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机械加工工艺过程卡片产品型号零件图号01产品名称变速箱盖零件名称变速箱盖共1页第1页材 料 牌 号HT200毛 坯 种 类铸件毛坯外形尺寸每毛坯件数1每 台 件 数1备 注 工 序 号 工 名 序 称 工 序 内 容车间 工 段设 备工 艺 装 备 工 时 夹具刀具量具 准终 单件10铸造铸造铸20时效时效热30涂底漆涂底漆漆40粗铣粗铣底部大端面 机加工二X52K铣床铣夹具铣刀游标卡尺50精铣精铣底部大端面机加工二X52K铣床铣夹具铣刀游标卡尺60粗铣粗铣顶部平面机加工二X52K铣床铣夹具铣刀游标卡尺70精铣精铣顶部平面 机加工二X52K铣床铣夹具铣刀游标卡尺80钻钻8-12孔机加工二钻床Z525专用钻夹具莫氏锥柄长刃机用钻头游标卡尺90去毛刺去毛刺100检查检查 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XX学院变速箱盖零件工艺及其平面铣夹具设计学生姓名 学 号 专 业 班 级 指导教师 25摘 要变速箱盖零件加工工艺及夹具设计是包括零件加工的工艺设计、工序设计以及专用夹具的设计三部分。在工艺设计中要首先对零件进行分析，了解零件的工艺再设计出毛坯的结构，并选择好零件的加工基准，设计出零件的工艺路线；接着对零件各个工步的工序进行尺寸计算，关键是决定出各个工序的工艺装备及切削用量；然后进行专用夹具的设计，选择设计出夹具的各个组成部件，如定位元件、夹紧元件、引导元件、夹具体与机床的连接部件以及其它部件；计算出夹具定位时产生的定位误差，分析夹具结构的合理性与不足之处，并在以后设计中注意改进。关键词：工艺，工序，切削用量，夹紧，定位，误差AbstractAutomobile gearbox cover parts processing and fixture design process design, including machining process design and fixture three. In process design should first of all parts for analysis, to understand part of the process to design blank structure, and choose the good parts machining datum, design the process routes of the parts; then the parts of each step in the process to the size calculation, the key is to determine the craft equipment and the cutting dosage of each working procedure design; then the special fixture, the fixture for the various components of the design, such as the connecting part positioning devices, clamping element, a guide element, fixture and machine tools and other components; positioning error calculated by the analysis of fixture, jig structure the rationality and the deficiency, pay attention to improving and will design in.Keywords: process, process, cutting dosage, clamping, positioning目 录摘 要II目 录IV第1章 序 言1第2章 零件的分析22.1零件的形状22.2零件的工艺分析2第3章 工艺规程设计43.1 确定毛坯的制造形式43.2 基面的选择43.3 制定工艺路线43.3.1 工艺路线方案一53.3.2 工艺路线方案二53.3.3 工艺方案的比较与分析53.4 选择加工设备和工艺装备63.4.1 机床选用63.4.2 选择刀具63.4.3 选择量具73.5 机械加工余量、工序尺寸及毛坯尺寸的确定73.6确定切削用量及基本工时8第4章 变速箱盖平面铣夹具设计134.1 研究原始质料134.2 定位、夹紧方案的选择144.3 切削力及夹紧力的计算144.3.1 气缸的直径确定174.3.2 气缸的选型184.4 误差分析与计算194.5 确定夹具体结构和总体结构204.6夹具设计及操作的简要说明22总 结23参 考 文 献24致谢25 第1章 序 言机械制造业是制造具有一定形状位置和尺寸的零件和产品，并把它们装备成机械装备的行业。机械制造业的产品既可以直接供人们使用，也可以为其它行业的生产提供装备，社会上有着各种各样的机械或机械制造业的产品。我们的生活离不开制造业，因此制造业是国民经济发展的重要行业，是一个国家或地区发展的重要基础及有力支柱。从某中意义上讲，机械制造水平的高低是衡量一个国家国民经济综合实力和科学技术水平的重要指标。变速箱盖零件加工工艺及夹具设计是在学完了机械制图、机械制造技术基础、机械设计、机械工程材料等的基础下，进行的一个全面的考核。正确地解决一个零件在加工中的定位，夹紧以及工艺路线安排，工艺尺寸确定等问题，并设计出专用夹具，保证尺寸证零件的加工质量。本次设计也要培养自己的自学与创新能力。因此本次设计综合性和实践性强、涉及知识面广。所以在设计中既要注意基本概念、基本理论，又要注意生产实践的需要，只有将各种理论与生产实践相结合，才能很好的完成本次设计。本次设计水平有限，其中难免有缺点错误，敬请老师们批评指正。第2章 零件的分析2.1零件的形状题目给的零件是变速箱盖零件，主要作用是起连接作用。零件的实际形状如上图所示，从零件图上看，该零件是典型的零件，结构比较简单。具体尺寸，公差如下图所示。图2-1 变速箱图2.2零件的工艺分析由零件图可知，其材料为HT200，该材料为灰铸造，具有较高强度，耐磨性，耐热性及减振性，适用于承受较大应力和要求耐磨零件。变速箱盖零件主要加工表面为：1. 粗铣底面、半精铣，表面粗糙度值为3.2。2. 粗铣、半精铣上端面，表面粗糙度值3.2。变速箱盖共有两组加工表面，他们之间有一定的位置要求。现分述如下：(1)底部端面的加工表面： 这一组加工表面包括：端面，内圆，倒角钻孔并攻丝。这一部份只有端面有6.3的粗糙度要求。其要求并不高，粗车后半精车就可以达到精度要求。而钻工没有精度要求，因此一道工序就可以达到要求，并不需要扩孔、铰孔等工序。(2).顶面的加工表面： 这一组加工表面包括：顶面的粗糙度为3.2 第3章 工艺规程设计本变速箱盖假设年产量为10万台，每台车床需要该零件1个，备品率为19%，废品率为0.25%，每日工作班次为2班。该零件材料为HT200，考虑到零件在工作时要有高的耐磨性，所以选择铸铁铸造。依据设计要求Q=100000件/年，n=1件/台；结合生产实际，备品率和 废品率分别取19%和0.25%代入公式得该工件的生产纲领 N=2XQn(1+)（1+)=238595件/年3.1 确定毛坯的制造形式零件材料为HT200，铸件的特点是液态成形，其主要优点是适应性强，即适用于不同重量、不同壁厚的铸件，也适用于不同的金属，还特别适应制造形状复杂的铸件。考虑到零件在使用过程中起连接作用，分析其在工作过程中所受载荷，最后选用铸件，以便使金属纤维尽量不被切断，保证零件工作可靠。年产量已达成批生产水平，而且零件轮廓尺寸不大，可以采用砂型铸造，这从提高生产效率，保证加工精度，减少生产成本上考虑，也是应该的。3.2 基面的选择基面选择是工艺规程设计中的重要工作之一，基面选择的正确与合理，可以使加工质量得到保证，生产效率得以提高。否则，不但使加工工艺过程中的问题百出，更有甚者，还会造成零件大批报废，使生产无法正常进行。粗基准的选择，对像变速箱盖这样的零件来说，选好粗基准是至关重要的。对本零件来说，如果外圆的端面做基准，则可能造成这一组内外圆的面与零件的外形不对称，按照有关粗基准的选择原则(即当零件有不加工表面时，应以这些不加工表面做粗基准，若零件有若干个不加工表面时，则应以与加工表面要求相对应位置精度较高的不加工表面做为粗基准)。对于精基准而言，主要应该考虑基准重合的问题，当设计基准与工序基准不重合时，应该进行尺寸换算，这在以后还要专门计算，此处不在重复。3.3 制定工艺路线制定工艺路线的出发点，应当是使零件的几何形状、尺寸精度及位置精度等技术要求能得到合理的保证。在生产纲领已经确定为成批生产的条件下，可以考虑采用万能性机床配以专用夹具，并尽量使工序集中来提高生产率。除此以外，还应当考虑经济效果，以便使生产成本尽量下降。3.3.1 工艺路线方案一10铸造铸造20时效时效30涂底漆涂底漆40粗铣粗铣底部大端面 50精铣精铣底部大端面60粗铣粗铣顶部平面70精铣精铣顶部平面 80钻钻8-12孔90去毛刺去毛刺100检查检查3.3.2 工艺路线方案二10铸造铸造20时效时效30涂底漆涂底漆40粗铣粗铣底部大端面 50精铣精铣底部大端面60粗车粗车顶部平面70精车精车顶部平面 80钻钻8-12孔90去毛刺去毛刺100检查检查3.3.3 工艺方案的比较与分析上述两个方案的特点在于：方案一的定位和装夹等都比较方便。方案二采用镗床加工，需要要及时更换刀具，因为有些工序在车床上也可以加工，镗、钻孔等等，需要换上相应的刀具。因此综合工艺方案，取优弃劣，具体工艺过程如下：10铸造铸造20时效时效30涂底漆涂底漆40粗铣粗铣底部大端面 50精铣精铣底部大端面60粗铣粗铣顶部平面70精铣精铣顶部平面 80钻钻8-12孔90去毛刺去毛刺100检查检查3.4 选择加工设备和工艺装备3.4.1 机床选用.工序是粗铣、和精铣。各工序的工步数不多，成批量生产，故选用铣床就能满足要求。本零件外轮廓尺寸不大，精度要求属于中等要求，选用最常用的X52K铣床。参考根据机械制造设计工工艺简明手册表4.2-7。.工序是钻孔，选用Z525摇臂钻床。3.4.2 选择刀具.在铣床上加工的工序,一般选用硬质合金铣刀。加工刀具选用YG6类硬质合金车刀，它的主要应用范围为普通铸铁、冷硬铸铁、高温合金的精加工和半精加工。为提高生产率及经济性,可选用可转位铣刀(GB5343.1-85,GB5343.2-85)。.钻孔时选用高速钢麻花钻，参考机械加工工艺手册（主编 孟少农），第二卷表10.21-47及表10.2-53可得到所有参数。3.4.3 选择量具本零件属于成批量生产，一般均采用通常量具。选择量具的方法有两种：一是按计量器具的不确定度选择；二是按计量器的测量方法极限误差选择。采用其中的一种方法即可。3.5 机械加工余量、工序尺寸及毛坯尺寸的确定“变速箱盖” 零件材料为HT200，查机械加工工艺手册（以后简称工艺手册），表2.2-17 各种铸铁的性能比较，灰铸造的硬度HB为143269，表2.2-23 灰铸造的物理性能，HT200密度=7.27.3（），计算零件毛坯的重量约为2。表3-1 机械加工车间的生产性质生产类别同类零件的年产量件重型（零件重2000kg）中型（零件重1002000kg）轻型（零件重100kg）单件生产5以下10以下100以下小批生产510010200100500中批生产1003002005005005000大批生产30010005005000500050000大量生产1000以上5000以上50000以上根据所发的任务书上的数据，该零件的月工序数不低于3050，毛坯重量21202506.04.0顶、侧面底 面铸孔的机械加工余量一般按浇注时位置处于顶面的机械加工余量选择。