下载文档原格式
Parker Lean System Poka-YokeObjective•Define Poka-Yoke•Describe the purpose of Poka-Yoke•Given a work scenario, describe examples of how Poka-Yoke could be employed.•Distinguish the difference between mistake proof and fail safe•Describe the ideal approach of Poka-Yoke.•Describe characteristics of Poka-Yoke solutions.•Given examples of Poka-Yoke solutions, identify what is good and what could be improved.Poka Yoke•POKA -inadvertent error•YOKE -proof•Pronounced (POH-kah YOH-kay)In the original Toyoda Loom, Jidoka was the principle of stopping work immediately when a defect occurred. Poka Yoke was the device that made it possible.Original Toyoda Loom -JidokaSources of Defects•Inappropriate process specifications •Excessive process variability •Material properties and variability •Machine performance and variability •Inadvertent errors–Humans or machinesErrors Vs. Defects•Product defects result from errors and mistakes •Errors and mistakes will always be potential issues with operations involving people •Machines can make mistakes tooWe can achieve Zero defects by catching these errors and mistakes and preventing themfrom becoming product defectsErrors Vs. DefectsMistakes (errors) are inevitable“A human is an animal that makesmistakes”--Shingo1001 in 110-11 in 1010-21 in 10010-310-410-510-6(Highest)(Lowest)Crew reaction duringair disasterSimulated militaryemergencyPassive inspections(general walk -arounds )Monitor/inspector fails to recognize initial error by operatorSimple arithmetic errors (without re -doing calculation on separate paper)Missetting largemanual values (nostatus indication except open orclosed)Technician “seeing ”an out of calibration instrument as “intolerance ”General error of omission (no control room display)General error of omission for itemsembedded inprocedureSelection of switch dissimilar in shapeor location todesired switchMissetting large manual valves (controlled by procedure keys, chaining, etc.)Selection of key operated switch rather than non -key switch (does not include error of decision)General errors of commission (e.g., misread label and selected wrongswitch)Upper limit to credibility Two -man team (one do; one check then reverse roles)SOURSE: System Safety 2000, Joe Stephenson (New York: Van Nostrand Reinhold, 1991)Human Error RatesPoka Yoke•Makes permanent changes to equipment,operations, or procedures to eliminateopportunity for error•Provides an immediate signal if a mistakeoccursMistake Proof & Fail Safe Mistake Proof / Fail Safe techniques are partof a Poka-Yoke system•Mistake Proof –Practices and devices thatmake it easy to do it right and difficult orimpossible to do a task wrong.•Fail Safe –If anything does go wrong, itimmediately becomes impossible tocontinue (Jidoka)Ideal Function of Poka-Yoke Linkage to Jidoka and a Zero defect system •Source inspection to detect errors at theirsource•100% inspection for errors/mistakes anddefects using inexpensive sensing devices •Immediate action to stop operations when an error is detectedContact Sensors•Used to physically detect the presence or absence of an object or feature.