Electronic Manufacturing Process

What is Electronics Manufacturing

Electronics manufacturing involves the production and assembly of a wide range of electronic products used across various industries. From consumer electronics, industrial devices, and agricultural equipment to automotive systems, wireless communication, lighting, IoT devices, computers, medical equipment, and even aerospace technology, electronics manufacturing plays a crucial role in many sectors.

The electronics manufacturing process consists of a series of essential steps designed to assemble and connect electronic components and parts, both mechanically and electronically. This process ensures the final electronic products meet the specifications outlined in the design mission statement. Advanced and mature assembly technologies are vital to maintaining high standards of quality, performance, and reliability in these products.

10 Main Steps in Electronics Manufacturing

Finally, the manufacturing process concludes with packaging, where products are securely packed to ensure safe shipping and delivery. By carefully executing each of these stages, electronics manufacturers are able to produce reliable, high-performance products for a wide range of industries.

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Step 1: DFM Check

In electronic manufacturing, creating a functional device is only part of the process. A successful design must also be reliable, easy to manufacture, and cost-effective. This crucial aspect of design optimization is known as Design for Manufacturability (DFM). DFM is the foundational step in the electronic manufacturing process, ensuring that design flaws are addressed early, minimizing the risk of costly rejections during production.

A thorough DFM check involves reviewing the design in detail, assessing material suitability, and aligning it with industry design standards. This process is done in close collaboration with the manufacturing team to ensure robustness and efficiency. Key areas of focus in DFM include PCB pad design, trace width, and the strategic placement of components. Cost-effective designs are prioritized by using standard components and simplifying the overall structure. Additionally, factors such as thermal management, mechanical constraints, and testing provisions are carefully considered to prevent future complications.

DFM takes a proactive approach, aiming to resolve potential design issues early in the process, rather than addressing them during production when significant time and resources have already been invested. By identifying and correcting design errors upfront, manufacturers can significantly reduce lead times and improve product quality.

At ESPCBA, DFM is a cornerstone of the company’s strategy for optimizing electronic design and manufacturing. With years of industry expertise, ESPCBBA has developed proven DFM guidelines and best practices, ensuring cost-effective, high-quality, and manufacturable designs. This focus on DFM enables ESPCBA to deliver reliable and profitable electronic products to market efficiently.

By integrating Design for Manufacturability into every stage of product development, ESPCBA ensures that electronic designs not only perform as intended but are also optimized for large-scale production.

Step 2: Sourcing PCBs and Electronic Components

In the electronic manufacturing process, the Bill of Materials (BOM) serves as the primary reference for sourcing teams when selecting potential vendors. The BOM lists the materials carefully chosen for their electrical, mechanical, and thermal properties, ensuring compatibility with the assembly processes. Supplier evaluation is closely aligned with a company’s business strategy, requiring a balance between various performance metrics. Using a weighted criteria analysis is the most effective method for evaluating suppliers and making trade-off decisions.

While various factors are considered, cost remains a critical element when sourcing suppliers for electronic parts and manufacturing services. The supplier offering the most competitive price will typically have an advantage. However, it’s essential to thoroughly review each quotation, taking into account key terms like lead time, price, and minimum order quantity (MOQ) to ensure a complete understanding of the deal.

To mitigate supply chain risks, manufacturers often adopt a strategic approach by sourcing alternative vendors or components. This helps maintain a consistent supply of raw materials in case of unexpected shortages or disruptions. However, qualifying additional suppliers may involve added costs due to the need for testing and ongoing management of multiple sources, which helps prevent potential manufacturing delays or issues due to supplier constraints.

By maintaining a well-structured BOM and developing a resilient sourcing strategy, manufacturers can optimize electronic production and reduce risks related to supplier reliability and material availability. This approach ensures a steady flow of materials while controlling costs, leading to efficient and successful electronic manufacturing processes.

