金刚石磨头刀具磨铣加工对高体份SiCp/Al复合材料加工表面质量的影响

针对高体份SiCp／Al复合材料,采用佥刚石磨头刀具磨铣切削的加工方法,研究了高速磨铣加工中机床主轴转速、工件进给速度及背吃刀量对材料加工表面形貌损伤以及表面粗糙度的影响规律。研究表明,机床主轴转速的提高、工件进给速度的减小都能够减小材料表面形貌的损伤情况,改善加工表面粗糙度质量：背吃刀量的改变对材料表面形貌损伤以及表面粗糙度的影响不大。     

Surface roughness aspects in milling MDF (medium density fibreboard)

Medium density fibreboard (MDF) is an industrial wood product. It is made out of wood waste fibres glued together with resin by heat and pressure. Nowadays MDF products are preferred over solid wood in many applications due to certain comparative advantages. Milling is the machining operation frequently used in manufacturing parts of MDF. The aim of this article is to study the influence of cutting parameters (cutting speed and feed rate) on surface roughness in MDF milling. A plan of MDF milling experiments was performed with prefixed cutting parameters. The objective was to establish correlation between cutting speed and feed rate with the surface roughness in MDF panels after milling. The surface roughness decreases with an increase of spindle speed and increases with the feed rate. The milling tests showed the important role spindle speed plays on the evolution of the surface roughness as a function of material removal rate (MRR). The advantage of using a high cutting speed in MDF milling is evident.     

高速微铣削铝合金表面粗糙度的多指标正交试验研究

利用小型高速精密微铣削机床在6061铝合金表面加工微沟槽结构,对加工后的试件表面质量进行研究,以试件表面粗糙度Ra、Rz值为衡量指标,利用正交试验方法分析主轴转速、刀具悬伸量、进给量和轴向切深等因素对表面质量的影响。试验结果表明：试件表面粗糙度值整体变化趋势从大到小依次为中线区、顺铣区、逆铣区。主轴转速对表面粗糙度影响最显著,而其他因素随着表面质量要求的不同有所变化。综合考虑表面质量要求,最优组合为:刀具悬伸量为18mm,轴向切深为10μm,进给量为30mm/min,主轴转速为48 000r/min时,试件表面粗糙度最小,此时表面粗糙度Ra值为0.075μm,表面粗糙度Rz值为0.579μm。     

The effect of cutting parameters and cutting tools on machining performance of carbon graphite material

Abstract

The present study focuses on the effects of cutting speed, feed rate and cutting tool material on the machining performance of carbon graphite material. Polycrystalline Diamond (PCD) cutting tools are used in machining experiments and its performance is compared with the tungsten carbide (WC) and Cubic Boron Nitride (CBN) tools. Machining performance criteria such as flank and nose wear and resulting surface topography and roughness of machined parts were studied. This study illustrates that feed rate and cutting tool material play a dominant role in the progressive wear of the cutting tool. The highest feed rate and cutting speed profoundly reduce the tool wear progression. The surface roughness and topography of specimens are remarkably influenced from the tool wear. Major differences are found in the wear mechanisms of PCD and WC and CBN cutting tools.     

An experimental study of micromilling parameters to manufacture microchannels on a PMMA substrate

Rapidly prototyping a polymer microfluidic device is a growing interest in the application fields of the disease detection, drug synthesis, and the environmental monitoring because of the benefits of the miniaturized platforms. Micromilling is one of the micromachining methods and it has been commonly used to manufacture polymer microfluidic devices. The advantages of using micromilling for polymer microfluidic devices include faster fabrication process, lower cost, easier user interface, and being capable of fabricating complicated structures, which make micromilling a perfect candidate in rapid prototyping polymer microfluidic devices for research idea testing and validation. This aim of this study is to understand the influence of each micromilling parameter to the surface quality, followed by the factor analysis to determine the optimal cutting conditions. The parameters included spindle speed, feed rate, depth of cut, and the selection of coolant (compressed air/oil coolant), and the milled surface quality was measured by a stylus profilemeter. Polymethyl methacrylate (PMMA) is the mainstream substrate material in the microfluidics due to its excellent optical property and popularity and is used as the target substrate. The experiment results showed that using the compressed air as a coolant can deliver a better surface quality than the oil coolant, and the smallest roughness achieved was 0.13 μm with the spindle speed of 20,000 rpm, feed rate of 300 mm/min, and the depth of cut of 10 μm. Factor analysis revealed that the depth of cut has the largest impact while the spindle speed has the minimized impact to the surface quality of a micromilled PMMA substrate. To further confirm the optimal cutting conditions, another 12 reservoirs were micromilled with the optimal cutting conditions and the average roughness is 0.17 μm with a stand deviation of 0.08 μm.     

