The machine/job shop has several machines for milling, grinding, welding, stamping, etc. The materials are milled, and may then travel to the grinding machine, and next to the welding machine. The ERP Package for discrete manufacturing has a Material Requirements Planning (MRP) module that includes a routing. In a route, a machine is a workcenter, that my have several operations. In the Acumatica ERP package each operation has its materials, labor, machine, tools and maybe administrative overhead. The quantities and cost of all this is planned ahead during a run of the MRP that uses a Bill of Material (BOM). Once the MRP has been run, and the ordered materials have arrived, the planned work/production order is released to start the actual production. As the materials, labor, machine capacity and tools are consumed at each operation, actual consumed quantities and cost are captured and calculated. Also the Work in Progress (WIP) is captured and stored.
The quantity of the finished product is captured and stored in the database in order to determine the shipment quantity. It is possible that your company never stores the finished product in your warehouse but the quantity is still needed in the General Ledger to create the correct invoice.
The generic machine shop flow (make to order, engineer to order, ..) will be shown in the Acumatica video below. You can click on the full screen size button at the bottom left of the video to see it full screen.