K211-支架加工工艺及钻Φ22和Φ14孔专用夹具设计【手动】【含高清CAD图纸和文档全套】
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机械加工工序卡片产品型号零件图号产品名称支架零件名称支架共12页第1页车间工序号工序名称材 料 牌 号机加工1、2铸造毛坯、时效处理HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸造11设备名称设备型号设备编号同时加工件数1夹具编号夹具名称切削液工位器具编号工位器具名称工序工时 /s准终单件12工步号工 步 内 容工 艺 装 备主轴转速切削速度进给量切削深度进给次数工步工时/sr/minm/minmm/rmm机动辅助1铸造2时效处理 设 计(日 期) 校 对(日期) 审 核(日期) 标准化(日期) 会 签(日期)标记处数更改文件号签 字 日 期标记处数更改文件号签 字 日 期装 订 线机械加工工序卡片产品型号零件图号产品名称支架零件名称支架共12页第2页车间工序号工序名称材 料 牌 号机加工3车46端面HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸造11设备名称设备型号设备编号同时加工件数车床CA61401夹具编号夹具名称切削液车床夹具工位器具编号工位器具名称工序工时 /s准终单件12工步号工 步 内 容工 艺 装 备主轴转速切削速度进给量切削深度进给次数工步工时/sr/minm/minmm/rmm机动辅助1车46端面车刀游标卡尺、工装XJ0018000.273000.211022 设 计(日 期) 校 对(日期) 审 核(日期) 标准化(日期) 会 签(日期)标记处数更改文件号签 字 日 期标记处数更改文件号签 字 日 期机械加工工序卡片产品型号零件图号产品名称支架零件名称支架共12页第3页车间工序号工序名称材 料 牌 号机加工4车34端面HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸造11设备名称设备型号设备编号同时加工件数车床CA61401夹具编号夹具名称切削液车床夹具工位器具编号工位器具名称工序工时 /s准终单件12工步号工 步 内 容工 艺 装 备主轴转速切削速度进给量切削深度进给次数工步工时/sr/minm/minmm/rmm机动辅助1车34端面车刀游标卡尺、工装8000.273000.211022 设 计(日 期) 校 对(日期) 审 核(日期) 标准化(日期) 会 签(日期)标记处数更改文件号签 字 日 期标记处数更改文件号签 字 日 期机械加工工序卡片产品型号零件图号产品名称支架零件名称支架共12页第4页车间工序号工序名称材 料 牌 号机加工5铣削54左端面HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸造11设备名称设备型号设备编号同时加工件数铣床X62W1夹具编号夹具名称切削液铣床夹具铣床夹具工位器具编号工位器具名称工序工时 /s准终单件12工步号工 步 内 容工 艺 装 备主轴转速切削速度进给量切削深度进给次数工步工时/sr/minm/minmm/rmm机动辅助1铣削54左端面硬质合金铣刀游标卡尺、工装8000.273000.211022 设 计(日 期) 校 对(日期) 审 核(日期) 标准化(日期) 会 签(日期)标记处数更改文件号签 字 日 期标记处数更改文件号签 字 日 期机械加工工序卡片产品型号零件图号产品名称支架零件名称支架共12页第5页车间工序号工序名称材 料 牌 号机加工6铣削54右端面HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸造11设备名称设备型号设备编号同时加工件数铣床X62W1夹具编号夹具名称切削液铣床夹具铣床夹具工位器具编号工位器具名称工序工时 /s准终单件12工步号工 步 内 容工 艺 装 备主轴转速切削速度进给量切削深度进给次数工步工时/sr/minm/minmm/rmm机动辅助1铣削54右端面硬质合金铣刀游标卡尺、工装8000.273000.211022 设 计(日 期) 校 对(日期) 审 核(日期) 标准化(日期) 会 签(日期)标记处数更改文件号签 字 日 期标记处数更改文件号签 字 日 期机械加工工序卡片产品型号零件图号产品名称支架零件名称支架共12页第6页车间工序号工序名称材 料 牌 号机加工7铣削左凸台HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸造11设备名称设备型号设备编号同时加工件数铣床X62W1夹具编号夹具名称切削液铣床夹具铣床夹具工位器具编号工位器具名称工序工时 /s准终单件12工步号工 步 内 容工 艺 装 备主轴转速切削速度进给量切削深度进给次数工步工时/sr/minm/minmm/rmm机动辅助1铣削左凸台硬质合金铣刀游标卡尺、工装8000.273000.211022 设 计(日 期) 校 对(日期) 审 核(日期) 标准化(日期) 会 签(日期)标记处数更改文件号签 字 日 期标记处数更改文件号签 字 日 期机械加工工序卡片产品型号零件图号产品名称支架零件名称支架共12页第7页车间工序号工序名称材 料 牌 号机加工8铣削右凸台HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸造11设备名称设备型号设备编号同时加工件数铣床X62W1夹具编号夹具名称切削液铣床夹具铣床夹具工位器具编号工位器具名称工序工时 /s准终单件12工步号工 步 内 容工 艺 装 备主轴转速切削速度进给量切削深度进给次数工步工时/sr/minm/minmm/rmm机动辅助1铣削右凸台硬质合金铣刀游标卡尺、工装8000.273000.211022 设 计(日 期) 校 对(日期) 审 核(日期) 标准化(日期) 会 签(日期)标记处数更改文件号签 字 日 期标记处数更改文件号签 字 日 期机械加工工序卡片产品型号零件图号产品名称支架零件名称支架共12页第8页车间工序号工序名称材 料 牌 号机加工9钻孔22HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸造11设备名称设备型号设备编号同时加工件数 钻床Z5251夹具编号夹具名称切削液钻床夹具钻床夹具工位器具编号工位器具名称工序工时 /s准终单件12工步号工 步 内 容工 艺 装 备主轴转速切削速度进给量切削深度进给次数工步工时/sr/minm/minmm/rmm机动辅助1钻孔22锥柄麻花钻游标卡尺、工装标卡尺、工装8000.273000.211022 设 计(日 期) 校 对(日期) 审 核(日期) 标准化(日期) 会 签(日期)标记处数更改文件号签 字 日 期标记处数更改文件号签 字 日 期机械加工工序卡片产品型号零件图号产品名称支架零件名称支架共12页第9页车间工序号工序名称材 料 牌 号机加工10镗孔38孔HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸造11设备名称设备型号设备编号同时加工件数 钻床Z5251夹具编号夹具名称切削液钻床夹具钻床夹具工位器具编号工位器具名称工序工时 /s准终单件12工步号工 步 内 容工 艺 装 备主轴转速切削速度进给量切削深度进给次数工步工时/sr/minm/minmm/rmm机动辅助1粗镗孔38孔硬质合金镗刀游标卡尺、工装8000.273000.211022精镗孔38孔硬质合金镗刀游标卡尺、工装8000.273000.21102 设 计(日 期) 校 对(日期) 审 核(日期) 标准化(日期) 会 签(日期)标记处数更改文件号签 字 日 期标记处数更改文件号签 字 日 期机械加工工序卡片产品型号零件图号产品名称支架零件名称支架共12页第10页车间工序号工序名称材 料 牌 号机加工11钻孔HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸造11设备名称设备型号设备编号同时加工件数 