This post is soliciting the opinion of ERP experts, to answer my question “When are production orders derived from the MBOM versus a collection of process plans?
Production Order Definition
A production order represents the manufacturing work to produce / assemble / manufacture, a product. At the risk of stating the obvious, a key element of a production order is therefore the product being manufactured.
A production order has a routing, also known as a process plan. This is the collection of work (operations, steps, required tools, required labor skills, required tests and data collects, work instructions, etc.) that needs to be performed in order to manufacture the product.
Often, a production order has a BOM, also thought of as the manufacturing BOM, or MBOM. This contains the components that make up the product. Each component is referred to in the process plan.
If our product is a skateboard, the routing contains the operations to assemble the skateboard, and the MBOM contains the wheels, axles, board and nuts & bolts. A production order to manufacture one skateboard, once completed results in a unique, physical skateboard.
Applied to Complex Assembly Manufacturing
Now consider a complex assembly manufacturing environment. The product being assembled has ‘000s of components. It could be an engine, an escalator, a fuselage, an industrial air conditioner, a drone, an aircraft, a satellite, a train, or any number of high value products that Dassault Systemes’ customers manufacture today. Often it takes weeks to assemble one of these products, and the work is spread across multiple production orders. Multiple production orders, instead of a single production order, are used to effectively manage business processes such as procurement, planning and scheduling, material kitting and movement, tool & labor allocation and planning, and change management.
If we return to our initial definition of a production order, multiple production orders imply that there are also multiple process plans and multiple products being manufactured. While multiple process plans is easy to comprehend, multiple products is not.
As an example, if our product is now a helicopter, and the entire assembly process is spread across 10 production orders, it makes sense that there would be a collection of 10 process plans to assemble the helicopter. Install Rotor, Install Cockpit, Test Flight Controls, etc. might be good names for some of the 10 process plans.
But what about the 10 different products, one per production order? Has a product been produced after the ‘Install Rotor’ production order has been completed? No. In fact, each production order is just a different part, or stage, of the overall process plan to assemble the helicopter. Shouldn’t each production order simply reference the end product, the helicopter?
MBOM-Based / MRP-Driven
Although using the same product (Helicopter) for each of the 10 production orders required to assembly the helicopter seems to be a good approach, many manufacturing companies actually create 10 additional ‘fake’ products, and represent them as children of the helicopter in the MBOM. For example, there’s a product called ‘Install Rotor’ in the MBOM. But why would you do this? One reason (maybe there are more) is that an MRP algorithm generates these orders from the MBOM. If 10 production orders are needed to assemble a helicopter, then 10 different products are needed in the MBOM in order for the MRP to generate the orders.
Process-Based
In the case of some very complex, final assembly manufacturing, like the assembly of a commercial airplane, an “MBOM-Based / MRP-Driven” approach is NOT used. In this case, there are often ‘00s of production orders required to assembly a single product. Many of these production orders have no components, and thus no link whatsoever to an MBOM. Think of all of the activities related to testing, verifying, inspecting, cleaning, etc. But each of these production orders still have a process plan. And some system, or person, creates a production order for each of these process plans, with the product being the commercial airplane.
My Question
My question is, what criteria is used by a complex assembly manufacturer to decide which approach to use?
- MBOM-Based / MRP-Drive – Production order creation is the result of an MRP algorithm where each production order has a representative product in the MBOM.
- Process-Based – Production order creation is the result of a system, or person, creating one production order per process plan required to assembly the product.
The answer to this question impacts how the 3DExperience MBOM and Process Plan is modeled.
