高速铣削司太立合金切削力的研究

司太立合金是一种以钴、铬、钨为主要元素的硬质合金,较多用于以金属粉末的形式在各种基体金属表面进行堆焊,堆焊层具有耐高温、耐磨损、抗腐蚀等优点,但其切削加工性较差。通过建立司太立合金的高速铣削仿真模型,研究了铣削参数对铣削力的影响规律,建立了主切削力经验公式。结果表明,在研究参数范围内,铣削参数对主切削力的影响显著性由大到小的顺序为：每齿进给量、轴向切深、径向切深、切削速度,其中主切削力的变化与切削速度呈负相关,与每齿进给量、轴向切深和径向切深呈正相关。     

基于响应曲面法的45钢铣削力试验研究

为采用较小的铣削加工用量,探究对45钢的铣削力的影响规律,采用基于曲面响应曲面法设计试验,建立了45钢铣削力预测模型,运用方差分析法检验模型,并研究了交互作用对铣削力的影响。试验结果表明:每齿进给量f和轴向切深ap、每齿进给量f和径向切深ae的交互作用对铣削力Fx的影响较显著,建立的铣削力预测模型精确度较高,为实际的精细加工生产提供参考。     

考虑刀具偏心的变径向切深铣削稳定性研究

建立了变径向切深的铣削系统周期延迟微分模型,模型考虑了刀具偏心的影响,运用半离散估计技术获得了系统的稳定性.研究结果显示,随着径向切削深度的增大,稳定轴向切削深度先是急剧下降,在大约20%(径向切深与刀具直径的比值)径向切削深度后,稳定轴向切深基本不变.对于变径向切深加工,为了保证稳定加工,轴向切削深度应选取小于20%径向切削深度对应的稳定性极限值,最后通过试验验证了分析结果.     

不锈钢微结构铣削仿真与试验研究

针对不锈钢微结构微铣削过程中铣削力以及加工质量,进行了微铣削参数仿真及试验研究。通过单因素有限元仿真,揭示了微铣削关键工艺参数每齿进给量、轴向切深和径向切深对铣削力影响规律。结果显示,尺寸误差以及表面粗糙度随着径向切深的增加波动变化,总体数值变化不大,径向切深对不锈钢微结构微铣削过程中的加工质量影响不大。因此,实际生产中,可以采用大径向切深小进给,提高生产率并保证加工质量。     

高速铣削TB6钛合金切削力和表面粗糙度预测模型

进行涂层硬质合金刀具铣削高强度钛合金TB6试验,通过回归分析建立切削力和表面粗糙度的经验模型,研究切削速度、每齿进给量和切削深度等工艺参数对切削力和表面粗糙度的影响规律。研究表明,轴向切深对切削力的影响最大;工艺参数对加工表面粗糙度的影响程度依次为每齿进给量、轴向切深、切削速度和径向切深,切削速度和径向切深之间存在着显著的交互作用。     

薄壁零件高速铣削振动试验与分析

切削速会加强振动随针对薄壁零件在高速铣削加工过程中存在的振动问题,为有效抑制加工振动,采用单因素试验,对每齿进给量、度、工彳车径向轴向切深、径向切深等加工参数进行了研究。试验结果显示：每齿进给量并不是越小越好;转速过高过低都振动：切深增随轴向切深增大振动增强;随径向切深增大振动逐渐减弱,较大轴向切深下,径向切深小于1mm时,大而增强。综合数据优选：薄壁零件高速铣削时,每齿进给量在0．1～0．15mm之间;转速在11000—14000r／min之间;较小的轴向切深和较大径向切深会有效抑制加工振动。     

硬质合金平头铣刀铣削力系数的试验研究

为分析硬质合金平头铣刀的铣削力系数与各工艺参数的关系,选取不同每齿进给量、轴向切深、径向切深等工艺参数组合进行正交试验。采用二次回归方程方法拟合出切向铣削力系数函数和径向铣削力系数函数,并验证了铣削力系数函数的可靠性。通过试验研究,确认轴向切深和每齿进给量对硬质合金平头铣刀铣削力系数影响较大。     

钛合金TC21铣削切削力预测实验研究

基于正交试验,针对钛合金TC21难加工性,研究了铣削工艺参数切削速度、每齿进给、轴向切深和径向切深对切削力的影响规律;借助数理统计和回归分析实验理论和方法,建立了钛合金TC21切削力的预测模型,并对该模型及回归系数进行显著性检验。研究表明,在高速铣削TC21钛合金过程中,切削力随切削速度的增大而减小,随每齿进给、轴向切深、径向切深的增大而增大;切削深度、每齿进给量对切削力的影响较大,切削速度和径向切深对切削力的影响不显著;经切削验证,建立的切削力预测模型是高度显著的。     

航空不锈钢30CrMnSiA大去除率条件下的铣削力分析

针对航空不锈钢30CrMnSiA加工效率和加工质量的问题,从粗加工角度出发,研究大去除率条件下切削参数对切削力的影响规律。以主轴转速、每齿进给量、轴向切深与径向切深为影响因素,采用多因素正交试验与极差分析法对铣削力进行研究。分析结果表明:在大去除率铣削参数条件下,径向切深、每齿进给量、主轴转速分别为X、Y、Z三个方向切削力的最主要影响因素。     

