What is Electronics Manufacturing

It is very easy to understand that electronics manufacturing means the production of any kind of electronic products, which are widely used in many industry areas, such as consumer electronics, industrial electronics, agricultural equipment, automotive, communication and wireless, lighting industry, IoTs, computer and storage, test and measurement, robotic, medical, military, aerospace and satellites etc. 

The electronics manufacturing process is the steps needed to assemble electronic components and parts through electronic and mechanical assembly and connection to make electronic products that meet the requirements of the design mission statement. Therefore, without a more advanced and mature operational electronic assembly process and technology, it is impossible to ensure the high quality and reliability of electronic products. 

10 Main Steps in Electronics Manufacturing

Generally speaking, the electronics manufacturing process includes the following aspects, such as PCB manufacturing, PCB assembly, box build assembly, functional testing, quality inspection and packaging. Here are the main processes for Electronics Manufacturing. 

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    Step 1: DFM Check

    Designing electronic devices is not just about making a functional product, but it is also about producing a design that is reliable, manufacturable and low cost. This technique of design evaluation is referred to as Design for Manufacturability or DFM. It is the first step of the electronics manufacturing process. Gross rejection due to design faults is very likely to happen if DFM is not done properly.

    DFM check involves reviewing the design and suitable materials in reference to applicable design rules and in consultation with the manufacturing team for robustness assessment. DFM addresses key areas like PCB pad design, trace width, and component locations. DFM also aims for a cost-effective design which can be done through the utilization of standard parts and simplifying the design as much as possible. Other considerations include proper thermal management, mechanical or dimensional constraints and test provisions. This is a proactive approach rather than correcting issues at the latter stages during production wherein there is already a massive amount of rejects due to design gaps. Assessing the design errors and correcting them will help shorten the product lead time.

    Viasion relies on DFM as a method to objectively analyze and optimize the design. Profitability, quality, and manufacturability are the company’s main motivations during electronic manufacture and design. With its years of experience, Viasion has established guidelines and best practices to have a cost-effective and robust electronics manufacture through the DFM tools.  

    Step 2: Sourcing PCBs and Electronic Components

    The Bill of Materials (BOM) is the main reference of Sourcing Teams in looking for potential vendors. The BOM indicates the materials that are meticulously selected based on electrical, mechanical, and thermal properties that are compatible with the assembly processes. Evaluating suppliers and weighing every performance metric is anchored on every company’s business strategy. Trade-offs are expected to arise when prioritizing a supplier characteristic. A weighted criteria analysis method is the most practical approach in supplier evaluation.

    Cost remains a main factor in sourcing a supplier for electronic parts and electronic manufacture. The supplier who can propose the lowest quoted price will gain the most advantage. A careful review of the quotation must be done to consider all the critical terms and conditions such as lead time, price, and minimum order quantity (MOQ).

    A strategic solution to minimize supply chain risk is to find alternative vendors or components. This is to ensure continuity in raw material supply in the event of unexpected shortages and issues. Note however that qualifying additional parts or suppliers will entail some costs related to qualification and maintaining multiple suppliers, to avoid issues in manufacturing electronics caused by supplier restraints.

    Step 3: PCB Assembly

    The PCB assembly is the critical step in electronics manufacturing process. In PCB assembly process, all the electronic components will be soldered on the PCB board. Usually, there are two kinds of component soldering methods: reflow sodering for SMT (Surface Mount Technology) components and wave soldering for PTH (Plated Through Hole) components. Besides, manually hand soldering is also needed on some occasions.

    In the PCB design stage, PCB designers should first determine the layout of SMD (placement) and DIP (insertion) on both the front and back sides of the PCB. Different assembly methods correspond to other processes and have additional requirements for production lines, which must be carefully considered.

    When PCB design files are finished, the PCB assembly house will check the BOM(Bill of List) and Pick-and-place files thoroughly, and then design proper production instructions including electronic board manufacturing process, methods, parameters and fundamental issues to be considered for any specified type of PCB.

    Standardize the PCB assembly process by specifying the relevant parameters in production, ensuring that the PCBA meets the technical specification requirements of manufacturability, testability, safety, EMC, EMI, etc., And then, the advantages of electronics manufacturing in terms of process, technology, quality as well as cost are created.

    Reflow Soldering

    Reflow soldering means the technique and process of soldering components and PCBs using a reflow oven. The connection of surface mount components to PCB pads is achieved by melting the solder paste pre-assigned to the PCB pad. It is the most widely used electronic circuit board manufacturing process because of its high efficiency and low cost.

