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冲床自动送料机构设计（180mm）摘要：在现代工业生产自动化领域里，材料的搬运、机床送料、整体装配等实现自动化是非常必要的。然而送料是一想重复且十分繁重的工作，为了消除累积误差、提高生产效率，减轻体力劳动，保证生产安全，所以采用自动送料机构是行之有效的方法。本文首先介绍了机构的选择，接着讲述了自动送料机构原理与分析过程，零部件的设计与选择过程等。最后通过校核、修改等步骤后，表明本设计中的双棍轴齿轮送料机构设计适合设备的生产与需要，并能够实现间歇送料与机械化与自动化，从而大大地提高了生产效率。关键词：冲压；间歇送料；自动化IDesign of automatic feeding mechanism for punch(180mm)Abstract:In the field of modern industrial production automation, the to automation of material handling, machine feeding and assembly is necessary , and feeding is think of a repetitive and very hard . In order to eliminate the cumulative error , improve the production efficiency, reduce the physical labor and ensure the safety of production, the method of automatic feeding mechanism is adopteed.The principle and analysis process of automatic feeding mechanism, the design and selection process of parts are introduced in this paper. Finally through check, modify, and other steps, which indicates that the design of the roller type gear conveying mechanism design is suitable for the production and equipment needs, and can realize the mechanization and automation, thus greatly improve the production efficiency.Keywords: Punching ,intermittent feed, automation目录III摘要IABSTRACTII1 绪论11.1 冲压在机械制造中的地位及特点11.2 国内外研究现状22 冲床自动送料机构总体方案设计43 自动送料机构的设计63.1 送料机构的概述63.1.1 送料机构的原理63.1.2 辊轴送料机构的送料时间及其调整方法63.1.3 本节小结73.2 辊子的设计73.2.1 辊子的尺寸设计73.2.2 压紧装置83.2.3 抬辊装置93.2.4 离合器的设计93.2.5 驱动机构103.2.6 本节小结113.3 其它零件113.4 轴的设计及校核113.4.1 下辊轴的设计123.4.2 大齿轮轴的设计与校核153.4.3 本节小结183.5 轴承的计算和校核183.6 齿轮的设计及校核203.6.1 初步设计203.6.2 齿轮的校核计算203.6.3 本节小结243.7 键的设计和校核243.7.1 平键 1 的设计和校核243.7.2 平键 2 的设计和校核253.7.3 平键 3 的设计和校核253.7.4 本节小结264 润滑与密封274.1 润滑274.2 密封27参考文献28致谢30附录 A 英文文献311绪论冲床或称冲压机,是一种普遍使用的金属机械冷加工设备，冲压工艺由于比传统机械加工来说有节约材料和能源，效率高，对操作者技术要求不高及通过各种模具应用可以做出机械加工所无法达到的产品这些优点，因而它的用途越来越广泛。随着机械行业向着先进制造技术方向的发展，计算机技术在机械设计与制造中的得到了广泛的运用，对于我而言，将学习到机械产品设计与制造方面的基础知识与计算机辅助设计与制造技术相结合，联系实际的机械产品结构设计，既可以强化机械设计意识，培养我的机械运动方案与结构创新能力。在现代工业生产自动化领域里，材料的搬运、机床送料、整体装配等实现自动化是非常必要的。然而送料是一想重复且十分繁重的工作，为了消除累积误差、提高生产效率，减轻体力劳动，保证生产安全，所以采用自动送料机构是行之有效的方法。冲压是金属塑性变形成形加工的基本方法之一，它主要用于加工板料零件，冲压既能够制造尺寸很小的仪表零件，又能够制造大型零件；既能够制造一般尺寸公差等级和形状的零件，又能够制造精密和复杂形状的零件。冲压具有生产效率高、加工成本低、材料利用率高操作简单、便于实现机械化与自动化等一系列优点，因此在汽车，机械、家用电器、点击、仪表、航空航天、兵器等生产和发展具有十分重要的意义。而自动送料冲床又具有高效率等特点，所以说自动送料冲床在今后的生产中具有很大的发展空间。1.1 冲压在机械制造中的地位及特点冲压既能够制造尺寸很小的仪表零件，又能够制造诸如汽车大梁、压力容器封头一类的大型零件；既能够制造一般尺寸公差等级和形状的零件，又能够制造精密（公差在微米级）和复杂形状的零件。占全世界钢产 60%70%以上的板材、管材及其他型材，其中大部分经过冲压制成成品。冲压在汽车、机械、家用电器、电机、仪表、航空航天、兵器等制造中，具有十分重要的地位。冲压件重量轻、厚度薄、刚度好。它的尺寸公差是由模具保证的，所以质量稳定，一般不需再经机械切削即可使用。冷冲压件的金属组织与力学性能优于原始坯料，表面光滑美观。冷冲压件的公差等级和表面状态优于热冲压件。大批量的中、小型零件冲压生产一般是采用复合模或多工位的连续模。以现代高速多工位压力机为中心，配置带料开卷、矫正、成品收集、输送以及模具库和快速换模装置，并利用计算机程序控制，可组成生产率极高的全自动冲压生产线。采用新7型模具材料和各种表面处理技术，改进模具结构，可得到高精度、高寿命的冲压模具，从而提高冲压件的质量和降低冲压件的制造成本。冲压生产的工艺和设备正在不断发展，除传统的使用压力机和钢制模具制造冲压件外，液压成形以及旋压成形、超塑成形、爆炸成形、电水成形、电磁成形等各种特种冲压成形工艺亦迅速发展，把冲压的技术水平提高到了一个新的高度。特种冲压成形工艺尤其适合多品种的批量（甚至是数十件）零件的生产。对于普通冲压工艺，可采用简易模具、低熔点合金模具、成组模具和冲压柔性制造系统等，组织多品种的中小批量零件的冲压加工。总之，冲压模具有生产率高、加工成本低、材料利用率高、操作简单、便于实现机械化与自动化等一系列优点。采用冲压与焊接、胶接等复合工艺，使零件结构更趋合理，加工更为方便，可以用较简单的工艺制造出更复杂的结构件。1.2 国内外研究现状随着市场经济的发展，国内、国际市场竞争日益激烈，产品更新更为迅速， 尤其是随着机械行业的发展，冲压制件类型、工艺、外形越来越复杂，精度要求越来越高，传统的冲床已经不能满足要求，以及制造冲压件用的传统金属材料， 正逐步被高强钢板、涂覆镀层钢板、塑料夹层钢板和其他复合材料或高分子材料替代。随着材料科学的发展，加强研究各种新材料的冲压成形性能，不断发展和改善冲压成形技术。在模具设计与制造中，开发并运用 CAD/CAM 系统，发展高新制造技术和模具、装置等，以适应冲床产品的更新换代和各种生产批量的要求。推广应用数控冲压等设备，进行机械化与自动化的流水线冲压生产。要想提高生产效率，就必须提高生产的自动化程度，自动送料机构就是为了实现生产中送料工序自动化而设计的一种专用机构。自动送料机构可将冲压料或冲压件经过定向机构，实现定向排列，然后顺序地送到机床或工作地点。这在自动化成批大量生产中显然是实用的，不但可以把操作人员从重复而繁重的劳动中解脱出来， 而且对保证安全生产也是一种行之有效的方法。这使我国的机械制造业得到了质的提升。目前，我国汽车制造业飞速发展，而对这一形势，我国的板材加工工艺及相应的冲压设备都有了长足的进步，有重型机械压力机机器覆盖件生产线、大型多工位压力机、数控板冲、剪拆机床及柔性加工生产线、无模多点成形压力机、高速压力机等国外冲压机床开始采用伺服电机进行控制。中国冲压机床行业进过技术引进、合作生产及合资等多种方式的运作，快速地提升了我国冲压机床设备整体水平。近年设计制造的许多产品，其技术性能指标已经接近或达到世界先进水平，但由于大家都在进步，所以国内成品与国外名牌产品的差距并无明显缩短。因此，我国冲压设备行业和企业须以战略的思路和有效的措施应对当前的机遇和挑战。自动送料机构就是为实现生产中送料工序自动化而设计的一种专用机构。自动送料机 可将冲压料或冲压件经过定向机构，实现定向排列，然后顺序地送到机床或工作地点。这在自动化成批大量的生产中显然是实用的，不但可把操作人员从重复而繁重的劳动中解脱出来，而且对保证安全生产也是一种行之有效的方法。目前，国内拥有大量的冲压机床，如果能把它们改造成半自动或自动机床， 将会充分发挥机床的潜在力量，这是一个具有重大意义的事情，而在机床上安装自动送料机构，这将大大提高冲压的生产效率，实现冲压的完全自动化。2冲床自动送料机构总体方案设计为了完成对冲压机床的自动送料过程，本次采用机械送料机构，目前国内外有多种方式能达到自动送料，下面主要讲述了如何运用机械装置完成自动送料。冲床自动送料机构主要分为了送料装置、压紧装置与传动件装置两类。本设计属于机械送料装置。由于本次所给的材料比较薄，只要能平稳顺利的完成送料， 到达预期的送料精度，根据其结构的难易程度与成本的高低，双棍轴送料机构成为了我们首选的机构。图 2.1 单边辊轴送料装置结构简图Sn - 为板料送进距离n - 为压机频次B - 为板料厚度H为冲压滑块行程- 为许用压力角Fb为板料送进阻力Fr为冲压板料时的阻力为速度不均匀系数e=0取 R1=Rb底面至冲床工作台面距离为 2050mm板料送进运动原理：大齿轮带动小齿轮运动，同时上辊轴被压紧，所以被上下辊轴压住的板料就被带动向前行进。曲柄滑块运动原理：曲柄可运动循环 360 度，同时带动着滑块上下运动。当滑块运动到最低点时，切掉板料，同时板料送进运动停止。当滑块完成切料，又向上运动时，板料运动也开始运动。板料送进运动和曲柄滑块上下运动是同时做循坏运动，就顺利完成了自动送料。表 1.1 单边辊轴自动送料装置题目的原始数据方案Sn/mmn/次/分B/mmH/mmFb/NFr/Na/度Rb/mmR2/mmR/mmL/mmx/mmy/mm11801203805902900250.046012018013003701250送料间距的大小按下式计算：s = pd1 a= 240 90 = 180mm360360当送料间距 S 确定时，一般可以调节主动辊直径 d1 和转角，使送料间距达到要求。辊轴的直径和送料时圆周速度和 S 转角密不可分，主动辊的直径计算方式为D = 360S1pa从动辊的作用相对小一些，自然结构上的设计也比较简单，为保证两滚轴能同时运转，所以要求他们的齿数与直径成比例。d1 = Z1 d2Z2在送料时需要先将材料放在送料装置上，所以要将上辊抬起，所以需要我们设计一个抬辊的装置，有两种作用。一种是在开始装料时需要将上棍子抬起，使两辊之间有一定的间隙，以便材料能顺利通过。另外一种抬辊的作用是在当每次把材料送进去之后，在冲压工作之前，让材料不受任何约束。第一次采用手动抬棍，需要在上辊装一个手柄，以便于手动抬棍 ；第二次抬辊动作需要我们设计杠杆式抬辊装置，利用螺杆来推动杠杆完成抬辊动作。3 自动送料机构的设计3.1 送料机构的概述3.1.1 送料机构的原理图 3.1 机构送料与运动循环图从图 3.1 可知，冲床自动送料是由板料送进与滑块上下行进同时进行的。板料送进运动原理：大齿轮带动小齿轮运动，同时上辊轴被压紧，所以被上下辊轴压住的板料就被带动向前行进。曲柄运动原理：曲柄连接着两个运动，一个是曲柄滑块运动，一个是曲柄摇杆运功。这两个运动是同时进行的，并且曲柄摇杆连接着板料送进运动。1. 曲柄滑块运动原理：曲柄是绕固定点旋转，并且带动着滑块上下运动。由于曲柄不停循环 360 度作运动，则滑块也上下做周期性的运动。2. 曲柄摇杆运动原理：曲柄运动带动着大齿轮运动，而大齿轮与小齿轮啮合， 也就是顺着带动小齿轮向前转动。由于小齿轮（下辊轴）与上辊轴合力压住了板料，板料同时也被带动着向前运动，着也就是板料送进运动。可知此时曲柄也不停循环 360 度作运动，则齿轮运动也是周期性的运动。板料送进运动和曲柄滑块上下运动是同时做循坏运动，就顺利完成了自动送料。3.1.2 辊轴送料机构的送料时间及其调整方法滑块的起点是滑块的最高点。当滑块下降到开始时，冲压的角度是冲压的开始角度，而在冲压结束时的角度是冲压结束角。然后滑块继续下降到最低点，然后完成滑块的上行动作。通过调整送料的转角找出曲柄转动时,板料不动与板料送进时他们之间产生的转角。为了确保材料被冲压，板料应处于不可移动的位置。为了保证板料进给速度较低，有必要尽可能多地制造金属板的进给时间。由上面可知送料送进和滑块上下是同时进行的。滑块在最低点时，停止送料， 其余滑块运动在除最低点时，曲柄转角大概在 270 度到 90 度之间，板料都在送料。设定好送料距离，可以通过改变偏心的圆周位置来达到精确送料。用这个方法实际就是通过改变送料的快慢，以与滑块的上下运动匹配，保证送料的顺利完成。3.1.3 本节小结主要叙述了送料机构的工作原理、工作过程，采用双辊轴送料机构以及送料时的简图说明，完成冲压时候的工序，当冲压过程进行完毕后，冲头回升到一定高度，冲头与工作面将材料脱离时才能继续送料，辊轴送料机构的送料时间应尽可能的使板料送进时间大于板料不动的时间。3.2 辊子的设计3.2.1 辊子的尺寸设计辊子是本次设计的送料机构的主要工作零件之一。在送料过程中，辊子会直接与材料表面产生摩擦从而到达送料，所以就要求辊子表面应具有较好的耐磨性和几何尺寸及精度要求。求辊轴转角a = Sn 180 = 180 180 = 173Rp Rbp 60摇杆摆角a = a R1 = 173 60= 86R2AR120本设计主动辊为下辊d1 =360 s a= 360 180 86= 240mm9S-送料进距（mm）a- -下辊转角（ ），即摇杆摆角，一般从动辊直径 d 2可设计的稍小些。a 100 。从推荐的中心距系列中暂选a = 230mm, d = (a - d1 ) 2 = (230 - 240 ) 2 = 220 mm2 i = d 2d12= n1 n2= Z 2Z1= 2202402= 0.917n1 - -下辊转速（r / min）； n2 - -上辊转速（r / min）； Z1 - -下辊传动齿轮齿数； Z2 - -上辊传动齿轮齿数。辊子长度一般取L = B + (10 20) = 130.4 + 20 = 150.4mm,圆整后取L = 150mm。3.2.2 压紧装置送料能否进行主要是大齿轮带动棍轴运转，而在棍子与材料之间没有进行固定，要使棍子能带动材料的运送，就必须让上下辊压紧材料，才能保证顺利运送材料，因此就要设计一个压紧的装置，使送料达到要求的精度。利用弹簧的压紧力来使上辊与平面达到要求的压紧程度，结构简图如下图：图3.2板簧式压紧装置原理图自动送料装置中上棍子的压紧装置是在上辊加一对弹簧使上辊与工作面压 紧，而且弹簧的压紧程度可以根据我们所需要来平衡，从而达到精确送料的目的。3.2.3 抬辊装置在送料过程中需要抬辊装置来放松辊子，毕竟板料不是一直都在冲床上，一直处于被送进的状态。与压紧装置一样，作用的对象都是上下辊，不过主要是针对上辊。抬辊装置是让上辊向上移动一点高度，使其与下辊不在将板料压紧，使胚料处于自由的状态，可以送进或者调整。本次设计机构送料过程中需要两次抬辊：一次是在胚料装进冲床时，需要上辊抬起，将其送入上下辊的间隙；第二次时将要切料时，而此时以将胚料送到了指定位置，这时需要抬辊，以调整胚料的位置，更好的切料。抬辊装置有撞杆式、气动式等。为了更便捷和更有效，本次设计在第一次抬辊动作中没有选择以上几种，而是选择手动。所以在抬辊中装上一个手柄，使它与撞杆式抬辊装置连在一起，利用杠杆原理实现，就巧妙和简便的达到了抬辊要求。图3.3 抬辊装置原理图3.2.4 离合器的设计根据实际情况，本次设计使用的是滚柱式内星轮无拨爪单向超越离合器。滚柱式内星轮无拨爪单向超越离合器常用于驱动辊轴送料机构的辊轴，根据间歇机构那可知超越离合器使送料机构的辊轴产生间歇转动，以达到按一定规律自动送料的目的。一般，它允许的压力机滑块行程数小于 250 次/min，送料速度小于 45m/min。本设计选用的压力机滑块行程数为 170 次/min,送料速度 v=120 0.240=28.8m/min，满足要求。由文献6,选用 D=100mm 的超越离合器，滚柱数 Z=3，许用转矩 T=70N.m允许总结合次数为5106，允许最高接合次数为80 次/min，极限转速为1000r/min，接合式的最大空转角度为 1。图 3.4 离合器结构图3.2.5 驱动机构冲床自动送料机构是利用曲轴作为其驱动源件，它的动力源机构是用曲柄摇杆带动其运转的。这个机构主要的零部件有曲柄滑块、连杆、曲柄摇杆。根据压力机尺寸，暂取曲柄摇杆机构尺寸如下：19机架中心距曲柄半径 r= LO1AP = L=O O1 2= 1303mm2l2 - 2 cosaA (l2 - p2 sin2 aA )(l2 - R2 sin2 aA )r2 = l21= (P2 + R2 + l2 ) - 222 O Asin2 aA22 13002 - 2 cos 86 (13002 - 13032 sin2 86)(13002 - 1802 sin2 86)= (13032 + 1802 + 13002 ) - 222 sin2 862= 6408r 80mm曲柄滑块机构中的曲柄半径 r1：1O AHr = l =12= 80 = 40mm 2根据许用压力角调节连杆长 Lab，取 Lab=540mm,然后通过验算得出：lab= lAC H / 2 =sina40sin 25= 96.64西安文理学院本科毕业论文（设计）3.2.6 本节小结通过原始数据计算出辊子的直径 240mm，辊轴转角为 173，摇杆摆角 86，选取辊子长度为 150mm，驱动机构中的机架中心距 p 为 1303mm，曲柄半径 80mm以及连杆长度为 540mm，还讲述了在冲压送料中抬辊装置以及压紧装置、D 为100mm 的超越离合器。3.3 其它零件轴承、紧固零件等其他零件，均按手册选取标准件，详见装配图。本设计的送料机构中设计了一个托物架，以便支撑毛胚材料。需要说明的是，因为本设计所选用的压力计滑块行程次数为 170 次/min，为中速冲压，所以不采用制动装置。但是在高速送料的情况下，由于辊子、材料、传动系统的惯性，会使材料在送料行程终点处的定位精度受到很大影响，故应在辊轴端部装设制动器。制动器的结构形式以闸瓦式应用较为普遍，其结构简单， 容易加工装配。缺点是长期处于制动状态，摩擦损失较大。常用的摩擦材料有石棉或铸铁。其他的制动器有带式和气动式。另外，本送料机构上还加了一个拖物架，起支撑材料的作用，便于辊轴自动送料，其结构如下图图3.5托物架图3.4 轴的设计及校核在本次送料机构中，需要设计 3 根主要的轴，上、下棍轴与大齿轮上的轴， 而下棍轴是最重要的轴，结构复杂、零件较多，所以要对下棍轴进行详细的分析与计算。另外的两根轴作用相对较小，内部结构也相对简单明了，他们只起到让送料过程顺利的作用，所以只对下棍轴做精确的校核。其计算过程如下：在这次设计中，题目并没有对轴做出任何要求，因此我们就按一般的轴来进行计算，通常选用 45 钢作为调质钢，sb = 650MPa,ss= 360MPa 。3.4.1 下辊轴的设计下辊轴的初步计算过程如下：首先得设计下辊轴的整体结构，如下图：图 3.6 轴的结构图下辊轴上的受力图图 3.7 轴的受力图轴上的转矩由上面计算可知T1 = Fb r = 510 60 = 30600N mmF = 2T1 = 2 30600F = 278Nd1t220tF = Ft tanan rcosb= 278 tan 20ocos60oFr = 202NFr1= 278 208 + 224 180266Fr1= 369N画出其弯矩图如下Fr 2= 278 58 + 224 258266Fr 2= 186N在水平面上的弯矩图和计算过程：Ft1 F图 3.8 水平弯矩图= 155 208 + 1200 180266= 155 58 + 1200 158Ft1 F= 933N= 746Nt 2266t 2在垂直面上的弯矩图：图 3.9 垂直弯矩图再将水平面与垂直面的弯矩合成如下：图3.10合成弯矩图其许用应力值 由文献3中 15-4 查得：s0b = 102.5MPa再计算出应力校正系数s-1b = 60MPaa= s-1b = 60 a= 0.59转矩图s0b 102.5其当量转矩为：aT = 0.59 70000aT = 41300N mmaT1 = 0.59 33200,如图再对轴的直径进行校核；aT1 = 21712N mm轴的直径d1 = 28 40mmd1 = 28mmd2 = 21mmd2 = 21 28mm经过详细的计算下棍轴没有超过其所能承受的载荷达到了初步要求。3.4.2 大齿轮轴的设计与校核选取的大齿轮轴的材料为 45 刚,调质处理取 A0 = 105 ，于是得大齿轮轴的最小轴径为dmin= A0= 105 34.83100.71= 38.149mm图 3.11 大齿轮轴示意图大齿轮轴的计算步骤如下：图 3.12 大齿轮受力图首先计算出大齿轮轴受的力如图 3-14，齿轮的受力图，首先要知道转矩则可求出大齿轮轴的圆周力为=550N再能算出大齿轮轴的径向力为=256.47N根据图 3-13，可由此算出大齿轮轴的支撑反力分别为=439.82N根据图 3-14，可由此算出大齿轮轴的水平面反力为=337.18N根据上面的计算，可首先画出大齿轮轴的弯矩图如下图 3.13 大齿轮轴的弯矩图根据上面的计算，受力分析可得大齿轮轴的水平面受力图如下图 3.14 大齿轮轴的水平面受力图则根据图 3-15，可算出大齿轮轴的垂直面反力分别为=809.57N=946.9N根据上面的计算，受力分析可得大齿轮轴的垂直面受力图如下图3.15大齿轮轴的垂直面受力图再综上可画出大齿轮轴的弯矩图如下图3.16大齿轮轴的弯矩图根据文献6中表 16.3 可选得大齿轮轴的许用应力分别为;则可算出大齿轮轴的应力校正系数为=0.64根据上面的计算，可首先画出大齿轮轴的转矩图如下图3.17大齿轮轴的转矩图根据图 3-19，则大齿轮轴的当量转矩分别为aT = 0.64 70000 = 44894N.mm ；aT1 = 0.64 66000 = 42240N.mm再根据上面所有的计算，再得出大齿轮轴的弯矩图如下图3.18大齿轮轴的弯矩图大齿轮轴的轴径 1 为=17.71mm40mm根据计算可知轴径 1 满足要求。