6061铝合金微细刨削的表面粗糙度试验研究

试验研究了6061铝合金的微细刨削性能。在定制的精密雕铣床上,使用金刚石刀具在不同的切削条件下,对6061铝合金进行切削深度(0.005~0.1)mm的微细刨削,观察切削参数对工件表面粗糙度的影响。使用激光共聚焦显微镜对金刚石刀具以及各种切削条件下的加工表面进行分析。试验结果表明:切削速度和切削深度对铝合金工件刨削表面粗糙度影响很小,进给量是影响微细刨削铝合金表面粗糙度的主要原因。一般情况下,越小的进给量获得表面粗糙度值越小,但是进给量小到一定程度时,表面粗糙度趋于稳定。此时,工件表面的微裂痕,坑洞、划痕和材料本身的杂质是影响其表面粗糙度的主要因素。另外,单晶金刚石刀具的刃磨质量要优于聚晶金刚石刀具,因此可以获得更小的表面粗糙度值。结论表明,使用单晶金刚石刀具对6061铝合金进行切削速度v=2000mm/min、切削深度ap=10μm、进给量f=10μm的微细刨削可以获得Ra37.3nm的表面。     

超精密车削表面微观形貌的几何建模与仿真研究

在综合考虑刀具几何参数，刀具振动和最小切削厚度等因素对已加工表面形貌影响的前提下编写了表面微观形貌的仿真程序，在仿真时把一个随机振动信号成功地叠加在理论表面粗糙度中。提出一种建立圆弧刃金刚石车刀超精密车削表面粗糙度模型的新方法。结果表明，仿真得到的表面微观形貌，能够比较正确地反映出超精密加工将要获得的表面轮廓。     

微细铣削表面形貌形成分析

基于最小切削厚度的概念,提出了微细铣削过程槽底表面几何形貌仿真模型。通过微细铣削表面形貌的仿真和表面粗糙度Ra值的计算以及微细铣削实验,对微细铣削表面粗糙度随着每齿进给量变化的规律进行了分析和描述。     

车削加工工业纯钛(TA2)表面粗糙度研究

对工业纯钛(TA2)进行车削加工正交切削试验,分析切削用量和表面粗糙度的关系。极差分析表明:切削用量中进给量对表面粗糙度影响最大,其次是切削速度,切削深度影响最小;表面粗糙度随着进给量的增加呈线性增大,随切削深度的增加而逐渐增大;加工TA2过程中,随着切削速度的增加,表面粗糙度值整体呈减小的趋势。由于切屑形态的变化造成切削过程不平稳,引起刀具振动,导致表面粗糙度值产生波动。     

金刚石刀具高速精密切削加工的研究

采用聚晶金刚石刀具和天然金刚石刀具对LY12高强度铝合金进行了高速精密切削试验 ,系统研究了切削条件、切削用量对加工表面粗糙度的影响规律。结果表明 ,在比常用切削速度高 8倍的高速切削速度范围内(v=80 0～ 12 0 0m/min) ,采用圆弧刃天然金刚石刀具可获得Ra0 0 4～ 0 0 6 μm的高光洁加工表面 ;采用直线刃聚晶金刚石刀具可获得Ra0 0 7～ 0 1μm的光洁加工表面。切削速度对加工表面粗糙度的影响主要受到机床动态特性的制约 ;进给量的选择范围较大 ;背吃刀量对加工表面质量影响极大 ,为获得较小表面粗糙度必须合理选用背吃刀量     

金刚石涂层刀具铣削高硅铝合金的性能研究

选用未涂层、TiAlN涂层及金刚石涂层整体硬质合金两刃平头立铣刀,在相同切削参数下进行高硅铝合金的高速铣削加工试验。试验结果表明:金刚石涂层铣刀具有良好的耐磨性,在切削过程中刀刃磨损均匀缓慢,刀具使用寿命长,加工表面粗糙度值稳定性好,是铣削高硅铝合金的理想刀具。     

不同铣削参数对镁合金（AZ31B）表面质量的影响规律研究

进行了端面铣削加工对镁合金AZ21B表面特征的性能实验。在干式加工环境下,以刀具前角、线速度、最大切削厚度、切削深度为影响因子,以表面粗糙度作为分析表面完整性的指标,采用硬质合金刀具进行实验,实验结果表明：镁合金铣削加工中,随着切削深度、线速度、最大切削厚度的增加,工件的表面粗糙度也随之增加,其中切削深度小于6 mm、线速度小于1800 mm/s、最大切削厚度小于0.07 mm时,表面粗糙度值均为Ra1.0μm以下,可实现镁合金的高精度加工;同时刀具前角对镁合金加工至关重要,表面粗糙度随着刀具前角的增加呈现先增加、后降低的规律;当刀具前角在8°～16°区间内,表面粗糙度逐渐增加;当刀具前角为20°时,工件的表面质量相对较高,表面粗糙度为Ra0.5μm左右;结合整体试验的加工情况,特殊情况下刀具前角可以优先选择负角度加工。     

