15t自调式焊接滚轮架设计【11张CAD高清图纸和说明书】【GC系列】
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开题报告课题名称15t焊接式滚轮架设计课题来源导师课题课题类别工程设计一、论文资料的准备随着焊接技术的高速发展，对焊接生产的机械化和自动化提出了越来越高的要求。焊接机械设备的需求量也越来越大。焊接滚轮架设备正是为了满足市场需求而设计生产的。它是借助于焊件与主动轮之间的摩擦力来带动圆筒形焊件旋转的装置。主要用于圆筒形焊件的焊接和装配。焊接滚轮架是主动轮与工件之间的摩擦力带动筒形工件旋转的变为机械。它主要用于筒形工件的纵向焊缝，环向焊缝的装配和焊接作业。也可以在焊接滚轮架上进行修整，割孔及探伤作业。滚轮架是容器生产中最常用的工艺装备。焊接滚轮架按结构形式分为两类：第一类是长轴式滚轮架，主动滚轮架装置在一根电动机驱动的轴上；从动滚轮架在另一根公共轴上。滚轮中心距离可以调节，适用于焊接薄壁、长度大的筒形工件。第二类是组合式滚轮架：主动滚轮架与从动滚轮架各自独立，可根据工件的长度任意组合，使用方便灵活，适用性强，是目前运用最广泛的滚轮架之一。焊接滚轮架（主动滚轮架，从动滚轮架）；主动滚轮架由底座、滚轮、传动减速机构、控制系统组成，从动滚轮架由底胎和滚轮组成。焊接滚轮架主动滚轮架和从动滚轮架都是独立的，它们之间可根据工件的重量和长度任意的组合，其组合比列可以是一主一从的组合，也可以是一主两从、一主三从的组合，使用起来方便灵活，对焊件的适应性强。主动架主要由底座、滚轮、传动减速机构、控制系统组成，从动架主要由底胎和滚轮组成。滚轮架有以下特点：1) 课根据焊接的重量、长度任意组合，使用方便灵活。2) 在规定范围内自动调节滚轮中心距，适用于不同直径的焊件，圆筒焊件放置平稳。3) 可采用可控硅供电直流电动机驱动，无极调速、焊速范围大、速度稳定。4) 适用性强，使用广泛。5) 采用组合式滚轮，钢轮外包橡胶传动平稳、摩擦力大、寿命长。6) 对工件轮压小，可避免工件表面产生冷作硬化。焊接滚轮架多采用直流电动机驱动，降压调速。这种方式沿用已久，技术很成熟，电动机的机械特性比较硬，起动力矩较大，但是目前滚轮架使用的最广泛的拖动调速方式。确定是电动机结构复杂，调速范围较窄，一般很转矩的调速范围为1：10左右。低速时速度不稳定，有爬行现象。也有滚轮架是采用交流异步电动机拖动，变频调速。近几年随着晶体管变频器性能的完善以及价格的下降，采用交流电动机驱动变频调速的滚轮架也日趋增多。优点是调速范围宽，可达1:20，线转动平滑性好，低速特性硬。缺点是低速段过载倍数降低太大，变频电源价格也较高，但随着电动机额定功率的增加，价格上升则相对平缓，所以在重型焊接滚轮架上采用交流异步电动机拖动和变频调速比较合适。由于制造工艺、材料性能等因素的影响，另外，一对重型焊接滚轮架的金属滚轮一般采用铸铁或者合金钢球墨铸铁制成表面硬度为50HRC的滚轮。滚轮直径大多在200-700之间。国外滚轮架品种多、系列全。我国在1990年就已经颁布了焊接滚轮架的行业标准（ZBJ/T33003-1990）。焊接滚轮架存在一个轴向窜动的问题，只有当滚轮和焊件都是理想的圆柱体且各滚轮尺寸一致，转动轴线都在同一水平面内并与焊件平行时才能实现。理论和实践都表明：影响焊件作轴向窜动的主要因素是滚轮各轴线的平行度。因此要做到：主、从动滚轮架都位于同一中心线上各滚轮轴线都在同一水平面内且相互平行滚轮间距相等。目前有三种机构可解决此问题：1) 顶升式执行机构；2) 偏移式执行行机；3) 平移式执行机构。在国内一些大型或较复杂的焊接机械装备已有专业厂生产，可根据生产需要选购和订购焊接机械设备设计就是一种机械设计，但这种机械设计必须充分考虑，焊接工艺的基本特点并满足装配和焊接工艺的特殊要求，一般的设计原则与要求是：1.工艺原则焊接产品总是由两个以上的零、部件组成，由于施焊方便，或易于控制焊接变形等原因，装配和焊接两道焊接工序可能是先装完后再焊，也可能是边装边焊，所以设计装备应能适应这种情况。焊接式局部加热过程，不可避免产生焊接应力与变形，在装备上设置定位器和夹紧器件时要充分考虑焊接应力和变形的方向。通常在焊件平面内的伸缩变形不作限制，通过焊件留收缩余量方法让其自由的收缩；而焊接面外的焊接变形，如角变形、弯曲应力变形或波浪变形等应用夹具加以控制；有时还要利用夹具作出反变形的工艺措施，这些都是要求定位和夹紧器来实现。用电作热源的焊接方法，一般都要求焊件本身作为焊接回路中的一个电极，就可能要求焊接装备具有导电或绝缘功能。当焊接电流很大时，导电部分还需有散热措施；真空电子束焊接所用的夹具不得用点磁性材料制作，也不得有带剩磁，以免影响电子束聚焦等。明弧焊接时，难免产生烟尘、金属或熔渣的飞溅物，他们会损坏工装上外露的光滑工作面，需有遮掩措施等。2.安全可靠原则安全可靠原则指装在可用期内绝对安全可靠，凡是受力构件都应具有足够的强度和刚度，足以承受焊件重力和因限制焊件变形而引起的各方向的反作用力等。夹紧时不破坏焊件的既定位置；夹紧后既不让焊件松动滑移，友不使焊件的拘束度过大以免产生较大的约束应力；夹紧机构应能自锁等。3.方便原则装备必须便操作和施工，能使装配和焊接过程简化，工人劳动强度降低到最低，工件装上和卸下方便；有供焊枪、面罩、焊接机头等进出和摆动的空间以及工人自由操作的位置，也便于中间进行质量检测；装备上各种机件操作要轻巧灵便；定位、夹紧和松开过程要省力而快速；对易损零、部件便于维修和更换等。4.经济原则所设计的装备必须易于制造，投资少，制造成本低，回收期短。尽量选用通用化、标准化零、部件；在一个夹具上定位器件和夹紧机构的结构形式不宜过多也不应过于复杂；使夹具和机械具有较好的制造工艺性能和较高的机械效率；装备在使用时能源消耗和管理费用少等二、本课题的目的（重点及拟解决的关键问题）目的：毕业设计是工科大学生完成学业中最重要的实践环节，是将在大学学到的理论知识系统化、条理化、实用化最关键的一环。通过本毕业设计培养学生综合运用所学的基础理论、专业知识和基本技能，提高分析与解决实际问题的能力；较复杂工程计算的工作能力；计算机绘图的工程图绘制能力。掌握一般机械机构的设计思路、方法和步骤，掌握常用工程材料的性能和选配能力。尽快完成学生到工程技术人员的过渡。 重点：在设计过程中重点是机架总体结构的设计，减速器的选择，各零部件（减速器、轴、齿轮、轴承、联轴器、键）的设计，和机架的设计。关键问题：1.第一步的总体结构设计。总体结构不仅关系到成品的安装于运输还关系到后面零部件的尺寸约束。2.最后的机架设计。3. 焊接滚轮架轴窜机理及影响因素。三、主要内容、研究方法、研究思路主要内容：焊接滚轮架是借助主动滚轮与焊件之间的摩擦力,带动焊件旋转的变位机械。焊接滚轮架主要用于筒形焊件的装配与焊接。自调式焊接滚轮架可根据焊件的直径自动调整滚轮的间距。焊接滚轮架由主动滚轮架和从动滚轮架两大部分组成。本设计要求对15t焊接滚轮架做总体设计和主动滚轮架和从动滚轮架等机构做结构设计。原始数据：1.最大载重量：15000kg 2.工件直径：5005300mm 3.滚轮圆周速度：848m/h 4.滚轮直径：（钢轮+胶轮+钢轮）380mm+400mm+380mm 5.滚轮总宽度：250mm技术要求：1. 焊接滚轮架要有较宽的调速范围，稳定的焊接运行速度，以及良好的结构刚度；2.对焊件的直径和形状要有一定的适用性；3.结构整体要有较高的强度和抗冲击性能；4.无论是高速回转还是低速回转，其转速应平稳、均匀。研究方法：在类比别的机型的同时参观了不同滚轮架的形式和驱动方式,在这些基础上进行改造和设计。研究思路：首先，进行滚轮架的总体设计。根据所给的参数确定出两滚轮支架之间的距离，滚轮架臂长，和滚轮架在工作时臂架的反转角度。确定出滚轮架大体的外部轮廓尺寸，并分析焊接滚轮架轴窜机理及影响因素。其次，对滚轮架进行受力分析。根据滚轮架总体结构的尺寸和滚轮的尺寸分最大工件尺寸和最小工件尺寸两种情况进行受力分析，后面各零部件的设计打好基础。为电机选择提供数据。再次，各零部件的设计。根据所选电机确定减速器的传动比，再根据需要的传动比选择电机，最后校核电机的功率及转矩。根据受力分析结果初估轴径，再根据之前总体设计中外部轮廓的尺寸及轴上零件进行轴结构的设计。根据臂架的长度及传动比的需要设计三个传动齿轮，在本设计中减速器的传动比已经满足要求，齿轮只起传递功率和转矩的作用。最后设计连接这些零部件的连接件（轴承、键、联轴器），完成整套机械的组装。最后，设计机架。机架的作用是支撑所有工作部件，承受工件及工作装置传来的力和和转矩。机架为完成工作装置的定位，提供实现工作装置的正常工作的条件。四、总体安排和进度（包括阶段性工作内容及完成日期）3月25日-4月7日： 确定方案、修改方案、最终通过方案。（二周）设计人应随时将方案交指导老师审批，方案通过则继续进行，通不过则修改方案，在两周内必须通过方案。4月8日-5月5日： 撰写计算书。（四周）严格按规范要求撰写计算书，包括页面布置、字体、内容、插图等。插图使用AUTOCAD绘制，图文并茂，计算正确完整。5月6日-6月9日： 绘制工程图。（五周）图量符合要求。6月10日-6月16日：整理毕业设计资料，准备答辩6月17日-6月21日：毕业答辩五、主要参考文献1王政. 焊接工装夹具及变位机械性能、设计、选用. 