大齿轮轴的轴径 2 为=18.07mm26mm根据计算可知轴径 2 也满足要求。综上，大齿轮轴的所有校核都符合要求，则大齿轮轴合格，可用于本次设计的自动送料机构。3.4.3 本节小结通过计算得出上辊轴直径为 d1= 28mm，d2 =21mm；大齿轮轴直径d1=17.71mm，d2=18.07mm；经过详细的校核都符合课题要求。3.5 轴承的计算和校核冲床自动送料装置中一共使用了四个轴承，其中只有下辊轴的轴承受的轴承应力比较大，所以对其他轴承不做校核，下棍轴轴承计算过程如下：下棍轴轴承选用 6232 型深沟球轴承，其轴承数据如下：轴承型号d（mm）D(mm)Cr（N）C0r （N）6232160290112006420对其进行校核它的径向载荷F1r = 844N由前面计算能得到下棍轴的转速n1 = 45r / min下棍轴在轴向上的没有受到任何力，所以F1R = 0N由文献6中表 16-5 得到 e=0.16F1RF1r= 0 ，0e，由文献6中表 16-5 得到X=1.5，Y=0.5由文献6中表 18-1 得到冲击载荷系数 fd = 1.6当量动载荷 PP = fd ( XFr + YFa )= 1.6 (1 844 + 0)= 1204L n计算额定动载荷Cr = P3 h= 1204 16670= 4581由此可得到由于C = 4581N C= 13200N ，所以选用 6232 型深沟球轴承可以满足轴承rr的承受要求。由于下棍轴上是一对轴承所以对另外一个也需要进行校核：它的径向载荷F2 r = 916N由前面计算能得到下棍轴的转速n = 45r / min下棍轴在轴向上的没有受到任何力，所以F2R = 0N由文献6中表 16-5 得到 e=0.16F2 RF2r= 0 ，0e，由文献6中表 16-5 得到X=1.5，Y=0.5由文献6中表 18-1 得到冲击载荷系数 fd = 1.6当量动载荷 PP = fd ( XFr + YFa )= 1.6 (1 916 + 0)= 1476L n29计算额定动载荷Cr = P3 h= 1476 16670= 5142由于C = 5142 N C = 13200N ，所以选用 6232 型深沟球轴承可以满足轴承rr的承受要求。3.6 齿轮的设计及校核本设计中的自动送料机构中有一对齿轮传动，主要带动上辊与下辊之间的运动。这一对齿轮仅仅带动上下辊的传动，一般厚度大于一定值就会影响送料的精度，但本设计所用的材料厚度较薄，其所引起的误差较小，所以忽略其误差，仅用一对齿轮直接传动。本课题对齿轮传动尺寸没有特殊要求，而且不是大批量生产，所以小齿轮用40Cr，调质处理，硬度 238HB268HB，平均取为 250HB，大齿轮用 45 刚，调质处理，硬度 218HB282HB，平均取为 240HB。具体计算步骤如下：3.6.1 初步设计转矩T1由T1 = 33200N mm模数 m取 m=4 .5齿数初取齿数z1 = 53; z2 = 51分度圆直径 dd1 = mz = 4.5 53 = 240mmd1 = 240mmd2 = mz = 4.5 51 = 230mmd2 = 230mm中心距 aa = m( z1 + z2 ) = 4.5 (53 + 51) = 235a=235mm22齿宽 b取 b=50mm取 b 1 =60mmb2 = 50mm转速n1n1 = 120r / min由文献1中图 12-9 中知接触疲劳极限sH limsH lim1 = 710MpasH lim 2 = 580MPa3.6.2 齿轮的校核计算齿轮的圆周运动速度 vv =pd1n160 1000= p 240 120 = 1.508m / s 60 1000齿轮要求的精度的精度等级由 文献1中表 16-8 中得出应取 8 级精度由文献1中图 16-9 中可得出齿轮的使用系数KA = 1.75 ，动载系数 KvKv = 1.1由文献1中式 2-10 得出齿间载荷分配系数 KHaF = 2T1 = 2 33200 = 301.8Nd1t220KAFtb= 1.75 301.8 = 10.56N / mm 100N / mm 50e = 11 a1.88 - 3.2 ( z + z ) cosb12 55= 1.88 - 3.2 1 +1 = 1.1260 Ze = 0.87KH =11Z=e20.872= 1.32由文献1中表 12-11 得到齿向载荷分布系数 KHbKHb= A +B( bd1)2 + C 10-3 bKHb = 1.28= 1.17 + 0.16 ( 50 )2 + 0.6110-3 220220齿轮的载荷系数 K= K A KV KHaKHb =1.75 1.11.32 1.28K = 3.25由文献1中表 12-12 得到弹性系数ZE由文献1中表 12-16 得到节圆区域系数ZE = 189.8ZH = 2.5由文献1中表 12-14 得到接触最小安全系数SH min = 1.5LL由文献1中表 12-15 得到应力循环次数N 其范围在 10 7 N 109 ， 则指数 m=8.78n TmN L1 = Nv1 = 60g nithi i L1N= 6.48 107i=1 Tmax =601 45 24000 18.78L2L1N= N/ i = 6.48 107 / 55 60L 2N= 6.16 107由文献1中图 12-18 得到接触寿命系数Z NZN1 = 1.17ZN 2 = 1.18齿轮的许用接触应力为：s = sH lim1ZN1 = 710 1.17s = 554MPaH1SH min1.5H1s = dH lim 2 ZN 2 = 580 1.18s = 456MPaH 2SH min1.5H 2sH = ZE ZH Ze sH = 243MPa sH 2 = 189.8 2.5 0.87 通过上面的计算结果可以看出，接触疲劳强度适中，齿轮的尺寸没有严格要求，不需要修改其尺寸。再根据齿轮的齿根弯曲疲劳强度验算齿根的重合度系数 Y = 0.25 + 0.75 = 0.25 + 0.75 = 0.68eae1.72由文献1中表 12-10 齿间载荷分配系数 KFaKFa = 1/ Ye = 1/ 0.68由文献1中图 12-14 得到齿向载荷分布系数KFb = 1.3KFa = 1.47齿轮的载荷系数 K = K A KV KFaKFb = 1.75 1.11.47 1.3K=3.68由文献1图表 12-21 齿形系数YFaYFa1 = 2.41由文献1中表 12-22 应力修正系数YSaYSa1 = 1.66YSa2 = 1.67由文献1中图 12-23 弯曲疲劳极限dF limdF lim1 = 600MPadF lim 2 = 450MPa由文献1中表 12-14 弯曲最小安全系数SF minSF min = 2LL由文献1中表 12-15 应力循环次数N 的范围为 3106 N 1010 ,则指数 m=48.91n TmN L1 = Nv1 = 60g nithi i i=1 Tmax =601 45 24000 149.91L1N= 6.48 107经过上面的计算原齿轮的应力循环次数是满足要求的。L2L1N= N/ i = 6.48 107 / 60 55L 2N= 6.16 107由文献1中图 12-24 弯曲寿命系数YNYN1 = 0.94YN 2 = 0.95由文献1中图 12-25 齿轮的尺寸系数YXYX = 1.0则齿轮的许用弯曲应力sF1 = sF lim1YN1YXSF min= 600 0.94 1 2sF1 = 282MPasF 2 = dF lim 2YN 2YXSF min= 450 0.95 1 2dF 2 = 214MPaF1经过检验与计算 s= 2KT1 YYYbd1mFa1Sa1 e= 2 3.68 33200 2.411.66 0.68 50 220 4sF1= 21.3MPa dF1 s= sYFa2YSa2= 21.3 2.4 1.67F 2F1 YFa1YSa12.411.66sF 2 = 21.4MPa sF 2 由上面计算结果得知齿轮在传动过程中没有严重过载，设计的齿轮的结构简图如下图：图 3.19 齿轮结构简图3.6.3 本节小结由上面的计算齿轮的参数模数 m=4.5 齿数 z1=53， z2=51 分度圆直径d1=240mm，d2=230mm，齿宽 b=50mm，b1=60mm，b2=50mm，转速 n=120r/min， 经过严密的校核计算两齿轮都是合格的。3.7 键的设计和校核键是标准件，用来实现轴上轴向固定和周向固定。此次设计采用了四个键， 分别是 3 个普通平键和 1 个圆头楔键。3.7.1 平键 1 的设计和校核图3.20 平键连接受力图选择键连接的类型和尺寸一般来说，精度为 8 以上的齿轮具有定心精度要求，应选用平键连接。由于齿轮不在轴端，故选用圆头普通平键（A 型）。校核键连接的强度键，轴和轮毂的材料都是钢，由文献12中表 6-1 得：平键 1 传递的转距为 70，轴径 26mm。由文献12中表 11-6 可得键的截面尺寸为：宽度 b=6mm，高 h=9mm，选键长为 18mm。键的接触长度=l-b=22-8=14mm。由文献6表 7.1 取许用挤压应力，7.1 型组合可传递的扭矩因此，平键 1 的挤压强度足够，设计的关键符合要求。3.7.2 平键 2 的设计和校核平键 2 的转移距离为 33.2，轴径为 48 毫米。由文献12中表 11-6 可得键的截面尺寸为：宽度 b=16mm，高度 h=10mm，选键长为 48mm。键的接触长度=l-b=45-14=31mm。由文献6表 7.1 取许用挤压应力，由式 7.1 得联结所能传递的转矩因此，平键 2 的挤压强度足够，设计的关键符合要求3.7.3 平键 3 的设计和校核平键 3 传递的转距为 36.8，轴径 40mm。由文献12中表 11-6 可得键的截面尺寸为：宽 b=13mm，高 h=8mm，选键长为 42mm。键的接触长度=l-b=45-12=33mm。由文献6表 7.1 取许用挤压应力，由式 7.1 得联结所能传递的转矩因此，平键 3 的挤压强度足够，设计的关键符合要求。3.7.4 本节小结三个键的数据结果为平键 1 的轴径为 26mm；宽 b=6mm，高 h=9mm，键长为 18mm。平键 2 的轴径为 48mm，宽 b=16mm，高 h=10mm，选键长为 48mm。平键 3 轴径 40mm 宽 b=13mm，高 h=8mm，选键长为 42mm。4润滑与密封4.1 润滑润滑剂选择原则的选择原则是，轴承转速越高，摩擦热越大，粘度越大的润滑油越高，工作锥中的润滑脂越大，低速时反之也越大。润滑脂和润滑油的 DMN 值列在适合于表面油脂润滑和油润滑的 DMN 值中。在运行过程中，轴承的温度由于摩擦和热而迅速增加。每个润滑剂具有一定的温度范围，温度是影响轴承精度的一个因素。因此，在工作温度高的情况下，应选择粘度大、闪点高的润滑脂。建议轴承负荷的大小在温度范围内适用于油脂，可大大影响油膜的形成。载荷越大，油膜形成的可能性越小。因此，当载荷较大时，应选用粘度较大或工作锥度较大的润滑油作为较小的润滑脂。在承受冲击载荷时，在工作环境中选用粘度较大或润滑脂较少的润滑脂是合适的。当空气潮湿，灰尘较多时，当密封装置简单时，应选择不易溶于水中的钙基脂肪；环境空气干燥，水少，然后在垂直方向安装钠基润滑脂的安装状态。或倾斜状态。除密封外，斜轴上的轴承易于排水。应选用粘度稍大的润滑油或工作锥体稍小的润滑脂，滴注润滑，循环润滑，喷射润滑。本设计主轴转速为 170r/min 所以采用脂润滑比较合理，大概每 360 小时需要人工手动换一次润滑剂，以保证齿轮的齿面的清洁从使齿轮能正常运转。轴承润滑采用固体的黄油润滑，每隔 240 个小时手动枪加一次油，保持轴承良好的润滑特性。4.2 密封轴承的密封方法可分为接触式密封及非接触式两类 接触式密封有毡圈密封、密封圈密封等。非接触式密封具有轴向密封、径向曲线密封、油槽密封和密封环密封。功能：防止灰尘、水等杂物进入轴承，并防止润滑油的损失。本次设计中需要密封的主要结构是轴承，主要使用毡圈密封的形式密封。在轴承盖上设置梯形槽，根据标准将毛毡制成圆形或带状，并放置在梯形槽中以紧密接触轴。毡环密封主要用于油脂润滑，结构简单，摩擦系数大，仅用于滑动速度小于 4 5M/s，工作温度不高于 90。参考文献1 成大先，机械设计手册D.化学工业出版社，2002，61-67.2 焦连岷.冲床的数控改造及全自动送料装置的研制D.南京：南京理工大学，2007.3 王振宁，张学良.冲压机自动送料机构气动系统及 PLC 控制J.液压与气动，2003（10）:49-50.4 徐刚，鲁洁，黄才元.金属板材冲压成形技术与装备的现状与发展J.锻压装备与制造 技术，2004（4）：16-22.5 张新华，俞震初.冲床自动送料机的原理与设计J.锻压技术，1993,18（5）：46-49.6 张新华，鲁志康，赵建跃.冲床自动送料机的 PLC 控制与设计J.锻压技术，2000，25（2）：44-46.7 鲁世红，金龙，杜超.卷板机自动送料技术的现状及发展趋势J.锻压技术， 2017,42(7):1-5.8 姜奎华，冲压工艺与模具设计J.机械工业出版社,2000,9(5):21-279 中国机械工程学会锻压学会.锻压手册J ,机械工业出版社,1993,16(3):36-41. 10黄继昌、徐巧鱼、张海贵、范无保、季炳文 .实用机械机构图册J,人民邮电出版社 ,1996,41(15):19-23.11华大年,机械原理J,高等教育出版社,2000,11(7):9-13.12 王昆、何小柏、汪信远,机械设计基础课程设计J,高等教育出版 社,1995,23(19):25-29.13 姜奎华,冲压工艺与模具设计J,机械工业出版社,2002,(5):46-52. 14杨玉英,工程制图J,纺织工业出版社,1997,19(2):28-36.15上海技术革新展览会,实用冲压技术J,上海科学技术出版社,1982(9):22-29. 16甘永立,几何量公差与检测J,上海科学技术出版社,2001,27(12):38-45.总结本次设计主要学习了机械设计过程中的设计方法、流程及关键的原理，对结构设计有了一定的接触与认识，也了解到了冲压生产的工艺过程，设计的准则和结构的优化性的综合运用，受益匪浅。通过毕业设计，使自己对学习的各门课程有了进一步的理解，知识得到了系统化同时自己在这次毕业设计中，学习到了的设计知识，但在基础环节上存在许多不足之处还需要不断学习和完善，以适应学习和应用的紧密结合。特别是，在机械结构设计上应使零部件相对于整体结构更趋于优化和实用总之，通过这次毕业设计到现场调察研究，收集资料，阅读文献，设计方案， 分析比较，在综合能力上得到了训练，我觉得是对个人综合能力的培养，这对今后的工作和学习积累了宝贵的经验。致谢为期一学期的毕业设计终于走到了尽头，也就意味着我们将告别大学时代的生活，这期间的过程是令人烦恼而又感到充实的，多少次努力却不见成效，多少个夜以继日的操劳，最后换来一次完美的句号。这期间我感谢我的指导老师和陪伴我的同学，在老师不厌其烦的指导下我顺利的完成了学业任务，为我大学生活画上圆满的句号。这次毕业设计中最让我获益的是，增长了独立自主学习的能力。当我一筹莫展时，我首先去图书馆借书。在那些书中我知道了冲床是什么，它自动送料的意义，我应该怎样开始着手。虽然过程很辛苦，但我没有放弃，这是让我最值得骄傲的地方。在以后的学习和生活中，我肯定会面临更过更大的困难，那是没有老师同学帮助我，我得靠自己。我必须得选择坚持，放弃是懦弱的。所以我现在就应该不惧困难，做好毕设。这次毕业设计运用了很多专业知识，很多是大二大三所学。好些知识已经忘记，但我没有气馁，我就去查阅了许多文献和书籍。这些都锻炼了我的自学能力和动手实践能力，获得了很大的成就感。但我知道我的知识还不够，还需要更多的学习。我也对机械这个行业有了更深的了解，产生了更大的趣味性。我更感受这个专业的重要性，需要运用于实践。如果用心去做，就会发现机械这个行业的趣味性，并不是那么枯燥乏味。未来我还要面临更多的困难和挑战，而我也不会像在学校有这么多的帮助。所以我就更需要多学习多经历。这次毕业设计就恰好的达到了锻炼自己的目的， 我很感谢有这样的一次机会，也为我以后的工作和学习奠定了一个非常好的基 石，以后能取得更大的进步。再一次的感谢老师与同学的陪伴，希望大家今后一切顺利。39附录 A 英文文献翻译Reconfigurable manufacturing systems: Principles, design, and future trendsAbstract :Reconfigurable manufacturing systems (RMSs), which possess the advantages of both dedicated serial lines and flexible manufacturing systems, were introduced in the mid-1990s to address the challenges initiated by globalization. The principal goal of an RMS is to enhance the responsiveness of manufacturing systems to unforeseen changes in product demand. RMSs are cost-effective because they boost productivity, and increase the lifetime of the manufacturing system. Because of the many streams in which a product may be produced on an RMS, maintaining product precision in an RMS is a challenge. But the experience with RMS in the last 20 years indicates that product quality can be definitely maintained by inserting in-line inspection stations. In this paper, we formulate the design and operational principles for RMSs, and provide a state-of-the-art review of the design and operations methodologies of RMSs according to these principles. Finally, we propose future research directions, and deliberate on how recent intelligent manufacturing technologies may advance the design and operations of RMSs.Keywords: reconfigurable manufacturing systems, responsiveness, intelligent manufacturing1IntroductionThe world of manufacturing has changed dramatically in the last 100 years in response to economic and social circumstances. Driven by different requirements in various periods, manufacturing technologies and new paradigms have been introduced to address economic challenges, and respond to social needs. Facing the requirement of cost-effectiveness, Henry Ford invented the moving assembly line in 1913, which began the mass production paradigm. In the 1970s, the Japanese manufacturing industry started formulating lean manufacturing principles, and since then consistent product quality has been a major focal point. In the late 1970s, the development of computer numerical control (CNC) machines facilitated the creation of flexible manufacturing systems (FMS), which enabled producing a variety of products on the same manufacturing system 1.Globalization that began in the 1990s transformed the competitive landscape. Manufacturing companies started facing unpredictable market changes, including rapidly varying product demand, and frequent introduction of new products. This made the design of manufacturing systems for new factories a major challenge, because it impacts