MES in vehicle manufacturing - Welding & Order Release

Normally vehicle manufacturing is scheduled by Work Orders.

There’s a term OTD(Order To Delivery), means the whole process from creating Sales Order to delivering product.

Based on customer request, market investigation and forecast, shop dealer create Sales Order in car maker’s sales system.

Sales system will bind the information with market strategy, then release Sales Order.

Then Sales Order is loaded into plant’s ERP system, which will check with plant calendar/machine status/material storage/purchase plan, then run MRP/APS, and create daily Work Order for it.

And then SRM system will generate component delivery request, and send it to vendors.

After vehicle is built, it will be transported to dealer.

Diagram 2.2-1 shows OTD flow:

 

Diagram 2.2-1: OTD flow

Normally for process of punching, welding, painting, and assembly, each process costs 1 day for manufacturing, and then costs a couple of days for transporting. ERP will base on Sales Order to generate Work Orders of Assembly Shop, then create Work Orders of other 3 shops accordingly.

ERP Work Orders have the vehicle data such as model type, they also show the building sequence of each day.

But in Punch Shop, because it uses batch build model, it will not follow the Work Order sequence strictly.

In Welding Shop, MES downloads ERP Work Orders, and generate daily MES Work Orders. In MES, planners can lock/freeze/re-sequence these Work Orders, so the final sequence could be different than original sequence.

After completing welding, vehicles come into Paint Shop through WBS, these vehicles can be re-sequenced according to WBS routing rules.

After complaint painting, vehicles come into Assembly Shop through PBS, based on PBS routing rules, normally vehicles will be re-sequenced based on model type, VIN numbers, etc.

Normally only Welding Shop’s Work Order sequence is highly aligned with ERP planning.

In Welding Shop, MES needs to accomplish these planning functions:

1) Download Work Orders from ERP automatically.

2) Lock, freeze, re-sequence Work Orders.

3) Validate Work Order, such as to check process readiness.

4) Send Work Orders into PLCs of main line and sub-assembly lines.

5) Broadcast Work Orders to later stations.

As showed in diagram 2.2-2:

1) MES releases Orders into stations of Front Floor, Back Floor, Front Cabinet, and SL010/SR010/SL070/SR070 of Main line.

2) In UB010 merge station, PLC will check if the components from 3 sub-assembly are matched, if so then generate VIN number for it.

3) When vehicle comes to main line, PLC will check if it matches with components from sub-assembly lines, if not then get component from buffer zone.

 

Diagram2.2-2: Order release in Welding Shop

At Work Order downloading stations, device PLC downloads Work Order data from MES, including: Sales Order, Work Order, VIN number, model type, vehicle attributes, etc. The key data will be written into RFID Tag in merging station.

As off-line buffer, normally PLC will buffer Order data of 3~10 vehicles.