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.     

超硬微结构表面模具的精密磨削加工技术

针对超硬模具材料,研究磨削方式(顺磨和逆磨)、进给率和主轴转速等磨削参数对磨削后微结构表面的表面粗糙度和尖锐部分完整性的影响规律.基于磨削结果,对微结构表面质量不均一现象以及微结构表面磨削过程中的砂轮磨损分布进行研究.试验结果表明磨削后的微结构侧表面粗糙度小于底面粗糙度.采用逆磨可以获得更低的粗糙度和更加完整、锋利的尖锐部分.磨削后的表面粗糙度随着进给率的降低而减小,当进给率为0.2 mm·min-1时,微结构底面平均表面粗糙度Ra89 nm,侧面为Ra 60nm.磨削后,尖锐部分圆弧半径随进给率的降低呈现减小趋势,当进给率为0.5 mm·min-1时,其平均圆弧半径最小,为0.67 μm.主轴转速对表面粗糙度和尖锐部分圆弧半径的影响不大.由阶梯光栅表面结构性引起的,相对于其各个表面的磨削轨迹不相同,是导致磨削后阶梯光栅表面质量不均一现象主要原因.在微结构表面的磨削加工过程中,相对于砂轮的径向和轴向磨损,砂轮的形貌磨损更为严重.     

微铣金属表面微沟槽结构的粗糙度及形貌分析

为了提高和改善微沟槽表面质量,设计了高速微铣削实验,研究了微沟槽底面表面粗糙度和侧壁残留毛刺的变化规律。从理论角度引入了已加工表面的形成机理,建立了微观表面粗糙度理论模型,提出了刀具跳动对侧壁形貌变化影响的规律。利用三轴联动精密微细铣削机床加工微细直沟槽,并选取主轴转速、轴向切深、进给速度、刀具跳动量和材料组织结构为研究因素。采用多因素正交实验和极差分析法,对表面粗糙度值进行数值分析。铝合金,钢和钛合金三类微沟槽底面对应的最佳表面粗糙度值变化范围分别为1.073~1.481 μm,0.485~0.883 μm,0.235~0.267 μm;无刀具跳动钛合金微沟槽壁毛刺的最大高度为7.637 μm,而当刀具存在0.3 μm的径向综合跳动量时对应的微槽壁毛刺的最大高度为21.79 μm。铣削参数对表面粗糙度值的影响按从大到小依次为进给速度、主轴转速、轴向切深,且随着进给速度和轴向切深的增大,表面粗糙度值增大;随着主轴转速的增大,表面粗糙度值先减小后增大;在相同加工条件下,若微圆弧刀刃无磨损,微刀具的跳动量对微直沟槽侧壁表面质量有较大影响。同时,不同金属材料特性也是影响微沟槽表面质量的潜在因素。     

车用铝合金铣削参数优化及表面质量研究

LY12铝合金是一种常见的汽车轻量化材料,为了实现铝合金材料的高效高质量制造,以铣削过程中铣削用量的选取范围为约束条件,建立以材料去除率最高和表面粗糙度最低为目标的多目标优化模型。通过铣削加工正交试验,采用回归分析方法,建立表面粗糙度预测模型;利用多目标线性规划法求出多目标优化模型的最优解。最后通过分析铣削用量对表面质量的影响得出:在给定的铣削参数范围内,主轴转速和进给速度对表面粗糙度的影响最为显著,侧吃刀量次之,而背吃刀量影响最小。     