the factory performance for many years after the factory design. It became essential that new factories should possess a new type of manufacturing system A system designed for rapid responsiveness to unforeseen market surges and unanticipated product changes.In response to this challenge, in 1995, Dr. Koren proposed designing factories with new system architecture that he called “reconfigurable manufacturing system.” The RMS has an open system architecture that enables adding machines to existing operational systems very quickly, in order to respond (1) rapidly, and (2) economically to unexpected surges in market demand 2. Utilizing RMS enables building a “live” factory that its structure changes cost-effectively in response to markets and customers needs, so it can keep supplying products at competitive pricefor many years after the factory design.In 1996, Dr. Korens proposal to form an “engineering research center for reconfigurable manufacturing systems” (ERC-RMS) was approved by the U.S. National Science Foundation (NSF). The ERC-RMS was established at the University of Michigan with a grant of 33 million USD for 11 years from NSF. Matching funds of 14 million USD were granted by industry and the State of Michigan. The center created the RMS science base and invented RMS technologies that were implementedin the U.S. automotive and aerospace industries, enhancing thereby the industry competitiveness.It is worthwhile to note that the State of Michigan is home to notable inventions in manufacturing. In 1913, the first moving assembly line, invented by Henry Ford, was installed at the Ford Highland Park plant in Michigan. The second breakthrough invention was numerical control that was invented by John Parsons 3 in his company in Traverse City, Michigan. The recent innovation is the RMS. RMS is a new type of manufacturing system that can change its system structure and resources rapidly and cost-effectively, in order to possess “exactly the capacity and functionality needed, exactly when needed.” Figure 1 illustrates how the inventions from Michigan have transformed the landscape of manufacturing paradigms.The ERC-RMS has defined the key characteristics for RMS, and invented patents and software packages that have provided the basis for developing new reconfigura-tion technologies. The developed technologies have been successfully implemented in U.S. automotive companies Ford, General Motor, and Chrysler which have increased their system responsiveness 4 and created substantial economic value for these firms 5. RMS is not only an open-architecture manufacturing system that can respond to the challenges of globalization 6, but also one that boosts productivity, enhancing thereby the competi-tiveness of manufacturing enterprises. RMS can also achieve agility and sustainable manufacturing 7,8.In this paper, we formulate the principles that guide the design and operations of RMS. According to these principles, we review and evaluate the state-of-the-art RMS design issues presented in the literatures. Possible future developments of RMS are discussed as well.Fig. 1Manufacturing inventions initiated in Michigan2RMS characteristics and principlesThe three main goals of all manufacturing systems are cost, product quality, and responsiveness to markets. Respon-siveness is achieved by designing manufacturing systems for upgradable capacity and modifiable functionality. Comparing RMS with other types of manufacturing systems from the perspective of these goals, highlights the advantages of RMS.2.1 RMS combines advantages of dedicated lines and flexible systemsIn the last decades of the 20th Century the manufacturing industry utilized two types of common manufacturing systems: Dedicated manufacturing lines (DMLs) and FMSs. DMLs are designed to enable mass production of a specific product at a very low cost and very high throughput. FMSs are designed to enable production of any product (confined within a geometric envelope), but compared with DMLs their throughput is very low.The DML is designed with fixed automation that produces the companys core product at a very high rate. During the production, many tools can operate simultaneously on every machine in the line, leading to extremely high system throughput. The DML structure is fixed and cannot be changed neither to increase the throughput nor to produce a different product. If the market requires higher throughput, the DML cannot supply the full demand and the firm loses sale opportunities and consequently may lose market share. If the market requires a different product, the DML is useless and must be scrapped.By contrast, FMSs possess general flexibility that can produce a variety of products, but their production is by far more expensive than producing on DMLs. The FMS consists of general-purpose CNC machines and other forms of programmable automation. By contrast to a DML machine on which many tools operate simultaneously, each CNC machine uses a single tool during its operation. Therefore, the throughput of FMS is by far lower than that of DML (for the same investment cost). The main drawbacks of FMS are the high investment cost (on both machinesand tooling) and the relatively low throughput. Due to the high investment on CNC equipment, and the large number of cutting tools in the system, producing high volumes on FMS becomes a significant economic issue.The main advantage of RMS is that its functionality and capacity can be changed (1) rapidly and (2) cost-effectively. It is a feature that neither a DML nor an FMS possesses. The throughput of RMS is higher than the FMS throughput, but it is lower than that of a DML (for the same investment cost). The RMS is designed around producing a family of parts (e.g., cylinder heads, which are manufactured in reconfigurable machining systems) or products (e.g., engines, which are assembled in reconfigurable assembly systems), so its flexibility is by far higher than that of aDML. A thorough comparison of these three types of manufacturing systems is presented in Ref. 9, and their comparison with adjustable manufacturing systems is presented in Ref. 10.2.2 Core characteristics and principles of RMSThe RMS is defined as follows: An RMS is designed at the outset for rapid change in structure, as well as in hardware and software components, in order to quickly adjust its production capacity and functionality within a part family in response to sudden changes in market or regulatory requirements.The RMS possesses six core characteristics that are summarized in Table 1. The six core RMS characteristics reduce the time and cost of reconfiguration,thereby enhancing system responsiveness. They are widely implemented today in the automotive, aerospace, food and beverage industries in the U.S. Based on these RMS core characteristics, the following RMS principles are formulated.RMS principles:1) Design manufacturing system capacity for cost-effective adaptation to future market demand (scalability);2) Design the manufacturing system for adaptation to customers new products (convertibility);3) Design optimally embedded product quality inspection into manufacturing systems (diagnosability);4) Design the manufacturing system around a product family (customization); 5)Maximize system productivity by reconfiguring operations and reallocating tasksto machines;6)Perform effective maintenance that jointly maximizes the machine reliability and the system throughput.The first four are system design principles that utilize the characteristics of “modularity” and “integrability” to enable cost-effective design. For example, at the system level, every machine is a module and the integration is done with material handling systems (e.g., a gantry or a conveyor). Principles 5 and 6 are system operational principles that improve the system productivity and reliability. Based on Principle 5, the ERC-RMS created system-balancing software that was implemented in 22 factories of General Motors and Chrysler and generated substantial savings. For example, Mr. Brian Harlow, VP Chrysler reported: “By using the ERCRMSline-balancing software, Chrysler succeeded in saving 10% of the operating costs on engine assembly lines in the Mack Avenue Engine Plant in Detroit, which is extremely significant.”Mathematical definitions have been proposed for the RMS key characteristics 11, especially for scalability 12, convertibility 13, and an integrated multiattribute reconfigurability index 14. These characteristics and principles are applied to the design of different types of reconfigurable manufacturing systems, including machining systems, fixturing systems, assembly systems, and material handling systems 15,16, by using various models 1720 and methodologies 21,22.2.3 Examples of reconfiguration technologiesIn order to illustrate the RMS core characteristics, three examples of reconfiguration technologies machine, inspection, and system are presented below.2.3.1 Reconfigurable machine toolsReconfigurable machine tools (RMTs) are designed for a specific range of operational requirements, and can be rapidly converted from one configuration to another. The design of the RMT is usually focused on a specific part family, and should be rapidly adjustable to changes in its structure and/or operations to manufacture various parts of that part family. The world-first patent on RMT was issued in 1999 23.Figure 2(a) shows an arch-type RMT that was built by the ERC-RMS and exhibited in 2002 at the International Manufacturing Show in Chicago. It was designed to drill and mill on inclined surfaces in such a way that the tool is perpendicular to the surface. This RMT is reconfigurable to five angular positions of the spindle axis ranging from15 to 45 at steps of 15, and the reconfiguration from one angle to another takes less than 2 min. It was utilized to mill and drill engine blocks at angles of 30 or Reconfigurable inspection machineThe reconfigurable inspection machine (RIM) represents a class of in-process inspection machines that can be reconfigured to fit the inspected part geometry. The world-first patent on RIM was issued in 2003 24.Figure 2(b) shows an example of an RIM that is composed of a precision conveyor moving the part along one accurate axis of motion within an array of electro-optical devices, such as digital or line scanning cameras, and laser-based sensors. Depending on the part that is being measured, the location and number of sensors in the RIM canbe reconfigured to fit the geometry of the inspected part. The RIM depicted in Fig. 2(b) was configured to measure cylinder heads. On one side of the part there are two laser sensors; on the other side there are additional three laser sensors as well as an accurate computer-vision system.In 2006, General Motors installed an RIM that was developed by the ERC-RMS at its engine plant in Flint, Michigan. This RIM utilized machine vision to efficiently detect small surface pores ( 1 mm) on engine blocks at the line speed to inspect each part. Utilizing the RIM has significantly improved the quality of the product and greatly reduced the number of recalls because of noisy engines.Fig. 2 Reconfiguration machine tool (RMT) and reconfigurable inspection machine (RIM) developed at the ERC-RMS. (a) RMT; (b)RIM2.3.3 Reconfigurable manufacturing systemA typical RMS integrates CNC machines and several RMTs that are utilized to manufacture a family of products, as well as product quality inspection machines that inspect the product during its manufacturing (i.e., not only at the end of the production line). The structure of an RMS is easily changeable to enable adding more production resources. The option of reconfiguration by adding production resources should be planned at all levels,hardware, software and controls, to enable adding machines, in-line inspection stations, gantries, etc. The world-first patent on RMS was filled in 1998 25.The Ford Windsor Engine Plant that was designed and built in 19982000 contains about 120 CNC machines that are arranged in a reconfigurable system architecture that consists of 20 stages, with 6 machines per stage (as shown in Fig. 3) 26. Ford Motor Co. called this system: “Flexible, reconfigurable manufacturing system.” Flexible because the CNC machines can produce multiple product variants.Fig. 3 Ford Winsor Engine Plant with CNC machines 26Note that, at the system level, each CNC machine is a module, and its function can be converted when a new type of part is required to be manufactured by the system. At each stage of the system, there are multiple parallel CNC machines that are integrated into the system by using gantries to load and unload the CNCs. Furthermore, all the stages in the system are integrated into one large system by overhead gantries that transport parts between the stages. This system possesses the characteristic of diagnosability by including in-line inspection stations that are located next to critical machining stations. This system is scalable, namely, it is easy to add machines to the system to increase the system capacity. Actually, since 2000, the Ford plant went through three reconfigurations in which capacity was added. Note that, if the CNCs in some stages were replaced by RMTs that can process a certain part family, then the customization characteristic would be implemented.The RMS principles are widely used in the design of reconfigurable machines 27, machining systems 15, and assembly systems 16. Next, we review the related research problems in system-level design and operations. Different from other general reviews 11,15,16,22, this paper reviews the design and operations of RMSs according to the principles that we have formulated in Section 2.2.3 Design and operations of reconfigurable manufacturing systemsThe designer of a manufacturing system has to determine:1)The system configuration the way that machines are arranged and interconnected in the system;2) the equipment the number and type of machines, the material handling system, and the in-line inspection equipment; 3) the process planning assigning operations to each machine in the system.3.1 Selecting the system configurationThe performance (e.g., throughput) and characteristics (e.g., scalability) of the manufacturing systems signifi-cantly depend on the system configuration 28. We elaborate here on three types of manufacturing system configurations: Serial production lines, parallel systems, and reconfigurable manufacturing systems. The system type should be carefully determined at the system design stage because once determined, it cannot be changed in the future.Depending on the business goals of the manufacturing enterprise, four major performance metrics should be considered and prioritized when selecting the system configuration:1) Investment cost;2) Throughput resilience to machine failures;3) Speed of responsiveness to markets (i.e., increasing throughput to match future higher demand);4) Level of consistency in product quality in mass production environment.Traditional configurations of manufacturing systems are mainly of two types: Pure serial lines that consist of dedicated or flexible machines, and pure parallel systems that are composed of CNC machines. The drawbacks of serial machining lines are the high sensitivity of their throughput to machine failures, and the lack of respon-siveness to changing markets. The parallel configurations are not sensitive to machine failures, and can easily increase their throughput by adding more machines in parallel. However, parallel configurations are very expen-sive because: 1) Each machine must be capable of performing all the production tasks, which significantly increases the capability of each machine and consequently its cost, and 2) the total tooling cost in the system is expensive (the tool magazine of each machine must include all tools needed to produce the part). Because of these drawbacks, parallel systems are rarely found in practice.For large machining systems, there are two types of configurations that are commonly used in industry: 1) A configuration that consists of several serial linesarranged in parallel (SLP), and 2) RMS configuration that consists of several stages, where each stage consists of multiple parallel identical machines (usually CNCs or reconfigur-able machines). The schematic layouts of the SLP and RMS configurations are shown in Fig. 4. Both systems in Fig. 4 have the same number of machines.TheprincipaldifferencebetweenSLPandRMS configurations is that RMS has crossover connections that enable operating the three machines in each stage in a parallel mode. In practice, a gantry that operates in each stage enables these connections. The gantry loads and unloads parts to or from each machine in that stage. The cost of these gantries makes the RMS more expensive than the SLP configuration. However, the two major advantages of RMS are: 1) Resources (e.g., machines) can be added very quickly and cost-effectively, enabling thereby high speed of response to changing markets; 2) if the gantries availability is higher than the machine availability, the throughput dependency on machine failures in RMS is smaller than that in serial lines.Freiheit et al. 29 developed a model that compares the throughput of SLPs and RMSs. It proves that the RMS configuration has a higher throughput for large systems (i.e., systems with more stages or more machines per stage). Gu 30 extended the analysis to systems with buffers, and showed that RMS is advantageous when small buffers are added to the system. In addition to throughput, Koren et al. 31 compared the performance of SLP and RMS configurations from other perspectives, including cost, responsiveness, and consistency in product quality.Moreover, in an RMS configuration, each stage may not necessarily have an identical number of machines. There-fore, practically, for the same number of machines there are more RMS configurations than SLP configurations. Various complex optimization problems have been for-mulated for selecting the optimal RMS configuration. For example, Youssef and ElMaraghy 32 proposed a procedure for modeling and optimization of multiple-aspect, multi-part RMS configurations, with several future reconfiguration plans considered. Dou et al. 33 built an optimization program that determines the system configu-ration, the type of machines, as well as the operations assigned to each stage. Goyal et al. 34 developed algorithms to choose the optimal RMS configuration based on the reconfigurability and operational capability of RMTs.Note that for reconfigurable assembly systems, determining the optimal configuration is more complicated than that in reconfigurable machining systems.49Webbink and Hu35studied how the assembly system configuration can be generated given the number of assembly stations. Benka-moun et al. 36 reviewed the main strategies dealing with the variety and product change in assembly system design.3.2 Utilizing the RMS principles to design and operate the systemWe elaborate below on how the six RMS principles are utilized to optimize the system design and its operations.Fig. 4 Schematic layout of (a) SLP configuration and (b) RMS configuration3.2.1 Capacity planning by utilizing Principle 1Capacity means the maximum number of products