Table of Contents

• 1. How much does PCB Assembly Cost?
• 2. How To Save Money On PCB Assembly?
• 3. Why is PCB Assembly so Expensive?
• 4. PCB Assembly Process
• 5. PCB Assembly Methods

How much does PCB Assembly Cost?

PCB assembly costs include various costs, including labor cost, turnaround time, technology, PCB quality, and parts packaging. Some cost calculators can calculate the manufacturing of PCB, including the operation cost. The unit cost of PCB depends on the number of units produced. It also depends on the type of PCB, including 5G PCB, High-Density Interconnect PCB(HDI), Flexible PCB, etc. The PCB manufacturing cost is affected by various factors, which are as follows:

Labor Cost

The labor cost is one of the impacting factors in the price of PCB manufacturing. The labor cost depends on the geographical location. Besides, the manufacturing of PCB includes a skilled human workforce and automated machines. Some overseas manufacturing could increase the cost because of shipping and communication delays. 

Turnaround Time

The expected turnaround time is one of the common factors that affect the assembly cost of PCB. It can call the turnaround time required for completing the manufacturing process and satisfying the request of the customers. The shorter the turnaround time, the more the cost for PCB assembly. It can drive up to 33%, which is ⅓ of the cost of the PCB assembly.

Quantity

The more the quantity, the less the manufacturing cost because of economies of scale. In this process, the unit prices of each PCB drop significantly; thus, the firm can save money in the long run. It happens as the firm can control various factors that affect the assembly cost, like startup programming and cost and initial unit cost. 

Technology

PCB assembly uses two types of technology; Through-Hole Technology and Surface Mount Technology. In the SMT process, the setup cost is lower than heavy automation. However, SMT is required in through-hole drilling. 

Parts Packaging

Some of the sensitive and complex parts require special packaging. This increase the labor cost as the proper assembly is the goal. If we see the BGAs, and electric equipment, it requires various efforts and time for packaging as they require the electrical sources. They should also go through an X-ray examination to test the short circuit. 

PCB Size

The other crucial factor that affects the cost of PCB includes the size of PCB and the panel utilization. The number of circuits can determine the board size required. On the other hand, the component's amount of space can also affect the price. Thus, the dimensions of the PCB design determine the overall costs of PCB. 

Material Choice

The material used in the PCB board affects the cost of the assembly process. For example, lamination in standard PCBs uses FR4 materials. The operations that require higher frequency require higher-grade materials. Thus, the materials used in microwaves or aerospace and fuel industries can cost more than that of handheld devices. 

Number of Layers

The number of layers involved in PCB is one of the other factors that determine the price of the PCB. The two-layered PCB board costs lesser compared to 3 and high-layer boards. Since the thick layer board requires more work in manufacturing. Besides, the pricing issue is also affected by board size and the materials used. Besides, assembling the multi-layer board requires various steps, and there is a high chance of defects. Thus to counter this issue, PCB makers provide extra efforts. However, it will ultimately increase the cost of the assembly. 

Size of Hole

The hole size of the PCB board is also one factor that can affect the cost of PCB production. The required number of holes in the board and the thickness of layers and material types to be drilled also determine the price. For example, the PCB board with ten or more layers requires more time to drill. Also, if the materials were strong, the drilling process would have been more complex, impacting the price of the PCB. 

The super thin hole requires a unique tool to produce. This ultimately increases the price of the production. 

PCB Finish

The cost of finishing is also the factor affecting the PCB's cost. The finishes that have higher grade offers a longer shield life. This adds to the overall cost of the productions. HASL is one of the low-cost and standard surface treatments. It offers good solderability. Every surface treatment offers its own features. The top five PCB surface finish includes:

• ENIG finish (Electroless Nickel Immersion Gold): Good Solderability, the contact surface, and AI wire bondable
• HASL finish (Hot Air Solder Leveling): Good Solderability
• OSP finish (Organic Solderability Preservative): Good Solderability
• ISN finish (Immersion Finish): Good Solderability
• IAG finish (Immersion Silver): Good Solderability and AI wire bondable
• Besides, the number of layers determines the finish impacting PCB production.

How To Save Money On PCB Assembly?

PCB Design

Proper designing of PCB helps in reducing the cost of PCB assembly. The design factors affecting the price of PCBs include:

• 1. Via Technology
• 2. Layer Count
• 3. Surface Finish Type
• 4. Size and Shape

When manufacturing the PCB, you can redesign each of the elements mentioned above to reduce the cost of the PCB. 

Comprehensive Bill of Materials

It should create the bill of materials(BOM) to list all the components in the PCB board. The PCB design checklist can determine all the required BOM, including footprints, parts numbers, reference designators, and assemblers. BOM should also include the alternative components or parts for each used component on the board.

Order Time & Quantity

Order and volume are critical factors for price determinations. According to the concept of economy of scale, the higher the order volume, the less the unit price. Therefore, you should select the manufacturer based on your order size and the manufacturer's turnaround time. 

