The mean repair time (MTTR) refers to the time it takes to repair the system. The meaning of repair time generally indicates the efficiency of the correction process and the expected time span from failure to recovery. The time after the failure indicates the reliability of your system and means that the recovery time is the average time it takes to recover from a failure, i.e. how long it takes for your systems to be back up and running
Ideally the lesser the time the better the productivity and the higher yield can be achieved
The Mean Time Between Failure or MTBF represents the time interval between one breakdown and the other in the same machine.
The MTBF has to be higher for well maintained machines.
MTBF=Total Operational Hours/No of Breakdowns
OEE- Overall Equipment Effectiveness is the measure of how well the Equipment Production,Quality of Product and Machine’s Performance has fared.
Availability refers to the total available time for doing production.
Availability=Running time/Available Time
The Quality portion of the OEE Metric represents the Good Units produced as a percentage of the Total Units Started. The Quality Metric is a pure measurement of Process Yield that is designed to exclude the effects of Availability and Performance. The losses due to defects and rework are called quality losses and quality stops. Reworked units which have been corrected are only measured as unscheduled downtime while units being scrapped can affect both operation time and unit count.
Calculation: Quality = (Units produced – defective units) / (Units produced
Also known as “process rate”, the Performance portion of the OEE Metric represents the speed at which the Work Center runs as a percentage of its designed speed. The Performance Metric is a pure measurement of speed that is designed to exclude the effects of Quality and Availability. The losses due to wasted performance are also often called speed losses. In practice it is often difficult to determine speed losses, and a common approach is to merely assign the remaining unknown losses as speed losses.
Calculation: Performance = (Parts Produced * Ideal Cycle Time) / Operating time
First Pass Yield
First pass yield denotes the number of products produced with good quality in first time without the need of Rework,Scrap.
The Higher the First pass yield the higher the quality of the product.The digital work Instruction helps the operator in improving the same.
First Pass Yield= Quality Units / Total Units Produced
Health & Safety Incident Rate
Incidence rates can be used to show the relative level of injuries and illnesses among different industries, firms, or operations within a single firm. Because a common base and a specific period of time are involved, these rates can help determine both problem areas and progress in preventing work-related injuries and illnesses. An incidence rate of injuries and illnesses may be computed from the following formula:
(Number of injuries and illnesses X 200,000) / Employee hours worked = Incidence rate.
The 200,000 figure in the formula represents the number of hours 100 employees working 40 hours per week, 50 weeks per year would work, and provides the standard base for calculating incidence rate for an entire year.