Understanding the cost factors involved in PCB assembly is crucial for effective project planning and budgeting. Among these factors, the number of layers is a critical consideration that significantly impacts overall costs.
Additionally, order volume directly influences the unit price of the initial batch. While PCB assembly cost is important, it is equally vital to optimize Bill of Materials (BOM) costs and consider Box Build requirements in electronics development.
To illustrate the cost variations, a PCBA manufacturer in Germany prices 30 two-layer boards sized at 80x90mm at US$339, whereas the same units with identical specifications can be procured for US$20 in China.
Table of Contents
FACTORS AFFECTING THE COST OF PCB ASSEMBLY
1- TYPE OF PRINTED CIRCUIT BOARD MATERIAL
The overall cost of a Printed Circuit board begins with the material you choose for your PCB; your choices are.
FR-4 laminate. FR stands for flame retardant and the 4 means fiberglass epoxy; the latter is great for bonding. This is the most common material for printed circuit boards.
CEM-1: CEM-1 is considered low grade in the printed circuit board assembly industry; it’s only used for single side printed circuit boards; it’s cheap but not as resilient as FR-4.
RF-35: This is a PTFE-based material that offers a combination of good performance and low costs for printed circuit boards for high-frequency applications.
Polyimide: This material is used for printed circuit boards that need to be flexible but at the same time need to be very strong and resistant to warping. The aerospace and military industry, where product quality is of the utmost concern, prefer polyimide for PCB manufacturing.
Remember, choosing the material for your PCB should not be based on the cost of the material and what the unit price will be, it should be based on what material offers the best performance for your product requirements.
2- PCB SIZE AND THE NUMBER OF LAYERS
The bigger the PCB the more material it requires, hence, the manufacturing costs rise; this is very logical.
The total PCB assembly cost will also be affected by the number of layers.
The PCB assembly cost is directly proportional to the number of layers it has. This is one of the most critical factors affecting PCB assembly costs.
If you’re a total beginner in electronics manufacturing you might think that to lower assembly costs you should aim for small one-layer printed circuit boards; well, that’s true, but it all depends on your devices’ requirements.
Sometimes 6, 8 and up to 12 layers will be necessary for your device to perform as expected.
Going from 1 layer to 2 layers can increase the unit price up to 40%. Also, consider that by adding more layers to your PCB you’ll be increasing the PCB assembly turnaround time as more steps will be necessary to complete the PCB manufacturing process.
3- SIZE OF BOARD HOLES
It shouldn’t come as a surprise that every detail on a PCB affects overall production costs, this includes the number of holes on a printed circuit board.
The more holes a PCB has the more lengthy and arduous the manufacturing process is, and therefore you get a higher assembly cost.
It’s not just about the number of them, it’s also about the size; if you need them to be extremely thin, then the total cost will go up as automated machinery will be needed to make them.
4-PRINTED CIRCUIT BOARD FINISH
The PCB assembly cost also has to cover the board finish; your choice of printed circuit board finish will depend on your device requirements or storing needs, perhaps you need PCBs with long shelf life.
While for many companies PCB surface finish is not a major PCB assembly cost factor, you still have to take it into account.
Read About: Plastic Injection Molding – The most costly part of an Electronics Product
TOP 5 PCB SURFACE FINISHES
- ENIG finish (Electroless Nickel Immersion Gold)
- HASL finish (Hot Air Solder Leveling)
- OSP finish (Organic Solderability Preservative)
- ISN finish (Immersion Finish)
- IAG finish (Immersion Silver)
5- COUNTRY LABOR COSTS FOR PCB ASSEMBLY
PCB assembly costs also involve labor costs; specialized and skilled professionals that know how to handle automated machinery and electric equipment are necessary for PCB assembly, especially when dealing with multilayer PCBs.
Setting up a PCB assembly operation in a country with very low labor costs such as Vietnam or India to save money in PCB assembly costs won’t work because these countries lack a skilled workforce.
You don’t want inexperienced hands dealing with your board. Also, in South Asia and Southeast Asia, you might run into a language barrier; communication delays will do nothing but increase your costs.
As of right now, 2021, China is the cheapest place – with a skilled workforce – to assemble boards.
Factories in western Europe or the US have a skilled workforce, but the assembly pricing is considerably higher.
