高速切削Inconel 718刀具磨损形态和机理分析

利用涂层硬质合金刀具对Inconel 718进行了高速干切削试验,采用扫描电子显微镜SEM和能量分散光谱EDS扫描,对不同切削参数下刀具的损坏形态和损坏机理进行了研究。分析结果表明刀具损坏形式主要有前刀面磨损、后刀面磨损、剥落和崩刃。刀具损坏机理主要是粘结磨损、磨粒磨损、氧化磨损和扩散磨损等。     

刀具损坏形态的识别和控制

操作工人需要掌握刀具方面的知识,便于识别刀具的磨损型式和选择适当的刀具。在每次更换刀具时,磨损的刀具都用电视摄像机检查,并用图像识别技术对刀具损坏形态进行分类。当出现不合乎要求的形态时,应根据事先准备好的判定表中的数据改变刀具材料和刀具形状,而该判定表是根据试验方法确定的。实践证明,在车削操作中采用这种方法能有效地区分刀具的损坏形态并加以控制。     

陶瓷刀具和PCBN刀具磨损形态的研究

对陶瓷刀具(CC650)和PCBN刀具(CB20)精车淬硬GCr15轴承钢时的刀具磨损形态及性能进行了对比试验；结合扫描电镜对刀具的磨损形态作观察；分析了刀具磨损特征及磨损机理。结果表明：刀具损坏的形态主要为前刀面磨损、后刀面磨损、微崩刃及破损等；陶瓷刀具和PCBN刀具的前后刀面磨损形态不同于典型的磨损形态，陶瓷刀具主后刀面的磨损量要比PCBN刀具的磨损量小。但两种刀具均适合于淬硬钢的精加工工序。     

刀具表面微织构的设计制造及其对摩擦特性的影响

刀具的损坏形式主要有磨损和破损,研究发现,磨损损坏形式在刀具损坏中的比例高达70%。为了减缓和降低刀具的摩擦强度,延长并提升刀具寿命,本文基于仿生学原理,通过纳秒激光器在刀具表面加工沟槽织构,改变刀具表面的结构和形态。探究激光参数对微织构尺寸和形貌的影响,确定加工微织构的最优激光参数。在此基础上,分析干摩擦条件下不同面积占有率的正弦型沟槽织构刀具在不同载荷和摩擦速度条件下的减摩机理。     

仿生物体表非光滑微织构形态刀具应用及发展

刀具磨损是金属切削加工业遇到的主要问题。提高刀具耐磨性能,能够有效改善加工零件表面质量,减少机床损坏,降低加工成本。为此,在刀具表面上构造仿生物体表非光滑微织构形态,能够改善刀具耐磨性能,实现绿色切削加工。介绍了仿生物体表非光滑形态的种类,归纳了仿生物体表非光滑形态微织构刀具的耐磨机理、织构类型、织构排布形式、切削质量等方面的研究概况。研究结果表明,有效利用某些生物体表面存在的非光滑微织构形态,能大幅度提高刀具耐磨性能。提出并分析了当前仿生物体表非光滑织构形态刀具研究中尚待解决的一些关键性问题,并给出相应的解决办法。这些研究将为提高刀具耐磨性能提供一种新的发展方向。     

刀具损坏形式计算机辅助分析系统的开发

设计开发了刀具损坏形式计算机辅助分析系统 (TFP CAAS)。应用该系统可根据刀具损坏形式迅速、准确地查到刀具损坏 (包括磨损和破损 )原因 ,并提出相应的解决方案     

基于车铣技术的刀具磨损和破损分析

在车铣加工中心上，分别采用硬质合金和TiN涂层硬质合金刀片，对铝合金和不锈钢工件进行了车铣加工的刀具磨损试验，研究分析了车铣刀具的磨损和破损特征。研究表明，车铣铝合金的刀具磨损机理主要以刀具表层材料的黏结磨损为主，而车铣不锈钢的刀具磨损机理主要以刀具表层材料的疲劳-剥落磨损为主。车铣不锈钢时，刀具的损坏形式常常以微崩刃、前刀面的剥落和碎断等破损形态为主。     

