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手动
穿串机
设计
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手动穿串机设计,手动,穿串机,设计
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摘要本产品适用于新型食品加工行业。由于传统手工穿串不卫生、人员不稳定、人工在穿插不注意时很容易穿到手上发生危险、产量不高，所以研制一种手动穿插机构代替传统手工，提高工作效率降低劳动强度。本文介绍传动系统和进给机构设计方案的选定，并对所用的齿轮传动和链传动进行了详细计算，对弹簧、齿轮、链轮和轴进行强度、刚度的校核计算。本产品采用同步链达到供料和穿插动作同步，实现穿插动作的完成。本机构是在食品装料机械的基础上设计的。此机构具有结构简单、体积小、成本低等优点。关键词 穿插机械；链传动；食品加工Abstract This product is suitable the new food processing profession. Because the tradition puts on the sting not health,the personnel is not stably,the man-power when interludes dose not pay attention is very easy to be danger,the out put is not to be higher, therefore develops one kind of manual interludes organization to replace the traditional manual enhancement working efficiency to reduce the labor intensity.This article introduced that the transmission system and the feed system design proposals designation,and to the gear drive which and the chain drive used has carried on the detailed computation,to the springing, the gear,the chain wheel and the axis carried on the intensity,the rigidity examination computation.This produce uses the synchronized chain to achieve for the material and the interludes movement synchronization,realizes interludes movement completion.This organization is in food feed in machinerys foundation to design,this organization has the structure to be simple,the volume is small,cost low and otherwise merit.Keywords Insertes machinery Chain drive Food processingII目 录1 绪论12 方案的设计及其论证22.1 穿串工作的现状22.2 手工穿串存在的问题22.3 方案设计22.4 优点和缺点22.4.1 优点 22.4.2 缺点 23 传动机构设计 33.1 传动系统的选择33.2 齿轮传动的设计33.2.1 选择齿轮材料 43.2.2 按齿面接触疲劳强度设计计算 43.3 链轮、链条的设计及润滑 73.3.1 链条的设计计算 73.3.2 链轮的设计计算 83.3.3 链传动的润滑103.4 轴承的选定103.5 轴承的润滑113.5.1 轴承润滑的作用113.5.2 脂润滑和油润滑的比较113.5.3 脂润滑123.5.4 润滑脂的选择123.5.5 油润滑123.5.6 润滑剂的补充与更换133.5.7 轴承的密封134 振动系统的设计 144.1 振动系统的发展与现状144.2 弹簧的设计174.2.1 计算弹簧的直径174.2.2 弹簧的强度计算184.2.3 弹簧的刚度计算194.2.4 弹簧的稳定性计算194.3 凸轮机构的设计194.3.1 圆柱凸轮机构在自动机械中的作用194.3.2 凸轮机构的组成204.3.3 凸轮机构的分类204.3.4 凸轮机构的特点214.3.5 凸轮机构轮廓曲面的通用计算224.3.6 圆柱凸轮机构轮廓曲面参数的求解224.3.7 圆柱凸轮分度机构的设计参数选择245 轴的设计 285.1 轴的设计步骤 285.2 基于疲劳强度的安全系数约束 295.3 基于静强度的安全系数约束305.4 初步确定轴的最小直径315.5 轴的结构设计 315.6 按弯扭合成应力校核轴的强度 32结论 35致谢 36参考文献 37附录 38附录 138531 绪论1.1 序言毕业设计是培养我们理工科学生的一个实践性教学环节，也是最后一个教学环节，它是在我们学完了全部基础课、技术基础课及专业课后，并在一些课程设计基础上，到工厂进行参观实习，搜集原始资料之后，进行的一次大规模基本知识和基本技能的全面的、系统的设计。设计的主要目的：培养我们综合应用所学基本知识和基本技能去分析和解决专业范围内的一般工程技术问题的能力，培养我们建立正确的设计思想、掌握工程设计的一般程序、规范和方法，培养我们收集和查阅资料和运用资料的能力。通过毕业设计，进一步巩固、扩大和深化我们所学的基本理论、基本知识和基本技能，提高我们设计、计算、制图、编写技术文件，正确使用技术资料、标准手册等工具书的独立工作能力。通过毕业设计，培养我们严肃认真、一丝不苟和实事求是的工作作风，树立正确的生产观、经济观和全局观，从而实现我们向工程技术人员的过度，同时学会调查、研究、收集技术资料的方法。在制造业信息化环境中，工艺设计是生产技术准备工作的第一步，工艺规程是进行工装设计制造和决定零件加工方法与加工路线的主要依据，它对组织生产、保证产品质量、提高劳动生产率、降低成本、缩短生产周期及改善劳动条件等都有直接的影响，是生产中的关键工作。工艺知识是制造企业中重要的知识资源之一，是使产品设计变为成品的整个制造过程中的基础资源，它对保证产品质量以及提高企业经济技术效益具有十分重要的作用。随着国民经济的发展，工程机械的应用越来越多，因为工程机械能够代替工人从事重体力劳动。使用工程机械的优点有很多，如工程机械的适应能力很强，一般不受气候影响，工程机械可以不需要休息，工作效率高，工程机械动力强劲等。但是工程机械一般只注重实用性，而舒适性大都会被忽略。而由于社会的进步，国家对工人的工作条件日益关注（工人在工作条件恶劣的情况下，一般工作效率都比的低，）。所以开发一些能改善工人工作条件的产品上很有必要的。而本课题也正是从这一方面考虑的。当前，社会经济正经历着从工业经济向知识经济转变的过程，知识正在成为生产力要素中最活跃、最重要的部分。相信通过这次设计，使我的知识积累达到了一个新的层面！2 方案的设计和论证2.1 穿串的现状到目前为止都是用手工穿制的，速度慢工作效率低，直接影响产量。我们迫切需要解决这一个难题。随着一些厂家研制出一系列的自动穿串机械。在很大程度上解决一些问题。但是，自动穿串机都存在着体积大，成本高，结构复杂的特点。仅仅适用于一些规模较大的食品厂家。所以在很大程度上在市场上还是采用手工穿制。2.2 手工穿串存在的问题人工穿制主要的存在一系列的问题，例如：1、不卫生。2、人员不稳定，影响产量。3、人工在穿插不注意时很容易穿到手上发生危险。4、产量不高。2.3 方案设计：整体设计：本产品包括：动力输入设备、输送设备、震动设计、穿插设备、传动设备等。动力输入：本产品采用人工手摇输入动力 。按一个正常的工人体能可输入196N 的力。传动设备：本产品通过人工手摇动一个摇柄，带动Z1 齿轮。按传动比为68/22 大小，带动Z2齿轮工作。输送设备：本产品采用齿轮和链轮同轴实现同步，同过输送链来实现输送。在工作过程中一顶要保证输送竹签和面团同步，一一对应。震动设计：本产品的料从漏斗下来时，为了保证在下料过程中不发生堵塞情况发生，采用凸轮震动来保证。穿插设备：在本产品中关键在实现穿插动作。采用斜插入式，在设备的中部用一光轴当着轨道。下端和Z2 齿轮用一弯杆相连接。保证穿插机构和传动设备同步。此设备采用两边对插，相差半个周期。2.4 优点和缺点2.4.1 优点：1、结构简单，成本低，体积小；2、操作方便，工作安全；3、噪音小4、操作部位适应人体生理条件，维修方便；2.4.2 缺点：有轻微的冲击3 传动机构设计3.1 传动系统的选择根据上一章的方案选择，本系统采用齿轮传动和链传动，传动系统简图(简单的原理)如图3-1 所示：图3-1传动系统简图本产品通过人工手摇动一个摇柄，带动Z1 齿轮。按传动比为68/22 大小，带动Z2 齿轮工作。在和同轴上是三对链轮，分别有来带动三条传输链。每个链轮的大小和齿数完全相同。在Z1 齿轮转动时，带动Z2齿轮的转动同时带动O1 轴上的三个链轮转动，实现同步运动。达到穿插的同步。在Z2 齿轮上有一销钉带动弯杆1，作扇形运动。拉动推进机构1 作来回往复运动，完成穿插动作。在O1 轴的另一端也用同样的Z2齿轮，带动弯杆2 完成推进机构2 的穿插动作。