The other day my son bought himself a new phone because the navigator in his old phone was defective. Every time that he used the old phone for directions, he would end up getting lost. Although taking the time to get a new phone wasn’t in his plans, he could no longer afford wasting time trying to figure out where he was and where he needed to go next.
His difficulties reminded me of the problems that I’ve seen in some PCB design groups where the design staff struggle with the creation of a bill of materials. Following the right steps for creating a BOM should be as straightforward as following a map to your intended destination. But if the process has problems, the efforts to create a correct BOM can be as frustrating as going west on the freeway when you were trying to go east.
Let’s look at what a bill of materials is and how it is traditionally created in the PCB design process. Next, we’ll examine how a PCB BOM created as a living document is different from the standard method of creation. Then we’ll discuss why creating a BOM as a living document is a huge advantage to the design process.
What is a PCB BOM and how is it created?
The PCB design that you create will need a list of parts to identify what and how many components are needed to be attached to the board during manufacturing. This list is known as the “bill of materials”, or “BOM”.
The BOM document is created as the PCB is being designed according to these steps:
As design engineers add parts to the schematic, those parts are added to the BOM by the engineers or other members of the design team.
As parts are changed or deleted on the schematic, the BOM is continually updated by the design team.
When the schematic is ready for layout, the BOM is updated with the component reference designators from the schematic.
After the layout is complete, the schematic is updated with reference designators that have been renumbered in the layout. Those updates are then updated to the BOM.
At any point in the design process when design updates require part changes, those changes are updated to the BOM as well.
Once the design is finalized, the BOM is compared to the layout and the schematic to verify that it is complete and correct.
As you can see, this is a complex process that is dependent on error-free manual input. The use of BOM management tools can eliminate the manual input and automate the creation of the BOM as a living document.
Bill of materials can be better managed online as a living document
Automated BOM creation as a living document
BOM management tools automatically compile the bill of materials data as a living document while the design is in progress. This gives you immediate access to the current BOM at any point during the design process.
In addition to an automated bill of materials report, BOM management tools will give your company many other advantages. Engineering and purchasing will benefit from online part requests and access to real-time part information. Your manufacturing group will avoid delays by having new part inventory on hand and ready for assembly. In fact, your entire company will profit from the improved communications that these tools provide.
All of these benefits are tied through the same system directly into the creation of a bill of materials. Engineering part requests get automatically transferred to the BOM, as well as the quantities and values used in the schematic. Reference designators are also sent to the BOM and then are automatically updated after design changes.
The creation of a bill of materials by BOM management tools replaces many different manual tasks with one automated system. Here is how that system can help you and your design process.
PCB BOM’s created as a living document can help assure your team’s success
The advantages of PCB BOM automatically created as a living document
The traditional method of manually creating a BOM, along with all of the edits and updates that go along with the process, are prone to error. There can be mistakes with data entry, design changes could be forgotten, or final verifications get missed. With automatically creating a BOM as a living document, these potential problems can be eliminated.
Parts that are added, changed, or modified on the schematic are automatically updated to the BOM in real-time without human interaction.
Component reference designators are automatically added to the BOM and are continually updated to reflect changes made in the layout.
Final verification to check for human data entry error is not required as the BOM has been updated automatically from the schematic and layout data.
Just as a faulty map can slow your trip down by getting you lost, a faulty BOM creation process can slow down your design and manufacturing processes with costly errors. With the BOM created as a living document within the BOM management tools, you will free yourself from these errors that can happen with a manually created document.
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PCB Design Tools for Electronics Design and DFM. Information for EDA Leaders.More Content by Altium Designer