北京：机械工业出版社，20032王政等. 焊接工装夹具及变位机械图册. 北京：机械工业出版社，20063成都电焊11机研究所等. 焊接设备选用手册. 北京：机械工业出版社，20064雷玉成等. 焊接成型技术. 北京：化学工业出版社，20045陈裕川. 现代焊接生产实用手册. 北京：机械工业出版社，20056成大先主编. 机械设计手册单行本 轴及其联接.北京：化学工业出版社，19977成大先主编.机械设计图册（上、下册）.北京：化学工业出版社，19978陆玉，何在州，佟延伟编.机械设计课程设计.北京：机械工业出版社，20039吴宗泽主编. 机械设计实用手册-2版. 北京：化学工业出版社，200310陈祝年编. 焊接工程师手册.北京：机械工业出版社，200611濮良贵等编.机械设计（第八版）. 北京：高等教育出版社，200612孙恒, 陈作模等编. 机械原理. 北京：高等教育出版社，200613陈祝年编.机械零件设计手册. 北京：机械工业出版社，200414徐格宁主编. 机械装备金属结构设计第2版. 北京：机械工业出版社，200915王伯平主编. 互换性一测量技术基础第3版. 北京：机械工业出版社，2009 16大连理工大学工程图学教研室编第六版. 北京：高等教育出版社，200717陆玉主编. 机械设计课程设计. 北京：机械工业出版社，2006指导教师意见： 指导教师签名： 日期：教研室意见：教研室主任签名： 日期：系意见： 系领导签名： 日期：系盖章课题来源：导师课题、社会实践、自选、其他课题类别：工程设计、施工技术、新品开发、软件开发、科学实验、毕业论文。摘要随着焊接技术的高速发展，对焊接生产的机械化和自动化提出了越来越高的要求。焊接装备就是在焊接生产中与焊接工序相配合,有利于是实现焊接生产机械化,自动化,有利于提高装配焊接质量,促使焊接生产过程加速进行的各种辅助装置和设备。焊接机械设备的需求量也越来越大。焊接机械设备的需求量也越来越大。焊接滚轮架设备正是为了满足市场需求而设计生产的。焊接滚轮架是借助主动滚轮与焊件之间的摩擦力来带动焊接旋转的变为机械。焊接滚轮架主要用于筒形焊件的装配与焊接。焊接滚轮架按结构形式分为两类：第一类是长轴式滚轮架。第二类是组合式滚轮架。按调节方式分为自调式、非自调式。自调式焊接滚轮架可以根据焊件直径自动调整滚轮架的间距。本文主要是对15t自调式焊接滚轮架进行设计，并对轴、键等主要构件进行校核。结果表明各主要部件符合要求。该滚轮架结构简单，使用方便灵活，对焊件的适应性很强。设计中充分考虑了滚轮架的合理性和经济性等因素。关键词：焊接 工装夹具 滚轮架ABSTRACTAs the welding technology developed, more and more higher quality is needed to mechanization and automation of welding production and welding process. Welding equipment is a machine which is used in welding production and welding process, and it is conducive to welding production mechanization and automation, to improving assembly welding-quality. Then it could speed up the process of welding production of the various assistive devices and equipment. Welding equipments requirement is in big mass. Welding roller is designed for the requirement of the market. Welding roller is used initiative and welding pieces of the wheel between the Mount relay driven welding rotating mechanical deformation. Welding roller stands for the main pieces of tube welding and welding assembly. Welding roller standing by structural form is divided into two categories: the first category is long axis-wheel frame, the second category is modular roller frame. According to the regulating mode is divided into self-adjusting, non-self-adjusting. Self-adjusting welding roller can adjusting the distance of the welding roller according to the diameter of the work. In this paper, fifteen tons of self-adjusting welded wheel for the design, as well as axial, bond and other main component of checking. The results showed that the main component to meet the requirements. The roller frame structure is simple, flexible, adaptive welded pieces of a strong, which is the most widely used form of the structure. And it could be fully considered the roller frame reasonable and economic, and other factor.KEY WORDS: weld frock clamp turning rolls目 录第1章 前言11.1焊接滚轮架的发展11.2 滚轮架的工作原理及类型31.3 滚轮架的设计原则及要求4第2章 总体设计62.1 滚轮架的组成 6 2.2 滚轮架各总体参数的确定7 2.3 焊接滚轮架轴窜机理及影响因素10第3章 受力分析15 3.1 工件直径最大时受力分析15 3.2 工件直径最小时受力分析16第4章 电机选择17 4.1 电动机的类型17 4.2 电动机的转速及功率18 4.3 滚轮架电机选择计算19第5章 传动比分配及减速器选择205.1 减速器选择考虑因素205.2 滚轮架中传动比分配及减速器选择21第6章 齿轮设计计算236.1 齿轮设计准则236.2 齿轮材料的选择及参数确定236.3 齿轮设计计算25第7章 轴的设计计算317.1 轴的分类317.2 轴的设计步骤317.3滚轮架中各轴的设计34第8章 联轴器的选择398.1 联轴器的简介398.2 联轴器的选择计算39第9章 轴承设计429.1 轴承的组成及分类429.2 滚动轴承的代号429.3轴承的类型的选择方法439.4轴承的选择计算44第10章 键的选择4610.1 键的分类及工作原理4610.2 键的强度校核4710.3键的选择计算47第11章 机架设计49第12章 毕业设计小节50参考文献52附：英文原文英文翻译毕业实习报告附 件：1、外文原文；2、外文资料翻译译文。指导教师评语：签字： 年 月 日注：请将该封面与附件装订成册。1、 外文原文（复印件）2、外文资料翻译译文第15章 锯和锯削15.1简介锯削曾被认为是次要的加工方法，一般用于为别的加工工序做准备而切削棒料。在近些年，由于一些新的锯床的发展，更好的锯齿材料使锯削成为更加高效，灵活，经济的加工方法。现在很多情况下带锯是零件特定形状成型的主要加工方式。图15.1: 典型的锯削工艺（Courtesy: Clausing Industries, Inc.）当使用正确的锯床和锯片时，锯削是最经济的金属切削方式之一。锯削的切口很窄，在锯削过程中几乎没有切屑产生。当带锯用来切削复杂外形轮廓时，只有很少一部分金属作为切屑的形式从零件表面除去。因此用于切削大量余量金属的动力是很小的。15.2锯削锯削中通过带有一系列很小间距的齿（称作锯齿）的工具在工件中切入狭长的口子。锯削一般用于把零件分割成两部分或者更多的部分，或者去除零件多余的部分。这些加工经常被称作切断加工，因此许多加工工艺中在生产序列的某些地方要求有切断加工，锯削是很重要的加工方法。锯削是基本上是很简单的加工方法。当锯齿在在工件中移动是，每个齿都进行切削。根据工件的尺寸和厚度，在同一时间进行切削的齿数在2到10之间变化或者更多。锯削是连续切削或者往复切削。在图15.1中所示为典型的锯削加工。合适的锯齿和加工条件选择之前应该知道切削速度和材料的特点。