在数控机床上通过监视主轴电机负荷实时监控刀具寿命

金属切削刀具的磨损和损坏直接影响到加工质量,因此有必要在生产实践中对刀具进行实时监控。刀具磨损或损坏时,切削力会发生变化,主轴电动机负荷也会发生变化,因此,可以根据主轴电动机负荷判断切削刀具是否到达寿命。本文探索了一种在数控机妹上通过监视主轴电动机负荷实时监控刀具寿命的方法,并给出了具体的实现技术及PLC和CNC程序。     

Al2O3基陶瓷刀具车削300M超高强度钢的刀具寿命研究

采用对角正交回归试验法,求得Al2O3基陶瓷刀具切削300M超高强度钢的刀具寿命经验公式,并分析了切削用量对刀具寿命的影响.通过扫描电子显微镜的观察和能谱分析仪的分析,对Al2O3基陶瓷刀具的损坏形态和磨损机理进行了研究.研究表明:Al2O3基陶瓷刀具车削300M超高强度钢时,粘结磨损和磨粒磨损是主要的磨损机理;合理的切削参数为:切削速度200～300 m/min、切削深度0.1～0.15 mm、进给量0.05～0.1 mm/r.     

盾构机掘进中刀具损坏及维修措施

隧道工程掘进施工中,盾构机性能的稳定性直接影响掘进施工的效果。特别是在较硬的地段施工时,盾构机功能是否可以稳定发挥决定着隧道施工是否能保质保量完成。隧道掘进施工中,往往会给刀具、刀盘等带来一定的损害,掌握盾构机刀具损坏及维修管理措施,有助于促进隧道掘进施工顺利有序完成。介绍刀具损坏给盾构施工带来的影响,论述刀具损坏形式,就刀具检查、更换、维修等工作进行了全面的分析。     

Evaluation of the Machinability of Nickel-Base,Inconel 718, Alloy with Nano-Ceramic Cutting Tools

The machinability of difficult-to-cut aerospace alloys can be enhanced by the rapid development of cutting tool materials that can withstand machining at high-speed conditions. The performance of nano-grain size ceramic tool materials were evaluated when machining nickel base, Inconel 718, in terms of tool life, tool failure modes and wear mechanisms as well as component forces generated under different roughing conditions. Comparison tests were carried out with commercially available ceramic tool materials of micron-grain composition.

The test results show that the micron grain size commercially available tool materials generally gave the longest tool life. The dominant failure mode is nose wear, while some of the nano-ceramic tools were rejected mainly due to chipping at the cutting edge. This suggests that physical properties and mechanical stability of the cutting edge of the ceramic tools influence their overall performance. It is also evident that chemical compositions of the tool materials played a significant role in their failure. The alumina base ceramics are more susceptible to premature fracture than the silicon nitride base ceramics with higher fracture toughness.     

低温氮气射流对钛合金高速铣削加工性能的影响

在钛合金的高速切削过程中，切削区温度很高，加速了刀具的磨损，限制了切削速度的进一步提高。为降低切削区温度、防止刀具的氧化磨损，提出在低温氮气射流条件下进行钛合金的高速铣削加工。在干铣削、浇注切削液、常温氮气油雾、低温氮气射流和低温氮气射流结合微量润滑等冷却润滑条件下进行了钛合金的高速铣削对比试验。试验结果表明，低温氮气射流结合微量润滑能够最有效地降低铣削力，抑制刀具磨损。借助扫描电镜的检测手段，研究了不同冷却润滑条件下刀具的失效形式。指出在低温氮气射流条件下高速铣削钛合金时，只要热裂纹的形成与扩展未引起刀具的崩刃及刀面的剥落，进一步降低低温氮气的温度将提高刀具的使用寿命。     

高温合金NiCr20TiAl钻削加工特性研究

高温合金是金属材料中最难加工的材料之一,使用M42高性能高速钢非涂层麻花钻,对变形高温合金材料NiCr20TiAl进行钻削加工.通过改变切削参数和冷却条件,对切削加工过程中刀具的寿命、切屑形态和刀具失效机理进行了试验研究.结果表明,高性能高速钢M42麻花钻主要的失效方式是后刀面磨粒磨损、粘结磨损、扩散磨损、沟槽磨损和崩...     

