The Marvels of Double-Sided SMT Assembly

The continuing innovation makes it possible to fit more components into a smaller space precisely. But have you ever considered the intricate fabrication procedure of a double-sided SMT assembly? You’re in luck, then! This article will explore the protracted and complex process of making a double-sided SMT assembly and examine this technology’s numerous sectors and uses.

What is a Double-Sided SMT Assembly?

A double-sided SMT assembly is a printed circuit board (PCB) assembly with components attached to both sides of the Board. Since it enables the arrangement of more parts on one Board, this Board is frequently applicable when building complicated systems that demand a high component density level. However, double Sided SMT Assemblies are typically more challenging to manufacture than single-sided assemblies due to the complexity of routing and soldering components on both sides of the Board.

Assembly Process of a Double-Sided SMT Assembly

The fabrication process of a double-sided SMT assembly is a lengthy process that involves the following iterations:

1. Dispensing:

A double-sided SMT assembly’s assembly process begins with dispensing. With an automated dispensing device, this phase comprises accurately pouring a predetermined amount of glue or solder paste onto the Board. The dispensing device includes the nozzle, reservoir, and robotic arm. The robotic arm moves the nozzle across the circuit board while pouring solder paste or glue. This process is essential to guarantee that the Board receives the appropriate adhesive or solder paste quantity.

2. Component placement:

The following stage in the double-sided SMT assembly procedure involves placing the components on the substrate. Usually, a specific machine does this, putting the parts precisely on the substrate using a pick-and-place technique. It aligns the elements correctly, and the system ensures they are in the right spots. It may be necessary to manually insert the parts onto the substrate with tweezers or other equipment.

3. Curing:

Curing lets the glue or other liquid materials dry and solidifies after applying them to the Board. This step is essential to guarantee that the parts stay firmly attached to the Board. The pieces cling together, and the glue becomes stiffer during curing. Thermal curing and UV curing are the two types of curing. This process involves heating the Board to a specified temperature and leaving it for a set period to cure thermally. This method makes the glue firm. UV light exposure is necessary for UV curing, which causes the glue to harden. Depending on the glue type, the curing procedure may take several minutes.

4. Reflow Soldering:

Reflow soldering involves melting solder paste to form a link between the PCB and the components. First, the engineer must mix the little metal balls and flux to make solder paste. In this process, the solder paste covers the pads on the Board where the components will sit. Solder pastes melt when heated, forming a link between the element and the pad. The process of reflow soldering involves several steps, including preheating, melting solder paste, and cooling. The preheating process gradually elevates the Board’s temperature to a pre-set degree to prevent thermal shock to the components. It would help if you heated the Board to a higher temperature during the solder paste melting stage, which melts the solder paste and creates a bond between the components and the PCB. The Board then progressively cools during the cooling process to guard against component damage.

5. Cleaning:

Once the reflow soldering process is complete, the next step is cleaning. Cleaning is essential to remove any flux residues left on the Board after soldering. Over time, corrosion resulting from flux residues may degrade the performance of the Board. To clean the Board, the engineer rinses it in water or a cleaning solution like isopropyl alcohol. The cleaning solution dissolves and removes any flux residues from the Board.

6. Inspection:

After the cleaning procedure is over, examining the PCB comes next. This phase is crucial to ensure that everything connects correctly, that there are no shorts or openings, and that the assembly is error-free. Typically, the inspection process employs visual examination, electrical testing, and X-ray inspection.

7. Rework:

The final step in the double-sided SMT assembly process is reworking any components or boards with defects or issues. At this step, the engineer replaces any faulty panels or components, makes any repairs, and tests the gadget to ensure it is operating correctly. This stage is crucial because it guarantees that the device is working as intended and free from problems.

Applications of the Double-Sided SMT Assembly

The following are some of the industries that mostly employ the double-sided SMT assembly:

Medical Devices

Double-sided SMT assembly is widely applicable in medical equipment. Double-sided SMT assembly is now the method of choice for building medical equipment because it offers dependable, quick, and efficient assembly. From diagnostic tools to implanted medical devices, many applications use medical devices. Manufacturers of medical devices can benefit from double-sided SMT assembly in various ways. Double-sided SMT assembly increases the dependability and durability of products while decreasing the assembly time and costs for medical device makers. Also, the ability to utilize space more effectively through double-sided SMT assembly is crucial for medical devices that need to be compact and lightweight.

Consumer Electronics

Consumer electronics refers to devices like computers, televisions, mobile phones, and other home furnishings made for the general public. These products use double-sided SMT assembly to increase electrical components’ functionality while minimizing their footprint. In consumer electronics, double-sided SMT assembly enables higher circuit densities and better signal integrity by removing the requirement for gaps between components, which can cause unwanted noise or crosstalk, increasing performance. The size and weight of components also decrease during double-sided SMT assembly, improving their suitability for portable devices.

Industrial Control Systems:

Computer-based industrial control systems (ICS) help monitor and manage operations in facilities, infrastructure, and industrial settings. ICS is often suitable for providing safety, security, and emergency response, as well as for regulating and monitoring production processes, such as manufacturing and distribution. The potential of double-sided SMT assembly to provide dependable, cost-efficient solutions makes it a popular option for industrial control systems. Components, including integrated circuits, transistors, resistors, capacitors, and diodes, can sit on both sides of the Board owing to the double-sided assembly technique. As a result, the system operates better and makes greater use of available space. Moreover, double-sided SMT assembly might enable the use of smaller components and lessen the amount of wiring required, improving heat control and lowering costs.


Manufacturing telecommunications goods is a perfect application for double-sided SMT assembly. These items need more compact, challenging-to-handle components since they are portable. Utilizing double-sided SMT assembly enables the installation of components on both sides of the Board, increasing the component density and enhancing the product’s overall performance. Moreover, this kind of assembly offers more freedom in component architecture, allowing for the construction of circuits with fewer routes, quicker signal transmission, and enhanced signal integrity.


In conclusion, double-sided SMT assembly is a valuable technique in producing contemporary electronics. It is appropriate for various industries, including medical, consumer electronics, industrial control systems, and telecommunications, since it enhances component density while reducing size and weight. It is a complex and drawn-out procedure, but it is worthwhile to produce dependable, economical products that maximize available space.

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