We live in a material world
Manufacturing lives in a material world. It is not surprising that manufacturing systems have a requirement to identify and track materials, because the main purpose of manufacturing is to convert materials in one form into materials of another form. An important part of integrating manufacturing systems with other corporate systems is maintaining and exchanging material identification and information.
The source of the material identification usually resides in an enterprise resource planning (ERP) system, but material information is required in manufacturing operational management (MOM) systems such as manufacturing execution systems (MES), batch management systems, tracking and tracing systems (bar-code scanners and radio frequency identification, RFID, readers), Laboratory Information Management Systems (LIMS), and warehouse management systems. The ERP contains the material masters, the information that is used to identify types of materials and vendors, as well as the information used in inventory, accounting, ordering, receiving, and shipping.
Shared material information between the ERP and MOM can be divided into three main categories: Material class information identifies materials without regard to who supplies the material. Material class identification is used in BOMs (bills of material), recipes, and assembly instructions. Actual material is represented by material lot information . Example material classes could be Magnesium Stearate, 2 inch #8 brass screws, and 50mil Aluminum sheeting. A BOM may specify that 200 kg of Magnesium Stearate is required, but will not normally define the material by source. Material classes contain non-vendor specific nominal values for material properties, such as weight or color.
Material definition information identifies material from specific vendors or sources. For example, material definitions may be Magnesium Stearate from Alpha Chemical identified as MS-0023AC, Magnesium Stearate from Beta Chemical identified as MS-0023BC, and locally produced Magnesium Stearate as MS-0023XX. The material definition is used to identify material from qualified suppliers and to identify specific material sources for tracking, ordering, and generation of “equivalent-material” lists. Material definitions contain vendor specific nominal values for material properties, such as percent purity or hardness. Each material lot defines a specific quantity of the material, as well as properties of the material. The properties may be determined locally, through incoming inspection and laboratory analysis, or may come externally through certificates of analysis. Material lots are used for tracking the status of the material, such as provisional, tested, released for production, or released for shipment. Material lot identification is required for tracking and tracing and for the creation of a material genealogy for products.
Material lots may be stored in multiple containers, such as a single material lot of screws that is stored in multiple cartons. Each separately stored amount is identified as a material sublot. Material sublots may have separately maintained quantity and location information, and the sublots may also have unique properties, such as RFID identification or qualification status.
Material class, material definition, and material lot information are used in the ERP system and MOM systems. Material sublots are used at the MOM level, but may also be used in the ERP system, if the ERP system tracks inventory or schedules production below the lot level. Usually the ERP system is the custodian of all material information, while the manufacturing systems update the information with quantity and location changes and with new values for material properties.
A common practice is to keep copies of the ERP information at each manufacturing site so that the information is available when the ERP system is unavailable. Many companies are now using the WBF B2MML standard ( www.wbf.org ) as the integration standard between their ERP system and manufacturing systems, and often the first integration project is sharing material information. Remember to handle all three material information types; material class, material definition, and material lot in your integration projects.