Step 3: PCB Assembly

The PCB assembly process is a crucial phase in electronics manufacturing, where all electronic components are soldered onto the printed circuit board (PCB). There are typically two primary methods used for component soldering: reflow soldering for Surface Mount Technology (SMT) components, and wave soldering for Plated Through Hole (PTH) components. In certain cases, manual hand soldering is also necessary to complete the assembly process.

During the PCB design stage, designers need to carefully plan the placement of both SMD (Surface Mount Devices) and DIP (Dual In-line Package) components on both sides of the PCB. Each assembly method has specific production requirements and processes, which must be considered to ensure efficient and accurate manufacturing.

Once the PCB design files are finalized, the PCB assembly house will thoroughly review the Bill of Materials (BOM) and pick-and-place files. From there, they will develop detailed production instructions that outline the PCB manufacturing process, including the methods, parameters, and any special considerations required for the specific PCB type.

By adopting optimized assembly practices, manufacturers can produce high-quality, reliable electronic products while reducing errors and minimizing production delays. Efficient PCB assembly is crucial for ensuring smooth, cost-effective electronics manufacturing.

To ensure a seamless PCB assembly process, it is essential to standardize production by defining key parameters. This guarantees that the assembled PCB (PCBA) meets all critical technical specifications, including manufacturability, testability, safety, as well as EMC (Electromagnetic Compatibility) and EMI (Electromagnetic Interference) requirements..

Reflow Soldering

A side

In the IPC standard, the packaging and interconnecting structure on the master drawing is referred to as the Primary Side, where most of the complex components are mounted. For convenience, this is called the A-side, corresponding to the TOP side in EDA software. In different types of boards, the A-side varies: for backplanes, it’s where the veneer is inserted; for DIP boards, it’s the component side; and for SMT boards, it’s the side with more ICs or larger components.

B side

In electronic manufacturing processes, the IPC standard refers to the side of the interconnect structure opposite the Primary Side as the Secondary Side. For ease of reference, this is often called the “B-side,” corresponding to the BOTTOM layer in EDA (Electronic Design Automation) software. Typically, the B-side houses fewer components and involves less complex parts compared to the primary side. In the case of DIP (Dual In-line Package) boards, the B-side is also known as the solder side.

Reflow soldering is a widely-used technique in PCB assembly, where components are soldered to the board using a reflow oven. The process works by melting solder paste applied to the PCB pads, creating secure connections for surface-mount components. Reflow soldering is favored in electronic circuit board manufacturing due to its high efficiency and cost-effectiveness.

The goal of the reflow process is to carefully melt the solder while gradually heating the connection points to avoid damaging sensitive electronic components. The process typically follows four stages, known as zones, each with a specific temperature profile: preheat, immersion, reflow, and cooling.

In Surface Mount Technology (SMT), precise tools are used to align the pins of SMD components with the pre-applied adhesives and solder paste on the PCB pads. After mounting the components, reflow soldering creates strong mechanical and electrical connections, ensuring reliable functionality of the electronic circuits. Reflow soldering plays a critical role in achieving high-quality and cost-efficient electronics manufacturing.

PCB Assembly Processes for Different Kinds of PCBs

Each type of PCB requires a tailored electronic manufacturing process based on its component type, density, and layout. Key considerations include whether components are mounted on one or both sides of the board, and whether the design uses surface-mount components, through-hole components, or a combination of both. Customizing the manufacturing process ensures optimal performance and efficiency for each specific PCB design.

Type I: Single-sided assembly (only SMT components):

The electronic manufacturing process involves the following steps: Incoming material inspection → Solder paste application (silkscreen) → Component placement → Drying (curing) → Reflow soldering → Cleaning → Testing → Rework. These steps ensure a high-quality and efficient PCB assembly process.

Type II. Double-sided assembly(only SMT components):

The streamlined electronic manufacturing process includes: Incoming material inspection → Solder paste on B-side → Component placement → Drying → Reflow soldering → Cleaning → Solder paste on A-side → Component placement → Drying → Reflow soldering → Cleaning → Testing → Repair. This ensures an efficient, high-quality PCB assembly.