ZL109铝合金切削加工表面粗糙度演变研究

轻质高强ZL109铝合金应用广泛，切削加工过程中易形成积屑瘤，导致加工表面粗糙度不受控。对ZL109铝合金切削加工表面粗糙度演变进行研究，通过改变背吃刀量和进给量，进行ZL109铝合金棒材切削加工，分析表面粗糙度的演变规律，并分析切削温度、表面微观形貌、切屑形态、刀刃损伤对切削表面粗糙度的影响规律。研究结果表明，加工表面粗糙度值随背吃刀量和进给量的增大而增大，且背吃刀量对表面粗糙度的影响较大。当进给量为0.25～0.5 mm/r,背吃刀量为0.25 mm时，加工表面粗糙度值最小，表面完整性最好，并且刀刃损伤程度最轻。     

金刚石飞切加工微结构表面的表面粗糙度研究

为了获得具有纳米级表面质量的微结构表面,利用‘Nanosys-300’超精密复合加工系统实现了微结构表面的三维金刚石飞切加工,研究了主轴转速、进给量以及背吃刀量对微结构表面粗糙度的影响。通过对理论表面粗糙度分析可知：金刚石飞切加工微结构时理论表面粗糙度沿法线方向并没有变化,而沿进给方向存在着周期变化。减小进给量f和金刚石飞刀前端角ε或增大切削半径可以降低理论粗糙度值。实验分析结果表明：表面粗糙度值Ra随进给量的增加而增加,主轴转速对Ra影响不大。切削PC时,在5μm-40μm范围内,Ra随背吃刀量的增加而增加;而切削LY12时,在2μm-10μm范围内,Ra随背吃刀量的增加而减小。实验中Ra最好可达38nm（LY12）和43nm（PC）。最后利用优化工艺参数加工出了微沟槽阵列和微金字塔矩阵微结构。     

金刚石飞切加工微结构表面的工艺参数优化

为了获得具有纳米级表面质量的微结构表面,利用‘Nanosys-300'超精密复合加工系统实现了微结构表面的三维金刚石飞切加工,研究了主轴转速、进给量以及背吃刀量对微结构表面粗糙度的影响.理论分析表明,金刚石飞切加工微结构时理论表面粗糙度沿法线方向并没有变化,而沿进给方向存在着周期变化.减小进给量和金刚石飞刀前端角或增大切削半径可以降低理论粗糙度值.实验分析表明,表面粗糙度值Ra随进给量的增加而增加,主轴转速对Ra影响不大.切削聚碳酸酯(PC)时,在5～40 μm Ra随背吃刀量的增加而增加;而切削铝合金(LY12)时,在2～10 μm Ra随背吃刀量的增加而减小.实验中Ra最好可达38 nm(LY12)和43 nm(PC).最后,利用优化工艺参数加工出了微沟槽阵列和微金字塔矩阵微结构.     

Tool wear and its effect on surface roughness in diamond cutting of glass soda-lime

For the technology of diamond cutting of optical glass, the high tool wear rate is a main reason for hindering the practical application of this technology. Many researches on diamond tool wear in glass cutting rest on wear phenomenon describing simply without analyzing the genesis of wear phenomenon and interpreting the formation process of tool wear in mechanics. For in depth understanding of the tool wear and its effect on surface roughness in diamond cutting of glass, experiments of diamond turning with cutting distance increasing gradually are carried out on soda-lime glass. The wear morphology of rake face and flank face, the corresponding surface features of workpiece and the surface roughness, and the material compositions of flank wear area are detected. Experimental results indicate that the flank wear is predominant in diamond cutting glass and the flank wear land is characterized by micro-grooves, some smooth crater on the rake face is also seen. The surface roughness begins to increase rapidly, when the cutting mode changes from ductile to brittle for the aggravation of tool wear with the cutting distance over 150 m. The main mechanisms of inducing tool wear in diamond cutting of glass are diffusion, mechanical friction, thermo-chemical action and abrasive wear. The proposed research makes analysis and research from wear mechanism on the tool wear and its effect on surface roughness in diamond cutting of glass, and provides theoretical basis for minimizing the tool wear in diamond cutting brittle materials, such as optical glass.     

