PCBMay Provides Professional PCB Assembly Process for Your Project

At PCBMay, we will provide discussion on the step-by-step PCB assembly process, in fact, it depends on the specific type of PCB assemblies such as through-hole and surface mount, the steps may vary slightly, you will find more details here.

  • Over 12 years PCB assembly process manufacturing experience
  • Over 50 technical engineering to support your project
  • No MOQ for new orders, even one piece
  • 100% E-test and AOI inspection
  • No set-up fees & no stencil charges for repeat orders
No.ItemProcess Capability Parameter 
1Order Quantity≥1PCS
2Quality GradeIPC-A-610
3Lead Time24 hours expedited service can be offered. 3- 4 days normally for PCBA prototype orders. We will give you an accurate lead time when we quote for you.
5Board TypeRigid PCB, Flexible PCB, metal core PCB
6Min Package01005 (0.4mm*0.2mm)
7Max PackageNo limit
8Mounting Accuracy±0.035mm(±0.025mm)  Cpk≥1.0 (3σ)
9Surface FinishLead/Lead-free HASL, Immersion gold, OPS, etc.
10Assembly TypesSurface mount (SMT), Through-hole (DIP), Mixed Technology (SMT & Thru-hole)
11Component SourcingTurnkey (All components sourced by PCBMay), Partial turnkey, Kitted/Consigned
12BGA PackageBGA Dia. 0.14mm, BGA 0.2mm pitch
13SMT Parts PresentationCut Tape, Partial reel, Reel, Tube, Tray, Laser-cut Stainless Steel
14Cable AssemblyWe supply custom cables, cable assemblies, wiring looms/harnesses and power leads for various industries including automotive, security, mining, medical, and entertainment.
15StencilStencil with or without frame (offered free by PCBMay)
16Quality InspectionVisual inspection; AOI checking; BGA placement – X-RAY checking
17SMT Capacity3 Million~4 Million Soldering Pad/day
18DIP Capacity100 Thousand Pins/day
PCB Assembly Production line

Releted PCB Assembly

Why Choose PCBMay for Your PCB Assembly Process

As a reliable PCB assembly manufacturer in China, PCBMay strictly controls each PCB assembly process. From Pick & Place, wave & SMT soldering, quality check, and final test.

Are you looking for a leading PCB assembly supplier? PCBMay is the right place for you and all of our PCB assembly processes are in-house.

Please send your quote to us right now, we will offer the quotation immediately.

PCB Assembly Process: The Ultimate FAQ Guide

Printed circuit board (PCB) usually refers to the substrate used to assemble electronic parts.

It is a printed board that connects dots and prints components on a common substrate according to a predetermined design.

Its main function is to connect various electronic components to a predetermined circuit to play the role of relay transmission. Because almost all electronic devices use printed circuit boards.

PCB Assembly Process

PCB Assembly Process

Therefore, it is often called “Mother of Electronic System Products”.

What is PCB Assembly Process?

PCB assembly is the process of assembling electronic components and other products onto a printed circuit board.

A PCB with components mounted on is called an assembled PCB and the manufacturing process is called PCB assembly or PCBA for short. The copper lines on bare board, called traces, electrically link connectors and components to each other.

PCB Assembly process consists of component assembly and mechanical assembly.

The components are usually soldered onto a PCB. Installation by wire welding and gluing on conductive glue is also used.

The installation of components can be carried out manually or automatically. In modern production, the most common technology is surface mounting, and through-hole mounting is also widely used.

After component installation, additional operations such as cleaning, electrical inspection, conformal coating, pouring, additional marking can be performed.

During mechanical assembly, mounting elements, cooling systems, screens, and other mechanical products are installed on the board.

PCB Assembly Process

PCB Assembly Process

Contemporary PCB Assembly Process

At present, the mainstream PCB Assembly process is ” SMT (Surface Mount Technology) “, which first prints solder paste on the blank board, then mounts the electronic components on the PCB and flows it back Soldering in a high-temperature furnace (Reflow), the components are pasted on the PCB through solder paste soldering.

A small number of PCB assemblies will use” Wave Soldering “technology.

Generally speaking, there will be some electronic components that are heavy or need to withstand external force.

These components are not technically and cannot be made into SMD components.

Or if the price of SMD components does not meet market expectations or some components that must be subjected to external force when used by the end customer.

They will be designed as through-hole components, that is, the plug-in (DIP), and then flow through The wave soldering furnace solders the components to the PCB.

There is also simultaneous hybrid soldering (SMT) and wave soldering(wave soldering)technologies to achieve the design of component soldering to the PCB.

PCB Assembly Process

PCB Assembly Process

What is PCBA Board? 

PCB Assembly process can basically be regarded as a finished product (Finished Goods), because some factories will produce PCBA for shipment, such as selling computer motherboards alone.

Basically, PCB can only be regarded as a component, PCB is an important component in the whole PCBA, but it cannot represent PCBA.

because PCB has to be soldered with an integrated circuit (IC), resistor (resistor), capacitor (capacitor), Inductor, connector, and other parts can be finished products, so PCB should only be regarded as a kind of part.

In short, circuit board prototyping is very complicated. Each different process requires different components, and PCB components can be said to be one of the most important components.

After all, your circuit board is meaningless if it is not assembled correctly!

Although rigid and flexible printed circuit boards have been common since the development of the automatic PCB Assembly process in the mid-1950s, the PCB industry has mostly changed its manufacturing method to SMT.