根据上述原始资料及加工工艺，分别确定各加工表面的机械加工余量、工序尺寸及毛坯尺寸。3.6确定切削用量及基本工时切削用量一般包括切削深度、进给量及切削速度三项。确定方法是先是确定切削深度、进给量，再确定切削速度。现根据切削用量简明手册（第三版，艾兴、肖诗纲编，1993年机械工业出版社出版）确定本零件各工序的切削用量所选用的表格均加以*号，与机械制造设计工工艺简明手册的表区别。工序10、20、30：铸造 时效处理无切削加工，无需计算工序40、50：粗铣、精铣底部大端面机床：铣床X52K刀具：面铣刀(硬质合金材料)，材料：， ，齿数。单边余量：Z=3mm所以铣削深度：精铣面余量：Z=1.0mm铣削深度：每齿进给量：取：取铣削速度每齿进给量：取取铣削速度机床主轴转速：按照文献，取 实际铣削速度： 进给量： 工作台每分进给量： ：,取切削工时被切削层：由毛坯可知， 刀具切入： 刀具切出：取走刀次数为1机动时间： 机动时间：所以该工序总机动时间工序60、70：粗铣、精铣顶部平面机床：铣床X52K刀具：面铣刀(硬质合金材料)，材料：， ，齿数。单边余量：Z=3mm所以铣削深度：精铣面余量：Z=1.0mm铣削深度：每齿进给量：取：取铣削速度每齿进给量：取，取铣削速度机床主轴转速：按照文献，取 实际铣削速度： 进给量： 工作台每分进给量： ：取切削工时被切削层：由毛坯可知， 刀具切入： 刀具切出：取走刀次数为1机动时间： 机动时间：所以该工序总机动时间工序80：钻扩底部8-12孔机床：立式钻床Z525刀具：根据选高速钢锥柄麻花钻头。 钻孔钻孔时先钻孔。切削深度：进给量：取。切削速度取。机床主轴转速：，按照文献，取所以实际切削速度：切削工时 被切削层：刀具切入： 刀具切出： 取走刀次数为1机动时间： 铰孔12刀具：选择扩孔钻头（硬质合金锥柄麻花材料）。片型号：E403切削深度：进给量：取。切削速度：取。机床主轴转速：按照文献取所以实际切削速度：切削工时被切削层：刀具切入有：刀具切出： ，取走刀次数为1机动时间：第4章 变速箱盖平面铣夹具设计4.1 研究原始质料利用本夹具主要用来加工柱销孔，加工时除了要满足粗糙度要求外，还应满足两孔轴线间公差要求。为了保证技术要求，最关键是找到定位基准。同时，应考虑如何提高劳动生产率和降低劳动强度。一、机床夹具定位元件工件定位方式不同，夹具定位元件的结构形式也不同，这里只介绍几种常用的基本定位元件。实际生产中使用的定位元件都是这些基本定位元件的组合。（一）工件以平面定位常用定位元件1支承钉 常用支承钉的结构形式如图6-1所示。平头支承钉（图a）用于支承精基准面；球头支承钉（图b）用于支承粗基准面；网纹顶面支承钉（图c）能产生较大的摩擦力，但网槽中的切屑不易清除，常用在工件以粗基准定位且要求产生较大摩擦力的侧面定位场合。一个支承钉相当于一个支承点，限制一个自由度；在一个平面内，两个支承钉限制二个自由度；不在同一直线上的三个支承钉限制三个自由度。图6-1 常用支承钉的结构形式2支承板 常用的支承板结构形式如图6-2所示。平面型支承板（图a）结构简单，但沉头螺钉处清理切屑比较困难，适于作侧面和顶面定位；带斜槽型支承板（图b），在带有螺钉孔的斜槽中允许容纳少许切屑，适于作底面定位。当工件定位平面较大时，常用几块支承板组合成一个平面。一个支承板相当于两个支承点，限制两个自由度；两个（或多个）支承板组合，相当于一个平面，可以限制三个自由度。图6-2 常用支承板的结构形式3可调支承 常用可调支承结构形式如图6-3所示。可调支承多用于支承工件的粗基准面，支承高度可以根据需要进行调整，调整到位后用螺母锁紧。一个可调支承限制一个自由度。图6-3 常用可调支承的结构形式 (二) 工件以孔定位常用定位元件1定位销 图6-6是几种常用固定式定位销的结构形式。当工件的孔径尺寸较小时，可选用图 a 所示的结构；当孔径尺寸较大时，选用图 b 所示的结构；当工件同时以圆孔和端面组合定位时，则应选用图c所示的带有支承端面的结构。用定位销定位时，短圆柱销限制二个自由度；长圆柱销可以限制四个自由度；短圆锥销（图d）限制三个自由度。图6-6 固定式定位销的结构形式4.2 定位、夹紧方案的选择由零件图可知：在对加工前，平面进行了粗、精铣加工，底面进行了钻、扩加工。因此，定位、夹紧方案有：本夹具用于转盘式组合铣床上铣削汽车变速箱上盖的接合平面.转台上可安装三套同样的夹具.工件以格子面P安装在二个固定支承2上,限制三个自由度;以侧面S靠在两块固定支承板11上,限制两个自由度;又以端面R靠在一个固定支承1上,限制一个自由度,实现实例定位.为了防止工件在加工中发生变形,夹具上设置了辅助支承9,在原设计中还设置了两个辅助支承4,实践证明,两个辅助支承4可以不用(现已取消).夹紧时,操作气动换向阀12,使压缩空气推动活塞杆6,杠杆8和浮动压块7,从侧面将工件夹紧在固定支承板11上. 本图仍保留了原设计中的辅助支承4,目的是供初学者设计时参考,以便根据具体情况(如加工精度要求,毛坯件质量等)决定取舍.4.3 切削力及夹紧力的计算刀具：面铣刀（硬质合金） 刀具有关几何参数： 由参考文献55表129 可得铣削切削力的计算公式： 有：根据工件受力切削力、夹紧力的作用情况，找出在加工过程中对夹紧最不利的瞬间状态，按静力平衡原理计算出理论夹紧力。最后为保证夹紧可靠，再乘以安全系数作为实际所需夹紧力的数值，即： 安全系数K可按下式计算： 式中：为各种因素的安全系数，查参考文献5121可知其公式参数： 由此可得： 所以 气缸的选型计算：根据气缸推力拉力的大小要求，选定气缸使用压力参数以及缸径尺寸气缸推力计算公式：气缸推力F1=0.25D2P气缸拉力计算公式F2=0.25（D2-d2）P 公式式中：D-气缸活塞直径（cm） d-气缸活塞杆直径（cm） P-气缸的工作压力（kgf/cm2） F1，F2-气缸的理论推拉力（kgf）为了避免用户选用时的有关计算，下附双作用气缸输出力换算表，用户可根据负载、工作压力、动作方向从表格中选择合适的缸径尺寸双作用气缸输出力表单位Kgf缸径mm气缸的理论输出力（推力）单位：KG/公斤使用空气压力MPa0.8101.572.363.143.934.715.506.28164.026.038.0416.1206.289.4212.615.718.822.025.0259.8114.719.624.529.434.439.23216.048.356.364.44025.137.750.362.875.488.0100.5 5039.258.978.598.21171371576362.393.51251561872182508010015120125130035240210015723631439347155062812524536849161573685998216040260380410051206140716081805087631018127215271781203620062894212571571188521992514250981147319632454294534363926320160824123216402148255629643240025313796502662837539879610052 选定气缸的行程：确定工作的移动距离，考虑工况可选择满行程或预留行程。当行程超过推荐的最长行程时，要考虑活塞杆的刚度，可以选择支撑导向或选择特殊气缸。 选定气缸缓冲方式：根据需要选择缓冲形式，无缓冲气缸，固定缓冲气缸，可调缓冲气缸 选择润滑方式：有给油润滑气缸，无给油润滑气缸 选择气缸系列：根据以上条件，按需选择适当系列的气缸 选择气缸的安装形式：根据不同的用途和安装需要，选用适当的安装形式4.3.1 气缸的直径确定本气缸属于单向作用气缸。根据力平衡原理，单向作用气缸活塞杆上的输出推力必须克服弹簧的反作用力和活塞杆工作时的总阻力，其公式为:式中: - 活塞杆上的推力，N - 弹簧反作用力，N- 气缸工作时的总阻力，N- 气缸工作压力，Pa弹簧反作用按下式计算:Gf = 式中:- 弹簧刚度，N/m- 弹簧预压缩量，m- 活塞行程，m- 弹簧钢丝直径，m- 弹簧平均直径，.- 弹簧有效圈数.- 弹簧材料剪切模量，一般取在设计中，必须考虑负载率的影响，则:由以上分析得单向作用气缸的直径:代入有关数据，可得 所以:查有关手册圆整，得由,可得活塞杆直径:圆整后，取活塞杆直径校核，按公式有:其中，则:满足实际设计要求。4.3.2 气缸的选型经过比较，参考市场上的气缸类型，选择一种可靠优质的气缸产品的生产商速易可（上海）有限公司/about_us.asp。速易可气动（上海）有限公司成立于2004年，从事于空油压零组件和设备研 究、生产、销售的自动化厂商，产品以TONAB品牌营销国内外市场，产品主要有空气净化组件、气动控制组件、气动执行组件、辅助组件、空油压设备，产 品广泛应用于医疗器械、工业机器人、食品包装机械、纺织机械、半导体设备、轨道交通、烟草机械、机床自动控制、真空搬运、汽车制造、教学培训等行业。速易可目前主要产品有：无杆气缸、滑台气缸、止动气缸、回转气缸、机械夹、回转夹紧气（油）压缸、导杆气缸、带锁气缸、双轴缸、标准型气缸、控制阀、空气控制组件、真空系统组件及相关气动辅助零组件。根据上节计算，在这选择DEG32.4.4 误差分析与计算为了满足工序的加工要求，必须使工序中误差总和等于或小于该工序所规定的尺寸公差。与机床夹具有关的加工误差，一般可用下式表示： 由参考文献5可得：销的定位误差 ： 其中：， 夹紧误差 ： 其中接触变形位移值： 查5表1215有。 磨损造成的加工误差：通常不超过 夹具相对刀具位置误差：取误差总和：从以上的分析可见，所设计的夹具能满足零件的加工精度要求。4.5 确定夹具体结构和总体结构对夹具体的设计的基本要求（1）应该保持精度和稳定性在夹具体表面重要的面，如安装接触位置，安装表面的刀块夹紧安装特定的，足够的精度，之间的位置精度稳定夹具体，夹具体应该采用铸造，时效处理，退火等处理方式。（2）应具有足够的强度和刚度保证在加工过程中不因夹紧力，切削力等外力变形和振动是不允许的，夹具应有足够的厚度，刚度可以适当加固。（3）结构的方法和使用应该不错夹较大的工件的外观，更复杂的结构，之间的相互位置精度与每个表面的要求高，所以应特别注意结构的过程中，应处理的工件，夹具，维修方便。再满足功能性要求（刚度和强度）前提下，应能减小体积减轻重量，结构应该简单。（4）应便于铁屑去除在加工过程中，该铁屑将继续在夹在积累，如果不及时清除，切削热的积累会破坏夹具定位精度，铁屑投掷可能绕组定位元件，也会破坏的定位精度，甚至发生事故。因此，在这个过程中的铁屑不多，可适当增加定位装置和夹紧表面之间的距离增加的铁屑空间：对切削过程中产生更多的，一般应在夹具体上面。（5）安装应牢固、可靠夹具安装在所有通过夹安装表面和相应的表面接触或实现的。当夹安装在重力的中心，夹具应尽可能低，支撑面积应足够大，以安装精度要高，以确保稳定和可靠的安装。夹具底部通常是中空的，识别特定的文件夹结构，然后绘制夹具布局。图中所示的夹具装配。加工过程中，夹具必承受大的夹紧力切削力，产生冲击和振动，夹具的形状，取决于夹具布局和夹具和连接，在因此夹具必须有足够的强度和刚度。在加工过程中的切屑形成的有一部分会落在夹具，积累太多会影响工件的定位与夹紧可靠，所以夹具设计，必须考虑结构应便于铁屑。此外，夹点技术，经济的具体结构和操作、安装方便等特点，在设计中还应考虑。在加工过程中的切屑形成的有一部分会落在夹具，切割积累太多会影响工件的定位与夹紧可靠，所以夹具设计，必须考虑结构应便排出铁屑。4.6夹具设计及操作的简要说明为提高生产率，经过方案的认真分析和比较，选用了气动夹紧方式。这类夹紧机构结构简单、夹紧可靠、通用性大，在机床夹具中很广泛的应用。