弯杆1 和弯杆2 和Z2 齿轮和齿Z2齿轮在连接时要相差半个周期。实现相互穿插。在推进机构1 完成穿插动作时，推进机构2 已经开始穿插。当推进机构2 完成时，推进机构1 也已经准备穿插。3.2 齿轮传动的设计齿轮传动的适用范围很广，传递功率高。其主要优点工作可靠，使用寿命长；瞬间传动比为常数；传动效率高；结构紧凑；功率和速度适用范围广泛等。齿轮传动应满足：1 传动平稳：要求瞬时传动比不变，尽量减小冲击；2 承载能力高：要求在尺寸很小，重量轻的前提下，齿轮的强度高，耐磨性好，在预定的使用期间内不出现断齿等失效情况。3.2.1 选择齿轮材料查阅机械设计工程学1（中国矿业大学出版社）（以下称为机械设计1）表8-17：齿轮选用45号钢调质，表面淬火。HBS=245-2753.2.2 按齿面接触疲劳强度设计计算采用硬齿面，非对称分布。查机械设计1的表8-23 得齿宽系数 =0.4 齿轮齿数在推荐值20 到40 中选取 =22齿轮模数m可由机械传动装置设计手册(上册，卜炎主编)查得。 m=3齿轮分度圆直径固圆周速度 参考机械设计1表8-14和表8-15选取 齿轮的齿距 公差组10 级 p=9.42齿轮的齿数 圆整取 齿数比 载荷系数K 由机械设计1中式(8-45) 得使用系数查机械设计1的表（8-20）动载荷系数查机械设计1的图（8-57）得初值 齿向载荷分布系数查机械设计1的图（8-60）得 齿间载荷分布系数由机械设计1的式(8-55)及得=1.69查机械设计1 表8-21并插值得 则载荷系数K的初值 =1.36 弹性系数查机械设计1表（8-22）节点影响系数查机械设计1图（8-64）（） 重合度系数查机械设计1图（8-65）（） 许用接触应力，由机械设计1式(8-69)得接触疲劳极限应力，查机械设计1图（8-69）得应力循环次数由机械设计1式(8-70)得按预期寿命10年。每年工作300天。每天工作8小时。=则查机械设计1图（8-70）得接触强度的寿命系数， (不允许有点蚀) 硬化系数，查机械设计1图（8-71）及说明得 接触强度安全系数，查机械设计1表8-27，按一般可靠度查=1.0到1.1取=1.05故的设计初值为所以为66mm可用。齿厚b = 齿宽=26mm 齿轮宽 =33mm由于采用正常齿轮，所以齿顶高系数取，顶隙系数取，分度圆的压力角度数为标准值 确定齿轮的其他参数如下：分度圆直径：齿顶高： 齿根高： 齿全高： 齿顶圆直径： 齿根圆直径： 基圆直径： 齿距： 齿厚： 齿槽宽： 基圆齿距： 法向齿距： 顶隙： 齿轮采用锻造齿轮，结构采用普通结构（见中国机械设计大典（以后简称为设计大典）表32.1-62。3.3 链轮、链条的设计及润滑3.3.1 链条的设计计算由于此传动要求速度较低，线速度应该小于0.6m/s，属于低速重载形式的连传动，链条的静强度占有主要地位。如果低速链也按疲劳考虑，用额定功率曲线选择和计算，结果常不经济。所以，此处采用静强度计算的方法确定链的规格。链条的静强度计算式为： 式（3.1)式中 n-表示静强度安全系数Q-表示链条抗拉载荷-表示工况系数F-表示有效拉力-表示离心力引起的拉力-表示悬垂拉力-许用安全系数，一般为48，此处选择为8此处要确定链条的型号，也就是求链条的抗拉载荷。由于动力源是手动，而且根据面团和竹签的重量，可以知道此提升机构属于中型升降机，查阅 中国机械设计大典表36.2-5可以得到： 分析受力示意图图如图3-2 所示图3-2 受力示意图由于此处采用的不是闭合链，所以 也可以忽略不记所以有： 查阅中国机械设计大典表36.2-3 可得08B号链在单排时的抗拉载荷是86.7KN，所以决定选择08B号链作为此次设计的传动链。滚子链的具体参数如表3-1 所示。下面来确定链的节数，开始穿插时，所需的链条最长，由于开始到完成之间的距离取800mm，两个链轮的直径是170mm，所以链条的计算长度l 要满足下面的条件：表 3-1 滚子链的参数项目尺寸（mm）内链条外宽11.30外链条外宽11.43节距12.70滚子直径8.51内链节内宽7.75考虑到链条与链轮的啮合和其他方面，决定取：l= 2000mm则链条的节数n为： n = l / p 式（3.2）=2000/12.70=157.48 所以，链条的实际长度为； =15712.70=1993.9mm3.3.2 链轮的设计计算由于滚子链与链轮的啮合属于非共轭啮合，其链轮的齿形的设计可以有较大的灵活性。本次设计采用一种三圆弧一直线的齿形，其特点就是齿形与滚子啮合时的接触应力小，啮合性能好。1、确定链轮的齿数 z由于线速度小于 0.6m/s，查阅中国机械设计大典表36.2-4 得下面结果：z=222、确定链轮的其他参数由中国机械设计大典表36.2-13知 式（3.3）式中 d-表示链轮的分度圆直径p-表示配用链条的节距z-表示链轮的齿数从上面的计算可知p 和z 的值，所以有： = 12.70/ sin8.18o=12.70/ 0.1423= 89.25mm为了制造方便，决定对d 进行取整，所以有：d=89mm由中国机械设计大典表36.2-13 知：齿顶圆直径应该在 和 之间取值，而 和 分别为： 式（3.4） 式（3.5）式中 -表示齿顶圆的最大值 -表示齿顶圆的最小值d -表示链轮的分度圆直径p -表示配用链条的节距 -表示配用链条的滚子直径由上面的计算知：d=89mmp=12.7mm=8.51mm所以有： =89+1.2512.70-8.51 =96.365mm =89+（1+1.6/22）12.7-8.51=94.11 mm所以：取为95 mm由中国机械设计大典表36.2-13知：齿跟圆直径为： =95-12.7=82.3mm 式（3.6）取整后有：=82mm齿侧凸圆直径： 式（3.7）式中 内链板高度由中国机械设计大典表36.2-3 可得：=11.81mm所以有： 75.31mm取=75 mm先假设与链轮配合的轴的轴径为40 mm，现在来计算腹板式单排铸造链轮的主要结构尺寸。查阅中国机械设计大典表36.2-22知，轮毂厚度为h为： 式（3.8）= =9.5+40/6+0.95= =17.12mm由中国机械设计大典表36.2-22 同时知 l =4h 式（3.9） 式（3.10）R =0.04p 式（3.11）上述式中 l-表示轮毂宽度-表示轮毂直径R-表示圆角半径由于h、和p都为已知，所以有 l=4h=417.12 =68.48mm=40+217.12 =74.24 mmR=0.04p=0.0412.70 =0.508 mml、和R 分别取为70 mm、74 mm、0.5 mm。由于 =74 mm 200mm)1.82.5注：1、对于转轴或转动心轴，弯曲应力按对称循环变化，故， 0；2、对于固定心轴或载荷随轴一起转动的转动心轴，考虑到载荷波动的实际情况，弯曲应力可作为脉动循环变化考虑，即 ；3、若转矩变化的规律难以确定，一般而言，对单方向转动的转轴，常视扭剪应力按脉动循环变化，即；若轴经常正反转，则应按对称循环处理，即，0。当式(5-4)不能满足时，则说明轴的疲劳强度不足，需采取相应措施予以改进。如改进轴的结构以降低应力集中；采用热处理、表面强化处理等工艺措施提高强度；加大轴的直径；或改用较好材料等。5.3 基于静强度的安全系数约束对于应力循环严重不对称或短时过载严重的轴，在尖峰载荷作用下，可能产生塑性变形，为了防止在疲劳破坏前发生大的塑性变形，还应按尖峰载荷校核轴的静强度安全系数。其约束条件为： 式(5.7) 式(5.8) 式(5.9)式中： -表示静强度计算安全系数，见表5-3；、 -表示受弯矩和转矩作用时的静强度安全系数；-表示静强度最小许用安全系数，见表5-3；、-表示材料抗弯、抗扭屈服极限；、-表示尖峰载荷所产生的最大弯曲、扭剪应力。表5-3静强度的最小许用安全系数0.450.550.550.700.700.90铸造轴 初步确定轴的最小直径先初步估算轴的最小直径。选取轴的材料为45 号钢，调质处理。取=112，于是得输出轴的最小直径显然是安装联轴器处轴的直径。为了使所选的轴直径与联轴器的孔径相适应，故需同时选取联轴器型号。联轴器的计算转矩,考虑到转矩很小，故取，则：=1.3960000 Nmm=1248000 Nmm按照计算转矩应小于联轴器公称转矩的条件，查标准GB5014-85或手册，选用HL4型弹性柱销联轴器，其公称转矩为1250000Nmm。半联轴器的孔径55mm；故取=55mm；半联轴器长度112mm，半联轴器与轴配合的毂孔长度=84mm。5.5 轴的结构设计1、拟定轴上零件的装配方案本题的装配方案已在前面分析比较，现选用如图所示的第一种装配方案。2、根据轴向定位的要求确定轴的各段直径和长度(1) 为了满足半联轴器的轴向定位要求，-轴端右端需制出一轴肩，故取-段的直径62mm；左端用轴端挡圈定位,按轴端直径取挡圈直径D65mm。半联轴器与轴配合的毂孔长度=84mm,为了保证轴端挡圈只压在半联轴器上而不压在轴的端面上，故-段的长度应比略短一些， 现取= 82mm。(2) 初步选择滚动轴承。因轴承同时受有径向力和轴向力的作用。故选用单列圆锥滚子轴承。参照工作要求并根据=62mm，由轴承产品目录中选取0 基本游隙组、标准精度级的单列圆锥滚子轴承30313，其尺寸为dDT=6514036,故=65mm；而=36mm。右端滚动轴承采用轴肩进行定位。由手册上查到30313 型轴承的定位轴肩高度h=6mm，因此，取=77mm。(3) 取安装齿轮处的轴段-的直径=70mm；齿轮的左端与左轴承之间采用套筒定位。已知齿轮轮毂的宽度为80mm，为了使套筒端面可靠地压紧齿轮，此轴段应略短于轮毂宽度，故取=76mm。