If a work center is a subcontracting work center, you can enter a lead time in work days for orders on the work center. Here you can enter how many days prior to the shipment of goods to the subcontractor you must send the corresponding purchase order.
The date when the purchase order must be sent is called Order period operation. When the manufacturing order is registered and replanned you can enter how many days before the subcontract's start period this period shall be. You can see the date that is set on the manufacturing operation in the Order Info, Adding / replanning and Order List - Subcontract procedures. You can also select by this date in the Order List - Subcontract and Comprehensive Document (Subcontract).