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Machine Downtime improvements

Six Sigma – iSixSigma Forums Old Forums General Machine Downtime improvements

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  • #37495

    Ward
    Participant

    I am currently putting together a green belt project charter for a maintenance manager. Both the maintenance manager and myself are in agreement that we need to reduce down time due to machine break downs through a series of improvement activities / projects. Unfortunately we are in disagreement over the level of improvement that we should be aiming for.
    Does anyone have a example of world class benchmark for machine down time reduction due to break downs.
     

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    #110496

    RAC
    Participant

    Machine break down, world class manufacturer ?  these are pretty broad categories.  What industry are you in?
     
    RAC

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    #110503

    Diorio
    Member

    Here is some data for you, (US and UK)
    Percentile                                  25    50     75      90   95
    Equipment Availability %           78    84     92     94    98
    Equipment Availability = actual uptime/required uptime
    Also suggest you look at OEE as a measure.
    Please bear in mind this is general industry….there are indexes to adjust for industry type.
     
    Rich

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    #110504

    Ward
    Participant

    Plastic injection moulding.
    Injection moulding range of 250 tonnes to 1500 tonnes.
    Home storage solutions.

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    #110509

    Joe BB
    Participant

    As an engineer, I love when maintenance managers get involved in 6s!
    Personnally though, I don’t like leading projects that “Reduce Mechanical downtime” as a metric, mainly because this is hard to measure, and the causes cannot always be controlled. A strong preventative maintenance program is the answer for that.
    In our food processing facility, we run 24/7 and our mechanical downtime is at 1.5%. However, in a paper mill for example, downtime could be as high as 20% (what industry are you in?). Instead, maybe you could look at mean time between a specific type of failure, whose causes are known, as opposed to a general downtime %.
    If you are looking for a good starting project for a maintenance manager, I recommend looking at time on tools for your tradespeople (reduce O/T by being more efficient) or “right-sizing” your spare parts inventories, or even looking at your shutdown schedules to see if you can decrease the duration and get the same amount of work completed.
    Good luck,
    Joe BB
     
     
     

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    #110515

    Mike Carnell
    Participant

    Pete,
    If you take the metric began with at Motorola we had to get a 10X improvement every 2 years (approx 68% reduction per year). It worked well but as any glittering generalization it is easy in some situations (low capability) and difficult in others (high capability).
    First you are doing your managers job. he should be writing the charter. Aside from that don’t worry about it until you get some data. Find some catagories lower than “reduce down time.” If you are at a lower level you will have a little more visibility of what is possible.
    Just my opinion.
    Good luck

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    #110527

    Chris Seider
    Participant

    Pete,
    Do not let the others shy you away from addressing machine availability.  For an extrustion facility, one of our machines has a lot of unplanned downtime.  This was always tolerated until a little analysis showed a common failure for 40% of those unplanned occurrences.  A team was launched and that 40% of the unplanned occurrences was reduced drastically–over 50%.  However, we are not running into a proven raw material supplier causing unplanned downtime and are having to work strongly with the supplier to shape up or ship out.
    A simple metric for machine downtime is the # of occurences of short stops or breakdown for a certain time frame.  If you have some data collected already, look for commonality and tackle that first level pareto issue. 
    Good luck!

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    #110530

    Gourishankar
    Participant

    Pete
    First you should freeze the metrics you would use to measure machine downtime . OEE ( overall equipment effectiveness ) is a good but broad indicator of the machine utilization % .
    Two significant metrics you can use are MTBF ( mean time between failures ) and MTTR ( mean time to repair). While the first is an indication of the Effectiveness of the maintenance process ( preventive , predictive , breakdown processes ) , the second  is a good measure of the Efficiency of the maintenance process . You should be targetting improvement in both areas.
    The level of improvement can be decided once you establish a baseline sigma for the above metrics. Of course , the ideal target should be 6s!!
    You could also consider “industry” benchmark data – it may not be wise to use data general downtime data as it varies from process to process.
     

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    #110540

    Diorio
    Member

    Hi Gour….,
    After giving more thought to Pete’s issue and considering your point. It would seem that MTTR and MTBF data is actually difficult to collect accurately. Easy to game, tremendous variability in data entry practices.
    Would it make more sense to look at a proactive to reactive maintenace ratio, as a bellwether for maintenace. But of course there is another problem….minor stop off’s handled by operators often un- documented as to cause but usually recorded as downtime.
    Therefore another Y could be a ratio of minor stoppage to downtime from all sources. My thinking is if MTBF and MTTR are improving then these two metrics would show it.
    Food for thought.
    Rich
     
     
     

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    #110565

    Mike Carnell
    Participant

    Gourishankar,
    Tracking MTBF and MTTR without tracking Availability will lead you to missed opportunities. When you understand demand and Availability you can trade off Availability to work on MTBF.
    Regardless of that these metrics are 30,000 foot metrics and not projects. These are Y’s and they are a function of specific issues around the machines. It may be a good spot to begin looking but these are not projects.
    Just my opinion.
    Good luck.

