One-Stop PCB Assembly Services | PCBA EMS Manufacturing

"One-stop PCB assembly services include PCB fabrication, component sourcing, PCB assembly, PCBA testing, and value-added services such as conformal coating."
PCB assembly

PCB Assembly Services from PCBONLINE

conformal coating for PCB assembly
  • Printed circuit board assembly, or PCB assembly, is a process of surface-mounting and through-hole-mounting electronic components onto the PCB to make it a PCBA. A PCBA is a module board that can further assemble with other parts to be an end product or system.
  • PCBONLINE is a PCBA contract manufacturer. We provide PCB fabrication, component sourcing, PCB assembly, and electronics value-added services from prototypes to assembly. Our PCB assembly services cover PCB design for manufacturing (DFM) and test (DFT), PCBA design for assembly (DFA), and box build design for excellence (DFX) for free.
  • PCBONLINE's electronic manufacturing service (EMS) factory for PCB assembly is dust-free. Every process has a group member specialized in spot check quality control (QC), which is independent of our QC system to prevent poor quality PCBAs. The PCB assembly processes include:
  • PCB fabrication: PCBONLINE provides PCB manufacturing for all kinds of PCBs from prototypes to massive manufacturing, such as FR4 PCBs, flexible PCBs, rigid-flex PCBs, MCPCBs, ceramic PCBs, etc. All you need is to send your Gerber.
  • Surface-mount technology (SMT) assembly: SMT is an automatic PCB assembly process. It includes solder paste printing, solder paste inspection (SPI), placing SMDs, x-ray inspection, visual inspection, reflow soldering, and automatic optical inspection (AOI). If the PCBA has two mounting sides, it returns the start of the SMT line to mount the second side.
  • Through-hole mount (THT) assembly: THT is a half-auto PCB assembly process. The THT components are inserted through holes by hand or machine, and then the PCBA is preheated and wave-soldered. At PCBONLINE, we use the German Ersa selective wave soldering machines to ensure soldering quality.
  • First Article Inspection (FAI): PCBONLINE offers the FAI for PCB assembly. We manufacture five PCBAs and randomly pick up one piece to inspect every component on it. After that, an FAI report is generated for you to review. Only with your approval, shall we start massive PCBA manufacturing. The FAI avoids possible economic losses of bulky orders.
  • After PCB assembly, PCBONLINE also provides PCBA value-added services in the post-assembly stage, and they include:
  • Functional testing: This is a power-on self-test. The PCBAs are put on a jig one by one to test the power-on effect. At PCBONLINE, the functional test is only $0.075 per piece. And for massive PCBA manufacturing, it is free.
  • Conformal coating: PCBAs are coated with urethane/polyurethane to protect the boards from dust, moisture, chemical, vibration, and high temperatures and lengthen the lifespan. At PCBONLINE, we adopt the electrostatic spraying method for conformal coating, which achieves the best flatness.
  • IC programming: IC programming means downloading a program into the ICs. At PCBONLINE, we don't collect your program information. If you want, we can buy a temporary Aliyun account for you to transfer your program to the ICs directly without downloading it to our computer.
  • Burn-in test: A burn-in test is also called a thermal aging test. In a programmable temperature chamber, the PCBAs continuously work for 48 to 168 hours to see whether they are reliable for long-time working.
  • Box-build assembly: Box-builds are the end products. We can assemble the PCBAs with enclosures and label them in your brand. All you need is to send us your enclosure design which matches the PCBA.
  • PCBONLINE is an EMS PCBA manufacturer, and our advanced PCB assembly factory is located in Shenzhen. We serve original equipment manufacturers (OEMs), research institutes, and business makers around the world. For more than 24 years, we have had rich experiences in PCB assembly for automotive, industrial, defense, medical, computing, communications, agricultural, and consumer electronics. You can send your Gerber, BOM, and pick-and-place file to to quote.

Printed Circuit Board Assembly Testing

printed circuit board testing
Circuit board assembly testing covers on-line PCBA tests and PCBA tests in the post-assembly stage. The EMS PCBA manufacturer PCBONLINE has a rigorous QA system with comprehensive PCBA tests.
On-line PCBA tests happen on the SMT and THT assembly lines, and they are:
SPI: SPI happens after solder paste printing on PCBs and before SMDs placing on boards. An SPI machine scans the solder paste and compares its shape, size, thickness, and position with the pre-input parameters. The solder paste thickness must fall within the range of ±0.03mm of the SMT stencil thickness.
X-ray: If PCBs are mounted with BGAs, they should be x-ray scanned before reflow soldering. An X-ray machine inspects connections between the PCB and BGAs to ensure solderability.
AOI: After reflow soldering, an AOI machine scans the PCB/PCBA surface and compares it with the pre-input parameters to detect PCBA defects, such as solder bridges, voids, tombstones, etc. At PCBONLINE, the AOI is 3D, which covers more surfaces than the 2.5D AOI.
Visual inspection: Before reflow soldering and after wave soldering, and before and after wave soldering, there are QC members who visually check the PCBA carefully to further ensure the quality.
PCBA tests in the post-assembly stage not only include the functional test and burn-in test but also the application simulation test.
Application simulation test: After the PCBA is installed with the enclosure to be an end product, we simulate its use environment and let it work for a long-time period to check its working effect.
The one-stop PCBA manufacturer PCBONLINE not only fabricates and assembles printed circuit boards but also tests them until you are satisfied with the end products. Our circuit board assembly is medical and military-grade, which meets the highest quality standard requirements.

How to Order PCB Assembly from PCBONLINE

  • Currently, our online quote system doesn't support uploading a bill of materials (BOM). To order PCB assembly services, please send your Gerber, BOM, and pick-and-place file to Or you can upload your Gerber on PCBONLINE's online quote page to order PCBs, and when PCBONLINE contacts you, you send the BOM and pick-and-place file and tell them that you need PCB assembly, and your specialized PCBONLINE customer support specialist can assist you to pay online. If you need IC programming, please send the cable adapter or let us buy it.
  • When we receive your inquiry, we will review your documents and give you a PCB assembly quote. Your PCBONLINE customer support specialist will follow up with you throughout the project.
  • The PCBs and SMT stencils will be manufactured in our advanced PCB manufacturing bases, the electronic components will be sourced from original factories and first-level suppliers audited by us and have long-term cooperation with our EMS factory, and the PCBs will be mounted with electronic components and value-added at our EMS PCBA factory in Shenzhen.
  • In shipping, FedEx, UPS, and DHL are available. We have a collaboration with FedEx, and sea shipping is very cheap.

Printed Circuit Board Assembly Capabilities

PCB assembly services

Applications of PCB Assemblies from PCBONLINE

  • ● PCB assemblies are semi-manufactured goods and play key functions in almost all electronic devices
  • ● PCBA manufacturing that follows IPC-A-610 Class 1 serves general and consumer electronics
  • ● PCBA manufacturing that follows IPC-A-610 Class 2 serves communication, industrial electronics, and complex commercial devices that require a long lifespan
  • ● PCBA manufacturing that follows IPC-A-610 Class 3 serves medical electronics, aerospace/aviation controllers, precision instruments, and high-reliability devices that work in harsh environments
  • ● Aluminum, ceramic, and copper-based PCB assemblies are used for electronic devices that require much thermal dissipation
  • ● Rigid-flex and flexible PCB assemblies can be used for electronic devices that have a compact space and require flexibility, such as mobile phones, laptops, satellites, gastroscopies, and batteries/sensors/cameras/switches in cars
PCBONLINE's PCB Assembly Capabilities

PCB assembly standard

IPC-A-610 Class 2/3

PCB assembly quantity

From 1 to 100,000+

Finest pitch


Maximum board size

1200mm * 370mm

Minimum panel size

50mm * 50mm

Maximum rectangular part size

50mm * 150mm

Maximum square part size

74mm * 74mm

Maximum component height


PCB thickness

0.08mm to 4mm

Minimum SMD footprint

01005 (0.4mm * 0.2mm)

PCB assembly services

electronic component sourcing
conformal coating
IC programming
functional jig test (free for bulky production)
burn-in test

Free support/services

Gerber and BOM check and improvement
complete PCBA sample (free for bulky production)
first article test
seeking alternative components

On-line PCBA tests

X-ray for ball grid arrays (BGA)
visual inspection

Advantages of the One-Stop PCB Assembly Manufacturer PCBONLINE

manufacturing icon
Our PCBA factory is well-equipped for SMT assembly, THT assembly, testing, and value-added EMS services
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0.05mm fine-pitch, µBGA, and flip-chip PCB assembly capabilities
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Mid and high-end PCBA manufacturing for medical, aerospace, defense, automotive, industrial, and high-performance consumer electronics
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Provide one-on-one engineering support, free DFM, DFT, DFX, and first article test to make sure the high quality of your PCBAs
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Besides PCB assembly, we also provide component sourcing, IC programming, conformal coating, functional testing, and box-built
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For small-batch urgent and complex PCBA orders, we can get into two-shift work to deliver goods in time

PCB Assembly Certifications

ISO certified
IPC certified
IATF certified
RoHS certified
REACH certified
UL certified

We are solution experts to PCB Assembly projects
Contact our team here

best PCB assembly company

PCB assembly Example 1

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"This is an industrial control mainboard PCBA project manufactured by PCBONLINE. Our business department and the production department cooperated vigorously to ensure the quality and delivery time of this batch of motherboards. Our customer praised our soldering level of 01005 surface-mount devices and expressed satisfaction with the cooperation in his email to us."

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