that a manufacturing system can produce annually. Designing the capacity of a new system is a major challenge in an environment of future unpredictable market changes. If in the future the market demand becomes lower than the system capacity, machines will stay idle, which conse-quently causes a huge capital loss. And if the future demand is higher than the capacity, the firm will lose sale opportunities, and consequently may lose market share.To build a factory with a large manufacturing system may take two to three years, and then it is operational for 12 to 25 years. The designed capacity of the new manufacturing system is critical to the factory future profitability, but the enterprise business unit provides its forecasting for a projected demand for the next years (e.g., up to 8 years) with statistical data. How can this forecasting be utilized to design an optimal manufacturing system?The RMS provides an economical response to this challenge. The RMS is built according to Principle 1: Design manufacturing system capacity for cost-effective adaptation to future market demand. Various models have been developed todetermine the optimal capacity at the system design stage, as well as the potential capacity expansion strategies in the future. For example, Narongwanich et al. 37 investigated the optimal capacity portfolio of a firm that utilizes two types of systems a dedicated manufacturing system (DMS) and an RMS. As Ford VP, Mr. Krygier, reported in Ref. 27, Ford utilized their models in justifying purchasing an RMS for the new Windsor Engine Plant. Deif and ElMaraghy 38 considered the capacity-planning problem for an RMS where the cost function incorporates the physical capacity-based cost as well as the cost associated with the reconfiguration process. Gyulai et al. 39 studied the capacity-planning problem for an assembly system in order to decide whether a certain product should be assembled on a dedicated or on a reconfigurable line, or it should be outsourced. Renne40 developed a genetic algorithm and Monte Carlo simulation based model to design a hybrid manufacturing system composed of dedicated, flexible and reconfigurable machines. Asl and Ulsoy 41 developed the capacity investment and adjustment policy for a reconfigurable manufacturing system by using stochastic optimal control and feedback control approaches, where the capacity can be added to the system or removed from the system at a cost. Spicer and Carlo 42,43 simultaneously considered the investment and operational costs for an RMS by considering system reconfiguration, and developed heuris-tic policies to determine the optimal system configurations at the design stage.3.2.2 Functionality planning by utilizing Principle 2In addition to the capacity, the system functionality is another critical factor in developing system reconfiguration policies. The system functionality focuses on changing the system from manufacturing one product to another of the same product family. It requires consequent changes in the process planning and the configuration.The RMS is designed according to Principle 2: Design manufacturing systems for adaptation to customers new desires. This principle requires designing systems with the core characteristic of convertibility, which can effectively transform the RMS to produce a new product. Maier-Speredelozzi et al. 13 pioneered the mathematical definition of the convertibility measure for manufacturing systems.The RMS may contain both dedicated resources for specific products, as well as flexible resources for multiple products. Van Mieghem 44 studied the optimal invest-ment ratio between dedicated and flexible capacities, where the “dedicated” and “flexible” capacity in this research means the capacity that can be used to produceone specific product or multiple products, respectively; namely, this study is from the product viewpoint. Ceryan and Koren 45 extended the model to a multistage problem and studied the optimal investment strategy for a system that manufactures two products. Matta et al. 46 formulated the reconfiguration problem of production systems by using a dynamic programming approach, and proposed the optimal reconfiguration policy to react to product changes. Bryan et al. 47 developed a mathematical model to study the co-evolution of product and the manufacturing system.Note that, in the capacity and functionality planning problems of RMSs, ramp-up is an important consideration when developing system reconfiguration policies. It is defined as “the time interval it takes a newly introduced or just reconfigured production system to reach sustainable, long-term levels of production, in terms of throughput and part quality, considering the impact of equipment and labor on productivity” 2. The RMS has unique characteristics that allow high-resolution scalability and rapid respon-siveness, which reduce the ramp-up period. Matta et al.48 investigate the impact of ramp-up period on the reconfigurable policy, by considering both capacity expansion and reduction. Niroomand et al. 49 built a mathematical programming model to discuss about how different reconfiguration characteristics (e.g., the time needed for reconfiguration and the ramp-up period) impact the design of manufacturing systems.3.2.3 Maintaining product quality by utilizing Principle 3Maintaining product quality is a critical consideration when designing manufacturing systems. Each machine has a tolerance, and the dimensional deviation from the norm accumulates as the part moves along the system. In a serial line there is only one production route, and therefore the range of the dimensional deviation is small. The number of production routes in a serial-lines-in-parallel configuration is equal to the number of lines, which is small. However, in the RMS, the number of possible production routes is very large. Assuming there are n stages, and m parallel machines in each stage, there are mn production routes. The RMS built at Ford Windsor Engine plant has 6 machines in a stage and about 20 stages, so that the number of possible routes is huge (i.e., around 3.6 1015). The designer should be aware of the huge number of routes issue in RMS, and pay prime attention to the product quality issue.The large number of production routes causes two problems. First, it increases of the variation of the product dimensional quality. Second, if there is any abnormal machine in the system, it is extremely difficult in the RMS case to trace that machine by just inspecting the quality of the final product. Therefore, the system designer should pay attention to the quality of the products in an RMS by implementing Principle 3: Design optimally embedded product quality inspection into manufacturing systems. If there are any quality issues detected by in-line inspection stations, the system should be able to locate the root-cause quickly, and take suitable actions (e.g., preventive maintenance).Stream-of-variation (SoV) 50,51, a method based on the state-space model that is utilized in control system, has been developed to systematically analyse the quality propagation in multi-stage manufacturing systems, in order to identify the root-cause and reduce the product variation. Monte Carlo simulation methods can also be used to analyze the product variation 52. Based on the SoV model, Kristianto et al. 53 developed a two-stage programming model to investigate the reconfiguration problem of RMS. In addition to the SoV model, Abad et al.54 developed an algebraic expression to represent the quality stream in more complex configuration, such as mixed-model assembly systems.In order to measure the product quality in-line, it is recommended to integrate RIMs into the RMS. When designing the system configuration, experts should decide on the critical locations where RIMs should be installed. Moreover, a return conveyor can be added into the RMS to route back parts that need to be reprocessed. Figure 5 illustrates the design of an RMS with inspection stations and a return conveyor. Optimizing the number and location of the inspection stations is an important issue that should be investigated in the future. On the one hand, reducing the frequency of inspection decreases the system capital cost; on the other hand, increasing the number of in-line inspection stations reduces the number of parts rejected because of quality loss.3.2.4 Formulating a product family by utilizing Principle 4In order to reduce the cost and improve the system efficiency, RMSs are designed according to Principle 4: Design the manufacturing system around a product family. For utilizing RMSs, products are grouped into families, each of which requires its own system configuration. The system is configured to produce one product family. The system can produce every product within this product family with high efficiency,and it can be done without reconfiguring the system (or with simple alternation). Once the current product family is phasing out, the system is reconfigured to produce another product family, and so forth 55. Therefore, finding the similarity between products and forming the right product family improve the system efficiency.A product family consists of products that share similarities. In order to formulate the product family, a similarity index could be established to measure the similarity between different products. Kimura and Nielsen56 developed a framework for the relationship between product functionality and manufacturing resources. Their framework yields to a design method for product family structure, which realizes the required product functional variety with efficient