点石文库
全部分类
  • 学术论文 >
    学术论文
    机械毕业设计 电气毕业论文 土木工程论文 医学论文 法学论文 管理论文 人力资源论文 计算机论文 软件工程 英语学论文 教育学论文 开题报告 冶金学论文 任务书 通信工程论文 生物学论文 毕业设计 毕业论文 文献综述 外文翻译 答辩PPT 参考文献 课程设计 期刊论文 减速器设计 其他
  • 机械毕业设计精选 >
    机械毕业设计精选
    含3D结构设计 结构设计/毕业设计 注塑模具设计(含模 注塑模具设计(含数 注塑模具设计 夹具设计类 夹具设计(机床类课 夹具设计(含三维模 数控工艺类 冲压模具(单工序) 冲压模具(复合模) 冲压模具(级进模) 压铸及其他模具类 matlab仿真类 ansys仿真类 plc控制类 单片机控制类 其他控制类 减速器课程类
  • 图纸模型 >
    图纸模型
    机械设备 零部件模型 交通运输 电子产品 生活用品 电子电工 五金工具 军工模型 建筑模型 模具图纸 钣金图纸 设计方案 机器人模型 航空航天 海洋船舶 艺术品/工艺品 CAD建筑图纸 文体用品 科幻模型 其他模型
  • 土木建筑 >
    土木建筑
    工程造价 室内装修 建筑图纸 规划方案 市政工程 园林工程 结构设计 环保行业 建筑设计 水电图 建筑标准 安全施工 建筑材料 技术标书 其他 施工组织
  • 行业资料 >
    行业资料
    机械类 仿真类 国家标准 企业标准 机械标准 金融经济 医学类 交通电力 全国省级标准 环保消防 机械行业标准 铁路行业标准 化工行业标准 建筑行业标准 城建市政标准 其他类
  • 办公文档 >
    办公文档
    PPT模板 工作汇报/总结 演讲稿/致辞 工作计划 活动策划 读后感/观后感 调研文书 招标投标 产品使用说明 会议纪要 商业策划 合同协议 商务礼仪 财务报表 广告营销 通知/申请 制度体系 个人简历 其他
  • 认证考试 >
    认证考试
    财会类 学历类 公务员/事业单位类 教师资格考试 技工职业考试 司法考试 网络工程师考试 质量工程师 成考/自考/函授 建筑类 外语类 资格类 外贸类 医药类 计算机类 其他
  • 教育辅导 >
    教育辅导
    幼儿教育 小学资料 中学资料 高中资料 成人高考 大学教育 研究生教育 自考/成人/函授 考试试卷 高中政治 高中生物 高中地理 高中数学 高中语文 高中外语 高中历史 其他
  • 生活休闲 >
    生活休闲
    运动健康 养生知识 服装配饰 科普知识 时政新闻 游戏攻略 旅游攻略 两性情感 美食烹饪 摄影摄像 其他 党团政务
  • 首页 点石文库 > 资源分类 > PDF文档下载
     

    2D 3D ground surface topography modeling considering dressing and wear effects in grinding process.pdf

    • 资源ID:3329       资源大小:2.09MB        全文页数:12页
    • 资源格式: PDF        下载权限:游客/注册会员/VIP会员    下载费用:1
    换一换
    游客快捷下载 游客一键下载
    会员登录下载
    下载资源需要1

    邮箱/手机:
    温馨提示:
    支付成功后,系统会根据您填写的邮箱或者手机号作为您下次登录的用户名和密码(如填写的是手机,那登陆用户名和密码就是手机号),方便下次登录下载和查询订单;
    特别说明:
    请自助下载,系统不会自动发送文件的哦;
    支付方式: 微信支付    支付宝   
    验证码:   换一换

          加入VIP,下载共享资源
     
    友情提示
    2、PDF文件下载后,可能会被浏览器默认打开,此种情况可以点击浏览器菜单,保存网页到桌面,既可以正常下载了。
    3、本站不支持迅雷下载,请使用电脑自带的IE浏览器,或者360浏览器、谷歌浏览器下载即可。
    4、本站资源下载后的文档和图纸-无水印,预览文档经过压缩,下载后原文更清晰   

