PCBN刀具断续切削淬硬钢瞬态冲击力研究

基于正交试验设计方法,使用PCBN刀具进行干式断续车削淬硬钢Cr12Mo V试验,研究了不同切削参数与工件硬度对瞬态冲击力的影响。应用响应曲面法建立了瞬态冲击力的线性预测模型和指数预测模型。研究结果表明:断续切削方式下,工件硬度和切削速度对瞬态冲击力有显著影响;线性预测模型和指数预测模型均能准确地对瞬态冲击力进行预测。     

高速切削过程测温方法综述

切削温度与加工精度和刀具磨损密切相关,高速切削过程中切削温度随着材料,刀具,切削用量的选择不同而呈现出与普通切削过程不同的变化规律.本文归纳了高速切削当中切削温度的测定方法,并指出了各种方法的优缺点及适用性.     

The effect of oil mist supply on cutting point temperature and tool wear in driven rotary cutting

We examined cutting point temperature and tool wear in driven rotary cutting. Cutting tests under dry and minimum-quantity-lubrication (MQL) conditions of stainless steel (SUS304) were carried out. Cutting point temperature was measured using a tool-work-thermocouple method at various cutting speeds. Cutting point temperature tends to increase with increased cutting speed. In driven rotary cutting, cutting point temperature was lower than that of non-rotation cutting. At high-speed cutting of 500 m/min, cutting point temperature was over 1200 °C in the non-rotation tool, but 1000 °C with driven rotary cutting. In addition, when driven rotary cutting was used with MQL, cutting point temperature was decreased to 900 °C. The magnitude of tool wear corresponded almost precisely to cutting point temperature. Severe adhesion on the rake face was observed and resulted in progressive wear on the rake face in rotary cutting at a cutting speed of 100 m/min. The appropriate cutting speed range passively shifts higher from the viewpoint of cutting temperature with rotary cutting.     

Application of thin layer activation to measuring tool wear in metal cutting

Thin layer activation (tla) as a method for measuring tool wear is discussed in the context of previously available methods and shown to be more accurate, quicker and less costly. The concept of tool wear resistance, a function of cutting time and wear, obtained experimentally by tla, is introduced and shown to be a useful aid to determining tool life     

高速切削中切削温度研究方法

切削热与切削温度的产生和影响是高速切削技术研究的重要内容。高速切削过程中的温度检测技术与研究方法是在传统切削速度加工相关技术基础上的发展与创新。归纳了高速切削中切削温度实验测定方法和数值计算方法,指出了各种方法的优缺点及适用性。     

Influence of cutting conditions of cast-metal cutting tools on their wear and durability: Analysis of cutting conditions of tools

The conditions of operation of metal-cutting tools in various applications and of various standard dimensions are analyzed. Long-standing statistical observations at a number of industrial facilities have revealed the dominating mechanisms of wear and the main causes of failure of the tools have been established in response to the conditions of their operation and design features. A range of tools has been selected for comparative durability tests in industrial conditions.     

平面铣削刀具前刀面瞬态切削温度的研究

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。     

硬质合金刀片断续切削时的破损分析

通过切削试验 ,验证了硬质合金刀片断续切削时产生裂纹而导致破损主要是由热应力引起的论点 ,并在试验中观测到断续切削时硬质合金刀具破损的形式主要为切削刃崩刃和前刀面局部剥落。     

纳米硬质合金刀具切削Al/SiC_p复合材料的实验

针对SiC颗粒硬度高,切削Al/SiCp复合材料时刀具磨损剧烈,本文提出用具有较高硬度、韧性及良好抗磨损能力的WC-7Co制备纳米硬质合金刀具,并对Al/SiCp复合材料进行了切削实验。研究了纳米硬质合金刀具磨损机理和Al/SiCp复合材料的切屑去除机理,以及刀尖处后刀面磨损值。研究认为,纳米硬质合金刀具磨损的机理为SiC颗粒的微切削作用引起的磨料磨损,及SiC颗粒对刀尖刃口的高频、断续冲击引起的微崩刃及微破损;Al/SiCp复合材料的切削实质是断续切削;去除机理为切屑的崩碎去除;纳米硬质合金后刀面磨损值较普通硬质合金小30%～50%。实验表明,纳米硬质合金较普通硬质合金更适于加工Al/SiCp复合材料。     

高速干切削加工技术

作为一种新型的绿色制造技术，高速干切削技术对实施人类可持续发展战略有重要的意义.阐述高速干切削加工及其关键技术（包括刀具技术、机床技术和工艺技术等）。     

高速切削技术的发展及应用

高速切削技术已成为切削加工的主流和先进制造技术的一个重要发展方向。高速切削较之常规切削是一种创新的加工工艺和加工理念。分析了高速切削技术的特点，研究了高速切削的关键技术：机床技术、刀具技术和工艺技术，介绍了高速切削技术在航空航天和汽车制造等领域的发展及应用。     

纳米硬质合金刀具切削Al/SiCp复合材料实验

SiC颗粒具有较高的硬度,使Al/SiCp复合材料在切削时刀具磨损剧烈。纳米硬质合金具有较高的硬度、韧性及良好的抗磨损能力。制备了纳米硬质合金刀具WC-7Co,对Al/SiCp复合材料进行了切削实验,研究了纳米硬质合金刀具磨损机理和Al/SiCp复合材料的切屑去除机理,以及刀尖处后刀面磨损值。研究认为,纳米硬质合金刀具磨损的机理为SiC颗粒的微切削作用引起的磨料磨损,及SiC颗粒对刀尖刃口的高频、断续冲击引起的微崩刃及微破损,Al/SiCp复合材料的切削实质是断续切削;Al/SiCp复合材料去除机理为切屑的崩碎去除;纳米硬质合金后刀面磨损值较普通硬质合金小30%~50%。     