此外，当夹具有制造误差，工作过程出现磨损，以及零件尺寸变化时，影响定位、夹紧的可靠。为防止此现象，选用可换定位销。以便随时根据情况进行调整换取。总 结在设计过程中，我们读到一些技术资料和设计手册，在机械领域中的一些基本问题的探讨。因此，这样的设计不仅要加强自己的理解和知识，和他们的知识，拓宽。此外，该拉延工艺的设计，AutoCAD绘图软件的使用，并在同一时间，手绘，所有这些因素都使我们学到更多的知识，图像识别和提高我们的绘图能力。本课题是变速箱盖的加工工艺及夹具设计，主要是确定的工艺设计的工艺路线，确定加工和切削参数，基本工时，本设计的零件工艺路线是正确合理的，定位和夹紧的夹紧机构可实现定位和夹紧的目的，可以保证工件的加工精度。在很多问题的设计过程中，假设出现不合理工艺路线，甚无法保证夹具设计的准确性。在夹具设计中，由于定位基准的选择不合理，出现了定位或不定位零件加工精度无法保证。在夹紧机构由于尺寸的选择，如不合理，但没有达到夹紧的目的，也可能是由于位置的夹紧力和工件表面的作用所产生的营业额不合理。然而，在老师的细心指导的悉心指导下，经过三个月的努力，这些问题都一一解决方案。在这一过程中，加工工艺及夹具设计知识和更深入的了解，提高了综合专业知识的能力，我的专业知识，进一步提高技能，为以后从事专业技术工作。然而，在老师的细心指导的悉心指导下，经过努力，这些问题都一一解决方案。参 考 文 献1 李 洪工艺手册M 北京出版社，200612 陈宏钧实用金属切削手册M 机械工业出版社，200513 上海市金属切削技术协会金属切削手册M上海科学技术出版社，20024 杨叔子机械加工工艺师手册M机械工业出版社，20005 徐鸿本机床夹具设计手册M 辽宁科学技术出版社，2003106 都克勤机床夹具结构图册M 贵州人民出版社，200347 胡建新机床夹具M 中国劳动社会保障出版社，200158 冯 道机械零件切削加工工艺与技术标准实用手册M 安徽文化音像出版社，20039 王先逵机械制造工艺学M机械工业出版社，200010 马贤智机械加工余量与公差手册M中国标准出版社，19941211 刘文剑夹具工程师手册M黑龙江科学技术出版社，200712 王光斗机床夹具设计手册M上海科学技术出版社，20028致谢本课题是在XX老师指导下完成，非常感谢XX老师的耐心指导帮助。毕业设计是大学知识，相关的专业知识的综合运用，是知识在实践中的应用。通过本次毕业设计，使我的专业知识得到巩固和提高在原来的基础上，就离不开老师和同学的帮助。设计的分析是在老师的指导下完成的，在分析过程中，老师给了我很大的鼓励，在设计和分析使我觉得更多的设计思路，提高的学习能力，和讨论的问题的分析，有一个更清楚的了解，使我受益不浅。说实话，毕业设计真是有点累了。然而，明确其自身的设计结果，毕业设计仔细回味的旅程，一个罕见的成功立刻让我昏昏欲睡。虽然这是我刚学的第一个走，一点在我的生命中的成功，但它让我觉得更成熟了。通过这次的毕业设计，我深深地感受到，做任何事都必须有耐心，细心。有时是不小心计算误差，只能被无情地重做。但一想到老师教得比平时多，病人，认为他们的社会责任感的未来，思想在世界上是因为一些小错误，让人触目惊心的事故，我不能不提醒自己，要形成一个高度负责的好习惯，一丝不苟。发现自己的知识真的很差，他们的能力，用学到的知识是不够的，几年来学习很多毕业，今天才知道自己和不使用。想到这里，我真的有点不耐烦。学院机械加工工序卡片产品型号变速箱盖零件图号产品名称变速箱盖零件名称变速箱盖共5页第1页铣间工序号工序名称材 料 牌 号机加工40铣HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸件11设备名称设备型号设备编号同时加工件数铣床X52K11夹具编号夹具名称切削液1专用夹具普通乳化液工位器具编号工位器具名称工序工时 (分)准终单件22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/smm/rmm机动辅助1粗铣底部大端面铣刀,铣夹具,游标卡尺350130.5511510 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 期学院机械加工工序卡片产品型号变速箱盖零件图号产品名称变速箱盖零件名称变速箱盖共5页第2页铣间工序号工序名称材 料 牌 号机加工50铣HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸件11设备名称设备型号设备编号同时加工件数铣床X52K11夹具编号夹具名称切削液1专用夹具普通乳化液工位器具编号工位器具名称工序工时 (分)准终单件22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/smm/rmm机动辅助1精铣底部大端面铣刀,铣夹具,游标卡尺5001.270.8311510 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 期学院机械加工工序卡片产品型号变速箱盖零件图号产品名称变速箱盖零件名称变速箱盖共5页第3页铣间工序号工序名称材 料 牌 号机加工60铣HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸件11设备名称设备型号设备编号同时加工件数铣床X52K11夹具编号夹具名称切削液1专用夹具普通乳化液工位器具编号工位器具名称工序工时 (分)准终单件工步号工 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/smm/rmm机动辅助1粗铣顶部平面铣刀,铣夹具,游标卡尺350130.5511510 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 期学院机械加工工序卡片产品型号变速箱盖零件图号产品名称变速箱盖零件名称变速箱盖共5页第4页铣间工序号工序名称材 料 牌 号机加工70铣HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸件11设备名称设备型号设备编号同时加工件数铣床X52K11夹具编号夹具名称切削液1专用夹具普通乳化液工位器具编号工位器具名称工序工时 (分)准终单件22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/smm/rmm机动辅助1精铣顶部平面铣刀,铣夹具,游标卡尺5001.270.8311510 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 期学院机械加工工序卡片产品型号变速箱盖零件图号产品名称变速箱盖零件名称变速箱盖共5页第5页铣间工序号工序名称材 料 牌 号机加工80钻HT200毛 坯 种 类毛坯外形尺寸每毛坯可制件数每 台 件 数铸件11设备名称设备型号设备编号同时加工件数钻床Z52511夹具编号夹具名称切削液1专用夹具普通乳化液工位器具编号工位器具名称工序工时 (分)准终单件22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/smm/rmm机动辅助1钻8-12孔钻头,专用夹具,游标卡尺50012.70.5211510 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G. Seliger et al. (eds.), Advances in Sustainable Manufacturing: Proceedings of the 8th Global Conference 149 on Sustainable Manufacturing, DOI 10.1007/978-3-642-20183-7_22, Springer-Verlag Berlin Heidelberg 2011 Methodology for High Accuracy Installation of Sustainable Jigs and Fixtures J. Jamshidi, P.G. Maropoulos Department of Mechanical Engineering, University of Bath, UK Abstract The ability to accurately measure the components of jigs and fixtures during their installation determines the state of their precision, especially for large size products and applications. This matter is crucial in mass customisation where small batches of products and components with high variety in design are manufactured. Product quality should be in harmony with rapid changeover philosophy as compromising quality for speed is not forgivable for sensitive components and assemblies such as those seen in the aerospace industry. It is necessary for the installation of the jigs and fixtures to be highly accurate in order to minimise the use of tolerance budget due to variations in jigs and fixture positioning. Major overhead costs for jigs and fixtures particularly in the aerospace industry led to the development of the concept of flexible and reconfigurable jigs and fixtures. Reusability of reconfigurable jigs and fixtures makes them attractive for sustainable solutions as their components can be reused for several variant of a product or assembly. The main drawbacks of this type of jigs and fixtures have been their poor accuracy and reliability. In this paper accurate positioning of the key components of sustainable jigs and fixtures is investigated. The factors affecting the performance of the jigs and fixtures are reviewed from the installation stage. The paper introduces a methodology for minimising