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    #110657

    Gourishankar
    Participant

    Rich
    I agree with you. Data accuracy  is an issue . I don’t think secondary data can be used for meaningful analysis.Maybe a data collection exercise needs to be carried out for sepcifically for the project.
    Mike has made a good point on MTBF and MTTR , although I am not clear how Ys could be generated out of MTBF /MTTR data. I think at best you may be able to drill down the same to machine- specific or process – specific data .
     
     

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    #110665

    Gourishankar
    Participant

    Mike
    You’ve made a good point on the metrics. Can you suggest a typical Y ? I think a Pareto of MTBFs/MTTRs will yield machine – specific or process specific improvement opportunities that can be converted into Ys.
    I have tried this in one situation and come up with significanlty high MTBFs and MTTRs for bearing – related maintenance. Two opportunities identified were  ” x % reduction in bearing consumption” and  “a% reduction in downtime due to bearing  failures”. A second order Pareto will further indicate specific parts of the machine or process that will require improvement.
    However , as mentioned in an earlier post , data accuracy for MTTRs and establishing baseline sigma are major issues.
     

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    #110678

    Mike Carnell
    Participant

    Gourishankar,
    If you will reread your postagain you just provided your own example. MTBF was not he project. The projects were bearing consumption and bearing failures – the independent x’s (they may even become Y’s.
    MTBF and MTTR will always be a Y. You don’t want to convert things to Y’s you want to convert them to x’s
    Good luck
     

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    #110926

    PharmBB
    Participant

    I am just wondering if someone has statistics for Packaging changeover (set-up ) time for pharmaceutical industry , Also the packaging line downtime as industry world class performance.
    Thanks
    PharmBB

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    #110929

    Vik Sharma
    Member

    We have an excellent reporting software that was customized to capture key metrics for all the equipment at our facility.  This reporting package records machine uptime, downtime, faults and key prodution counts.  From recording all these measure it reports the following:

    Machine Availability
    Mean Time To Repair
    Mean Time Between Failure
    Overall Equipment Effectiveness
    The vendor is Sidel, the application is called Efficiency Improvement Tool.  It is developed by their group in Montreal, Canada.  If you need to capture machine data they have the an excellent package.  The only downside in that they do not currently have SPC capability built-in.
     

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    #110930

    Germán
    Participant

    Pete:
    I also work in a plastic injection molding plant (50 machines from 60 to 350 tons, PP water pipe fittings)
    Here you have some benchmarks. source: http://www.immnet.com/articles?article=945
    Best Regards

     
     

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    #110939

    Adolfo
    Participant

    I would recommend to do a Kizen exercise and take note of activities/attitudes on  more common activities where yuo have break down. Then modify this activitie involving opertors and maintenece people. This is faster.
    adg.

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    #110944

    Jonathon Andell
    Participant

    I did some work in injection molding too. Our shops tenbded to be lower tonnage, making multi-cavity small items. Here are some things to bear in mind as you move forward.It sounds like your management may be trying to “end world hunger” with a single project. Break out your down time categories. There is down time for change-over, for preventative maintenance, and for breakdowns. You can be maintaining either the press or the mold, so you want the breakdowns to reflect that.Once you start assigning down time to the respective categories, you can build a Pareto chart to see where your effort is spent best.If you need to speed changeovers, Shingo’s work on “Single Minute Exchange of Die” could provide some good insights.If you want to reduce breakdowns, you probably will need still deeper breakdowns of repair cause categories. Eventually, you will get specific: X hours of preventive mainetnance on such-and-such category will return Y hours of additional up time. Then you can see whether prevnetive maintenance can be built into other times when a unit is down – for instance, maybe you can maintain a press while a mold is being changed out for repair, and so on.Until you know what the “as-is” condition looks like, however, it is inappropriate to establish a goal. Each category, and each kind of break down, has its own range of as-is and could-be performance.Hope this helps!

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    #110946

    DHogue
    Participant

    Maybe the place to start your thinking is that the 6 sigma level with respect to a 24 X 7 X 365 operating machine schedule is about 107 seconds per year.  Compute the six sigma level on your machines (99.99966%) using the best ideal operating schedule & compare with where you are.  Then set the goal level at any future state sigma level you want to be. Evaluate your improvement investments accordingly. 

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    #111024

    Abdelaziz Moustafa
    Participant

    Hello
     
    I would like to know how do you measure overall equipment availability…
    OEE (i need to know the equation)
     
    Thank you

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    #111025

    Abdelaziz Moustafa
    Participant

    Hello all
    I have a project of machining process lost hours…can anyone recommends what data i can collect to identity the critical cause not satisfying my Y’s
    Thank you
    Abdelaziz

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    #111030

    Vik Sharma
    Member

    Check out the link below for a good explaination
    http://www.bin95.com/Overall_Equipment_Effectiveness_OEE.htm
     

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    #111249

    Subramanian
    Member

    machine downtime calculation method,
    the calculation method and how to make graph.

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    #111251

    Subramanian
    Member

    machine downtime calculation method,
    the calculation method and how to make graph.

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    #112627

    Abdelaziz Moustafa
    Participant

    Hello
    I found that we lose 15% of the machine time every week in setup including the qulaity approval process and first piece approval….does anyone can give me an idea on how to collect data for Hypothesis, SPC, Multi var., and could help me in my DOE.
    Thank you ALL 

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