8D Instuctions -8D 解决问题方法的指导.doc

d 1team approach when a problem cannot be solved quickly by an individual , it is necessary to form a team. model for effective teamwork - structure - goals- roles - procedures- interpersonal relationships brainstorming a method for developing creative solution to problems. it works by focusing on a problem.no criticism of ideas the idea is to open up as many possibilities as possible, and break down preconception about the limits of the problem. team organizationcross-functional- design engineering - quality assurance- purchasing- manufacturing engineering- material control- sales / marketing- etcroles in a team leader : a person that lead the team by sets/directs agenda. champion : guide, direct, motivate, train, coach, advocate to upper management. record keeper : write and publishes minutes. participants : that involve in activity. facilitator : encourage / drive / stimulate the team.d 2describe the problem specify the internal / external customer problem by identifying in quantifiable terms the who , what , when , where, why , how , how many ( 5w2h ) for the problemproblem definition is the basic of problem solving. used during the brainstorming sessions to identify the potential causes.part of the problem solving process is to identify the root cause of the problem and understand why it existed in the first place.the root cause is the reason the problem exists. operational definition of the problemit is important that the problem be described in terms that have the same meaning to everyone.an operational definition consists of verifiable criteria that have the same meaning to the production workers , manager, customer, engineer, buyer, technician ,team members .etc and used for past ,present and future comparisons and analysis.symptoms vs. cause it is uncommon for problem to be reported as symptoms - noise , wont work , no power , machine down , broken tool, head froze up , contaminated , rough surface , shortage of parts , quality problem , worn out , line stopped , not to specification , labour problem , management problem , too much variation , etc.problem solving systematic approach to problem solving :- business as a system ( business as a process )- analytical problem solving - process flowproblem analysis methodologies : -5w2h-stratification-comparative analysis / similarity analysis key question 5ws and 2hs -who? what? where? when? why? how? how many?5w 2h analysiswho? identify individual associated with the problem. characterize customer who are complaining. which operator are having difficulty? what? describe the problem adequately. does the severity of the problem vary? are operational definition clear ( e.g defect) is the measurement system repeatable and accurate?when? identity the time the problem started and its prevalence in earlier time periods. do all production shifts experience the same frequency of the problem? what time of the year/day does the problem occur?where? if a defect occurs on a part, where is the defect located? a location check sheet may help. what is the geographic distribution of customer complaints?why? any known explanation contributing to the problem should be statedhow? in what mode or situation did the problem occur? what procedure were used?how many? what is the extent of the problem? is the process in statistical control?stratification analysis stratification analysis determine the extent of the problem for relevant factors. is the problem the same for all shifts? do all machines , spindle , fixtures have the same problem? do customers in various age groups or parts of the country have similar problem? problem flowroot cause analysisdescribe the problem phasesphase 1- state the symptom, extent and consequence of the problem.- prepare / review process flow diagram.- start and action plan to define the problem. identify who will do what by when.describe the problem phasesphase 2- identify who, what , where, when, why, how and how much.- qualify the extent of the problem to help identify relevant stratification factors.- evaluate similar situations where the problem might be expected to occur.- use all available indicators. be creative about these.- subdivide the problem into natural problem group.describe the problem questionquestions what type of problem is it ?- field complaint - quality improvement- manufacturing improvement- component design- labour / personnel- supplier / vendor- cost improvement- solution implementation- cross functional describe the problem 5w-2hwho, what, when, where, why, how, how many - what is the extent of the problem?- has the problem been increasing, decreasing or remaining constant?- is the process stable?- what indicators are available to quantify the problem?- can you determine the severity of the problem? can you determine the various costs of the problem? can you express the cost in percentage, dollars, pieces, etc.? describe the problem 5w-2h-do we have the physical evidence on the problem in hand?-have all sources of the problem indicators been identify and are they being utilized?-have failed parts been analyzed in detail?remember system how it worksdesign what its made of process how its made understanding your process and systemsuse a process flow chart ! because : you want to understand you current process. you are looking for opportunities to improve. you want to illustrate a potential solution. you have improved a process and want to document the new process. creating a process flow chart identify the process or task you want to analyze. define the scope of the process. ask the people most familiar with the process to help construct the chart. agree on the starting point and ending point. agree on the level of detail. always start with less detail. creating a process flow chart look for areas for improvement identify the sequence construct the process flow chart analyze the result d 3 implement and verify interim (containment) action - objective - define and implement containment action to isolate the effect of the problem from internal and external customers until corrective action is implemented.- verify the effectiveness of the containment action(s).contain flowcontainment action common containment action include :-100% sorting of components-units inspected before shipment-parts purchased from a supplier rather than manufactured in -house-tooling changed more frequently-single source containment action - unfortunately , most containment action will add significant cost“ money” to the product.- the danger of many interim corrective actions is that they are considered to be a permanent solution to the problem overtime.“ containment action typically address the effect. they should be considered “immediate first-aid to be reviewed and removed as quickly as possible.containment action containment action should proceed in parallel with the root cause determination investigation. during this time many useful things must be pursued as a first step in finding the root cause. establishing an investigative plan obtaining baseline data initiating an on-going control system developing a follow-up and communications system correcting product already produced start systematic investigation conduct special studies and statistical experiment understand the problem forecast the future containment action - use check sheet , control charts , etc to evaluate the effectiveness of the actions. the process can be monitored using control charts and histograms. the action plan should define who, what and when clearly to coordinate the interim fixes.