How to correct scrap quantities when by mistake the quantity is reported wrong at the first time.

Let us consider a sample route containing Step1 to Step 10.

When an SFC: SFC_1 with 250 PCS has an NC of type Scrap reported first time manually at Step6, then the left over quantity on SFC_1 is 240 PCS.

The completed Quantity on SFC_1 from Step6 until Step10 will be 240 PCS and assume that the SFC is currently in process at Step9

At Step9, if the operator recognizes if the Scrap Quantity at Step6 is 20 PCS instead of 10 PCS (by mistake user didn’t report the other 10 PCS), then what are the various possible ways to correct the Scrap Quantity in order to have the right Yield and NC Log data at the subsequent operations.

If we choose to perform a SFC Step status on SFC_1 for 10 quantity from Step9 to Step6, then you can have 10 PCS available at Step6 and a NC of type scrap can be registered so that the NC log looks accurate.

But with this the Yield by Operation which is based on the completed quantity at an operation goes wrong, because the Step6 has 230 PCS completed, whereas, the intermediate operations Step7, Step8 has 240 PCS completed.

So how can we correct the Scrap Quantity (From Low to High) without affecting the Yield By Operation calculations ?

Thanks,

Henri