Definition
ERP (enterprise resource planning) manages a company's administrative backbone: customer orders, stock, purchasing, routings, booked hours and invoicing. MES (manufacturing execution system) operates closer to the shop floor, driving and recording production execution in real time, such as which machine is running what job and current progress.
Why ERP and MES data isn't always synchronized
An ERP's data is only as current as what gets entered into it, often after the fact, while an MES aims to capture what's happening on the floor in real time, which is why ERP and MES data can sometimes disagree until one is reconciled with the other.
Where each fits in a factory
Neither appears on the drawing; both are internal factory systems, relevant to how orders are managed and tracked rather than to the part's technical requirements.
Common mistakes
Assuming ERP and MES serve the same purpose, or that a factory only needs one; ERP handles business administration, MES handles shop-floor execution, and many factories genuinely need both, though smaller shops often blend the functions informally.
An ERP's data is only as current as what gets entered into it, often after the fact, while an MES aims to capture what's happening on the floor in real time, which is why ERP and MES data can sometimes disagree until one is reconciled with the other.
See how Blake reviews a partFrequently asked questions
Does every factory need both ERP and MES?
Larger or more automated factories often benefit from both; smaller shops may handle MES-like functions manually or within a simpler system.
Which system tracks the actual machining time?
MES is oriented toward capturing real-time shop-floor data, including actual machine run time, more directly than ERP typically does.
Can ERP and MES data conflict?
Yes, since ERP data often reflects manually entered or batch-updated information, while MES aims for real-time floor data, discrepancies can arise until reconciled.