Type III. Single-sided mixed mounting

For PCBs with a mix of surface mount components and leaded (PTH) components on one side, the electronic manufacturing process follows these steps:

Incoming inspection → Solder paste application (SMT red glue) → Component placement → Drying (curing) → Reflow soldering → Cleaning → DIP insertion → Wave soldering → Cleaning → Inspection → Rework. This optimized process ensures efficient assembly and high-quality results.

Type IV. Double-sided mixed assembly

For PCBs with a mix of SMT components and THT components on both sides, a specialized electronic manufacturing process is required to ensure efficient assembly and high quality.

The process for PCBs with both SMT and DIP components involves the following steps: Incoming inspection → Applying SMD adhesive on the B-side of PCB → Component placement → Curing → Flipping the PCB → DIP insertion on the A-side → Wave soldering → Cleaning → Testing → Repair. This method prioritizes SMT before DIP, making it ideal for PCBs with a higher concentration of SMD components.

Incoming inspection → DIP on A-side of PCB (pin bending) → Flip the board → Apply SMT red glue on B-side → Component placement → Curing → Flip the board → Wave soldering → Cleaning → Testing → Repair. This approach prioritizes DIP before SMT, making it ideal for PCBs with a higher number of through-hole components compared to SMD components.

The manufacturing process for mixed assemblies on the A-side and SMT on the B-side follows these steps: Incoming inspection → Apply silkscreen solder paste on A-side of PCB → Component placement → Curing → Reflow soldering → DIP insertion and pin bending → Flip board → Apply SMT red glue on B-side → Component placement → Curing → Flip board → Wave soldering → Cleaning → Inspection → Repair. This process ensures efficient assembly for PCBs with mixed components on the A-side and SMT components on the B-side.

The electronic manufacturing process for mixed assemblies on the A-side and SMT on the B-side includes the following steps: Incoming inspection → Apply SMT red glue on the B-side → Place components → Curing → Flip the board → Apply silkscreen solder paste on the A-side → Place components → Reflow soldering on the A-side → DIP insertion → Wave soldering on the B-side → Cleaning → Inspection → Repair. In this process, SMD components are placed on both sides, followed by reflow soldering, then DIP components, and finally, wave soldering.

The electronic manufacturing process for PCBs with mixed assemblies follows these steps: Incoming inspection → Apply silkscreen solder paste (SMT red glue) on B-side → Component placement → Drying (curing) → Reflow soldering → Flip the board → Apply silkscreen solder paste on A-side → Component placement → Drying → Reflow soldering (partial soldering possible) → DIP insertion → Wave soldering. This process ensures efficient assembly with SMT on both sides and reliable soldering for mixed components.

Wave Soldering

Wave soldering is a key process in electronic manufacturing, especially for assembling printed circuit boards (PCBs) that use through-hole technology (THT) components. In this process, the PCB with pre-installed components moves through a wave of molten solder. As it passes through the solder wave, the molten tin adheres to the pins of the THT components and the walls of the plated through holes (PTH). Once the solder cools, it solidifies, forming a strong and permanent bond between the components and the PCB.

Two crucial factors determine the success of the wave soldering process: the speed at which the PCB moves through the molten solder and the height of the solder wave. Both of these parameters must be carefully adjusted according to the specific characteristics of each PCB. Variables such as the number of components, their size, weight, and type all play a role in determining the appropriate settings. Experienced engineers are needed to fine-tune these adjustments, ensuring that the solder forms a high-quality, reliable connection with minimal defects.

Distance between plug-in components and other components

On the front side of the PCB, ensure a minimum 1.5mm distance between the DIP component body and surrounding components.

The back of DIP components is the surface to be soldered in electronic manufacturing.

The solder type primarily determines the soldering temperature, as shown in the reflow and wave soldering windows diagram.

