OEE Academy button
10. How do we treat a coil change at a slitting machine?

Q: We are slitting coils into steel bands. How should the time needed to change coils be integrated into the cycle time of the slitting machine?

oee of a slitting machineSituation: A large coil of steel-foil is placed in the slitting machine. The steel-foil is un-winded and slitted in several steel bands. At the end of the coil a new coil must be placed in the machine and the process goes on.

Arno Koch • The goal of OEE is to visualize ALL losses. When the machine is not slitting although there would be a demand, this is a loss. Even if (you think) you cannot avoid it. This loss can be visualized in two manners:

  • As waiting-time in the availability or
  • as a performance loss (it would be considered to be a minor stop).

Make losses visible!

When the changeover time would be settled in a (reduced) cycle time, the loss would not become visible, and probably changeover time reduction will hardly become a subject of improvement activities.

As a rule of thumb, usually a waiting time larger than 1 to 5 minutes is to be considered as an availability loss. Since a coil-change normally takes longer than a minute, I would suggest to register this as ‘coil changeover time’ and visualize it in the category ‘waiting time’. (Meaning: The machine is waiting until the coil is being changed). In that way it is possible to see how many times we change a coil and how many minutes of potential production time is being lost. By applying SMED or eventually modifying the equipment, this loss might be minimized.

Cycle time slitting machine – Conclusion:

The cycle time of the slitting machine should be base on slitting and slitting alone. This is it’s sole purpose!

Answer still not found?

If you checked all the sections in the Academy, yet still not found the answer to your question, ask it here.
To help you best, please be as specific as possible and please understand:
We do not want to reply to anonymous questions.