现代金属切削刀具的发展

金属切削技术进入了以高速、高效、高精度为标志的高速切削新阶段,是发展现代制造技术的一项基础工艺。刀具材料的进展和刀具结构的变革是推进高速切削的主要因素。     

金属切削刀具的动向（二）

一、指形铣刀 1.2刃立铣刀在模具加工中最常用的是2刃立铣刀。因为这种铣刀占全部加工时间的比例大,所以它的性能好坏对于模具制造周期的影响很大。最近开发的2刃立铣刀如图1所示,它具有较高的加工效率和加工精度。在普通球形立铣刀加工中,切削刃的切削量是在不断变化的,切削条件差,所以容易产生振动,刀刃的中心部位容易崩刃。 2刃立铣刀的特点是在中心附近的一小段刀刃,由于前面凸起而形成钝角,从而提高了中心部位的刀刃强度,防止了中心部位崩刃。     

金属切削专业合作伙伴——德国豪费德切削刀具

豪费德切削刀具在纽伦堡和佐堡的生产中心通过最现代化的系统和CNC加工设备设计和生产了高标准的精密刀具。     

切削刀具的现状和发展趋势及对策

针对市场上各种新型材料及新结构型式刀具的出现,结合国内低加工制造成本的现实,对未来整个刀具行业将迎来的机遇和市场作出了预期,同时认为新型刀具在生产中的广泛应用,也必将促进高速切削技术的迅猛发展,并通过对切削刀具发展趋势的分析,结合现状提出了对策意见。     

硬质合金刀具在金属切削中的应用优化

硬质合金刀具以其高耐热性、韧性等特点,在金属切削中具有良好的应用价值。分析金属切削原理,明确优化硬质合金刀具应用质量需要严格把控刀具的各项参数。具体加工中,技术人员应根据具体加工需求确定硬质合金刀具材料、结构及其前角、切削刃倾角等参数。为充分发挥硬质合金刀具的应用优势,提出合理选择切削工具材料、充分应用仿真技术、选择适度切削量、抑制与消除积屑瘤以及合理应用切削液等应用措施。     

金属切削刀具后刀面的切削热研究

在以往的金属切削热研究中,认为刀具后刀面处产生的切削热很小而被忽略。文章应用平面热源法,建立了刀具后刀面与工件摩擦面的切削热模型,推导了该摩擦面的切削热分配和切削温度理论计算公式,对影响后刀面切削热的主要因素进行了分析。研究结果表明,当刀具后刀面磨损带宽度达到一定程度时,则刀具后刀面处产生的切削热不能忽略。     

高速切削刀具材料及其与工件匹配研究

实现高速切削加工,刀具材料是关键。目前国内外用于高速切削加工的刀具材料主要有聚晶金刚石(PCD)、立方氮化硼(CBN)、陶瓷、TiCN基金属陶瓷和涂层刀具等。本文介绍了这些高速切削刀具材料各自的特点和应用范围,分析了高速切削刀具材料与工件材料的匹配,并阐述了针对常用工程材料的高速切削加工和刀具材料的合理选择。     

切削淬火钢的刀具及其参数选择

车削高硬度的淬火钢时，可通过合适地选择刀具的材料，几何参数、切削参数，达到理想的切削效果。     

PCD刀具金刚石砂轮刃磨表面质量及其对加工工件表面质量的影响

对树脂结合剂、金属结合剂和陶瓷结合剂金刚石砂轮刃磨PCD刀具的过程特点进行了比较分析,认为陶瓷结合剂金刚石砂轮刃磨PCD刀具可以得到较好的刃磨表面质量且刃磨效率最高;同时对加工工件表面的形成过程进行了分析,认为PCD刀具的后刀面表面质量是最重要的影响因素。     

Hardening Effect on Machined Surface for Precise Hard Cutting Process with Consideration of Tool Wear

During hard cutting process there is severe thermodynamic coupling effect between cutting tool and workpiece, which causes quenching effect on finished surfaces under certain conditions. However, material phase transformation mechanism of heat treatment in cutting process is different from the one in traditional process, which leads to changes of the formation mechanism of damaged layer on machined workpiece surface. This paper researches on the generation mechanism of damaged layer on machined surface in the process of PCBN tool hard cutting hardened steel Cr12MoV. Rules of temperature change on machined surface and subsurface are got by means of finite element simulation. In phase transformation temperature experiments rapid transformation instrument is employed, and the effect of quenching under cutting conditions on generation of damaged layer is revealed. Based on that, the phase transformation points of temperature under cutting conditions are determined. By experiment, the effects of cutting speed and tool wear on white layer thickness in damaged layer are revealed. The temperature distribution law of third deformation zone is got by establishing the numerical prediction model, and thickness of white layer in damaged layer is predicted, taking the tool wear effect into consideration. The experimental results show that the model prediction is accurate, and the establishment of prediction model provides a reference for wise selection of parameters in precise hard cutting process. For the machining process with high demanding on surface integrity, the generation of damaged layer on machined surface can be controlled precisely by using the prediction model.     