Step 4:IC Programming

In electronic manufacturing, the IC programming process is often utilized to code a customized program or the latest software revision into the product. IC, or “Integrated Circuits,” refers to the chips that electrically connect to other components in the device. Each IC may contain diodes, resistors, and transistors. The typical IC programming cycle involves coding, reading, and verification to ensure accurate program loading, optimizing functionality and performance in the final product.

IC programming is essential in both the prototyping and mass production stages of electronic manufacturing. A reliable supplier must possess the technical expertise to develop IC programming tools that enable rapid prototyping, code revisions, and efficient finalization of the design. During production, the device should support software revisions to facilitate seamless IC programming updates. IC programmers use specialized interface boards and cables to write code directly into the circuit, ensuring smooth integration and functionality throughout the manufacturing process.

Step 5:Functional Testing

In the electronic manufacturing process, functional testing is a critical step to ensure product quality and reliability. During functional testing, power is applied to the product while simulating its operating environments to analyze its behavior and output. A dedicated test fixture is used to evaluate the product’s performance characteristics. The product’s responses are then compared against the original design specifications to verify proper operation.

The test yield percentage is calculated by comparing the number of passing units to the total number of tested units, providing insight into overall quality and manufacturing efficiency. Functional testing is essential in guaranteeing that electronic products meet required standards before they reach the market.

Viasion’s team of testing experts is ready to support your functional testing needs. We work closely with clients to review test specifications, and qualify and validate test programs, ensuring your products meet the highest standards of performance and reliability.

Step 6:Box Build Assembly

Box Build Assembly is a comprehensive electronic manufacturing service where various sub-components are integrated into an electronic enclosure to create a fully functional unit. These sub-components typically include printed circuit boards (PCBs), wire harnesses, and other electromechanical parts. The enclosure must offer the necessary structural and mechanical properties to protect the internal system from environmental factors like temperature fluctuations, humidity, and vibration.

This assembly process is highly customizable and can range from simple to complex sub-assemblies. The process begins with the selection and procurement of all materials and parts needed to assemble the final product. These components can either be off-the-shelf or customized according to specific design requirements. Often, the same supplier who handles the printed circuit board assembly (PCBA) can also provide box build services. Once all parts are ready, the components are assembled into the enclosure, either manually or using automation. After assembly, the final product undergoes rigorous testing to ensure it meets all performance and quality standards. Additional processes, such as soldering, wiring, and harnessing, are often involved.

Viasion is a trusted provider of box-build assembly services, with a technically advanced facility and a skilled team. We prioritize quality at every stage of the electronic manufacturing process, ensuring that each product is thoroughly tested before shipment. Whether your design is simple or complex, Viasion offers flexible solutions to meet your box-build assembly needs.

Step 7:Burn In Test

Burn-in Testing is a critical quality control process in the electronic manufacturing industry that involves applying voltage and temperature to products to accelerate the detection of latent defects. This process helps identify potential failures before products reach the market. The voltage, temperature, and duration of the burn-in test are carefully controlled based on customer specifications to ensure that any failing units are detected early. Products are tested in a burn-in oven, which contains slots or mesh trays where burn-in boards are loaded.

Burn-in boards are equipped with sockets where the units are mounted or inserted for testing. These boards and sockets have a specific tool life, typically measured by the number of insertions or load cycles. Regular monitoring and maintenance of these components are crucial to ensure the accuracy and effectiveness of the burn-in test. The materials used in the boards and sockets must withstand high temperatures and repetitive bias cycling to maintain performance during testing. Units that fail the burn-in test are screened out, and any gross rejections are further analyzed for the root cause of failure.

Step 8:Custom Packaging

When designing custom packaging for electronics manufacturing, it is essential to consider the product’s physical characteristics, functionality, and sensitivity. The primary goal of custom packaging is to protect electronic components from mechanical stresses during shipping and handling, as well as environmental factors like heat, pressure, moisture, and electrostatic discharge (ESD). Without proper packaging, electronic products risk damage, leading to potential failure during production. Additionally, packaging should include vital product information, such as batch or lot numbers, quantities, and company branding.