•Used to physically detect the height orposition of a part or dimension.Impact of Poka YokeState of Defect Source Informative InspectionRegulation Impact Predicted ShutdownAnnunciationLine StopFeedback &Adjust WarningAnnunciationZero Defects (Defect Prevention)Detected Scrap & Rework(Defect Reduction)SameMistake Proof3.5 inch diskette. The diskettecannot be inserted unless it isoriented correctly. This is as faras a disk can be inserted upside-down.The beveled corner of thediskette pushes a stop in the diskdrive out of the way allowing thediskette to be inserted. Thisfeature, along with the fact thatthe diskette is not square,prohibits incorrect orientation.Mistake Proof110 volt outlets in NorthAmerica. All “grounded”items have a thirdprong that only fits oneway in the receptacle.Even two prong /ungrounded items thatare polarity sensitivecan be forced to beplugged in the sameway due to differentsized prongs on boththe plug and outlet.Here is a parts kit for an assembly operation. Can you easilytell if we have all of the right parts? Signed Packing ListMistake ProofMistake ProofThis bathroom sink has asmall hole near the top thathelps prevent overflow.This is a parts kit for an assembly operation that uses a picture. Can youtell which parts have already been installed?Mistake ProofThis automatic coffee pot is equipped with a “pause and serve ”feature. When you remove the pot, the flow isinterrupted by this simple valve.Images from John Grout: /faculty/jgrout/pokayoke.shtml Fail SafeFail SafeA special coupling on gas pumps allows the line to break away and seal if somebody drives away.Mistake Proof & Fail SafeMistake Proof & Fail SafeSki Boots and Bindings.When a skier falls and a skicomes off, a “runaway ski”can cause serious injury. SkiBrakes prevent this fromhappening by automaticallyDowndropping down when the skiboot is no longer in thebinding. They also fold upautomatically when a skiersteps into their skis.RetractedCharacteristic of PokaYoke Solutions •Simple•Inexpensive•Integral part of the process•Placed at the source of errors–Point of transformation (Process Function)•Capable of 100% inspection•Provide quick feedback–(Effective human support system in place)•Ideas generally originate on the shop floor•Prevents process or part from moving forward if errors occur.Poka Yoke Aids•Colors and color-coding •Shapes / sizes •Symbols•Other toolsDegrees of Poka-YokeIs it hard or impossible to do something wrong?•Both meet the definition of Mistake Proof•Example: Color coding doesn’t make it impossible •Impossible to do wrong is always better•Layer techniques for maximum effectLayers of Mistake ProofTrailer plug. This isthe quick disconnectelectrical connectorused to hook up thelights on a trailer to atow vehicle. Thereare two layers of MPhere: color coding(white, green, yellow& brown wires) andthe physical shape ofthe connection.What’s good? How to Improve?This form uses mistake-proofing to help the user fill out the form correctly.ExerciseBreak into teams and develop Poka Yoke devices for:•Getting to this classroom•Making sure the lights are turned off•Making sure the computers are logged off•Making sure the room is locked•Making sure the students arrive on time•Other?Remember, layers are sometimes important!Homework。
