High-Quality PCB Assembly Since 2007

  • Single-sided & Double-sided SMT assembly
  • Consigned PCB assembly, Partial Turnkey & Full turnkey assembly
  • No minimum order quantity and competitive pricing
  • E-test, AOI, X-ray, ICT, FCT, Burn-in Test
  • ISO9001:2015, ISO 13485:2016 Certified & UL Listed
  • Min. 0201 components, BGA, micro-BGA, QFN, DFN, CSP etc.

An introduction to SMT Assembly

Do you know exactly about SMT assembly? Why not learn more about SMT assembly by taking a glimpse at this article?
SMT is a shorthand for Surface Mount Technology. It is about the process of assembling the components on the surface of the printed circuit board directly. It is different from PTH assembly. PTH assembly is plated through hole assembly, which means we plug the component pins in the PCB hole first and then solder the pins in the holes.
Because today the electronic industry develops so fast, electronic products become smaller and more complex. To adapt to such a trend, engineers adopt the method of SMT assembly/SMT manufacturing. When some people take a look at the printed circuit boards with components of electronic products (smartphones, computers, medical electronics, telecommunication electronics or car electric parts, etc.), they may wonder how these components are mounted on the boards. Let’s reveal the answer they are mounted by the SMT assembly.
When you search pictures of SMT assembly factories, you can find out the prevailing presence of advanced automatic pick & place machines.

Why Should We Use SMT Assembly?

Generally speaking, electronic product manufacturers would more likely to use SMT technology to produce their products, because SMT manufacturing can make the production more time-efficient and cost-saving. Please refer to the following details.
  • The products need to be designed as small as possible

Because a lot of products on the market demand become smaller and smaller now, such as smartphones, cameras, wearable electronics, GPS trackers, blue tooth earphones, etc. That’s the reason why the electronic components used to make those products also become smaller and smaller.

  • The efficiency of SMT assembly is much higher

As we all know, the automatic pick and place machine can run very fast, print solder on the PCB, run through the reflow oven, then the SMD components soldering is done! It is so easy and quick.

  • SMT assembly is more cost effective

Since the SMT assembly has high efficiency, it is more cost-effective. As for PCB bare board, the PCB cost would be also a little cheaper since there are fewer drills. And the lead time is also better.

  • Easier to get a high yield with good quality
In SMT assembly, all the processes are done by equipment. So there is less chance of making mistakes. In addition, for seeking high-quality products, inspections are required. AOI inspection is one of the most commonly used inspections.

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    SMT Assembly’s Advantages and Disadvantages

    Every coin has two sides. There is no exception for SMT assembly. We have to take into consideration its advantages and disadvantages. Let’s introduce those points briefly for you.

    SMT assembly advantages

    Just need to drill fewer holes that would request less workforce time, and it can reduce electric product manufacturing costs in high volumes production, and reduce the unit price of the product.

    SMT technology allows the electronic component to take up less space on a printed circuit board, so the PCB size can become much smaller, and engineers can use those parts to make out smaller electronic items.

    Smaller sizes of the PCB also can enhance PCB assembly SMT deficiency in production. 1-2 hour though-hole work by PTH wave soldering, but if we use the SMT technology, it only takes 10-15 minutes to finish.

    Regarding the process of through-hole assembly, the wires are connected to the components through the holes in the PCB. In contrast, the process of SMT assembly is more simplified. It only requires the soldering of SMD components, which are soldered to the surface of the PCB.

    SMT assembly is an automated process operated by a pick and place machine, and the machine has software to control and is inspected by its software with equipment, so it would make fewer mistakes in production. But in the PTH assembly process, most of the PTH components need to be inserted in the PCB holes manually, so the chance of making mistakes is very high.

    SMT assembly disadvantages

    In the SMT PCBA line, a solder printing machine, pick and place machine, Feeders, AOI machine, reflow oven, X-ray, and a lot of other supportive equipment are needed. Among them, pick and place machines are very expensive, so an SMT line may cost more than 5M USD normally. Besides, building a clean room for SMT manufacturing is also very expensive.

    Just because SMT assembly uses automated machines with high speed, the workers must be very professional and also pay great attention to every detail of the whole production. If any design or procedure is incorrect and the machine remains operational in this condition, the product may be defective. That would cause a great loss in production. Besides, some factors may affect the whole SMT production, such as temperature stress, environmental stress, mechanical stress, etc. It is suggested that the mixed technology of SMT and THT should be used to address this problem.

