MTTR | Mean Time To Repair | MTBF | Mean Time Between Failure | MTTF | Mean Time To Failure
What is MTTR, MTTF & MTBF?
👉 With the help of MTTR, MTTF and MTBF we know about Availability of machine or System.
👉 (MTBF) Mean Time Between Failure and (MTTR) Mean Time To Repair are two important KPI's in Plant maintenance mangement and lean manufacturing.
MTTF:
“Mean time to failure” is the average time that a machine will function before it fails. It is the mean lifetime of the machine.
MTBF:
“Mean time between failure” is a metric that concerns the average time elapsed between one failure to next failure.
It’s calculated by a formula;
MTBF = (Total available time - Total breakdown time) / Number of breakdown
or
MTBF = MTTF + MTTR
How to improve MTBF:
👉 Through regular maintenance of machine.
👉 By implementing small Kaizen activity for the machine.
👉 Make a machine failure history book and take a strong preventive action on its so this failure will not repeat in future.
Benefits of MTBF:
How to improve MTBF:
👉 Through regular maintenance of machine.
👉 By implementing small Kaizen activity for the machine.
👉 Make a machine failure history book and take a strong preventive action on its so this failure will not repeat in future.
Benefits of MTBF:
👉 It is the basic indicator to predict the reliability of a machine.
👉 The MTBF increase will show that your maintenance methods are going good.
Example of MTBF:
 |
| This table is taken for an example, its data is taken on a random base to understand you. MTBF = (Total available time - Total breakdown time) / Number of breakdown MTBF = (92.5 - 3.5) / 5 MTBF = 17.8 Hours Note: ⇒ It's value should be maximum always. ⇒ This index reveals that a failure in a machine occurs every 17.8 Hours. |
MTTR:
"Mean Time To Repair" is the average time that it takes to repair something after a failure. This includes notification time, analysis time, waiting time, reassembly time and testing time etc.
It’s calculated by a formula;
MTTR = Total breakdown time / Number of breakdown
Why MTTR is important:
👉 Long MTTR means loss of productivity and loss of organization's profit.
👉 Due to long MTTR sometimes, a company can miss orders or it can impact on business relationships.
👉 To reduce the impact of MTTR, organizations should have their own maintenance teams and hold critical spare parts onsite or run parallel production lines.
How to improve MTTR:
👉 We can improve MTTR by team work.
👉 Implement and follow the breakdown history concept.
👉 By providing training on quick repair and motivate people.
👉 maintaining 5S at our workplace.
👉 Keep critical spare parts in stock.
👉 Follow the SOP's (standardize operation procedure).
Benefits of MTTR:
👉 It indicates the efficiency and productivity of a machine.
👉 it reduces losses in profit.
👉 It improves productivity and quality of the product.
👉 By reducing MTTR we can improve the efficiency and productivity of a machine.
Example of MTTR:
MTTR = Total breakdown time / Number of breakdown
MTTR = 3.5 / 5
MTTR = 0.7 Hours (42 minutes)
Note:
⇒ It's value should be near to Zero always.
⇒ The Company knows that every 17.8 Hours (MTBF), the machine will be unavailable for 42 minutes (MTTR)
Availability:
👉 It is the ratio of the time a machine is functional to total time required.
👉 Higher the availability, Higher the operational time and Higher the accessibility.
Formula:
Availability = MTBF / (MTBF + MTTR) X 100
Availability = 17.8 / (17.8 + 0.7) X 100
Availability = 96.21%
Note:
