Your Reliable SMT PCB Assembly Manufacturer in China

PCBMay is a professional SMT PCB assembly manufacturer in China, which provides rapid surface mount assembly service, also provids surface mount & SMT assembly services to produce PCBs, electronic circuit boards, and other surface mounted devices.

  • Over 12 years SMT PCB assembly manufacturing experience
  • Files receive full CAM review prior to manufacturing
  • No MOQ for new orders, even one piece
  • 100% E-test and AOI inspection
  • 7/24 sales and engineering tech support
No.ItemProcess Capability Parameter
1Order Quantity≥1PC
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 SMT PCB Assembly

PCBMay: Your Premier SMT PCB Assembly Supplier in China

Are you looking for a reliable SMT PCB assembly manufacturer? PCBMay is your best choice.

We at PCBMay offer high-quality surface mount SMT PCB assembly service and reasonable prices with express delivery time.

With automatic assembly production lines, we can help you to the assembly from double-sided to multilayer PCBs.

PCBMay is not only just a leading PCB fabrication manufacturer but also a one-stop provider for all your PCB assembly requirements.

We provide different kinds of SMT PCB assembly to customers all around the world.

From components sourcing, PCB fabrication, SMT PCB assembly to final testing, all processes are in-house.

Our PCB assembly plant has a workshop of 8,000 square meters and over 500 workers. There are 6 fully automatic SMT production lines, 3 wave soldering production lines, 5 assembly lines, and auxiliary testing and aging facilities.

Whoever you are an electrical engineer, a purchasing manager, a project manager, or a product designer looking for SMT PCB assembly, PCBMay will be your excellent SMT PCB assembly supplier in China.

Send us your Gerber data and BOM list files, you will get an awesome product.

SMT PCB Assembly: The Ultimate FAQ Guide

SMT stands for Surface Mounted Technology, which is one of the most popular technologies and processes in the electronics assembly industry.

Electronic circuit surface assembly technology, called surface mount or surface mount technology.

SMT Assembly

SMT Assembly

It is a kind of leadless or short lead surface mount component (SMC/SMD for short) mounted on the surface of the Printed Circuit Board (PCB) or other substrates through reflow soldering or dip soldering Circuit assembly technology that is welded and assembled by other methods.

Under normal circumstances, the electronic products we use are designed by PCB plus various capacitors, resistors, and other electronic components according to the designed circuit diagram, so all kinds of electrical appliances need a variety of SMT chip processing techniques to process

What is SMT PCB Assembly?

In recent years, printed circuit boards have evolved with increased demand for more functionality, smaller dimensions, and added utility.

Modern PCB design provides for two main methods of component mounting: lead-through and SMT Assembly.

Lead-through (through) wiring is the process by which component leads are placed into drilled holes on a clean printed circuit board.

This process was standard practice until the advent of surface mount technology (SMT) in the 1980s when the use of through-holes was expected to end entirely.

However, despite severe declines in popularity over the years, lead-out technology has proven to be robust in the SMT era, offering a range of benefits and customized applications.

PCBMay works with both SMT Prototype PCB Assembly and Low-Volume PCB  Assembly Production runs, using both manual and automatic SMT assembly processes.

SMT Assembly

SMT Assembly

We perform single and double-sided placement of all component types. With us, you don’t have to think about the details of the production yourself and can focus on your design.

What are the SMT PCB Assembly Processes?

1, Placement(Curing)

Its function is to melt the patch glue so that the surface assembly components and the PCB board are firmly bonded together.

The equipment used is a curing oven, located behind the placement machine in the SMT production line.

2, Reflow Soldering

Its function is to melt the solder paste so that the surface assembly components and the PCB board are firmly bonded together.

The equipment used is a reflow oven, located behind the placement machine in the SMT production line.

3, SMT Assembly Cleaning

Its function is to remove the solder residues such as flux that are harmful to the human body on the assembled PCB.

The equipment used is a washing machine, and the location may not be fixed, it may be online or offline.

4, SMT Assembly Inspection

Its function is to inspect the welding quality and assembly quality of the assembled PCB board.

The equipment used includes a magnifying glass, microscope, online tester (ICT), flying probe tester, automatic optical inspection (AOI), X-RAY inspection system, functional tester, etc.

5, SMT Assembly Rework

Its function is to rework the PCB boards that have failed to detect faults.

The tools used are soldering iron, rework station, etc. Configured at any position in the production line.

As you know, there’re some small problems during the production, so it’s the best way to rework the assembly by hand.

6, SMT Assembly Packing

PCBMay offers assembly, custom packaging, labeling, clean room production, sterilization management, and other solutions for a complete, customized solution for your company’s needs.

By using automation to assemble, pack and validate our products we can offer our customers a more reliable and efficient production process.

What are the advantages of SMT PCB Assembly?

  • Surface-mount technology (SMT) permits the creation of smaller PCB designs by allowing components to be placed closer together on the board. This means devices can be designed to be more lightweight and compact.
  • The SMT process is faster to set up for production than its counterpart, through-hole technology because it does not require the circuit board to be drilled for assembly. This also means it has lower initial costs.
  • Printed circuit boards created with the SMT process are more compact, providing higher circuit speeds.
  • Its combination of high-end components allows for multitasking.
  • Components can be placed on both sides of the circuit board and in higher density – more components per unit area and more connections per component.
  • PCBs flow seamlessly from fabrication to assembly.
  • SMT provides stability and better mechanical performance under vibration and shaking conditions.
  • The surface tension of the molten solder pulls components into alignment with solder pads, automatically correcting small errors in component placement.

