SiC颗粒增强铝基复合材料高速铣削工艺研究

从颗粒增强金属基复合材料的应用和切削加工现状出发 ,针对SiC颗粒增强铝基复合材料的高速切削加工性能进行了试验分析。通过铣削试验 ,研究了铣削速度对铣削力、加工表面粗糙度、表面形貌以及刀具磨损的影响 ,分析了该材料的高速切削机理 ,并获得了能够保证对其进行高效高精度加工的合理工艺参数。     

基于正交实验的玻璃陶瓷铣削加工表面质量研究

采用正交试验法研究球头铣刀铣削加工牙科玻璃陶瓷时铣削参数对零件加工表面粗糙度的影响。设计了以铣削速度、每齿进给量、切削深度、径向切削宽度为主要因素的正交试验。通过极差分析方法研究了切削参数对表面粗糙度的影响规律,明确了主要影响因素。结果表明:各因素的影响程度从大到小依次为每齿进给量、径向切削宽度、铣削速度、切削深度。并建立了牙科玻璃陶瓷铣削加工表面的表面粗糙度预测模型。     

原位自生钛基复合材料最佳铣削温度区间的研究

为实现钛基复合材料的高效、低损伤铣削加工及降低该材料的铣削加工成本,对其最佳铣削温度区间进行研究。采用聚晶金刚石(PCD)刀具,研究切削温度对铣削该复合材料时的刀具寿命、刀具磨损和加工表面质量的影响规律。试验结果表明:PCD刀具的最佳铣削温度区间为500℃-600℃,考虑切削过程中刀具磨损对切削温度的影响,PCD刀具铣削钛基复合材料时的最佳初始切削温度区间为420℃-480℃;PCD刀具在最佳铣削温度区间切削时,刀具崩刃和磨粒磨损显著减轻,且适当提高切削速度并减小进给量可进一步延长刀具寿命;在高于最佳铣削温度下切削时,刀具扩散磨损剧烈,且加工表面变质层深度显著增大。研究得出以下结论:PCD刀具高速铣削钛基复合材料时存在最佳铣削温度区间和最佳初始切削温度区间,在最佳铣削温度下切削有利于增强相被刀具原位压入基体或随基体一起协同变形发生转动,从而明显减少加工表面的划痕、微坑洞、撕裂等缺陷。     

TC4钛合金微细铣削仿真与试验研究

钛合金由于其高的强度和耐热性、低的导热系数,在微细加工时若切削参数选择不合理容易导致切削力大、加工质量不稳定。在微细铣削加工中,由于刃口半径和尺寸效应的存在,选择合适的切削参数对于切削状态的改善有重要意义。通过仿真和试验对比分析,研究TC4钛合金在微细铣削过程中每齿进给量对切屑变形、铣削力和加工表面粗糙度的影响,以期为改善微细切削状态、提高加工表面质量提供合适的切削参数选择指导。结果表明,在使用刃口半径为2.05μm、刀具直径为1 mm的硬质合金铣刀对TC4钛合金进行微细铣削加工时,微细铣削TC4钛合金切削状态发生转变时所对应的临界每齿进给量为0.8μm/z;微细铣削时每齿进给量应大于此临界值。     

超低温微铣削芳纶纤维复合材料表面质量

在常温与液氮超低温环境下对芳纶纤维增强复合材料进行微铣削对比加工试验，获取不同参数环境下的加工表面质量和铣削力数据。结果表明：超低温铣削加工环境能够对加工材料进行改性，降低强度、韧性等属性，使其易于切削，减少抽丝拉毛缺陷的产生，纤维断屑彻底，有助于获得更加优异的表面形貌。超低温环境充分抑制了烧蚀缺陷的产生，提高了加工表面质量，铣削表面粗糙度可达到2 μm以下。与常温环境相比，超低温加工环境具有以下优势：在较高的进给速度下仍能保持良好的铣削表面质量，可以在保证加工质量的同时，一定程度上提高加工效率；铣削力减小明显，刀具表面磨损较小；改善了芳纶纤维复合材料的铣削加工性能，提高了铣削加工表面质量。     