For moisture-sensitive electronics, the dry packing method is commonly used. This involves utilizing moisture barrier bags, desiccants, and humidity indicator cards to safeguard the product. Custom packaging solutions can be tailored based on customer needs, ensuring alignment with industry trends and regulatory standards. Compliance with environmental and governmental regulations is also crucial to avoid penalties and ensure sustainable packaging practices.

At ESPCBA, we specialize in providing high-quality custom packaging solutions, rigorously tested and engineered for maximum protection.

Step 9:Outgoing Quality Control (OQC)

In electronics manufacturing, Outgoing Quality Control (OQC), also known as Outgoing Quality Buy-off, is a critical process to ensure the accuracy and quality of packaged units before shipment. OQC verifies the traceability, actual contents, physical appearance, and quantity of finished goods. Skipping this essential step can lead to costly issues such as product mix-ups, quantity discrepancies, and undetected defects, significantly impacting both the manufacturer and the customer.

Manufacturers must establish clear inspection guidelines that outline the methodology, frequency, and criteria for detecting non-conforming products. In the event of a rejection, additional inspections and tests may be necessary to confirm the issue and screen the affected batch. It is equally important to verify that the packaging contents match the label for accuracy.

A wrong decision during the OQC process can result in accepting defective products or rejecting good ones, leading to serious customer complaints and product returns. Effective OQC helps eliminate these risks, reducing the likelihood of costly returns and warranty claims. At Viasion, we prioritize product quality with a comprehensive Outgoing Quality Assurance (OQA) process, ensuring that all parts meet specifications before they are shipped to our customers.

Step 10: Distribution

In the electronics manufacturing process, distribution represents the final and crucial phase, involving the transport of finished products from the production facility to the customer’s designated location, such as a retail store or warehouse. Ensuring safe transit is essential, as electronic components are particularly sensitive to external stressors, such as impact, vibration, or environmental factors. Proper packaging and logistics strategies are critical to mitigate the risks of product deformation or damage due to excessive heat or humidity, preserving product integrity upon delivery.

With advancements in technology, distribution processes are increasingly optimized through automated systems. Real-time shipment tracking allows customers and suppliers to monitor the precise location of goods throughout the delivery chain. This visibility helps to quickly identify and resolve any issues that might cause delays. Furthermore, the use of automated invoicing, system-based logistics transactions, and integrated smart applications significantly enhances operational efficiency, streamlining the overall distribution workflow for electronics manufacturers. By leveraging these innovations, manufacturers can ensure on-time delivery and maintain product quality throughout the supply chain, supporting customer satisfaction and reducing costly disruptions.

Tips in Electronic Manufacture

PCB design, component selection, and assembly are key to electronics manufacturing.

1.Principle of component selection

When designing for electronics manufacturing, it’s crucial to choose components that meet performance requirements while minimizing production costs. Additionally, the selection of component packages on the PCB must align with the physical dimensions, including pin spacing and through-hole diameters. For instance, through-hole components should fit precisely, with the hole diameter being 8-20 mils larger than the pin to ensure proper solder penetration and secure assembly.

2.Advice to components choice and design

Short components (<2.0mm) should not be placed between taller components during electronics manufacturing.

The gap between PLCC, QFN, QFP, and SOP components should be at least 2.5mm in electronics manufacturing.

The gap between QFP, SOP, and chip or SOT components should be at least 1mm in the electronics manufacturing process.

In electronics manufacturing, the distance between PLCC, QFN, and chip or SOT components should be at least 2mm.

In the electronics manufacturing process, ensure a clearance of at least 3mm, with 5mm recommended, between the BGA profile and other components.

In electronics manufacturing, maintain a clearance of at least 3mm between the PLCC surface mount pedestal and other components.