颗粒增强复合材料加工表面粗糙度及刀具设计

分析了颗粒增强金属基复合材料的加工表面形貌特点。通过切削试验 ,研究了切削用量和材料组织结构对SiCp/Al已加工表面粗糙度的影响 ,并根据切削表面成形机理及刀具磨损的特征 ,设计了具有引导光整作用的硬质合金刀具。试验结果表明 ,该刀具可显著降低加工表面粗糙度和提高刀具寿命     

刀具表面CVD法金刚石薄膜剥离及其结合性能

在硬质合金和Si3N4陶瓷刀具表面采用热丝CVD法合成金刚石薄膜的结合性能具有明显差异。在沉积金刚石过程中，根据碳源通入系统中的时机不同，硬质合金表面容易形成石墨、WC等松散层，膜的结合性能变差，由于热应力大，在无外力作用下膜有时发生自动剥落现象；而Si3N4陶瓷表面上金刚石膜具有良好结合性能。在压应力作用下，两衬底上的金刚石薄膜剥离过程也不同，硬质合金上膜支接以剥落形式失效，而Si3N4上膜以产生裂纹及其扩展失效。     

钛合金和镍合金加工用新型刀具材料的研究进展

对钛合金和镍合金加工用新型刀具材料的种类、特性等研究现状进行了综合评述,详细阐述了涂层和无涂层硬质合金刀具、聚晶金刚石刀具、立方氮化硼刀具、陶瓷刀具在钛合金和镍合金材料加工过程中的磨损及切削加工后的表面完整性问题,并指出了当前研究中存在的问题和未来的发展趋势。     

刀具工件双旋转运动机床加工过程的能量效率获取方法

对于刀具工件双旋转运动机床,由于切削力测量仪器难以安装,同时,切削力理论模型和经验公式难以反映加工过程切削力的瞬态变化,这使得刀具工件双旋转运动机床的能量效率至今难于获取。为此,提出一种运用载荷损耗系数计算获取刀具工件双旋转运动机床能量效率的方法,该方法首先建立了刀具工件双旋转运动机床的能量效率模型,然后基于刀具、工件系统的能耗组件参数分别建立了刀具轴和工件轴的载荷损耗系数计算模型,并由此推导出刀具工件双旋转运动机床的载荷损耗能量、有效能量及能量效率的计算分析模型。实际应用时,该方法只需要安装功率传感器测取加工过程中的输入功率和空载功率,便可计算获取能量效率。实验验证表明,该方法具有较好的能量效率获取精度。应用案例表明,所提方法应用方便,可为刀具工件双旋转运动机床的能效预测、监控与管理提供技术支撑,具有较好的应用前景。     

A Novel Method for Quantitative Determination of Ultra-low Wear Rates of Materials, Part II: Effects of Surface Roughness and Roughness Orientation on Wear

A novel method of measurement of the very low wear-rates of materials in the ultra-mild wear regime, which involves the use of implanted gold as a marker, was used to understand the effects of surface roughness and roughness orientation on wear under reciprocating sliding conditions. AISI 1095 steel coupons with various Vickers hardness values and different surface roughness and roughness orientation relative to the sliding direction were tested under the same sliding conditions. It was found that parallel sliding causes more wear compared with transverse sliding for the harder samples (Vickers hardness (VH); 450 HV, 650 HV and 1000 HV). Furthermore, the average friction coefficient of parallel sliding is also higher than that of transverse sliding for these samples. Severe wear takes place when the samples are too soft (250 HV), resulting in the complete loss of implanted gold. Surface topographic images were taken before and after the wear tests. It was found that parallel sliding dramatically increases the surface roughness, while transverse sliding does not increase the surface roughness for harder samples (450 HV, 650 HV and 1000 HV). For the soft sample (250 HV), the surface roughness increases significantly under parallel or transverse sliding.