    The purpose of the reflow procedure is to gradually melt the solder and slowly heat the connection interface to avoid rapid heating that could cause damage to the electronic components. A traditional reflow soldering process usually has four stages called “Zones”. Each zone has its temperature profile: “preheat”, “immersion”, “reflow”, and “cooling”. 

    Surface-mount technology uses a specific tool to align the pins of SMD components with the pre-coated adhesives and solder paste on the pads, mount the SMD components on the PCB surface, and then perform reflow soldering, establishing a reliable mechanical and electrical connection between SMD components and the circuit. 

    PCB Assembly Processes for Different Kinds of PCBs

    A unique electronic manufacturing process should be used for every single type of PCB, according to its component type, density, and layout. Mainly we need to think: Do components exist on one side or two sides? Are surface mount components, through-hole components or mixed?

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

    Incoming material inspection → silkscreen solder paste  → placing components → drying (curing) → reflow soldering → cleaning → testing → rework

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

    Incoming material inspection → applying solder past on B side of PCB → placing components → drying (curing) → reflow soldering → cleaning → applly solder paste on A side of PCB → placing components → drying (curing) → reflow soldering → cleaning → testing → repair

    Type III. Single-sided mixed mounting 

    Surface mount components and leaded(PTH)  components are mixed, but components just exist on one side of the PCB. 

    Incoming inspection → silkscreen solder paste for PCB (SMT red glue) → placing components → drying (curing) → reflow soldering → cleaning → DIP → wave soldering → cleaning → inspection → rework

    Type IV. Double-sided mixed assembly

    SMT components and THT components are mixed, components are exist on both sides of the PCB.

    Double sided PCB assembly with mixed PTH and SMT

    Wave soldering

    In the wave soldering process, the PCB with the pre-installed electronic components will run through the melted tin wave, then the melted tin will adhere to the pins of the THT (Though-hole technology) components and the PTH(plated through hole) wall. After cooling, the tin will consolidate the components pins with the PTH wall, and form a permanent connection between PCB and electronic components.

    There are two critical factors in wave soldering: the speeding of the PCBs running through the tin and the height of the tin wave. Very experienced engineers are needed to adjust these parameters according to the characteristics of every single type of PCB, such as the component quantity, size, weight, type., etc.

    Although SMT components are more and more widely used because of their high production efficiency. But THT components are still used widely, especially for the ones that need reliable connections. So wave soldering is also one of the two most important electronic board manufacturing processes. Comparing hand soldering, the wave soldering process can reduce the volume of electronic products further and still use through-hole components at a low price.

    However, wave soldering also has some limitations. For example, the wave soldering process requires more equipment and more human labour. In addition, it is prone to more defects comparing SMT assembly. Finally, it is challenging to achieve high-density assembly. 



    Distance between plug-in components and other components


    The selected solder mainly determines the soldering temperature. The following diagram shows the reflow and wave soldering windows.

    Step 4: IC Programming

    Electronic manufacture may also pass through the IC programming process, wherein a customized program or the latest revision of the program can be coded into the product. IC refers to “Integrated Circuits” which are the chips that are packaged to be able to be electrically connected to the other parts of the electronic product. A single IC may consist of diodes, resistors, and transistors. A typical programming cycle includes coding, reading, and verification of the program to ensure that it is loaded accordingly.

    IC programming can be done during the prototyping and mass production stages of the electronic manufacture. A preferred supplier should have the technical competence in developing tools for IC programming to rapidly prototype, revise codes as necessary, and finalize the design in the most efficient way. The device should be able to accommodate software revisions during production to easily perform IC programming updates. IC programmers utilize interface boards and cables to be able to write codes into the circuit.

    Step 5: Functional Testing

    In functional testing, power is applied while simultaneously simulating the operating environments of the product to understand its output and behaviour. It involves a dedicated test fixture that is specifically designed to determine the characteristic performance of the product. The product’s response is compared against the design specifications to know if it is operating properly. Function testing is an important step in the electronic manufacturing process to ensure the quality of electronic products. The test yield percentage is calculated based on the number of passing parts and the total tested parts. Function testing is quite imporant step in electronic manufacturing process to ensure the quality of electronic products.

    Viasion’s team of test experts will assist you with your functional testing needs. Viasion collaborates with clients in reviewing test specifications and qualifying and validating the test program. We understand the importance of functional testing as a prerequisite in delivering parts that meet the standards.

    Step 6: Box Build Assembly

    Box Build Assembly is a type of electronic manufacture service wherein the different sub-parts are integrated into an electronic enclosure to end with a functional unit. The sub-parts to be assembled include the printed circuit boards, wire harnesses and other electromechanical parts. The housing or enclosure should possess the structural and mechanical properties to protect the internal system from outside stresses such as temperature, humidity, and vibration. 

