涂层刀具高速铣削高硬度淬硬钢的振动研究

高硬度淬硬钢高速铣削过程具有高铣削速度和高加工表面硬度的特性,平稳高效的铣削能保证加工质量和精度,铣削振动的产生限制了硬态切削技术优越性的发挥.通过设计在不同加工工艺参数条件下涂层刀具高速铣削高硬度(HRC 48～68)淬硬钢试验,使用LMS Test9A测试分析软件采集铣削振动信号,进行时域和频域分析,研究铣削振动与...     

涂层刀具高速铣削高硬度淬硬钢切削力研究

采用四种不同涂层硬质合金铣刀高速铣削四种不同硬度的淬硬钢材料,研究了刀具涂层成分、工件材料硬度以及切削工艺参数(切削速度、每齿进给量、轴向铣削深度和径向铣削深度)对切削力的影响。研究表明：随着切削速度的增大,淬硬钢P20和S136的切削合力影响较小,而对于淬硬钢SKD11和PM60,改变切削速度对切削合力影响显著。随着切削速度的增大,四种不同涂层刀具切削淬硬钢S136产生的切削合力先快速增大后缓慢减小,刀具切削力大小顺序一直保持为TiSiN>CrSiN>AlCrN>TiAlN,其中TiAlN涂层相对于其余三种刀具涂层在降低切削力、减少工件与刀具之间的相互摩擦具有优势。切削参数的变化对切削力的影响与淬硬钢工件硬度的变化存在相互影响,淬硬钢硬度低于HRC55时,切削工艺参数的变化对于切削力的变化影响不明显;而当淬硬钢硬度高于HRC60时,随着切削工艺参数的增大,切削力发生显著变化。     

高速铣削淬硬钢时切削载荷平稳化研究

和传统的铣削加工相比,高速铣削淬硬钢更需要稳定的切削载荷,以尽可能减少刀具碎裂和过度磨损。本研究借助三向压电石英测力仪,使用TiAlN涂层球形端铣刀,在13500 r/min的转速下,对淬火45#钢(47HRC~48HRC)进行了高速铣削试验,建立了高速铣削下的多项式切削力试验模型,模拟了以恒定切削力为目标、优化进给率的加工实例。结果显示,稳定的切削载荷能有效地提高加工效率,避免刀具剧烈磨损。     

淬硬钢高速铣削试验研究

针对淬硬钢选择了Cr12MoV进行了高速铣削研究,重点研究了铣削力、刀具对铣削过程的影响。结果表明：铣削方式、刀具螺旋角以及润滑方式对铣削力、刀具磨损的影响是不同的;随铣削速度的增加铣削力呈明显上升趋势。高速铣削刀具后刀面磨损,伴随加工的整个过程。淬硬钢高速铣削加工既可以保证加工表面的质量,又可以获得较高的生产效率。     

淬硬钢的高速、高精度硬切削

聚晶立方氧化硼(PCBN)刀具代替磨削刀具使用于硬加工,但是由于加工过程中安全性的缺点到目前尚不能用于淬硬钢的高速和高精度加工。现在新开发的刀刃材料和变化的进给速度新工艺使这类刀具的应用成为可能。     

淬硬钢的高速切削加工

淬硬钢以其优良的使用性能在模具行业中占着非常重要的地位，随着高速加工中心在我国的应用的增加，高速加工已成为淬硬钢管等高硬度材料切削加工的主要手段。本文首先介绍了淬硬钢高速加工的概况，针对使用涂层刀具淬硬钢时出现的具体问题，结合实际研究分析了切削刀具，加工工艺参数和走刀方式等对加工过程的影响，并提出一些实际加工中应注意的问题，改善加工条件和提高加工质量的方法。     

淬硬钢高速切削加工技术研究

淬硬钢高速铣削加工具有传统加工无可比拟的优势,是淬硬钢加工的发展方向.从切削刀柄和刀具、加工工艺、数控编程等方面阐述了淬硬模具钢高速加工的技术特点.     

