List last month's scrap by mold from the ERP, the plant's job and stock system, and by shift where it is recorded.
At the start of a shift, empty the scrap bins at the three molds highest on the list that are running, and at one other press.
At the end of that shift, weigh the rejected parts in each bin on the floor scale.
Note whether the fault sits in the same place on every part.
Cost
About $160 of a process technician's time: about three hours, at $52 per hour. The list comes from the ERP and the bins go on the floor scale the plant has, so nothing is bought.
Duration
About an hour for the list, then one shift for the bins
Confirmed if
A few molds lead the list, and the rejected parts in their bins weigh several times what the other bin holds. Settings are the likely cause if their scrap differs from shift to shift, or the faults change from part to part.
Ruled out if
Last month's scrap is spread across many molds, and the three bins hold about what the other bin does.
The settings are also ruled out as the cause if the rejected parts carry the same mark in the same place on every shift.