缠绕式双卷筒提升机设计论文.doc

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缠绕式双卷筒提升机设计

59页 18000字数+说明书+外文翻译+开题报告+8张CAD图纸

A0总装图.dwg

A1主轴装配图.dwg

A1油缸.dwg

A1滚筒.dwg

A1盘式制动器.dwg

A2制动器筒体.dwg

A2离合器.dwg

A3制动器体.dwg

中期检查表.doc

外文翻译--ALSiC颗粒金属基复合材料的加工  中文版.doc

外文翻译--ALSiC颗粒金属基复合材料的加工  英文版.pdf

毕业实习报告.doc

缠绕式双卷筒提升机设计开题报告.doc

缠绕式双卷筒提升机设计论文.doc

摘 要

   单绳缠绕式矿井提升机的工作原理:钢丝绳的一端用钢丝绳夹持固定在卷筒幅板上,另一端经卷筒的缠绕后,通过井架天轮悬挂提升容器。这样,利用主轴旋转方式的不同,将钢丝绳缠绕上或放松,以完成提升或下降容器的工作。

   主轴装置是单绳缠绕式矿井提升机的主要工作机构,它的作用是: ①缠绕提升机钢丝绳;②承受各种正常载荷(包括固定载荷和工作载荷);③承受各种积极情况所造成的非常载荷。在非常载荷作用下,主轴装置部分不应有残余变形。单绳缠绕式矿井提升机的主轴装置是其核心部件,要求我们应认真设计,精心制造,这对于确保矿井提升机安全可靠运行,预防和杜绝故障及事故的发生,也具有十分重要的意义。

   本设计根据生产实际和预选的数据,以提升机的配套设备为核心,经过科学的计算和分析,设计、选择了一套矿井提升机的传动系统设备,并采用了光电测速传感器作为深度指示系统的数据采集装置,实现了从机械控制到数电控制的转变,同时为提升机控制系统的技术改造奠定了基础。

关键词:提升机,主轴,制动器,光电测速传感器

ABSTRACT

   What the principle of the single rope twines mine pit elevator is that: One end of the steel wire rope is fixed to Winding by the steel wire rope nip, another end after twined hangs and promotes the vessel by derrick wheel. In this way, we make use of the differences of the revolve way to twine or relax the steel wire rope so that to complete the vessel to step up or drop down.

   Main axle is the core part of the mine elevator. Its functions are: ① the steel wire rope of twines the type mine pit elevator ; ② endure a kind of normal load( including fixed load and work load ); ③ endure the kinds of unusual load which is result from positive situation. Under the unusual load function, the part of the main axle equipment should not remain remaining distortion. It required us to be careful designing and manufacture when designing and manufacturing. Only in this way, we can prevent the occurrence of failures or accidents .Obviously, the possesses is very significance.

   This design is on the basis of the data which are chosen by advance and actually, take the elevator supplementary equipment as the core, after the analysis and computation in science, has designed and chosen a set of the transmission system of the mine pits elevators, and used the electrical-light sensor as the equipment of the indicating system which to measure the amount of the depth of the tank. It enforced the change from the mechanically control to the numerical control, at the same time, has laid the foundation for improve the control system of the elevator.

   KEY WORDS: elevator, main axle, brake, electrical-light measurement velocity sensor

目  录

1  前 言1

1.1提升机的用途和发展概况1

1.2提升机的结构和用途2

2  课题设计简介5

2.1设计课题5

2.2设计步骤5

2.3设计思路5

3  JK—3提升机 (E系列)主轴装置的原始资料6

3.1本产品的型号、名称6

3.2本产品的性能指标和设计参数6

4  JK—3提升机(E系列)的选择和设计7

4.1 JK—3矿井提升机的工作原理和主要结构7

4.1.1主轴7

4.1.2卷筒7

4.1.3主轴承8

4.1.4盘形制动器装置9

4.1.5深度指示系统9

4.1.6减速器10

4.1.7联轴器10

4.2主轴装置的设计依据11

4.2.1钢丝绳11

4.2.2卷筒宽度11

4.2.3钢丝绳最大静张力11

4.2.4钢丝绳最大静张力差△F12

4.2.5最大提升速度Vmax12

4.2.6电动机功率PN12

4.3主轴的选择13

4.4主轴的设计13

5  主要通用部件的选型计算15

5.1盘形制动器15

5.2减速器15

5.3齿轮联轴器16

5.4弹性棒销联轴器16

6  主轴的校核17

6.1主轴强度校核17

6.1.1工况一:提升开始, 。18

6.1.2工况二:提升终了, ,。21

6.2主轴挠度校核26

6.2.1工况一:提升开始27

6.2.2工况二:提升终了27

7  轴承寿命计算29

7.1左轴承29

7.2右轴承30

8  螺栓联接的计算和校核31

8.1螺栓选用型号31

8.2高强度螺栓平面摩擦联接校核31

8.3受扭转力矩铰制孔螺栓强度计算31

9  机器的安装调试和维护33

9.1机器的安装要求33

9.1.1主轴装置33

9.1.2卷筒34

9.1.3盘形制动器34

9.1.4电动机34

9.1.5减速器35

9.2机器的调整35

9.2.1产品空运转试验要求35

9.2.2机器的负荷试车36

9.2.3机器的加载试车36

9.3机器的维护和保养37

9.3.1机器的维护和安全使用37

9.3.4制动器的保养37

9.4机器故障的排除38

结 论40

致 谢41

参考文献42

附录① 单绳缠绕式提升机设计规范(摘录)44

附录② 光电测速传感器52

2  课题设计简介

2.1设计课题

   我所设计的课题题目是:缠绕式双卷筒提升机,以提升机(系列)为例,主要是主轴装置的设计。

   提升机(系列)主轴装置设计的主要技术指标:

   1.卷筒直径;

   2.最大提升速度不大于;

   3.矿井深度设定为。

2.2设计步骤

   第一步:根据类似主轴结构选定主轴并进行优化设计;

   第二步:依据所设计的主轴选用通用部件;

   第三步:对主轴及通用部件进行校核计算;

   第四步:确定主轴装置的安装、使用和维护的方法。

本产品的性能指标和设计参数

   卷筒直径

   最大提升速度

   矿井深度

   容器自重

   载重量

2.3设计思路

   在总的设计过程当中,尽量选用通用部件,尽量采用成熟的结构和标准部件以及提升机通用部件,提高标准化、系列化、通用化的程度;积极、慎重地采用和推广新结构、新材料、新工艺,做到技术先进,结构、工艺经济合理;在结构上尽可能考虑最大限度地缩短安装调试时间,做到以最少的代价带来最大的经济效益;在设计过程中,我以可靠性、安全性、经济性、方便性为原则,认真、求实、虚心求教、改革创新为信念,完成每一项任务

   提升机是矿山大型固定设备之一,是联系井下与地面的主要运输工具,在矿山生产建设中起着重要的作用。矿井提升机主要用于煤矿、金属矿和非金属矿中提升煤炭、矿石和矸石、升降人员、下放材料、工具和设备。