齿轮的右端采用轴肩定位，轴肩高度h0.07d，取h=6mm,则轴环处的直径=82mm。轴环宽度b1.4h,取=12mm。(4) 轴承端盖的总宽度为20mm（由减速器及轴承端盖的结构设计而定）。根据轴承端盖的装拆及便于对轴承添加润滑脂的要求，取端盖的外端面与半联轴器右端面间的距离l=30mm ，故取=50mm。(5) 取齿轮距箱体内壁之距离a=16mm，圆锥齿轮与圆柱齿轮之间的距离c=20mm。考虑到箱体的铸造误差，在确定滚动轴承位置时，应距箱体内壁一段距离s，取s=8mm。已知滚动轴承宽度 T=36mm，大圆锥齿轮轮毂长L=50mm,则至此，已初步确定了轴的各段直径和长度。3、轴上零件的周向定位齿轮、轴的周向定位均采用平键联接。按由手册查得平键截面bh=2012(GB1095-79)，键槽用键槽铣刀加工，长为63mm(标准键长见 GB1096-79),同时为了保证齿轮轮毂与轴的配合为H7/n6；同样，半联轴器与轴的联接，选用平键为161070，轴的配合为H7/k6。滚动轴承与轴的周向定位是借过渡配合来保证的，此处选轴的直径尺寸公差为m6。4、确定轴上圆角和倒角尺寸：取轴端倒角为。5.6 按弯扭合成应力校核轴的强度进行校核时，通常只校核轴上承受最大计算弯矩的截面（即危险截面C）的强度。则由公式及上表中数值可得前已选定轴的材料为45 号钢，由轴常用材料性能表查得=60MPa。因此，故安全。1、断危险截面截面A,B只受扭矩作用，虽然键槽、轴肩及过渡配合所引起的应力集中均将削弱轴的疲劳强度，但由于轴的最小直径是按扭转强度较为宽裕地确定的，所以截面A,B均无需校核。从应力集中对轴的疲劳强度的影响来看，截面和处过盈配合引起的应力集中最严重；从受载的情况来看，截面C 上最大。截面的应力集中的影响和截面的相近，但截面不受扭矩作用，同时轴径也较大，故不必作强度校核。截面C 上虽然最大，但应力集中不大（过盈配合及键槽引起的应力集中均在两端），而且这里轴的直径最大，故截面C 也不必校核。截面和显然更不必校核。键槽的应力集中系数比过盈配合的小，因而该轴只需校核截面左右两侧即可。图5-1 轴的强度校核示意图2、截面左侧抗弯截面系数 抗扭截面系数 截面左侧的弯矩M为 截面上的扭矩为 =960000 Nmm截面上的弯曲应力 截面上的扭转切应力 轴的材料为45 号钢，调质处理，由常用材料性能表查得=640MPa，275MPa，=155MPa。截面上由于轴肩而形成的理论应力集中系数及按手册查取。因，经插值后可查得，又由手册可得轴的材料的敏性系数为 ，。故有效应力集中系数为结论通过毕业设计,我明白了所学知识的重要性,同时又看到自己以前学习过程中的不足.整个设计的过程就是一个将所学知识进行运用,在运用的过程中再次学习书本知识,这将使我在以后的工作过程中受益匪浅!我所设计的手动穿串机,由于能力所限,还有很多的不足,比如说下料的时候起拱将是个不太好解决的问题,还有卸料的机构也有待于改进.当然我认为整个机器设计的还是比较合理的,这个设计到此已经圆满结束,其中的不足请老师们多多指教,这将是我这次设计中得到的最大收获!本设计利用机械原理设计手动穿插机械，采用齿轮啮合传动，通过链传动实现手动穿插。在整个设计过程中，重点就是整个装置的机械设计，整个机构一定要设计巧妙，如何可以实现穿插机构和竹签，面团同步运动。为了实现这一个目的采用两个相对的推进机构交错穿插。到此，本设计已经全部完成，下图是整个装置的装配图。致谢大学四年的学习以今天的毕业论文画了一个句号。感谢大学四年，各位老师对我的教诲，感谢机电系，感谢大家有缘能在生命中重要的四年，出现在彼此的生活中，感谢上天。很幸运，在我大学的最后一次作业的完成中，能得到刘文君老师的指导与帮助，有了一次宝贵的机会跟刘老师接触。刘老师严谨治学的态度，在我的心里留下深刻的影响。在以后的日子里，我要学习刘文君老师的求实、尊重事实的精神。在以后的科研方面，也要像刘老师那样，尊重数据、尊重事实。在这里，真诚的向刘老师说一句：刘老师，您是亮起在我毕业前的一盏灯，感谢您，祝您一切都好。大学四年，郭华峰老师，高玮老师，陈跃老师和张清老师，对我影响很大！感谢您们对我的帮助！在这里，我还要感谢带过我课的所有老师，班主任和辅导员。在此，同时感谢我的父母，对我的支持，没有他们的支持，我走不到今天。感谢与我共同走过大学的朋友们、同学们，每个在我脆弱、困难的时候，扶过我一把的你，我都记得。感谢所有帮助过我的老师、同学、朋友，感谢你们，在此还要特别感谢同学的真诚无私的帮助，希望你们在以后的日子里，开心、快乐，希望你们过得比我好！参考文献1实用机械设计手册编写组实用机械设计手册；机械工业出版社20072 冯辛安主编 机械制造装备设计 北京北京机械工业出版社 2006.13 许镇宇主编机械零件北京：人民教育出版社，20064 中国机械工程学会 中国机械设计大典编委会编中国机械设计大典南昌江西科学技术出版社 2005.15 张裕中 主编,臧其梅 副主编 食品加工技术装备 中国轻工业出版社2005.36 周开勤主编机械零件手册第四版。20047 严计宽主编机械振动隔离技术上海：上海科学技术文献出版社。20048（美）米什克主编机械设计通用手册河海大学机械学院译。20039 张普礼主编 机械加工设备 北京机械工业出版社 200210 胡继强主编 食品机械与设备 北京：中国轻工业出版社，2002附录附录1：英文原文Process Planning and Concurrent Engineering The product design is the plan for the product and its components and subassemblies.To convert the product design into a physical entity ,a manufacturing plan is needed .The activity of developing such a plan is called process planning .It is the link between product design and manufacturing .Process planning involves determining the sequence of processing and assembly steps that must be accomplished to make the product .In the present chapter ,we examine processing planning and several related topics. At the outset ,we should distinguish between process planning and production planning ,which is covered in the following chapter. Process planning is concerned with the engineering and technological issues of how to make the products and its parts. What types of equipment and tooling are required to fabricate the parts and assemble the product ? Production planning is concerned with the logistics of making the product .After process planning is concerned with ordering the materials and obtaining the resources required to make the product in sufficient quantities to satisfy demand for it.Process Planning Process planning involves determining the most appropriate manufacturing and assembly processes and the sequence in which they should be accomplished to produce a given part or product according to specifications set forth in the product design documentation.The scope and variety of processes that can be planned are generally limited by the available processing equipment and technological capabilities of the company of plant .Parts that cannot be made internally must be purchased from outside vendors. It should be mentioned that the choice of processes is also limited by the details of the product design.This is a point we will return to later. Process planning is usually accomplished by manufacturing engineers .