Many customers would not know what affect a PCB cost and how it works, today let's review it in detail and then you know--how to save cost at designing stage.
While a Chinese PCB manufacturer receive a inquiry from client, the sales will forward the Gerber file along with board specification to engineers. Engineer will open Gerber file and make an evaluation for the PCB and then reply to sales/quotation team.
Engineering evaluation sample
Sales will check the evaluation result and make quotation accordingly.
Basic Factors that affect pricing
Layers: The more layers, the higher price.
Surface Finishing: HASL, HASL LF, ENIG, Immersion Silver, etc. Price varies on choice.
Board Thickness: The thicker, the higher cost.
Material: For standard FR4, the higher tg value, the higher cost. For PTFE, MC PCB, varies on choice. Even for FR4, if brand and model is required in specific, price will change.
Copper Weight (oz): the heavier, the higher price.
Order Area Size(m2): The more, the cheaper. Area=length*width/purchasing quantity.
So above are basic factors, usually a standard regular PCB is with the following specifications:
FR4 Tg135, 1.6mm board thickness, 1/1oz copper weight, HASL LF, 2 layers, Min. Line space/Line.width: 4/4mil, Minimum Drill 0.2mm, IPC CLASS II
But PCBs are not that normal in most of the cases, so let's review extra factors that affect on pricing too:
Carbon Print: require extra cost
Peelable Mask: require extra cost
PTH Copper Weight over 25um
Small PCB: if the board is too small, will require extra routing work.
Impedance Control: often along with PTFE laminate
Automotive Grade: higher quality grade require higher cost
IPC Class III: higher quality grade require higher cost
Blind/Buried Via: require extra cost
Gold Finger: require extra cost
Edge Platting: require extra cost
Half Hole Board: require extra cost
Thick hard Gold: require extra cost
Test hole quantity: higher fixture cost
As a PCB manufacturer, the standard price matrix are in USD/M2, lets take a sample:
A new inquiry with the following specifications
Let's compare with standard specification, the differences are: 4 layers, Peelable Mask and Automotive Grade.
Then check the purchasing quantity, for example: 2K pcs. The total area(m2) is: 45*125/1000000*2000=11.25m2
Sales look up in price matrix and found, for example, 130 USD/M2, with additional terms: peelable mask add $10/m2 and automotive grade add 10% of price.
So the price for m2 is 130*10%+10=$153/m2
The order total amount is, ignore test cost, 153*45*125/1000000*2000=$1721.25, and the unit price is $1721.25/2000=$0.86/pcs
Yes, this is how your PCB unit price are calculated.
Let's sum up the steps:
Calculate the overall order square(m2)
Check if specification is standard or not, if not, add extra cost
Calculate the overall order amount
Divide to unit PCB cost
Concerning every PCB manufacturer has its own sales strategy, they have different price sections and cost add terms, but generally every PCB factories have the same core system about quotation.
And this is for rigid PCB only, for FPC, ceramic PCB the calculation has some differences.