Chip formation in high speed milling of Ti-6Al-4V alloy under nitrogen-oil-mist

High speed milling experiments using nitrogen-oil-mist as the cutting medium were carried out to investigate the characteristics of chip formation for Ti-6Al-4V alloy.Within the range of conditions employed(cutting speed,vc=190-300 m/min;cutting depth of axial,ap=5,7 mm),saw-tooth chips were produced in these experiments.During the macro and micro analysis of the Ti-6Al-4V chips,an optical microscope and a scanning electron microscope(SEM)were used to study the microstructure and the morphology of the chips,and the X-ray photoelectron spectroscopy(XPS)was employed for chemical analysis.Comparisons were made to study the influence of different cutting media(nitrogen-oil-mist,air-oil-mist and dry cutting condition)on chip formation.Results indicate that cutting media have significant effects on chip formation.Nitrogen-oil-mist is more suitable for improving the contact condition at chip-tool interface and increasing the tool life in high speed milling of Ti-6Al-4V alloy than air-oil-mist and dry cutting.

Wear Patterns and Mechanisms of Cutting Tools in High Speed Face Milling

High speed machining has received an important interest because it leads to an increase of productivity and a better workpiece surface quality. However, at high cutting speeds, the tool wear increases dramatically due to the high temperature at the tool-workpiece interface. Tool wear impairs the surface finish and hence the tool life is reduced. That is why an important objective of metal cutting research has been the assessment of tool wear patterns and mechanisms. In this paper, wear performances of PCBN tool, ceramic tool, coated carbide tool and fine-grained carbide tool in high speed face milling were presented when cutting cast iron, 45# tempered carbon steel and 45# hardened carbon steel. Tool wear patterns were examined through a tool-making microscope. The research results showed that tool wear types differed in various matching of materials between cutting tool and workpiece. The dominant wear patterns observed were rake face wear, flank wear, chipping, fracture and breakage. The main wear mechanisms were mechanical friction, adhesion, diffusion and chemical wear promoted by cutting forces and high cutting temperature. Hence, the important considerations of high speed cutting tool materials are high heat-resistance and wear-resistance, chemical stability as well as resistance to failure of coatings. The research results will be great benefit to the design and the selection of tool materials and control of tool wear in high-speed machining processes.

基于PowerMILL Vortex旋风铣与MachineDNA系统应用研究

旋风铣Vortex是Delcam最新的高速区域清除加工策略,可用于2轴、3轴、定位五轴以及残留加工。和传统高速加工方法相比,可节省多达60%的加工时间。Machine DNA是Delcam的一项最新专利技术,它可捕捉单个机床的运行特点和数据,并使用捕捉的数据来完善Power MILL产生的刀具路径[1]。旋风铣Vortex与Machine DNA的结合使粗加工效率提升的同时,最大限度地发挥机床潜能,从而可在合理安全的切削条件下实现加工效率最大化。

Engagement Angle Modeling for Multiple-circle Continuous Machining and Its Application in the Pocket Machining

The progressive cutting based on auxiliary paths is an effective machining method for the material accumulating region inside the mould pocket. But the method is commonly based on the radial depth of cut as the control parameter, further more there is no more appropriate adjustment and control approach. The end-users often fall to set the parameter correctly, which leads to excessive tool load in the process of actual machining. In order to make more reasonable control of the machining load and toolpath, an engagement angle modeling method for multiplecircle continuous machining is presented. The distribution mode of multiple circles, dynamic changing process of engagement angle, extreme and average value of engage- ment angle are carefully considered. Based on the engagement angle model, numerous application techniques for mould pocket machining are presented, involving the calculation of the milling force in multiple-circle continuous machining, and rough and finish machining path planning and load control for the material accumulating region inside the pocket, and other aspects. Simulation and actual machining experiments show that the engagement angle modeling method for multiple-circle continuous machining is correct and reliable, and the related numerous application techniques for pocket machining are feasible and effective. The proposed research contributes to the analysis and control tool load effectively and tool-path planning reasonably for the material accumulating region inside the mould pocket.

Design and Performance Analysis of Small Denture Machining Equipment

The research and application on small denture machining equipment are great breakthrough for modern dental restoration technology. In this paper, a small denture machining equipment made of two spindles with four-axis was designed based on machining characteristics and functional analysis. Position accuracy and re-position accuracy were measured by accuracy instrument. In order to test its machining capacity, some typical microstcucture parts, such as straight channel, hemispherical surface, and molars coronal, were selected for high speed milling. It was obtained that the denture machining equipment met the machining requirements with high quality and efficiency, according to the acquisition and analysis of form and position errors, surface roughness, and 3-D profile.

