Question 1

What is the difference between MTBF and MTTF?

Accepted Answer

MTBF applies to repairable systems — it measures the time between failures, assuming the system is restored after each failure. MTTF (Mean Time To Failure) applies to non-repairable items — it measures the expected time until the first (and only) failure. For example, a light bulb has MTTF; a manufacturing robot has MTBF.

Question 2

How can I improve equipment availability?

Accepted Answer

There are two levers: increase MTBF (improve reliability through better components, derating, environmental control, and design redundancy) or decrease MTTR (improve maintainability through modular design, diagnostic tools, trained technicians, and spare parts availability). Typically, reducing MTTR delivers faster ROI than improving MTBF.