MES vs. ERP: Understanding the Difference and How They Work Together

[@NickNiculita-nicks-software]

People often get confused about MES and ERP systems. They think they're competing solutions, but they're really two different layers of the manufacturing stack. It's like comparing your brain to your hands - they both matter, but they do completely different things. ERP is the business brain. It handles all the thinking about money, planning, and resources. When you need to know how much something costs, or whether you have enough raw materials to make it through the month, that's ERP territory. It's built for people in offices making business decisions. MES is more like the hands - it's where actual making happens. It's down on the factory floor, tracking each product as it's made, monitoring machines in real-time, and making sure everything's running right. When an operator needs to know what to make next or a machine breaks down, that's MES territory. The interesting thing is that most companies get this backwards. They buy an ERP system first, then realize they can't track what's actually happening on their factory floor. It's like buying a fancy chess computer but having no way to move the pieces. The smartest manufacturers figure out that they need both, working together. ERP sends down the plans - what to make and when. MES executes those plans and sends back what really happened. Without this connection, you're basically running your factory blind. The trick isn't choosing between them. It's getting them to talk to each other properly.

[@mapyn131]

many businesses apply a process known as mrb, is this quality process managed in erp or mes in this new world?

[@sherylmccrary9045]

In general, the *documentation* (MRB as in manufacturing record book info) would be in the ERP (design and material spec compliance, asset/equipment certification), maybe even in a contracts module if customers have different requirements. *Source data* and process records would be in the MES, plus a Quality Management System for test records, engineering systems for design, etc. In industries where this is a big deal, there are apps specifically for the record book process. If you’re referring to a formal Material Review Board process --- ie engineers have to examine quality rejects to determine whether to scrap, rework, or return materials --- at minimum, the ID’d pieces, counts, material source, etc. would be in the MES. Not saying that’s the way it is. I worked in a build-to-order environment in which every order, starting with the sales proposal, required team approval for components, performance, deliverables. The sales quote became a sales order, which created a production order, which created separate assembly, configuration, and installation work orders. Some customer requirements were actually in the CRM with no links to the ERP.

[@mapyn131]

leaving scrap reporting at the mes level?

[@4.0Solutions]

Scrap counts and tracking are in MES, scrap classifications (the rules) live in ERP.

[@akshaygoyal885]

But I thought in the other video, you said that production scheduling and optimization is done in the MEas layer. Now I am confused 🤔

[@serdargokay2503]

I couldn't understand the same point.

[@walkerreynolds973]

There is two types of scheduling - there’s the scheduling and resource allocation of a sales order (production order) which is tied to what the customer or distribution center ordered/bought. Then there is the scheduling of the manufacturing (work orders) order which is the scheduling of the individual steps that make up the production order sales order. When talking about scheduling I generally try to qualify that manufacturing orders (the individual steps in the manufacturing process) can live in either ERP or MES but SHOULD live in MES. When it comes to sales order or production order scheduling and resource allocation, that’s is almost always in ERP. A good example is this Customer A order 100k widgets - there is a single sales order in the ERP for that customer for part A, 100k widgets due on X date. Planning does resource optimization analysis and determines that we need 2 production orders of 50k widgets one at site A and one at site B - again, done in ERP. The orders are pushed to Site A and Site B and then broken into manufacturing orders that live in MES. Transactions are pushed up to ERP as manufacturing orders are completed. 🙏

[@ZackScriven]

@@walkerreynolds973 thanks for the explanation!

[@aldhal202]

Here is how i would explain it: the week month scheduling happens usually in ERP based and ERP is only concerned about planned downtimes. Once the production orders are released to MES, the erp schedule is the time plan against which typically it shall be executed. From now on the unscheduled shall be considered the schedule must be adjusted based on asset state for the upcoming hours or 1 or 2 shifts. This is where MES scheduling comes into picture and the shift supervisor has to adjust the schedule in MES for the upcoming Hour(s) or current next shift if impact is that long.

[@serdargokay2503]

Thanks for the explanation 🙏

[@kisin]

Just what I needed! I was wondering how do you treat manual labor though. In our case labor hours are captured directly in ERP layer. Should this go through the MES layer instead (ie the worker as a machine)?

[@omoklamok]

as i understand labor doesnt side on erp unless the bom calculation included labor as part of the costing

[@4.0Solutions]

If labor is part of the BOM, it’s calculated in ERP. If not, it’s tracked in MES and reported to ERP if needed.