(Other titles include in industrial engineer.) The process planner must be familiar with the particular manufacturing processes available in the factory and be able to interpret engineering drawings .Based on the planners knowledge,skill,and experience ,the processing steps are developed in the most logical sequence to make each part .Following is a list of the many decisions and details usually include within the scope of process planning : .Interpretation of design drawings. The part of product design must be analyzed (materials,dimensions,tolerances ,surface finished,etc.) at the start of the process planning procedure. .Process and sequence. The process planner must select which processes are required and their sequence.A brief description of processing steps must be prepared. .Equipment selection . In general , process planners must develop plans that utilize existing equipment in the plant .Otherwise ,the component must be purchased ,or an investment must be made in new equipment . .Tools ,dies,molds,fixtures,and gages. The process must decide what tooling is required for each processing step.The actual design and fabrication of these tools is usually delegated to a tool design department and tool room ,or an outside vendor specializing in that type of tool is contacted. Methods analysis . Workplace layout ,small tools ,hoists for lifting heavy parts ,even in some cases hand and body motions must be specified for manual operations .The industrial engineering department is usually responsible for this area. .Work standards. Work measurement techniques are used to set time standards for each operation . .Cutting tools and cutting conditions. These must be specified for machining operations ,often with reference to standard handbook recommendations. Process Planning for parts For individual parts,the processing sequence is documented on a form called a route sheet .(Not all companies use the name route sheet ;another name is “operation sheet .”)Just as engineering drawings are used to specify the product design ,route sheets are used to specify the process plan .They are counterparts,one for product design ,the other for manufacturing .A typical route sheet includes the following information: (1) all operations to be performed on the work part ,listed in the order in which they should be performed ; (2) a brief description of each operation indicating the processing to be accomplished,with references to dimensions and tolerances on the part drawing; (3) the specific machines on which the work to be done; and (4) special tooling such as dies molds ,cutting tools,jigs or fixtures ,and gages.Some companies also include setup times ,cycle time standards,and other data.It is called a route sheet because the processing sequence defines the route that the part must follow in the factory . Decisions on process to be used to fabricate a given part are based largely on the starting material for the part .This starting material is selected by the product designer.Once the material has been specified ,the range of the possible processing operation is reduced considerably .The product designers decisions on starting material are based primarily on functional requirements ,although economics and manufacturability a role in the selection. A typical processing sequence to fabricate an individual part consists of : (1) a basic process,(2)secondary processes ,(3) operations to enhance physical properties,and (4)finishing operations. A basic process determines the starting geometry of the workpart.Metal casting ,plastic molding ,and roling of sheet metal are examples of basic processes.The starting geometry must often be refined by secondary processes,operations that transform the starting geometry (or close to final geometry ).The secondary geometry processes that might be used are closely correlated to the basic process that provides the starting geometry.When sand casting is the basic processes,machining operations are generally the second processes .When a rolling mill produces sheet metal,stamping