    2D 3D ground surface topography modeling considering dressing and wear effects in grinding process.pdf

    2D/3D ground surface topography modeling considering dressing and wear effects in grinding process J.L. Jiang a , P.Q. Ge a,b,n , W.B. Bi a , L. Zhang a , D.X. Wang a , Y. Zhang a a School of Mechanical Engineering, Shandong University, Jinan 250061, China b Key Laboratory of High-effi ciency and Clean Mechanical Manufacture at Shandong University, Ministry of Education, Jinan 250061, China articleinfo Article history Received 9 May 2013 Received in revised form 8 July 2013 Accepted 11 July 2013 Available online 26 July 2013 Keywords Grinding Dressing Ground surface roughness Ground surface topography abstract Roughness is usually regarded as one of the most important factors to evaluate the quality of grinding process and ground surface. Many grinding parameters are affecting ground surface roughness with different extents, however, the most infl uential factors are wheel dressing and wear effects which were unfortunately not get seriously attention in the previous researches. On the other hand, as a most common indicator, roughness is only a statistical evaluation which is not enough to describe the topography characteristics of a surface, especially under higher demands on grinding process and functional ground surface quality. Thus in this work, a 2D and 3D ground surface topography models wereestablishedbasedonthemicroscopicinteractionmechanism modelbetweengrainsandworkpiece in grinding contact zone. In this study, besides grinding parameters,thewheel dressingand weareffects were taken into consideration, including dressing depth, dressing lead, geometry of diamond dressing tool and wear effects of both wheel and diamond dressing tool. A dressing and wear profi le line, L dw , which will describe how the grains’ shapes are changed, was established and added into a former 2D ground surface roughness prediction model. In order to obtain a better visual effect, a 3D topography modelwas established whichisbased onthe interaction situations in realgrindingprocess.Both2Dand 3D models will predict ground surface roughness more precisely and stably than traditional models by comparing with a dressing lead single-factor experiment. Results also showed that the selection of dressingparametersand dressingtoolscan refer tothe formed shape of L dw bycomparing with grinding depth, a e , and the dressing lead should be carefully chosen which will greatly infl uence ground surface topography the most.otherwise the experimental workload will be greatly increased. Furthermore, the empirical models have a limit on that they will be invalidated when the grinding condition is changed. Another type of models, analytical models, is based on the people’s understanding of the grinding process. Many of these Contents lists available at ScienceDirect journal homepage www.elsevier.com/locate/ijmactool International Journal of Machine Tools however,this model includes an empirical factor and does not describe the microstructure of the grinding wheel [5]. Currently, one of the most popular formulas of maximum undeformed chip thickness and grain number per unit area were proposed by Malkin [1] h m 4 Cr v w v sa e d e12 “ 12 ; C 1 LB 1 where Cisthe grainnumberperunitarea, Land Bare the lateral and longitudinal distance between two adjacent grains, respectively; r is the chip width-to-thickness ratio. However, the formulas above are obtained under these assumptions 1 all the grains are spherical and share the same size; 2 the locations of all the grains follow uniform distribution and the protrusion heights are the same. These assumptionsdonotrefl ectthecharactersofstochasticnatureandthe values of L,Bandrarediffi culttodetermine.Hou[6]usedprobability statistics method to analyze the mechanics of the grinding process. The numbers of contacting and cutting grains are determined for a givendepthofwheelindentationandtheundeformedchipthickness was described by the minimum grain diameter. In Hou′s research, it is assumed that the diameter of grains is under normal distribution and using only one variable x to express both grain size and grain protrusion, which means that the biggest grain has the highest protrusion and vice versa. However, this assumption is not corre- sponding with the actual interacting situation very well. The grains are random located within the wheel, so the size and protrusion heightofagrainareindependentwitheachotherandtheyshouldbe represented by two variables. Younis and Alawi [7] developed an undeformed chip thickness model which is described by Rayleigh′s probability density function p.d.f. and this model has been used extensively in the following research papers [8–11]. However, the