球头铣刀高速铣削玻壳屏凸模表面粗糙度研究

通过用球头铣刀在屏凸模型面做切削试验,研究高速铣削时切削速度、进给量及其它因素对工件表面粗糙度的影响规律,获得了高速铣削屏凸模型面所需的优化切削参数,保证了表面加工精度,提高了加工效率。     

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。     

高速铣削SiC_p/Al复合材料表面形貌功率谱密度研究

为了研究切削参数对高速铣削SiCp/Al复合材料表面微观形貌的影响,本文采用不同切削参数进行了高速铣削实验,利用Talyscan150型表面粗糙度测试仪对加工表面进行测量,对获得的表面数据进行功率谱密度(PSD)分析。结果表明:高速铣削SiC颗粒增强铝基复合材料时,进给量与铣削深度对功率谱密度影响不大,切削速度是主要影响因素,并且随着切削速度的增大,功率谱密度值降低,表面质量提高。加工表面的主要空间波长成分能够反映加工工艺条件对加工表面形貌的影响。     

铝合金高速铣削中切削温度动态变化规律的试验研究

切削温度与刀具磨损、工件加工表面完整性及加工精度密切相关。高速切削过程中切削温度随工件材料、所选刀具及切削用量的不同而呈现出与普通切削过程不同的变化规律。本文应用红外热像仪测温系统对高速铣削过程中切削温度的动态变化规律进行试验研究 ,首次给出了铝合金高速铣削过程中存在的临界切削速度关键数据及切削温度随切削速度的变化规律 ,其结论有助于指导铝合金高速铣削加工、优化高速切削工艺及建立高速切削数据库。     

干式铣削对淬硬钢表面残余应力的影响研究

以SKD11淬硬钢为高速铣削研究对象,研究不同铣削参数对SKD11淬硬钢加工表面残余应力的影响.运用大型商业软件DEFORM-2D建立了干式铣削残余应力的有限元模型,并利用该模型分析不同切削参数对工件表面残余应力的影响情况及残余应力产生的原因;通过实验验证的方法将仿真的结果和实验结果进行对比得出模型误差小于16.4％,证明仿真模型可行.模拟实验得出:在高速铣削SKD11淬硬钢时,适当的减小切削速度和增大切削深度,可有效降低残余应力对加工表面质量的影响.     

硬脆颗粒增强铝基复合材料的已切削加工表面形貌及影响因素

为深入了解铝基复合材料的已加工表面形貌进行了切削实验研究。实验表明,因硬脆的增强颗粒阻碍基体塑性变形,铝基复合材料的已加工表面形成过程有许多特点,已加工表面中包含各种加工缺陷。经检测分析可知,增强颗粒的体积分数和颗粒大小是决定复合材料已加工表面形貌的主要因素,刀具材料、结构和切削参数也对此有重要影响。     

Effect of machining parameters on the milling process of 2.5D C/SiC ceramic matrix composites

Abstract

The C/SiC ceramic matrix composites are widely used for high-value components in the nuclear, aerospace and aircraft industries. The cutting mechanism of machining C/SiC ceramic matrix composites is one of the most challenging problems in composites application. Therefore, the effects of machining parameters on the machinability of milling 2.5D C/SiC ceramic matrix composites is are investigated in this article. The related milling experiments has been carried out based on the C/SiC ceramic matrix composites fixed in two different machining directions. For two different machining directions, the influences of spindle speed, feed rate and depth of cut on cutting forces and surface roughness are studied, and the chip formation mechanism is discussed further. It can be seen from the experiment results that the measured cutting forces of the machining direction B are greater than those of the in machining direction A under the same machining conditions. The machining parameters, which include spindle speed, feed rate, depth of cut and machining direction, have an important influence on the cutting force and surface roughness. This research provides an important guidance for improving the machining efficiency, controlling and optimizing the machined surface quality of C/SiC ceramic matrix composites in the milling process.     