operations such as punching and bending are the secondary processes.When plastic injection molding is the basic process ,secondary operations are often unnecessary,because most of the geometric features that would otherwise require machining can be created by the molding operation.Plastic molding and other operation that require no subsequent secondary processing are called net shape processes.Operations that require some but not much secondary processing (usually machining ) are referred to as near net shape processes.Some impression die forgings are in this category .These parts can often be shaped in the forging operation(basic processes)so that minimal machining (secondary processing )is required . Once the geometry has been established ,the next step for some parts is to improve their mechanical and physical properties .Operations to enhance properties do not alter the geometry of the part;instead,they alter physical properties .Heat treating operations on metal parts are the most common examples .Similar heating treatments are performed on glass to produce tempered glass.For most manufactured parts ,these property-enhancing operations are not required in the processing sequence. Finally finish operations usually provide a coat on the work parts (or assembly )surface. Examples inclued electroplating ,thin film deposition techniques ,and painting.The purpose of the coating is to enhance appearance ,change color ,or protect the surface from corrosion,abrasion ,and so forth .Finishing operations are not required on many parts ;for example, plastic molding rarely require finishing .When finishing is required ,it is usually the final step in the processing sequence .Processing Planning for Assemblies The type of assembly method used for a given product depends on factors such as : (1) the anticipated production quantities ;(2) complexity of the assembled product ,for example ,the number of distinct components ;and (3)assembly processes used ,for example ,mechanical assembly versus welding .For a product that is to be made in relatively small quantities ,assembly is usually performed on manual assembly lines .For simple products of a dozen or so components,to be made in large quantities ,automated assembly systems are appropriate .In any case ,there is a precedence order in which the work must be accomplished .The precedence requirements are sometimes portrayed graphically on a precedence diagram. Process planning for assembly involves development of assembly instructions,but in more detail .For low production quantities,the entire assembly is completed at a single station .For high production on an assembly line ,process planning consists of allocating work elements to the individual stations of the line, a procedure called line balancing.The assembly line routes the work unit to individual stations in the proper order as determined by the line balance solution.As in process planning for individual components ,any tools and fixtures required to accomplish an assembly task must be determined ,designed,and built;and the workstation arrangement must be laid out.Make or Buy Decision An important question that arises in process planning is whether a given part should be produced in the companys own factory or purchased from an outside vendor ,and the answer to this question is known as the make or buy decision .If the company does not possess the technological equipment or expertise in the particular manufacturing processes required to make the part ,then the answer is obvious: The part must be purchased because there is no internal alternative .However ,in many cases ,the part could either be made internally using existing equipment ,or it could be purchased externally from a vendor that process similar manufacturing capability. In our discussion of the make or buy decision ,it should be recognized at the outset that nearly all manufactures buy their raw materials from supplies .A machine shop purchases its starting bar stock from a metals distributor and its sand castings from a foundry .A plastic molding plant buys its molding