- ask what would be the effect of : incorporating robust designs centering the process improving machine set-up changing tooling determining how one operation or dimension effect anothercontainment action flowverifying containment actions pilot runsrun pilot tests artificially simulate the solution to allow actual process or field variation. field test the solution using pilot customer groups verify carefully that another problem is not generated by the solution.verifying containment actions pilot runsmonitor result quantify changes in the indicators. user evaluationcontainment actions verification questions have all alternatives been evaluated? are responsibilities clear and defined? is the required support available? when will the actions be completed? have you ensured that implementation of the interim solution will not create other problems?d 4define and verify root cause identify all potential causes which could explain why the problem occurred. isolate and verify the root cause by testing each potential cause against the problem description and test data. identify alternate corrective actions to eliminate root cause.two root causes root cause of event ( occur or occurrence )what system allowed for the event to occur? root cause of escapewhat system allowed for the event to escape without detection?control chart analysis reaction check a wide range of data and control chart, if a special cause or non-random patterns is suspected action should be taken.-accurately completed -check the pair x-bar and r-barcontrol chart analysis reaction investigate the process operation to determine the cause.-use tools such as:- brainstorming cause and effect pareto analysiscontrol chart analysis reaction your investigate should cover issues such as :- the method and tools for measurement the staff involved changes in material machine wear and maintenance mixed samples from different people or machine incorrect data, mistakenly or otherwise changes in the environmentcontrol chart analysis reaction act to decide on appropriate action and implement it. identify on the control chart. the cause of the problem the action taken try to eliminate the possibility of the special cause happening again. continue monitoringdefine and verify root cause (s) use a cause and effect diagram to brainstorm all potential causes of the descried problem. 4m1e process flow stratification existing data should be reviewed for clues to potential causes. timeline analysis will identify event occurring about the time the problem developed.define and verify root cause (s)“ what changed ? ” “ when? ”are important questions.define and verify root cause (s) a technique used extensively is analytical problem solving is a “comparison analysis”what is and what is not conduct a survey asking why repeatedly is effective in driving the process towards root cause.six steps of investigation state how the potential cause could have resulted in the described problem. establish what type of data can most easily prove or disprove the potential cause. develop a plan on how the study will be conducted. identify the actions on an action plan. prepare the required material to conduct the study. training may also be required.six steps of investigation analyze the data. use simple statistical tools emphasizing graphical illustrations of the data. state conclusions. outline conclusions from the study. does the data establish the potential cause as being the reason for the problem?define and verify root causeanalyze what has changed manufacturing new supplier ? new tools ? process changed ? measurement system ? raw material ? vendor supplied parts ? do other plants have a similar problem ?analyze what has changed engineering any pattern to the problem ? geographically ? time of year ? build date ? did the problem exist at program sign-off ? was it conditionally signed off ? did the problem exist during eb/pp functionals ?errors almost all errors are caused by human error. forgetfulness errors due to misunderstanding error in identification errors made by expertserrors almost all errors are caused by human error. inadvertent errors errors due to slowness errors due to lack of standards surprise errors intentional errorsprocess failure causes omitted processing processing errors errors setting up work pieces missing parts wrong parts processing wrong work piece mis-operation adjustment errors equipment not set up properly tools and/or fixtures improperly prepared process failure causes poor control procedure improper equipment maintenance bad recipe fatigue lack of safety hardware failure failure to enforce control environment poor fmea(s) stress connection potential causes - questions have you identified all sources of variations on the flow diagram? have all courses of information been used to define the cause of the problem? do you have the physical evidence of the problem? can you establish a relationship between the problem and the process?potential causes - questions do you continually challenge the potential root cause with the question why followed with because to construct alternatives? what are the is / is not distinctions? is this a unique situation or is the likely problem similar to a past experience?potential causes - questions has a comparison analysis been completed to determine if the same or similar problem existed in related product? what are the experience or recent action that may be related to this problem? why might this have occurred? why havent we experienced this problem before?d 5choose , implement & verify corrective action through pre-production test programs quantitatively confirm that the selected corrective actions will resolve the problem for customer, and will not cause any undesirable side effects. define contingency actions, if necessary, based upon risk assessment. choose , implement & verify corrective action whatever verification you choose , a detailed verification / action plan is required to outline who will be taking what action by when.choose , implement & verify corrective action run pilot tests artificially simulate the solution to allow actual process or field variation. field test the solution using pilot customer groups. verify carefully that another problem is not generated by the solution.choose , implement & verify corrective action monitor results quantify changes in key indicators stress the customer / user evaluation confirmation question can you list and measure all of the indicators related to the problem? which of the indicators are most directly related to the problem? can you use the indicators to measure problem severity? can you determine how often or at what interval to measure the problem ( hourly / shift / daily / weekly / monthly )?confirmation question if there are no changes to the indicators after taking action, can you determine what to do? will you need to take cause , action and verification measures ? do all indicators reflect conclusive resolution ? has the team prioritized the customer / user evaluation after implementation ? what scientific method are being used to verify effectiveness in the short term and to predict the outcome long term ?verification question has the customer been contacted to determine a date when verification will be evaluated ? what data has been established for follow-up ? has a time-line (project) chart been completed ? have field tests been conducted using pilot customer group ? have dates been established when verification of effectiveness will be evaluated ?d 6implement permanent corrective actions define and implement the appropriate corrective action(s). choose on-going control to ensure the root cause is eliminated. once in production, monitor the long term effects and implement contingency actions ( if necessary )implement permanent corrective actions once the root cause have been identified, the team establishes an action plan on the permanent action to be taken. again, the action plan includes who will do what by when.corrective actions questions do the actions represent the best possible long-term solution from the customers viewpoint ? do the action make sense in relation to the cycle plan for the product ? has an action been defined ? have responsibilities been assigned ? has timing been established ? has required support been defined ? what indicat