基于真实刀刃轨迹的立铣刀切削厚度模型

瞬时切削厚度是铣削加工建模研究的重要参数之一。通过分析刀刃切削轨迹,可以得到准确的瞬时切削厚度,但需要求解复杂的超越方程。通常对切削刀刃轨迹进行不同程度的简化来求解近似的瞬时切削厚度。为得到准确的瞬时切削厚度,提出一种新的切削厚度计算模型。基于立铣刀真实切削刀刃轨迹,对近似的切削厚度模型进行补偿,得到较传统计算方法更为准确的结果,计算过程也更为简单。通过切削力试验验证,该模型可以得到更好的动态切削力预测结果。     

考虑刀杆柔性的球头铣刀切削力模型的研究

建立了球头铣刀切削力模型，并基于刀具弹性变形模型及刀具避让的切屑厚度数学表达式，建立了切屑厚度与刀具变形量、刀具切削参数之间的数学关系，并提出了切削力收敛算法。最后，通过切削实验对切削力模型进行了验证。     

基于布尔运算的球头铣刀瞬时切削厚度建模及分析

在五轴球头铣刀的铣削加工中,瞬时切削厚度模型的建立是准确预测切削力的关键步骤之一。目前大部分模型注重刀具和工件接触区域的建模,仅考虑了参与切削的刀刃切削厚度,而忽略了刀刃对工件的影响。本文提出一种基于布尔运算理论的瞬时切削厚度建模方法,从瞬时切削厚度的理论出发,考虑了所有刀刃对工件切削厚度的影响,并引入根据球刃曲线创建的辅助实体模型对瞬时切削厚度进行提取,并经铣削力试验验证了该模型的有效性。     

径向跳动对球面铣刀切削力的影响研究

研究了径向跳动对刀齿的实际切削半径、切屑形状以及切屑厚度的影响机理。研究了各刀齿沿刀刃螺旋线的切削微元实际切削半径的数学表示和变化规律,实际切削半径的变化改变了刀齿的切削路径,使各刀齿上切屑形状分布不均匀。建立了三维切削下切屑厚度的数学表示,提出了递延累加切屑厚度计算算法。实验验证表明,计算的切削力与测量结果能很好地吻合,瞬时切削力、切削力峰值、平均切削力的预测精度达到85%以上。     

平头铣刀圆形铣削的切削力预测

针对平头铣刀的圆形铣削,提出一种适用于圆形铣削的切削力预测方法。建立铣刀与工件交点的数学模型,求解工件与铣刀的时变交点进而计算铣削过程中不断变化的切入角与切出角。同时分析了铣刀轨迹曲率效应对瞬时切削厚度的影响。通过槽铣试验来确定切削力系数。基于微分思想,将圆形铣削过程中的瞬时切削厚度运用到切削力模型中计算微元切削力,然后通过积分法获得切削力值。数值仿真与圆形铣削试验结果表明,预测的铣削力和试验结果在幅值和变化趋势上都吻合良好,从而验证了该切削力预测方法的有效性。     

基于DEFORM软件的刀具磨损对切削力与切削热的影响研究

基于DEFORM 2D/3D软件,通过硬质合金平头倒角立铣刀进行高速铣削AISI4340合金钢的仿真实验,在主轴转速1270r/min、进给速度104m/min、切削深度0.1mm的参数下,利用刀具的几何磨损模型和仿真模型模拟了不同刀具磨损类型对切削力与切削热的影响以及刀具二次磨损的主要位置。研究发现,刃口钝化对切削力的影响最大,其次为前后刀面磨损、后刀面磨损和前刀面磨损;后刀面磨损对切削热影响最大,其次为前后刀面磨损、刃口钝化和前刀面磨损。本研究促进了刀具的结构设计的发展和加工工艺的更优选择。     

圆弧刃刀具切削时理论粗糙度的计算

在圆弧刃刀具切削直线廓形时理论粗糙度计算的基础上，着重研究圆弧刃刀具切削圆弧廓形时理论粗糙度的计算方法。研究表明，工件已加工表面理论粗糙度取决于工件已加工表面的廓形、刀具切削刃形状和刀具切削运动方式，优化选取刀刃半径和刀具进给量后，可以有效地减小理论粗糙度值并提高切削效率。     

基于铣削力的微径球头铣刀切削机理分析

微小结构常采用介观尺度下微细铣削加工,而介观尺度切削机理有别于常规金属切削机理.本文使用微径二刃球头铣刀对310S不锈钢进行微细铣削加工,利用测力仪采集切削过程中的切削力数据信息.通过对切削力信息进行分析,研究微径球头铣刀进行微细铣削的机理.结果表明:微径球头铣刀进行微细铣削会产生刀具偏心、单齿切削和最小切削厚度现象....     