   矿井提升机与压气、通风和排水设备组成矿井四大固定设备,是一套复杂的机械——电气排组。所以合理的选用矿井提升机具有很大的意义。

   矿井提升机的工作特点是在一定的距离内,以较高的速度往复运行。为保证提升工作高效率和安全可靠,矿井提升机应具有良好的控制设备和完善的保护装置。矿井提升机在工作中一旦发生机械和电器故障,就会严重地影响到矿井的生产,甚至造成人身伤亡。

   熟悉矿井提升机的性能、结构和动作原理,提高安装质量,合理使用设备,加强设备维护,对于确保提升工作高效率和安全可靠,防止和杜绝故障及事故的发生,具有重大意义。

   矿井提升机已有很长的发展历史。早在八百多年以前,我国古代劳动人民就发明了轱辘,用手摇骨碌从地下提升煤炭和矿石,以后发展成畜力绞车。十九世纪,由于电力的发展,电力拖动的提升机逐渐代替蒸汽提升机。近几十年来,矿井提升机有了更大的发展,出现了多绳摩擦式提升机以及先进的拖动和控制系统。目前,国外的矿井提升机正向体积小、重量轻和自动化的方向发展,以适应深井和大量的需要。

   解放以前,我国根本不能制造大型矿井提升机。解放以后,我国建立了矿井提升机的制造工厂,并已由仿制和改进国外产品发展到能自行设计和制造。目前,我国已能成批生产近代化的大型矿井提升机。

   1958年,我国设计并试制成功第一台DJ2*4多绳摩擦式提升机,为我国矿井提升机的制造和使用开辟了一个新的领域。目前,我国已能成批生产JKM型多绳摩擦式提升机,并正在逐渐形成多绳摩擦式提升机的新系列。

1.2提升机的结构和用途

   每台提升机都由若干部分组成:主轴、缠绕机构、轴承和主制动器。这些便是基本部分。缠绕机构有好几种,最常用的结构是单圆柱形滚筒及双圆柱形滚筒。对于单圆柱形滚筒,两根钢丝绳功用一个滚筒缠绕面;第一根钢丝绳自滚筒松开而相应地漏出的滚筒面由另一根钢丝绳缠上。对于双圆柱形滚筒,没根钢丝绳都缠绕在特有的滚筒上,即在任何时刻钢丝绳都只是缠在两支滚筒总缠绕面的一半上。在这种情形下,一个滚筒结实地固定在主轴上,另一个则活套在主轴上,借助于离合器与主轴相连,以便在必须时可使二滚筒作相对转动。滚筒相对转动的可能行使得提升设备的操作变得容易,因为可以容易地调节由于钢丝绳弹性变形而逐渐伸长的长度。此外,还可以补偿由于对钢丝绳做周期性的试验而截下的长度。依次,在每个滚筒的表面除了等于提升高度的钢丝绳长度外尚需附加30米长的钢丝绳,这样才有可能当滚筒作相对转动以使一根钢丝绳的铅垂长度增加时并不使另一根钢丝绳缩短。当有双滚筒提升机时还可能更换操作水平。当上容器停在井口车场时而下容器移至新的位置。这在一个提升水平但有个承受台时也是需要的,例如翻转式罐笼当提升重物及提人时容器的终端位置是不同的。当用单滚筒或滚筒的离合器不作用时,除原定水平外,如要服务于另一水平或承受台则仅能用一个提升容器;第二个容器不过起着平衡锤的作用,此时,提升生产率骤然减少一半。

   提升机的第二个重要部分为把电动机的转动传到安置有缠绕机构的主轴上的减速器。减速器结构因其类型、用途不同而异。但无论何种类型的减速器,其基本结构都是由轴系部件、箱体及附件三大部分组成。轴系部件包括传动件、轴和轴承组合,轴承组合包括轴承、轴承盖、密封装置以及调整垫片等。减速器箱体上用以支持和固定轴系零件,保证传动件的啮合精度、良好润滑及密封的重要零件。箱体质量约占减速器总质量的50/%。因此,在箱体结构对减速器的工作性能、加工工艺、材料消耗、质量及成本等有很大影响,设计时必须全面考虑。为了使减速器具备较完善的性能,如注油、排油、通气、吊运、检查油面高度、检查传动件啮合情况、保证加工精度和装拆方便等,在减速器箱体上常需设置某些装置或零件,将这些装置和零件及箱体上相应的局部结构统称为减速器附属装置或简称为附件。它们包括:视孔与视孔盖、通气器、游标、放游螺塞、定位销、启盖螺钉、吊运装置、油杯等。

   制动器为提升机设备第三个重要部分。制动器直接作用于制动轮或制动盘上产生制动力矩的部分按结构分为盘式和块式闸等;第四部分是传动机构,是控制并调节制动力矩的部分。按传动能源分为油压、压气或弹簧等;第五部分为深度指示器及与其相连的控制保护装置,其用途为给司机指出提升容器在井筒中的位置;第六部分为操作台,电动机及制动器的操纵手把均匀集中在这里,有时也有离合器操纵手把;提升机最后一部分为油压及压气设备前者为每一机器所必备的;并且在油压制动传动时,它需作为机器润滑,同时也作为制动装置。当用压气制动时,油压设备所起的作用仅限于机器的润滑,而此时需要附加压气设备,而在油压制动时却不需要附加压气设备。

   这次毕业设计过程的认真思考、反思,我总结出此次设计过程的得与失:

   1.面对主轴装置的设计,我开始设计自己的方案,由于没有经验,走了很多弯路。经过指导老师的提醒,我才认识到研究以往设计资料的重要性,然后根据相似结构设计主轴,最终取得了成功。

   2.在接下来的设计过程中,我吸取了开始的教训,按照《矿井提升机械》上的要求进行设计和选型,然后对其进行校核,确定其是否满足裁量的强度刚度要求和设计任务书的要求,不满足要求,再重新设计主轴进行校核,直到设计出合适的主轴为止。

   3.主轴与固定卷筒支轮的连接采用无键连接,因为我们选择的主轴的安装方式为热装,这样比键连接更安全;卷筒的安装方式为对半结构,这样一方面便于安装,另一方面运输方便;卷筒与固定支轮的连接采用高强度螺栓连接,装拆方便。这些都是在借鉴以往设计成果的基础上决定的方案。

   4.其次,在设计中没有考虑到整个装置的润滑,比如轴承的润滑、制动器的润滑;液压站也没有涉及,这是本设计的一个缺憾。

   5.在设计中,我在深度指示系统上使用光电测速传感器接收、传递信号,使提升机的整体结构更加紧凑,占地面积大大减少,同时提高了可编程控制器的使用价值,优化了提升机电控系统的结构和功能。