    This type of assembly can be customized and can range from simple to more complex sub-assemblies. First, the complete set of materials and parts that are required to assemble the product is selected and procured. The parts can be off-the-shelf or customized according to your design requirements. Box build assembly service providers can also be the same supplier to fabricate and assemble the printed circuit boards (PCBA). Next is the assembly of the components together inside the enclosure which can be done either manually or through automation. The final product is being tested to verify if it is compliant with the performance requirements. Other sub-processes also include soldering, wiring, and harnessing. 

    Viasion is a trusted box-build assembly supplier with a technically capable facility and competent team support. At Viasion, we highly value quality in electronics manufacture process until the products are completely shipped to our customers. Flexibility is our strength from assembling simple designs to complex box-build assemblies.

    Step 7: Burn In Test


    Burn-in Testing is another quality screening process through application of voltage and temperature to accelerate latent defects of the products. Depending on customer requirements, voltage values, temperature and burn-in duration are being controlled to detect failing products. A burn-in oven contains slots or mesh tray, in which burn-in boards are loaded. 

    Burn-in Boards consist of sockets to which the units are mounted or inserted. The boards and the sockets have specific tool life, usually measured in terms of number of insertions or loading and must be monitored and maintained to ensure proper testing of the units. The board and socket material should also be able to withstand high temperature and repetitive bias cycling. Units that fail burn-in testing are screened out and gross rejections are being investigated for further failure analysis.

    The ovens should also be regularly calibrated and should undergo preventive maintenance to have consistent and accurate temperature and testing capabilities. During preventive maintenance, the active and passive parts of the burn-in boards are checked and replaced when necessary. The productivity of the burn-in test process is dictated by the oven capacity, burn-in duration and the board capacity.

    PCB burn in tests

    Step 8: Custom Packaging

    In designing custom packaging, the physical attributes, functionality, and sensitivity of the electronic product must be scrutinized. The main purpose of custom packaging includes protection against mechanical stresses during transport and handling, shielding from environmental factors such as heat, pressure, and moisture and ESD protection caused by the charging and discharging of materials. An improper package may ruin the successful electronic manufacture. The packaging should also contain other product information such as Batch or Lot number and quantity and should also present the company logo.

     The dry packing method can be done using a moisture barrier bag, desiccants and a humidity card for electronic products that are moisture sensitive. Different packing configurations can be discussed with the customer and should be aligned with the current industry trends and requirements. In custom packaging, environmental and government regulations should be considered to avoid non-compliance.

    Viasion offers custom packaging that is well-assessed and qualified through engineering evaluations. The packaging undergoes a series of verifications and tests to know that the packaging will be able to secure the parts during transportation.

    Step 9: Outgoing Quality Control (OQC)

    The packaged units are subjected to Outgoing Quality Control (OQC) otherwise known as Outgoing Quality Buy-off to ensure that the product has the correct traceability, actual contents, physical appearance, and quantity of the finished goods. Skipping OQC will make the manufacturer suffer huge consequences such as mixed products, quantity discrepancy and defect escapees. So OQC is a critical electronic manufacturing process.

    The manufacturer should have a set of inspection guidelines with clear methodology, frequency, and criteria to be able to detect non-conforming products. In case of rejection, certain additional inspections and tests may be required to confirm rejection and screening of the affected lot. The content of the packaging must also be verified against the label content for accuracy checking.

    A wrong decision during the inspection may result in the acceptance of rejected parts or even the rejection of acceptable parts. Incorrect screening will result in serious customer complaints. OQA eliminates potential product returns and warranty compensations that are costly and time-consuming. Viasion puts a priority on product quality and has comprehensive OQA guidelines to help effectively ship parts that are manufactured according to specifications.

    Step 10: Distribution

    Distribution is the last step of electronics manufacturing process. It is the process of transporting the product from the electronics factory to the customer's store or warehouse. It must be done in such a way that the products are protected against external forces to prevent damaged goods from reaching the customer. The risk of deformation and damage brought about by too much heat and humidity must be minimized. A successful distribution process means that the product has reached its intended destination at the right time and is in good condition.

    Latest technologies are being utilized to enhance distribution processes such as automated tracking of shipment status. This auto-tracking allows customers to virtually know the physical location of the orders. Any issues are immediately informed to customers and suppliers so that delays are addressed efficiently. A seamless distribution process is also made possible through automated invoicing, system-based transactions, and smart applications, which is a great help to electronics manufacture.

    Tips in Electronic Manufacture

    PCB design, components selection and assembly techniques

    1. Principle of component selection

    On the premise of meeting performance indexes and structural installation, preferentially select components that can reduce production costs.