uncertainties in positioning of the holds and clamps for flexible jigs and fixtures. Keywords: Sustainable Jig, Jig installation, Calibration Uncertainty, Jig Monitoring, Metrology, Reusable Jig 1 INTRODUCTION Factors such as quality and reliability have long converted to implicit characteristics of the new products. Recent market trends have forced manufacturing industries to move towards mass customisation in their products and service range. Increased variation in the design of new products is followed by a second wave of variation with higher amplitude at subassemblies and component level. State of the art manufacturing systems and technologies have provided more flexibility, enabling designers to think more freely. For instance new large volume measurement systems, developed in the past few years, are capable of measuring several decametre distances. Such technologies facilitate the verification of large size components that used to be manufactured from several assembled components. The manufacturing of large size products requires specialist jigs and fixtures in order for their components to be held in the desired orientation during build and assembly. This requires major overhead cost that can only be justified by mass production in some cases or otherwise the cost of finished products can be very high. This issue contradicts with the market trends where customers are constantly looking for higher value for their money. In a typical product the variation in the product creates a more sustainable business as it can fulfil the needs of a relatively larger market. Flexible and reconfigurable jigs and fixture that can be formed in different shapes to support different variation of products is a key solution for the above challenges. The concept of flexible jig existed for several years in the research domain 1. However, they are not fully utilised to a great extent in real production facilities especially for large size product manufacturers, such as aerospace. This is due to the challenges related to their initial installation, poor calibration, and repeatability that often exceed the tolerance requirement. The manufacturing of these jigs and fixtures from high quality key components as well as their integration with large volume metrology systems can reduce the above limitations. This paper covers metrology issues related to the installation and calibration of flexible jigs and fixtures as well as their monitoring during service. 2 RELATED WORK 2.1 Manufacturing and assembly of large scale parts Typically prior to precision manufacturing of mechanical parts it is essential to move the raw material to the machine bench, proceed with rough cutting then fine alignment and clamping. At this stage the part is ready for machining of its high precision key features. However, this is not always possible for large size and/or heavy components. Large scale products refer to those with components that are not economically possible to handle or move around in the factory for fabrication and assembly purposes 2. The manufacturing and assembly processes of these parts encompass movement of the machines and systems to the desired location and orientation with respect to these parts. Such parts are normally held in their positions using large size jigs and fixtures. If these parts are produced in small batch sizes that is the case for aerospace industries, high overhead cost per product will occur. There have been many attempts to design and manufacture jigs and fixtures so that they can hold a number of variants of components 3, 4. However, this approach is not feasible for parts with sensitive or key features due to their high accuracy requirements. J. Jamshidi, P.G. Maropoulos 150 Adjustable, reconfigurable jigs and fixtures produce lower repeatability over time compared to fixed ones. Fixed jigs have permanent topology achieved through their permanent joints that are welded or riveted. Mechanical failure of these jigs and fixtures for example due to fatigue and plastic deformation is a main cause of terminating their service and sending them for recycling. With small batch manufacturing requirements it is now common to retire a conforming jig as their service life depends on the life of products. In other words soon after the cease of manufacturing a parts variant, the associated jigs and fixtures become redundant. Even if the jigs are still in working order, they have to be scrapped and sent for recycling. This method brings the burden of high energy consumption for recycling. Even for the fixed jigs and fixtures the drift in the large size parts and jig can affect the accuracy of a large size assembly 5. Several methods for analysing jig rigidity have been developed 6 to evaluate the impact of vibration on large size jigs. In any case a more sustainable manufacturing can only be achieved by alternative solutions. Figure 1: Typical components of large scale jig (image courtesy of Electroimpact /G150TFIX/gallery.asp) Extensive lead time to manufacture is another major drawback for fixed jigs and fixtures. These jigs should be ordered well in advance of any manufacturing processes. This can create additional complexity in production planning and product time to market. Regardless of their type, large scale jigs have a number of common elements including one main frame, one or a number of inner frames, potentially one or a number of moving mechanisms, and smaller components such as clamps, bushings, pickups and adjustable screws (Figure 1). 