钻床Z5251夹具编号夹具名称切削液钻床夹具钻床夹具工位器具编号工位器具名称工序工时 /s准终单件12工步号工 步 内 容工 艺 装 备主轴转速切削速度进给量切削深度进给次数工步工时/sr/minm/minmm/rmm机动辅助1钻支架小端顶部孔3锥柄麻花钻游标卡尺、工装标卡尺、工装8000.273000.211022钻沉头孔锥柄麻花钻游标卡尺、工装标卡尺、工装8000.273000.21102 设 计(日 期) 校 对(日期) 审 核(日期) 标准化(日期) 会 签(日期)标记处数更改文件号签 字 日 期标记处数更改文件号签 字 日 期机械加工工序卡片产品型号零件图号产品名称支架零件名称支架共12页第11页车间工序号工序名称材 料 牌 号机加工12钻孔攻丝HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸造11设备名称设备型号设备编号同时加工件数 钻床Z5251夹具编号夹具名称切削液钻床夹具钻床夹具工位器具编号工位器具名称工序工时 /s准终单件12工步号工 步 内 容工 艺 装 备主轴转速切削速度进给量切削深度进给次数工步工时/sr/minm/minmm/rmm机动辅助1钻14孔锥柄麻花钻游标卡尺、工装标卡尺、工装8000.273000.211022倒角14孔锥柄麻花钻游标卡尺、工装标卡尺、工装8000.273000.21102 设 计(日 期) 校 对(日期) 审 核(日期) 标准化(日期) 会 签(日期)标记处数更改文件号签 字 日 期标记处数更改文件号签 字 日 期机械加工工序卡片产品型号零件图号产品名称支架零件名称支架共12页第12页车间工序号工序名称材 料 牌 号机加工13终检 入库HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸造11设备名称设备型号设备编号同时加工件数1夹具编号夹具名称切削液工位器具编号工位器具名称工序工时 /s准终单件12工步号工 步 内 容工 艺 装 备主轴转速切削速度进给量切削深度进给次数工步工时/sr/minm/minmm/rmm机动辅助1终检千分尺、游标卡尺2入库 设 计(日 期) 校 对(日期) 审 核(日期) 标准化(日期) 会 签(日期)标记处数更改文件号签 字 日 期标记处数更改文件号签 字 日 期机械加工工艺卡片工件名称支架工序号VIII零件名称支架零件号零件重量同时加工件数1材料毛坯牌号硬度型号重量钢板铸件3.07KG设备夹具辅助工具名称型号专用夹具立式钻床Z525安装工步安装及工步说明刀具量具走刀长度mm走刀次数切削深度mm进给量mm/r主轴转速r/min切削速度m/min基本工时min1钻22孔高速钢锥柄麻花钻游标卡尺22120.25375180.896设计者 指导老师共 1 页第 1 页机械加工工艺过程卡片零件号工序号工序名称设备夹具刀具量具名称型号名称规格名称规格名称规格 铸造时效处理铣上下端面立式铣床X51专用夹具高速钢端铣刀铣上下端面立式铣床X51专用夹具高速钢端铣刀卡尺钻,扩,孔卧式车床Z525专用夹具 高速钢锥柄麻花钻游标卡尺钻,扩,孔卧式车床Z525专用夹具高速钢锥柄麻花钻游标卡尺VII铣2-端面立式铣床X51专用夹具高速钢端铣刀游标卡尺VIII钻,扩2-孔立式钻床Z525专用夹具高速钢锥柄麻花钻游标卡尺IX 钻孔立式钻床Z525专用夹具高速钢锥柄麻花钻量规X去毛刺XI终检编号无锡太湖学院毕业设计(论文)相关资料题目: 基于液压夹紧的专用夹具设计 支架零件的工艺工装设计 信机 系 机械工程及自动化专业学 号: 0923816学生姓名: 孙 皓 指导教师: 韩邦华 (职称:副教授 ) (职称: )2013年5月25日目 录一、毕业设计(论文)开题报告二、毕业设计(论文)外文资料翻译及原文三、学生“毕业论文(论文)计划、进度、检查及落实表”四、实习鉴定表无锡太湖学院毕业设计(论文)开题报告题目: 基于液压夹紧的专用夹具设计 支架零件的工艺工装设计 信机 系 机械工程及自动化 专业学 号: 0923816 学生姓名: 孙 皓 指导教师: 韩邦华 (职称:副教授 ) (职称: )2012年11月24日 课题来源无锡某企业生产实际科学依据(包括课题的科学意义;国内外研究概况、水平和发展趋势;应用前景等)1、课题科学意义本课题是为了培养学生开发和创新机械产品的能力,要求学生能够结合零件加工工艺与常规普通铣床,针对在实际使用过程中存在的金属加工机床的工件夹紧及驱动问题,综合所学的机械理论设计与方法、气动与液压传动等理论知识,对快速、高效夹紧装置进行改进设计,进而实现金属加工机床的工件夹紧与驱动的半自动化控制。2、国内外研究概况及发展前景夹具从产生到现在,大约可以分为三个阶段:第一个阶段主要表现在夹具与人的结合上,这是夹具主要是作为人的单纯的辅助工具,是加工过程加速和趋于完善;第二阶段,夹具成为人与机床之间的桥梁,夹具的机能发生变化,它主要用于工件的定位和夹紧。人们越来越认识到,夹具与操作人员改进工作及机床性能的提高有着密切的关系,所以对夹具引起了重视;第三阶段表现为夹具与机床的结合,夹具作为机床的一部分,成为机械加工中不可缺少的工艺装备。在夹具设计过程中,对于被加工零件的定位、夹紧等主要问题,设计人员一般都会考虑的比较周全,但是,夹具设计还经常会遇到一些小问题,这些小问题如果处理不好,也会给夹具的使用造成许多不便,甚至会影响到工件的加工精度。我们把多年来在夹具设计中遇到的一些小问题归纳如下:清根问题在设计端面和内孔定位的夹具时,会遇到夹具体定位端面和定位外圆交界处清根问题。端面和定位外圆分为两体时无此问题,。夹具要不要清根,应根据工件的结构而定。如果零件定位内孔孔口倒角较小或无倒角,则必须清根,如果零件定位孔孔口倒角较大或孔口是空位,则不需要清根,而且交界处可以倒为圆角R。端面与外圆定位时,与上述相同。让刀问题在设计圆盘类刀具(如铣刀、砂轮等)加工的夹具时,会存在让刀问题。设计这类夹具时,应考虑铣刀或砂轮完成切削或磨削后,铣刀或砂轮的退刀位置,其位置大小应根据所使用的铣刀或砂轮的直径大小,留出超过刀具半径的尺寸位置即可。更换问题在设计加工结构相同或相似,尺寸不同的系列产品零件夹具时,为了降低生产成本,提高夹具的利用率,往往会把夹具设计为只更换某一个或几个零件的通用型夹具。由于现代加工的高速发展,对传统的夹具提出了较高要求,如快速、高效、安全等。基于液压夹紧的专用夹具设计,必须计算加工工序所受的切削力及切削力矩,按照夹紧方式进行夹紧力的计算,进而可以确定液压缸的负载,通过选定整个液压系统的压力,最终可以确定液压缸的各参数。随着机械工业的迅速发展,对产品的品种和生产率提出了愈来愈高的要求,使多品种,中小批生产作为机械生产的主流,为了适应机械生产的这种发展趋势,必然对机床夹具提出更高的要求。特别像后钢板弹簧吊耳类不规则零件的加工还处于落后阶段。在今后的发展过程中,应大力推广使用组合夹具、半组合夹具、可调夹具,尤其是成组夹具。在机床技术向高速、高效、精密、复合、智能、环保方向发展的带动下,夹具技术正朝着高精高效模块组合通用经济方向发展。研究内容通过实际调研和采集相对应的设计数据,分析金属切削加工过程中的机床工作台工件夹紧、驱动等方面的有关数据,再结合气动与液压传动的相关理论知识,完成液压夹紧传动方案分析及气压原理图的拟定,并进行主要功能元件的设计与选择及传动系统的验算校核等。拟采取的研究方法、技术路线、实验方案及可行性分析通过实践与大量搜集、阅读相关资料相结合,在对金属切削机床、金属切削加工、机械设计与理论及气动与液压传动等相关知识充分掌握后,对普通铣床的夹紧、驱动装置进行数学建模,并通过模拟实验分析建立普通铣床的驱动、夹紧装置的实体模型,设计液压专用夹具的驱动、夹紧装置,进行现场实验,以达到产品的最优化设计。研究计划及预期成果研究计划:2013年1月12日-2013年02月25日:按照任务书要求查阅论文相关参考资料,填写毕业设计开题报告书。2013年1月30日-2013年03月05日:填写毕业实习报告。2013年3月08日-2013年03月14日:按照要求修改毕业设计开题报告。