PCB Assembly Cost Driver Analysis and Price Calculation

PCB assembly cost is a factor that all engineers must be aware of before electronic projects start, as it will help in planning the cost and profit control of the entire project. From the perspective of a turnkey PCBA supplier like FS Technology, it is not only our responsibility and obligation to help customers understand the calculation method of assembly price, but to also shorten the quotation cycle. This ends up being mutually beneficial, no matter from which point of view.

During the electronic project process, most engineers calculate the cost of PCBA through a PCB assembly cost calculator, and will typically choose the PCB assembly company that they think is suitable through price comparison. However, there are flaws in this method. For PCB assembly projects, the generation of these costs mainly depends on the services provided by the PCBA factory. This article by FS Technology will help you understand the calculation method of PCB assembly price in the form of text, and should help you find PCBA suppliers based on price.

Factors Affecting PCB Assembly Cost

When choosing turnkey PCBA service, the typical cost drivers for PCB assembly include PCB bare board manufacturing cost + electronic component procurement expenditure + SMT and DIP assembly cost + PCBA testing fee + packaging + other service fees (Fast Turnaround PCB Assembly, Conformal Coating, Golden Finger and more).

PCB bare board manufacturing cost

Circuit board material selection

This is quite a universal concept in almost all industries, including the textile industry, as even if you buy the same style of clothes but they are made of different materials for example, the price will not the same. With FS Technology’s PCB material selection, the prices of our acceptable circuit board types can be ranked according to price in this order (highest to lowest): Ceramic PCB > Aluminum PCB > Rogers PCB > FR4 PCB> Cem-3 PCB.

PCB fabrication process costs

Different PCB production processes will induce different costs. For example, gold-plated plates, tin-sprayed plates, gong (milling) plates and beer (punching) plates, which are used for making shapes, will incur a wide array of costs. In addition, other processes like using silk-screen lines or dry film lines, etc. may add to that total cost.

Difficulty in manufacturing circuit boards

Even though the materials used and the PCB manufacturing steps are the same, the difficulty of the PCB itself will have an effect on costs. For example, if there are 1000 holes that need to be drilled on two kinds of circuit boards, and the hole diameter of one board is greater than 0.6 mm whereas the hole diameter of the other board is less than 0.6 mm, there will be an obvious difference in drilling prices. If the two kinds of circuit boards are the same, but the line width and line spacing are different between the two where one is greater than 0.2 mm, and the other is less than 0.2 mm, this will also cause varying production prices. Due to the higher scrap rates involved with higher difficult boards, the cost will inevitably increase.

Layers and Dimensions

It is very logical that the size and number of layers of the PCB affects the amount of material and the difficulty of manufacturing the PCB. The unit price is about 40% higher from 1 to 2 layers. In addition, the cost of your entire project should not just involve the price, but also the longer lead time. The price of the PCBA board is not very affected by the size of the board. The following images below are a comparison of two circuit boards: the left image is a smaller but more expensive main control board and the right picture is a larger but cheaper power board.

Customer’s special request

The level of customer requirements will directly affect the yield of a PCB factory. For example, a board fabricated according to IPC-a-600e, Class 1 requires a 98% pass rate, but according to Class 3 requirements, it may only have a 90% pass rate, resulting in different costs for the board factory.

Further reading: A must-read guide for the PCBA industry—IPC standards

Lead Time

It goes without saying that time is money. When we receive your order, we will schedule it immediately and estimate how long it will take from production to delivery. If your item is very urgent and your requirements include receiving the goods within a short period of time, then you may need to pay some expedited fees. This is because we will need to put some existing orders on hold and invest more manpower and time to fulfill your order. This expedited fee is partly used to pay workers for overtime and partly to compensate for orders on hold.

PCBA component procurement cost

Electronic components are the main cost in PCBA processing, which involves the PCB assembly cost per component as well as the procurement cost of individual components. FS Technology purchases components according to a project’s BOM (Bill of Materials). That is to say, the cost involved with this aspect is mainly dependent on your project, and if your project requires components with high TG (thermal rating or low dielectric constant), then more expenditure will be required. Fortunately, FS Technology advocates a win-win situation and has a team of specialist designers to help. When we receive your BOM purchase form, we will advise you on replacement components to help save costs on your project (under the premise that the quality is not affected).

In the values of FS Technology, quality is always more important than price. The quality of components greatly affects the performance and service life of PCBA boards, especially in ICs (integrated circuits). In addition, high-quality components are a prerequisite to support complex circuits. In our past services, we have encountered many customers who cannot differentiate between price and quality, but we have always advocated that quality should be the first priority.

Assembly technology affects PCBA cost

THT and SMT assembly costs are calculated by the number of pad points on a PCB as the greater the number of pad points on a board, the higher the price. Another factor that needs to be considered is that the price of THT is higher than that of SMT assembly. This means that if you want to save project overhead, you can use SMT technology instead of THT.