几乎在每个加工车间都可以看到锯床，锯床是一类高效的加工机床。15.3锯片 所有的锯齿既拥有共同特点也有它的专业用语。一些术语在图15.2中给出,另一些下面将作出介绍：图15.2: 锯的特点和专业术语前角：在大部分锯齿中前角是零度。如图15.2中所示一些锯齿拥有正前角。宽度：锯齿的宽度是包括所齿在内的总宽度。固定装置：锯刀的固定装置指的是补偿锯齿的设备以至于刀片可以清理切槽。切缝:切缝是由锯片和被切除的材料形成的切削宽度。锯齿的厚度称作厚度规格。齿距：锯的齿距是指两个相邻的锯齿的最高点之间的距离。在锯齿中以英寸定义。15.3.1锯片材料锯片用以下介绍的各种材料制作：碳钢：一般用于小批量，低速工作。这些罪便宜的刀具或许更耐磨。高速钢：高速钢要花费三倍于碳钢的价钱，但是它更耐磨而且加工难加工的材料时必须使用。高速边缘：这是碳钢刀刃，把HSS锯齿焊接在一个狭长的材料上制作而成。这种锯片坚韧，价格也不贵，被广泛使用，适合切削大部分材料。碳化钨刀尖：尺寸很小。仅仅用在大型的，刚性好的锯床用来加工难加工的材料且生产效率高。15.3.2锯片选用选择适合的特定加工的带锯首先应该了解的是将要加工的是什么材料。像硬度、加工性能、加工的形状、加工部位这些因素都应该考虑。一旦确定将要加工的是什么材料，机床上的选择器就可以用来选择合适的锯，切削速度。控制面板和选择器的确很有用，但是，操作者又必须对每个锯削工序中切削速率，刀具寿命，精度三种变量做出选择。一般来说，增加其中一个变量会导致另一个或两个会下降。例如：增加切削速率将会减少刀具寿命和精度。15.3.3锯片焊接几乎所用立式金属切削带锯有电焊片附件。它一般安装在床身上靠近操作者左手的一边，由一切齿、小砂轮和并对焊机组成。叶片焊接附件把锯片原材料制作成带锯或者用来焊接锯片，这些是在工件孔中进行内孔切削的锯片。在锯片上应该强调焊接质量的重要性。因不合格焊接、不恰当的联结、不恰当的热处理引起的缺陷不仅浪费时间而且存在潜在的危险。对焊机：电阻式对接焊机上发现几乎所有立式带锯都是通过使电流流过锯条两端施加压力来完成操作。刀片端部大电阻使热量来不及扩散就导致金属瞬时加热到白炙状态。提供了用于退火的焊接接头。当操作者按下按钮很短时间，电流流过接好的接头直到连接接头变成暗红色。当缓慢冷却时接头得到退火。15.4锯削设备图 15.3: 三种基本的锯的加工方法: (a) 钢锯, (b) 立式带锯 (c)卧式带锯在大部分锯削操作中，工件被静止固定，锯向工件移动。如图15.3示一样，根据锯的移动方式有三种基本的锯削工艺：15.4.1钢锯钢锯围绕工件的往复直线运动。这种锯削的方法经常用作于切断。切割只发生在锯的前进行程。由于这种断续切削的锯切削比其他锯削效率要低。钢锯课分为手动锯和电锯。电钢锯提供了在理想速度和进给率条件下操作锯的驱动原理。图 15.4a: 半自动锯电动钢锯：电动钢锯是最早也是最贵的一种锯。如图15.4a示，这些锯和手工锯工作是一样的：向前的行程进行切削，为了返回行程不拖行返回时稍稍抬起。电动钢锯的尺寸是他能切削的最大的毛坯件的横截面积。6X6英寸是一种典型的尺寸。所用的电动机不一样，动力1-10马力不等。图 15.4b: 用于高生产率的自动电锯.(Courtesy: Kasto-Racine, Inc.)这些锯的速度是每分钟锯的行程。重锯在难加工的材料时加工次数时大量减少，每分钟30次，加工碳钢和有色金属时能高达每分钟165次。钢锯一般有四到六个不同的速度。 每个行程正向进给，进给量用摩擦和压力驱动。小型的电锯每个行程进给量大概0.006英寸，大一点的每个行程进给量0.012到0.030。作用在刀具的上的进给压力为450到750英镑。工件装夹在手动或电动的内置虎钳上。如图15.4b所示自动电锯将用预置计和限位开关来进给预定的长度，装夹虎钳，切断，为下一次切削提升锯。这些切削可以精确到0.010英寸或者更精确。当然这些是非常昂贵的，因此在大量工作需要完成时才被使用。15.4.2 带锯切削带锯切削是使用以无限循环的形式进行的连续的直线运动。带锯使用了一种类似于轮滑一样的驱动原理使其连续运动，引导着锯从工件中通过。带锯分为立式和卧式两种。这指的是切削时锯的运动方向。立式带锯用作切断或者其他像加工轮廓和切槽这样的操作。卧式带锯一般作为电锯的代替品用于切断工序。立式带锯: 无论轻的、中型的、或者重型的所有的立式带锯都是由特定的基本的零件组成。即使这些机器的主要零件是由不同的方法制成，对于加工者来说，他们的基本功能都是一样的。如图15.5a示是一台典型的立式带锯。图 15.5a:典型立式锯床(Courtesy: Clausing Industries，Inc.)立式带锯从手动进给的轻型机械到拥有动力进给的重型机械的尺寸和配置都适用。轻型机械一般有两个轮，且这两轮通过变速带驱动装置如v带和塔轮驱动，或者其他一些形式的变速原理驱动。用在轻型机械上的刀片宽度从3/16英寸到5/8英寸变化。工作台类型:立式金属切削带锯的工作台一般用铸铁制作且运用了倾斜原理以至于可以切削简单或者复杂的角度。在固定工作台机床上工作台不能随着工件移动，但是在大部分机床上能够向右倾斜45度或者向左倾斜10度。工件能够手动的进给和引导或者依靠重力驱动。 装有动力驱动的工作台的立式带锯一般是重型机械。由工作台移动提供进给压力；操作者可以改变进给速率。轻型机械上有充足的动力使高速钢和碳化钨锯片比高碳钢锯片能更有效地利用。冷却系统广泛应用于动力驱动工作台机械，这样允许在锯片较长的寿命里有更高的切削速度和更高的进给速率。许多固定方式用于动力驱动工作台机械，特别用他们来重复操作。如图15.5b所示拥有高生产率的自动工作台机床。图 15.5b: 高生产自动立式带锯工作台机床(Courtesy: Clausing Industries，Inc.)附件:大部分没有冷却系统的带锯有一个气泵,这个气泵在锯片锯削的部位放出一股气流。这气流吹掉切屑，使操作者能够清楚的看见布局线的同时起了冷却作用。如果机床有液体冷却系统，油箱和泵则安装在底座上。一个分离的开关控制这个泵。冷却系统一般安装在中型和重型立式带锯。刀片焊接附件，是一种特殊的电焊机，几乎是所有的带锯上的都有的附件。刀片焊接一般由铜铸的夹具，砂轮，厚的锯，和必要的开关和操作杆组成。均衡在带锯上的进给设备的重量与动力驱动进给附件不相适应。这减少了操作者的疲劳而且能够得到均匀的进给率和更长的刀具寿命。 图 15.6a典型的卧式锯床(Courtesy: Clausing Industries，Inc.)其他像切削圆弧和圆的夹具，栏板，量具这样的附件也广泛应用于带锯之上。为在大批量生产应用而设计了的一些装夹特殊形式的工件夹具。卧式带锯：因为卧式带锯主要运用于切削棒料和型钢，也即是大家都知道的切断锯。切断带锯广泛被应用，因为他容易安装且有一个很窄的切口，这只要求很少的动力驱动且浪费很少的材料。切削时运动连续的而且很迅速。刀片安装在被切削材料的两边，如果机床能正确的调整且刀片拥有一个很好地工作条件，切削就精确。一个典型的卧式带锯如图15.6a所示。卧式带锯范围很广，从图15.6a所示的很小的动力的机械到图15.6b所示的很大的重型工业锯。图15.6b: 大中型工业卧式带锯(Courtesy: Armstrong-Blum Mfg. Co.)锯的导轨是精确切断工序中是很重要的因素。惰轮和导轨使锯片沿着垂直于被切削材料的方向做螺旋运动。碳化钨嵌入物能帮助减少磨损。图15.7显示了更先进的拥有自动工作台材料进给系统的卧式带锯。图 15.7: 材料进给自动工作台卧式带锯 (Courtesy: Kasto-Racine, Inc.)控制器和配件：在轻型锯中控制很简单，主要由一个主要开关和一个进给压力控制器组成。大型机械的控制面板一般安装在锯的一头。它是由必要的开关、阀、指示锯片进给速度（ 英尺/每分钟）、进给速率（ 英寸/每分钟）的设备，还有其他类似锯片张紧度的因素的设备组成。一些用于产品生产的机床能够全自动运行，能够预先决定切削给定数量的零件。计数器通常是自动和半自动机械仪表一部分。冷却系统几乎都安装在中型和大型的卧式带锯上。冷却系统能延长刀具寿命，允许更高的切削速度，金属去除速率。操作者控制着冷却液流的速率。像蜡和油脂一样的固体润滑剂也同样被应用。一棒状形式的蜡经常人工的应用于轻型的机床。15.4.3钢锯和带锯的比较习惯左右着一些决定如应该买什么形式的锯。然而，这里有一些应该考虑的确定的因素。成本：钢锯要相对便宜些，价格经常只有相同型号的电锯的一半。 锯片：钢锯的锯片的花费只有带锯锯片花费的1/4到1/2。然而，钢锯只能加工带锯能加工数的1/4到1/2工件就变钝。钢锯一般不被破坏，在加工硬质材料时不太容易折断齿。切痕：带锯比钢锯薄，特别是大型的更是如此。这导致在切削时浪费材料很少。然而，这种节省随着棒料用完时有2到6英寸的头被扔掉而消失了。速度：带锯切断材料时速度是钢锯切断时的两倍。然而，更多的把精力和时间花费在更换带锯或者调整锯削方向和速度。因此，经验不丰富的操作者经常使用带锯。