What is Rate Loss? (Explaination)

Rate Loss Explanation

What affects Rate Loss

Rate Loss is what is left over. The system takes the time the line was available to run, works out how much output that time should have given at the target rate and compares it to the counted output. Anything missing becomes Rate Loss.

3 things moves Rate Loss up or down

1. The production count
If the count is lower than what the line really made, Rate Loss goes up.

Common reasons:

• Product was rejected and never counted.
• The line ran slowly for a few minutes after a restart or a changeover.
• The count is in a different unit than the target rate, for example cases instead of bottles.
• Order length: 480 minutes
• Recorded downtime (Rate loss): 60 minutes
• Running time: 480 - 60 = 420 minutes
• Expected output at the target rate: 420 x 25 = 10,500 units
• Counted output: 9,000 units. At 25 per minute that is 360 minutes of production.

2. The recorded downtime
If a stop\downtime is not recorded or is recorded as shorter than it really was, Rate Loss goes up.

Time that is not booked as downtime stays in the running time. The system then expects output for that time. There is no output, so the missing output becomes Rate Loss.

This is why a line with many small stops that are not recorded can show a high Rate Loss and very little downtime.

3. The target rate
If the count and the downtime are both correct and Rate Loss is still high, the target rate for that product may be higher than the line can reach. An administrator can review it under OEE Rates in Maintmaster OEE Manager.

Example, If no stop\Downtime is recorded

One order, 8 hours long. The target rate for the product is 25 units per minute.

The order as it should be

Rate Loss: 420 - 360 = 60 minutes, which is 1,500 units.

Now change one input at a time

What the example shows

When the 30 minute stop\downtime is not recorded, the total loss on the order is exactly the same, 120 minutes. Only the split changes. In the first row it is 60 minutes of downtime plus 60 minutes of Rate Loss. In the second row it is 30 minutes of downtime plus 90 minutes of Rate Loss. The missing 30 minutes did not disappear. It moved into Rate Loss where there is no reason code and nothing to act on.

When the 500 rejected units are not counted, they are worth 20 minutes at the target rate, so Rate Loss grows from 60 to 80 minutes. If those units are counted as rejects, the same 20 minutes is reported as quality loss instead.

In short: Rate Loss is the part of the loss that nothing else has explained yet. Record the stops and count the units and it shrinks to the real speed loss.

FAQ

• Why is my Rate Loss so high?
  Start with the two inputs. Check the production count on the order against what the line really made and check that every stop is recorded with the right duration. A count that is too low or downtime that is missing will both push Rate Loss up. If both are correct, the target rate for that product is the next thing to review.

• A stop shows as Rate Loss instead of downtime. Why?
  If the order is still running, wait. A stop can show as Rate Loss until it ends and gets a reason, then it moves to downtime. Always check on the completed order first.

  If the stop is not recorded at all, the time stays in the running time and becomes Rate Loss instead. Very short stops may also be too short to be recorded on your line. Contact Maintmaster support with the line, the order and the time of the stop, and we can check the settings with you. Also see How Min Downtime and Reassign Time work together

• The line ran at full speed, so why do I have Rate Loss?
  Then the counted output is probably lower than the real output. The most common cause is product that was rejected and never counted. Another cause is a count in a different unit than the target rate.
  
  Open Order Detail for the run and look at the Production Timeline. If the counts are lower than what your operators saw on the line, the count is the problem, not the calculation.

• We always get Rate Loss just after a restart. Is that a fault?
  No. The line needs a short time to reach full speed and during those minutes the real output is below the target rate. That is a genuine performance loss so it is recorded as Rate Loss. Fewer stops means less of this loss. If product is ejected during the restart, counting those rejects moves that part into quality loss instead.

• How do we get less Rate Loss and more real downtime reasons?
  Record the stops. When a stop is recorded and given a reason, that time is reported as downtime under your reason code instead of sitting inside Rate Loss. Very short stops are grouped together as Short Stops, which is reported under Performance.
  
  If stops on your line are not being recorded at all, contact Maintmaster support and we can review the stop settings for your site with you.

• Will this change our old orders?
  It depends on the setting.
  
  For target rates, yes. A new OEE rate applies from the next order onwards, and an administrator can also use Backdate OEE rate in Maintmaster OEE Manager to apply the new rate to a period that has already been produced. Those orders are then recalculated. Take a copy of the figures first, because the old rates are overwritten and cannot be put back. See How do I backdate the OEE rate?
  
  For other settings, no. Changes such as Min Downtime, or changes to how automatic downtimes are raised, only apply going forward and history cannot be changed. If you need historical orders looked at, contact Maintmaster support.