Scrap Types
In an ideal scenario, all scrap is accounted for. However, there are reasons why this is not always the case, including:
- Time latency means you cannot count everything until the job is stopped
- Buffer stock can mean that material does not flow through the line in the same sequence
- Quality samples can be taken off the production line
- Material can be removed from the line for other reasons
Accounted Scrap
Accounted Scrap has a defined record that identifies the scrap event. An operator can record accounted scrap, or a device can record scrap through an OPC counter. For example, a vision system can automatically reject material within the production line.
Unaccounted Scrap
Unaccounted Scrap is calculated from the difference between the input and output quantities in a production line.
If there is a discrepancy between the input and output counts, then material must have been lost in the process.
- Total scrap = Quantity In - Quantity Out
- Unaccounted scrap = Quantity In - Quantity Out - Accounted Scrap
For example, if 100 pieces are counted into the production line and only 90 pieces exit, the total scrap is 10 pieces. If 8 pieces of scrap have been recorded during production, then:
- Accounted Scrap = 8 pieces
- Unaccounted Scrap = 2 pieces