April 2002/Tooling & Production 12 Tooling & Production/April 2002George Schneider, Jr. CMfgEProfessor EmeritusEngineering TechnologyLawrence Technological UniversityFormer ChairmanDetroit Chapter ONESociety of Manufacturing EngineersFormer PresidentInternational Excutive BoardSociety of Carbide & Tool EngineersLawrence Tech.- Prentice Hall- ?15.2 SawingSawing is a process where a nar-row slit is cut into the workpiece by atool consisting of a series of nar-rowly spaced teeth called a sawblade. Sawing is normally used toseparate work parts into two or morepieces or to cut off an unwantedsection of a part. These processes areoften called cut-off operations andsince many manufacturing projectsrequire cut-off operations at somepoint of the production sequence,sawing is an important manufactur-ing process.Sawing is basically a simple pro-cess. As the blade moves past the work,each tooth takes a cut. Depending onthe thickness or diameter of the work,the number of teeth cutting at one timevaries from 2 to 10 or more. Saws maybe of the continuous cutting (band orrotary) or reciprocating type. A typicalsawing operation is shown in Figure15.1.The cutting speeds and characteris-tics of the materials must be under-stood before the proper blades andoperating conditions can be selected.Saws are an effective and efficientcategory of machine tools found inalmost every type of machine shop.15.3 Saw BladesAll saw blades have certain commoncharacteristics and terminology. Someof these terms are shown in Figure15.2, and others are explained below.Rake Angles: Rake angles are 0degrees or neutral rake on most sawblades. Some have a positive rakeangle as shown in Figure 15.2a.Width: The width of a saw blade isits total width including the teeth.Set: The set of a saw blade meansthe offsetting of some teeth so that theMetal RemovalCutting-Tool MaterialsMetal Removal MethodsMachinability of MetalsSingle Point MachiningTurning Tools and OperationsTurning Methods and MachinesGrooving and ThreadingShaping and PlaningHole Making ProcessesDrills and Drilling OperationsDrilling Methods and MachinesBoring Operations and MachinesReaming and TappingMulti Point MachiningMilling Cutters and OperationsMilling Methods and MachinesBroaches and BroachingSaws and SawingAbrasive ProcessesGrinding Wheels and OperationsGrinding Methods and MachinesLapping and HoningUpcoming ChaptersFIGURE 15.1: Typical sawing operation.(Courtesy: Clausing Industries, Inc.15.1 IntroductionOnce sawing was considered a secondary machining process and saws were usedmostly for cutting bar stock in preparation for other machining operations. Inrecent years, the development of new types of saws and better blade materialshave made metal sawing a much more effective, versatile and economicalprocess. In many cases bandsaws are now being used as the primary means ofshaping certain types of metal parts.When the proper sawing machines and blades are used, sawing is one of themost economical means of cutting metal. The saw cut (kerf) is narrow, andrelatively few chips are produced in making a cut. When a bandsaw is used forcutting the contours of complex shapes, only a small portion of the metal isremoved in the form of chips. Therefore, the power used in removing largeamounts of waste metal is at a minimum.2 Tooling & Production/Chapter 15Chapter 15/Tooling & Production 3Chap. 15: Saws and SawingChap. 15: Saws and Sawingback of the blade clears the cut. Theraker set is most frequently used andis furnished with all hacksaws andband saws unless otherwise specified.