August 21, 2012
OEE is a powerful tool that helps improve productivity in industry. There are several systems that help to calculate the level of productivity. I have therefore tried to classify the various schemes into different levels based on their complexity.
Level 1. An off-line system based on historic data with a low level of detail. This sort of system is created in Excel, or similar, format. The aim is to get an idea of the current situation to estimate the potential for improvement. Typical comments after having evaluated production with a level 1 system are:
- Oops, we're only getting 50% of the equipment's theoretical capacity!
Level 2. An off-line system based on information that is entered by the operators. A level two system uses relatively simple systems with fields for input, a database and a report management function. The purpose of such a system is to produce information about the major losses. A typical comment after having begun work on a level two system is:
- Look at that! Maintenance-related problems accounted for only 7% of downtime while change-overs represent 24% material and shortages 31%!
Level 3. An on-line system linked to specific equipment. With an on-line system connected to the equipment's PLC system, it is possible to get exact information about downtime that increases the credibility in the data produced. Just like level 2 systems, with a level 3 system the operator will need to classify the reason for the break since the equipment usually does not know whether it has stopped for a coffee break or because of a lack of orders. With a level 3 system, we can conduct analyses such as
- The machine stopped 478 times last week. The feeder stopped 14 times. What can we do to improve this situation?
Level 4. Production monitoring systems for an entire facility. To achieve this requires parent data processing such as MES (Manufacturing Execution System), often complemented with a business intelligence solution to create reports. With a level 4 solution, we can get a real-time overview of the entire facility. The type of questions raised in a level 4 situation are:
- Line 8 has run at only 50% OEE the last hour, do we risk missing some deliveries?
Starting to work with OEE is a learning experience for the entire organisation and, to be effective, the implementation must be accompanied by a strategy to decide how this new information will be used. The level of system you choose depends therefore mainly on the level of maturity and the drive for constant improvement that prevails in the organisation.
By Oskar Olofsson