PCBA Manufacturing

PCBA Definition

A PCBA is a finished PCB assembly that includes all of the electronic components required to make the board function as intended, whereas PCB refers to a blank board.

The term “printed circuit board assembly,” or “PCBA,” refers to the component placement on the PCB or bare board. The circuit board is built with numerous electronic components before being soldered into place.

Methods of PCBA Manufacturing

There are three methods of Surface Mount Technology (SMT) Assembly, Thru-Hole Technology (THT) Assembly, Mixed Assembly Technology. They are used to manufacture different design of PCB assembling board.

smt PCB Assembly 2

Surface Mount Technology (SMT) Assembly


Electronic circuits are built using surface-mount technology (SMT), in which the components are adhered with solder paste directly to the surface of printed circuit boards (PCBs).

SMT assembly process:

Step 1: Printing soldering past:

A solder paste printer is used to apply solder paste to the board.

A template, stencil, or solder screen ensures that solder paste can be applied precisely to the intended locations for mounting components.

Step 1:Component placement

The PCB will automatically be delivered to a pick-and-place machine after coming out of the solder paste printer, where components or ICs will be installed on the appropriate pads thanks to the tension of the solder paste.

Through component spools inside the machine, components are installed to PCB boards.  To supply parts to the machine, which will quickly stick parts to the board, component reels containing parts rotate.

Step 1:Reflow soldering for solidified components

The board travels through a 500°F, 23-foot-long furnace (reflow oven) after every component has been installed.

It is necessary to heat the solder paste until it melts and makes solid, dependable connections between the board’s surface and the components. Reflow ovens are used to achieve this, heating the solder to the right temperature and then allowing it to cool till it solidifies once more.

SMT assembly advantage

Surface mounting features a high level of automation compared to through-hole mounting, which lowers labor costs and boosts output. In comparison to equivalent through-hole parts, SMDs can be half to a quarter the size, weight, and cost.

through hole PCB Assembly

Through Hole Technology (THT) Assembly

Pin-through-hole (PTH) components are placed into electronic circuits using the Through Hole Technology (THT) technique, which involves drilling holes into printed circuit boards (PCBs).

The ends, or leads, are then connected to pads on the opposing side using wave soldering or reflow soldering tools and molten metal solder. Additionally known as through-hole assembly, this method.

Through Hole Technology (THT) assembly process


Step.1 placing Components

Engineers working in the field manually complete this procedure. Engineers must rapidly and accurately insert components on the PCB according to the client’s PCB design files.

To ensure high-quality finished goods, component placement must adhere to the rules and operation criteria of the through-hole mounting procedure.

Step.2 Inspection

Once component placement is complete, the board is put in a transport frame that matches it, where it will be automatically checked to see if the components are correctly plugged in.

If component placement problems are discovered, it is also simple to have them quickly fixed. After all, in the PCBA process, this occurs before soldering.

Step.3  Wave Soldering

Now, carefully solder the THT components to the circuit board. In the wave soldering system, the board glides gently over a high-temperature, 500°F-plus wave of liquid solder.

Prons and cons of Through Hole Technology (THT) assembly

Although through-hole mounting offers stronger mechanical bonding than techniques used in surface-mount technology, the additional drilling needed to build the boards raises their cost. Since the holes must pass through all layers to the other side, it also reduces the amount of space that can be used for routing signal traces on multilayer boards. For these reasons, through-hole mounting is typically saved for larger components that need extra mounting strength to withstand physical stress, like electrolytic capacitors or semiconductors in big packages.

Mixed Assembly Technology

The complexity of electrical items is rising as a result of recent innovations. These sophisticated electrical gadgets require PCB boards that are more intricate, integrated, and compact.

It is nearly impossible for PCBAs with just one kind of component to carry out such intricate duties.

Consequently, a mixed technology board with both SMD and through-hole components will be needed for this application.

These types of boards combine surface mount technology and through-hole technology since they contain both SMD and SMD components.

However, soldering is a challenging procedure that is frequently impacted by an excessive number of factors. Therefore, improving the order in which surface mount technology and through-hole technology are introduced becomes extremely important.

There are three types of Mixed Assembly: Double Side Mixed PCB Assembly, One Side SMT & One Side THT PCB assembly,  Single Side Mixed PCB Assembly. Those assembly technology involving process are little bit different.

Double Side Mixed PCB Assembly

There are two options for double-sided mixed assembly methods: PCBA with adhesive application and PCBA without adhesive.

The cost of PCB assembly as a whole is increased by the use of adhesives. Additionally, this PCBA technique requires three heating cycles, which tends to result in low efficiency.

Mixed PCB Assembly steps:
1. Solder paste printing
2. SMD parts placement
3. Reflow Soldering
4. Flipping
5. Smt Adhesive
6. SMD Parts placement
7. Solidification
8. Flipping
9. THT component placement
10. wave soldering.

PCBA and PCB difference and relationship

The end products of the same general process are PCB and PCBA, which are two distinct processes. A PCBA is a finished assembly that has all the components needed for the board to perform as needed for the desired application, as opposed to a PCB, which is a blank circuit board with no electrical components connected. A PCBA is prepared for usage in an electronic device when a PCB is not yet operational.

Due to the numerous components and steps needed in PCB assembly, generating a finished PCBA is more difficult than producing a blank board. A PCBA is also more expensive to construct than a blank PCB. However, in order to construct a finished board, both procedures are required. Without a PCB, you cannot make a PCBA. The first step in the process is PCB manufacture, and PCBA manufacturing builds on that first step.

The packaging of PCBs and PCBAs is another distinction. PCBAs need compartmental or anti-static packaging, whereas PCBs are commonly wrapped using vacuum packaging.

PCBA assembly

How can we sure the quality of PCBA that we manufature for you?

To control the PCBA quality, we can provide you test methods such as Functional testing, X-Ray inspection, Burn-in testing, Automated optical inspection (AOI), Flying probe testing, In-circuit testing. These testing methods usually can be combinated together to sure the quality more reliable.

In addition to turnkey PCB assembly, board-level and completed box construction assembly, SMT and thru-hole technology, and everything in between, we also offer skilled hand assembly. Our FDA-registered and ISO 9001-certified factory can produce high-quality PCBA for you. Click here to find out more information about our company.