2.2 Flexible jigs and fixtures The concept of flexible jigs and fixtures is developed for increased sustainability, rapid changeover as well as low cost. It is now possible to use off the shelf modules and clamps for jigs and fixtures design and assembly. Depending on the requirement only a handful of specialised components for the jigs and fixtures might be needed to be custom designed and manufactured. In this concept the majority of bulk components, joints at the attachments are used in for a specific application. Once the product design variant is fully manufactured it is then possible to disassemble the above components and reassemble them in a new topology to suite the next design variant. This cycle can be repeated over a large number of times resulting in reduced overhead cost for jigs and fixtures. Needless to mention the other factors such as disassembly time, resetting time, operators time should be considered for evaluating the real cost benefit of using this type of jigs and fixtures. This approach best reduces the cost of jigs and fixtures for the assembly and component ranges that are fairly close in design. Depending on the level of variations in the components and the type of work required on each a different percentage of the flexible jigs need to be rearranged. This matter is crucial to be considered at design stage in order to increase the benefit of using this type of jigs and fixtures. For example, when possible, the location and 3D positioning of pickups and clamps on different variants of the component or even totally different parts should be in close proximity to increase compatibility and inter-changeability of sub-systems of jigs and fixtures. Having a collection of the key components of the jigs can guarantee the availability of the desired jigs in a short time. In addition to this the storage of the jigs required less space as it is possible to dismantle all the modules that are typically in the form of scaffolding and place them next to each other. Flexible jigs are currently utilised in some of the automotive companies (Figure 2) as their accuracy level is sufficient for this sector. Despite the above benefits there are Clamp Main frame Inner frame Component Adjustable holds Moving mechanisms Methodology for High Accuracy Installation of Sustainable Jigs and Fixtures 151not many flexible jigs in operation in large size manufacturing facilities such as aerospace factories. Accuracy and uncertainty of positioning pins, repeatability of the clamps and drift of the jig structure are all contributing to the fact that these jigs cannot meet the tolerance requirements of the power generation and aerospace industries. These jigs have high potentials for utilisation in the above industries once their accuracy problems are resolved. Figure 2: Fixture with reconfigurable components for automotive industry (image courtesy of Witte http:/www.horst-witte.de/en/) There has been a number of new developments in large volume metrology systems and technologies. Modern laser based metrology systems and technologies are now capable of measuring large size products up to several decametres with acceptable accuracy. These systems can be used to accurately position mountings of the key components of the jig during its installation and initial setup. The installation of jigs and fixtures typically starts form its base or main frame then large components and gradually to the smaller components such as pickups and clamps. Metrology systems can be used for the installation of flexible jig main frame and its inner frames to guarantee the correct positioning of each and every component. Table 1 shows a few of these large scale measurement systems. For technological review of these systems see 7. Laser tracker systems capable of measuring reference points, are among the most suitable measurement systems for this purpose. The instrument tracks a Spherically Mounted Retroreflector (SMR) target the position of which can be registered in three dimensional space. SMR can be contacted directly with the target object to provide geometrical positional information or can be used within a mechanically repeatable SMR nest known as Laser tracker target or in short target from this point on. Laser trackers like any other measurement instrument have a level of uncertainty that need to be accounted for during the jig installation process. Also the line of sight issues between the laser tracker and its target point should be considered and if necessary multiple tracker positions should be used. In real measurement activity the result must be accompanied with a statement of uncertainty. Such statement characterises the dispersion of the values that are reasonably attributed to the measurand 8. This issue is the same for the installation and later verification of any jig or fixture. This knowledge clarifies the jig capability of a given positioning and assembly task. In other word it indicates if a jig can meet the tolerance requirements for its related processes. 