utilization of manufacturing resources. Abdi and Labib 57 proposed a novel “reconfiguration link” that incorporates the tasks of determining the product families and selecting the appropriate family at each configuration stage. An analytical hierarchical process (AHP) model is used while considering both market and manufacturing requirements, which is illustrated by a case study in Ref. 58. Galan et al. 59 also used the AHP method to build the similarity matrix among different products, by considering the product requirements such as modularity, commonality, compatibility, reusability, and demand. Based on the similarity matrix, the average linkage clustering algorithm was applied to formulate the product families. In addition, an analytical network process (ANP) model is proposed by Abdi 60 to incorporate all the outlined decisive factors and major criteria and elements influencing the product family formation and selection. Battaa et al. 61 developed a combinatorial optimization problem for part family formation and configuration design in reconfigurable machining systems.Fig. 5 A futuristic RMS configuration with RIMs and a return conveyorOn the operational level, operation-scheduling problems are studied that optimize the sequence of producing different products, in order to improve the system efficiency. The operational sequence should also be considered in analyzing the similarities of products and determining the product families. For example, Goyal etal.62 developed an operation sequence based BMIM (bypassing moves and idle machines) similarity coefficient that utilizes several concepts in set theory, such as the longest common subsequence (LCS), and the minimum number of bypassing moves and the quantity of idle machines. Wang et al. 63 further combined LCS and the rest of the operation to construct the shortest composite super-sequences. These similarity coefficients are used as the basis for part clustering and family formation.In addition to machining systems, the concept of product family formation has been applied to assembly systems64 and disassembly systems Process planning and line balancing by utilizing Principle 5Process plan specifies the components and operations that are needed to manufacture a workpiece into a part or a product. The process planning in an RMS requires the consideration of multiple product families, or multiple product generations.Effective process planning can reduce the reconfiguration cost, improving thereby the system efficiency. For example, Azab and ElMaraghy 66 proposed the idea of “reconfigurable process planning,” and formulated it as an integer-programming problem. Azab et al. 67 used simulated annealing method to sequence the machining operations in order to reduce the system idle time. Bensimaine et al. 68,69 investigated the process-planning problem in RMS by developing optimization algorithms for different objectives.Each time that the system has to manufacture a new product, a new process plan is needed. It includes the sequence of all operations needed to complete the product. The operations should be distributed among the machines in the system in order to balance the system according to Principle 5: Maximize system productivity by reconfigur-ing operations and reallocating tasks to machines. A new process plan is needed each time that machines are added to the system to increase the system capacity. The objective is to make as close as possible equal operation times on each machine or stage in the system in order to balance the system, which maximizes the system throughput.Transfer line balancing problem has been extensively studied in the literature. In an RMS environment, various models and methods have been developed to formulate and solve the line-balancing problem. For example, Wang and Koren 12 developed an optimization algorithm based on genetic algorithm (GA) that determines simultaneously at which stage to add machines, and how to rebalance the modified system (by shifting operations among stages) in order to maximize throughput. Thisalgorithm was adopted by General Motors to be used in practice. In industrial utilizations several practical constraints were imposed, such as the tasks precedence relationship, and the product facets on which a specific operation is needed. Borisovski et al. 70 also used the GA method as well as a set-partitioning model 71, to solve the line-balancing problem in RMS, with the objective of minimizing the set-up times. In addition, Essafi et al. 72 studied the line-balancing problem in an RMS consisting of mono-spindle head CNC machines. Makssoud et al. 73 developed an optimization problem in order to minimize the reconfiguration cost of an RMS. They formulated the problem as a mixed integer-programming problem in order to consider the compromise between introducing new equipment and reusing old one. Delorme et al. 74 studied the line-balancing problem in RMS to deal with the trade-offs between the cost and productivity.Moreover, the control system needs to be developed for enabling task reallocation and system rebalancing. For example, da Silva et al. 75 proposed a control architecture based on the Petri nets, service-oriented architecture, and holonic and multi-agent system techni-ques, in order to design the control system in an RMS that considers reconfiguration in functionality and production capacity.3.2.6 Optimizing maintenance operations by utilizing Principle 6In order to improve the system reliability and the product quality, maintenance needs to be performed. According to an ERCRMS survey conducted at the U.S, and European automotive and machine tools industries 76, maintenance is ranked second of all the cost factors. Hence, utilizing an effective maintenance policy is a very important operational decision.Although maintenance policies have been extensively studied in the literature, most of the studies focus on single machines. The literature on maintenance policies in large manufacturing systems, especially in RMSs, is very limited. On the system level, maintenance policies should be developed according to Principle 6: Perform effective maintenance that jointly maximizes the machine reliability and the system throughput. System-level maintenance decision-making is complex because of the following reasons 77: 1) There are different types of maintenance policies (e.g., inspection, preventive maintenance, corrective maintenance), and all have to be addressed simultaneously at the system level; 2) multiple sources of information should be integrated, from machine level (e.g., health states of machines) to system level (e.g., buffer contents, throughput requirement, and the availability of maintenancepersonnel). The maintenance decisionmaking in large manufacturing systems addressed in the literature includes maintenance resource allocation 78,maintenance opportunity identification 7981, and maintenance scheduling 82.Note that in RMSs, although all the parallel machines in the same stage perform the same operations, the health condition of each machine may be different. In addition, the maintenance policies in RMS should be considered jointly with the reconfiguration process. These factors cause the maintenance decision-making problem to be even more difficult.Due to the complexity of the problem, most maintenance policies in RMSs are developed by using simulation-based approaches. For example, Zhou et al. 82 developed an integrated reconfiguration and age-based maintenance (IRABM) policy and applied it to an RMS. Xia et al.83 considered the RMS maintenance opportunities, and proposed a reconfigurable maintenance time window (RMTW) method to make real-time schedules for system-level opportunistic maintenance, which can respond rapidly to various system-level reconfigurations. Considering the operation process rebuilding of manufacturing/operation systems, Xia et al. 84 proposed a dynamic interactive bi-level (i.e., machine and system) maintenance methodology to satisfy rapid market changes. These proposed policies are more cost-effective than the conventional preventive maintenance policies. However, compared to other RMS issues, the maintenance decision-making problem is insufficiently explored in RMSs.4 Future research trendsIn the current age of intensified globalization, manufactur-ing enterprises are facing now more competitive pressure than 20 years ago, when RMS was introduced. The challenges of unpredictable market demand, shorter product life cycles, greater product variety, lower produc-tion costs, and higher environmental regulations, have all intensified. To retain “sustainable competitiveness” 85, possessing reconfigurability becomes even more impor-tant: In addition to rapid responsiveness and lower cost, a higher reconfigurability can lead to a better environmental performance 86. Moreover, based on the recent techno-logies in “Industry 4.0”, the development of RMS and modern manufacturing systems is entering a new era. In this section, we propose several potential future research trends, and deliberate onhow the advances in recent technologies can improve the design and operations of RMS.4.1 Concurrent design of product, manufacturing systems, andbusiness strategiesThe product development process of a manufacturing enterprise involves the decision-making on the following three aspects 6: 1) The product characteristics subject to cost and engineering constraints; 2) the manufacturing systems that produce the product, including the system configuration, the selected machines (e.g., functionality, power, accuracy, ranges, and number of axes), and the process parameters (e.g., task precedence, task type, access direction, dimension, accuracy and power needed to perform the task); and 3) the business strategy, or marketing strategy, such as the prediction of sales, the determination of the product price, and the decision on when to introduce a new product into the market. The objectives from these different aspects are usually coupled, but sometimes competing. For example, from manufactur-ing perspective, it is preferable to reduce the product complexity; however, such reduction may result in a product that is less desirable in the marketplace. Therefore, a joint consideration is needed to solve the trade-off, and concurrent design methods should be developed. Most of the current literatures are focused on only one aspect of the design problem, and some studied the joint decision-making on the development of the product and manufac-turing system 46,62,63. However, new research is needed on integrating the business objectives into the engineering decision-making process. Michalek et al. 87 considered the concurrent design problem that balanced the marketing and manufacturing objectives in a production line. The design problem was decomposed into various sub-problems. The optimal design solution should not only determine the optimal manufacturing systems, but must also develop the product evolution strategy as well as the long-term marketing strategy.Note that, the concurrent design problems are challen-ging because of the multiple factors that need to be considered simultaneously. Note that even if just the manufacturing system itself is considered, complex problems, such as joint process planning and line balancing 5,88, or joint process planning and scheduling 69,89,90, must be developed. Such complicated design optimization problems are usually formulated as mathe-matical programming problems where heuristics need tobe developed to find the solution. Renzi et al. 91 reviewed non-exact meta-heuristic and artificial intelligence meth-ods that were applied to solve such RMS design problems. In the future, more complex comprehensive design methods that integrate the business objectives into the engineering should be formulated. Furthermore, a generic design method that synthesizes the different design aspects is still in need 22.We elaborate below on two topics that require comprehensive studies in product-system-business design strategies.1) The role of the cooperate culture in developing product-system-business strategies. Cooperate culture have a profound impact on the system design; it is an emerging area that we call “social-engineering.” The product-system-business design problem is very challenging when these factors are considered. For example, a dilemma may rise between the marketing and the manufacturing departments of a manufacturing enterprise: The former requires products that are more desirable by the market, while the latter prefers to manufacture less complex products, which, in turn, will reduce their price and make them affordable to buyers. To resolve this dilemma, future research should be conducted on the relationship between the enterprise management structure and the firm working culture.Cooperate culture can affect the system design and operation strategies. For example, Koren et al. 92 investigated how the corporate culture (e.g., the reaction time to urgent maintenance request) may affect the selection of the system configuration, and pointed out that a different corporate culture may explain why theU.S. and Japan prefer different system configurations.2) The potential advancement of the equipment and operations. RMSs can achieve high system sustainability due to its capability of producing multiple generations of products. However, in order to improve the system efficiency during its entire lifecycle, one should consider not only the current state-of-the-art technology but also how technology may evolve in the future. For example, more reliable machines, innovative control technology, new sensors may impact the optimal system design (e.g., system configuration). For example, as pointed out in Ref. 29, with higher machine availability, an SLP configuration has a higher throughput than the RMS configuration.4.2 Improving the effectiveness and efficiency of real-timeoperational decision-making59Compared to the production planning problem, the real-time operational decision-making for RMSs is limited in literature. The main challenge is the complexity of the system, and the requirement of an efficiency of the developed strategy/algorithm that can be used in real time.As mentioned above, maintenance decision-making is very complicated; it is even more complicated when the maintenance and production scheduling problems are jointly considered. For example, based on the product requirement and the health condition of machines, how to optimally perform maintenance, and at the same time, choose the production routes by using the machines that are not under maintenance? Such problems are very complicated, especially when the decision is needed in real-time. Most of traditional analytical and decision-support tools are unable to deal with such a level of complexity, or they can only deal with such complexity very inefficiently.The effectiveness and efficiency of real-time decision-making can be improved by applying intelligent manu-facturing techniques, such as multi-agent systems 93, cloud manufacturing 94, digital manufacturing 95 and cyber physical systems 96. For example, He et al. 93 developed a novel mechanism that enables manufacturing resources to be self-organized cost-efficiently within structural constraints of a make-to-order manufacturing system for fulfilling customer orders.Next, we discuss on how the big-data techniques and cyber physical manufacturing system techniques can improve the design of RMSs. Based on the advanced monitoring and analytics capabilities, more effective and intelligent maintenance and production-scheduling deci-sions can be made in real-time.1) The rapid development of sensor technologies and data analytics methods has significantly improved the prognostics and diagnostics capabilities of manufacturing systems, and thus driven the systems continuous improve-ment. In todays manufacturing systems, more data are collected from machines and processes, which are analysed and provide better knowledge of the system status, including both on-line status and offline characterization. Moreover, the computing capabilities that are aided by the cloud-based approaches are advancing rapidly. Such capabilities enable the development and deployment of more efficient prognostics and diagnostics techniques 94, including online monitoring 97,98, remote monitoring 99, anomaly detection 100 and remaining useful life prediction 101, in manufacturing systems. Future research is needed on developing of flexible or reconfigur-ablecondition monitoring systems 102, which can integrate several decision-support tools such as data collection, feature selection, and sensor allocation.2) The recent development of the cyber physical manufacturing systems has the potential to solve these challenges. Monostori et al. 96 reviewed the key techniques in cyber physical systems (CPSs), and illustrated how it could be implemented in the manufactur-ing environment with several case studies. A CPS has two components, physical and cyber, that are interconnected. The cyber system deploys a “digital twin” of the real system, which can be considered as a mirrored image of the real machines and operations 103. While the real system operates in the physical world, the digital twin operates in the cloud platform, simulates the health condition of each individual machine in the system, and continuously records and tracks machine conditions, energy consump-tion, product quality, and all kinds of information. Data-driven models and algorithms can be developed 104, which can be further integrated into the simulation model, together with physical knowledge. With ubiquitous connectivity offered by cloud computing technology, the cyber system will be able to provide better accessibility of machine condition for factory managers. More impor-tantly, simulation on the digital twin will enable optimal decision-making, such as evaluating alternative mainte-nance and production scheduling policies. Once optimal or near-optimal solutions are found in the cyber system, they will be executed in the physical system to improve its operation.4.3 From mass customization to mass individualizationToday, customers requirements become more versatile and personalized. Contributed to the development of technologies in additive manufacturing and 3D printing 105, the personalized products can be manufactured cost-effectively, which transfers the manufacturing paradigm from mass customization to mass individualization. In this new paradigm, open-architecture products will be devel-oped 106. One key challenge for mass individualization is the huge number of possible modules that need to be assembled into a complex product. Therefore, the manufacturing system (an assembly system in this case) should be able to produce a large number of different models, and should be a reconfigurable assembly system (RAS).The characteristics and principles of RMS that are introduced in Sections 2 and 3 can be implemented to improve the design and operations of RAS. However, thedesign and operations of such RAS is more complicated than that of a traditional RMS for machining. For example, the RAS should be scalable to supply more variants of demand, and be convertible to accommodate various variations and new