三维断屑槽的断屑原理与设计

一、前言 在切削加工中,切屑的控制是一个极为重要的问题,直接影响切削加工的效率和质量。带状切屑不仅会损伤工件的已加工表面、打坏刀具、降低生产率和危及操作者安全,而且会造成停机误工。因此,断屑是急待解决的问题。由于断屑问题涉及工件材料、机床、刀具和切削用量等综合因素,虽有许多断屑方法,但适应20CrMnTi材料良好断屑的较佳方法,还是在刀具上采用三维断屑槽。     

断屑槽结构对Inconel 718镍基高温合金切削温度的影响研究

镍基高温合金强度高,在切削过程中产生的温度较高。基于ABAQUS有限元软件建立Inconel 718镍基高温合金三维切削仿真模型,通过单因素实验法研究断屑槽槽型结构对切屑形态与切削温度的影响。结果表明,不同断屑槽结构对切屑形态影响较大,并影响刀尖温度与最大切削温度。其中,梯形断屑槽与直弧形断屑槽相较于圆弧断屑槽与折线形断屑槽在断屑能力与切削温度等方面表现更优秀,这两种断屑槽刀具断屑及时,最大切削温度较低,切削温度变化较为平缓,更有利于提高工件表面质量和延长刀具使用寿命。     

聚晶金刚石刀具的断屑槽尺寸参数设计

为解决聚晶金刚石(PCD)刀具在铝合金材料切削过程中的切屑缠绕问题,在PCD刀具的前刀面上设计了断屑槽.通过对切屑受力过程和断屑槽断屑机理的分析、切削几何关系的推导和有限元切削仿真实验,提取了5个PCD刀具断屑槽参数,即棱带宽度、倾角、反屑角、槽宽和反屑面转角.建立了PCD刀具断屑槽棱带宽度和反屑角的计算公式;改进了槽...     

断屑槽槽型在控屑过程中对刀具振动的影响

通过ABAQUS有限元软件分别对梯形、直线圆弧型和梯形双槽结构断屑槽刀具切削Ti6Al4V钛合金材料进行三维切削仿真,并分析其切削力的波动,得到断屑槽槽型在控制切屑卷曲过程中对刀具在主运动方向、进给方向和切削深度方向振动的影响。经过仿真发现,梯形、直线圆弧型和梯形双槽结构断屑槽在控制切屑卷曲的过程中对刀具振动的影响各不相同。三种槽型结构中,梯形断屑槽刀具的振动最弱,直线圆弧型断屑槽刀具的振动最强。     

断屑槽槽背几何形状对车削钛合金的影响研究

为研究断屑槽槽背的几何形状对车削加工的影响,选用硬质合金和钛合金为研究对象,基于ABAQUS有限元软件建立三维切削仿真模型,通过单因素实验法研究了三种不同断屑槽槽背对切削力、切削热和切屑卷曲程度等的影响.结果表明:在实验参数的范围内,柱面型槽背刀具较单斜面型、斜面和柱面组合型槽背刀具的切削性能更好;柱面型槽背刀具切削所...     

刀具断屑槽参数对断屑影响的分析

断屑是机械加工中保证加工质量的关键一环,利用刀具断屑槽进行合理断屑是断屑过程中非常有效的一种手段。文中对断屑槽各参数对断屑的影响进行了细致的理论分析,为设计合理有效的断屑槽提供良好的理论依据。     

简易车削断屑装置及其断屑规律研究

通过在普通刀具体上添加断屑台的方法,设计并制造了可用于一般切削加工试验和精加工等切削力不大场合的断屑器.在此基础上通过试验探讨了断屑器的3个主要几何参数对断屑的影响.试验结果表明:断屑槽宽度对断屑能力影响最大,而断屑台角度对断屑能力的影响相对较弱,但角度的增加可以使得切屑更加顺利地排出.断屑台高度在一定范围内(0.5～4mm)对断屑的影响基本为零,低于0.5mm时,断屑能力逐渐下降.     