2.3 Comparison of jig philosophies There are a large number of different shape and design jigs and fixtures in different companies for various manufacturing and assembly applications. Some of these jigs and fixtures are readily available in standard forms, while some are designed and manufactured specific to particular parts and tasks. The latter can be very expensive based on the complexity and scale of the products 9. Regardless of cost and purpose a manufacturing or assembly process can be performed using with no jig, with fixed frame jigs, or with reconfigurable or flexible jigs. Table 2 provides a comparison of these methods with their typical applications. Fixed frame jigs are typically for heavy duty applications. They are more suitable for applications with a large number of products that can relax the overhead cost of the jig. There are several advantages in the application of flexible jigs and fixtures for the manufacturing and assembly of large and complex products. In particular for research and development work, as well as for cases where low volume products are manufactured flexible jig and fixture can be very beneficial. In addition to time and money saving benefits the possibility of having a flexible jig gives more freedom to the design, manufacturing and assembly processes due to the low direct and recurrent cost of changing the overall topology of the jig. Reconfigurability and reusability of flexible jig is a main Clamp Main frame Inner frame Component J. Jamshidi, P.G. Maropoulos 152 advantage for this type of jig compared to conventional jigs. This is particularly important as it is in line with the industry direction in terms of green manufacturing by recycling components from a used system, reducing project costs with regards to expenses for tooling of associated items. Table 1: Examples of large volume/portable measurement instruments for jig verification Measurement type Instrument Auxiliary components Contact Non-contact Image SMR probe ? Laser Tracker T-probe ? Laser Radar Spherical targets ? Targets ? Photogrammetry Light projection ? Laser based scanning head ? Articulated Arm CMM Contact probe ? 3 FLEXIBLE JIG INSTALLATION The issues and concerns that need to be considered in the jig installation procedure are described in this section. The installation of the jig components in the right position can be a challenging especially when the positioning tolerances are tights. Flexible jigs should also be monitored in order to exploit and compare their rigidity with that of the conventional ones. Stage by stage measurement instruction for the jig installation based on the results of an initial jig setup in the simulation software environment and practical experiment of a large size jig with dimensions of 5m x 4m x3m is given in a generic description. This is regardless of whether the jig is in first time installation or it is a change of an existing jig topology into a new shape, for holding a different component. Depending on the complexity a typical large size jig has between three to five levels of frames. Apart from the base level with normally one main frame, at each level there can be one or several frames. These frames are interrelated with reference to the jig datum in order to facilitate the positioning and functionality required. In an automated, fixed platform, robotic systems carry out several tasks such as part positioning, machining and assembly. The robot working datum therefore is linked with the working frame of the jig. Careful consideration of jig datuming strategy and its subsequent installation can secure achieving the desired tolerance. 3.1 Measurement assisted flexible jig installation There are several stages for the installation of flexible jigs that can be carried out in first simulation and then real world. The use of simulation exercise can reduce the number of potential errors and rework during this process. The process of measurement assisted installation is similar to tracking objects to position that is common for large size assemblies. In this approach the components of the jig are roughly positioned, within 1mm tolerance from the target position, at first. Then when all of the jig components are attached into their designated positions, within 0.1mm to 0.15mm tolerance, they are tightened using the appropriate torque. The typical stages of metrology assisted flexible jig installation are given below: 1. setting initial