Cutting force and its frequency spectrum characteristics in high speed milling of titanium alloy with a polycrystalline diamond tool

In this paper, a series of experiments were performed by high speed milling of Ti-6.5Al-2Zr-1Mo-1V (TA15) by use of polycrystalline diamond (PCD) tools. The characteristics of high speed machining (HSM) dynamic milling forces were investigated. The effects of the parameters of the process, i.e., cutting speed, feed per tooth, and depth of axial cut, on cutting forces were studied. The cutting force signals under different cutting speed conditions and different cutting tool wear stages were analyzed by frequency spectrum analysis. The trend and frequency domain aspects of the dynamic forces were evaluated and discussed. The results indicate that a characteristic frequency in cutting force power spectrum does in fact exist. The amplitudes increase with the increase of cutting speed and tool wear level, which could be applied to the monitoring of the cutting process.     

Helical milling of CFRP/Ti-6Al-4V stacks with varying machining parameters

The hole-making process in stack materials consisting of carbon fiber reinforced plastics(CFRP) and Ti-6Al-4V remains a critical challenge. In this paper, an experimental study on the helical milling of CFRP/Ti-6Al-4V stacks was conducted by using two different machining strategies. Helical milling strategyⅠ machines both materials with identical machining parameters, while machining strategyⅡ uses two sets of machining parameters to machine each material. Helical milling performance was evaluated by the following indicators: tool life, cutting forces, hole quality(including diameter deviation, roundness, roughness, and hole edge quality). The results demonstrate that helical milling strategy Ⅱ outperformed strategy Ⅰ, leading to longer tool life(up to 48 holes), smaller cutting forces and better hole quality with higher geometric accuracy and smoother surface finish(Ra≤ 0.58 μm for Ti-6Al-4V and Ra ≤ 0.81 μm for CFRP), eliminating the need for reaming or de-burring.     

数控铣削加工刀具运动轨迹研究

数控加工刀具运动轨迹是确定数控加工工艺的重要环节.刀具运动轨迹设计质量的好坏,将直接影响零件的加工质量及加工成本.针对典型零件的铣削加工,以切削力波动小,表面质量精度高为优化目标对数控铣削加工的几种刀具运动轨迹进行优选.     

高速铣削过程中铣削力的建模

研究了球头铣刀高速铣削过程铣削力建模与仿真。考虑了作用在前、后刀面上的正压力和摩擦力,建立了高速铣削加工中局部铣削力模型,在上述基础上建立了整体铣削力的模型。通过铣削实验,验证了所建模型的正确性。     

球墨铸铁高速铣削加工工艺参数优化实验研究

针对难加工球墨铸铁材料进行高速铣削工艺参数优化研究,设计了四因素四水平正交实验,以获得铣削用量对加工过程力和表面粗糙度的影响关系,并利用多元回归分析建立铣削分力和粗糙度的经验模型。研究结果表明:每齿进给量对粗糙度值影响最为显著,铣削参数设置不同,产生的铣削分力不同,背吃刀量对铣削分力影响最大。针对最小铣削力与最小粗糙度的目标,分别得出最优的铣削用量参数。     

Optimization of Cutting Parameters in Helical Milling of Carbon Fiber Reinforced Polymer

To investigate cutting performance in the helical milling of carbon fiber reinforced polymer (CFRP), experiments were conducted with unidirectional laminates. The results show that the influence of cutting parameters is very significant in the helical milling process. The axial force increases with the increase of cutting speed, which is below 95 m/min; otherwise, the axial force decreases with the increase of cutting speed. The resultant force always increases when cutting speed increases; with the increase of tangential and axial feed rates, cutting forces increase gradually. In addition, damage rings can appear in certain regions of the entry edges; therefore, the relationship between machining performance (cutting forces and hole-making quality) and cutting parameters is established using the nonlinear fitting methodology. Thus, three cutting parameters in the helical milling of CFRP, under the steady state, are optimized based on the multi-objective genetic algorithm, including material removal rate and machining performance. Finally, experiments were carried out to prove the validity of optimized cutting parameters.     

