The Product Definition Challenge

May 25, 2009

To develop a product and ultimately maintain an asset you need to manage a number of product definitions going through the lifecycle from inception to disposal. Some product definitions are critical as part of EAM/MRO.
In this post I’ll talk about product definitions in general an then specifically those that are input to EAM/MRO. Literature may refer to these product definitions as BOM’s. I oppose this generalization as there is more ‘bom to a bom’. A ‘decomposition’ would be more appropriate and this decomposition consists of Assemblies. I once referred to these as bom-lets, in fact that is exactly what it is, small structures of sub-assemblies with components.

In general there are 4 key product definitions (decompositions).

  1. Functional decomposition which is very much related to the requirement definition phase. Requirements must be recorded in a decomposition as these requirements branch out from systems to parts and their positions.
  2. Derived from the Functional decomposition is the Engineering decomposition. In general this definition is system discipline oriented. In aerospace these systems would be ATA chapters and for power plants the breakdown according to the Reference Designation System. In the Defense world this definition refers to the Physical decomposition. It is important to appreciate that this definition represents the certified product. For those from Aerospace it is the (Type) Certificate. The V-model I talked about in this blog is the corner stone to this certification as it is linked to the original requirements.
  3. The third decomposition is concerned with the Production definition i.e. the build sequence (final assembly schedule) and this definition Consumes (uses) assemblies defined in the Engineering decomposition. It will be the source definition for manufacturing instructions. Today these instructions are rich content and include text and graphics.
  4. The fourth decomposition is concerned with the Maintenance/Service definition i.e. disassembly sequence and product support and this definition also Consumes the assemblies defined in the Engineering decomposition. It will be the source definition for maintenance instructions and part catalogs. Today these instructions are rich content and include text and graphics. I believe that this definition is also the source of maintainability and reliability analysis and for this reason it is the base for product failure records and technical communications with the field.

prod def cycle 2

In today’s environment it is a challenge for companies to develop a product and the different product definitions synched without the support of various PLM capabilities. To make matters even more complex, each of the decompositions 3 and 4, in fact have ‘children’ and the correlations with the parent are extremely important as part of (regulatory) compliance. The child of:

A) The Production definition is the As-Built, and is controlled by Manufacturing Execution i.e. the ERP execution.
B) The Maintenance/Service definition is the As-Maintained, and is controlled by the Maintenance Execution i.e. EAM/MRO execution.


These last two are in fact physical instances and represent the actual asset itself. A) as it is delivered to the client and B) as it is maintained/operated. It should be appreciated that A actually feeds B as the asset is delivered to its owner. In aerospace this could be considered the Equipment list or Inventory record. See figure regarding connections.

MRO solutions depend on an asset master configuration record (MCR) and unit configuration record (UCR). The MCR defines the generic part number decomposition and the UCR the serialized structure. For example there is a MCR for a fleet of Boeing 737’s and each unit (tail number) is derived from this. The same applies to engines; for example the RR Trent 700EP is the MCR (model) and the individual engine is the unit record.

The master configuration record typically consists of part numbers only, whereas the unit record is a combination of part numbers AND serial and lot numbers. Part numbers are ‘positioned’, for example the same valve can appear in two different locations and these locations are recorded as positions.

Working with several OEM clients we encountered challenges concerned with the as-built/delivered asset definition i.e. the equipment list of the as-sold configuration. The as-delivered in principle is based on a production planning definition, conceptually analogous with the UCR and MCR. In several cases this production planning definition could not be used as input to MCR and for this reason the client used the engineering definition instead (based on tail number configuration). The challenge was the separation of the engineering definition with the equipment list.
We also ran into a situation where the asset documentation basically was the engineering definition, and restructured to become the base of the product catalog. The only possibility to synch the product catalog were the engineering change records. Also maintenance procedures where based on maintainability analysis and recorded against maintenance significant items and these were different from the engineering definition source.
A challenging mix of definitions. Obviously these organizations are depending on significant engineering knowledge to bridge these ‘broken’ definitions.
Our recommendation to these clients consisted of an enterprise wide analysis what kind of product definitions existed, for what purpose, what challenges these organizations encountered to synch between different disciplines and finally the ‘cost’ of these inefficiencies. We also looked at the business goals and current technology. From this information we then developed a change plan. Several of these clients incorporated this recommendation in their short and mid term planning.


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