Manufacturing Execution Systems or MES are computerized systems that help create flawless manufacturing processes and, in real-time, provide users with details of changes to requirements. MES is essential for the successful manufacture of many goods.
An example provided by Joseph A. Vinhais of CIMNET inc. says the production manager of a toy manufacturer needs to know when the company's popular remote-control sailboats will be available after an extensive redesign. She must verify that product has begun, determine the new manufacturing cycle time, obtain results from product testing, and check the materials inventory and projected shipping schedule.
Rather than going from department to department, or looking in several separate databases, she uses the company's MES, which may not only provide the information directly to her terminal, but distributes her revisions to all relevant parties.
MES technology has become a key element for enterprise solutions. The system provides a central information hub of 11 decision-based functions that link to other databases. These elements, combined with an enterprise resource planning system and a control system such as PLC, SCADA, MMI, or HMI, provide the means for a paperless factory. Currently, companies in the aerospace, automotive, semiconductor, pharmaceuticals, and petrochemical industries have adopted MES.
In essence, a full MES solution bridges the gap between the production/assembly floor and engineering, accounting, production control, purchasing, configuration management, quality, manufacturing engineering, process engineering, research and development, and testing. MES functions as the central depository for data distribution and collection for all other enterprise systems.
MES and Document Control
Full MES solutions provide tools for document control and management. Authorizing and editing documents is controlled through an electronic engineering change notice. Hard copy ECNs have been used for years to control revisions of engineering drawings. Today, however, companies distribute many more documents to their production and assembly departments. These documents, as well as engineering drawings, are created by electronic systems such as computer-aided design (CAD) and manufacturing, word processing, spreadsheets, graphic imaging, and forms tools.
When used in conjunction with MES, document control manages each document's revision and can associate the appropriate documents by part numbers, work center, operation, job/work order, and assembly number. This ensures that an operator or assembler won't retrieve an obsolete revision to perform a specific process. Quality documents such as manuals, inspection sheets, corrective action tracking reports, control plans, warranty procedures, vendor certifications, process specifications and the like, can be controlled by a MES document control system.
MES and Data Collection
Many tools in today's manufacturing environment collect data -- bar coders, forms, handheld statistical process control data collectors, electronic gages, and others. Typically, manufacturers invest in different devices for each implemented system. When acquiring an enterprise resource planning system, for example, manufacturers usually purchase a bar coding system to collect data associated with work orders. Bar code stations, strategically located throughout the manufacturing facility, usually cause queues of operators and assemblers logging in and out of jobs.
The bar code system primarily collects labor information. Manufacturers also must invest in a separate system to collect quality or SPC data. This usually entails creating, distributing, and filling out forms. Although most SPC systems are networkable, a high percentage of them consist of stand-alone PCs with handheld data collectors.
The MES system replaces these cumbersome manual activities with electronic data collection on the shop floor, which can be transferred to management, the front office or back to engineering.
In summary, an MES provides all the necessary and correct information to operators or assemblers at the correct time. Quality, manufacturing, and engineering data stored in separate databases is accessible across the network for combined reporting. A MES also allows operators to request resources from other department databases linked within the system. In short, an MES gives a quality department the means to support its internal and external customers more easily, quickly, and with much more data.