iSixSigma

Query for Maintenance

Six Sigma – iSixSigma Forums Old Forums General Query for Maintenance

Viewing 20 posts - 1 through 20 (of 20 total)
  • Author
    Posts
  • #42802

    Sanjay Joshi
    Member

    Hi All,
    I do not know whether this is right platform to ask this question or not, but still if any one has answer to this kindly help.
    When we calculate Mean Time Between Repairs(MTBR) for a Machine, it may happen that the Fault that happened now was different from the past date fault (For Example this time machine fuse blew off but last time the foundation bolt broke) so the time taken to repair these faults wont be same. Hence if i calculate the MTBR this wont show me the correct mean times.
    can anyone suggest a way to calculate the MTBR for different types of faults occuring on the same machine.

    0
    #135300

    Anshul Karoliwal
    Participant

    It depends on your project.
    There can be many ways to look at MTBR.
    Eg.
    1) MTBR per fault type – Various machines having same fault.
    2) MTBR per machine type – All machines of same make and type.

    0
    #135303

    Paul Gibbons
    Participant

    Hi Sanjay,
    My suggestion to you would be to forget about the MTBF and look at the Mean Time To Repair (MTTR) and the Mean Time To Failure (MTTF) both of which can be combined to claculate the MTBF should you so wish.
    From the MTTF you can see how effective your maintenance strategy is as a reliability KPI. From the MTTR you can see how effective your maintenance strategy is a maintainability KPI.
    I have experience a similar problem to the one you have described and this is what I did……
    Reliability modelling of groups of plant using the MTTF and MTTR data highlighted 4 machines that were critical to the business and not performing well. A review of the raw data informing the MTTR suggested a range of repair times between 20 and 9000 minutes. This suggested more than one failure mode existed and so further analysis was required. Using the Mean Rank Weibull analysis I plotted the ranked repair times on 3 decade Weibull paper. From the plot I could clearly see 3 distinct modes of failure.
    Taking the analyis further I carried out the median rank failure mode specific Weibull Analysis replotting the individual failure modes on 2 decade Weibull paper. From each plot I could see the Beta value and in this case the first two plots indicated normal wear out phase and the last plot indicated random failure.
    Checking the maintenance records I summarised the three separate modes of maintenance failure into the following categories:
    Mode 1 Minor stops for resetting alarms and changing fuses
    Mode 2 External repairs such as heater band changes and minor internal repairs such as injection screw smear head replcement.
    Mode 3 Major internal repairs such as injection screw breakage in barrel.
    Finally I calculated the financial cost of the failure modes identifying the focus for improvement within the overall maintenance strategy. In this case it was failure mode 3 which I calculated had cost £300k as apposed to failure mode 1 which I calculated had cost only £5k.
    I have the full Reliability, Availability, Maintainability & Safety (‘RAMS’) study written up as a Word file (although the Weibulls are ‘handraulic’ so you can’t see them on the word doc) if you want a copy post your email and I will send it to you.
    Good luck and if you need any advice on improving you maintenance engineering post a question and I will try and help.
    Paul

    0
    #135337

    Sanjay Joshi
    Member

    Thanks Paul,
    Thanks for your valuable suggestion.
    It would be of real help if you can send me the word document.My email id is [email protected]
    Regards,
    Sanjay Joshi
     

    0
    #135504

    BB
    Participant

    Hello Paul,
    Would appreciate if you could send me the word document too.
    My e-mail id is [email protected]
    Thanks, Krithish

    0
    #135505

    hari
    Participant

    Paul,
    Your reply to the post was very intresting, You seem to be a Guru in the Subject matter.
    Hari
     

    0
    #135506

    L B Subrahmanyam
    Participant

    Hi Mr. Paul,
    Please send me the word document to following mail
    [email protected]
    Thanks
    LBS
     

    0
    #135513

    Manish Kumar
    Participant

    Hi, Paul
    Your analysis is very objective and concluding. We have also started monitoring MTBF and will start TPM initiative shortly. I would be thank if you could send me the word documents too. My email is [email protected].
    Regards
    Manish Kumar

    0
    #135517

    Richard
    Member

    Hi,
    Could i have a copy of the word document too, please? My email id is [email protected]
    Thanks
    R

    0
    #135519

    Neha
    Participant

    Hello Paul
          I’ll appreciate it if you can provide me with the word document!.
      My e-mail is:  [email protected]
     
    Thanks

    0
    #135521

    WMatwijec
    Member

    Paul I would also be interested in your word doc.Walt
    MNAA
    Nashville Airport

    0
    #135527

    Curiel
    Participant

    Paul
    I would appreciate if you could send me the word document to my e-mail 
    [email protected]
    Thanks
    Enrique

    0
    #135547

    Cruz
    Participant

    Paul,
    I would appreciate if you can send me a copy of the document to my e-mail
    [email protected]
    regards
    Cruz

    0
    #135553

    sharad
    Member

    Hello Paul
          I’ll appreciate it if you can provide me with the word document!.
      My e-mail is:  [email protected]

    0
    #135554

    Nadir Minoo Patel
    Participant

    Hello Paul,
    Enjoyed your simple straight forward methodology. Would appreciate if you can forward that “word” document to me at: [email protected]
    Regards
    nader

    0
    #135565

    Greenstein
    Participant

    Hi Paul,
    Could you send me a copy of your study as well?
    [email protected]
    Thanks
    Jeffrey

    0
    #135575

    Mikel
    Member

    Paul,
    My I have a copy of the Word document as well.
    My email is [email protected]
    Thank you so much.
    Stan

    0
    #135606

    Csaba
    Participant

    Hi Sanjay!
    I totally agrree with Paul’s approximation. The best way is the using of Weibull distribution. Check this link to know more about Weibull’s strategy. It is my favorite software for maintenace issues.
    Csaba
    http://www.weibullnews.com

    0
    #145512

    Fabio Paiva
    Participant

    Paul,
    Thanks for your suggestion.
    It would be of real help if you can send me the word document.My email id is fabio.paivacomau.com.br
    Regards,
    Fábio Paiva

    0
    #166671

    Arvind Sharma
    Participant

    Dear Paul ,
    Greetings and Happy New Year .
    I am new to SS , and a Finance professional working out of India .
    I have been assigned a project on Reducing the Machinery Downtime , which is a perennial problem in our organisation .
    I am trying to learn as much as I can on how to proceed on this project .Seeing your messages on the this issue and replies to various queries , you can help me by downloading your experience on this and guide me along .
    Can you please send me this word document , and any other basic written material you have on this subject .
    I consider you my MBB on this issue !!!!
    Please help
     
     
     

    0
Viewing 20 posts - 1 through 20 (of 20 total)

The forum ‘General’ is closed to new topics and replies.