高速铣削-激光切割机床数控加工高精度控制技术

激光切割机铣削过程中会因工件变形导致表面出现凹凸不平或波浪状,表面局部区域高低不等,致使机床的浮动轴偏离实际运动轨迹,影响工件铣削加工的质量。为此,提出一种高速铣削-激光切割机床数控加工高精度控制技术。采用运动学理论、矩阵转换函数建立激光切割机床运动数学模型,利用PLC控制器、伺服驱动器及电机等搭建激光切割机床高速铣削加工控制模型,使用负反馈控制算法、位移误差函数控制机床铣削加工浮动轴运动,即当浮动轴执行上浮或者下浮运动时,若浮动轴运动轨迹偏离预设轨迹,调节PLC控制器参数来驱动电机控制作业,使其反向运动,直到落在预设轨迹上,实现铣削加工的高精度控制。实验结果表明,所提技术工件的铣削加工质量高,高速铣削过程中上浮点、下浮点控制误差最大值分别为6 mm、6 mm,铣削加工控制的响应时间为6.8 ms。

基于Powermill叶根盘铣刀体的高速数控加工

运用Powermill软件,对盘铣刀刀体进行数控加工研究,并对其加工刀具、加工参数以及数控程序进行优化调试,生成粗、精加工的走刀轨迹、实现在高速铣床上进行机夹式叶根盘铣刀体的数控加工,在保证产品精度的同时,提高了加工效率,降低了制造成本。

Compound machining of silicon carbide ceramics by high speed end electrical discharge milling and mechanical grinding

A compound process that integrates end electrical discharge (ED) milling and mechanical grinding to machine silicon carbide (SiC) ceramics is developed in this paper. The process employs a turntable with several uniformly-distributed cylindrical copper electrodes and abrasive sticks as the tool, and uses a water-based emulsion as the machining fluid. End electrical discharge milling and mechanical grinding happen alternately and are mutually beneficial, so the process is able to effectively machine a large surface area on SiC ceramic with a good surface quality. The machining principle and characteristics of the technique are introduced. The effects of polarity, pulse duration, pulse interval, open-circuit voltage, discharge current, diamond grit size, emulsion concentration, emulsion flux, milling depth and tool stick number on performance parameters such as the material removal rate, tool wear ratio, and surface roughness have been investigated. In addition, the microstructure of the machined surface under different machining conditions is examined with a scanning electron microscope and an energy dispersive spectrometer. The SiC ceramic was mainly removed by end ED milling during the initial rough machining mode, whereas it is mainly removed by mechanical grinding during the later finer machining mode; moreover, the tool material can transfer to the workpiece surface during the compound process.

基于PowerMILL的整体叶轮高效数控加工研究

整体叶轮广泛应用于航空航天、水利水电、汽车等行业的关键零部件中,它的加工质量和精度直接影响产品的性能和价格,所以对整体叶轮的加工制造研究意义重大。在基于Power EMILL软件的基础上,开发出某型号整体叶轮的高效精密制造技术,包括工艺工装、刀轨规划、操作方案等。采用的工装方案能有效避免干涉,使刀具有充足的加工空间;采用"五轴定位"模式加工流道,大大提高叶轮工件的开粗加工效率;使用"SWARF精加工"策略实现刀具的侧刃加工等,经验证采用该工艺工装及刀轨策略能有效提高叶轮的加工效率和精度。

基于粉碎齿刀具的吸波蜂窝高速铣削加工试验研究

针对某一典型吸波蜂窝材料,采用粉碎齿刀具在不同切削参数下进行高速铣削试验,从切削力、加工表面质量、切削功率、切削温度等角度分析铣削参数对加工过程参量的影响规律,进而确定吸波蜂窝高速铣削的优化工艺参数。研究表明,提高切削速度有利于降低切削力和改善表面加工质量,当进给速度、切削深度或切削宽度增大时,因单位时间内材料切除体积增大,导致切削力和切削温度升高,造成表面缺陷加剧。以抑制毛刺缺陷形成为主要目标时,综合考虑工艺参数对切削力、切削功率和切削温度的影响,推荐优化工艺参数为主轴转速16000 r·min^(-1)、进给速度4000 mm·min^(-1)、切削深度10 mm和切削宽度15 mm。研究结果可为粉碎齿刀具高速铣削吸波蜂窝材料的工艺优化提供数据参考。

基于五轴平台的枞树型轮槽铣刀加工工艺分析

轮槽成型铣刀是加工汽轮机轮毂槽的重要工具,其结构复杂且加工困难。为提高加工效率和精度,以某型高速钢轮槽铣刀为例,提出基于五轴平台的加工工艺方法。使用UG软件基于五轴车铣复合机床规划粗加工刀具路径,并采用专用后置处理器生成数控加工程序,通过虚拟机床进行仿真验证;采用NUMROTO软件规划精加工路径,获得磨削NC代码并进行虚拟加工验证;进行实际切削验证,通过DOOSAN PUMA SMX2600ST车铣复合加工中心对刀具进行粗加工后,在SAACKE UWIF五轴工具磨床上完成刀具的精加工。实验结果证明,该工艺方法不仅能保证产品质量符合工艺设计要求,而且制造效率提高了20%。