(See Fig. 15.2b)Kerf: The kerf is the width of thecut made by the saw blade or thematerial cut away. The thickness of theblade is called the gage.Pitch: The pitch of a saw blade isthe distance between the tops of twoadjacent teeth. This is specified inteeth per inch.15.3.1 Saw Blade MaterialSaw blades are made from variousmaterials as explained below:Carbon Steel: General utility forsmall lot, low speed work. The leastexpensive blade, these may have a hardback for greater wear.High Speed Steel: This costs two tothree times as much as carbon steel,but it is much longer wearing and is anecessity for the difficult-to-machinemetals.High Speed Edge: This is a carbonsteel blade, which has a narrow stripwith HSS teeth welded on. This is atough blade, intermediately priced, andwidely used for most materials.Tungsten Carbide Tipped Blades:Available in a few sizes. Used only onlarge, very rigid sawing machines forhigh production sawing of difficultmaterials.15.3.2 Saw Blade SelectionThe process of choosing the bestbandsaw blade for a particular jobmust start with an evaluation of thematerial to be cut. Such factors ashardness, machinability, cross-sec-tional shape and area must be consid-ered.After the material to be cut has beenproperly identified, the selector on themachine can be used to help select theproper bladeand cuttingspeed, Tablesand selectorsare helpful,but the opera-tor often mustmake choicesthat affect thethree variablespresent in ev-ery sawing op-eration: cutting rate, tool life, and ac-curacy. Generally, increasing any onevariable results in a decrease in one orboth of the others. For example, anincrease in cutting rate always reducestool life and may affect accuracy,15.3.3 Saw Blade WeldingPractically all vertical metal-cuttingband-saws have an attachment forelectrically butt-welding blades. It isusually set on the column of the ma-chine at the operators left and consistof a blade cutter, a small grindingwheel, and the butt welding machine.The blade welding attachment can beused for making saw bands from bulksaw-blade stock or for welding bandsthat have been cut and inserted into ahole in a workpiece that is to be band-sawed internally.The importance of making goodwelds in saw blades couldnt be over-emphasized. Breakage caused by poorwelding, improper joint finishing, orimproper heat treatment is time con-suming and potentially dangerous.Butt Welder: The resistance-typebutt welders found on almost all verti-cal bandsaws operate by causing elec-trical current to flow through the endsof the bandsaw blade while pressure isbeing applied. The high resistancewhere the blade ends meet causes themetal to become white-hot momen-tarily, and the blade ends fuse. Provi-sion is made for annealing (softening)the welded joint. As the operatorpresses the anneal button for a veryshort time, current flows through thecompleted joint until the joint heats toa dull red. The joint then anneals as itcools slowly.15.4 Sawing EquipmentIn most sawing operations, the workis held stationary and the saw blade ismoved relative to it. As shown in Fig-ure 15.3, there are three basic types ofsawing operations, according to thesaw blade motion involved:15.4.1 HacksawingHacksawing involves a linear recip-rocating motion of the saw against theworkpiece. This method of sawing isoften used in cut-off operations. Cut-ting only takes place on the forwardstroke of the saw blade. Due to thisintermittent cutting action,hacksawing is less efficient than othersawing methods. Hacksawing can beTooth backclearance angleToothback(flank)ToothfaceTooth rakeangle (positive)Gullet depthBack edgeWidthToothspacingStraight toothRaker toothWave toothToothset(a)(b)Hydraulic or gravity pressure WorkviseCutting DirectionCutting directionReciprocating Blade HacksawEccentricdriveHydraulic orgravity pressureWork viseContinuous Band Cutoff SawBlade guidesHinge point(a)(c)Blade guideWork tableResistanceblade welderDrive wheel(b)FIGURE 15.2: Saw blade characteristics and terminology.FIGURE 15.3: Three basic types of sawing operations: (a) hacksawing, (b) verticalbandsawing, (c) horizontal bandsawing.4 Tooling & Production/Chapter 15Chap. 15: Saws and Sawingdone manually or with a power hack-saw. A power hacksaw provides a drivemechanism to operate the saw blade ata desired speed and feed rate. (Fig.15.3a)Power Hacksaw: The power hack-saw is the original and least expensivesaw for the work. As shown in Figure15.4a, these saws work the same as