   通过这次设计,我认识到一名设计人员在设计过程中要具有求实、严谨、负责的态度,要有积极创新的精神,这是我在这次毕业设计中的所感和所得。

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内容简介:
河南理工大学万方科技学院本科毕业设计(论文)中期检查表指导教师:向道辉 职称:教授所在院(系):机械与动力工程系 教研室(研究室):机械制造教研室题 目缠绕式双卷筒提升机学生姓名孙建坤专业班级07机制(2)班学号0720150117一、 选题质量:1, 该选题为缠绕式双卷筒提升机的设计,这可以对我大学四年所学知识进行一次较为全面的练习。2,题目的难易程度适中,并且是多个行业常用设备,是我们熟悉的课题。 2, 题目的工作量:要求完成3张以上的A0图纸,2.53万的说明书一份。4,所选题目紧密结合着生产实际,在我的专业范围之内,这必对我以后从事的生产和实践工作有很大的帮助。 二、 开题报告完成情况:结合现在的新技术和新设备等方面资料的搜集,通过对可行性的分析,我认真的进行了这次毕业设计的选题。选此题目以后,针对这个设计的题目我认真的查阅了相关的资料,最后结合所有的材料和设计任务完成开题报告。三、阶段性成果:1通过对缠绕式双卷筒提升机的整体了解,在加上指导老师的仔细讲解,我对本次毕业设计的课题有了较为深入的理解,现在我已收集了大量的资料和文献,为设计的顺利完成做好了充分的准备。2. 在老师的指导和同学的帮助下找到了设计的基本方法,开始了一些基本的结构设计。3. 正在进行装配图的CAD画图。四、存在主要问题:这次是我第一次系统的进行设计,所以在刚开始时有些茫然不知如何着手,设计工作做的很不顺利,后来找了指导老师,老师对此进行了仔细的讲解,并与本组同学进行了商量,我逐渐找到是设计的切入点,我觉得这对我以后设计工作的顺利进行有很大的帮助。随着设计的逐渐进行我又遇到了许多的新的更加复杂的问题,这些问题使我充分认识到了自己在以前学习中的不足和差距,所以我要以本次设计为契机加强自己薄弱环节的学习,争取使我的毕业设计能够取得好的成绩,也使我所学的知识能够在以后的工作中发挥更大的作用。五、指导教师对学生在毕业实习中,劳动、学习纪律及毕业设计(论文)进展等方面的评语指导教师: (签名) 年 月 日3AL/SiC颗粒金属基复合材料的加工摘要尽管金属基复合材料颗粒具有优越的机械性能和热性能,但是有限的切削性却一直使金属部件的替代受到很大的威慑。在加工过程中,增强硬磨料的相时会导致加工工具的快速磨损,因此,会产生较高的加工费用。一系列高速转动测试只为选择最佳刀具材料,刀具几何形状和切削参数来车削含有20%的SiC/AL金属基复合材料。结果表明,多晶金刚石工具(PCD)与氧化铝和涂层硬质合金工具相比,可以提供给用户满意的刀具寿命。其中在金属基复合材料的加工下研究过程中,后面一种材料的工具更容易受到过度的边缘碎屑和月牙洼磨损。此外,PCD刀具的成本可通过在干切削进给量f=0.45mm,切割速度V=894 m/s与切削深度为1.5毫米时被鉴别。与这些切削参数类似, 在刀具上形成相对较小的累积起来边缘,会很好的保护它免受进一步边缘上工具的磨损和磨损。具有零度前角和较大刀具半径的多晶硅刀具大多被用于粗加工。关键词:金属基复合材料,刀具磨损1 简介 一组新形式的金属基复合材料(MMCs)已受到大量的研究,因为在20世纪80年代早期的试验工程材料中,最流行的材料为硅,碳化硅,氧化铝,铝,钛,磁性地层,其中钛和镁合金是常用的基体相。大多数金属复合材料密度约为三分之一。在钢铁行业,由于这些潜在高强度和刚度吸引力再加上在高温无法工作的性能,导致金属基复合材料竞争非常严峻。在航空航天和汽车应用中,高温合金,陶瓷,塑料被重新设计的钢件。后者中的材料,操作方法比以往任何时候都不可能有太多的进步,今后仍然不可避免。 有人对金属基复合材料微粒(PMMCs)特别感兴趣,不只是因为他们表现出较高的延性和金属基复合材料向异性。此外,PMMs提供了卓越的耐磨性。虽然许多工程元件制成PMMCs是由形状近乎成形和精进的铸造工艺,但是他们需要这些系列,其中荷兰国际集团达到了预期的尺寸和表面光洁度。PMMCs加工提出了重大挑战,因为加固材料的数量明显比常用高速钢(HSS)和硬质合金工具更难。因此,钢筋相磨具磨损快的原因,普遍是因为使用的PMMCs,其明显阻碍其加工性和高加工成本。文献综述从现有文献上很明显看出PMMCs的性能,密度(克立方厘米) 2.77热导率(卡尔厘米秒K在22C 0.47比热(卡尔克k) 100 0.218 200 0.239 300 0.259平均热膨胀系数 50100 17.5 50300 21.1 50500 21.4极限强度 () 262屈服强度() 21.4伸长率() 1.9弹性模量(GPA) 98.6洛氏硬度(B) 671.5表1典型的 F3S.20S物理性能特性的形态,分布和数量的增强相分数,以及矩阵的性质,都是影响因素,整体切割工艺相对较少,但尚未涉及到工程的生产力的工艺优化。例如,莫纳亨研究在加入25碳化硅和铝硬质合金刀具的磨损机理。PMMC在速度低于20米每分钟时的加工速度开发了一种工具寿命的关系,为硬质合金刀具加工过程中碳化硅和铝PMMCs在速度低于每分钟100米时。然而,文献的作者建议的内置式边现象,是在观察期间碳化硅加工进一步研究铝PMMCs。Reillyet等排名刀具磨损方面的各种刀具材料,然而,他们的切削用量不超过每分钟125米和f=1.0mm,这是取得使用立方氮化硼工具。类似测试结果报告了布伦等在有关刀具的磨损率,主要是由于磨损涉及到刀具的硬度。 Winery归因于碳化物耐磨工具,打磨表面上形成氧化铝颗粒擦在芯片的流动方向的工具。不过,拉伸颗粒也有可能导致同样的效果,碳化硅颗粒硬度大于WC。托马茨认为少于氧化铝和碳化硅的硬度涂层提供碳化硅加工过程中几乎没有任何优势:铝PMMCs。布伦提出使用较低的切削速度,减少切削温度,从而加速扩散和粘着磨损和热削弱工具。由于铝的工具面和晶界自扣押的地点,作者建议使用硬质合金工具与大的晶粒尺寸。 一些研究者表明,多晶金刚石(PCD)的工具是唯一的工具伴侣-里亚尔,它是提供一个有用的工具,能够生活在铝PMMCs在的加工。 PCD是难比Al2O3和和不产生化学反应倾向与工件材料。托马茨比较了化学气相沉积法(CVD)插入到锡,钛(CN)和氧化铝涂层刀具的性能。化学气相沉积工具提供更好的整体比其他工具的性能。 Lane 研究了不同的心血管疾病的工具,薄,厚的薄膜的性能。根据他们的观察,化学气相沉积薄膜的工具与失败在这20碳化硅端铣灾难性的铝PMMC。这个工具的失败是由于涂层剥落和由此产生的损坏年龄相对软硬质合金衬底。此外,具有较好的晶粒尺寸25毫米PCD刀具磨损微承受比为10毫米晶粒尺寸切割工具的磨损。在聚晶金刚石晶粒尺寸进一步增加不利于刀具寿命,而导致在表面光洁度显着恶化。 表三 刀具材料对切削力和温度影响 (r=1.6mm; =0)刀具材料 测量切削力 (N) 测量切削温度 (C)PCD (v=894 m min-; 97.00 440F=0.45 mm rev-;doc=2.5 mm)PCD (v=670 m min-; 98.10 410f=0.25 mm rev-;Doc=1.5 mm)Al2O3(v=248 m min-; 183.85 520 f=0.2 mm rev-; Doc=0.5 mm) TiN (6248 m min-; 143.52 500f=0.2 mm rev-; Doc=0.5 mm这是因为晶粒尺寸的PCD材料的刀具在25毫米很容易退出了边缘。相对于切削参数对刀具寿命等影响减少了。主要归因于对PCD刀具的磨损(由磨损)在防皱到在所获得的动能增加碳化硅颗粒磨。另一方面,布伦等由于在刀具磨损中的热降解增加刀具材料。刀具磨损被认为与车削材料成反比。托马茨等把刀具寿命归因于在更高的进给量增加了复合材料的热软化。作者认为,工件材料变得柔软和颗粒成为压入工件,造成工具本身磨损少。然而,莫林认为由于以更大的进给量减少对刀具前沿的磨损,磨料碳化硅颗粒减少接触。尽管在解释背后的不同进给量工具磨损机理的争论,所有的研究人员建议使用切割进给速度和进给量是在粗加工尽可能咄咄逼人。最后,关于冷却液的应用,在美国科学家建议以便对于可能采取的保护优势建成边缘现象。 总之,进行文献回顾显示,更积极的(速度,进给量和切削深度)切削参数的影响还需要进一步重新搜索,以改善切削过程的经济性。此外,一些重要参数进行了前人所忽略,其中有刀具几何形状和冷却剂的应用。2 试验材料和切割工具2.1工件材料 该加工利用Duralcan进行了调查 F3S.20S铝:碳化硅金属基复合材料。有一对颗粒平均直径为12毫米。表1显示了对A356- 20的PMMC的物理力学性能一些。在此之前进行切割实验,测试材料是完全热处理对T71条件。测试材料是在对一百七十七点八毫米直径305毫米的长度形式。2.2 切削工具 各种刀具材料(涂层硬质合金,氧化铝)和几何结构,在Oblique对于转向就业进行了测试和不同的切削参数,每个工具伴侣-里亚尔就业。然而,对于比较刀具磨损的目的,所有的切削试验共进行了拆除金属固定量(300立方毫米)。表2总结了刀具数据在干车削试验,进行了10种惠普标准的现代化数控车床。切削力康具磨损测量康廷每个切削参数组合。该工具的力量测定采用一奇石三分量测力计和切削条件选择精心为每个工具材料。一些在切削实验中,测量采用K型工具到被粘热电偶刀具离前沿1毫米时的温度。测量的技术可靠性检查,不断重复的实验和各组的结果表明,如果在他们展出了不到5的变异。在每个切削试验结束时,刀具磨损进行了检查用扫描电子显微范围和X射线分散技术。该工具后刀面磨损(VB)的测定用工具显微镜。 3 结果与讨论3.1 刀具材料的影响 一个初步的测试并进行一系列对刀具磨损的影响刀具材料,切削部分和切削温度在粗糙投票荷兰国际集团20的碳化硅和铝PMMC。图1可以看出,氧化铝TiC的工具遭受的EDGE芯片形式的过度磨损水平。氧化铝颗粒的研磨拔出工件颗粒,其中有一个更大的硬内斯号(VHN间接),比氧化铝颗粒(VHN在Al2O3TiC 2500公斤力每平方毫米; VHN在碳化硅3000公斤力每平方毫米)。月牙磨损也观察到,这是由于该是由磨损造成的沟槽扩大。由于严重的边缘切削,Al2O3TiC切削力的工具明显比实验更高氮化钛(见表3)涂层刀具。氮化钛涂层规定对磨料的影响,一些保障SiC颗粒。聚优越的性能金刚石工具,相比,无论氧化铝:TiC的和TiN涂层硬质合金工具,是由于他们的高耐磨性和高导热性,这导致了更低的切削温度,如图表3。因此,所有的可加工性进行的研究其后关注到的最优化PCD刀具切削过程中使用。3.2 切削参数的影响图2和3表明,随着切削速度对切屑的增加,减少切削力深度。这可能是归因于热软化工件材料。另一个可能的原因是由于引入到刀具几何形状的变化后,形成建成的边缘。图4(b)给出了透视内置的注册材料色散图所示4(a)条。图6(a)内置式边对PCD工具(v= 670 m/min,f=0.35mm/rev,doc=1.5mm,r=1.6毫米,=0),图 (b)相当于 6(a)项,只是doc= 2.5mm图7(a)SEM照片说明上的PCD刀具前刀面磨损溶解后用氢氧化钠积屑瘤(v=670 mmin-1,f=0.15mm,doc= 1.5mm,=1.6mm,a=0。C)图 8切割对刀具NK细胞的磨损(PCD刀具速度:r=1.6毫米,a=0。C;广角点:V=670 m.min-1,doc=1.5mm,;轮点:v=894 m.min-1,doc=1.5mm)。图9影响对工具NK细胞的磨损(PCD刀具切削深度:=1.6mm,a=;v=894 m ;方点:doc=1.5mm轮点:doc=2.5mm)。