淬硬钢高速铣削用量确定方法的研究

采用高速铣削技术加工淬硬钢可以大大改善材料去除率和表面粗糙度,并提高淬硬钢加工效率,降低加工成本.为获得必要的加工精度、表面质量及延长刀具寿命,铣削淬硬钢材料除精心选择刀具材料和几何参数外,必须优化铣削用量.基于淬硬钢高速铣削参数对铣削力影响的理论分析,得出高速铣削淬硬钢宜采用高转速、低进给、小切深的方式进行铣削加工的结论.比较分析了确定淬硬钢高速铣削用量的常用3种方法.     

淬硬钢高速铣削参数优化试验研究

采用正交试验法对切削力和粗糙度两个试验指标进行优化,最后采用综合平衡法确定出一组最优方案。经验证满足加工要求,达到了试验目的。     

高速铣削淬硬钢的研究进展

对国内外高速铣削淬硬钢的研究成果进行评述.讨论高速切削的概念和特点、切削力、金属软化效应、涂层刀具加工淬硬钢的切削性能、切屑形成机理、冷却方式以及对加工表面的影响,并提出高速铣削淬硬钢研究中的热点问题.     

Elliptical vibration cutting of hardened die steel with coated carbide tools

Elliptical vibration cutting of hardened die steel with coated carbide tools is examined in this research in order to achieve low-cost high-precision machining. Diamond coated tools are applied because of superior hardness of their polycrystalline diamond coating and its low manufacturing cost. TiN coated tools are also tested, since they are widely used for conventional machining of steels. Machinability of hardened die steel by the elliptical vibration cutting with coated carbide tools is discussed in three aspects in this study, i.e. transferability of cutting edge profile to cut surface, cutting force, and tool life. The transferability is evaluated quantitatively by calculating correlation coefficients of measured roughness profiles. It is clarified that the diamond coated tools have high transferability which leads to diffraction of light on the surface machined at micro-scale pick feed. Total cutting forces including ploughing components are measured at various feed rates, and then shearing components and ploughing components are separated utilizing linear regression. The measured results indicate, for example, that the all forces become considerably smaller only when elliptical vibration is applied to the TiN coated tool without cutting fluid. It is also found that this considerable reduction of forces interestingly corresponds to higher friction coefficient, which is identified from the ploughing components. Tool life tests are carried out by various machining methods, i.e. elliptical vibration/ordinary wet/dry cutting with diamond/TiN coated tools. The result shows, for example, that the flank wear is smallest in the wet elliptical vibration cutting with the diamond coated tool.     

Cutting performance of coated carbide tools in high-speed face milling of AISI H13 hardened steel

In the present study, high-speed face milling of AISI H13 hardened steel was conducted to investigate the cutting performance of coated carbide tools. The characteristics of chip morphology, tool life, tool wear mechanisms, and surface roughness were analyzed and compared for different cutting conditions. It was found that as the cutting speed increased, the chip morphology evolved in different ways under different milling conditions (up, down, and symmetric milling). Individual saw-tooth segments and sphere-like chip formed at the cutting speed of 2,500 m/min. Owing to the relatively low mechanical load, longest tool life can be obtained in up milling when the cutting speed was no more than 1,000 m/min. As the cutting speed increased over 1,500 m/min, highest tool life existed in symmetric milling. When the cutting speed was 500 m/min, owing to the higher mechanical load, the flaked region on the tool rake face in symmetric milling was much larger than that in up and down milling. There was no obvious wear on the tool rake face at the cutting speed of 2,500 m/min due to the short tool-chip contact length. In symmetric milling, the delamination of tool material, which did not occur in up and down milling, was caused by the relatively large cutting force. Abrasion had great effect on the tool flank wear in symmetric milling. With the increment of cutting speed, surface roughness decreased first and then increased rapidly. Lowest surface roughness can be obtained at the cutting speed of about 1,500 m/min.     