compound from a chemical company.A stamping press factory purchases sheet metal either fro a distributor or direct from a rolling mill.Very few companies are vertically integrated in their production operations all the way from raw materials ,it seems reasonable to consider purchasing at least some of the parts that would otherwise be produced in its own plant.It is probably appropriate to ask the make or buy question for every component that is used by the company . There are a number of factors that enter into the make or buy decision .We have complied a list of the factors and issues that affect the decision in Table .One would think that cost is the most important factor in determining whether to produce the part or purchase it .If an outside vendor is more proficient than the companys own plant in the manufacturing processes used to make the part ,then the internal production cost is likely to be greater than the purchase price even after the vendor has included a profit .However ,if the decision to purchase results in idle equipment and labor in the companys own plant ,then the apparent advantage of purchasing the part may be lost .Consider the following example come to make or buy decision. The quoted price for a certain part is $20.00 per unit for 100 units .The part can be produced in the companys own plant for $28.00. The components of making the part are as follows : Unit raw material cost = $8.00 per unit Direct labor cost =6.00 per unit Labor overhead at 150%=9.00 per unit Equipment fixed cost =5.00 per unit _ Total =28.00 per uniit Factors in the Make or Buy decision Factor Explanation and Effect on Make/Buy DecisionHow do part costs compare?This must be considered the most important factor in the make or buy decision.However,the cost comparision is not always clear续表：Is the process available in-house?If the equipment and technical expertise for a given process are not available internally,then purchasing is the obvious decision .Vendors usually become very proficient in certain processes ,which often makes them cost competitive in external-internal comparisons .However ,there may be long-term cost implications for the company if it does not develop technological expertise in certain processes that are important for the types of products it makes. What is the total production quantity? The total number of units required over the life of the product is a key factor .As the total production quanity increases ,this tends to favor the make decision .Lower quanities favor the buy decision. What is the anticipated product life?Longer product life tends to favor the decisionIs the component a standard item?Standard catalog items (e.g.,hardware items such as bolts ,screws,nuts ,and other commodity items )are produced economically by suppliers specializing in those products .Cost comparisions almost always favor a purchase decision on these standard parts Is the supplier reliable ?A vendor that misses a delivery on a critical component can cause a shutdown at the companys final assembly plant .Suppliers with proven delivery and quality records are favored over supplies with lesser records .Is the companys plant already operating at full capacityIn peak demand periods ,the company may be forced to augment list own plant capacity by purchasing a portion of the required production for external vendors续表：Does the company need an alternative supply source?Companys sometimes purchased parts from external vendors to maintain an alternative source to their own production plants .This is an attempt to ensure an uniterrupted supply of parts ,e.g.,as a safeguard against a wildcat strike at the companys parts production plant. Should the component by bought or made in-house?Solution :Although the vendors quote seems to favor a buy decision ,let us consider the possible impact on plant operations if the quote is accepted.Equipment fixed cost of $5.00 is an allocated cost based on investment that was already made .If the equipment designed for this job becomes unutilized because of a decision to purchase the part ,then the fixed