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Gents,

I have question regarding to MTBF.if equipment has several breakdown some related to ( Maintenance or operation & other departments) & I want to calculate MTBF due maintenance issue as a maintenance  KPI .. is that will be ok ?? 

 

also if i calculate weekly MTBF for equipment.& i have only one failure.how do i calculate it??

Thank you

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Hi @Gladiator, theoretically you could of course only include failures that related to maintenance in an MTBF calculation, but I would not recommend it for a few reasons:

  • most failures have multiple causes and you will likely find that you have failures where maintenance contributed to the failure but might not have been the immediate 'trigger'. I feel you could waste a lot of time debating which failure to include or not
  • using a jointly owned metric like MTBF, or uptime, can be very useful to build collaboration between departments because they are now all working to a joint goal i.e. to increase MTBF or uptime
  • separating your KPI like this may lead to maintenance not getting involved in equipment that has a low MTBF just not due to maintenance issues. Imagine you have a category of equipment that has a lot of design issues and therefore experiences a low MTBF. That low MTBF would be owned by engineering given that it's due to design, but who has to make the frequent repairs? Maintenance and so it should be of great interest to you to reduce those defects and stop the recurrent repairs, but the way the MTBF metric is being used it may just lead to "well thats an engineering problem" ...

Please do let us know which way you go with this.

 

PS. Would you mind changing your name to your real name at least your first name? I really prefer to keep this forum as supportive and friendly as possible and addressing each other by our names is always helpful in that. Thank you for your understanding.

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Hello Eric,

Thank you for your answer regarding to the MTBF. i will put my KPI on the equipment as general instead of the department to improve the equipment.

I'm looking for this answers below.

1-  if im trying to calculate Weekly MTBF for an equipment. for example  :the equipment should be run 24/7 .so total hours is 168 hr per week as but we have just one break down failure ( 2 hours ) for example. how can i calculate the MTBF if i just have one failure

2-For overall equipment effectiveness .as it equal =Availability X performance rate X  quality rate .

quality rate % is :total produced unit-defective produced unit/ total produced unit  %

if i have grinding mill ,crusher,pumps or etc .. what is the defected unit .i mean i would put the quality rate as 100% am i correct ?

3-I'm looking to build reliability data based  what would you advise me to improve the reliability ? as we are right now have condition monitoring ,RCA ,defect elimination

finally i don't have an option to change gladiator name :i tried to go to the settings.but there is no option change .

Thank you for your help

appreciated

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Hi @Gladiator, some quick answers:

1. if you experience 1 failure in 168 operating hours then the MTBF is 168 (168/1) and your equipment uptime is 98.8% (168-2/168). MTBF is not very useful to calculate on a weekly basis in my view, better opting for uptime if you want a weekly metric.

2. indeed OEE = Availability x Performance x Quality which useful in a manufacturing environment where your production line can suffer from availability losses, performance (capacity) losses and quality losses. If your production line does not have a rejection rate i.e. you never produce underspec product then your quality would indeed be 100%. If your production line can not slow down and experience a loss in capacity, i.e. it either runs at 100% of capacity or it does not run then the performance factor is not relevant. So if both quality and performance are not relevant to your operation then you're basically just using Availability. 

3. I can't really make any sensible recommendations on how to improve reliability in your plant, without knowing a lot more. What I would suggest you do is to log all your downtime carefully, determine whether it is scheduled downtime due to PM's or unscheduled (reliability issues). For all unscheduled downtime assign a category and cause. Analyse the data and see where your downtime is coming from, then start tackling that issue.

PS if you let me know what name you'd like to use I can update it for you in the back-ned of the community software

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