ahand hacksaw: They cut on the forwardstroke and then lift slightly so that theblade does not drag on the returnstroke.The size of a power hacksaw is thecross section of the largest piece ofstock that it can cut. Typical sizes are 6x 6 inches to 24 x 24 inches. Themotors used will vary from 1 to 10horsepower.The speed of these saws is in strokesper minute. This may be from 30strokes per minute for large cuts withheavy saws on difficult materials, up to165 strokes per minute on carbonsteels and nonferrousmaterials. The hacksawusually has four to sixdifferent speeds avail-able.Feed may be a posi-tive advance per strokeor may be gaged by afriction or pressuredrive. The smallerpower hacksaws feedabout 0.006 inches perstroke and the largerones 0.012 to 0.030inches per stroke. Feedpressures will be 450 to750 pounds on theblades. Work is held ina built-in vise, whichmay be hand or power operated.Automatic power hacksaws (Fig.15.4b) will feed the stock a presetlength, clamp the vise, cut off, andraise the saw for the next cut, all withpreset gages and limit switches. Thesewill cut accurate lengths to within0.010 inches or less. They are, ofcourse, expensive and so they would beused only if a large amount of work isto be done.15.4.2 BandsawingBandsawing involves a linear con-tinuous motion, using a bandsaw blademade in the form of an endless loop.The band saw provides a pulley-likedrive mechanism to continuously moveand guide the bandsaw blade past thework. Bandsaws are classified as verti-cal or horizontal. This designation re-fers to the direction of saw blade mo-tion during cutting. Vertical bandsawsare used for cut-off and other opera-tions such as contouring and slotting.Horizontal bandsaws are normallyused for cut-off operations as alterna-tives to power hacksaws. (Fig. 15.3band Fig. 15.3c)Vertical Bandsaws: All verticalbandsaws, regardless of whether theyare light, mediums, or heavy-duty ma-chines, are made up of certain basiccomponents. Although these majorparts of the machine may be made bydifferent methods, depending on themanufacturer, their function is essen-tially the same. A typical verticalbandsaw is shown in Figure 15.5a.Vertical bandsaws are available insizes and configurations ranging fromlight-duty hand-fed machines toheavy-duty machines with power feedtables. The light-duty machines usu-ally have two wheels and are driventhrough a variable speed belt drive, Vbelts and step pulleys, or some othertype of speed change mechanism.Blades ranging from 3/16 inch to 5/8inch in width can be used on light-dutymachines.Table Types: The table of the verti-cal metal cutting bandsaw is usuallymade of cast iron and fitted with atilting mechanism so that simple orcompound angle cuts can be made. Onfixed-table machines, the table does notmove with the work, but can be tilted 45degrees to the right and 10 degrees tothe left on most machines. The workcan be fed and guided manually, or aweight operated feed mechanism can beused to supply the feed pressure.FIGURE 15.5a: Typical vertical band-saw. (Courtesy: Clausing Industries,Inc.)Chap. 15: Saws and SawingFIGURE 15.5b: High-production auto-mated vertical bandsaw table machine.(Courtesy: Armstrong-Blum Mfg. Co.)FIGURE 15.4a: Semiautomatic power hacksaw.FIGURE 15.4b: Automatic power hack-saw used in high-production sawing.(Courtesy: Kasto-Racine, Inc.)Chapter 15/Tooling & Production 5Chap. 15: Saws and SawingVertical bandsaws with power tablesare generally heavy-duty machines.The feed pressure is provided by themechanism that moves the table; theoperator can vary the feed rate.There is usually enough power avail-able to make effective use of high-speed steel or tungsten carbide sawblades rather than the high carbon steelblades used on light-duty machines.Coolant systems are also widely usedon power table machines, thus allow-ing higher cutting speeds and higherfeed rates along with longer blade life.Many types of fixtures can be