微细铣削力对毛刺尺寸的影响规律研究

毛刺是影响微细铣削质量和效率的关键因素之一,本文运用有限元仿真与微细铣削试验相结合的方法研究了微细铣削中轴向力与径向力对毛刺宽度的影响,并以毛刺宽度为试验指标获得轴向力与径向力对毛刺宽度的影响规律。结果表明:当微细铣削参数大于临界未变形切屑厚度时,毛刺宽度随轴向切深、每齿进给量的增大而增大;当微细铣削参数小于临界未变形切屑厚度时,毛刺宽度随轴向切深、每齿进给量的增大先增大后减小,轴向力、径向力随轴向切深、每齿进给量的增大先增大后减小。总的来讲,毛刺宽度总体趋势随着轴向力、径向力的增大而增大,在后续的微细铣削参数优化中可以将切削力作为优化指标,间接地降低毛刺尺寸。     

Extension of process damping to milling with low radial immersion

This paper investigates the stabilizing effect of process damping at low cutting speeds for regenerative machine tool vibrations of milling processes. The process damping is induced by a velocity-dependent cutting force model, which takes into account that the actual cutting velocity is different from the nominal one during machine tool vibrations. The chip thickness and the cutting force are calculated according to the direction of the actual cutting velocity. This results in an additional damping term in the governing delay-differential equation, which is time-periodic for milling and inversely proportional to the cutting speed. In the literature, this term is often assumed to be constant and is considered to improve stability properties at low spindle speeds. In this paper, it is shown that the velocity-dependent cutting force model captures the improvement in the low-speed stability only for turning operations and milling with large radial immersion, while it results in a negative process damping term for low-immersion milling. Consequently, an extended process damping model is needed to explain the low-speed stability improvement for low radial immersion milling.     

An approach for analyzing and controlling residual stress generation during high-speed circular milling

In the rapid development of the modern high-speed milling industry, particularly in the aerospace field, machined residual stress is an important evaluation indicator of the quality, and whether it can be controlled or not is critical. In this article, experimental data of residual stress in feed direction and vertical feed direction validated with finite element (FE) simulation, which resulted in the finding that residual stress distribution is nonuniform in varied machined circular areas. The maximum residual tensile stress in different directions changes with coordinates. It is well known that uncut chip thickness (UCT) will influence the cutting force and temperature, but the relation between UCT and residual stress is still difficult to understand and explicate. Traditional measurement of residual stresses in the feed and vertical feed direction is difficult to explain. Based on the UCT model which is a function of feed rate and tool diameter, by measuring residual tangential and radial stress, it is observed that residual tangential stress is influenced by the UCT. Moreover, residual radial stress, under high feed rate, is distributed with wave change, and residual radial stress under smaller feed rate is still affected by the UCT. These results indicate that it is possible to optimize the residual stress distribution by controlling UCT (feed rate and tool diameter) with high-speed milling.     

高速铣削1Cr18Ni9不锈钢切削力建模及实验分析

采用多因素正交实验法,在五轴高速加工中心上,进行了高速铣削1Cr18Ni9不锈钢的实验。基于概率统计和回归分析原理,对回归方程进行了显著性检验,并建立了1Cr18Ni9不锈钢的切削力经验模型。通过分析正交实验直观图,研究了切削参数对切削力的影响。     

高速铣削P20模具钢复杂曲面粗糙度试验研究

应用硬质合金球头铣刀对P20（3Cr2Mo）模具钢进行了高速铣削精加工试验,研究了加工参数（包括主轴转速、每齿进给量和径向进给量）对曲面粗糙度的影响情况,分析了不同加工路径下粗糙度的形成机理。研究结果表明,高速条件下,主轴转速对加工表面粗糙度的影响不明显;每齿进给量和径向进给量对纵向和横向粗糙度的影响呈线性增加关系;为得到较小的粗糙度值,走刀路径应选择被加工曲面曲率半径变化大的方向为进给方向。     

A spline-based method for stability analysis of milling processes

Based on the idea of collocation methods, a spline-based integration method for the stability prediction of systems governed by time-periodic delay differential equations (DDEs) is presented. A B-spline curve is adopted to approximate the solution of the DDEs using the direct integration technique. The stability of the dynamic system is then predicted using the Floquet theory based on the established state transition matrix. The proposed method can apply to time-periodic DDEs where the delay and the period are incommensurate, and the proposed method is extended to study the stability of milling processes as well. For stability analysis of variable pitch cutters, the proposed method use one or multiple B-spline curves to approximate the solution of the DDEs according to the relationship between the cutter angles and the radial immersion, which can describe exactly the free vibration of the cutter. Compared with the numerical integration method and the Chebyshev collocation method, the simulation results demonstrate that the proposed technique is more efficient and accurate for stability prediction at low radial immersion cases in milling processes with variable pitch cutters.     

铣削颤振理论在钛合金结构件加工中的应用

针对钛合金结构件的弱刚度及难加工特性,提出了小径向铣削的方法。使用小径向铣削稳定预测理论,绘制出了稳定叶瓣图,最终选择了合理的加工参数,避免加工过程中发生的颤振,为该理论的实际应用提供了范例。     

摇臂铣快速进给箱的研制

本文论述的进给箱,采用齿轮集中变速并带快速传动,功率大、刚性足,有效改善了摇臂铣床的加工性能.     

基于铣削均匀性的切削参数优化

分析了高速铣削加工切屑形成过程中刀具—工件的接触行为,提出了考虑轴向切削深度和径向切削深度的铣削均匀性模型。在此基础上,以恒定的金属去除率为约束条件、铣削均匀性系数为优化目标,建立了切削参数的优化模型。通过对航空铝合金进行高速铣削试验,验证了铣削均匀性理论及优化模型的合理性。结果表明,对于航空铝合金的高速铣削加工,采用大径向切深—小轴向切深有利于提高铣削均匀性,减小切削力。