一种新的断屑方法及应用

研究断屑台对切削过程的影响。经试验，改变断屑台距刀刃的宽度并保证断屑台有足够的高度时，刀具与切屑的接触面积会发生变化，剪切角存在一个最大值，与之相对应的切削区变形最小。本文介绍了这种降低切削区变形的断屑方法及应用。     

两种新型断屑装置

在车加工时有两种主要断屑方法：在切削刀片上制作断屑槽和附加断屑器。第一种方法有许多缺点，因为断屑槽将降低切削刀片的强度，在切削时引起刀片振动，从而加速车刀的磨损，显著降低加工质量。此外，若切削用量和断屑槽的形状选择不当，则在刀片上会出现积屑瘤，从而降低耐磨涂层刀片的切削效果，急剧降低断屑的稳定性。下面介绍两种新型断屑装置，可有效断屑和提高加工质量。带回转断屑器的车刀图１所示为带回转断屑器的车刀。在刀夹１内的销钉２上装有切削刀片４和支承刀片３，以及可在销钉上回转的断屑器５，见图１（a）。断屑器是一…     

不锈钢车削刀片槽型断屑仿真研究

在DEFORM-3D平台上仿真研究了刀片槽型的前角、反屑角和棱带宽度等几何参数对刀具切屑形态的影响规律,适当增大切深和进给量有利于槽型断屑,采用较小的棱带宽度和较大的反屑角以及前角能够提高断屑效果。通过切削奥氏体不锈钢(1Cr18Ni9Ti)的试验验证了有限元仿真模型的有效性。     

FINITE ELEMENT ANALYSIS OF CHIP FORMATION IN GROOVED TOOL METAL CUTTING

Abstract

This paper presents the simulation of chip formation in grooved tool cutting using DYNA3D, 3D FEM software for dynamic nonlinear analysis that was used to simulate the orthogonal cutting problem. First, a flat-face cutting tool was employed in the simulation to verify the validity of the FEM model. Next, the same simulation techniques were used to study the effects of different groove geometries on the chip formation process in grooved tool cutting. In the first set of grooved tool simulations, the depth of the groove was constant while the width was decreased. In the second set, the width was constant and the depth was increased. By analyzing the chip flow, chip curl, chip thickness, stress and strain in the chip, the effects of different groove widths and depths on the chip formation process were then discussed.     

FINITE ELEMENT ANALYSIS OF CHIP FORMATION IN GROOVED TOOL METAL CUTTING

This paper presents the simulation of chip formation in grooved tool cutting using DYNA3D, 3D FEM software for dynamic nonlinear analysis that was used to simulate the orthogonal cutting problem. First, a flat-face cutting tool was employed in the simulation to verify the validity of the FEM model. Next, the same simulation techniques were used to study the effects of different groove geometries on the chip formation process in grooved tool cutting. In the first set of grooved tool simulations, the depth of the groove was constant while the width was decreased. In the second set, the width was constant and the depth was increased. By analyzing the chip flow, chip curl, chip thickness, stress and strain in the chip, the effects of different groove widths and depths on the chip formation process were then discussed.     

Efficient Chip Breaker Design by Predicting the Chip Breaking Performance

As machining technology develops toward the unmanned and automated system, the need for chip control is considered increasingly important, especially in continuous machining such as in the turning operation. In this study, a systematic chip breaking prediction method is proposed using a 3D cutting model with the equivalent parameter concept. To verify the model, four inserts with different chip breaker parameters were tested and their chip breaking areas were compared with those obtained from the model. Finally, a new type insert (MF1) for medium-finish operations with variable parameters was designed by modifying the commercial one. The chip breaking region predicted by using the modified 3D cutting model for the above insert agrees with the one obtained experimentally. The newly designed insert showed better chip breaking ability than the base model, and other performance tests such as surface roughness, cutting force and tool wear also showed good results.     