Rayleigh′sp.d.f.isdefi ned by only one paremeter, β, which is hard to determine and has no clear physical meanings, and this model also cannot give a clear relationship between grinding conditions and undeformed chipthickness. Jiang and Ge [12] have been developed a comprehensive model which can successfully describe the micro- interacting mechanism between workpiece material and grains with different size, location and protrude height. The model is based on a new method of calculating grain number per unit grinding wheel volume and undeformed chip thickness. Their work gives a deeper insight into contacting situation in grinding zone which is hard to achieve using experimental methods. Although these models and simulation methods mentioned above can relatively well predict ground surface roughness with different extent, unfortunately, none of them can able to take the grindingwheeldressingandweareffectsintoconsiderationwhich actually have great infl uence on ground surface quality. The parameters of dressing process, such as dressing depth, dressing lead, dressing passes number and the geometry of dressing tool, Nomenclature A x,y undeformed chip cross-sectional area a d dressing depth per dressing pass a e grinding depth b w grinding width d e wheel diameter d gx grain diameter d tol total dressing depth d max maximum grain diameter d mean average grain diameter d min minimum grain diameter h cu,max maximum grain penetration depth, also undeformed chip thickness h cuz grain penetration depth h cuz,max maximum grain penetration depth l the grain location at the grinding contact length l c grinding contact length l con real contact length of a grain l cut the location when a grain starts cutting l m moving distance of grinding wheel l slid the location when a grain starts sliding l w workpiece length L A ,L A i ,L A n simulatedlinetodescribethegroundsurfaceprofi le L sd standard line to describe ideal ground surface N wheel structure number N lc number of grains in grinding contact zone N t total number of grains passing through line L A N v number of grains per unit grinding wheel volume n d dressing passes in a dressing process Q w ′ specifi c remove rate R a roughness, R a t total the time of L A changing into L A n V cut,xy removed workpiece material volume by grain G x,y v s wheel speed v w work speed x variable x expressing grain diameter x p the x-coordinate value of the intersecting point of line yy max and line ygx y protrude height of a grain y′ comp compensation amount y′ drw,min lowest point location of L dw Y′ CL center line of L A Δ t time interval of two adjacent grains δ coeffi cient, equals to d maxd min s standard deviation of normal distribution φ volume percentage of grains J.L. Jiang et al. / International Journal of Machine Tools fi ner dressings fi ne truing lead, slow dressing feed and small truing/dressing depth will produce higher densities of cutting asperities [22] and experiments in [23] showed that smaller dressing depth, dressing speed ratio and dressing cross-feed rate will produce smoother ground surface. At the same time, the wheel wear will also affect grinding process. Although the ground surface roughness will be reduced when the cutting edges are worn fl at, however their ability of removing material is weakened, thus in grinding contact zone, sliding and plowing between grains and workpiece material are mainly occurred. Here much energy of heat will be generated and majoring of the heat will transferred into workpiece material and cause thermal damage and other unexpected defects. Additionally, the roughness parameter cannot fully express the characteristics of surface topography. Roughness is essentially a statistical indicator of peaks and valleys on the surface, so the surfaces with different topographies may have the same rough- ness values. Therefore, when higher requirements on surface quality is put forward, for example some surfaces of optical elements or precision bearing raceways, the roughness indicator is not enough for expressing the topography of the surfaces. Towards to this problem, many researchers have established 2D/3D ground surface topography models which have better visual effects. Chen and Rowe [16–18] have discussed comprehen- sively the impact of single-point dressing on grinding process. Simulated grinding wheel topography was established taking account of the motion of the dressing tool, grain size, grain spacing, grain fracture and break-out. Then a 2D ground surface topography was obtained and contains features which bear a resemblance to the experimental surface. However, the method of calculating undeformed chip thickness has not given, and the infl uences of wear effect of grinding wheel and dressing tools was nottakenintoconsideration.IntheresearchofGongetal.