    The Benefits SMT assembly Brings to the PCB Assembly Process

    Miniaturizing of components

    SMT allows the miniaturization of electronic products whereas the dimensions of antecedently used perforated insert parts will now not be reduced.

    More function on a small product

    SMT makes the function of electronic products more complete in a small area on the PCBs. And less Integrated Circuit (IC) with PTH assembly are used. 

    High speed and high efficiency

    The use of SMT can realize the batch production of products as well as the automation of production. After the adoption of SMT technology, the PCBA manufacturers rely on low cost and high yield to produce high-quality products to meet customers’ demands and strengthen market competitiveness.

    Adapt to trends in components development

    The use of SMT can adapt to trends such as the development of electronic components, the development of integrated circuits (ICs), and the diversified applications of semiconductor materials.

    Applications of SMT Assembly

    Nowadays, most PCB assemblies of advanced electronic products (computers and telecommunication products) are manufactured by the way of SMT assembly. The following industries are some examples of the uses of SMT assembly.

    8 Steps in SMT Assembly

    We know what is SMT PCBA and the advantages of SMT PCBA now. Next comes a detailed introduction to the processes of SMT assembly. In Viasion, we usually perform the following 8 steps in the SMT assembly process.

    1. Incoming material inspection

    All incoming electronic components need to be inspected first, including all the PCB parts and printed circuit boards. All the SMD PCB components should be in the same package, the same shape, and the same volume as the customer’s BOM. The PCBs should also be in good condition. For example, there is no oxidation, no deformation, etc. Components inspections are very important for surface mount technology PCB assembly. 

    2. Prepare before SMT assembly

    When all materials are ready, we need to prepare all the things connected with the SMT assembly. Stencils need to be done, PCBs and BGA chips need to be baked, pick & place files are ready to use, and suitable feeders are ready for the SMT assembly project.

    3. Add the solder paste

    4. Mount components with the help of a pick & place machine

    When the solder paste is printed on the bare PCBs and is of good quality after inspection. We need to use a high-accuracy pick-and-place machine to place the SMD components on the PCBs printed with the solder paste. We use a high-accuracy machine made by Yamaha to make sure the placement of components is highly accurate on the pads of the PCB.

    5. Solder components on the PCB

    Vapor-phase soldering and reflow soldering are regarded as the methods of soldering components on the PCB. They have different advantages to meet different conditions.

    As many experts point out, vapor-phase soldering applies to making samples or soldering-sensitive components. Vapor-phase soldering keeps heating the PCB until the solder paste is melted on the PCB. After the melt point cold down, the components would be fastened on PCB.

    Concerning the practical experience of mass production, reflow soldering technology is common. In the reflow soldering process, the nitrogen atmosphere is required and the printed circuit boards need to be put into it. The solder paste is melted by heated air as required. Then cool down the temperature of the PCB board, and the electronic components would be permanently fixed on PCB.

    In Viasion, we use reflow soldering. When our QA workers inspected the SMD PCB components placement is correct and in good condition, we will run PCBs into the reflow oven. We use 10 temperature zone reflow oven to make sure good welding. Of cause engineer need to adjust the profile to be exactly suitable for the project.

    6. 100% AOI inspection

    7. 100% Visual inspection

    8. QA inspection

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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.

    Is SMT Assembly the Same as SMD Assembly?

    Their definitions need to be clarified. SMD refers to parts mounted within the SMT assembly method whereas SMT could be a method within which AN automatic machine is employed to put electronic elements on the surface of the PCB. However, these two methods are the same. SMT assembly is instead referred to as SMD assembly. SMT assembly is employed for parts that have vital functionalities, like semiconductors and resistors, and capacitors. If the PCBs square measure with parts soldered by SMT assembly (or SMT soldering), they’re referred to as SMD PCB.

    What are the Differences between SMD, SMT, and PTH?


    Let’s begin with SMD. SMD is an abbreviation for surface mount devices. These types of devices are those electronic components used in the SMT manufacturing process. These component packages can be SOT, QFN, QFP, SOIC, BGA, PLCC, SOIC, etc. They are very commonly used for resistors, capacitors, and IC chips. But there are also a few types of components that are better to use PTH assemblies, such as connectors, and very big capacitors.


