The price of an assembled board is the sum of a bare board, the parts, the assembly work, the test, and the shipping. Some of these scale with the number of boards. Others are paid once per order, however many boards you buy. Knowing which is which tells you what to change when the price is too high.
Fixed costs and per-board costs
Paid once per order (set-up):
- Tooling for the bare board: film or imaging data, drill programs, the electrical test program.
- Machine programs for assembly, loading the feeders, a first-article check.
- A solder paste stencil, if one is needed.
- Test set-up, if you ask for a functional test.
- Engineering time to read the files.
Paid per board:
- Board area, layer count and the processes applied.
- Parts, including the cost of the parts bought but not used.
- Placement time, which depends on the number of parts and their type.
- Inspection and test time.
For one board, the set-up is the whole bill. For a hundred, it is spread thin. That is why the price per board drops steeply from one to ten and more slowly after that.
The shape is what matters here, not any value: the drawing has no numbers.
- The shaded part above the line is the set-up, paid once and shared by every board.
- The part under the line is the cost each board carries, however many you buy.
- At small quantities few boards share the set-up, so the price per board is high and falls fast.
- At larger quantities the curve nearly meets the line: more boards change the price per board only a little.
What moves the bare board price
| Choice | Effect |
|---|---|
| Board area | The factory builds on large panels; the cost follows the area of panel used, including the waste between boards |
| Layer count | Each pair of layers adds lamination, drilling and imaging steps. Going from two to four layers costs noticeably more; going from four to six, more again |
| Board thickness | Standard thickness is cheaper; unusual thickness may need special material |
| Copper weight | Heavy copper takes longer to etch and plate |
| Smallest track, gap and hole | Tighter than the standard process lowers yield, so costs more. Each factory has a standard class and a more demanding one |
| Hole count and size | Drilling is done one hole at a time; many small holes cost time. Very small holes break drills |
| Surface finish | Hot air leveling is cheap; immersion gold (ENIG) costs more; hard gold on edge connectors costs more again. See Surface finishes compared |
| Via treatments | Plugged or filled vias add steps. See Solder mask, silkscreen and via treatments |
| Controlled impedance | Needs a stack-up, extra tolerance control and test coupons |
| Special materials | High-Tg, metal core, high-frequency laminates cost more per area than standard FR-4. See PCB base materials |
| Solder mask colour | Green is the process default; other colours can cost more or have a different minimum feature |
| Outline | Cut-outs, slots and tight tolerances add routing time |
Board area includes the material between and round the boards. A panel of six boards shows it: everything in the panel is board material that is made and paid for, not only the boards.
- Rail: a strip of board material that the conveyor of the assembly machine holds.
- A board inside the panel.
- Break line: a V-cut groove or routed tabs, where the boards are separated after assembly.
- Tooling hole: an unplated hole that pins in fixtures use to hold the panel.
- Fiducial: a small copper mark that the machine cameras use to find the exact position.
What moves the assembly price
- Number of unique parts. Each unique part needs a feeder position loaded and checked.
- Number of placements. Machines place small parts very fast, so the count matters less than the variety. Large or odd-shaped parts are slower.
- Package type. Fine-pitch ICs, BGAs (ball grid arrays, whose connections are hidden under the part) and very small passives need more careful inspection, and X-ray for some.
- Sides. A board with parts on both sides passes through the line twice.
- Through-hole parts. These need an extra soldering step, by wave, selective soldering or by hand. See How boards are assembled.
- Test and programming. A functional test needs a fixture and a procedure, a programming step needs a file and a way to connect to the board. Both are set-up costs.
- Coating and cleaning. Extra steps after assembly.
Parts cost
For many boards the parts cost is the largest block. Three effects to know:
- Price breaks. Parts are cheaper per piece in larger quantities. A prototype run buys at the top of the price curve.
- Minimum order quantities. You may pay for a full reel to use ten parts. See Writing a BOM a factory can buy.
- The market. Prices and availability of some parts change from week to week; a quoted price for parts can be valid for a short time only.
Shipping and taxes
Shipping depends on the weight and size of the box and on how fast you want it. Import duty and tax are separate and depend on the country and on how the goods are classified. See Shipping and importing boards.
What to change first to save money
In rough order of effect:
- Check that every line of the BOM is needed and is the cheapest part that does the job. A different capacitor dielectric or a different package of the same chip can be a small saving per piece but a large one over a run.
- Reduce layers if the design allows it. Do this only if the routing is still clean; a cramped two-layer board is a worse board.
- Make the board smaller or panelise it well. See Panelisation and small boards.
- Use standard rules. Stay away from the smallest tracks, gaps and holes unless the design needs them.
- Use a standard finish and standard mask unless you have a reason.
- Order more of the same. If you know you need fifty, ordering fifty at once is cheaper than five orders of ten, because set-up is paid once.
- Avoid a rush. Express fabrication and priority parts both cost extra.
Do not trade away testing or inspection to save money on a board that will go into something you sell.
How this shows up when you order here
The price on screen follows the options you choose and is shown in US dollars; change one option and the price changes. An engineer confirms the price and the order before production, and may ask about a line the files do not settle. The options and limits in force are on the capabilities page. We do not state prices in articles, because they change with the options and with the parts market.