[24],the virtual reality technology was applied to simulate ground surface, a virtual grinding wheel has been created and a 3D images were obtained and the dressing and wear effects were considered. However, in this model, only one parameter maximal remaining height was used to describe dressing effect and several coeffi - cients were introduced to describe grain diameter changing, grain geometrical shape, grain roughness and grain wear which value are lacking of theoretical basis. Aurich et al. [25] have developed a kinematic simulation of the grinding process model KSIM. Rely on KSIM, a series of important terms in grinding process can be obtained such as undeformed chip thickness and cross sectional area, grinding forces and ground surface topography. KSIM also consideredthedressingeffectshoweverinaquitesimplewaythat was just simply realized by cutting down the grain protrusion height of every single grain to a specifi ed limit dressing height which leads toa larger numberof grains with the same maximum grain protrusion height. Actually, this approach is more like a grinding wheel wear process. In the work of this paper, the interaction mechanism between grainsandworkpiecematerialarefi rstlymodeledanddiscussedin Section 2, which give a basis of the following simulations. In Section 3, a ground surface topography model considering dressing and wear effects was established which is a modifi ed model fromthe author′s former research which already tookall of the grinding parameters included. In Section 4, additionally, a 3D model of ground surface topography, which is more close to the grinding process, also considering dressing and wear and has bettervisualeffects,hasbeendeveloped.The3Dsimulatedsurface was compared and in good accordance with the measured work- piece surface under the same grinding conditions. It is found that both analytically and experimentally, the value of dressing leads has a greater impact compared with the other dressing parameters. 2. Interaction mechanisms between grains and workpiece material in grinding contact zone The detailed introduction of microscopic interaction mechan- ism was published in the author′s former paper [12], and the following are some basic principles. In grinding contact zone, a large amount of grains with random geometry and random distributed location contact with workpiece material with differ- ent microscopic interacting types, which will affect both grain number and single grain force calculation. Generally, it is believed that a grain will experience three stages when it goes through grinding contact zone sliding, plowing and cutting. But for different grains, the starting points of plowing and cutting stages are different for the reason that the critical conditions of plowing and cutting are related with grain sizes and penetration depths. Basedonthispoint,itisreasonabletosupposethatwhenagrainis at the end of grinding contact length, it may not enter the cutting stage and still in sliding or plowing stage, or even cannot contact with workpiece material in the whole contact length, so that different grains will experience different interacting situations which means that the starting points and the lengths of sliding, plowing and cutting stages are different between grains within grinding contact zone. Furthermore, these three types of grains may exist at the same location of the grinding contact zone. As shown in Fig. 1, there are nine grains in grinding contact zone. Because of the different sizes and protrusion heights, these grains contacting with workpiece material in different situation. Fig. 1 shows that 1 only Grain No. 7 contacts with workpiece material from the beginning of the grinding contact zone and the others do not; 2 Grains No. 1 and No. 3 share the same ‘grain′s realcontactlength,butthelengthsofsliding,plowingandcutting stagesaredifferentbetweenthetwo;3GrainNo.4andNo.9are end at plowing stage and Grain No. 2 is end at sliding stage; 4 Grain No. 5–No. 8 experience three stages, but their ‘grain′s real contact lengths′ and the starting points lengths of three J.L. Jiang et al. / International Journal of Machine Tools Manufacture 74 2013 29–40 31

    注意事项

    本文(2D 3D ground surface topography modeling considering dressing and wear effects in grinding process.pdf)为本站会员(王牌秘书)主动上传,点石文库仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。 若此文所含内容侵犯了您的版权或隐私,请立即通知点石文库(发送邮件至3339525602@qq.com或直接QQ联系客服),我们立即给予删除!

    温馨提示:如果因为网速或其他原因下载失败请重新下载,重复下载不扣分。




    关于点石文库 - 投资与合作 - 会员权益 - 联系我们 - 声明 - 人才招聘

    本站资源为会员上传分享,如有侵犯您的版权,请联系我们删除

    网站客服QQ:3339525602  网上上传投稿QQ群862612017

      copyright@ 2016-2020  dswenku.com 网站版权所有   

    经营许可证编号:湘ICP备18013834 


    收起
    展开