2013年3月15日-2013年03月21日:学习并翻译一篇与毕业设计相关的英文材料。2013年3月22日-2013年04月28日:液压夹具设计。2013年4月29日-2013年05月21日:毕业论文撰写和修改工作。预期成果:通过现场调研、模拟、建模、实验、机器调试,达到产品的最优化设计,大大降低劳动强度和提高生产效率。在设计液压系统装置时,在满足产品工作要求的情况下,应尽可能多的采用标准件,提高其互换性要求,以减少产品的设计生产成本。特色或创新之处适用于现代加工企业安全、高效的液压夹具设计、夹紧装置的优化设计,可减少工人的劳动强度、降低机械加工工艺时间和机械零件的生产成本。已具备的条件和尚需解决的问题针对实际使用过程中存在的金属加工工艺文件编制、工件夹紧及快速、高效夹具设计问题,综合所学的机械理论设计与方法与液压与气动传动等方面的知识,实现适合于现代加工制造业、夹紧装置的优化设计,进而提高学生开发和创新机械产品的能力。指导教师意见 指导教师签名:年 月 日教研室(学科组、研究所)意见 教研室主任签名: 年 月 日系意见 主管领导签名: 年 月 日英文原文Basic Machining Operations and Cutting TechnologyMachine tools have evolved from the early foot-powered lathes of the Egyptians and John Wilkinsons boring mill. They are designed to provide rigid support for both the workpiece and the cutting tool and can precisely control their relative positions and the velocity of the tool with respect to the workpiece. Basically, in metal cutting, a sharpened wedge-shaped tool removes a rather narrow strip of metal from the surface of a ductile workpiece in the form of a severely deformed chip. The chip is a waste product that is considerably shorter than the workpiece from which it came but with a corresponding increase in thickness of the uncut chip. The geometrical shape of workpiece depends on the shape of the tool and its path during the machining operation. Most machining operations produce parts of differing geometry. If a rough cylindrical workpiece revolves about a central axis and the tool penetrates beneath its surface and travels parallel to the center of rotation, a surface of revolution is produced, and the operation is called turning. If a hollow tube is machined on the inside in a similar manner, the operation is called boring. Producing an external conical surface uniformly varying diameter is called taper turning. If the tool point travels in a path of varying radius, a contoured surface like that of a bowling pin can be produced; or, if the piece is short enough and the support is sufficiently rigid, a contoured surface could be produced by feeding a shaped tool normal to the axis of rotation. Short tapered or cylindrical surfaces could also be contour formed. Multiple-edged tools can also be used. Drilling uses a twin-edged fluted tool for holes with depths up to 5 to 10 times the drill diameter. Whether the drill turns or the workpiece rotates, relative motion between the cutting edge and the workpiece is the important factor. In milling operations a rotary cutter with a number of cutting edges engages the workpiece, which moves slowly with respect to the cutter. Plane or contoured surfaces may be produced, depending on the geometry of the cutter and the type of feed. Horizontal or vertical axes of rotation may be used, and the feed of the workpiece may be in any of the three coordinate directions. Introduction of Machining Machining as a shape-producing method is the most universally used and the most important of all manufacturing processes. Machining is a shape-producing process in which a power-driven device causes material to be removed in chip form. Most machining is done with equipment that supports both the work piece and cutting tool although in some cases portable equipment is used with unsupported workpiece. Low setup cost for small Quantities. Machining has two applications in manufacturing. For casting, forging, and press working, each specific shape to be produced, even one part, nearly always has a high tooling cost. The shapes that may be