Inspection & Testing

The cost reduction should not compromise the quality of the PCB board. Thus the testing and inspection of the product is a must before sending the product to market. The temperature of the traces on board requires proper monitoring. It could be in both internal and external layers. Proper inspection and ensuring the circuit is adaptive to changing temperatures can minimize the long-term risk.

Why is PCB Assembly so Expensive?

The cost of PCB design and manufacturing is determined by various factors like intricacy of design, elements types, and project effectiveness. In addition, the complexity and nature of the circuit also determine the assembly cost of PCB. In contrast, the final price is affected by the quality of the PCB design. 

PCB assembly is expensive due to leadless components and precise pitching. It is because it requires testing methodologies, including a unique assembly process. The cost of fundamental ingredients leads to the higher cost of the PCB assembly. The production and assembly of printed circuit boards (PCBs) to meet the needs of various sectors is done at a high technology level. PCB assembly expenses, therefore, depend on factors directly related to companies, products, and assembly methods.

Besides, the PCB assembly option also factors in the cost of the PCB in two ways:

• 1. Costlier material 
• 2. As a result of production irregularities, every assembly procedure requires some retesting.
• 3. The assembly method also impacts the performance and fabrication cost of PCB.

Cost Comparision between SMT and THT

Some of the fundamental difference between these two assembly methods includes:

• 1. The drilling process in THT adds the extra cost of assembling. Thus the SMT is cost efficient than THT.
• 2. THT components contain the lead, while SMT doesn't. This shows the environmental nature of SMD compared to THT.
• 3. SMT uses automation technology in soldering. The use of automation reduces the assembly cost of PCB. While in THT, a manual process is used.
• 4. SMT allows the compact design size. So, SMT helps to save space which is a better feature in terms of high-frequency and high-density PCB design.

PCB materials for PCB assembly cost

PCB material and components can be considered the most significant area of PCB costing. For example, FR4 leads to a higher cost and is standard material. At the same time, some other materials like Polyimide Laminate cost more which is required for high-grade materials.

Some of the factors that affect the material selection for PCB manufacturing include:

Thermal Property

The need and requirement of thermal properties of materials vary based on PCB types and applications. The higher the thermal management cost and the more the material cost.

Heat Transfer Ability

The heat Consumption ability of the materials requires proper checking. The important thing is how much the material can withstand the heat environment.

Signaling Ability

For signaling, ability checking is required for specific applications. The materials should make sure that each PCB components pass the signaling ability.

Mechanical Property

The selected material should withstand the physical stress in a specific environment.

Customer Specification on PCB Assembly Cost

Customers want to have their custom specifications while manufacturing the PCB circuit board. This customization significantly includes the cost of PCB assembly.

The more customer customization, the more will be the cost of the PCB assembly. Standard customization includes trace dimensions, thickness, layer count, conformal and metallic coatings, etc. All of these customization requirements can significantly increase the assembly cost of PCB. Thus, the customer specification needs to be handled with close attention. 

Finding the alternative or the middle way is beneficial so that customization doesn't cross the budget limit. One way to optimize includes managing the components sourcing for customization. Try to find a way to trace designing, soldering, and layering for cost minimization. 

PCB Assembly Process

Before starting the PCB assembly process, you should have a proper DFM(design for manufacturing) checking.

• 1. It must take a few primary steps before the PCB assembly process begins. Printed circuit board makers can use this as a DFM check to analyze a PCB design's performance.
• 2. Typically, assembly process businesses require PCB design files, along with any design comments or unique specifications. This process is known as the DFM check. PCB assembly companies use this method to inspect PCB files for flaws that may affect the PCB's functionality.
• 3. DFM checks the PCB design parameters. The process includes searching for any absent, harmful, and repetitive functionalities. Any of these errors could affect the final functionality of the project. 
• 4. DFM inspections reduce production costs. In this way, these inspections scrapped the fewer panels. A free DFM assessment includes every PCB Cart project order.

Steps in PCB assembly process

Groundwork

A Pcb assembly proceeds by checking the layout document for possible errors. This layout examination ensures to address any concerns well in advance by ensuring constructability tests. In addition, the design aspects evaluate if they could cause problems in manufacturing.

Solder Paste Printing

In the initial stage of the PCB assembly process, it requires solder paste jet printing. As a result of heat, solder paste bonds metal solder balls together with a particular chemical. In this case, the fluid is dispersed using only a solder paste jet printer at a rate of 300 bits per second. With this technology, you can quickly create a better model, minimize waste, and change boards. Additionally, you won't need to change boards before installing them.

Solder masks will only apply to the mounting areas after administration. After that, the machine uniformly pastes the PCB solder paste. The final remaining is a printed circuit board.

Pick and Place Process

Pick and place machines to connect the solder to predefined spots on the assembled PCB. Finally, the mechanical arm can help move the surface-mounted parts in the printed circuit board. This pick and place machine could attach the surface mount elements to their specific places. 