cost continues even if the equipment stands idle .In the same way ,the labor overhead cost of $9.00 consists of factory space ,utility ,and labor costs that remain even if the part is purchased .By this reasoning ,a buy decision is not a good decision because it might be cost the company as much as $20.00+$5.0+$9.00=$34.00 per unit if it results in idle time on the machine that would have been used to produce the part .On the other hand ,if the equipment in question can be used for the production of other parts for which the in-house costs are less than the corresponding outside quotes ,then a buy decision is a good decision ., Make or buy decision are not often as straightforward as in this example .The other factors listed in Table also affect the decision .A trend in recent years ,especially in the automobile industry ,is for companies to stress the importance of building close relationships with parts suppliers .We turn to this issue in our later discussion of concurrent engineering.Computer-aided Process Planning There is much interest by manufacturing firms in automating the task of process planning using computer-aided process planning (CAPP) systems .The shop-trained people who are familiar with the details of machining and other processes are gradually retiring ,and these people will be available in the future to do process planning .An alternative way of accomplishing this function is needed ,and CAPP systems are providing this alternative .CAPP is usually considered to be part of computer-aided manufacturing (CAM) .However ,this tends to imply that CAM is a stand-along system .In fact ,a synergy results when CAM is combined with computer-aided design to create a CAD/CAM system .In such a system ,CAPP becomes the direct connection between design and manufacturing .The benefits derived from computer-automated process planning include the following: .Process rationalization and standardization .Automated process planning leads to more logical and consistent process plans than when process is done completely manually .Standard plans tend to result in lower manufacturing costs and higher product quality. .Increased productivity of process planner . The systematic approach and the availability of standard process plans in the data files permit more work to be accomplished by the process planners. .Reduced lead time for process planning . Process planner working with a CAPP system can provide route sheets in a shorter lead time compared to manual preparation . .Improved legibility . Computer-prepared rout sheets are neater and easier to read than manually prepared route sheets. .Incorporation of other applicaton programs. The CAPP program can be interfaced with other application programs,such as cost estimating and work standards. Computer-aided process planning systems are designed around two approaches.These approaches are called : (1) retrieval CAPP systems and (2) generative CAPP systems .Some CAPP systems combine the two approaches in what is known as semi-generative CAPP. Concurrent Engineering and Design for Manufacturing Concurrent engineering refers to an approach used in product development in which the functions of design engineering ,manufacturing engineering ,and other functions are integrated to reduce the elapsed time required to bring a new product to market, Also called simultaneous engineering ,it might be thought of as the organizational counterpart to CAD/CAM technology.In the traditional approach to launching a new product ,the two functions of design engineering and manufacturing engineering tend to be separated and sequential,as illustrated in Fig (a).The product design department develops the new design ,sometimes without much consideration given to the manufacturing capabilities of the company ,There is little opportunity for manufacturing engineers to offer advice on how the design might be alerted to make it more manufacturable.It is as if a wall exits between design and manufacturing.When the design engineering department completes the design ,it tosses the drawings and specifications over the