Dynamic reliability sensitivity of cemented carbide cutting tool

Influence of geometric and cutting parameters of cemented carbide cutting tool on reliability of cutting tool has become more and more mature, yet influence of its physical and material parameters on reliability is still blank. In view of this, cutting test and fatigue crack growth test of YT05 cemented carbide cutting tool are conducted to measure such data as the original crack size, growth size, times of impact loading, number and time of cutting tool in failure, and stress distribution of cutting tool is also obtained by simulating cutting process of tools. Mathematical models on dynamic reliability and dynamic reliability sensitivity of cutting tool are derived respectively by taking machining time and times of impact loading into account, thus change rules of dynamic reliability sensitivity to physical and material parameters can be obtained. Theoretical and experimental results show that sensitive degree on each parameter of tools increases gradually with the increase of machining time and times of impact loading, especially for parameters such as fracture toughness, shape parameter, and cutting stress. This proposed model solves such problems as how to determine the most sensitive parameter and influence degree of physical parameters and material parameters to reliability, which is sensitivity, and can provide theoretical foundation for improving reliability of cutting tool system.     

高速切削技术发展与应用

介绍了高速切削加工技术,详细分析了高速切削技术的特点,研究了高速切削的关键技术——机床技术、刀具技术、工艺技术及其发展,并对高速切削技术的应用作了简述。     

用解析法计算高速切削单涂层刀具瞬态温度分布

为研究涂层在切削中对刀具温度的影响,为设计刀具涂层提供理论依据,分析高速切削过程中切削热的产生和刀具边界情况,建立单涂层刀具热传导物理模型和数学模型,用数学解析的方法推导出正交高速干切削过程中单涂层刀具体内部的温度分布公式。利用推导出的温度公式对TiN、TiC、Al2O3涂层刀具的切削温度分布进行解析计算,并将解析计算结果与数值分析结果进行比较。结果表明,解析计算结果与数值计算结果吻合很好;涂层材料与基体材料的热物理性能以及涂层的厚度对刀具的温升有重要影响;随着热流密度的增加,涂层厚度对刀具内部的温度影响增大。     

Study of HPHT single crystal diamond as precision cutting tool material

High pressure high temperature (HPHT) synthetic diamond is rapidly replacing natural diamond in precision machining industry due to its consistency in quality and cost. It is believed by some manufacturers that HPHT diamond cutting tool is virtually free of impurities, inclusions and cracks. This paper is to analyze defects inside HPHT diamond crystal by density test, optical microscopy, SEM, Raman, and XRD. Results show that HPHT diamond is relatively clean, with less chemical elements inside in comparison with natural diamond. However, there are cracks, pit holes, and bubbles in/on the crystal, some tracing amount of cementite (Fe₃C), γ-Fe, and nickel based carbides also exist in the HPHT diamond crystal, causing less accurate cutting tool edge and surface integrity. Residual stresses in HPHT diamond are compressive but high in value, may lead to cutting tool brittleness and micro-chipping, which is a common reason for diamond tool failing in precision machining.     

基于刀具的特征动态分解的数控编程方法研究

利用数控加工程序的可重用性,从提高数控编程的质量和效率出发,提出了一种基于刀具特征的动态分解策略。根据企业的产品特点和可用的制造资源,按加工设备对特征进行分类和管理,建立了加工特征库,实现了基于特征的参数化、模块化数控程序生成。与现有的特征建模方法不同,该特征模型不但包括特征几何形状信息,而且定义了刀具选择、路径优化和参数驱动的数控程序生成模块。采用这种方法进行数控工艺设计,可大大缩短数控程序设计时间,提高数控代码的继承性和可重用性。     

车刀双倒棱结构切削效应的仿真分析

以Al-6061铝合金为研究对象,基于Deform有限元分析软件,进行三维切削仿真分析。采用正交试验设计方法,研究车刀双倒棱结构参数对切削力及切削温度的影响规律。仿真试验结果表明,在适当的双倒棱宽度与双倒棱角度下,切削力和切削温度对比单一定值倒棱有明显的减小,研究结果可为倒棱刀具刀尖结构优化和实际切削加工提供理论指导。     

Improved analytical model for residual stress prediction in orthogonal cutting

The analytical model of residual stress in orthogonal cutting proposed by Jiann is an important tool for residual stress prediction in orthogonal cutting. In application of the model, a problem of low precision of the surface residual stress prediction is found. By theoretical analysis, several shortages of Jiann’s model are picked out, including: inappropriate boundary conditions, unreasonable calculation method of thermal stress, ignorance of stress constraint and cyclic loading algorithm. These shortages may directly lead to the low precision of the surface residual stress prediction. To eliminate these shortages and make the prediction more accurate, an improved model is proposed. In this model, a new contact boundary condition between tool and workpiece is used to make it in accord with the real cutting process; an improved calculation method of thermal stress is adopted; a stress constraint is added according to the volume-constancy of plastic deformation; and the accumulative effect of the stresses during cyclic loading is considered. At last, an experiment for measuring residual stress in cutting AISI 1045 steel is conducted. Also, Jiann’s model and the improved model are simulated under the same conditions with cutting experiment. The comparisons show that the surface residual stresses predicted by the improved model is closer to the experimental results than the results predicted by Jiann’s model.     

高速干切削技术及其实现

在切削加工中大量使用切削液进行冷却、润滑,不但提高了加工成本,也带来了环境污染,消除这些问题的合理措施是采用高速干切削方式。提出了干切削技术的新内涵,分析了实现高速干切削的机床技术、刀具技术和工艺技术。通过该技术实现了绿色制造,保证了企业的经济效益和社会效益最优化。