A knowledge-based approach for designing effective grooved chip breakers — 2D and 3D chip flow,chip curl and chip breaking

This paper presents details of a knowledge-based approach for designing effective grooved chip breakers for two- and three-dimensional chip flow, curl and breaking. The design criterion used in formulating this new approach is effective chip breaking at minimum power consumption. This work was aimed at achieving the optimum groove parameters and the best utilisation of groove profile under varying machining conditions. A systematic knowledge-pool was established from a series of well-designed machining experiments which form four knowledge databases (reference database, grooved chip breaker database, natural contact length database and 3D chip flow database). This paper shows how the chip breaker design parameters can be estimated for effective chip breaking at reduced power consumption. The basic tool design strategy presented in the paper also includes some guidelines, for cutting tool designers, highlighting the need for implementing a scientific approach for designing a chip breaker against the current practice of try and see methods.     

Orthogonal cutting of hardened AISI D2 steel with TiAlN-coated inserts—simulations and experiments

This paper presented a finite element simulation model for the analysis of AISI D2 steel turning with TiAlN-coated inserts. In this study, material constitutive model of hardened AISI D2 steel (HRC62) was built based on power law relationship, which was used in the FEM codes to describe the effect of strain, strain rate, and temperature on the material flow stress. A damage model was employed to predict the chip separation. Cutting edge radius and thickness of TiAlN coating were obtained by micro-optical system and SEM, respectively. The average friction coefficients were obtained by ball-on-disk friction test using UMT-2 high-speed tribometer. Numerical simulations of AISI D2 steel turning were performed using AdvantEdge? software. The simulated results of forces and chip morphology showed good agreement with the experimental results, which validated the precision of the process simulation method. The shear stress on the interface between coating and substrate of cutting tool was analyzed. And the maximal shear stress between coating and substrate was found on the cutting edge roundness near the flank face of cutting tool.     

基于Deform-3D准干式深孔BTA刀具钻削的仿真研究

采用Deform-3D有限元分析软件对准干式单刃内排屑BTA钻削做了仿真研究。应用Deform-3D软件设置模拟参数为干式钻削,在不同的切削用量情况下对切削力的大小、刀具磨损以及切削温度场进行了仿真分析,讨论了断屑判据以及分屑的形成过程,为准干式深孔加工的切削参数和刀具参数的进一步优化提供了依据。     

基于Deform 3D的高速车削加工仿真研究

基于有限元分析软件Deform 3D对高速车削加工进行仿真研究,通过实例分析了车削过程中切屑的形成过程,切削力大小、切削温度及应力应变的分布情况。该仿真结果对车削工艺效果的预测和优化具有现实的指导意义。     

基于FEM的三维切削力预报研究

采用大型有限元分析软件Deform3D建立了三维切削的切削力预报模型并对车削的切削力进行了预报。为了验证预报结果的准确性,进行了车削的测力实验,并将预报的结果、理论公式和传统的经验公式在相同切削条件下的计算结果与实验结果进行了对比分析。其结果表明采用有限元方法进行三维切削力的预报是可行的。     

FEM INVESTIGATION FOR ORTHOGONAL CUTTING PROCESS WITH GROOVED TOOLS-TECHNICAL COMMUNICATION

Rigid-visco-plastic finite element models are used to simulate the chip formation and cracking in the turning processes with grooved tools. The Johnson-Cook constitutive equation and Johnson-Cook damage model, which are appropriate for high-speed machining, are assumed for the workpiece material properties. Thermal effects in cutting are considered. The tool material is considered as rigid, but heat-conducting, with the properties of tool material H11. The calculated chip back-flow angle, curling radius and thickness are analyzed as three typical chip shape parameters. The effects of land length and second rake angle of the grooved tool on chip formation, cracking and temperature are discussed. Some simulation results are compared with other published analytical and experimental results.