What is a Manufacturing Execution System (MES)?
A Manufacturing Execution System, also known as MES, is a powerful production-oriented software used to gain real-time visibility of operations.
Gartner provides a useful definition:
"Manufacturing execution systems (MESs) are a class of software that manage, monitor, and synchronize the execution of real-time, physical processes involved in transforming raw materials into intermediate and/or finished goods.
They coordinate this execution of work orders with production scheduling and enterprise-level systems. MES applications also provide feedback on process performance, and support component- and material-level traceability, genealogy, and integration with process history, where required."
Despite their differences, all MES share a number of core features. Some MES do certain areas better than others, but they are all expected to have at least some of the following “modules”:
MES Core Functions
- Product Documentation
- Product/Part Tracking and Genealogy
- Process Execution Management
- Resource Management
- Quality Management
- Human Resources
- Data Collection
- Systems integration
However, no two factories are alike. Needs vary from industry to industry and according to the type of manufacturing operations. Batch manufacturing operates quite differently than discrete manufacturing and so on.
This snowflake-like variety between factories has foiled attempts from organizations such as MESA and ANSI to standardize the definition of MES.
In this post, we’ll look go deep into the core features that usually make an MES.
Let’s start by looking at the functionality and features that each of these modules can provide.
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Manufacturing Execution Systems manage the documentation required by the shop floor to manufacture a product. This is accomplished through features such as:
- Bill of Material (BOMs) Management: Either receiving a manufacturing BOM (mBOM) from an external system or receiving the engineering BOM (eBOM) and managing the transformation from eBOM to mBOM within the MES.
- Change and Configuration Management: Management of product revisions so that when a product is updated, the process plan can be updated with revision control and reference to the relevant changes in the product definition’s eBOM and CAD models.
Product and part tracking and genealogy
These MES features seek to ensure the availability of the right parts at the right place and time within production. Among them are:
- Part issue: Track parts from the time they are issued from stock as they are moved through shop floor storage areas until they are installed or used by a production operation.
- Part picking: Generate parts pick list that is either sent to the inventory system or carried manually.
- Part Kitting: Generate a kitting list for parts to be kitted together in bins or carts before starting a job in order to ensure all parts are available in the process.
- WIP inventory levels: Keep track of WIP inventory levels of parts issued to jobs, but not installed, and transmit the information back to the inventory system.
- WIP product tracking: Track products as they move from one work center to the next. This is done through the use of barcode scanners or by tracking serial number, lot number, or work order number.
- Parts installation records and product genealogy: Maintain a product history and audit trail, including a complete genealogy of the materials and components used in the assembly. The MES can also verify the as-built BOM against the as-designed or as-planned BOM.
- Material shelf life and expiration: Keep track of material expiration dates to prevent workers from using expired materials.
Process Execution Management
Manufacturing Execution Systems offer features to manage production and ensure the right workflows are followed, such as:
- Process Routings: Define and manage the process plan, which details execution sequence rules, work instructions, resources, and data collection requirements for each operation and step.
- Work Instructions: Digital versions of work instructions with text and illustrations that guide the technician through the appropriate process sequence – how to set up tools, position parts, run machines, and perform verifications along the way.
- Guiding through work steps: Beyond work instructions, MES can guide the technician through the various steps from selecting a job on a dispatch list, signing on to the job to start the clock, collecting data for measurements and parts, through recording the completion of the job.
- Production Job Progress Tracking: Track the completion of orders by operation area, resources used, bills of materials, and parts used, so production planners can identify where each unit or lot is within the manufacturing cycle, what materials are needed, and when. This level of visibility helps engineers plan inventory, schedule production, and accurately inform customers when orders will be ready. By requiring personnel to clock-on at the start and end times of a job, this function can help track labor costs for each job.
- Events and Alerts: Record events such as the completion of a job by a machine or operator and trigger alerts via email to the supervisor or support as needed. For example, an alert might be fired if an out-of-spec condition is met, if a line stops, etc.
- Production Control: These features provide the ability to expedite the resolution of issues that are holding up production, coordinate and approve work-around deviations from planned work and incorporate urgent engineering changes that impact production schedules. Usually, production control features provide screens and reports to help personnel analyze impacted areas and help solve them as fast as possible.
- Production Jobs Dispatch: Provide a daily job dispatch list from the ERP and offer the ability to postpone jobs, work around unplanned issues, and so on. This functionality usually has graphical displays such as Gantt charts to assess the performance and track if jobs are falling behind or on track to be completed on time.
Features to manage resources in production, such as tooling, materials, and so on.
- Control Station / Planning Table: The planning table contains a periodic view of the master plan with the planning and control tools necessary for maintaining production quantities to ensure a smooth production process, a process’s planned orders, and production orders.
- Tool and resource management (TRM): Manage the tools and other auxiliary materials and equipment needed in production. More than an inventory system, the MES is expected to manage the state of operating resources, determining what tools are available, which ones are compatible with which machines and evaluating their condition with the goal to do preventive maintenance and reduce downtime.