PCB Reflow Soldering

After installing the surface mount components in the circuit board, the solder should be warm and used. Solder paste should be warmed in a reflow oven by a conveyor that transports the printed circuit board. There will be independent solder stenciling and reflow soldering on the two sides of this double-printed circuit board assembly.

Quality Control

After sticking the surface mounting components, the reflow process completes. Then the final PCB board is checked for operation. Reflow stage component placement errors often result in poor connectivity or even no connectivity. In some circuits, displaced elements can interconnect parts that shouldn't, resulting in flashes. This type of fault and misalignment can be detected by surface mount technology.

The popular inspection method includes:

Manual Inspection

Manual inspection is a common and traditional method of examining the PCB assembly in spite of emerging automation trends. 

Visual inspection by design is an effective way to ensure PCB integrity following reflow for small volumes. The complexity and error of this procedure increase as the number of examined boards increases. Examining these simple sections for longer than an hour can cause optical fatigue, resulting in a less precise result.

Automatic Optical Inspection

Automation optical inspection seems best when it comes to the higher quantities of PCB inspections. This process uses a variety of optical lenses for viewing PCBs. Moreover, various AOI can help detect the lesser solder joints as various solder joints show or reflect the various light ways. Moreover, the AOI or automatic optical inspection carried out this process at a rapid rate. Thus it could handle the large number of assembled PCBs within a short period. 

X-ray Examination

X-ray Examination is another method of inspection for the PCB boards that are more layered. In order to spot potential issues, an observer can see through layers using an X-ray. Certification and rebuilding or the discarded process will overtake the defective boards. The PCB assembly services make this decision.

Final Examination 

The completion of the soldered stage of the PCB assembly process helps to test the proper functioning of the PCB board. This is called functional testing. This test simulates the PCB's regular operation by running it throughout its length. During this test, testers examine the electronic engineering of the PCB by sending power and simulated signals across it. 

PCB is termed as failed if any properties of PCB fail to work. Particular PCB testing includes; signal output, excessive fluctuation, voltage, and signal power output. Then, depending on the firm's criteria, the recycling process of PCB is carried out.

How much time does it take to manufacture your PCB?

Various steps are there in manufacturing the PCB product. The time required to make your PCB board depends on the following factors: 

• 1. Initially, the PCB manufacturer reviews and checks your design, ensuring the design layout is correct. This process can take a minimum of 2 days for simple design, while for complex design, this could take more than two days.
• 2. Manufacturers check your PCB design against the components you have supplied. They can usually check 500 parts in one day, but it depends on your components.
• 3. Sophisticated machine prints the PCB board. It includes several operations like drilling, cutting, and punching. Depending on the complexity of your design and the individual components, this process can take an hour or more.
• 4. Then the manufacturer outsources the board for printing to European or Asian shops, which could apply a solder mask and paste to each terminal of the PCB. This could take three days, depending on the track numbers and the number of PCBs that the manufacturer produces. 
• 5. The final step includes the use of robust antistatic packaging materials for packing the boards. The process takes less than 24 hours. 

PCB Assembly Methods

PCB assembly circuit boards include various methods and processes. Manufacturing the PCB includes the copper clad with conductive ink. Then the PCB is placed in the machine with multiple heads and squirts the conductive ink or the hot solder paste on the board. Finally, components placed on each pad are soldered properly. Again, machines perform this process with multiple heads replacing the components. In case of any defects, the solder joints will be reflow. 

Some of the standard methods of PCB assembly include:

Automatic Insertion Machines(AIM)

This AIM machine places the components using the assembly line or robotic arm. One of the advanced technologies, machine vision, is used for correctly placing the components. The complex machines used the calculator device that provides the position of components. These machines include four arms, two on each side. This helps in faster and more efficient assembly. Machines that insert semi-automatically. Automatic insertion machines (AIM) are similar to these machines. However, they use simple tip applicators attached to single arms instead of robotic arms.

Solder Bumping Machine

This machine is similar to AIM, an automatic insertion machine. They use robotic arms that use heated pads for applying the conductive ink or the solder paste. A large opening at the bumped spot allows the components to fit in the pad. 

Leadless PCB construction

Placing individual components on a machine and applying solder paste helps make the PCB. In this assembly style, there is no solder mask on your PCBs. Therefore, it is very efficient to place many components in one hole with this style of board.

In-house Assembly

The most manufacturer has in-house assembly and can produce their PCB assemblies. It is one of the best methods for cutting costs as the manufacturer doesn't need to pay extra fees for the services.  

Conclusions

Thus, the cost of PCB assembly is determined by various factors. Thus, next time you want to cut down the cost, make sure you are familiar with all the aspects responsible for raising the PCB assembly cost. In the same way, you should also count for the types of products and design complexity. 

NextPCB is a reputed PCB manufacturer in China. We offer you our best quality service on PCB assembly for various circuits per your requirement. Moreover, we guarantee you quality service at an affordable price. 

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