BOM &
Component Guide
Learn how a parts list supports your assembly project and explore sourcing options with our team.
You can share an existing BOM, spreadsheet or early component list. We’ll review it, discuss the parts you want to use and help clarify any missing information.
What is a BOM?
A bill of materials, or BOM, is the list of components used to build a product. For PCB assembly, it connects each part with reference designators such as R1, C5 or U2 on the board. It also helps purchasing identify the devices and quantities for the build.
Your CAD tool may export a BOM automatically, or you may already have a spreadsheet prepared by your designer. Both are useful starting points. Share the list you have and tell us which product or assembly version it describes.
Understanding the common BOM columns
| Field | How it helps | Example or explanation |
|---|---|---|
| Reference designator | Locates the part on the PCB | R1, R2 and R3 can share one BOM row |
| Manufacturer and MPN | Identifies the intended device | The manufacturer’s full part number, including relevant suffixes |
| Description and package | Makes the row easier to recognize | Resistance or capacitance, device type and footprint |
| Quantity per board | Shows how many are fitted to one assembly | Four references usually mean four fitted parts |
| Fitted / optional status | Describes the assembly version | Fitted, optional or DNP |
| Supply notes | Explains how the parts will be obtained | FLJ sourced, customer supplied or an alternative to discuss |
You do not need to reorganize your spreadsheet to match this table before contacting us. These explanations help you understand the fields; we can review your existing layout.
Why the complete part number is useful
A description such as “10 kΩ resistor” tells us the nominal value, but components with that value can differ in tolerance, power, package and other characteristics. A manufacturer part number gives purchasing a more specific device to discuss.
Distributor ordering codes are useful too, particularly when you have a preferred source. The manufacturer’s number and the distributor’s code serve different roles, so keeping both visible can make the sourcing conversation easier.
If a part number is missing or a device is difficult to obtain, we’ll ask about the intended part and discuss possible options. Alternatives can affect electrical performance, fit or firmware behavior, so the choice is reviewed with you.
Choose the sourcing arrangement that suits you
With turnkey assembly, FLJ handles component sourcing as part of the project. With consigned assembly, you provide the components. A mixed or partial-turnkey arrangement combines both approaches, for example when you supply a special IC and we source the other parts.
Tell us which arrangement you prefer. If you are undecided, share the BOM and we can discuss availability, the components you already hold and the practical options for your build.
A note against the relevant lines helps distinguish customer-supplied parts from the parts you would like us to source. We’ll work through the details with you during review.
How quantities relate to your build
Quantity per board and order quantity answer different questions. If four identical resistors are fitted to each board and you order 25 boards, the build uses 100 fitted resistors. This simple calculation is an example, not a material allowance.
Assembly preparation may involve additional material for setup or handling. Our team can discuss the allowance for the actual components and packaging, so you do not need to guess it from a generic table.
If your product has several variants, tell us which one you would like to build. We can help distinguish fitted parts, optional parts and differences between the lists.
An optional BOM example
This CSV shows common fields and an illustrative row. Use it if helpful, or send the BOM you already use.
Sending components you already have
Start by telling us which parts you plan to supply and how they are packaged — reels, cut tape, trays or tubes. We can then discuss receiving details, quantities and how they fit into the assembly plan.
Original manufacturer or distributor labels are helpful because they connect the physical packages with the BOM. A short packing list can also help identify the parts and quantities in the shipment.
For moisture-sensitive or ESD-sensitive parts, the device’s handling information helps us discuss appropriate storage and preparation. If packaging has been opened, let us know so the team can review the condition with you.
We can also discuss partial deliveries, shortages and the handling of unused parts as part of your order.
Your questions, answered
My BOM has some missing part numbers. Can I send it?
Yes. Share the list and point out any choices still being developed. We can review it and discuss the information needed to identify the parts for sourcing.
Can I supply some components and have you source the rest?
Yes. Tell us which parts you already hold. We can discuss a mixed sourcing arrangement for the remaining lines.
Do I have to use your BOM template?
No. The template is a helpful example. Your existing spreadsheet or CAD-exported BOM is a useful starting point.
What if a part is unavailable?
We can discuss availability, timing and potential alternatives with you. Any proposed substitution is reviewed against the needs of your design before it is used.
Share your parts list
Send the BOM or component list you have and tell us whether you would like sourcing, assembly or both. Our team will help clarify the parts and supply arrangements.
Email [email protected] with your files or question. Our team will review the information and follow up with you about the next step.