Surface roughness analysis of hardened steel after high-speed milling

The work refers to analysis of various factors affecting surface roughness after end milling of hardened steel in high-speed milling (HSM) conditions. Investigations of milling parameters (cutting speed v(c) , axial depth of cut a(p) ) and the process dynamics that influence machined surface roughness were presented, and a surface roughness model, including cutter displacements, was elaborated. The work also involved analysis of surface profile charts from the point of view of vibrations and cutting force components. The research showed that theoretic surface roughness resulting from the kinematic-geometric projection of cutting edge in the workpiece is significantly different from the reality. The dominant factor in the research was not feed per tooth f(z) (according to the theoretical model) but dynamical phenomena and feed per revolution f.     

Cutter path orientations when high-speed finish milling inclined hardened steel

The use of high-speed milling (HSM) for the production of moulds and dies is becoming more widespread. Critical aspects of the technology include cutting tools, machinability data, cutter path generation and technology. Much published information exists on cutting tools and related data (cutting speeds, feed rates, depths of cut, etc.). However, relatively little information has been published on the evaluation of cutter paths for this application. Most of the research focuses on cutter path generation with the main aim on reducing production time. Work concerning cutter path evaluation and optimisation on tool wear, tool life and relevant workpiece machinability characteristics are scant. This paper investigates and evaluates the different cutter path orientations when high-speed finish milling inclined hardened steel, at a workpiece inclination angle of 75°. The results demonstrate that employing a vertical downward orientation achieved the longest life. However, in terms of workpiece surface roughness, vertical upward orientation is generally preferred.     

Prediction of cutting temperature distributions on rake face of coated cutting tools

Coated cutting tools have been widely employed in metal cutting operations owing to its excellent abrasion resistance and heat transfer performances. Rake face temperature is the primary factor that determines the temperature distribution in the cutting tool body. Based on the heat source theory, a new prediction model is proposed in this paper to forecast the temperature distribution on the rake face. Infrared image is used to develop a new turning experimental apparatus to measure the rake face temperature of coated tool during the cutting process. Rake face temperature measurement results are used to verify the proposed model prediction results of temperature distribution. Several cutting tests are carried out with monolayer coated tools in the machining of H13 hardened steel. The rake face temperature in monolayer coated tool for machining H13 shows an increase trend as the cutting speed increases. The influence parameters including thermo-physical properties and tool/workpiece frictional coefficient of coating material on temperature distribution in coated tools are discussed and illustrated. The research results presented in this paper can help to access the potential of coated tools used in the hardened steel machining.     

The effects of cutting parameters on tool life and wear mechanisms of CBN tool in high-speed face milling of hardened steel

High-speed face milling of AISI H13 hardened steel is conducted in order to investigate the effects of cutting parameters on tool life and wear mechanisms of the cubic boron nitride (CBN) tools. Cutting speeds ranging from 400 to 1,600 m/min are selected. For each cutting speed, the metal removal rate and axial depth of cut are fixed, and different combinations of radial depth of cut and feed per tooth are adopted. The tool life, tool wear progression, and tool wear mechanisms are analyzed for different combinations of cutting parameters. It is found that for most of the selected cutting speeds, the tool life increases with radial depth cut and then decreases. For each cutting speed, the CBN tool life can be enhanced by means of adopting suitable combination of cutting parameters. When the cutting speed increases, the normal wear stage becomes shorter and the tool wear rate grows larger. Because of the variations of cutting force and tool temperature, the tool wear mechanisms change with different combinations of cutting parameters even at the same cutting speed. At relatively low cutting speed, in order to acquire high tool life of the CBN tool, the tool material should possess sufficient capability of resisting adhesion from the workpiece. When relatively high cutting speed is adopted, retention of mechanical properties to high cutting temperature and resistance to mechanical impact are crucial for the enhancement of the CBN tool life.