What is World Class OEE ?
This blog is written by Dasarathi GV, Director-Applications, Cadem Technologies Pvt. Ltd.
Cadem makes software products for:
1. Cycle time reduction, CNC programming for CNC turning and milling
2. CNC machine monitoring and DNC
3. CNC skill development and education.
CNC
What is World Class OEE ?
It is generally thought that world class OEE is 85 %. Where does this number come from ?
Seiichi Nakajima, the orginator of OEE (and TPM, and the six big losses), thought up this number
30 years ago, way back in 1984. It is based on Availability, Performance and Quality numbers of 90 %, 95 % and 99 % respectively.
OEE = Availability × Performance × Quality = = 0.9 x 0.95 x 0.99 = 0.85
This number was coined for the automotive industry, that is characterized by mass production of a single part running continuously with a set process. On a job shop with high part variety of
parts and frequent setup changes it may be impossible to achieve. If your A,P and Q are 0.7,
0.9 and 0.95 (typical numbers on a job shop), the OEE drops to 0.6. On a lot of shop floors (like those doing one-off parts) it can be as low as 40 %.
The way to use the OEE number is to just track and improve it in incremental steps, NOT to set an impossibly high target and try to achieve it. The latter can be disheartening for personnel on the shop floor, and lead to fudging of numbers just to show a high number.
Speaking of fudging numbers, some time ago we in Cadem came across a company that had achieved ‘world class OEE’ by excluding the setup and inspection times from the downtime. This gave them artificially inflated values of Availability, and they had no incentive to improve their
processes to reduce the setup and inspection times. They were interested in implementing our
LEANworks productivity tracking system, and wanted the OEE formula in the software to be
customized to their requirement. The deal never went through because (predictably) they said they did not need to track or improve their OEE since they had achieved ‘world class’ already.
Action point
Aim for continuous incremental IMPROVEMENT in OEE, rather than trying to achieve a FIXED number.
Etc.
Ever heard passengers celebrating a train’s birthday ?
The Deccan Queen that runs between Pune and Mumbai’s CST station (192 km., 3.25 hrs.), is now 86 years old (born 1930). Its birthday is celebrated every year by its passengers, on June 1. The train leaves at Pune around 7 AM and reaches Mumbai around 10:30, leaves Mumbai around 5 PM and reaches Pune around 8:30.
The reason that the Queen’s passengers love it so much is that many of them spend much of their life on it. There are people who live in Pune, work in Mumbai, and travel up and down every day. They travel almost 400 km., and spend 7 hours on the train, every day, for years together.
They have season tickets, and there are 4 whole compartments reserved for these regulars. They meet each other every day, know each other well, play cards on the train, make plans for the weekend together, celebrate birthdays, promotions. The train is a match maker too – people have met on the train and got married. I travelled on the train recently, and heard of someone who had spent 35 years commuting to work on it, and stopped only because he retired from his job.
The Deccan Queen is the only train in India with a diner (a dining car). The regulars are known
to the waiters, and when they go to the diner they don’t even have to order – the waiters know
exactly what they want, and get it.
This train definitely deserves its birthday celebrations.