wall ,and only then does process planning begin.Product designManufacturing engineering and process planning Production and assemblyThe “wall” between design and manufaturingProduct launch time,traditional design/manufacturing cycleDifference in product launch time(a)Traditional product development cycleProduct designSales and marketingQuality engineeringVendorsManufacturing engineering and process planningProduction and assemblyProduct lauch time,concurrent engineering(b) product development using concurrent engineering Comparision : (a) traditionnal product development cycle and (b) product development using concurrent engineering By contrast,in a company that practices concurrent engineering ,the manufacturing engineering department becomes involved in the product development cycle early on ,providing advice on how the product and its components can be designed to facilitate manufacture and assembly.It also proceeds with early stages of manufacturing planning for the product .This concurrent engineering approach is pictured in Fig (b). In addition to manufacturing engineering ,other function are also involved in the product development cycle ,such as quality engineering ,the manufacturing departments ,field service ,vendors supplying critical components ,and in some cases the customer who will use the product .All if these functions can make contributions during product development to improve not only the new products function and performance,but also its produceability ,inspectability ,testability ,serviceability ,and maintainability .Through early involvement ,as opposed to reviewing the final product design after it is too late to conveniently make any changes in the design ,the duration of the product development cycle is substantiallly reduced. Concurrent engineering includes several elements: (1) design for several manufacturing and assembly,(2) design for quality ,(3)design for cost ,and (4) design for life cycle .In addition ,certain enabling technologies such as rapid prototyping ,virtual prototyping ,and organizational changes are required to facilitate the concurrent engineering approach in a company. 中文翻译工艺规程制订与并行工程产品设计是用于产品及它的部件装配的计划. 为了把产品设计转换成一个物理实体 ,需要一个制造规程。制订这样一个计划的活动就叫做工艺规程制订。它是产品设计和制造之间的连接.工艺规程制订包括决定加工顺序和制造产品所必须完成的装配步骤.在以下文章中,我们将解释工艺规程制订和他的一些相关主题。在开始, 我们应该区别在下列文章中被反复提到的工艺规程制订和生产计划。工艺规程制订与如何制造产品和它的零件等工程技术问题有关.制造零件和装配产品需要什么样的设备和工具? 生产计划与产品制造物流管理有关系。它在工艺规程制订后面，与原料分类及获得满足制造充分数量产品要求的资源有关.工艺规程制订工艺规程制订包括决定最适当的制造及装配步骤和顺序,在这些顺序和步骤中他们必须根据所提出的详细的设计说明书规范完成给定零件或产品的制造. 能够被计划的工艺范围和多样性通常由于公司车间可用设备和技术能力而受到限制.在公司内部不能够制造的零件必须到外部市场购买. 工艺规程制订所提及的工艺选择同样也受到详细设计资料的限制.我们稍后将会回到这一点.工艺规程制订通常是由制造工程师完成的.( 工业工程师拥有其他权利.) 工艺制订者必须熟悉工厂中详细可用的制造流程并且能够说明工程图。基于制订者的知识，技术和经验, 用于制造每个零件的工艺步骤以最合乎逻辑的顺序被发展制订。下列各项是在工艺规程制订范围里的许多决定和详细资料: .设计图的说明. 在工艺规程制订的开始,产品设计的这一部分( 材料，尺寸，公差 ,表面处理,等等)必须进行分析。 .工艺和工序. 工艺制订者必须选择哪一个工艺是必需的及必需工艺的序列。此外还必须准备好一个简短的工艺步骤描述. .设备选择. 大体上,工艺制订者必须逐步展开利用工厂现有机器的计划.另外,组件必须被购买或在新设备上的投资必须被制定. .工具,冲模,铸模,夹具,量具. 工艺必须决定每个工序需要什么工具.这些工具的实际设计和制造通常通过委派工具设计部门和工具库或者联系专攻那种工具制造的外面厂商来完成. .方法分析. 车间规划,小工具,提升重物的提升间,甚至在一些人工操作情景中的肢体动作也被指定. 工业工程处通常对这个工作负责. .操作步骤. 工作测量技术被用来为每个操作设定时间标准。 .切削工具和切削条件. 这些必须对加工操作通过推荐标准手册来进行详细说明.零件工艺规程制订对于单个零件,加工顺序通过一种被称为进路表的表格来进行文件证明备份. ( 不是所有的公司使用进路表这个名字；另外的一个名字是 操作说明书。”)就如工程图被用于详细说明设计产品一样,进路表被用于详细说明工艺计划. 他们是类似的, 一个用于产品设计 , 另一个用于制造。典型的进路表 ,包括下列信息: (1)所有工作部分要执行的操作都按照他们应当被执行的顺序列出来;(2)一个指出关于零件图尺寸公差必须完成加工的每个操作的简短描述;(3)用于完成这个操作的特定设备;(4)像冲模,钻模,切削刀具,钻夹具或夹具,和量具这样的特定工具.一些公司还包括时间设置,周期标准和其他数据.他被称为进路表是因为工艺顺序规定了零件在工厂中必须遵循的路线. 决策过程中被用来借鉴的部分在很大程度上依据起始原料.这起始原料是由该产品设计者选定.一旦原料已被指定，各种可能的加工操作是大为缩短.该产品设计师对起始原料功能水平的选择，主要基于经济和生产能力的限制.制造单个零件的典型加工顺序包括: (1) 一个基本工序,(2) 二级工序,(3) 提高物质特性工序,和(3) 最后工序.一个基本工序决定了工件的起始造型.金属铸件,塑料成型,金属精炼是基本工序中的实例. 起始造型常常必须通过改变起始造型操作(或者接近于最终造型)的二级工序来精制. 二级工序习惯于和基本工序一起提供起始造型.当砂型铸造是基本工序,车加工通常是二级工序.当轧钢厂制造金属片是基本工序,冲压操作象冲裁和弯曲通常是二级工序.当塑料注入成型是基本工序时,二级工序通常是不必要的,因为他的大多数几何特征制造通过别的方式如成型制造来完成.塑料成型和其他操作的二级工序被称为净成型工序的并发二级工序.需要一些但并不多的二级工序的操作就是所提到的近似净成型工序.许多有印象的摸锻件就是这一类.这类零件能够经常在锻造(初级工序)阶段被成型,因此减少了必要的加工(二级工序).一旦模型被建立,许多零件的下一步是改良它们的机械物理性能.提高特性工序并不改变零件模型,然而,它却能改变零件的物理特性.金属零件的热处理操作就是最普通的实例.类似的如玻璃通过热
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