A Web-based machining process monitoring system for E-manufacturing implementation

INTRODUCTION Recently, the application of the information technology into manufacturing fields gets more and more importance on the whole manufacturing shop floors. Currently, many researches reflect the effec- tiveness of knowledge-based production system re- lated to the exchange and management of various manufacturing information using information tech- nology via the Internet in order to increase the com- petitive power of industries. This research suggests a Web-based machining proce…     

差强度高精度尼龙工件的数控铣削加工

在装夹及加工差强度易变形尼龙类零件过程中,应该充分考虑零件材料特性。根据工件特点及其受力分析,采用合理的工装夹具、刀具及选用合理的刀具路径、切削用量,才能保证零件的加工精度,提高生产效率。     

基于ANSYS14.0的数控机床切削加工仿真及关键技术研究

建立了CK6140数控机床金属切削有限元数学模型,并利用有限元分析软件ANSYS14.0对其切削过程进行仿真,并且利用粘接区模型（CZM ）成功地解决了切削分离问题,对切削过程中的切削应力、切削温度、切削力进行了预测分析,通过自动测试系统进行实验验证预测数值与实际切削过程中数值的一致性,得出一些规律,为下一步数控机床的切削工艺优化及机床的智能化改造提供了一定的理论基础．     

Machining distortion prediction of aerospace monolithic components

To predict the distortion of aerospace monolithic components, a model is established to simulate the numerical control （NC） milling process using 3D finite element method （FEM）. In this model, the cutting layer is simplified firstly. Then, the models of cutting force and cutting temperature are established to gain the cutting loads, which are applied to the mesh model of the part. Finally, a prototype of machining simulation environment is developed to simulate the milling process of a spar. Key factors influencing the distortion, such as initial residual stress, cutting loads, fixture layout, cutting sequence, and tool path are considered all together. The total distortion of the spar is predicted and an experiment is conducted to validate the numerical results. It is found that the maximum discrepancy between the simulation results and experiment values is 19.0%.     

浅谈高速切削刀具系统的接口技术

作为先进制造技术，高速切削加工是机械制造业发展的必然趋势。它的应用将大幅度地提高加工效率和加工质量。高速切削刀具技术则是实现高速切削的关键技术之一。本文根据高速切削对刀具系统的要求，针对传统刀具系统在高速加工中存在的弊端，分析了适应高速切削加工的刀具系统的接口技术。     

薄壁类零件数控加工工艺改进分析研究

薄壁类零件在工业中的应用越来越多,保证其加工精度一直是工业生产中的难题。针对这一问题,分析了其加工精度的影响因素,对薄壁零件的装夹、切削参数、走刀路径与方式进行分析与优化,选择合理的工艺工序路线,完成了对薄壁零件的数控加工工艺的改进。     

基于光栅传感技术的测控系统设计

现在光栅作为精密测量的一种工具,在精密仪器、坐标测量、精确定位、高精度精密加工等领域得到了广泛应用,尤其被广泛应用在机器人生产线等设备中。文章介绍了由光栅位移传感器构成的全自动金属带锯床测控系统。全自动金属带锯床在单片机系统的控制下,完成被锯毛坯材料的输送、夹具的夹紧/放松、锯切长度的测量、定位和切断等工作。操作人员只要按要求输入所需材料的尺寸和根数,锯床就能自动完成预定的工作。由于使用了光栅式位移传感器,锯床的测量和定位总误差小于0.1mm。该系统以AT89C51单片机为核心,扩展了8279等其他逻辑芯片。为了增加系统的抗干扰能力,使其能在操作现场恶劣的电气环境下工作,该系统采用了光耦合器、电源净化等必要措施。     

基于高速切削的模具加工技术

采用高速切削技术加工模具,已经成为现代模具制造业的发展趋势,对模具加工工艺产生了巨大影响;为了达到理想的加工效果,基于高速切削的模具加工技术必须配置合理的高速切削机床、选用合理的切削刀具、采用优化的加工工艺及策略。     