工程陶瓷主轴沟道表面磨削加工的实验研究

基于实验室自主设计研发的全陶瓷电主轴,利用曲线磨床对工程陶瓷主轴沟道进行磨削加工以及运用手工研磨的方法进行研磨。研究砂轮转速、工件转速、进给量、横向进给速度等磨削工艺参数对沟道表面粗糙度的影响,以及研磨工艺参数、磨料粒度、研磨时间、主轴转速对沟道表面轮廓度的影响。揭示了磨削参数与研磨参数对氧化锆陶瓷主轴沟道表面质量的影响,为硬脆材料高效的成型磨削加工提供参考依据。     

高体积分数SiCp/Al复合材料旋转超声铣磨加工的试验研究

由于大量高硬度增强相SiC颗粒的存在,高体积分数铝基碳化硅（SiCp/Al）复合材料的机械加工十分困难。旋转超声加工被认为是加工这种材料的有效方法。通过超声辅助划痕试验,分析高体积分数SiCp/Al复合材料旋转超声铣磨加工的材料去除机理。在超声振动的作用下,材料中铝基体发生塑性变形,其表面得到夯实;SiC增强相被锤击成细小的颗粒而发生脱落,形成较大的空洞。由于材料加工的缺陷大多产生于SiC颗粒的去除过程中,SiC颗粒的去除方式对加工表面的质量起着决定性的作用,选择合适的工艺参数可以有效提高加工表面质量。旋转超声加工工艺特征试验表明,超声振动可有效降低切削力;主轴转速对轴向切削力的影响最大,其次是进给速度,切削深度对轴向切削力的影响较小;另外主轴转速对表面质量的影响效果也最大,并随主轴转速的增大表面粗糙度增大。因此在加工过程中,可以适当加大切削深度,在保证加工质量的基础上,选择较大的进给速度,在保证刀具寿命的前提下,选择合适的主轴转速,以获得较优的加工表面质量和加工效率。     

铝合金高速切削表面粗糙度影响因素研究

为有效降低高速切削中铝合金的表面粗糙度值,通过多因素正交试验和单因素试验对各铣削参数进行研究,结果显示:各参数对铝合金表面粗糙度影响程度从大到小的顺序是:切削深度、主轴转速、每齿进给量、行距,且转速为18000r/min,每齿进给量为0.075mm,行距和每齿进给量一致,选择较小的切削深度时,在铝合金表面可获得较好的加工质量。     

基于响应曲面法的表面粗糙度预测模型研究

通过正交试验,研究了高速端铣加工中切削参数对表面粗糙度的影响。采用田口设计方法和响应曲面法构建了表面粗糙度预测模型,分析了主轴转速、进给量、切深对表面粗糙度的影响。结果显示,进给量对表面粗糙度的影响最显著,主轴转速次之,切深的影响不大。模型预测精度为99．84％,达到了较高的预测水平。     

EFFECT OF PROCESS PARAMETERS AND TOOL SHAPE ON THE MACHINABILITY OF A PARTICULATE FILLED-POLYMER COMPOSITE MATERIAL FOR RAPID TOOLING

This paper presents the results of an experimental study on the effects of machining parameters (cutting speed, feed, depth of cut) and tool shape on chip formation, surface topography, resultant cutting force and surface roughness produced in flat and ball end milling of the Ren Shape-Express 2000™ aluminum particulate filled-polymer composite material. This material is shown to exhibit a brittle-to-ductile transition in chip formation with decreasing cutting speed. The transition is explained by the strain-rate sensitivity of the polymer matrix and is found to correlate well with a corresponding change in the surface roughness. The absence of clear feed marks on the milled surface explains why molds made from the composite material require less hand polishing than machined metal molds. The influence of cutting conditions and tool shape (flat end vs. ball-nose) on the cutting force, surface roughness, and workpiece breakout are discussed and relevant comparisons with conventional metal and polymer machining are made.     