SMT Assembly:

SMT is the most mainstream assembly technology at present and allows for more components to be mounted on the same circuit board. It can be fully automated in terms of component placement, making its price cheaper. However, SMT assembly can result in the need for additional through-hole drilling in order to mount surface mount devices (SMD components), which can lead to soaring costs.

THT Assembly:

THT is a traditional plug-in technology, with the development and evolution of technology, THT has been gradually replaced by SMT due to the pursuit of small-volume equipment and automated production. If these two technical means are isolated, the price of Through hole PCB assembly is typically higher as it can only be installed manually, and large-scale automated production cannot be realized (according to the strength of the processing plant as it is not absolute). Therefore, THT assembly requires more manpower and labour costs to be invested.

Stencil cost

Typical PCB assembly cost is also dependent on the stencil used. A stencil is required to print solder paste on the PCB pads during the PCB assembly process and is a basic tool used in PCB assembly. This is usually a one-time cost as long as the manufacturing files do not have any particular requirements/changes.

PCB assembly inspection cost

PCBA testing accompanies the PCB production and assembly process and is an important step in ensuring product quality. In order to provide high-quality circuit boards, there is no charge for general testing services, but if you need additional testing services, you will need to pay a fee. This cost depends on the complexity of the test process and test time. In order to make it smoother for you to order PCBA services, FS Technology has organised the following about PCB assembly inspection fees for you:

Visual inspection, including MVI, AOI and AXI, are all free of charge.
ICT tests are generally free of charge, including flying probe tests and bed of needles tests. Flying probe testing is commonly used for small batches of samples and is relatively slow but if you need to do high-volume testing, then you need to do a bed of needles testing, which may incur a portion of the testing cost.
For the detection of design errors, you need to do IC programming and functional testing. Depending on the test time and difficulty, you will need to pay a test service fee for this.

Conformal coating cost

There are two methods that are used for conformal coating: a conformal coating sprayer and manual coating. The conformal coating spraying machine mainly generates the man-hours and material cost of spraying whereas manual coating predominantly involves labour costs and consumables. Hence, if the customers’ PCBA has conformal coating requirements, there will be a conformal coating cost charged, but for the prototype order of the first cooperation, FS Technology provides a free conformal coating service.

Order quantity

Regardless of the industry, there is an economic effect of mass production on making products cheaper, faster and of higher quality (this is not a linear relationship).

The reason for this phenomenon is due to the finished cost of PCBA being divided into variable costs (material and assembly costs) and fixed costs (startup cost and programming overhead). Variable costs increase as the number of PCBAs increases, but the unit price allocated to each PCBA does not change. The fixed cost itself is not affected in any way, but as the production volume increases, the cost allocated to each PCBA becomes lower.

In the long run, increasing the number of printed circuit boards can save costs for companies by avoiding unnecessary one-time costs.

Package cost

Every customer’s PCBA size and requirements are different, so the packaging of each product always differs. Usually, the manufacturer will be responsible for packing each product well in preparation for shipment, but if customers have special packaging requirements and custom packages are needed, a package cost will be charged.

Suggestions for Reducing PCBA Assembly Costs

Optimized Design: Working with experienced engineers and designers can help optimize the layout of the PCB and components, reducing the complexity of the assembly process. FS Technology recommends removing blind/buried vias or vias on SMD component pads under the premise of quality assurance.
Reduce the number of components used: This can result in cost savings in three areas: procurement, assembly, and design. If necessary, consider using common components that can be used across multiple designs.
Component Substitutions: When the prices of board components change or increase due to issues such as component shortages, considering alternative components that are functionally equivalent but less expensive can result in cost savings. However, it is crucial to ensure that these alternative components meet the necessary performance and quality standards.
PCB type: Define your project requirements before manufacturing. Choosing the right PCB type according to the requirements of the project is key to reducing the cost of the project.
Choose turnkey PCBA service: Turnkey project is one of the key points to simplify the project process and save assembly costs. For turnkey PCBA assembly customers, our design team will evaluate the bill of materials after you submit the BOM file. If we find a component that can be replaced with a lower price, we will communicate with you in a timely manner.
Mass production: If it is a new project or a first-time supplier, FS Technology recommends you make a PCBA prototype. These samples help you to check whether the supplier is qualified to fulfill your order.

Conclusion

In conclusion, PCBA costs are made up of many factors. Any of these said factors will cause varying PCBA costs, so customers should choose a supplier according to their own requirements. If you recognize the capabilities of FS Technology, please contact us via email as we have a 24-hour one-to-one service, and we will provide you with FS Technology’s PCB price list. That wraps up this article and be sure to check out more of FS Technologies’ PCBA Blog.