produced by welding depend to a large degree on the shapes of raw material that are available. By making use of generally high cost equipment but without special tooling, it is possible, by machining; to start with nearly any form of raw material, so long as the exterior dimensions are great enough, and produce any desired shape from any material. Therefore .machining is usually the preferred method for producing one or a few parts, even when the design of the part would logically lead to casting, forging or press working if a high quantity were to be produced. Close accuracies, good finishes. The second application for machining is based on the high accuracies and surface finishes possible. Many of the parts machined in low quantities would be produced with lower but acceptable tolerances if produced in high quantities by some other process. On the other hand, many parts are given their general shapes by some high quantity deformation process and machined only on selected surfaces where high accuracies are needed. Internal threads, for example, are seldom produced by any means other than machining and small holes in press worked parts may be machined following the press working operations. Primary Cutting Parameters The basic tool-work relationship in cutting is adequately described by means of four factors: tool geometry, cutting speed, feed, and depth of cut. The cutting tool must be made of an appropriate material; it must be strong, tough, hard, and wear resistant. The tool s geometry characterized by planes and angles, must be correct for each cutting operation. Cutting speed is the rate at which the work surface passes by the cutting edge. It may be expressed in feet per minute. For efficient machining the cutting speed must be of a magnitude appropriate to the particular work-tool combination. In general, the harder the work material, the slower the speed. Feed is the rate at which the cutting tool advances into the workpiece. Where the workpiece or the tool rotates, feed is measured in inches per revolution. When the tool or the work reciprocates, feed is measured in inches per stroke, Generally, feed varies inversely with cutting speed for otherwise similar conditions. The depth of cut, measured inches is the distance the tool is set into the work. It is the width of the chip in turning or the thickness of the chip in a rectilinear cut. In roughing operations, the depth of cut can be larger than for finishing operations. The Effect of Changes in Cutting Parameters on Cutting Temperatures In metal cutting operations heat is generated in the primary and secondary deformation zones and these results in a complex temperature distribution throughout the tool, workpiece and chip. A typical set of isotherms is shown in figure where it can be seen that, as could be expected, there is a very large temperature gradient throughout the width of the chip as the workpiece material is sheared in primary deformation and there is a further large temperature in the chip adjacent to the face as the chip is sheared in secondary deformation. This leads to a maximum cutting temperature a short distance up the face from the cutting edge and a small distance into the chip. Since virtually all the work done in metal cutting is converted into heat, it could be expected that factors which increase the power consumed per unit volume of metal removed will increase the cutting temperature. Thus an increase in