建成边缘,观察到的所有工具在所有切削条件。这是因为颗粒碳化硅:铝金属基复合材料有材料的特性所有(即应变硬化两相材料在高温和压力)。在高切削速度(图5(b),一个较小的积屑瘤形成,比积屑瘤形成(图5(a)的积屑瘤的高度测量前刀面垂直)在对比度,通过增加从1.5到2.4毫米的切削深度,大积屑瘤形成(图6(a,b)项,这可能中断造成的工具和由此产生的切削工具对工件表面粗糙度和不利影响尺寸精度。该工具的拓扑图显示,主要磨损PCD的机制是磨损(如凹槽表现平行于芯片水流方向)。这些沟槽可以归因于三个因素。第一,氧化铝是形成于边缘的工具,这是很难足以开槽的金刚石生产磨损。第二为国家的PCD槽为铝扣押和拉出来的金刚石颗粒的过程中,如图所示7(甲,乙)。第三个可能的原因背后的PCD槽是sic颗粒研磨的工具。因此,PCD刀具与金刚石颗粒比碳化硅晶粒尺寸较大粒子可以更好地抵御磨损和密CRO的切割的碳化硅颗粒。然而,我们应请注意,由于增加的PCD颗粒的大小,PCD刀具的断裂特性恶化,因在材料中的一个缺陷增加。认为是对的工具面形成凹槽充满了工件材料。这秉承层有些保护,以防止进一步的工具的前刀面磨损。尽管如此,该工具后刀面继续受到磨损。因此,后刀面磨损(VB)的是作为刀具寿命准则与V=0.18毫米。图8显示,随着切削速度的增加,后刀面磨损增加。这可能是由于增加在研磨粒子的动能,正如先前推测的巷17。切深增加导致在增加后刀面磨损(图9)。这是由于增强微磨损,在切削刀具后刀面。这在一个更深入的情况下切点,该工具后刀面较大的表面面积接触磨损。进给速度提高了有益的影响。随着在图所示。 8和9的进给速度的增加,该刀具磨损减少。在高进给量情况下,固定体积的金属切削,刀具表面会有较少的磨料PMMC接触。另一个优势获得了通过提高进给速度为改变芯片的形式。在低进给率,该芯片形成了连续的,也被困难和灾害的处理。在高进给速度和高深度切(f=0.35mm,doc= 2.0mm),形成了芯片不连续的。尽管在所有的实验PCD刀具具有高进给量较低,导致工具磨损,对最佳切削明确的决定参数应考虑的影响表面上的完整性和切削参数亚表面损伤产生的工件,分析表面完整性和芯片形态将在第二部分介绍本研究性学习。 10 a-b-c 图 11 a-b图10(a)对PCD刀具前角的刀具NK细胞的磨损(v=894m/min,doc=2.5mm,r=1.6mm;a=0。C;)(b)对PCD刀具前角对的切削力(v= 894 m/min,doc=2.5mm)(c)扫描电镜图像说明由腐蚀PCD刀具磨损。图11(a)SEM图,说明了PCD刀具磨损的切削(v= 894 m/min,doc=1.5mm,v=0.35mm_1,r=0.8mm,a=0。C)(b)影响刀尖半径对工具铿俛NK细胞的磨损(v= 894mm/min,doc=2.5mm,a=0。C;工具:方点,r=1.6mm;轮间距点,r=0.8mm)。3.3 刀具几何形状的影响在刀具前角对的深远影响PCD刀具的磨损。三种不同的角度进行靶检查。正如从10(a)图中可以看出工具类倾斜角度出发,进行积极的和负面的靶角工具。为增加负前角后刀面磨损情况下可能的原因,是更大的切削力遇到这样的前角(图10(b)项)。此外,该芯片生产成为捕获之间的工具和工件,造成损害该工具的表面。正前角与工具显示不规则的后刀面磨损和过度的切割点蚀边缘地带,如图所示。 10(c)项。刀尖半径在决定了关键作用该工具的磨损模式。由于刀尖半径从1.6至0.8毫米,该工具被发现遭受过度切削和月牙磨损,作为如图所示。 11(a)条。这导致了切削工具在切削力和后刀面磨损增加,如图11(b)项。半径小工具因此建议的在穷为轻切削精加工业务使用参数。小鼻子半径也将以产生更好的几何精度。4 结论(1)的主要工具是磨损,磨损机理微切削刀具材料晶粒,表现为在刀具面平行沟槽到芯片流方向。所有的工具都进行测试也因后刀面损,由于磨损。没有证据化学磨损(例如,通过扩散)。(2)PCD刀具磨损持续最少的COM削减到TiN涂层硬质合金刀具和氧化铝:TiC的工具。这无疑是由于金刚石的硬度优和耐磨性,以及低摩擦系数,加上高导热。这导致PCD刀具时,降低了切削温度就业。另一方面,锡涂层硬质合金工具和Al2O3/TiC的工具遭受过度火山口边缘的磨损和剥落。(3)对PCD的前刀面形成的沟槽涂抹工具,充满了工件材料。这内置式形式是有利的,因为它保护刀具前进一步磨损。(4)在确定切削参数发挥了关键作用,采矿刀具后刀面磨损量,以及大小建成的边缘。工具磨损降至最低提高进给速度,这导致了减少接触的工具和SiC颗粒打磨。虽然提高铝切割速度,预计到加速度,中心提供全方位的侧面磨耗显着,其结果表示,最小的磨损增加。高等教育切割速度均与在增加切削温度,而导致形成一个保护坚持一层薄薄的工件材料上该工具。这种保护建成边缘形式无法在规模增长的摩擦增加的速度。切削参数范围内的测试范围,在894 m最小速度,f= 0.45毫米和切削深度d=1.5毫米的结果是最小的工具磨损。这些切削参数提高用PCD刀具时。(5)PCD刀具半径与鼻子16毫米和仰角a=0 也导致了较低的后刀面磨损。致谢笔者要感谢来自美国Duralcan的R.Bruski和来自GE超硬材料D.Dyer,他们提供了试验材料,切割工具和整个研究项目的有益意见。在实验进行加工智能机械及制造麦克马斯特大学的研究中心。(1)的主要工具是磨损,磨损机理微切削刀具材料晶粒,表现为在工具面平行沟槽到芯片流方向。所有的工具都进行测试也因后刀面磨损,由于磨损。没有证据化学磨损(例如,通过扩散)。(2)PCD刀具磨损持续最少的COM削减到TiN涂层硬质合金刀具和氧化铝:TiC的工具。这无疑是由于金刚石的硬度优和耐磨性,以及低摩擦系数,加上高导热。这导致PCD刀具时,降低了切削温度就业。另一方面,锡涂层硬质合金工具和Al2O3/TiC的工具遭受过度火山口边缘的磨损和剥落。(3)对PCD的前刀面形成的沟槽涂抹工具,充满了工件材料。这内置式边形式是有利的,因为它保护刀具前进一步磨损。(4)在确定切削参数发挥了关键作用,开采的工具NK细胞的磨损量,以及大小建成的边缘。工具磨损降至最低提高进给速度,这导致了减少接触的工具和SiC颗粒打磨。铝虽然提高切割速度,预计到加速度,中心提供全方位的NK细胞磨料磨损厉害,结果表示,最小的磨损增加。高等教育切割速度均与在增加切削温度,而导致形成伸出工件材料薄层上该工具。这种建成边形式无法在规模增长的摩擦增加的速度。切削参数范围内的测试范围,在1894 m最小速度,女0.45毫米转1和切削深度1.5毫米,导致在最小的工具磨损。这些切削参数提高PCD刀具的利用率。(5)PCD刀具半径16毫米的仰角0度也导致了较低NK细胞的磨损。Journal of Materials Processing Technology 83 (1998) 151158Machining of Al/SiC particulate metal-matrix compositesPart I: Tool performanceM. El-Gallaba, M. Skladb,*aPratt and Whitney Canada, Mississauga, Ontario, L5T1J3, CanadabDepartment of Mechanical Engineering, McMaster Uni6ersity, Hamilton, Ontario, L8S4L7, CanadaReceived 20 March 1997AbstractDespite the superior mechanical and thermal properties of particulate metal-matrix composites, their poor machinability hasbeen the main deterrent to their substitution for metal parts. The hard abrasive reinforcement phase causes rapid tool wear duringmachining and, consequently, high machining costs. A series of dry high-speed turning tests were performed to select the optimumtool material, tool geometry and cutting parameters for the turning of 20%SiC/Al metal-matrix composites. The results indicatethat polycrystalline diamond tools (PCD) provide satisfactory tool life compared to alumina and coated-carbide tools, where thelatter tools suffered from excessive edge chipping and crater wear during the machining of the metal-matrix composite understudy. Furthermore, the cost of PCD tools could be justified by using dry cutting at feed rates as high as 0.45 mm rev1, cuttingspeeds of 894 m min1and a depth of cut of 1.5 mm. With these cutting parameters, the relatively small built-up edge formedon the tool protects it from further wear by abrasion and micro-cutting. Polycrystalline tools with zero rake angle and large toolnose radii are recommended for the roughing operations. 