    Unlike SMD which means a product (surface mount component), SMT and PTH are categorized as two kinds of technology for assembling PCB. SMT is the acronym for surface mount technology. The process of mounting components on the PCB by the automatic pick & place machine is surface mount technology.


    PTH is short for plating through hole technology, which means soldering electronic components on the PCB by soldering the components' pins in the hole of the PCB. THT (Through hole technology) needs to drill holes in PCB  first, then use lead to mount electronic components on the PCB circuit board. Usually, THT components with long wires can be put on PCB through holes manually or by a special machine.

    Please refer to the following comparison between SMT and PTH:

    Items SMT assembly PTH assembly
    Equipment needed
    Pick & place machine, solder printing machine, AOI, X-RAY, reflow soldering equipment
    Wave soldering machine, automatic PTH line
    Components can be dissembled
    DIP, PGA, etc.
    Depends (good for Viasion)
    PCB size
    Better less than 25*30’’
    No limit
    PCB drills
    No need
    Normally 0.8-3.0mm
    PCB material
    Better rigid
    No limit
    From above, you can see the main disadvantages of PTH assembly (THT assembly):

    What Are Needed to Get a Quote for SMT Assembly?

    If you want to get a quotation for SMT manufacturing from an SMT manufacturer company, you need to answer the questions below, which SMT manufacturers need to know so that they can serve you well.

    After you answer the above questions, usually an SMT company can quote you the price rapidly.

    Why PTH Assembly is Still Popular in PCB Assembly?

    Although PCB SMT assembly has many advantages, many industrial machines still request the PCB board with through-hole components, why? Because through-hole technology enables the PCB to be more durable and to have power handling capabilities, heat tolerance, and physical connections. If the electronic device is under stress, it is better to use through-hole technology to handle it. At the design work, you should know it. We take connectors for example.

    What Is BGA assembly Technology?

    In SMT PCB assembly technology, BGA assembly is special. The full name of BGA is the ball grid array. It is considered a type of packaging IC (Integrated Circuit) on the PCB. All the soldering pads on the BGA are unable to see after we assembled the BGA on the PCB, so AOI and visual inspection in useless. So X-ray inspection is needed to check the assembly quality of BGAs, but of course, producing the BGA assembly correctly the first time is the key.

    How Does SMT Assembly Work?

    If you’re interested in learning how an electronic assembly facility operates, you’ve probably been wondering: How does SMT assembly work?

    Why Are We the Best SMT PCB Manufacturer?

    1. Viasion has a strong engineering team and a professional component procurement team. We are equipped with innovative technology and advanced production equipment (solder paste printing machine, pick & place machine, reflow oven, AOI detector).

    2. Viasion provides all-around services, including services in the pre-sales, in-sales, and after-sales phases. Our high-quality capability and attitude of service can provide solutions the first time when customers need them, and we actively solve every after-sales quality problem in the after-sales phase.

    3. Our production qualification can be reflected by the fact that we have passed certifications such as ISO9001, UL, RoHS/REACH, etc.

    4. Viasion has 16 years of manufacturing experience and has gained a good reputation, which fully demonstrates that we are reliable, trustworthy, and able to continue to develop well in this industry.

    Industries We Serve

    The industries we serve cover a wide range. The main industries are as follows.
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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.

    Why Are We the Best SMT PCB Manufacturer?

    In short, the pads of the PCB are printed with the appropriate amount of solder paste, then the chip components are placed on the printed circuit board at the specified location, and finally, the printed circuit board with the components attached is passed through a reflow oven to complete the soldering process.

    They are similar but a little different. Surface mount technology is the production technique of soldering electronic components on a printed circuit board. SMD is short for  surface mount devices, which means electronic devices use surface mount technology.

    We are very good at SMT soldering, PTH soldering and manual soldering; please refer to our SMT technology Capabilities as in this page:  https://www.viasion.com/pcb-assembly-capabilities/

    SMD means surface mount devices and SMT means surface mount technology, they are quite similar. SMD always means the devices using surface mount technology, such as SMT components and SMT PCB with surface mounting soldering.

    A normal SMT PCB assembly includes the following steps: solder paste printing – pick and place electronic components – run through reflow oven – quality inspections.

    SMT PCB assemblies are widely used in many applications, such as industry, telecommunications, testing, robotics, IoT, wireless and wifi, automotive, military, medical, aerospace, etc.