the rake angle, all other parameters remaining constant, will reduce the power per unit volume of metal removed and the cutting temperatures will reduce. When considering increase in unreformed chip thickness and cutting speed the situation is more complex. An increase in undeformed chip thickness tends to be a scale effect where the amounts of heat which pass to the workpiece, the tool and chip remain in fixed proportions and the changes in cutting temperature tend to be small. Increase in cutting speed; however, reduce the amount of heat which passes into the workpiece and this increase the temperature rise of the chip m primary deformation. Further, the secondary deformation zone tends to be smaller and this has the effect of increasing the temperatures in this zone. Other changes in cutting parameters have virtually no effect on the power consumed per unit volume of metal removed and consequently have virtually no effect on the cutting temperatures. Since it has been shown that even small changes in cutting temperature have a significant effect on tool wear rate it is appropriate to indicate how cutting temperatures can be assessed from cutting data. The most direct and accurate method for measuring temperatures in high -speed-steel cutting tools is that of Wright & Trent, which also yields detailed information on temperature distributions in high-speed-steel cutting tools. The technique is based on the metallographic examination of sectioned high-speed-steel tools which relates microstructure changes to thermal history. Trent has described measurements of cutting temperatures and temperature distributions for high-speed-steel tools when machining a wide range of workpiece materials. This technique has been further developed by using scanning electron microscopy to study fine-scale microstructure changes arising from over tempering of the tempered martens tic matrix of various high-speed-steels. This technique has also been used to study temperature distributions in both high-speed -steel single point turning tools and twist drills. Wears of Cutting Tool Discounting brittle fracture and edge chipping, which have already been dealt with, tool wear is basically of three types. Flank wear, crater wear, and notch wear. Flank wear occurs on both the major and the minor cutting edges. On the major cutting edge, which is responsible for bulk metal removal, these results in increased cutting forces and higher temperatures which if left unchecked can lead to vibration of the tool and workpiece and a condition where efficient cutting can no longer take place. On the minor cutting edge, which determines workpiece size and surface finish, flank wear can result in an oversized product which has poor surface finish. Under most practical cutting conditions, the tool will fail due to major flank wear before the minor flank wear is sufficiently large to result in the manufacture of an unacceptable component. Because of the stress distribution on the tool face, the frictional stress in the region of sliding contact between the chip and the face is at a maximum at the start of the sliding contact region and is zero at the end. Thus abrasive wear takes place in this region with more wear taking place adjacent to the seizure region than adjacent to the point at which the chip loses contact with the face. This result in localized pitting of the tool face some distance up the face which is usually referred to as