SMT Assembly

SMT Assembly

There are Six Types of SMT PCB Assemblies

There are six general types of SMT assembly in the electronics industry, each with a different manufacturing order.

There is a special standard that presents the main types of assemblies, broken down by class.

Below we will consider the main options for placing components on the board, used by developers.

SMT Assembly SMT Top Side Only

Figure: 1 – Type 1B: SMT Top Side Only

This type is not generic as most designs require some DIP components. It is called IPC Type 1B.

The order of the process: application of solder paste, installation of components, soldering, rinsing.

SMT AssemblySMT Tops and Bottoms

Figure: 2 – Type 2B: SMT Tops and Bottoms

On the underside of the board are chip resistors and other small components.

When wave soldering is used, it will be remelted by the upstream (side) wave flow of the solder.

Placing large components on both sides, such as PLCCs, increases production costs because the components on the bottom side must be mounted on a special conductive adhesive. This type is called IPC Type 2B.

The Order of the Process:

  • Solder paste application
  • Component installation
  • Soldering
  • Bottom side rinsing;

Applying solder paste to the top of the PCB, installing the components,re-soldering, rinsing the top side.

Special type: SMT top side in the first case and top and bottom side in the second, but PTH is only the top side.

SMT Assembly

Figure: 3

This installation method is used when there are DIP components in the SMT assembly.

The process involves placing DIP components to be inserted into holes prior to SMT soldering.

When using this method, the unnecessary operation of wave soldering or manual soldering of PTH components is removed, which significantly reduces the cost of the product.

The first requirement is the ability of the components to withstand secondary soldering. In addition, board hole dimensions, pads, and stencil geometry must be precisely aligned to achieve a good seal.

The board must have plated through holes and can be single-sided or double-sided, that is, components can be placed both from the top and from the bottom.

A mandatory requirement when using this method is the presence of plated through holes.

Single-Sided PCB Processing Order:

  • Application of solder paste
  • Installation of SMT components
  • Installation of PTH components
  • Soldering
  • Rinsing the top side

Processing Order of Double-sided PCB:

  • Solder paste application
  • Installation of SMT components
  • Reflow
  • Bottom side rinsing

installation of PTH components, soldering, flushing of the top side.

SMT Top Side only and PTH Top Side Only

Figure: 4 – Type 1C: SMT Top Side only and PTH Top Side Only

This method is a mixed assembly technology. All SMT and PTH modules are installed on the top side of the board.

It is possible to mount some PTH components on the top side of the board where SMT components are placed to increase density. This SMT Assembly-type is called IPC Type 1C.

The Order of the Process:

  • solder paste application
  • installation
  • Reflow
  • rinsing of the top of the SMT
  1. Automatic DIP setting, then axis components (such as LEDs)
  2. Manual installation of other components

Wave soldering of PTH components, flushing.

SMT Top and Bottom Side or PTH on Top and Bottom Side

Figure: 5 – Type 2C: SMT Top and Bottom Side or PTH on Top and Bottom Side

Mounting surface mount and DIP components on both sides of the board is not recommended due to high assembly costs.

This design can require a lot of manual soldering. Also, automatic installation of PTH components is not applied due to possible conflicts with SMT components on the underside of the board.

This SMT Assembly-type is called IPC Type 2C.

The Order of the Process:

solder paste application, installation, soldering, washing of the upper side of the SMT;

  • Applying special conductive glue through a stencil, installing, fixing SMT
  • Automatic setting of DIP and axial components
  • Masking the entire underside of PTH components
  • Manual installation of other components
  • Wave soldering of PTH and SMT components, flushing
  • Manual soldering of the bottom side of the PTH components

SMT Bottom side Only or PTH Top Side Only

Figure: 6 – Type 2C: SMT Bottom side Only or PTH Top Side Only

This type assumes the placement of the surface mount on the bottom of the board and PTH on the top.

It is also one of the very popular types of accommodation because allows you to significantly increase the density of components.

The type is called IPC Type 2C.

The Order of Processing (there are no PTH conflicts on the lower side):

Stencil application of glue, installation, glue drying on the underside of SMT;

  1. Automatic DIP setting, then axial components;
  2. Manual installation of other components
  3. Wave soldering of PTH and SMT components, flushing
  4. Alternative processing order (PTH conflicts on the downside)
  5. Automatic DIP setting, then axial components
  6. Spot glue application (dispensing method), installation, glue drying on the underside of SMT
  7. Manual installation of components
  8. Wave soldering of PTH and SMT components, flushing.

SMT Top and Bottom Sides or PTH on Top Side Only

Figure: 7 – Type 2Y: SMT Top and Bottom Sides or PTH on Top Side Only

This type allows surface-mount components to be located on both sides of the board, and DIP components only on the top.

This is a very popular SMT Assembly-type for developers to place high-density components.

The underside of the SMT components remains free of the axis elements and DIP component legs.

For example, you cannot place microcircuits between the pins of a DIP component.

Process flow (without placing surface mount (SMT) between the feet of the hole mount (PTH) components on the underside of the board):

  • Solder paste application, installation, soldering, rinsing the upper side of the SMT part;
  • Stencil application of glue, placement, drying of SMT glue on the underside;
  • Automatic installation of DIP and then axial components
  • Manual installation of other components
  • Wave soldering of PTH and SMT components, flushing;

SMT Assembly

SMT Assembly

Alternative process order on the underside of the surface mountable (SMT) board, the components are located between the pins of the through-hole mount.

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