Example
30 two-layer boards, 80x90mm in size will cost you US$ 339 from a PCBA manufacturer in Germany.
The same units with the same specifications will cost you US$20 in China.
Electronics NOT Made in China – Top 5 Alternatives
6- EXPECTED TURNAROUND TIME
PCB assembly costs will also fluctuate based on how fast you want them done and deliver to your geographical location.
If you want a quick turnaround it will be expensive. Unless you get them done in China where turnaround time is crazy fast.
But for those doing it outside China, well, if you tell a PCB manufacturer that you want your PCBs in 5 days, they’ll have to
- Put some existing orders on hold
- Work extra time and swap regular shipping for expedited shipping
7- PRINTED CIRCUIT BOARD ASSEMBLY AND ORDER VOLUME
For sure you’ve heard of economies of scale, the more you buy the cheaper the unit price; this economic phenomenon applies here too.
You’ll see the assembly cost for your PCBs decrease as you order greater quantities. This is especially true for the first run where setup charges, startup costs, and other one-time costs have to be pass onto the initial units’ cost.
But be careful with the lead time/turnaround time you ask for, if you make a large order with a super quick turnaround time, especially when you deal with overseas manufacturing, shipping costs can send your total cost through the roof.
8- TECHNOLOGY USED TO MOUNT COMPONENTS
A PCB assembled with SMT parts and components will be cheaper than one assembled with through-hole technology.
If your PCB requires ball grid arrays, then assembly pricing will be higher.
In summary, SMT ( surface mount technology) is more cost and time-efficient, if you’re looking to reduce costs then definitely go for this when designing the PCB.
Through-hole, technology makes the production process more arduous as holes have to be punctured in the PCB.
BGA requires the use of electrical pins, which increases assembly costs.
We can not tell you to stick to SMT components only for the sole purpose of reducing assembly cost; this will be dictated by the requirements of the product; sometimes you’ll have to THT electronic components and use ball grid arrays.
Try to force other components just to reduce costs and you might end up with unforeseen costs caused by product failures.
Read about PCB Assembly SMT, THT, and BGA
9- PACKAGING COSTS
Another of the various factors to affect assembly costs; electronic components come in different packaging and this influences the total assembly cost.
Components come in reels, tubes, trays, a cut tape with or without a leader, or loose in a bag. To get a low cost when buying components make sure you know how many units come in the package size.
A reel of passive components will probably have 10k units; cut tapes handle smaller unit size, but if you need, say, 1000 components, don’t assume you’ll get a cut tape with 1k units; you might get ten cut tapes with 100 units each.
The units in packages matter for inventory cost, and overall cost management.
Parts like BGAs have a higher assembly cost because these are fine pitched parts; you can not just use solder paste; they have electrical connections beneath them, which means it takes a higher source of accuracy to place these parts on a printed circuit board, this increases the assembly costs.
BGA also requires X-ray examination to check for voids and short circuits between the pins. This increases the assembly cost of these parts relative to the more generic lower costs packages like SMD.
10- CUSTOM SPECIFICATIONS
As you’ve seen by now, many factors affect assembly costs and they’re all directed by the specifics of your project, the more customization your PCB needs, the higher the actual price will be.
Say for example that you need your PCB to be waterproof because your device will be working underwater; this can be done, but it will raise costs.
HOW TO GET EXPERTS TO OPTIMIZE THE COST OF MY PCB FOR ASSEMBLY?
The best way to optimize the cost of your PCB is to make sure you put together a comprehensive bill of materials BOM.
Please do check out our BOM – Bill of Materials Cost Optimization in 3 Easy Steps article.
You’ll find this template, go to file and download Bill of Materials Template
You can use the PCB parts tab to list all the components you need with their respective cost and other information such as reference designators and manufacturer part numbers, then send it to us with the rest of the information of your project so we can give you a quote.
PCB ASSEMBLY COST CONCLUSION
You shouldn’t design a PCB to have the lowest cost possible; this is a recipe for disaster, instead, you should seek out experts to help to optimize the design of a PCB reaching its lowest cost possible but making sure it will perform as necessary to meet product’s requirements.
Remember that in the big picture of your electronic device project, PCBA is just part of the total cost, and prices while they might differ from supplier and country; they’re not the main cost driver.
BoM cost and box build see a much larger difference in cost.
Box Build Assembly Cost in Asia -Process, and PCBA
