干涉,实现自由切削。给出了两种自由切削刀具的原理及其设计方法,分析并实验验证了其优越性。 相似文献
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超精密切削氟化钙单晶金刚石刀具磨损研究 总被引:1,自引:0,他引:1
为了研究氟化钙(CaF2)单晶超精密切削过程中的金刚石刀具磨损及其对切削过程的影响,对CaF2晶体进行了超精密切削实验,系统观测了刀具磨损形貌随切削路程的变化趋势,分析了刀具磨损机理,同时通过分析不同切削路程下切削表面微观形貌和切削力的变化,对刀具磨损与切削模式之间的关系进行了探讨。研究表明,超精密切削CaF2晶体时刀具磨损模式为沟槽磨损和缺口破损,刀具磨损随切削路程的演变过程为后刀面沟槽磨损扩展到前刀面缺口破损,同时相应的切削模式由延性去除转变为脆性去除。该研究结果为大口径CaF2晶体纳米尺度延性域切削提供了技术支持。 相似文献
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1.涂层技术有效改善刀片切削区域性能
金属切削过程中所产生的功率消耗以切削热和摩擦的形式表现出来。这些因素使刀具处于恶劣的加工条件下,表面高负载、高切削温度。之所以产生高温是因为切屑沿刀具前刀面高速滑移,对切削刃产生高压及强烈的摩擦。 相似文献
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基于切削参数和刀具状态的车削功率模型 总被引:2,自引:0,他引:2
动态切削功率建模是切削功率信号用于切削过程监控的关键。本文首次建立了基于切削参数 (主轴转速、进给量、切削深度 (即背吃刀量 )、工件材料及刀具材料 )与刀具状态 (主要考虑后刀面磨损量 )的车削功率模型。试验证明 ,该模型基本能正确反映车削功率信号与刀具状态及各种切削参数之间的关系 相似文献
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丁涛 《中国制造业信息化》2000,29(6):68-69
高速切削加工能够大大提高切削速度 ,提高工件的加工质量和刀具的耐用度。在高速切削条件下 ,材料的切削机理将发生变化 ,切削过程将变得容易 ,切削热将降低。介绍了正在研究和应用的刀夹类型和刀具材料。 相似文献
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In this paper, we propose a practical texture design on the tool flank face for suppressing chatter vibration and flank adhesion. To avoid chatter vibration during cutting, the process damping phenomena can be utilized, where the tool flank face contacts the surface of a finished workpiece to provide a damping effect. As a new technology for an effective process damping, the tool flank texture-assisted technique has been proposed, and its excellent performance in suppressing chatter vibration has been demonstrated. However, issues that can lead to adhesion and tool damage pose challenges from a practical viewpoint. To overcome such issues, this paper proposes new texture geometries that improve the practical performance: parallel line type, vertical line type, and dot type. The results of a series of finite element analyses showed that the effectiveness of process damping depends on the vibration amplitude and wavelength. The proposed flank textures were fabricated on tool flank faces, and turning tests were carried out. The experimental results showed that the proposed tool is stabler than the conventional untextured tool and that it can more effectively improve the critical cutting speed, reduce the vibration amplitude, and decrease the surface roughness after cutting. With the appropriate design of the texture distance, adhesion and tool damage were hardly observed, and a stable and practical cutting could be realized. 相似文献
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朱从容 《中国制造业信息化》2001,30(2):65-66
说明了PCBN刀具的性能特点、制造方法和应用领域 ,并介绍了PCBN刀具在淬硬钢、表面硬化合金、冷硬铸铁、珠光体灰口铸铁材料切削加工中的实际应用情况。 相似文献
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In machining, cutting tools suffer from severe surface wear, especially in the cutting of difficult-to-cut materials. A major cause of tool wear is the friction generated at the tool-work and tool-chip interfaces, which produces a great deal of frictional heat and abrasion. In order to extend tool life and improve the quality of machined components, a host of techniques have been applied to modify the rake and flank faces of cutting tools. These techniques aim at providing cutting tools with improved resistance to external loading, better tribological performance and/or better chemical stability. This article presents a review of the fundamentals behind which the friction and wear in machining are reduced by modifying the cutting tool surface with the commonly used techniques, such as surface coating, high energy beam treatment, and surface texturing. The effects of these surface modifications on improving the cutting performance are also analyzed. Future research directions are finally discussed. 相似文献
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This paper describes the micro cutting of wear resistant tungsten carbides using PCD (Poly-Crystalline Diamond) cutting tools
in performance with SEM (Scanning Electron Microscope) direct observation method. Turning experiments were also carried out
on this alloy (V50) using a PCD cutting tool. One of the purposes of this study is to describe clearly the cutting mechanism
of tungsten carbides and the behavior of WC particles in the deformation zone in orthogonal micro cutting. Other purposes