P O K E –Y O K E愚巧法（防错）‐‐‐Six Sigma Series Training‐‐‐By Jack Zhu @ Feb‐20181Poke‐Yoke 介绍•POKA‐YOKE意为“防错防呆”，亦即Error & Mistake Proofing。
日本的质量管理专家、著名的丰田生产体系创建人新江滋生(Shingeo Shingo)先生根据其长期从事现场质量改进的丰富经验，首创了POKA‐YOKE的概念，并将其发展成为用以获得零缺陷，最终免除质量检验的工具。
2Poke Yoke 定义‐防错也叫防呆，是指通过设计种方法和程序，通过防错防呆技术和装置的应用，替代过去依赖工人•防错也叫防呆，是指通过设计一种方法和程序，通过防错防呆技术和装置的应用，替代过去依赖工人完成的重复劳动，消除产生差错的条件或者使出现错误的机会减少到最低，进而杜绝缺陷•因此，更具体的说，防错法是：1.具有即使有人为疏忽也不会发生错误的构造不需要注意力1.具有即使有人为疏忽也不会发生错误的构造---不需要注意力2.具有外行人来做也不会错的构造---不需要经验和直觉3.具有不管是谁或在何时工作都不会出错的构造---不需要专门的知识和高度的技能例如十字路口，要避免南北向行驶的车辆与东西向行驶的车辆相撞，有两种办法，一是设置红绿灯，二是建立交桥。
但是设置了红绿灯并不能完全避免南北向行驶的车辆与东西向行驶的车辆相撞，因为有很多的司机会违规驾驶，红绿灯只能起到告警作用。
但是如果建造了立交桥，就能完全避免相撞，这就是防错。
比较下：那种更好？比较一下：那种更好？3◆为什么要防错？•提升产品质量，达到质量0缺陷防错发消除了工人的作业困难的作业，防止失误的放生，消除缺陷，做到一次就把作业合格，消除返工与检验，提高产品质量检验提高产品质量•提升生产效率•减少对技能的依赖，降低工人劳动强度取代了依靠人的记忆，经验等制度规范行为，降低人为问题的发生概率，降低工作人员的劳动强度，对其取代了依靠人的记忆经验等制度规范行为降低人为问题的发生概率降低工作人员的劳动强度对其工作能力进一步解放•消除作业危险，提高安全保障◆何时防错？生产制造有三不原则，不接受、不制造、不传递不合格品•生产制造有三不原则，不接受不制造不传递不合格品•防错也是在这三个阶段4谁来防错？熟产肯定知产要素机料环测•熟悉生产的人肯定知道，生产6要素：人机料法环测•所以从这6个方面进行控制便能杜绝生产错误的发生•然而现实的情况是，除了自动装配的操作，其余所有的操作基本都是人做的•因此，防错主要指防止人产生错误，尽最大可能减少人为导致的错误此防错主要指防止人产生错最大能减少人为导致的错80% ！5◆关于错误和缺陷的概念●错误的定义：错误是预期过程的任何偏差，是人们由于疏忽，无意识等偶尔犯下的•人们犯错误是自然事件，是人都会犯错误，无意识的错误不仅是可能的，而且是难以避免的•机器并不是不犯错误●错误与缺陷•缺陷是错误的后果•所有的缺陷由错误产生•错误= 缺陷？不是所有的错误都产生缺陷6◆关于错误和缺陷的概念意图偏离后果缺陷过程的某一部分原因过程的某部分希望如何选择？所发生偏离的结果发生偏离的原因，一旦显示出一种偏离，一定有其因为错误是造成缺陷的原因因此可以通过消除或控制错误来预防缺陷的出可信的或者实际的原因●因为错误是造成缺陷的原因，因此可以通过消除或控制错误来预防缺陷的出现7错误产生的原因（8大基本原因）1. 忘记即忘记了某一个作业步骤，比如忘记在上螺丝之前装上垫片2. 对过程、作业不熟悉由于不熟悉作业过程和步骤，产生失误就在所难免，如让一个刚刚经过培训的新手去喷油漆，产生失误的概率比熟手肯定要大得多3. 识别错误识别错误是对工作指令，程序判断或理解错误所致。
防错防呆（PokaPoka-yoke）十大原理及其应用案例防呆防错的方法多种多样，智慧的人们总结出主要有如下10大原理：1、自动原理：光、电、力、化学等来进行自动化控制；& 保险丝超过电流，自动断电；& 麦当劳烘干机开启烘干按钮后，10秒钟自动停止；& 商场节能电梯在感应到重力后才会开始工作；& 自动点胶机在启动按钮后，每次自动注射等量的胶量；2、断根原理：从根本上排除可能发生的源头；& 为了祛除狐臭，医生往往采用切断大汗腺的方法；& 为了祛除蚊子，可以进行场地清洁，以除去滋生蚊子的温床；& 为了控制全世界人民，美国孟山都公司逐步控制了世界粮食专利（控制核心）；3、保险原理：必须有2个以上的动作同时开动才能继续执行下一步骤；& 操作人员必须双手同时启动2个冲床按钮才能操作，避免工伤事故；& 银行保险箱必须客户与银行工作人员同时打开才能取出物品；4、相符原理：确保两者形状、系统等特性匹配，来避免错误的发生；& 必须用对应的钥匙才能开门；& 登陆QQ或微博必须输入对应的账户和密码；& 规定渔网尺寸来避免鱼苗被打捞；& 医生手术会清点工具（确保工具槽是满的）来避免遗留患者体内；& 产品设计上采用形状匹配来避免操作人员匹配错误；5、隔离原理：远离危险现场，避免可能的错误；& 将危险品锁进柜子或放置高处，避免小孩误食；& 将不良品、嫌疑品进行隔离标识，以避免与良品混淆；& SMT刷锡膏及贴片必须在保护罩关闭以后才能工作；& 所有未校准或待维修的工具必须移除现场，进行隔离；6、顺序原理：避免顺序搞错而进行编号，可减少错误的发生；& 程序文件夹为避免取出后放错而进行斜线编号；& 儿童组装玩具通过编号组装可达到需要的形状；7、复制（确认）原理：也就是确认，可能是对我这辈子影响最大的就是“确认”；& 军队在上级向下级传达指令的时候，下级必须要复述，确保信息的正确传达；& 在信息传递时（如告知电话号码），需进行复述确认；& 在签订合同时，尽量采用一式几份，避免重复手抄出现错误；& 资料传递能够拷贝的尽量拷贝，避免人为手写错误；& 作业指导书可以指导操作员制造出相同品质的产品，并确保工作节拍的一致性；注意：在信息传递时，往往附带着一些隐性要求，需要进一步确认与要求的符合性；8、层别原理：避免将不同的工作做错，而设法加以区分；& 颜色管理，通过不同的颜色来识别对象状态；& 区域划分管理，避免不同区域间的混淆；& 工具按类别或配套管理，以匹配点检或使用；9、警告原理：如有异常发生，会自动以声、光、电提醒报警；& 电梯在超重情况下，会自动报警并停止工作；& 在安全带未系好时，汽车会自动重复报警；& 在出货扫描时，若发现与出货单不符，会自动警报提示；& 产线自动检测发现不良时，发出警报；10、缓和原理：无法排除问题的发生，但可采取措施降低损害程度；& 为了避免笔经常丢失，将笔用绳子绑在桌角；& 用保护膜保护产品，以避免产品被碰伤；所以，防呆防错法是一项非常贴切生活、工作的有效工具，在我看来是一项为人类作出巨大贡献的伟大发明。