1998 Elsevier Science S.A. All rights reserved.Keywords:Metal-matrix composites; Tool wear1. IntroductionMetal-matrix composites (MMCs) form one group ofthe new engineered materials that have received consid-erable research since the trials by Toyota in the early1980s 1. The most popular reinforcements are siliconcarbide and alumina. Aluminium, titanium and magne-sium alloys are commonly used as the matrix phase.The density of most MMCs is approximately one thirdthat of steel, resulting in high specific strength andstiffness 2. Due to these potentially attractive proper-ties coupled with the inability to operate at high tem-peratures, MMCs compete with super-alloys, ceramics,plastics and re-designed steel parts in several aerospaceand automotive applications. The latter materials, how-ever, may not have much further capacity for theinevitable future increases in service loads 3.Particulate metal-matrix composites (PMMCs) are ofparticular interest, since they exhibit higher ductilityand lower anisotropy than fiber reinforced MMCs 2.Moreover, PMMCs offer superior wear resistance 3.WhilemanyengineeringcomponentsmadefromPMMCs are produced by the near net shape formingand casting processes, they frequently require machin-ing to achieve the desired dimensions and surface finish.The machining of PMMCs presents a significant chal-lenge, since a number of reinforcement materials aresignificantly harder than the commonly used high-speedsteel (HSS) and carbide tools 4. The reinforcementphase causes rapid abrasive tool wear and therefore thewidespread usage of PMMCs is significantly impededby their poor machinability and high machining costs.2. Literature reviewFrom the available literature on PMMCs, it is clear* Corresponding author. Fax: +1 905 5727944; e-mail: mech-macmcmaster.ca0924-0136/98/$19.00 1998 Elsevier Science S.A. All rights reserved.PIIS0924-0136(98)00054-5M. El-Gallab, M. Sklad/Journal of Materials Processing Technology83 (1998) 151158152Table 1Typical physical properties of Duralcan F3S.20S 20PropertyDensity (g cm3)2.77Thermal conductivity (cal cm1s1K1) at 22C0.47Specific heat (cal g1K)0.218100C0.239200C0.259300CAverage coefficient of thermal expansion17.550100C50300C21.121.450500CUltimate strength (MPa)262Yield strength (MPa)21.41.9Elongation (%)98.6Elastic modulus (GPa)6791.5Rockwell hardness (B)Table 2Tool geometryToolGeometryPCD (tipped-80rhomboid)Rake angle, a: 5, 0, 5Clearance angle: 7Approach angle: 5Tool nose radius (mm), r: 0.8, 1.6TiN coated carbideRake angle, a: 0(triangular)Clearance angle: 7Approach angle: 5Tool nose radius (mm), r: 1.6Rake angle, a: 0Al2O3/TiC ceramic(triangular)Clearance angle: 7Approach angle: 5Tool nose radius (mm), r: 1.6crystalline diamond (PCD) tools are the only tool mate-rial that is capable of providing a useful tool life duringthe machining of SiC/Al PMMCs. PCD is harder thanAl2O3and SiC and does not have a chemical tendencyto react with the workpiece material. Tomac et al. 5compared the performance of chemical vapor deposi-tion (CVD) inserts to that of TiN, Ti(CN) and Al2O3coated tools. CVD tools offered better overall perfor-mance than that of the other tools. Lane et al. 18studied the performance of different CVD tools withthin and thick films. According to their observations,CVD tools with thin films failed catastrophically duringthe end milling of 20%SiC/Al PMMC. This tool failurewas attributed to coating spalling and consequent dam-age to the relatively soft carbide substrate. Further-more, PCD tools with a grain size of 25 mm betterwithstand abrasion wear by micro-cutting than toolswith a grain size of 10 mm 8,14. Further increases inPCD grain size do not benefit the tool life, but rathercause significant deterioration in the surface finish. Thisthat the morphology, distribution and volume fractionof the reinforcement phase, as well as the matrix prop-erties, are all factors that affect the overall cuttingprocess 2,4, but as yet relatively few works related tothe optimization of the productivity process have beenpulished. For example, Monaghan 2 studied the wearmechanism of carbide tools during the machining of25% SiC/Al PMMC at speeds below 20 m min1.Tomac et al. 5 developed a tool life relationship forcarbide tools during the machining of SiC/Al PMMCsat speeds lower than 100 m min1. However, theauthors of Ref. 5 recommended further research onthe built-up edge phenomenon that is observed in alltools during the machining of SiC/Al PMMCs. OReillyet al. 6 ranked various tool materials with respect totool wear, however, their cutting parameters did notexceed 125 m min1and 1.0 mm depth of cut, whichwas achieved using cubic boron nitride tools. Similartest results were reported by Brun et al. 7 who relatedthe tool wear rate, mainly due to abrasion, to the toolhardness. Winert 8 attributed the wear of the carbidetools to abrading Al2O3particles that form on thesurface and rub the tool in the direction of the chipflow. However, pulled SiC particles could also lead tothe same effect, SiC particles also being harder than theWC. Tomac et al. 5 suggested that coatings with lesshardness than that of Al2O3and SiC offer little to noadvantage during the machining of SiC/Al PMMCs,Brun et al. 7 suggested using lower cutting speeds toreduce the cutting temperature, which accelerate diffu-sion and adhesion wear and thermally weaken the tool.Since aluminium tends to seize on the tool face andsince grain boundaries are the sites of seizure, theauthors recommended using cemented carbide toolswith a large grain size.Several researchers 725 have indicated that