reference frames in the factory 2. measurement of initial reference frame 3. installation of base or main frame in its position 4. installation of inner frames offline 5. installation of holding and positioning brackets 6. installation of clamps, bushings and pickups in their rough position on inner frames and main frame 7. installation of inner frame on the base frame 8. fine adjustment and fastening of key locating components 9. verification of reference frames and clamps 10. in service monitoring of key positions on the jig These stages are related to the complete installation of the jig from the scratch. Needless to mention that in case of slight Methodology for High Accuracy Installation of Sustainable Jigs and Fixtures 153change in design variation some of the following operations will be omitted. Table 2: A brief comparison between different jig philosophies Typical characteristic Fixed frame Flexible jig Jig-less Application Large volume production Low volume production Prototyping Uniqueness Repeatable Reconfigurable Cost effectiveness Durability Very high High Low Pros Rigidity Very high Uncertainty rigidity Low Weight Heavy Medium Low Portability Non-portable Difficult component positioning in each setup Difficult to program Cost Very high Medium Low Cons Manufacturing time Long Medium Short 3.2 Algorithm for flexible jig installation The installation processes for flexible jigs take the following main stages: 1. the installation of main frame of the jig 2. the assembly of moving units and sub-systems 3. the installation of the jig inner frames on the jig assembly 4. the assembly of pickups and clamps on the jig. The main frame is the backbone of the jig that is typically fixed for a large number of jig topology and design variations. Therefore it does not change in shape as regularly as the inner frame or the smaller elements of the jig such as bushings, pickups and clamps. Careful consideration of the manufacturing process can reduce the necessity of rearranging larger elements of the jig components resulting in further time and money saving. Figure 3 in three separate groups of activities shows the processes of flexible jig installation. In this process it is assumed that the standard parts of the jig are selected from the available, off the shelf sections and components. Then in advance of the physical installation a number of tests and trials are carried out to plan the jig installation in such a way that the uncertainty of measurement is reduced. Once the acceptable level of uncertainty is achieved the physical installation can take place. Figure 3: Measurement assisted installation procedure for flexible jig J. Jamshidi, P.G. Maropoulos 154 In jig installation process it might be required to use multiple measurement system or a measurement system from several locations to cover the complete set of key points for jig installation. This should include the auxiliary target reference points that are placed on the factory floor and wall for stability and drift check during the jig service. During the localisation of the key points on the jig the uncertainty of the measurement instrument should be taken into account. As a rule of thumb the accuracy of the jig positioning for each key location should be in an order 10 times better than the required tolerance. In other word if the tolerance on the component is specified as 0.1mm the accuracy of the jig positioning should be at least 0.01mm. The best practice approaches for the flexible jig installation are given below: 1. A planned position for the initial reference points on the factory wall and floor is preferred in order to minimise uncertainty of the measurement. 2. The instrument position should be verified on regular bases using the initial reference points. 3. On each large section of the jig several SMR nests can be attached for better tracking and repeatability. 4. Where the large components of the jig have bend or twist the level measurement should be focussed on the central section of the beams to reduce angular positioning error. 5. The reference points on the inner frames should be selected as distant as possible for creating frame coordinate systems. This can result in smaller uncertainty when in the inner frame coordinate system. 