The first time I prepared functional requirements for a web platform, I thought the document was massively complex. I forget the number of youtube tutorials I watched on preparing this document. Now that I have prepared several of these documents for a number of startups, I could probably write functional requirements in my sleep.
A bill of materials might also seem like a complex document if you have never prepared one in the past. When it comes to PCB design, you don’t have to create every deliverable by hand. Instead, there are a number of tools you can use to help you start preparing a bill of materials.
Preparing Your First BOM
A bill of materials contains important information that your manufacturer needs to fabricate, source, and assemble your next PCB successfully. A bill of materials for a PCB is delivered alongside other deliverables, including drill tables, Gerber files, CAD drafts of your board, panelized boards, and any other information your manufacturer needs to properly fabricate and assemble your device.
You’ll need to compile sourcing information, part numbers and quantities, suitable replacements (and price), and short descriptions into your bill of materials. This information can be obtained from a number of sources, including distributor databases, manufacturer websites, or even directly from your PCB design software.
If you’ve never prepared a bill of materials for a new electronic device or other piece of hardware, you’re probably tempted to start searching the internet for some kind of template that you can use in word processing software. These templates are out there and are certainly useful, but they carry some drawbacks when preparing a bill of materials.
A word processing template can be helpful as it gives you an idea of the information you need to include in your bill of materials. You’ll get to see what these documents look like and what a manufacturer expects to see. Unfortunately, word processing software cannot interface with your PCB design software. You’ll be stuck manually typing information from distributor websites or catalogs into your template. This creates plenty of room for omission or error.
Since a bill of materials is like a small database that compiles component specification and sourcing information, you might be tempted to use something like an Excel or Access database to start compiling your bill of materials. This software carries the same disadvantages as word processing templates in that it cannot interface directly with your design data. You’ll be stuck manually copying and pasting information between you component database or parts catalogs into your bill of materials.
This communication between design tools, your component libraries, and your bill of materials is critical for expediting this important process. Information in your component library must be imported into your bill of materials. Either you will have to look up information from your component libraries and copy it into your bill of materials manually, or you’ll need to use a tool that does this automatically.
Try using integrated software instead of typing up your BOM
Forget About Templates
Since templates are not the best choice to create a bill of materials, what is the enterprising designer to do? Instead of using templates, using a bill of materials generation tool that can interface directly with your design data is the better choice. Just like with templates, you can find a number of free or freemium generation tools online. Some of these are accessible via your browser, while others can be downloaded and run locally.
The danger with using free tools is that you have no guarantee that they can properly interface with your design data. Unless the company that built your design software also built the bill of materials generation tool, the generation tool will not be able to access design data, nor will it be able to update your bill of materials in the event of design changes. Only certain programs will be able to interface with your PCB design software, and they are not cheap.
Free tools that you download and install on your desktop may not be able to read your component libraries. These programs are built to work with specific file formats, and some library file formats are actually proprietary. The companies might not release details on the file format to anyone without a license agreement, so you cannot count on every free bill of materials tool to properly read your component libraries. You’re no better off than using a template.
Freemium tools may have the functionality you need, and they may even be able to read from your design and component libraries without any problems. But these programs love to masquerade as free programs, and the unwary user will quickly find that they are stuck between a rock and a paywall.
You’ll spend hours preparing your bill of materials with this program until it is perfect. Once you try to save it or export it as a finished document, the program gives you the bait-and-switch. Suddenly, you’ll find yourself in the infuriating situation where you’re blocked from saving your data unless you pull out your credit card.
PCB with green traces on black background
Integrating Design and Deliverable Tools
Rather than search for programs that match the component library format that is readable by your design software, the best deliverable generation tools integrate your component libraries and design features into a single interface. This design environment is ideal as all of these critical features are built using the same design engine, and you won’t have to worry about incompatibility among features.
Many PCB design software platforms claim to be unified as a single platform, but they still segregate features into separate programs. This forces you to repeatedly move data between programs manually, hampering your workflow and the creating potential for errors. Any time you make an update to your device, you’ll have to manually re-import your design data into your bill of materials tool.
The absolute best electronics design software not only integrates your design, data, and deliverable tools into a single environment, it also helps you properly source your components and manage component obsolescence. Component libraries that continuously update supplier information help ensure that you don’t break your manufacturing budget and avoid production delays.
PCB design software like Altium Designer includes all the tools you need to prepare a bill of materials for your device. The interface is powerful yet intuitive. The ActiveBOM tool is unified with your other design tools, and you won’t have to export data between programs or type up a bill of materials with word processing software. You can also export a bill of materials in many popular file formats.
To learn more about how Altium Designer can help you prepare bills of materials for any manufacturer, talk to an Altium expert today.
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