- Tooling Calibration: Related to TRM, since the MES has useful information for each tool, calibration can be triggered based on the actual usage frequency. Furthermore, the MES can enforce that tools are properly calibrated before they can be used.
- Transmission of machine settings: Manage and transmit machine settings to ensure the right setup and maintenance for every machine, as well as work instructions to properly run it, with the goal of avoiding unnecessary downtime.
- Running Machine Programs: Store and manage programs for running machines, from simple setup sheets to numerical control (NC) or coordinate measurement machine (CMM) programs.
- Material and production logistics: Supply information about material in circulation (those concerned with work in progress (WIP) or outside of the common storage facilities) so that their transportation activities can be initiated at the right time.
Integrate quality in the production process through in-process verification.
- Statistical Process Control (SPC): Statistical Process Control captures data, processes it, and compares it with set point values to determine if it is within tolerance. If it is not, then the SPC function can trigger an alarm to warn the relevant stakeholders. MES systems should save these captured data points to keep track of their trends and make them available in production to identify and prevent mistakes before they happen.
- Product Configuration Verification: MES can help ensure that products are built to the correct engineering specifications by keeping Device History Records (DHR, also known as As-Built reports), which include a list of Engineering Change Notices (ECNs) incorporated into each product unit. If there are deviations between the as-built and as-designed configurations, the MES can manage the approvals necessary to ensure manufacturers don’t ship products outside of specification.
- Non-conformance Management (NCM): Traceback the technical aspects, manufacturing conditions, and input materials of products that have poor quality, with the goal of introducing and measuring the effectiveness of countermeasures.
- Incoming goods: This module helps register and keep track of incoming and dispatched goods to ensure accurate batch numbering and alert stakeholders if values are out of tolerance levels.
- Inspection equipment management: Similar to Tool and Resource management, this feature helps make sure the inspection equipment is properly maintained. It also ensures that the equipment meets the required standards and that it is being used for the appropriate tests and inspection procedures.
- Process Data Processing (PDP): This feature captures data from production, such as temperature and humidity, and verifies them against tolerance or intervention limits. If an error occurs, it recommends countermeasures.
These features help manage the people involved in operations.
- Staff work time logging: Keep track of staff clocking-in/clocking-out data as well as absence times and other time-related variables that can help production, especially when labor has to be scheduled efficiently.
- Personnel Qualifications and Certifications: Maintain certification records for employees as well as their experience with different types of jobs. Verify that employees signing on to a job have the necessary certifications and experience in order to perform it.
- Incentive wages: Implement incentive-based bonus systems, using production data, absence times, and work order times to calculate performance levels.
- Short-term manpower planning: Get an overview of all the active personnel so you can plan schedules either manually or automatically, taking into account loading situations on a departmental, plant, or company level.
- Access Control: Manage access control to the production facility to ensure only authorized personnel can access the shop floor, operate machinery, and so on.
- Escalation Management: Escalate issues related to quality, utilization, downtimes, and so on. If thresholds are violated, escalation and alarm mechanisms are set off to escalate the issue and alert the right stakeholder to reduce the length of faulty operational states.
MES help with data collection and integration throughout the shop floor.
- Production Data Acquisition: Capture production data from people, material consumption, and quality over various time-frames and make it available to management in real-time through displays and analyses.
- Machine Data Collection: Capture machine status manually through interfaces or automatically through industrial protocols and bus systems or sensors such as scales, balances, and measure KPIs such as OEE, uptime, and so on, as well as to identify bottlenecks and points of failure in production.
- In-process data collection: Facilitate manual and automatic in-process data collection using checklists and recorded measurements as well as devices such as barcode scanners, RFID, gage interfaces, and so on.
MES should be able to integrate with other production systems.
- Data storage: MES should have up-to-date and standardized data. It should be able to talk with existing databases in the company as well as new ones through APIs, connectors, or others.
- Integration with other systems: The MES should be able to integrate and interact with other systems in the company. On the corporate level, it should be able to interact with the ERP, personnel, and QMS systems. On the production management level, it should be able to interact with machines through industrial protocols such as OPC-UA as well as PC-based inputs from information stations.
- Deployment: Most MES are on-premise, but there is a growing trend towards cloud-based MES from the leading vendors, and new players have been emerging that are increasingly cloud-native.
Even though each MES has variations based on industry, type of manufacturing operations, and customer size, they all share some combination of the features listed above. When properly implemented, MES gives manufacturers real-time visibility to make better decisions. However, due to the rigid nature of their technology, MES are challenging systems that take time to show ROI.
New technologies such as manufacturing apps let modern manufacturers access many of the core features listed above, without the common challenges of MES. With operations platforms such as Tulip, each of the MES features listed above can become an application specifically designed and developed by those closest to operations.
For a comprehensive review of how Tulip stacks up against traditional MES solutions, check out our MES vs. Operations Platforms guide.
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