4 UNCERTAINTY Uncertainty if defined by GUM 8 as the result of the evaluation aimed at characterising the range within which the true value of a measured object is estimated to lie, generally with a given confidence. The Uncertainty here is reviewed from two aspects, the first is related to the measurement process and the second is related to the uncertainty of jig positioning. Measurement uncertainty has a number of contributing factors such as variation in environmental conditions such as dust, gravity temperature, air pressure and humidity, systematic errors within the measurement instrument and its related software, operators skill, wear of contact probes or SMR. Based on GUM 8 definition a measurement result should be accompanied by its statement of uncertainty. Detailed discussion of these sources of errors is out of the scope of this paper. There have been a number of studies to establish the true uncertainty of some of the measurement instruments 10, 11. The measurement results of key points on jigs and fixtures should therefore include the related confidence level. In addition to the initial uncertainty rising from the measurement instrument, the jigs and fixtures have other contributing sources of uncertainty. Forces applied to the jig frame due to weight of the product and also by manufacturing processes can potentially create elastic deformation in the jig frame. This matter becomes more complex for jigs that have integrated and automated moving sections. Careful consideration of the sources of uncertainty at the jig design stage can reduce the risk of overusing the tolerance budget in a given scenario. There is a direct relation between the level of accuracy and cost of jigs and fixtures. However, the overall cost of manufacturing should be considered. The parts that have high number of first pass have longer life. In other words the parts that have quality characteristics closer to their mean values seldom fail during their use. The move towards six sigma approach is imperative in the installation and then monitoring of reconfigurable and flexible jigs and fixtures for high precision and sensitive parts. 5 DISCUSSION Flexible jigs are suitable for assembly and minor machining of a number of parts with different design and geometry. In particular when the design variations between these parts are small this type of jigs proves to be a cost-effective and fast solution. This is because it is possible to adopt the jig to a new product or component variant with minor reconfiguration of the jig. However, when the design of the desired part and assembly is totally different or with different dimensions a complete rearrangement of the jig components may be required. Therefore in designing a new topology for the jig the closeness of the design variant of the parts and sub-assemblies should be considered in order to minimise the time and cost of jig installation and reconfiguration by maximising the reuse of the existing components in the current configuration. There are a number of ways in which a flexible jig can be assembled simply due to its flexibility. The selection of the right components in the right installation order can maximise time and cost savings. In this selection procedure the potential reuse of the jig for future products should be taken into account. In the case of constant product variation it is important to plan and design jig topology in a collective approach where the mine frame of the jig that is more time consuming and costly can be reused without disassembling for instance. The use of bespoke clamps, fasteners, bushings and other elements of the jig are key issues to the cost reduction. Extensive use of simulation software and tools can reduce costs associated to rework and waste of jig material. The use of these software help plan for instance the line of sight check between the measurement instrument and its target point. Figure 4 shows the first stage of flexible jig installation in the measurement simulation software. As the jig is being built the benefit of simulation becomes more evident as it can highlight the line of sight issues and uncertainty level of an instrument with respect to the target measurement points. Figure 4: Simulation for measurement assisted jig installation Potential drift and deformation of jig component due to weight and forces related to the jig operation can be analysed in the simulation world well in advance of any financial commitment Jig main frame Measurement system Target points Line of sight Methodology for High Accuracy Installation of Sustainable Jigs and Fixtures 155with regards to purchasing jig components. Furthermore such tools allow better planning for assembly and manufacturing operations as they can reveal the strengths and weaknesses of the jig prior to its physical setup. The selection of the right measurement instrument is paramount for successful metrology assisted jig installation. A coherent metrology system with known uncertainty values in its measured results can determine jig accuracy and also expose the capability of the jig and its conformity for the required task within a given tolerance. 6 SUMMARY Parts and assemblies should be designed in such a way to minimise the cost of jigs and fixtures by accommodating the use of standard components. If thought in advance the speed and cost of changeover of jigs and fixtures for the next variant of products can be increased. The design of jigs and fixtures in their turn can have strong implementation on the total cost, carbon footprint and their sustainability. It is often required to manufacture only a handful of a typical design or a product, subsystem or a component to satisfy variability of products a