John Hayes, the president of engineering.com, says that PLM should own the BoM.
Some years ago, I was working with a company that makes machines that make computer chips. We were discussing their bill of materials. They really didn’t want their machines to be ‘one-off’s’ but in order to meet the needs of their customer, they wanted to be responsive.
In their case, they had multiple views of the bill of materials.
As Designed – They had a bill of materials that was created in engineering representing the original design of the machine.
As Planned – They had a bill of materials that was modified for manufacturing. This BoM represented what they intended to manufacture.
As Manufactured – This BoM represented the machine that was manufactured. Their customer would often provide input during manufacturing that would change what got manufactured.
As Installed – While installing the machine, further changes were made to the BoM. Even after the machine was installed, changes could be made.
As Maintained – They needed a BoM that represented the machine as it is currently configured so that it can be maintained properly.
Typical BoM ownership
The as designed BoM is owned by engineering and usually resides in their PLM software.
The as planned BoM is owned by manufacturing [and finance] and usually resides in ERP software.
The as manufactured BoM is owned by manufacturing and should be found stored in ERP software.
The as installed BoM is owned by the service organization. They may have their own software where this BoM is stored or it could be stored in the ERP.
The as maintained BoM is owned by the service organization. Often they have their own software where they store the information that describes the difference in the BoM’s.
If all of this is true, what happens when engineering attempts to create a new model of this machine? Which bill do they start with? They should start with the latest version of the product – the as maintained BoM. How do they get it?
If you employ a strategy to use PLM software to manage changes to the design [all of the different BoM’s] then a change request must be created for each and every change to the as designed BoM. The PLM software will be the change manager and will always have the latest BoM. Engineers will know that the single version of the truth can be found in the PLM software. However, the PLM software should publish the latest BoM to the ERP so that anyone outside of engineering can also see the single version of the truth.
PLM software will be able to show you these 5 different views of the BoM when needed whereas typical ERP software will only show you the latest. Many companies have successfully employed this strategy.