are to achieve a systematic understanding of machining characteristics and the effects of machining parameters on cutting
force, machined surface and tool wear rates by the outer turning of this alloy carried out using the PCD cutting tool during
these various cutting conditions. A summary of the results are as follows : (1) From the SEM direct observation in cutting
the tungsten carbide, WC particles are broken and come into contact with the tool edge directly. This causes tool wear in
which portions scrape the tool in a strong manner. (2) There are two chip formation types. One is where the shear angle is
comparatively small and the crack of the shear plane becomes wide. The other is a type where the shear angle is above 45 degrees
and the crack of the shear plane does not widen. These differences are caused by the stress condition which gives rise to
the friction at the shear plane. (3) The thrust cutting forces tend to increase more rapidly than the principal forces, as
the depth of cut and the cutting speed are increased preferably in the orthogonal micro cutting. (4) The tool wear on the
flank face was larger than that on the rake face in the orthogonal micro cutting. (5) Three components of cutting force in
the conventional turning experiments were different in balance from ordinary cutting such as the cutting of steel or cast
iron. Those expressed a large value of thrust force, principal force, and feed force. (6) From the viewpoint of high efficient
cutting found within this research, a proper cutting speed was 15 m/min and a proper feed rate was 0.1 mm/rev. In this case,
it was found that the tool life of a PCD tool was limited to a distance of approximately 230 m. (7) When the depth of cut
was 0.1 mm, there was no influence of the feed rate on the feed force. The feed force tended to decrease, as the cutting distance
was long, because the tool was worn and the tool edge retreated. (8) The main tool wear of a PCD tool in this research was
due to the flank wear within the maximum value of Vmax being about 260 μ. 相似文献
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This work presents a systematic and comprehensive investigation of the protective effect of built-up layer (BUL) in dry cutting of stainless steel SUS304. A detailed examination of BUL and built-up edge (BUE) formation conditions, their formation mechanisms, and their protective effect was carried out at different cutting speeds (5–140 m/min), and different feed rates (0.02–0.1 mm/rev). The uncoated cemented carbide tool was used as a cutting tool. The dimensions of BUL/BUE and tool wear were measured by scanning electron microscope (SEM) and laser confocal microscopy (LCM). The protective effect of BUL/BUE was characterized using flank wear progression, as well as crater wear progression, cutting force analysis, and surface roughness analysis. As a result, it was found that BUE forms around the cutting edge at low cutting speeds (5–20 m/min), and BUL, which resembles a water drop, forms on the tool rake face at cutting speeds equal to or above 40 m/min. And a thin layer of flank built-up (FBU) can form on the tool flank face as the cutting speed increases from 40 m/min to 140 m/min. The BUL/BUE formation mechanism was also confirmed. It was revealed that BUL can be considered as a protective layer, which can not only prevent the tool rake face from wear but also decrease the tool flank wear, but BUE can only prevent the crater wear; and to a certain extent, the thin layer of FBU can also work as a protecting layer on the worn tool flank face in dry cutting of SUS304. It was also revealed that the height of BUL plays a very important role in its protective effect. Meanwhile, it was found that BUL and the thin layer of FBU have no or few influences on the amplitude variation of cutting forces and on the surface roughness. These results indicated that BUL can be used to realize the self-protective tool (SPT) in cutting of difficult-to-cut material such as SUS034. In addition, the research also proved that it is necessary to take the influences of BUL, BUE, and FBU formations on tool wear into account in the tool wear model in order to achieve high-precision prediction. 相似文献