Six Major Steps to PCB Assembly Process

First: Solder paste stencil solder pastes Before adding any components to the circuit board, the engineer must add a layer of solder paste.

After placing the screen on the circuit board, the engineer will squeeze a small amount of solder through the hole on the screen to ensure that the solder only touches the component pads.

However, this can be tricky because there must be the same amount of solder on each pad.

The idea is very simple, the solder paste is applied to the component pads and can be applied through the solder mesh.

Solder paste stenciling is the process of using a stencil made out of metal or a polymer to quickly apply solder paste to all of the pads on your bare board.

This stencil contains a bunch of holes in it, which represents all of the SMD footprint pads on your board layout.

Second: Pick and Place Once the solder is dry and firm, the appropriate components will be picked and placed on the PCB.

The solder paste has enough tension to keep it safe until the engineer shakes the circuit board, but sometimes, small dots can be used as a backup.

A pick and place (PNP) machine is a robotic assembly device that uses a vacuum to lift a component off of a piece of tape, rotate it to the right orientation, then place it on a circuit board.

It takes a few hours to set up a machine to build the assembly, but once everything is running, it is very fast.

PCB Assembly Process

PCB Assembly Process

Third: Reflow Soldering When everything is in place, the circuit board will pass through the soldering machine.

Reflow soldering is a process in which a solder paste (a sticky mixture of powdered solder and flux) is used to temporarily attach one or thousands of tiny electrical components to their contact pads, after which the entire assembly is subjected to controlled heat.

Fourth: Inspection Check and Quality Control  This may be the most important step in PCB assembly.

The engineer will manually inspect each board to ensure that all joints and components are in the required locations and in normal working condition.

Quality control refers broadly to the process of managing product quality to meet the desired standard(IPC class II).

Inspection is only a part of this process used to identify quality defects in products.

Inspection can help you find any defects earlier in production before they affect the majority of a shipment. There’re manual checks, automatic optical inspection, and X-ray Inspection.

Five: Through-Hole Component Insertion Through-hole technology (also spelled “thru-hole”), refers to the mounting scheme used for electronic components that involve the use of leads on the components that are inserted into holes drilled in printed circuit boards (PCB).

Soldered to pads on the opposite side either by the manual assembly (hand placement) or by the use of automated insertion mount machines.

Five: Final Inspection and Functional Test At this point, it’s time to play with your board and test it!

After the soldering step of the PCBA process is finished, a final inspection will test the PCB for its functionality.

This inspection is known as a “functional test”. The test puts the PCB through its paces, simulating the normal circumstances in which the PCB will operate.

Power and simulated signals run through the PCB in this test while testers monitor the PCB’s electrical characteristics.

PCB Assembly Process

Why is PCB Manufacturing so Important to Realize Microelectronic Assembly?

Because the PCB in microelectronic assembly is more special, it includes the high precision required to place the bare chip on the circuit board, and the high cleanliness of the circuit board before and after connecting the chip.

In fact, the PCB Assembly process is the basis for the success of the entire microelectronics assembly process and it is very important.

For companies that have just entered this field, manufacturing plants that produce PCBs for microelectronics assembly should at least obtain ISO9001 certification to have the infrastructure to produce high-quality PCBs.

If the PCB manufacturer also has other certifications such as ISO13485, AS9100, and certain military/aerospace certifications, so much the better.

In addition to these certifications, it is also required to perform well in three major areas: the coplanarity of circuit boards and substrates, process control, and verification.

Simply put, coplanarity means that the surface of the PCB or carrier is 100% uniform.

PCB Assembly Process

PCB Assembly Process

The surface coating that appears in the picture can determine which coating is completely uniform for microelectronic assembly.

Here you will find many quick questions and answers about PCB Assembly Process, don’t hesitate to contact us, our email is sales@pcbmay.com.

How Do I Mount A Component In PCB?

A common way of soldering SMT components automatically is “Over Reflow Soldering”.

A solder paste containing both flux and solder is then applied to the solder pads before the components are placed on the PCB.

The PCB is then heated in an oven such that the solder in the paste melts.

Do You Offer RoHS-Compliant Assemblies?

Yes. We do offer RoHS-compliant assemblies.

Do You Offer Testing And Inspection Services?

Yes. We do offer different types of testing and inspection services.

What Are The Different Testing Services Provided By You?

All the PCBs undergo testing and inspection in every phase of assembly. The PCB assemblies are subjected to the following types of testing:

  • X-ray Testing: This testing is performed as a part of the standard assembly process on Ball Grid Arrays (BGAs), Quad-flat-No-lead (QFN) PCBs, and more.
  • Functional Testing: In this, we perform the functionality check on the PCB. This is performed to ascertain if the PCB is working according to the requirements specified by the client.
  • In-Circuit Testing: As the name suggests, this testing is performed to check the joint failures or shorts.

What Are Your PCB Assembly Standards?

IPC-A-610 Class 2.

Is There Any Minimum Order Quantity?

No, we can produce 1 to 10,000 pieces, what’s more, there is also no minimum order surcharge or additional fees


Finally, after completing the PCB Assembly process, it is verified, which is a key step to ensure accurate assembly.

The use of highly advanced and sophisticated tools such as Keyence digital microscopes is ideal for precise measurement, inspection, and verification of chip connection and wire bonding applications.

These verification functions are necessary to detect defects in the entire manufacturing process and such defects cannot be detected with conventional inspection tools.

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