Bill of materials
What is the bill of materials and its different markings?
A bill of material is a list of all the components, sub components, parts, assemblies and other equipment needed to manufacture the end product. Many industries need to generate BOM for expert analysis before manufacturing the final product. So a BOM can be of 3 different types.
- Engineering BOM
- Sales BOM
- Manufacturing BOM
The components in all these can change based on the analysis. During engineering BOM is done during development stages in which all the components needed are included in an excel sheet. Sales BOM is when purchasers are buying the components and they can make slight changes to the BOM depending on the availability of the components. Manufacturing BOM is the final excel sheet which has all the optimisation done to reduce the cost of the final product and also to redesign the engineering work if a particular component has shortage of supply. So care must be taken by designers to make sure that the components have steady supply and that they will not have an end of supply in near future while also considering the cost.
Many industries generate a BOM file for every new product. These can be automobiles, technology development, pcb manufacturing, construction, warehouse, and many more. There are important fields in the BOM. Some of the fields indicated that DNP which means the sales person need not buy such components from the BOM. and some are TP there are also the components that need not be purchased. Some rows indicate alternate components which means the seller has a choice to either components1 if it is not available for some reason then they can buy component2 since both have the same footprint and serve the same purpose of the job.
Most of the designers use certain tools to generate this BOM file. Many cad designing, pcb designing tools like
- Orcad.
- Altium Designer.
- Autodesk EAGLE.
- KiCad EDA.
- SolidWorks PCB.
- OrCAD Capture.
- ExpressPCB Plus.
- DipTrace.
How to generate a BOM?
Many tools have different options to generate a BOM file. A BOM should include at least these details.
- Part number
- Manufacturer name
- Description
- Quantity
- Procurement type
- Flexibility indicator
- Alternate parts
- BOM level
- Supporting files
- Reference designator
- Package type
- Placement method
- Board layer
- Phase
- Comments and notes
You can create one from the menu using the following options in most of the tools but some tools have a different option based on native language and convenience.
Manufacturing -> Master Data -> Bill of Materials -> Create
Sample bill of materials.
Most BOM contains per row for a component these values so it will be easy to analyse and mark if some of the components have a shortage or supply or something else.
- Reference
- Part Number
- Manufacturer
- Description
- Pop Option
A sample BOM table is shown below and can vary depending on the tool used to generate the file.
| Item | Quantity | Reference | Part | PCB Footprint |
| 1 | 1 | CN1 | 1775838-2 | sata_pci_cn |
| 2 | 26 | C1,C2,C4,C7,C8,C9,C10,C11,C12,C13, | 10uF,10V | 805 |
| 3 | 110 | C3,C20,C28,C31,C33,C35,C36,C37, C42,C43,C44,C45,C46,C47,C48,C49, C52,C53,C54,C56,C57,C58,C59,C60, C64,C65,C66,C67,C68,C69,C70,C71, C74,C75,C76,C78,C79,C80,C81,C82, | 0.1uF,16V | 402 |
| 4 | 5 | C16,C17,C18,C24,C125 | 2.2uF,6.3V | 402 |
| 5 | 2 | C19,C136 | 470pF,6.3V | 402 |
| 6 | 6 | C21,C22,C25,C26,C185,C186 | 18pF,50V | 402 |
| 7 | 2 | C32,C123 | 0.001uf,16V | 402 |
| 8 | 12 | C34,C178,C180,C182,C228,C229, | 100uF,6.3V | C_elec_6 |
| 9 | 6 | C89,C90,C91,C104,C106,C134 | 1uF,10V | 402 |
| 10 | 1 | C141 | 0.022uF,10V | 402 |
| 11 | 2 | C142,C143 | 30pF,50V | 402 |
| 12 | 7 | C175,C188,C189,C193,C194,C195, | 4.7uF,6.3V | 402 |
| 13 | 1 | C212 | 0.01uF | 402 |
| 14 | 2 | C215,C218 | 22uF | 805 |
| 15 | 1 | C217 | 47pF | 402 |
| 16 | 4 | C222,C223,C224,C225 | 15pF | 402 |
| 17 | 1 | C226 | 2.2nF | 402 |
| 18 | 4 | C230,C231,C232,C233 | 12pF | 402 |
| 19 | 1 | C238 | 0.22uF | 402 |
| 20 | 1 | D3 | 1N4148 | DO35 |
| 21 | 1 | D7 | CDSOT23-SM712 | SOT-23-3 |
| 22 | 9 | FB1,FB2,FB3,FB4,FB5,FB6,FB7, | 150OHM800mA | FB_0805 |
| 23 | 1 | FB9 | 1uH | L2520 |
| 24 | 1 | FB10 | 0.1 Ohm | FB_0805 |
The second part of the same BOM file is as shown below.
| Description | Manufacturer | Manufacturer PN | DNI |
| CONN PCI EXP MINI FEMALE 52POS | TE Connectivity AMP Connectors | 1775838-2 | |
| CAP CER 10UF 16V X5R 0805 | Murata Electronics North America | GRM21BR61C106KE15L | |
| CAP CER 0.1UF 16V X7R 0402 | Murata Electronics North America | GRM155R71C104KA88J | |
| CAP CER 2.2UF 6.3V X5R 0402 | TDK | C1005X5R0J225K050BC | |
| CAP CER 470PF 50V X7R 0402 | Yageo | CC0402KRX7R9BB471 | |
| CAP CER 18PF 50V C0G 0402 | TDK | C1005C0G1H180J050BA | |
| CAP CER 1000PF 16V X7R 0402 | Yageo | CC0402KRX7R7BB102 | |
| CAP ALUM POLY 100UF 20% 6.3V SMD | Panasonic Electronic Components | 6SVP100M | |
| CAP CER 1UF 6.3V X5R 0402 | TDK | C1005X5R0J105K050BB | |
| CAP CER 0.022UF 10V X7R 0402 | Tayo Yuden | LMK105B7223KV-F | |
| CAP CER 30PF 50V NP0 0402 | Kemet | C0402C300J5GACTU | |
| CAP CER 4.7UF 6.3V 20% X5R 0402 | MURATA | GRM155R60J475ME47D | |
| CAP CER 10000PF 16V X7R 0402 | Murata Electronics North America | GRM155R71C103KA01D | |
| CAP CER 22UF 16V X6S 0805 | TDK Corporation | C2012X6S1C226M125AC | |
| CAP CER 47PF 50V NP0 0402 | TDK Corporation | CGA2B2NP01H470J050BA | |
| CAP CER 15PF 50V NP0 0402 | Johanson Technology Inc. | 500R07S150GV4T | DNI |
| CAP CER 2200PF 50V X7R 0402 | AVX Corporation | 04025C222KAT2A | |
| DNI | |||
| CAP CER 0.22UF 50V X5R 0402 | Taiyo Yuden | UMK105BJ224KV-F | |
| DIODE GEN PURP 100V 200MA DO35 | ON Semiconductor | 1N4148 | |
| TVS DIODE 7VWM/12VWM SOT23 | Bourns Inc. | CDSOT23-SM712 | |
| FERRITE 800MA 150 OHM 0805 SMD | Steward | LI0805H151R-10 | |
| FIXED IND 1UH 4.3A 42 MOHM SMD | Murata Electronics North America | DFE252012P-1R0M=P2 | |
| RES SMD 0.1 OHM 5% 1/8W 0805 | CTS Resistor Products | 73L3R10J | |
| CONN HEADER .100 SINGL R/A 6POS | Sullins Connector Solutions | PEC06SBAN |