EFFECT OF CRYSTALLOGRAPHIC ORIENTATION ON CUTTING FORCES AND SURFACE FINISH IN DUCTILE CUTTING OF KDP CRYSTALS

In order to investigate the influence of material anisotropy in ductile cutting of Potassium Dihydrogen Phosphate (KDP) crystals, experiments of face cutting of (001) plane of KDP crystals are carried out by using an ultra-precision lathe with a single point diamond tool. The cutting forces, surface finish, and surface roughness in all crystallographic orientations of the machined surface are measured, and a power spectrum analysis method is used to reveal the cutting force patterns. The experimental results show that the cutting forces and surface roughness vary greatly with different crystallographic orientations of KDP crystal, and that amplitude variation of cutting forces and surface finish is closely related with the cutting parameter of the maximum undeformed chip thickness. With the maximum undeformed chip thickness below 30 nm, the amplitude variation of cutting force and surface finish is minimized, and a super-smooth surface with consistent surface finish in all the crystallographic orientations can be achieved. The surface roughness is 2.698 nm (Ra) measured by Atomic Force Microscope (AFM). These findings provide criteria for achieving a large-scale KDP crystal with consistent super-smooth surface using ductile cutting technology.     

CVD金刚石薄膜涂层刀具精密切削表面质量的研究

CVD金刚石薄膜刀具的表面粗糙度及加工过程中的切削用量是影响加工工件表面质量的关键因素。为改进CVD沉积工艺 ,减小金刚石薄膜表面粗糙度 ,提出了合理控制沉积气压的新工艺方法 ,并通过切削试验研究了不同沉积工艺下制备的CVD薄膜涂层刀具和加工过程中不同切削用量对精密切削表面质量的影响。     

硬质合金刀具基体沉积低表面粗糙度金刚石薄膜的工艺研究

CVD金刚石薄膜刀具的表面粗糙度是影响刀具切削性能的重要参数。为通过改进CVD沉积工艺减小金刚石薄膜表面粗糙度 ,提出了适当提高碳源浓度和合理控制沉积气压两项新的工艺方法 ,并通过切削试验研究了其对金刚石薄膜刀具耐用度及切削性能的影响     

固化紫外光胶粘剂切削性能研究

采用紫外光胶粘剂在芯轴表面固化后的精密切削技术,制备惯性约束聚变（ICF）研究中有机材料薄壁衬环。研究了紫外光粘接剂固化后不同剪切强度对加工衬环最小壁厚的影响规律,研究了主要切削参数对衬环最小壁厚和衬环外表面粗糙度的影响规律。研究结果表明,在3～10MPa的剪切强度范围内衬环最小壁厚能达到4～6μm。在主要切削参数中,进给量和背吃刀量对加工最小壁厚有较大影响。进给量对衬环表面粗糙度有一定的影响,而背吃刀量和主轴转速对衬环表面粗糙度的影响较小,固化紫外光粘接剂切削后的表面粗糙度接近Ra0．1μm。衬环内表面粗糙度取决于芯轴表面粗糙度,基本上是芯轴表面的复印。     

金刚石厚膜刀具切削性能的研究

制备了机夹式金刚石厚膜刀具 ,通过切削试验研究了金刚石厚膜刀具精密车削LY12铝合金时切削用量 (进给速度vf、切削速度v和切削深度ap)对切削表面粗糙度的影响     

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。     

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.     

Cutting performance of nano-crystalline diamond (NCD) coating in micro-milling of Ti6Al4V alloy

Hard coatings are an important factor affecting the cutting performance of tools. In particular, they directly affect tool life, cutting forces, surface quality and burr formation in the micro-milling process. In this study, the performance of nano-crystalline diamond (NCD) coated tools was evaluated by comparing it with TiN-coated, AlCrN-coated and uncoated carbide tools in micro-milling of Ti₆Al₄V alloy. A series of micro-milling tests was carried out to determine the effects of coating type and machining conditions on tool wear, cutting force, surface roughness and burr size. Flat end-mill tools with two flutes and a diameter of 0.5 mm were used in the micro-milling process. The minimum chip thickness depending on both the cutting force and the surface roughness were determined. The results showed that the minimum chip thickness is about 0.3 times that of the cutter corner radius for Ti₆Al₄V alloy and changes very little with coating type. It was observed from wear tests that the dominant wear mechanism was abrasion. Maximum wear occurred on NCD-coated and uncoated tools. In addition, maximum burr size was obtained in the cutting process with the uncoated tool.