poly-Fig. 1. SEM figure showing wear on Al2O3tool (6=488 m min1,f=0.2 mm rev1, doc=0.5 mm, r=1.6 mm, a=0).M. El-Gallab, M. Sklad/Journal of Materials Processing Technology83 (1998) 151158153Table 3Effect of tool material on cutting forces and temperatures (r=1.6mm; a=0)Measured cut-Tool materialMeasured cuttingtemperature (C)ting force (N)PCD (6=894 m min1;97.00440f=0.45 mm rev1;doc=2.5 mm)98.10PCD (6=670 m min1;410f=0.25 mm rev1;doc=1.5 mm)520Al2O3(6=248 m min1;183.85f=0.2 mm rev1;doc=0.5 mm)143.52500TiN (6=248 m min1;f=0.2 mm rev1;doc=0.5 mm)Fig. 3. Effect of depth of cut on the cutting forces (PCD tool: r=1.6mm, a=0; square points: 6=894 m min1, doc=1.5 mm; roundpoints: 6=894 m min1, doc=2.5 mm).of cut that are as aggressive as possible during theroughing operations. Finally, with regard to the coolantapplication, researchers at Duralcan USA 1123, rec-ommend investigating the possibility of dry-rough ma-chining in order to take advantage of the protectivebuilt-up edge phenomenon.In summary, the literature review carried out showedthat the effect of more aggressive cutting parameters(speed, feed and depth of cut) still needs further re-search in order to improve the economics of the cuttingprocess. Also, several important parameters have beenoverlooked by previous researchers, among which arethe tool geometry and coolant application.3. Test material and cutting tools3.1.Workpiece materialThe machining investigations were carried out usingDuralcan F3S.20S Al/SiC metal-matrix composite. TheSiC particles had an average diameter of 12 mm. Table1 shows some of the physical and mechanical propertiesof A356-20%SiC PMMC. Prior to carrying out thecutting experiments, the test material was fully heat-treated to the T71 condition. The test material was inthe form of bars of 177.8 mm diameter and 305 mmlength.3.2.Cutting toolsVarious tool materials (coated carbide, Al2O3/TiCand PCD) and geometries were employed in the study.Oblique turning tests were carried out and differentcutting parameters were employed for each tool mate-rial. However, for the purpose of comparing tool wear,all cutting tests were carried out at a fixed volume ofmetal removed (300 mm3). Table 2 summarizes the tooldata.is because PCD grains with size 25 mm are easilypulled out of the cutting edge.Regarding the effect of the cutting parameters on thetool life, Lane et al. 1115,1719 attributed the in-crease in the wear of PCD tools (by abrasion) toincrease in kinetic energy gained by abrading SiC parti-cles. On the other hand, Brun et al. 7 attributed theincrease in tool wear in the thermal degradation of thetool material. Tool wear was found to be inverselyproportional to the feed rate 9. Tomac et al. 5attributed the increase in tool life at higher feed rates tothe thermal softening of the composite. The authorssuggest that the workpiece material becomes softer andthe SiC particles become pressed into the workpiece,causing less abrasion on the tool itself. However, Finnet al. 24 and Morin et al. 25 attributed the reductionin tool wear with greater feed rates to the reducedcontact between the cutting edge and the abrasive SiCparticles. Despite the controversy in explaining themechanism behind the tool wear at different feed rates,all researchers recommend using feed rates and depthsFig. 2. Effect of cutting speed on the cutting forces (PCD tool: r=1.6mm, a=0; square points: 6=670 m min1, doc=1.5 mm; roundpoints: 6=894 m min1, doc=1.5 mm).M. El-Gallab, M. Sklad/Journal of Materials Processing Technology83 (1998) 151158154Dry turning tests were carried out on a 10 HPStandard Modern NC lathe. The cutting force compo-nents (Fx, Fy, Fz) and tool wear were measured contin-uously for each combination of cutting parameters. Thetool forces were measured using a Kistler 3-componentdynamometer and the cutting conditions were selectedcarefully for each tool material. In some of the cuttingtests, the tool temperature was measured using K-typethermocouples that were glued onto the tool rake face,1 mm away from the cutting edge. The reliability of themeasurement techniques was checked constantly byrepeating the experiments and the results of each set ofexperiments were accepted if they exhibited a varianceof less than 5%. At the end of each cutting test, the toolwear was examined using a scanning electron micro-scope and the X-ray dispersion technique. The toolFig. 