往复走丝电火花线切割高效低损耗切割研究

电火花线切割加工是经两极间脉冲放电的电蚀现象来对各种形状以及轮廓的零件进行加工,注意此种加工方法并非依靠机械能来去除材料,而是依靠各种特殊能量形式（比如电化学能、电热能）来去除材料。实践表明,线切割加工既没有切削力,又能有效规避工件材料硬度的影响,因此被普遍用来进行各种材料的加工,往复走丝电火花线切割高效低损耗切割技术尤为重要。     

Performance evaluation of minimum quantity lubrication by vege- table oil in terms of cutting force, cutting zone temperature, tool wear, job dimension and surface finish in turning AISI-1060 steel

In all machining processes, tool wear is a natural phenomenon and it leads to tool failure. The growing demands for high productivity of machining need use of high cutting velocity and feed rate. Such machining inherently produces high cutting temperature, which not only reduces tool life but also impairs the product quality. Metal cutting fluid changes the performance of machining operations because of their lubrication, cooling and chip flushing functions, but the use of cutting fluid has become more problematic in terms of both employee health and environmental pollution. The minimization of cutting fluid also leads to economical benefits by way of saving lubricant costs and workpiece/tool/machine cleaning cycle time. The concept of minimum quantity lubrication （MQL） has been suggested since a decade ago as a means of addressing the issues of environmental intrusiveness and occupational hazards associated with the airborne cutting fluid particles on factory shop floors. This paper deals with experimental investigation on the role of MQL by vegetable oil on cutting temperature, tool wear, surface roughness and dimen- sional deviation in turning AISI-1060 steel at industrial speed-feed combinations by uncoated carbide insert. The encouraging results include significant reduction in tool wear rate, dimensional inaccuracy and surface roughness by MQL mainly through reduction in the cutting zone temperature and favorable change in the chip-tool and work-tool interaction.     

Mathematical Model and Simulation of Cutting Force in Plunge Milling Process

Plunge milling,also calledZ-axis milling,is one ofthe most effective machining methods in high speed metalremoval machining.Asfor curvedsurface of difficult-to-ma-chine material ,slot-cut working and machining withlongercutter of suspendinglength,the mach…     

Chip morphology predictions while machining hardened tool steel using finite element and smoothed particles hydrodynamics methods

Chip morphology predictions in metal cutting have always been challenging because of the complexity of the various multiphysical phenomena that occur across the tool-chip interface. An accurate prediction of chip morphology is a key factor in the assessment of a particular machining operation with regard to both tool performance and workpiece quality. Although finite element (FE) models are being developed over the last two decades, their capabilities in modeling correct material flow around the tool tip with shear localization are very limited. FE models with an arbitrary Lagrangian Eulerian (ALE) approach are able to simulate correct material flow around the tool tip. However, these models are unable to predict any shear localization based on material flow criteria. On the other hand, FE models with a Lagrangian formulation can simulate shear localization in the chip segments; they need to make use of a mesh-based chip separation criterion that significantly affects material flow around the tool tip. In this study a mesh-free method viz. smoothed particles hydrodynamics (SPH) is implemented to simulate shear localization in the chip while machining hardened steel. Unlike other SPH models developed by some researchers, this model is based on a renormalized formulation that can consider frictional stresses along the tool-chip interface giving a realistic chip shape and material flow. SPH models with different cutting parameters are compared with the traditional FE models and it has been found that the SPH models are good for predicting shear localized chips and do not need any geometric or mesh-based chip separation criteria.     

高速切削技术的发展应用与展望

高速切削加工是先进制造技术的重要组成部分之一。综述了高速切削的概述、优点、发展应用,同时也阐述了高速切削的技术要求,分析了高速切削机床、高速切削刀具。最后展望了高速切削的研究方向。     

Separate critical condition for ultrasonic vibration assisted grinding

Separate characteristic of the tangential ultrasonic vibration assisted grinding(TUAG)machining is analyzed based on TUAG process, and a critical speed formula is given to correctly set the machining parameters to insure the separate characteristics of TUAG process. The critical speed is not only related to the ultrasonic vibration amplitude and frequency, but also to the grinding wheel velocity and the cutting point space, and the grinding force can be decreased during the TUAG process with separability. Grinding force experiments are conducted, and the experimental results are in good agreement with the theoretical results.