球头铣刀切削力模型的研究进展

综合评述了国内外对球头铣刀切削力模型的研究成果及发展动态,重点介绍了球头铣刀铣削力的经验系数建模、理论建模和自动化加工铣削力建模方法。     

Cutting Force Model for a Small-diameter Helical Milling Cutter

In the milling process, the major flank wear land area (two-dimensional measurement for the wear) of a small-diameter milling cutter, as wear standard, can reflect actual changes of the wear land of the cutter. By analyzing the wearing characteristics of the cutter, a cutting force model based on the major flank wear land area is established. Characteristic parameters such as pressure parameter and friction parameter are calculated by substituting tested data into their corresponding equations. The cutting force model for the helical milling cutter is validated by experiments. The computational and experimental results show that the cutting force model is almost consistent with the actual cutting conditions. Thus, the cutting force model established in the research can provide a theoretical foundation for monitoring the condition of a milling process that uses a small-diameter helical milling cutter.     

自由切削阶梯端铣刀铣削力试验研究

在传统阶梯端铣刀大平面铣削加工中,能采用较大的切削深度、进给速度和较高的铣削速度以提高铣削效率,但切削深度不能大于刀片边长的2/3,刀具耐用度和生产率较低。本文介绍了一种自由切削阶梯端铣刀的基本理论,每齿进给量和切削深度较大,能有效提高加工效率。通过铣削力试验,证明该自由切削阶梯端铣刀的铣削力比传统端铣刀低30%以上,刀具耐用度提高。     

一种螺旋刃球头铣刀的动态铣削力模型

针对高速铣削中广泛应用的螺旋刃球头铣刀建立刀具微元的铣削力模型,给出了瞬时切削厚度的计算方法,通过积分得出了一种新的整体铣削力模型。该模型考虑了动态铣削时刀杆振动对铣削力的影响,实验数据与仿真结果吻合较好,验证了该模型的正确性。     

正交试验在PCBN刀具铣削HT200的应用

应用正交试验法,研究PCBN刀具的铣削灰铸铁HT200时铣削用量对刀具耐用度的影响,建立了PCBN刀具耐用度和切削用量的刀具寿命公式,公式表明,切削速度是影响刀具寿命的最主要因素,进给量次之,背吃刀量影响最小。     

Dynamic Force Modelling for a Ball-End Milling Cutter Based on the Merchant Oblique Cutting Theory

A new dynamic force model for a ball-end milling cutter is presented in this paper. Based on the principle of the power remaining constant in cuts, the Merchant oblique cutting theory has been successfully used for the differential cutting edge segment of a ball-end milling cutter. A concise method for characterising the relationship of the complex geometry of a ball-end milling cutter and the milling process variables is determined, so that the force coefficients can be decomposed. The geometric property of a ball-end milling cutter and the dynamics of the milling process are integrated into the general model to eliminate the need for the experimental calibration of each cutter geometry and milling process variable. The milling experiments prove that this model can predict accurately the cutting forces in three Cartesian directions.     

A Cutting Force Model for a Waved-Edge End Milling Cutter

This paper presents a model for predicting the cutting forces for waved-edge milling cutters that are widely used in rough machining. The development of the model is based on the analysis of the complicated cutting edge of waved-edge cutter. According to the existing local cutting force model and from the relationship of local cutting force and chip load, local cutting force can be derived. Then the model is obtained by dividing the cutter into a number of differential elements in the axial direction and summarising the resultant cutting force produced by each differential cutter disc engaged in the cut. A numerical algorithm is introduced for the calculation of total force and the calibration of the relevant parameters in the model. A series of experiments under different cutting conditions are conducted to confirm the validity of the developed model. The agreement between the experimental and simulative results is satisfactory, which shows that the model is effective for cutting force prediction in end milling with waved-edge cutters. ID="A1"Correspondance and offprint requests to: Prof. L. Zheng, Institute of Manufacturing Engineering, Department of Precision Instruments and Mechanology, Tsinghua University, Beijing, 100084, P. R. China. E-mail: lzheng@tsinghua.edu.cn     

基于切削电流系数的铣刀磨损状态监测

基于切削力系数的铣刀磨损状态监测方法提出了与切削参数独立的刀具磨损指标。由于存在干扰机床正常加工、实时性不佳、传感器安装不便和成本过高等问题,限制了其在实际工业环境中的应用。针对上述问题,结合切削力与主轴电流的关系,提出一种基于主轴切削电流系数的铣刀磨损状态监测方法。首先,融合切削力系数和主轴电流的优点,建立铣削电流模型;其次,根据切削电流模型进行切削电流系数辨识,记录新刀状态下切削系数;然后,使用切削系数实时估计相同加工工况下新刀切削电流,监测实际切削电流偏离估计值的程度,判断铣刀磨损状态;最后,通过实验与力信号对比验证该方法的正确性。实验结果表明,该方法可以替代基于切削力系数的磨损状态监测方法,能有效、实时、无干扰、便利和低成本地识别新刀、正常和严重3种磨损状态。