    Beside, The selection of the component package on the PCB should ensure that the package is consistent with the physical outline of the component, pin spacing, through-hole diameter, etc. For example, inserted component pins should fit well with the through-hole tolerance, usually, the through-hole diameter should be 8-20mil larger than the pin diameter to ensure good solder penetration.

    2. Advice to components choice and design

    1. Small (short) components cannot be placed in the middle of significant (tall) components; (judged based on 2.0mm). 
    2. The gap between PLCC, QFN, QFP, and SOP themselves and each other should be ≥ 2.5 mm. 
    3. The gap between QFP, SOP and Chip, SOT should be ≥ 1 mm. 
    4. The distance between PLCC, QFN and Chip, SOT should be≥ 2mm.
    5. The clearance between the BGA profile and other components should be ≥ 3 mm, 5 mm is  recommended. 
    6. The clearance between the PLCC surface mount pedestal and other components should be ≥ 3 mm. 
    7. Surface mount connectors and connectors should leave a gap between them to ensure they can be inspected and reworked. In general, the lead side of the connector should have a space larger than the height of the connector.
    8. Check with your contract electronic manufacture factory if you have any doubts.

    3. Selection of the soldering process

    Since every PCB has its own design with different shapes, components and materials. So we should choose the suitable electronic circuit board manufacturing process for every single type of PCB. Most importantly, we need to consider if the components exist on one side or two sides, and if there are only SMT components, only PTH components or SMT and PTH mixed.

    Assembly method Schematic diagram Soldering methodFeatures
    Single-sided PCBAReflow soldering on the single sideSimple process, suitable for small, thin and simple circuits
    Double-sided PCBAReflow soldering on both sidesHigh-density assembly, thin profile
    SMD and DIP both on side AFirst reflow soldering on side A, then  wave soldering on side BGenerally adopt the way of placing components first and then inserting.The process is simple.
    DIP on side ASMD on side Bwave soldering on side BLow PCB cost and simple processAdopt SMD first and then DIP.
    DIP on side ASMD on side A and BFirst reflow soldering on side A and B, then  wave soldering on side BSuitable for high-density assembly
    SMD and THC on both side A and BFirst reflow soldering on side A and B, then  wave soldering on side BFirst adopt DIP on side B and then manual solderingThe process is complex and rarely used.


    4. PCB material selection

    Different substrate materials can be divided into rigid and flexible PCBs according to whether they can be flexed; high Tg substrates and regular Tg substrates according to Tg value; FR4, CEM, ceramic, metal core, non-PTFE high-frequency materials, PTFE high-frequency materials, etc according to their electrical properties. PCB designers should choose the most suitable material according to the functions, usage, price level., etc. It is a good idea to ask PCB manufacturers for advice. 

    5. Advice to PCB design and layout

    Components Layout: Components are arranged as regularly and evenly as possible. The positive pole of polarized components, the gap of integrated circuits, etc., are placed uniformly, facing up and to the left. If wiring difficulties, there can be exceptions. Regularly arranging the components is convenient for inspection and improving the placement/insertion speed. The uniform distribution of components facilitates the optimization of heat dissipation and the soldering process. Considering the need for soldering, inspection, testing, and installation, the components should not be spaced too close to each other. Component layout is very important for successful electronic assembly manufacturing.

    PCB Thickness: PCB thickness refers to its nominal thickness (i.e., the thickness of the insulation layer plus copper foil), and the PCB thickness should be selected based on the structure, size of the board, and weight of the installed components.

    PCB Surface Treatment: The most basic purpose of surface finish is to ensure good solderability or electrical properties. However, since copper in nature tends to exist as an oxide form in the air, it is unlikely to remain as the original copper for long periods of time.

    Although in subsequent assemblies Although intense fluxes can be used to remove most copper oxides in the following assemblies, intense fluxes themselves are not easily removed, so the industry generally does not use strong fluxes.

    So other treatments of copper are required, such as HAL, OSP, ENIG, immersion tin, silver., etc. PCB design engineers should choose the proper surface treatment according to the component density, usage and cost mostly.

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    Viasion Technology is your trusted partner & one-stop shop for PCB fabrication, components sourcing, PCB assembly and electronic manufacturing. With more than 16 years of experience, we have been supplying high-quality PCBs with competitive pricing for 1000+ customers worldwide. Our company is ISO9001:2015 Certified & UL Listed, and all our products are 100% E-tested and inspected by AOI & X-RAY to meet the highest industry standards. So please get an instant quote from our sales team now, and we will take care of the rest.