Planning - MES in Vehicle Manufacturing

Due to unique process of vehicle building, the planning of MES implementation is very different than general software system.

 

1.    Milestones

Building a vehicle plant has these milestones:

-          TT, short of Tool Tryout, or Tooling Trial, is referring phase of equipment setup and configuration, MES is cut-over during this phase.

-          PP, short of Pilot Production, the Logistics Execution System is cut-over during this phase.

-          SOP, Start of Production, ERP system is cut-over during this phase.

For ERP system, normally we’ll setup test system at first, then prepare master data, then configure and test, finally load data to production system, and cut-over during SOP.

But for MES, it needs to integrate with lots of equipment, and we must use time window of TT to test.

Normally on TT phase, there’re few vehicles available for test, only a couple of vehicles for each shop, and will stop in case of any issue. But since PP, the daily planning quantity will increase, so it’s not suitable for handling any test related to interface with equipment.

There’ll be a couple of months between TT and SOP, which brings a challenge of project management: MES and ERP are normally managed by same IT program, but since they have different cut-over time, so it will be quite difficult to align planning and resource.

 

2.    Develop pattern

MES is cut-over at TT, which brings concern of develop pattern.

In recent years, affected by internet development, agile develop pattern is quite popular, but in vehicle building MES area, traditional waterfall + modular pattern is more suitable.

Consider that equipment integration should be ready and tested in TT phase, and ERP interface should be tested in SOP phase, so we need to develop and test equipment integration module in advance.

Another feature of MES is: Normally we setup production system, then develop and test in that system directly. There’re 2 reasons: firstly, the test of OPC&PLC must be referred to physical servers, the successful test on test system doesn’t mean success on production system. Secondly, in production system, there’re availability mechanism such as data guard of Database, load balance of Web Server, and cluster of Application Server, and such features cannot be tested in test system.

 

3.     Equipment Debugging

For MES, the debugging/test of equipment integration are planned at TT phase, when the plant is still under construction, for some area the power and network might not be available yet, which requires temporary power and network, so lots of stations might need a couple of turns of debugging.

Each function module should go through these debugging process:

-          Power and network test, to check infrastructure such as O/S, client, network.

-          Communication test, also known as heart beat test. Equipment PLC sends out a heart beat signal, then MES receives it and responses back. This step is to check the basic handshaking between equipment and MES, it could also check communication parts such as Couplers.

-          Virtual business test. Before physical vehicle is available, PLC/HMI sends out virtual business data, then MES responses according to business logic and handshaking protocol accordingly. The reason is that there’re only few vehicles available at TT phase, and there’re lots of stations require debugging, so we need to do as many tests as possible while IE engineers are available.

-          Physical vehicle test. It happens after virtual business test, to check the physical devices such as sensors, encoders, and also do final test of whole process.

In debugging phase, different debugging process might happen in same time. For example in Welding Shop, there’re 10+ IE engineers, but only 1 MES engineer, so the MES engineer might debug heart beat at one station in the morning, and test virtual business at another station in the afternoon.

As per detailed time planning, we should reserve 1 week for the 1^st station covering all test process, because the 1^st station covers lots of common issues such as setup of OPC and Gateway. Then for 2^nd and 3^rd stations 3 days should be reserved for each one. After that reserve 1 day for each later station. 2 weeks later reserve half day for each later station.