In SMT production department, tiny devices, like chips, transistors, etc. are mounted on the printed circuit boards using the CMS (Surface Mounting Device) machine. This CMS machine takes inputs (tiny devices) in the form of spools. Reels of the desired material are loaded into the machine and the software does the rest of the work. As the SMD machine needs coil materials, it is necessary to have a separate warehouse other than the raw material warehouse. The cause of this requirement is that the shelves in the raw material warehouse were not suitable for storing this type of sensitive devices and finding the material you need would take a long time because there are a lot of spools to search for. For the reasons mentioned above two more warehouses are built. One is SMD inventory, the other is SMD WIP inventory. These warehouses consisted of storage machines called KARDEX. KARDEX is a machine that could be mounted inside a wall and could store and retrieve material in its trays. The model of KARDEX used in SMD inventory uses a robotic arm to retrieve the required tray, and the model of KARDEX used in SMD WIP inventory uses a chain system to retrieve the required tray. When a work order is opened for parts produced on the SMD machine, the work order form is first sent to SMD inventory, instead of raw material inventory. In SMD Inventory, work order requirements are extracted from KARDEX and sent to SMD WIP Inventory. In other words, the use of SMD inventory is the responsibility of the production planning department. Once the work order requirements have been sent and loaded into the KARDEX in the SMD WIP inventory, the production department retrieves the materials it needs to produce the work order from the SMD WIP inventory. Not all work order requirements need to be recovered at once, partial recoveries are also possible. That is, the use of SMD WIP inventory belongs to the production department, but the responsibility for SMD WIP inventory belongs to the production planning and control department. The material recovery process can be seen in FIGURE PD.1 below:FIGURE PD.1 MATERIAL RECOVERY PROCESSAs the raw materials of the SMD machine are stored in reels, when the work orders arrive in the SMD inventory , materials from multiple work orders can be transferred to SMD WIP inventory in the same reel.