Extensive risk analysis of mechanical failure for an epiphyseal hip prothesis: a combined numerical-experimental approach

There has been recent renewed interest in proximal femur epiphyseal replacement as an alternative to conventional total hip replacement. In many branches of engineering, risk analysis has proved to be an efficient tool for avoiding premature failures of innovative devices. An extensive risk analysis procedure has been developed for epiphyseal hip prostheses and the predictions of this method have been compared to the known clinical outcomes of a well-established contemporary design, namely hip resurfacing devices. Clinical scenarios leading to revision (i.e. loosening, neck fracture and failure of the prosthetic component) were associated with potential failure modes (i.e. overload, fatigue, wear, fibrotic tissue differentiation and bone remodelling). Driving parameters of the corresponding failure mode were identified together with their safe thresholds. For each failure mode, a failure criterion was identified and studied under the most relevant physiological loading conditions. All failure modes were investigated with the most suitable investigation tool, either numerical or experimental. Results showed a low risk for each failure scenario either in the immediate postoperative period or in the long term. These findings are in agreement with those reported by the majority of clinical studies for correctly implanted devices. Although further work is needed to confirm the predictions of this method, it was concluded that the proposed risk analysis procedure has the potential to increase the efficacy of preclinical validation protocols for new epiphyseal replacement devices.     

发动机钻孔加工中钻头崩刃及断刀问题解析

对机加工中常见的钻头失效模式进行了总结和分析,从深孔加工、倾斜表面钻孔、钻孔的冷却与润滑等方面结合钻头使用的相关原则,对发动机生产领域的钻头失效的案例进行解析.钻头选择及使用时背离了这些基本原则往往会导致钻头的异常磨损、崩刃、断刀,钻头失效的解决需从这些基本原则入手和分析.     

基于突变论的刀具寿命建模与预报的研究

介绍了基于突变论的方法建立刀具磨损与破损失效寿命模型的可行性的研究结果。借助于最小二乘回归，建立了变参数三次多项式车／立铣刀具磨／破损融合模型。利用这一模型完成了一种车／立铣监视系统。实验结果表明，监视刀具磨损和破损的成功率≥９５％，刀具磨损值的预报误差≤１０％。叙词     

Economic analysis of machining including a consideration of tool life scatter

Scatter in the wear rate and sudden fracture are often concomitant causes of premature tool failure. To control the economics of a machining process the related cutting conditions require to be selected according to a balanced estimate of expected results. Some mathematical relations including these modes of tool decay have been applied to newly established optimization procedures valid for the main economic objectives. The fundamentals of these techniques are briefly described and their implementation in machining economics is illustrated.     

基于决策实验室法的电主轴失效模式优先级分析

系统的失效模式优先级分析对系统的可靠性设计和可靠性分配具有重要的指导意义。电主轴作为现代高速精密机床的核心部件,要求具有较高的可靠性和更长的寿命。本文中应用决策实验室分析法,充分考虑了失效模式间的联系以及影响程度,对电主轴系统的主要失效模式进行了优先级分析,并结合与传统的风险优先数法的比较,为提高电主轴系统的可靠性和寿命提出了失效模式的优先次序意见。     

纳米TiN改性的TiC基金属陶瓷刀具切削试验与分析

通过切削试验 ,研究了纳米TiN改性的TiC基金属陶瓷刀具在切削 40Cr和正火态 45钢时的切削性能和失效形式。结果表明 ,该种刀具有良好的切削性能 ,可用于较高速度下钢的切削 ,其主要失效形式为磨损。