TiAIN涂层铣刀铣削CoCrMo合金切削性能的试验研究

针对医用人工假体材料钴铬钼(CoCrMo)合金的高速铣削加工性能进行了试验研究。深入分析了铣削速度对铣削力、表面粗糙度、表面形貌和刀具的磨损的影响。并获得能够保证对其进行高效高精度加工的合理工艺参数。     

颗粒增强SiCp/Al复合材料的振动切削特性研究

通过实验对超声振动切削金属基复合材料的特性进行研究 ,为复合材料的高效加工提供理论依据。     

A study of ultrasonic vibration cutting of carbon fibre reinforced plastics

In the use of carbon fibre reinforced plastics (CFRP) it is often necessary to cut the components, but cutting CFRP is often made difficult by delamination of the composites and by the short tool life. In this paper, the machinability of CFRP by means of ultrasonic vibration cutting was experimentally investigated. The experimental results have led to a trial application of ultrasonic vibration cutting, which has been verified experimentally to be highly effective in view of cutting force and surface quality.     

基于车铣复合加工的已加工表面粗糙度分析

车铣复合加工是近些年来发展起来的先进的切削加工技术之一。本文采用正交实验方法,进行了正交车铣加工铝合金工件材料的切削实验,确定了车铣切削用量（铣刀转速、轴向进给量、每齿进给量等）与已加工表面粗糙度之间的关系。最后,通过正交实验法的方差分析进一步确定了各因素对表面粗糙度的影响及主次顺序。实验表明,铣刀转速（切削速度）和工件转速对表面粗糙度的影响较大。     

Application of Taguchi and response surface methodologies for surface roughness in machining glass fiber reinforced plastics by PCD tooling

This paper discusses the use of Taguchi and response surface methodologies for minimizing the surface roughness in machining glass fiber reinforced (GFRP) plastics with a polycrystalline diamond (PCD) tool. The experiments have been conducted using Taguchi’s experimental design technique. The cutting parameters used are cutting speed, feed and depth of cut. The effect of cutting parameters on surface roughness is evaluated and the optimum cutting condition for minimizing the surface roughness is determined. A second-order model has been established between the cutting parameters and surface roughness using response surface methodology. The experimental results reveal that the most significant machining parameter for surface roughness is feed followed by cutting speed. The predicted values and measured values are fairly close, which indicates that the developed model can be effectively used to predict the surface roughness in the machining of GFRP composites. The predicted values are confirmed by using validation experiments.     

基于淹没环境的超高压后混合磨料水射流切割试验研究

利用超高压水射流切割试验系统,在80～280MPa压力范围内进行淹没磨料水射流切割试验研究,通过试验及数据分析,验证了后混合淹没磨料射流切割的可行性,得出了磨料粒径和质量流量、射流压力、靶距、切割横移速度等参数对射流切割性能的影响规律,对于脆性和塑性材料,试验中各参数对切割深度的影响基本一致.结果表明:在试验给出的工况条件下,磨料流量存在最佳值,在一定范围内切割深度随磨料流量增加而增加,当磨料流量达到一定值后,切割深度随流量增加反而下降;切割深度与射流压力基本呈线性增长关系;随着靶距的增大,切割深度逐渐减小;切割深度随切割速度的增加呈指数衰减趋势,并且相同试验工况下淹没射流切割深度要大于非淹没状态.试验结果为超高压淹没磨料水射流的实际应用和研究提供了参考.     

Investigations into machining of composites

Fibre reinforced plastics (FRP) have an important place in the field of engineering materials. Initially, the main emphasis in research was on the development of materials. Currently, however, more attention is being paid to the industrial production of FRP products. Normally, conventional methods for machining of these materials are used, but reports have indicated poor performance of these conventional types of cutting tools during machining of FRP. In this paper, a new approach using electrochemical spark machining (ECSM) for cutting and drilling holes in composites is proposed.

The feasibility of using ECSM for machining FRP was first ascertained. Then a parametric study of the process was performed by planning the experiments using a ‘design of experiments’ concept as well as a ‘one variable at a time’ approach. Kevlar-fibre-epoxy and glass-fibre-epoxy composites as work materials, copper as the tool material and an aqueous solution of NaCl as electrolyte were used.

It is concluded that ECSM is a viable solution for cutting FRP. However, for achieving the desired accuracy, surface finish and economics of the process, the machining parameters need to be optimized.