TPM-OEE MTBF MTBA MTBR MTBO
MTBA - Mean Time Between Assists
--------------------------------------------------------------------------------
The average time the equipment performed its intended function between assists; productive time divided by the number of assists during that time. Only productive time is included in this calculation.
Mean Time Between Assists (MTBA) = Productive Time/ Number of Assists
MTBF - Mean Time Between Failures
--------------------------------------------------------------------------------
The average time the equipment performed its intended function between failures.
Definition -> Productive time divided by the number of failures during that time. Only productive time is included in this calculation.
Mean Time Between Failures (MTBF) = Productive Time/ Number of Failures MTBO - Mean Time Between Offline
--------------------------------------------------------------------------------
The average time to maintain the equipment in or return the equipment to a condition where it can perform its intended function when downtime incurred.
Definition -> The sum of all downtime (scheduled and unscheduled) during a specified time period, divided by the number of downtime incidents during that period.
Mean Time Between Offline (MTBO) = Downtime/ Number of Interrupts
MTTR - Mean Time To Repair
--------------------------------------------------------------------------------
The average time to correct a failure and return the equipment to a condition where it can perform its intended function.
Definition -> The sum of all repair time incurred during a specified time period (including equipment and process test time, but not including maintenance delay), divided by the number of failures during that period.
Mean Time To Repair (MTTR) = Repair Time/ Number of Failures
OEE - Definition
--------------------------------------------------------------------------------
Stack Chart of Productivity Losses and Improvement Domains:
OEE - Overall Equipment Efficiency
Definition : The fraction of total time that equipment is producing effective units at theoretically efficient relates.
OEE = Theoretical Production Time for Effective Units/ Total Time
OEE = Availability Efficiency X Performance Efficiency X Quality Efficiency
Availability Efficiency
Definition : The fraction of total time that the equipment is in a condition to perform its intended function.
Availability Efficiency = Equipment Uptime/ Total Time
Performance Efficiency
Definition : The fraction of equipment uptime that the equipment is processing actual units at theoretically efficient rates.
Performance Efficiency = Theoretical Production Time for actual Units X Production Time
Operational Efficiency
Definition : The fraction of equipment uptime that the equipment is processing actual units. Operational Efficiency = Production Time/ Equipment Uptime
Rate Efficiency
Definition : The fraction of production time that equipment is processing actual units at theoretically efficient rates.
Rate Efficiency = Theoretical Production Time for Actual Units/ Production Time
Theoretical Production Time
(for Actual Units or for Effective Units)
Definition : Production time (for actual units or for effective units) during a period of observation that is earned at strictly theoretically efficient rates and assumes no efficiency losses.
Theoretical Prod. Time = Σi (Actual Units of Recipe I x THTi)
= ΣI (Effective Units of Recipe I x THTI)
(where THTI = theoretical production time per unit of recipe)
Theoretical Production Time
(for Actual Units or for Effective Units)
Definition : Theoretical Production Time (for actual units or for effective units) may be calculated in terms of theoretical unit throughput by recipe.
Theoretical Prod. Time = Σi (Actual Units of Recipe i)/ UPHi
= Σi (Effective Units of Recipe i)/ UPHi
(where UPHi = theoretical unit throughput by recipe of recipe i)
Quality Efficiency
Definition : The theoretical production time for Effective Units divided by the theoretical production time for Actual Units.
Quality Efficiency = Theoretical Production Time for Effective Units/ Theoretical Production Time for Actual Units