5. (a) Built-up edge on PCD tools (6=670 m min1, f=0.45mm rev1; doc=2.5 mm, r=1.6 mm); (b) as for Fig. 5(a), but for6=894 m min1.Fig. 4. (a) Built-up edge on PCD tools (6=670 m min1, f=0.25mm rev1, doc=2.5 mm, r=1.6 mm, a=0); (b) X-ray dispersionof built-up edge shown in Fig. 4(a).flank wear (VB) was measured using a toolmakersmicroscope.4. Results and discussion4.1.Effect of tool materialA series of preliminary tests was conducted to assesthe effect of tool material on the tool wear, cuttingforces and cutting temperature during the rough turn-ing of 20%SiC/Al PMMC. Fig. 1 shows that Al2O3/TiCtools suffered excessive wear in the form of edge chip-ping. Al2O3particles are pulled out by the abradingworkpiece particles, which have a greater Vickers hard-ness number (VHN) than the Al2O3particles (VHN forAl2O3TiC=2500 kgfmm2; VHN for SiC=3000 kgfmm2). Crater wear was also observed, which is due tothe widening of grooves that were caused by abrasion.Due to severe edge chipping, the cutting forces for theM. El-Gallab, M. Sklad/Journal of Materials Processing Technology83 (1998) 151158155Al2O3/TiC tool were much higher than those experi-enced by TiN coated tools (Table 3). The TiN coatingprovided some protection against the abrasive effects ofthe SiC particles. The superior performance of poly-crystalline diamond tools, compared to both Al2O3/TiCand TiN coated carbide tools, is attributed to their highabrasion resistance and high thermal conductivity,which led to lower cutting temperatures, as shown inTable 3. Therefore, all machinability studies carried outthereafter were concerned with the optimization of thecutting process using PCD tools.4.2.Effect of cutting parametersFigs. 2 and 3 show that as the cutting speed and/orthe depth of cut increase, the cutting forces decrease.This could be attributed to thermal softening of theworkpiece material. Another possible reason is due tothe changes introduced into the tool geometry upon theformation of built-up edge. Fig. 4(b) shows the X-raydispersion of the built-up material shown in Fig. 4(a).Fig. 7. (a) SEM image illustrating the wear on the PCD tool rake faceafter dissolving the BUE with NaOH (6=670 m min1, f=0.15 mmrev1, doc=1.5 mm, r=1.6 mm, a=0); (b) higher magnification ofrake face of the tool shown in Fig. 7(a).Fig. 6. (a) Built-up edge on PCD tools (6=670 m min1, f=0.35mm rev1, doc=1.5 mm, r=1.6 mm, a=0); (b) as for Fig. 6(a),but for doc=2.5 mm.Built-up edge was observed in all tools under all cuttingconditions. This is because particulate SiC/Al MMCshave all of the characteristics of materials that formFig. 8. Effect of cutting speed on the tool flank wear (PCD tool:r=1.6 mm, a=0; square points: 6=670 m min1, doc=1.5 mm;round points: 6=894 m min1, doc=1.5 mm).M. El-Gallab, M. Sklad/Journal of Materials Processing Technology83 (1998) 151158156Fig. 9. Effect of depth of cut on the tool flank wear (PCD tool:r=1.6 mm, a=0, 6=894 m min1; square points: doc=1.5 mm;round points: doc=2.5 mm).illustrate this point, in the case of a greater depth of cuta larger surface area of the tool flank face is exposed toabrasion.Increasing the feed rate had a beneficial effect. Asshown in Figs. 8 and 9, as the feed rate increases, thetool wear decreases. In the case of higher feed rates, fora fixed volume of metal removal, the tool surfaces willhave less contact with the abrasive PMMC. AnotherFig. 10. (a) Effect of PCD tool rake angle on tool flank wear (6=894m min1, doc=2.5 mm, r=1.6 mm; square points: 0; round points:5; star points, +5); (b) effect of PCD tool rake angle on thecutting forces (6=894 m min1, doc=2.5 mm, r=1.6 mm; squarepoints: 0; round points: 5; star points, +5); (c) SEM imageillustrating the PCD tool wear by pitting (6=670 m min1, doc=1.5mm, f=0.25 mm rev1, r=1.6 mm, a= +5).BUE (i.e. strain-hardened two-phase material underhigh temperature and pressure).At high cutting speeds (6=894 m min1(Fig. 5(b),a smaller BUE is formed, compared to the BUE formedat 6=670 m min1(Fig. 5(a); the height of the BUEwas measured perpendicular to the rake face) In con-trast, by increasing the depth of cut from 1.5 to 2.4mm, a large BUE is formed (Fig. 6(a,b), which couldbreak off the tool causing tool chipping and consequentadverse effects on the workpiece surface roughness anddimensional accuracy.Topographies of the tool indicate that the main wearmechanism of PCD is abrasion (manifested as groovesparallel to the chip flow direction). These grooves couldbe attributed to three factors. The first is that Al2O3isformed at the tool edge, which is hard enough toproduce grooving wear in the PCD. The second expla-nation for the PCD grooving is aluminium seizure andthe pull-out process of the PCD grain, as shown in Fig.7(a,b). The third possible reason behind PCD groovingis that SiC particles abrade the tools. Thus, PCD toolswith PCD grains larger than the grain size of the SiCparticles could better withstand the abrasion and mi-cro-cutting by the SiC particles. However, one shouldnote that as the size of the PCD grains increases, thefracture properties of the PCD tool deteriorates, due toan increased number of flaws in the material.The grooves that were formed on the tool face werefilled with the workpiece material. This adhering layersomewhat protected the tools rake face against furtherabrasion. Nonetheless, the tool flank face continued tobe subjected to abrasion. Hence, flank wear (Vb) wastaken as the tool life criterion with Vb1im=0.18 mm.Fig. 8 shows that as the cutting speed increases, theflank wear increases. This could be attributed to theincrease in the kinetic energy of the abrading particles,as previously hypothesized by Lane 17.Increasing the depth of cut leads to an increase in theflank wear (Fig. 9). This is attributed to enhancedabrasion by micro-cutting at the tool flank face. ToM. El-Gallab, M. Sklad/Journal of Materials Processing Technology83 (1998) 151158157Fig. 11. (a) SEM image illustrating the PCD tool wear by chipping(6=894 m min1, doc=1.5 mm, f=0.35 mm rev1, r=0.8 mm,a=0); (b) effect of tool nose radius on the tool flank wear (6=894min, doc=2.5 mm, a=0; tool FW: square points, r=1.6 mm;round pitch points, r=0.8 mm).wear in the case of negative rake angle, is the greatercutting forces encountered with such a rake angle (Fig.10(b). Moreover, the chips produced became caughtbetween the tool and the workpiece, causing damage tothe tool surface. Tools with positive rake angle showedirregular flank wear and excessive pitting in the cuttingedge zone, as shown in Fig. 10(c).The tool nose radius plays a key role in determiningthe wear mode of the tool. As the tool nose radius wasdecreased from 1.6 to 0.8 mm, the tool was found tosuffer from excessive chipping and crater wear, asshown in Fig. 11(a). This tool chipping leads to anincrease in cutting forces and flank wear, as shown inFig. 11(b). Tools with small nose radii are thus recom-mended for finishing operations where light cuttingparameters are used. Small nose radii are also expectedto yield better geometrical accuracy.5. ConclusionThe results of the machinability studies carried outon 20%SiC/Al particulate metal-matrix composites in-dicated the following.(1) The main tool wear mechanism is abrasion andmicro-cutting of tool material grains, manifested asgrooves on the tool face parallel to the chip flowdirection. All of the tools tested also suffered fromflank wear due to abrasion. There was no evidence ofchemical wear (e.g. by diffusion).(2) PCD tools sustained the least tool wear com-pared to TiN coated carbide tools and Al2O3/TiC tools.This is undoubtedly due to PCDs superior hardnessand wear resistance, as well as low coefficient of fric-tion, together with high thermal conductivity. This ledto lower cutting temperatures when PCD tools wereemployed. On the other hand, the TiN coated carbidetools and Al2O3/TiC tools suffered from excessivecrater wear and edge chipping.(3) The grooves formed on the rake face of PCDtools were filled with smeared workpiece material. Thisform of built-up edge is beneficial, since it protects thetool rake from further abrasion.(4) The cutting parameters play a key role in deter-mining the amount of tool flank wear, as well as thesize of the built-up edge. Tool wear is minimized byincreasing the feed rate, which leads to a reduction incontact between the tool and the abrading SiCp. Al-though increasing the cutting speed is expected to accel-erate the flank abrasion wear dramatically, the resultsindicated that the increase in wear is minimal. Highercutting speeds were associated with the increase in thecutting temperatures, which led to the formation of aprotective sticking thin layer of workpiece material onthe tool. This form of protective built-up edge wasprevented from growing in size by the increase speed ofadvantage gained by increasing the feed rate is thechange in chip form. At low feed rates, the chipsformed were continuous, also being difficult and haz-ardous to handle. At high feed rates and high depths ofcut ( f0.35, doc2.0 mm), the chips formed werediscontinuous. Despite the fact that in all experimentswith PCD tools high feed rates resulted in lower toolwear, a conclusive decision about the optimum cuttingparameters should take into consideration the effect ofthe cutting parameters on the surface integrity andsub-surface damage produced in the workpiece. Com-prehensive analysis of the surface integrity and chipmorphology will be presented in the Part II of thisresearch study.4.3.Effect of tool geometryThe tool rake angle had a profound effect on thewear of PCD tools. Three different rake angles wereexamined. As can be seen from Fig. 10(a), tools with 0rake angle out-performed positive and negative rakeangle tools. A possible reason for the increased flankM. El-Gallab, M. Sklad/Journal of Materials Processing Technology83 (1998) 151158158rubbing. Within the tested range of cutting parameters,the speed of 894 m min1, f=0.45 mm rev1anddepth of cut=1.5 mm resulted in the smallest toolwear. These cutting parameters enhance the productiv-ity rates upon using PCD tools.(5) PCD tools with nose radii=16 mm and rakeangle=0 also led to lower flank wear.AcknowledgementsThe authors would like to thank R. Bruski, fromDuralcan, USA and D. Dyer from GE Superabrasives,for supplying the test material and cutting tools and fortheir helpful comments throughout the research project.The experiments were conducted in the machining labo-ratories of the Intelligent Machines and ManufacturingR
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