 Usually the first approach (scanning at the withdrawal) is used for materials which are piece goods.If the materials are not piece goods (bulk material, yard ware), then the workplace has to report the consumed quantities after it has finished its job on a particular production order.If a process control system is being used then the process control system will report the consumed materials directly to the ERP\MRP- System or to the MES and then the MES reports to the ERP.