We were speaking to a prospective client recently and the issue of the need for a frozen production zone was raised.

The company produces many finished SKU’s from a limited number of inputs and can easily change production mix and sequences if these changes support improved customer service objectives.

Their environment is flexible enough to allow them to change schedules prior to the start of a shift. Experience leads us to believe that the capability to change the schedule on a daily basis would be sufficient for their needs.

It transpired that they wanted a frozen zone so that they could measure production achievements against the plan on a weekly basis.

We always wonder about the value of this measurement. Who is going to be measured and how fair will the measurement be?

Examples of issues that might arise are:

  1. Impact of downtime
    • The machinery experiences downtime at the start of the week e.g. load shedding occurs.
    • All schedules are pushed out by the downtime.
    • Is the foremen and / or operator team of the shift affected, measured against expected output prior to downtime occurring?
  2. A required input is rejected.
    • The resource / line needs to be restarted.
    • All schedules are pulled forward by the product removed from production.
    • Is the foremen and / or operator team of the shift affected, measured against expected output prior to downtime occurring?
  3. Etc

Far more meaningful would be to:

  1. take a snap-shop at the start of the week in terms of expected volumes to be achieved and then measure these at the end of the week.
    • Doing this enables the factory to be measured against volume of output produced vs. required irrespective of the mix delivered.
  2. Measure the sequence of actual production vs. the schedule to ensure that the factory meets the sequence require by the scheduler.
    • This ensures that the plant is producing in the sequence necessary to support customer service objectives.
  3. Measure the OEE of key equipment to ensure that key resources are being used efficiently.
  4. Measure the unplanned overtime required to meet the weekly schedule.

Companies that talk about frozen zones are frequently using concepts learned when running more manual systems. One needs to evaluate manufacturing concepts to ensure that these have not been made obsolete in the new digital world.

What do you think of having a frozen zone?