Experimental study on fabrication and evaluation of a micro-scale shaft grinding tool

This paper presents a micro-grinding experiment on AISI 1020 steel and Ti-6Al-4V to study micro-grinding principle and the change rule of the force and surface with different grinding parameters. A novel micro shaft grinding tool is fabricated by cold sprayed with CBN grains, the manufacturing is carried out on a desktop micro machine developed by NEU. Influences caused by particle size on surface quality has been discussed, it has been tested that low surface roughness could be achieved on 3000 particle size of micro shaft grinding tool, the roughness of AISI 1020 steel accomplished in the experiment is about 0.086 μm. Measured micro-grinding force of Ti-6Al-4V decreases with the increasing spindle speed and the decreasing cutting depth. The surface roughness decreases with the increasing spindle speed and the decreasing feed rate. The minimum surface roughness is 325 nm with the spindle speed of 48000 r/min and the feed rate of 20 μm/s.     

The use of D-optimal design for modeling and analyzing the vibration and surface roughness in the precision turning with a diamond cutting tool

Using a diamond cutting tool in the precision turning process, the vibration of tool-tip has an undesirable effect on the machined surface??s quality. The objective of this paper is to present the mathematical models for modeling and analyzing the vibration and surface roughness in the precision turning with a diamond cutting tool. Machining parameters including the spindle speed, feed rate and cutting depth were chosen as numerical factor, and the status of lubrication was regarded as the categorical factor. An experimental plan of a four-factor??s (three numerical plus one categorical) D-optimal design based on the response surface methodology was employed to carry out the experimental study. A micro-cutting test is conducted to visualize the effect of vibration of tool-tip on the performance of surface roughness. With the experimental values up to a 95% confidence interval, it is fairly well for the experimental results to present the mathematical models of the vibration and surface roughness. Results show that the spindle speed and the feed rate have the greatest influence on the longitudinal vibration amplitude, and the feed rate and the cutting depth play major roles for the transverse vibration amplitude. As the spindle speed increases, the overall vibration of tool-tip tends to more stable condition which leads to the results of the best machined surface. The effects of the feed rate and cutting depth provide the reinforcement on the overall vibration to cause the unstability of cutting process and exhibit the result of the worst machined surface.     

高速侧铣参数对7050-T7451铝合金表面粗糙度的影响

为提高航空结构件加工效率和表面质量,通过单一铣削参数实验,研究采用两种硬质合金刀具在高速铣削7050-T7451铝合金时,主轴转速、径向铣削深度、铣削进给速度等切削参数以及加工方式(顺铣、逆铣)对表面粗糙度的影响.分析表明:表面粗糙度随刀具尺寸和径向切深增大而增加,在铣削进给速度增加趋势下仅有较小波动,不受主轴转速直接...     

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。     

Experimental investigation and performance analysis of cemented carbide inserts of different geometries using Taguchi based grey relational analysis

In this work, effect of machining parameters cutting speed, feed rate and depth of cut, geometrical parameters cutting insert shape, relief angle and nose radius were investigated and optimized using Taguchi based grey relational analysis. 18 ISO designated uncoated cemented carbide inserts of different geometries were used to turn practically used automotive axles to study the influence of variation in carbide inserts geometry. Performance measures viz., flank wear, surface roughness and material removal rate (MRR) were optimized using grey relational grade, based on the experiments designed using Taguchi’s Design of Experiments (DoE). A weighted grey relational grade is calculated to minimize flank wear and surface roughness and to maximize MRR. Analysis of variance shows that cutting insert shape is the prominent parameter followed by feed rate and depth of cut that contributes towards output responses. An experiment conducted with identified optimum condition shows a lower flank wear and surface roughness with higher MRR. The confirmation results obtained are confirmed by calculating confidence interval, which lies within the width of the interval.     

高速铣削超高强度钢的切削力及表面粗糙度研究

选用涂层硬质合金刀具对300M超高强度钢进行高速铣削试验,通过单因素试验和多因素正交试验法,得出铣削参数(主轴转速、每齿进给量、铣削深度)对切削力及表面粗糙度的影响规律及主次关系。对正交试验结果做最小二乘法分析,建立切削力及表面粗糙度与铣削参数之间的经验模型;对经验模型的回归方程及系数做显著性检验,并对其进行参数优化,得出铣削参数的最优组合。结果表明:主轴转速和铣削深度对切削力的作用较大,而每齿进给量对其影响相对较弱;每齿进给量对表面粗糙度作用最强,铣削深度次之,主轴转速对其作用最弱。