Mttr Mtbf Calculation.pdf 2nc68

MTTR /MTBF Calculation

MTTR Concept and Calculation MTBR, MTBF and MTTR are tools to measure effectiveness of Maintenance task performed. As we all aware that equipment downtime has direct impact on bottom line of any company so it becomes very important to track and analyse MTBR,MTBF and MTTR. It is used to find out reasons behind the short and long time break down duration. Recording of breakdown Organization uses different ways to record breakdowns in SAP Plant Maintenance module, i.e. By separate Order type for breakdown, by breakdown tick on input screen of notification. It is measure duration between malfunction start and malfunction end date and time, if we add tick breakdown check box in Notification then system default takes system date and time as malfunction Start time and Date while Malfunction end records at the time of order closure. MTTR can be calculated from history details of breakdowns. MTTR Calculation

First Breakdown 40 hrs Second Breakdown 30 No of Breakdowns 02

so final calculation of MTTR will be MTTR= ((40+30)/2)) MTTR = 35 Hrs.

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MTTR /MTBF Calculation

MTBR/MTBF: - Mean Time between Repair MTBR represents average duration between breakdowns. MTBR is very important factor to know status of equipment health. Here we have taken example of Gear motor for calculation purpose. MTBF model assumes the failed system is immediately repaired. In SAP there are few reports available for monitoring MTTR, MTBF and MTBR. Two cases have been depicted here. Case1: No. Of Failures = 6 (Denominator for MTTR, MTBR Calculations) Total Uptime = U1 + U2 +U3 + U4 + U5 + U6 + U7. = 900 Hrs. Total Downtime = D1 + D2 + D3 + D4 + D5 + D6.

= 108 Hrs.

We know that MTTR (Mean Time to Repair in Hrs) = ( D1 + D2 + D3 + D4 + D5 + D6 ) / 6 = 18 . Similarly MTBR (Mean Time Between Repairs in Hrs) = ( U1 + U2 +U3 + U4 + U5 + U6 + U7 ) / 6 = 150 Now, Equipment Availability (%) is: uptime / Total Time = (900 / 1008) * 100 = 89.2 Another formula for Equipment Availability in practice is [MTBR / (MTTR + MTBR)] * 100 = (150 / 168 )*100 = 89.2 Case2: No. Of Failures = 2 (Denominator for MTTR, MTBR Calculations) Suppose here too we get the same total values like: Total Uptime = U1 + U2 +U3 = 900 Hrs Total Downtime = D1 + D2 = 108 Hrs

MTTR (H) = ( D1 + D2) / 2 = 54 . MTBR (H) = ( U1 + U2 + U3) / 2 = 450 .

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MTTR /MTBF Calculation Equipment Availability (%) is: Uptime / Total Time = (900 / 1008) * 100 = 89.2

Failure Rate :- No. Of Failure / Total Time

Case

Duration Downtime Failures (H) (H)

Availability (%)

MTBR (H)

Failure Rate (ʎ)

1

1008

6

108

89.2

150

0.00595

2

1008

2

108

89.2

450

0.00198

MCJB- This report is used for MTTR and MTBR calculation.

Logic of MCJB report is purely based on Breakdown, if Breakdown check box marked as ticked then only system will consider notifications as breakdown notification else it will consider as normal notification. If breakdown notification gets converted into breakdown maintenance order for Material issue or operation confirmation purpose then additional care should be taken at the time of maintenance order closure. At the time of maintenance order completion maintenance notification should also complete in background. We can also get trends of breakdown details in above reports by doing drill down.

TCODE –MCJB This helps to make report according to Equipment. ENTER Equipment Number. Then Execute.

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MTTR /MTBF Calculation

Use T Code - MCI7

PUT MONTH & YEAR THEN EXECUTE.

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MTTR /MTBF Calculation

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