Calculation of Activity Scrap
(PPM)
Use
In the production
process model plan (PPM plan), for a product produced in-house, you can
specify in detail for each activity how much scrap is produced in this
activity. If an activity produces
scrap, the activity must process a larger quantity of the order product to
achieve the required yield. The
activity therefore consumes more components. In the case of quantity-dependent processing times
and quantity-dependent resource consumption, the
net duration and
the
resource
consumption of the activity are increased. The system corrects the quantity during the PPM
explosion. It calculates the total quantity of an activity to be produced
during the plan explosion according to the following formula:
Total Quantity = Yield x 100 % / (100 % - Scrap in %)
You can choose for each activity whether the yield to be produced from the activity is:
· The procurement quantity of the order
· The total quantity required by the successor activity
This case is relevant if the successor activity also produces scrap. The predecessor activity must therefore produce a yield that corresponds to the total quantity required by the successor activity. A scrap-related quantity increase is therefore passed on to the successor activity.
Prerequisites
· To allow the system to take account of activity scrap during an activity, scrap must be specified as a percentage in the plan of the PPM for the activity.
· To allow a scrap-related quantity increase for an activity to be forwarded to a successor activity, the Material Flow indicator must be set for the relationship between these activities.
Example
Scrap without material flow
An order comprises three successive operations each consisting of one processing activity. You have not set the Material Flow indicator for the relationships between activity 1 and activity 2, and between activity 2 and activity 3. This means that you want the activity quantities to be calculated individually for each activity based on the order quantity. You have entered the following scrap data for the activities:
· Scrap for activity 1: 5%
· Scrap for activity 2: 7%
· Scrap for activity 3: 5.5%
The procurement quantity of the order is 100 pieces. Using this data, the system calculates the quantities to be processed by the activities:
· Quantity for activity 3: 100 pieces / 0.945 = 106 pieces
· Quantity for activity 2: 100 pieces / 0.930 = 108 pieces
· Quantity for activity 1: 100 pieces / 0.950 = 105 pieces
If each of the activities requires a component, these have to be provided according to the activity quantities – for example, 105 pieces for activity 1, 108 pieces for activity 2, and 106 pieces for activity 3.
Scrap with material flow
As in the example above, an order comprises three successive operations that each consist of one processing activity. You have set the Material Flow indicator for the relationships between activity 1 and activity 2, and between activity 2 and activity 3. This means that you want the quantity to be processed in an activity to be provided by the predecessor activity as yield. You have maintained the following scrap data in the PPM plan for the activities:
· Scrap for activity 1: 5%
· Scrap for activity 2: 7%
· Scrap for activity 3: 5.5%
The procurement quantity of the order is 100 pieces. Using this data, the system calculates the quantities to be processed by the activities:
· Quantity for activity 3: 100 pieces / 0.945 = 106 pieces
· Quantity for activity 2: 106 pieces / 0.930 = 114 pieces
· Quantity for activity 1: 114 pieces / 0.950 = 120 pieces
For the order to deliver 100 pieces, the first activity must process 120 pieces, the second 114 pieces, and the third 106 pieces. The components required by the activities must be provided according to the activity quantities – for example, 120 pieces for activity 1, 114 pieces for activity 2, and 106 pieces for activity 3.
Combination of assembly scrap and activity scrap
See Scrap Calculation (PPM, R/3 RTO)