used onpower table machines, particularlywhen they are used for repetitive op-erations. A high production automatedtable machine is shown in Figure15.5b.Accessories: Most bandsaws that donot have a coolant system have an airpump that directs a stream of air at thepoint where the blade is cutting theworkpiece. This removes the chips,letting the operator see the layout linesclearly, and provides some cooling.If the machine has a fluid coolantsystem, the tank and pump are usuallylocated in the base. A separate switchcontrols the pump. Coolant systemsare usually found on medium andheavy duty vertical bandsaws.Blade welding attachments, whichare a specialized form of electricbutt-welding machines, are a stan-dard accessory on almost allbandsaws. The blade welder usuallyconsists of cast copper or bronzeblade clamps, a grinder, a saw thick-ness gage, and the necessaryswitches and operating levers.Weight operated feed devices can beused on bandsaws not fitted withpower feed attachments. This reducesoperator fatigue and generally resultsin more uniformfeed rates andlonger blade life.Other attach-ments such as fix-tures for cuttingarcs and circles,ripping fences, andmiters, are used ex-tensively onbandsaws. Specialfixtures for holdingspecific types ofworkpieces are of-ten designed for usein mass productionapplications.Horizontal Bandsaws: Becausehorizontal bandsaws are used primarilyfor cutting bar stock and structuralshapes, they are also known as cut-offsaws. The band-type cut-off saw iswidely used because it is easy to set upand takes a narrow saw cut, thus re-quiring less power to operate and wast-ing less material. The cutting action iscontinuous and rapid. The blade issupported close to either side of thematerial being cut, so the cut is accu-rate if the machine is properly adjustedand the blade is in good condition. Atypical horizontal bandsaw is shown inFigure 15.6a.Horizontal bandsaws range in ca-pacity from small, fractional horse-power machines, (Fig. 15.6a), to largeheavy-duty industrial saws, as shownin Figure 15.6b.The saw guides are an importantfactor in accurate cut-off operations.The saw blade has to twist as it leavesthe idler pulley and the guides makethe blade travel perpendicular to thematerial being cut. Tungsten carbideinserts help minimize wear. Figure15.7 shows a more advanced horizon-FIGURE 15.6a: Typical horizontalbandsaw. (Courtesy: Clausing Indus-tries, Inc.)FIGURE 15.5b: Large, heavy-duty industrialhorizontal bandsaw. (Courtesy: Armstrong-Blum Mfg. Co.)FIGURE 15.7: Horizontal Band Saw with automated tablestock feeding system (Courtesy: Kasto-Racine, Inc.)tal band saw with an automated tablestock feeding system.Controls and Accessories: On lightduty saws, the controls are simple,consisting mainly of an off-on switch,a means for changing blade speed, andpossibly a control for feed pressure. Onthe larger machines a control panel isusually mounted on the saw head. Itconsists of the necessary switches,valves, and instruments that indicateblade speed in feet per minute, feedrate in inches per minute, and otherfactors, such as blade tension. Somemachines used for production work arecapable of fully automatic operationand can be preset to cut a given num-ber of pieces of work. A counter isusually part of the instrumentation onsemiautomatic and automatic ma-chines.There are coolant systems on almostall medium and heavy duty horizontalbandsaws. The coolant extends bladelife and allows higher cutting speedsand metal removal rates. The operatorcontrols the rate of coolant flow. Solidlubricants such as wax or grease canalso be used. Wax in stick form isusually applied manually to theblade on light-duty machines.15.4.3 Comparison ofHacksaws and Band SawsThe decision as to which typeof cut-off saw to buy is ofteninfluenced by custom or habit.However, there are definite fac-tors that can be considered.Cost: A hacksaw is much lessexpensive, often about half thecost