基于PowerMILL的龙凤铜碗五轴加工技术

介绍了龙凤铜碗的结构特点,讨论了其加工方法及工艺,解决了反面加工时的装夹难题,基于PowerMILL软件对其进行了五轴编程,应用DMU40五轴联动高速机床完成了产品的加工。

MASTER CAM动态铣削在数控铣削中的应用研究

该文针对数控铣开粗效率较低,如何提高数控铣开粗效率,降低生产成本进行研究。经过多次试验实践比较,采用MASTER CAM动态铣削方法,通过对其加工方式方法、参数优化等分析研究与应用,得到使用动态铣削加工的方法。MASTER CAM动态铣削方法可以大幅提高加工效率,解决因铣削过程中切深较大,导致主切削力增加,切削温度升高,使刀具损坏或工件变形的情况发生,同时延长刀具使用寿命。此方法在保证零件加工精度的同时,正真做到高速、高效、高精的“三高”实践。操作简单,可充分发挥机床、刀具等性能,进一步为企业节约生产成本,扩大盈利,值得全面推广和借鉴,为数控铣高速、高效加工提供一定的参考依据。

五角星徽章模型的Power MILL高速加工应用探讨

以五角星徽章模型作为典型例子,在Power MILL软件里实现高速加工模拟仿真,并在加工策略中引用赛车线、摆线加工等高速加工方式,使加工路线更安全合理。

高端液压支架结构件的板件铣削工艺研究

当前液压支架工作阻力越来越大、支护高度越来越高,其整体强度和刚度直接受到零件粗糙度、平行度、尺寸公差等因素的影响。通过对液压支架结构件关键零件的尺寸公差、粗糙度、形位公差和机械加工定位基准等的研究,确定了高端液压支架板件铣削加工的关键控制点并为提高液压支架板件铣削质量制定一系列措施,为液压支架部件的拼装间隙、焊接质量、结构件整体稳定性的提升提供技术参考。

1450二十辊轧机机架梅花孔加工技术与应用

介绍了1450 mm森吉米尔二十辊轧机机架的结构特征和精度指标,对机架关键部位梅花孔的加工工艺装备、工艺方法、检测方法、表面质量控制措施以及影响加工精度的因素进行了研究。考虑刀具磨损、环境温度、切削热等因素对加工质量的影响,通过选择合理的加工设备、改进工艺方法、优化切削参数、设计制作专用研磨工装等措施,采用激光跟踪仪检测机架梅花孔的尺寸及形位精度,实现了1450 mm二十辊轧机机架高精度梅花孔的加工及检测。

高精度模具加工技术在机械制造中的应用

高精度模具加工技术作为先进制造业的重要支撑,在机械制造领域发挥着关键作用。通过对精密铣削、电火花加工和激光加工等技术的应用分析,可实现模具加工精度和表面质量的显著提升。实验表明,采用五轴联动加工中心结合超硬刀具,可将模具表面粗糙度降至Ra 0.2μm以下;采用电火花加工与激光技术的复合应用,使得微细结构加工精度提高了30%。这些技术的综合运用不仅提升了模具寿命,还大幅缩短了产品开发周期,为机械制造业的高质量发展提供了有力支撑。

基于不同细骨料体系水工混凝土性能研究

为研究不同细骨料体系对水工混凝土性能的影响,在II区中砂颗粒级配下,分别采用河砂、机制砂、混合砂配置3组水工混凝土拌合物,并对其开展了工作性能、力学性能和耐久性能的对比分析研究。研究结果表明:在同等条件下,采用不同细骨料体系配置水工混凝土拌合物,混凝土工作性能、力学性能和耐久性能有明显不同;“高品质机制砂+球磨机制砂”配置的水工混凝土综合表现最优,说明机制砂完全可以替代河砂作为细骨料应用于水工混凝土的生产,并且使用高品质机制砂制备混凝土性能相比河砂更优。

地层综合探测技术在隧道铣挖法施工中的应用

隧道悬臂掘进机铣挖法是低扰低振限制环境条件下石质隧道暗挖首选方案,围岩地层条件是悬臂掘进机选型以及确定施工工艺的决定性因素,常规钻芯取样地勘工作不能满足铣挖法掘进施工地层适应性分析判断需要。在钻芯勘探的基础上应用地震勘察折射波法+高密度电法+超声波测井法等地层综合探测技术,结合工程实例介绍了测线布置、探测解译过程,实现了对隧道穿越地层围岩的物理力学性质、围岩级别、围岩完整性及岩体节理裂隙发育程度等的精细化探测,保证了隧道铣挖法施工的顺利进行。

基于Delcam软件中PowerMILL加工技术的应用

PowerMILL是Delcam开发的一个独立运行的高速CAM系统。