In electronics manufacturing, ensure a gap between surface mount connectors to facilitate inspection and rework.

If you have any questions, consult with your contract electronics manufacturing factory for clarification.

3. Selection of the soldering process

Each PCB has a unique design with varying shapes, components, and materials. Therefore, it’s essential to select the appropriate electronic circuit board manufacturing process for each PCB type. Key considerations include whether the components are on one side or both sides of the board and if the PCB uses only SMT components, only PTH components, or a combination of SMT and PTH.

Assembly method	Soldering method	Features
Single-sided PCBA	Reflow soldering on the single side	Simple process, suitable for small, thin and simple circuits
Double-sided PCBA	Reflow soldering on both sides	High-density assembly, thin profile
SMT and DIP both on side A	First reflow soldering on side A, then wave soldering on side B	Generally adopt the way of placing components first and then inserting. The process is simple.
DIP on side ASMT on side B	wave soldering on side B	Low PCB cost and simple process Adopt SMT first and then DIP.
DIP on side ASMT on side A and B	First reflow soldering on side A and B, then wave soldering on side B	Suitable for high-density assembly
SMT and THC on both side A and B	First reflow soldering on side A and B, then wave soldering on side B First adopt DIP on side B and then manual soldering	The process is complex and rarely used.

Notes:

In the electronics manufacturing process for mixed assembly, start with reflow soldering on the A side, followed by reflow soldering on the B side. Afterward, perform DIP (Dual In-line Package) component installation and complete the process with wave soldering using a fixture.

In the electronics manufacturing process, for single-sided reflow soldering and wave soldering, certain SMD devices like BGA, 0402, 0201, QFN, and PLCC should not be wave soldered.

For SMT boards with components on both sides, reflow soldering is applied twice. During the second reflow, the solder joints on the first side can remelt, potentially causing heavier components to shift. To prevent this, position heavier components on the A-side and lighter ones on the B-side to ensure stable soldering and reliable component placement.

In the electronics manufacturing process, the B side of a mixed-assembly board is soldered using wave soldering. To ensure effective soldering, the type, orientation, and spacing of components on this side must adhere to specific guidelines.

4. PCB material selection

In the electronics manufacturing process, PCB substrate materials are categorized based on flexibility into rigid and flexible PCBs. They are also classified by Tg value into high Tg and regular Tg substrates, and by electrical properties into FR4, CEM, ceramic, metal core, non-PTFE high-frequency materials, and PTFE high-frequency materials. PCB designers should select the most suitable material based on functionality, application, and cost considerations. Consulting with PCB manufacturers for expert advice is recommended to make the best choice.

5. Advice to PCB design and layout

For optimal electronics manufacturing, arrange components as regularly and evenly as possible. Polarized components should have their positive poles aligned consistently, and gaps between integrated circuits should be uniform, with components facing up and to the left whenever feasible. While exceptions may be necessary due to wiring constraints, a regular layout aids in inspection, speeds up placement and insertion, and enhances heat dissipation and soldering efficiency. Proper spacing between components is crucial to facilitate soldering, inspection, testing, and installation. Effective component layout is key to a successful electronic assembly process.

PCB thickness, defined as the combined thickness of the insulation layer and copper foil, should be chosen based on the board’s structure, size, and the weight of the installed components. Selecting the appropriate PCB thickness ensures structural integrity and optimal performance in the electronics manufacturing process.

6. PCB surface treatment selection:

The primary goal of PCB surface finish is to ensure optimal solderability and electrical performance. Copper naturally oxidizes over time when exposed to air, which can impair its effectiveness. While strong fluxes can remove copper oxides during assembly, they are difficult to clean and are generally avoided in the industry.

To address this, various copper treatments are employed, including HAL, OSP, ENIG, immersion tin, and silver. PCB design engineers should select the appropriate surface treatment based on component density, application requirements, and cost considerations.

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