catering and which normally has a section in the form of a circular arc. In many respects and for practical cutting conditions, crater wear is a less severe form of wear than flank wear and consequently flank wear is a more common tool failure criterion. However, since various authors have shown that the temperature on the face increases more rapidly with increasing cutting speed than the temperature on the flank, and since the rate of wear of any type is significantly affected by changes in temperature, crater wear usually occurs at high cutting speeds. At the end of the major flank wear land where the tool is in contact with the uncut workpiece surface it is common for the flank wear to be more pronounced than along the rest of the wear land. This is because of localised effects such as a hardened layer on the uncut surface caused by work hardening introduced by a previous cut, an oxide scale, and localised high temperatures resulting from the edge effect. This localised wear is usually referred to as notch wear and occasionally is very severe. Although the presence of the notch will not significantly affect the cutting properties of the tool, the notch is often relatively deep and if cutting were to continue there would be a good chance that the tool would fracture. If any form of progressive wear allowed to continue, dramatically and the tool would fail catastrophically, i. e. the tool would be no longer capable of cutting and, at best, the workpiece would be scrapped whilst, at worst, damage could be caused to the machine tool. For carbide cutting tools and for all types of wear, the tool is said to have reached the end of its useful life long before the onset of catastrophic failure. For high-speed-steel cutting tools, however, where the wear tends to be non-uniform it has been found that the most meaningful and reproducible results can be obtained when the wear is allowed to continue to the onset of catastrophic failure even though, of course, in practice a cutting time far less than that to failure would be used. The onset of catastrophic failure is characterized by one of several phenomena, the most common being a sudden increase in cutting force, the presence of burnished rings on the workpiece, and a significant increase in the noise level. Mechanism of Surface Finish Production There are basically five mechanisms which contribute to the production of a surface which have been machined. These are:(l) The basic geometry of the cutting process. In, for example, single point turning the tool will advance a constant distance axially per revolution of the workpiecc and the resultant surface will have on it, when viewed perpendicularly to the direction of tool feed motion, a series of cusps which will have a basic form which replicates the shape of the tool in cut. (2) The efficiency of the cutting operation. It has already been mentioned that cutting with unstable built-up-edges will produce a surface which contains hard built-up-edge fragments which will result in a degradation of the surface finish. It can also be demonstrated that cutting under adverse conditions such as apply when using large feeds small rake angles and low cutting speeds, besides producing conditions which lead to unstable built-up-edge production, the cutting process itself can become unstable and instead of continuous shear occurring in the shear zone, tearing takes place, discontinuous chips of uneven thickness