products. The design topics of an RAS also include modelling systems that couple complex interaction among different machines, line balancing, and production scheduling, etc. 107. In addition, new metrics are needed to quantitatively measure the complexity of the system configuration and the products.New system layout for contemporary RAS should be developed in order to improve the system efficiency and reduce the operational cost. For example, Fig. 6 shows a hexagon layout of conceptual RAS for the final assembly of personalized auto interiors 106,108. Each small square represents a station where a particular component is assembled. When the process proceeds via different routes, different combinations of components can be installed, making different product variants. Some stations in the systems are shared by multiple product variants. For example, for the system in Fig. 6, station 1E is shared by three product variants (I, II, and IV), and there are 13 stations (i.e., 1D, 1F, 2C, 3A, 3D, 3F, 4C, 4D, 4E, 4F, 5C, 6C, and 6F) that are shared by two product variants. To meet the demand requirement, popular components will require more than one assembly station. Such configura-tion enables freely variable assembly routes to produce the personalized product quickly and at low cost.To make mass individualization a reality and to confront with the complexity brought by the huge variety offered by this paradigm, a RAS should combine the advantages of both robots and humans. The recent development of collaborative robot systems 109111 may offer a way to improve the efficiency and adaptiveness of RASs.The robot has a high precision and repeatability, while the human is more adaptive, and can deal better with complex tasks and unexpected situation. The cycle time of the robot is fixed, but the time needed for a person to complete the task is not fixed, especially when complex tasks are involved. A serial assembly line is not a cost-effective solution for utilizing robot-human assembly tasks in large volumes. Therefore, for utilizing effectively collaborative man-robot tasks in high-volume assembly, an RAS with either the configuration depicted in Fig. 4(b) or the configuration in Fig. 6 should be designed and deployed.Fig. 6A conceptual layout of a reconfigurable assembly syste5 ConclusionsRMS is a new type of manufacturing system that focuses on enhancing the system responsiveness to fluctuating markets and enabling rapid and cost-effective competition in environment of volatile markets. In this paper, we have introduced the concept and architecture of RMS, and explained how it differs from other manufacturing systems such as DML and FMS. We defined the RMS characteristics and its principles, and brought up examples to illustrate them. Based on the principles, the RMS-related research in the literature is reviewed, which provides guidance for the design and operations of RMSs. We have also discussed the role of intelligent manufacturing technologies in enhancing RMS performance, and how recent development of advanced diagnostics and cyber physical manufacturing systems can facilitate the design and operations of RMS. Future research should be conducted on the concurrent design of the product-system-business strategies utilizing the RMS concept and principles, as well as for more effective methodologies for real-time RMS operations, for both machining and assembly systems.We believe that RMS has already played a vital role in the evolution of manufacturing systems, and, integrated with other novel techniques, will continue to revolutionize the future development of modern manufacturing systems.译文可重构制造系统：原理、设计和未来趋势摘要：可重构制造系统（rmss）具有专用系列和灵活的制造系统的优点，于 1990 年代中期推出，以应对全球化带来的挑战。rms 的主要目标是提高制造系统对产品需求意外变化的响应能力。rmss 具有成本效益，因为它提高了生产效率，并延长了制造系统的寿命。由于在 rms 上可以生产一个产品的许多流，在 rms 中保持产品的精度是一种方法。关键词：可重构的制造系统，响应，智能制造1 前言在过去的 100 年里，随着经济和社会环境的变化，制造业世界发生了巨大变化。在不同时期不同需求的驱动下，采用了制造技术和新模式来应对经济挑战， 并满足社会需求。面对成本效益的要求，亨利福特在 1913 年发明了移动装配线， 开始了大规模生产模式。20 世纪 70 年代，日本制造业开始制定精益生产原则， 自那以来，产品质量一直保持稳定。值得注意的是 1996 年，Koren 博士提出的建立“可重构制造系统工程研究中心”的建议得到了美国国家科学基金会的批准。该公司是在密歇根大学建立的， 获得了来自 nsf 为期 11 年的 3300 万美元的拨款。工业和密歇根州提供了 1400 万美元的配套资金。该中心创建了 rms 科学基地，并发明了在美国汽车和航空航天工业中应用的 rms 技术，从而提高了工业竞争力。在本文中，我们提出了指导 rms 设计和运行的原则。根据这些原则，我们回顾并评价了文献中提出的最新 rms 设计问题。同时讨论了 rms 未来可能的发展。2.1 rms 的特点和原则在 20 世纪的最后几十年，制造业利用了两种常见的制造系统:专用生产线(DMLs)和 FMSs。DMLs 的设计是为了能够以非常低的成本和非常高的吞吐量来实现特定产品的大规模生产。FMSs 的设计目的是使任何产品的生产(限制在一个几何包内)，但是与 DMLs 相比，它们的吞吐量非常低。DML 是用固定自动化设计的，以非常高的速度生产公司的核心产品。在生产过程中，许多工具可以在生产线上的每台机器上进行模拟操作，从而导致系统吞吐量极高。DML 结构是固定的，不能改变，既不能增加吞吐量，也不能产生不同的产品。如果市场需要更高的吞吐量，DML 就不能满足全部需求，公司就失去了销售机会，从而可能失去市场份额。如果市场需要不同的产品，DML 是无用的，必须报废。相比之下，FMSs 具有一般的灵活性，可以生产多种产品，但其生产成本远高于生产 DMLs。FMS 由通用数控机床和其他可编程自动化设备组成。与许多工具同时操作的 DML 机器相比，每个 CNC 机器在操作过程中使用一个工具。因此，FMS 的吞吐量远低于 DML(相同的投资成本)。FMS 的主要缺点是高投资成本(在机器和工具上)和相对较低的吞吐量。由于对数控设备的投资较多，以及在系统中大量刀具的使用，使得 FMS 的大量生产成为一个重要的经济问题。RMS 的主要优点是它的功能和容量可以快速和(2)成本有效地改变。这是一个 DML 和 FMS 都不具备的特性。RMS 的吞吐量高于 FMS 的吞吐量，但它低于 DML(用于相同的投资成本)。RMS 的设计是围绕着生产一组零件(例如，汽缸头，由可重构的加工系统制造)或产品(例如，组装在可重组装配系统中的发动机)，因此它的灵活性比 DML 高得多。在参考文献9中，对这三种类型的制造系统进行了全面的比较，并在参考文献10中提出了它们与可调制造系统的比较。2.2 RMS 的核心特点和原理RMS 定义如下:一个 RMS 是设计在为了快速调整其生产能力和功能，以适应市场或监管要求的突然变化，在结构、硬件和软件组件上迅速地改变其生产能力和功能。RMS 具有表 1 总结的六个核心特征。六个核心 RMS 特性减少了重构的时间和成本，从而增强了系统响应性。它们在美国的汽车、航空、食品和饮料行业广泛实施，基于这些 RMS 核心特性，制定了以下 RMS 原则。RMS 原则:1) 设计制造系统能力，适应未来市场需求(可扩展性);2) 设计适应客户新产品(可兑换)的制造系统;3) 设计最优嵌入式产品质量检测到制造系统(诊断能力);4) 围绕产品族(定制)设计制造系统;5) 通过重新配置操作和将任务重新分配给机器来最大化系统生产力;6) 进行有效的维护，使机器的可靠性和系统吞吐量最大化。前四个是系统设计原则，利用“模块化”和“可积性”的特点来实现成本效益的设计。例如，在系统级别上，每台机器都是一个模块，并且集成是用物料处理系统来完成的(例如，gantry 或输送机)。原则 5 和 6 是系统操作原则，提高系统的生产率和可靠性。基于原则 5,ERC-RMS 创建了系统平衡软件，该软件在通用汽车和克莱斯勒的 22 家工厂实现，并产生了大量的节省。例如，美国副总裁布莱恩哈洛(Brian Harlow)表示:“通过使用 ERC-RMS 线平衡软件，克莱斯勒成功地将 10%的运营成本节省在了位于底特律的 MackAvenue 发动机工厂的发动机装配线上，这是极其重要的。”针对 RMS 关键特性11提出了数学定义0，特别是对于可扩展性12、可转换性13和综合多属性可重构性指数14。这些特点和原则适用于不同类型的可重构制造系统的设计，包括机械系统、固定系统、装配系统和材料处理系统15,16， 使用各种模型17-20和方法21,22。2.3 重构技术的例子为了说明 RMS 的核心特性，下面给出了三个重构技术的例子机器、检查和系统。2.3.1 可重构机床可重构机床(RMTs)是为特定的操作需求而设计的，可以快速地从一个配置转换到另一个配置。RMT 的设计通常集中在一个特定的部分家庭，并且应该可以快速的调整其结构和/或操作的变化，以制造部分家庭的各个部分。1999 年，世界上第一个关于 RMT 的专利发布23。图 2(a)显示了由 ERC-RMS 构建的 archtype RMT，并在 2002 年在芝加哥的国际制造展上展出。它的设计是在倾斜的表面上钻孔和研磨，使工具垂直于表面。RMT 是可重构这五个角位置的主轴从-15在步骤 15、45和重新配置从一个角到另一个地方只需要不到 2 分钟。这是用来磨机和钻机引擎块 30、45的角度。2.3.2 可重构检验机可重构检验机(RIM)代表了一种过程检查机器，它可以被重新配置，以适应被检查的部件的几何形状。2003 年，世界上第一个关于 RIM 的专利发布24。图 2(b)显示了一个由精确的传送带组成的轮缘的例子，它沿一个精确的运动轴移动，在一系列光电设备中，例如数字或直线扫描照相机和激光传感器。根据正在测量的部分，可以重新配置边缘传感器的位置和数量，以适应被检查部件的几何形状。图 2(b)中所示的边缘被配置为测量气缸盖。在部件的一边有两个激光传感器;另一方面，还有另外三个激光传感器和一个精确的计算机视觉系统。2006 年，通用汽车公司在密歇根州弗林特的发动机工厂安装了一个由 ERC-RMS 开发的轮辋。这个边缘利用机器视觉，有效地检测在发动机缸体上的小表面气孔( 1 毫米)，以检查每一部分。利用轮辋极大地提高了产品的质量，大大减少了因噪音引擎而导致的召回数量。2.3.3 可重构制造系统一个典型的 RMS 集成了 CNC 机器和几个用于制造一个产品系列的 RMTs，以及在其制造过程中检查产品的产品质量检查机器(即:不仅是在生产线的末端。RMS 的结构很容易改变，可以增加更多的生产资源。通过增加生产资源来重新配置的选择应该在各个级别进行计划，硬件，软件和控制，使增加的机器，在线检测站，龙门，等等。世界第一专利的 RMS 在 1998 年填补25。在 1998-2000 年设计和建造的福特温莎发动机工厂中，大约有 120 台 CNC机器，它们被安排在一个可重构的系统体系结构中，由 20 个阶段组成，每台 6 台机器(如图 3 所示)26。福特汽车公司(Ford Motor Co.)称该系统为“灵活、可重构的制造系统”。因为数控机床可以生产多种产品。图 3 福特 Winsor 发动机工厂与 CNC 机器26注意，在系统级，每个 CNC 机器都是一个模块，当系统需要一个新的部件时， 它的功能可以被转换。在系统的每个阶段，都有多个并行的 CNC 机器，通过使用gan 尝试加载和卸载 CNCs 来集成到系统中。此外，系统中的所有阶段都集成到一个大型系统中，由高架桥在各个阶段之间传输部件。该系统具有可诊断的特点， 包括位于关键机加工站旁的在线检测站。该系统是可伸缩的，即可以很容易地将机器添加到系统中以增加系统容量。实际上，自 2000 年以来，福特工厂经历了三次重新配置，其中增加了产能。请注意，如果在某些阶段的 CNCs 被 RMTs 替换， 可以处理某个部分的家庭，那么将实现定制特性。RMS 原理广泛应用于可重构机器27、加工系统15和装配系统16的设计中。接下来，我们回顾了系统级设计和操作中的相关研究问题。不同于其他一般性评论11,15,16,22，本文根据我们在第 2.2 节中制定的原则，对 RMSs 的设计和操作进行了回顾。3 .可重构制造系统的设计与操作制造系统的设计者必须决定:1)系统配置在系统中设置和连接机器的方式;2)设备机器的数量和类 型、材料处理系统、在线检测设备;3)流程规划将操作分配给系统中的每台机器。3.1 选择系统配置。生产系统的性能(例如吞吐量)和特性(例如，可伸缩性)可以明显地依赖于系统配置28。我们详细介绍了三种类型的制造系统配置:串行生产线、并行系统和可重构制造系统。系统类型应在系统设计阶段仔细确定，因为一旦确定，以后就不能改变。根据制造企业的业务目标，在选择系统配置时应该考虑和优先考虑四个主要性能指标:1) 投资成本;2) 机器故障恢复能力;3) 对市场的响应速度(即:，增加产量以配合未来更高的需求);4) 质量生产环境中产品质量的一致性水平。传统的制造系统配置主要有两种类型:由专用的或柔性的机器组成的纯串行线，以及由 CNC 机器组成的纯并行系统。串行加工线的缺点是其吞吐量对机器故障的灵敏度高，对变化的市场缺乏响应性。并行配置对机器故障不敏感，并且可以通过在并行中增加更多的机器来轻松地增加它们的吞吐量。然而,平行配置非常 expen-sive,因为:1)每台机器必须能够执行所有的生产任务,大大增加了每台机器的能力,因此其成本,和 2)系统中的工具总成本是昂贵的(每台机器的工具盒必须包括生产所需的所有工具部分)。由于这些缺点，在实践中很少发现并行系统。大型加工系统,有两种类型的配置中常用的工业:1)一个由几种配置串行线安排在并行(SLP)和 2)RMS 配置,包括几个阶段,每个阶段包含多个平行相同的机器(通常加工中心或 reconfigur-able 机)。SLP 和 RMS 配置的原理图如图 4 所示。图 4 中的两个系统都有相同数量的机器。SLP 与 RMS 的主要区别。126 年前。动力机械。Eng。2018,13(2):121 - 136配置是 RMS 具有跨界连接，可以在并行模式下在每个阶段操作这三种机器。在实践中，在每个阶段中操作的 gantry 可以支持这些连接。在那个阶段，龙门装载和卸载部件到或从每台机器。这些机架的成本使得 RMS 比 SLP 配置更加昂贵。但是，RMS 的两个主要优点是:1)资源(例如，机器)可以非常快速和成本有效地增加，从而使对变化的市场的响应速度更快;2)如果 gantry 可用性高于机器可用性，则 RMS 中机器故障的吞吐量依赖性小于串行线的吞吐量。Freiheit 等29开发了一个模型，比较了 SLPs 和 RMSs 的吞吐量。它证明了 RMS 配置对大型系统具有更高的吞吐量。，每个阶段有更多阶段或更多机器的系统。Gu30将分析扩展到带有缓冲区的系统，并显示在系统中添加小缓冲区时，RMS 是有利的。除了吞吐量，Koren 等31还从其他角度比较了 SLP 和 RMS 配置的性能，包括成本、响应性和产品质量的一致性。此外，在 RMS 配置中，每个阶段不一定拥有相同数量的机器。实际上，在相同数量的机器上，RMS 配置比 SLP 配置要多。为了选择最优的 RMS 配置，已经考虑了各种复杂的优化问题。例如，Youssef 和 ElMaraghy32提出了一个多方面、多部分RMS 配置的建模和优化过程，并考虑了一些未来的重新配置计划。Dou 等33 建立了一个优化程序，它决定了系统的配置，机器的类型，以及分配给每个阶段的操作。Goyal 等34基于 RMTs 的可重构性和操作能力，开发了选择最优 RMS 配置的算法。请注意，对于可重新配置的组装系统，要阻止。在可重构加工系统中，挖掘最优配置要复杂得多。Webbink 和胡锦涛35研究了给定装配站的数量，如何生成装配系统配置。Benka-moun 等36回顾了在装配系统设计中处理品种和产品变化的主要策略。3.2 利用 RMS 原理设计和操作系统。我们将详细说明如何利用六个 RMS 原则来优化系统设计及其操作。3.2.1 利用原则 1 进行容量规划。生产能力指的是制造系统每年能生产的产品的最大数量。在未来不可预测的市场变化环境中，设计新系统的能力是一项重大挑战。如果未来市场需求低于系统容量，机器就会闲置，这将导致巨大的资本损失。如果未来需求高于产能，公司将失去销售机会，从而可能失去市场份额。建造一个拥有大型制造系统的工厂可能需要 2 - 3 年的时间，然后在 12 到25 年内投入运营。新制造系统的设计能力对工厂未来的盈利能力至关重要，但企业业务部门对未来几年的预测需求(例如，最多 8 年)提供数据预测。如何利用这种预测来设计一个最优的制造系统?RMS 为这一挑战提供了经济上的响应。RMS 是根据原则 1 建立的:设计制造系统的能力，以适应未来市场的需求。为了确定系统设计阶段的最佳容量，以及未来可能的容量扩展策略，已经开发了各种模型。例如，Narong-wanich 等37研究了最优容量。一个公司的投资组合，它利用了两种类型的系统一个专用的制造系统(DMS)和一个 RMS。作为福特副总裁，Krygier 先生在 Ref.27中报道， 福特利用他们的模型为新的温莎引擎工厂购买了 RMS。Deif 和 ElMaraghy38考虑了一个 RMS 的能力规划问题，其中的成本函数包含了基于物理能力的成本以及与重构过程相关的成本。Gyulai 等39研究了装配系统的能力规划问题，以决定某一产品是否应该在专用的或可重构的线上组装，还是应该外包。瑞恩40