Manufacturing execution systems (MES) manage operations on the shop floors of factories. Some MES support a single class of machine; others are designed to oversee operations on the entire floor. We wrote this buyer's guide to explain MES technologies and assist buyers in making a selection.
Here’s what we’ll cover:
“If you build it, they will come,” is not a quote about manufacturing, but the concept is related. MES software manages operations on the shop floor. The scope of MES can vary from scheduling a small set of critical machines to managing the entire fabricating operation for a manufacturer. In all but a handful of cases currently, the MES does not directly control a machine but rather tracks the work-in-progress on the shop floor.
MES is a subset of enterprise resource planning (ERP) systems and executes the plan determined by the manufacturing resource planning (MRP) system. The functions of MES programs include: compiling a bill of materials, resource management and scheduling, preparing and dispatching production orders, preparing work-in-progress (WIP) reports and tracking production lots. Advanced systems will also have a product definition library with revision history and can report on production status to an ERP. In contrast, an MRP system sets the production schedule, determines the make versus buy list and determines inventory requirements.
The MES is responsible for scheduling and tracking each step of the production phase of a particular job. It prints out the bill of materials that the operator will require and production steps to complete at each phase. It repeats this process for each operator and each step until a particular job is complete.
MES is not generally effected by a manufacturer's mode, be it make to stock (MTS), assemble to stock (ATS), assemble to order (ATO), make to order (MTO) or engineer to order (ETO). This is because by the time the MES is invoked, the parts and schedule are already set, usually by the MRP system.
MESes are generally installed on-premises, but cloud-based solutions are becoming available. In most businesses, one of the reasons for having a cloud-based system is the reduced initial cost for equipment. This is not necessarily true for manufacturing; if the system has just a few users then they are usually located in the same facility and it is just as easy to link them to each other as it is to give them access to the Internet. If it is a large implementation, the expense is in creating a robust network and acquiring suitable fixed and mobile workstations. The incremental cost difference between having a server for the software is generally minimal. Instead, the benefit of cloud-based systems is the reduced cost for system management; the servers are out of the shop floor environment, can be backed-up and replicated automatically, and do not have to be maintained by trained on-site personnel.
The first step in evaluating MES software is to determine what type of buyer you are. Over 90 percent of software buyers fall into one of these three groups:
Enterprise resource planning suite buyer. These buyers value the seamless integration of data and processes that comes from having one system for all functions. For example, they would prefer a full-suite system for estimating, work-in-progress management and accounting that can automatically turn an estimate into a budget for project management and then match invoices to project status and allocate job costs. These buyers favor complete software suites from companies like Oracle, SAP, Sage ERP or Microsoft Dynamics.
Departmental buyer. Specialists in one function, such as creating process set points, may value the feature depth of best-of-breed solutions designed for their function. These buyers may need specific functionality, like the ability to interface with a specific computer motion control system.
Small manufacturer. Small organizations often have limited budgets and fewer IT resources and tools to dedicate to software. In many cases, they may be deciding between a new software system and a new piece of equipment. These buyers need cost-effective SMB manufacturing solutions that are easy to implement and use. Some will prefer full-suite systems, while others may just want one application, such as bill-of-materials production or shop equipment scheduling operations.
Increase utilization of equipment. MES systems let manufacturers measure the actual utilization of equipment. With this knowledge, you can adjust job prices to either encourage the use of certain equipment or dissuade the use of that equipment.
Better record-keeping and data analysis. MES provides records not of machine use, jobs and lots. This yields several benefits. First, there is better tracking of actual materials used, increasing accountability of material use to individual operators, which generally reduces waste. Second, should a quality problem occur, lot tracking allows tying back the issue to the individual lots instead of having to potentially recall an entire run.
Real-time WIP reporting. MES systems can report on progress on jobs and lots in real-time, giving shop managers better information and allowing for modifications to the schedule to adjust for changes in productivity.
One of the big issues with implementing MES is the possibility it will be rejected by the shop floor personnel. Some workers find the method and amount of information collected intrusive. This can become a contract issue in a unionized shop. The best defense is to use a phased-in implementation coupled with training that emphasizes the benefits to workers.
Increased use of electronic documentation. Not so long ago, a shop floor had stacks and stacks of operator’s manuals, procedure manuals and material safety data sheets. Operators had clipboards and notebooks with bills of materials, work orders and reports. More and more, however, this paper is being replaced with electronic documents. MES documentation is no exception, most users produce electronic work orders and schedules.
Mobile devices used for reference and control. Related to the increased use of electronic documentation is the use of mobile devices on the shop floor. The days of using clipboards and paper kanban cards are quickly coming to an end. Instead, workers are using tablet computers and handheld devices to enter information directly into the MES system.
Increased integration with enterprise systems. Considering that ERP grew out of MRP and MES systems, it is no surprise that the integration with other systems is a continuing trend. Even stand-alone MES systems can receive data from MRP systems and inventory systems, and send information to others, like preventive maintenance systems (which track the hours that equipment has been used) and payroll systems (which track how much time workers spent on each job).
Machine integration. MES systems can now integrate directly with computer-controlled shop-floor machines, downloading directions and recipes when required.
Data consolidation and visualization. MES systems can collect and consolidate information from the various production systems. Production dashboards are beginning to make their appearance in systems, giving production managers a single view to track operations in real time.
|This type of buyer...||Should evaluate these systems|
|Enterprise resource planning suite buyer||Microsoft Dynamics, Oracle, SAP, Sage|
|Departmental buyer||Microsoft Dynamics, Epicor, SYSPRO, Casco|
|Small manufacturer||E-Z-MRP, ECi, Exact, Fishbowl|
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