are produced, and the resultant surface is poor. This situation is particularly noticeable when machining very ductile materials such as copper and aluminum. (3) The stability of the machine tool. Under some combinations of cutting conditions; workpiece size, method of clamping ,and cutting tool rigidity relative to the machine tool structure, instability can be set up in the tool which causes it to vibrate. Under some conditions this vibration will reach and maintain steady amplitude whilst under other conditions the vibration will built up and unless cutting is stopped considerable damage to both the cutting tool and workpiece may occur. This phenomenon is known as chatter and in axial turning is characterized by long pitch helical bands on the workpiece surface and short pitch undulations on the transient machined surface. (4)The effectiveness of removing swarf. In discontinuous chip production machining, such as milling or turning of brittle materials, it is expected that the chip (swarf) will leave the cutting zone either under gravity or with the assistance of a jet of cutting fluid and that they will not influence the cut surface in any way. However, when continuous chip production is evident, unless steps are taken to control the swarf it is likely that it will impinge on the cut surface and mark it. Inevitably, this marking besides looking. (5)The effective clearance angle on the cutting tool. For certain geometries of minor cutting edge relief and clearance angles it is possible to cut on the major cutting edge and burnish on the minor cutting edge. This can produce a good surface finish but, of course, it is strictly a combination of metal cutting and metal forming and is not to be recommended as a practical cutting method. However, due to cutting tool wear, these conditions occasionally arise and lead to a marked change in the surface characteristics. Surface Finishing and Dimensional Control Products that have been completed to their proper shape and size frequently require some type of surface finishing to enable them to satisfactorily fulfill their function. In some cases, it is necessary to improve the physical properties of the surface material for resistance to penetration or abrasion. In many manufacturing processes, the product surface is left with dirt .chips, grease, or other harmful material upon it. Assemblies that are made of different materials, or from the same materials processed in different manners, may require some special surface treatment to provide uniformity of appearance. Surface finishing may sometimes become an intermediate step processing. For instance, cleaning and polishing are usually essential before any kind of plating process. Some of the cleaning procedures are also used for improving surface smoothness on mating parts and for removing burrs and sharp corners, which might be harmful in later use. Another important need for surface finishing is for corrosion protection in a variety of: environments. The type of protection procedure will depend largely upon the anticipated exposure, with due consideration to the material being protected and the economic factors involved. Satisfying the above objectives necessitates the use of main surface-finishing methods that involve chemical change of the surface mechanical work affecting surface properties, cleaning by a variety of methods, and the application
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