of a band saw of equal sizeand power.Chap. 15: Saws and Sawing6 Tooling & Production/Chapter 15Chap. 15: Saws and SawingSaw blades: The hacksaw bladesmay cost one-half to one-quarter thecost of a band-saw blade. However, thehacksaw will become dull in one-halfto one-quarter the number of cuts thatthe band saw will make.The hacksaw blade is almost un-breakable and is somewhat less likelyto have its teeth stripped off by hardspots in the material being cut.Kerf: The band-saw blade is thinnerthan the hacksaw blade, especially forthe larger sizes. Thus less metal iswasted in the cut. However, this sav-ing is often lost because of the 2 to 6inch long stub end, which is throwninto the scrap, bin when the bar ofstock is used up.Speed: The band saw will cut offstock up to twice as fast as the hack-saw. However, it does take more careand more time to change blades, adjustsaw guides, and regulate feeds. Thus,the plain hacksaw can be used by lessexperienced operators.15.5 Band Sawing OperationsThe types of work described hereaccounts for most of the band sawingoperations used in metalworking.15.5.1 Cut-off SawingAlthough cut-off sawing can bedone on any type of vertical or hori-zontal bandsaw, the majority of cut-offsawing is done onpowerful horizontalmachines. A varietyof work-holdingdevices and fix-tures can be used tohold tubing, angleiron, and othershapes.Blade selectionis important interms of economyand the finish onthe material beingcut. The precisiontooth type blade isused extensivelywith the recommended pitch rangingfrom 10 teeth per inch for sections upto 3/8 in. thickness to 4 teeth per inchfor material over 3 in. thick. Manufac-turers manuals should be consultedwhen heavy cuts are being attempted.The claw tooth type of blade is usedwhen cutting some tough steels be-cause the tooth penetrates the surfaceof the work more easily.Stock feeders are often used on cut-off machines, along with an indexingmechanism that allows the operator toautomatically repeat cuts of pre-se-lected lengths. Almost all cut-off op-erations are done with a liquid coolantdelivered to the saw cut by a pump.15.5.2 Contour SawingContour sawing, both internal andexternal, is one of the most versatileoperations that can be done with abandsaw. It may range from simpleshapes cut on a fractional horsepowermachine to complex internal cutsmade with tilting table machines.Blade selection is important when cut-ting complex contours, especiallywhen small radii or corners are in-volved. Select the widest blade thatwill allow turns of the proper radius.For internal work, a hole must bedrilled so that the blade can be passedthrough it and re-welded. For plaincontouring, the hole is drilled perpen-dicular to the face of the workpiece.When the internal shape has corners,holes must be drilled at the corners sothat the blade can be turned and the cutstarted in another direction.15.5.3. Friction SawingFriction sawing is a unique process.A bandsaw blade with dull teeth travel-ing at very high speed, 6000 to 15000SFPM (surface feet per minute), isused to cut both hard and soft ferrousmetals. Friction sawing works particu-larly well on metals that have poor heatconductivity because the heat-affectedzone remains very small. It is thefastest method of cutting ferrous met-als less than 1 in. thick.As the blade contacts the work, themetal at the point of contact immedi-ately becomes white hot and is carriedout by the teeth. The blade itself re-mains relatively cool because duringits operating cycle it is in contact withhot metal for only a short time.FIGURE 15.8: Semi-automatic CircularSaw (Courtesy: Clausing Industries, Inc.)FIGURE 15.9: Automated Band Saw with computer-controlledfunctions (Courtesy: Kasto-Racine. Inc.)FIGURE 15.10: Typical cold saw.(Courtesy: Clausing Industries, Inc.)Chap. 15: Saws and SawingChapter 15/Tooling & Production 7Chap. 15: Saws and Sawing15.
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