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What is EMS Manufacturing and How Does the EMS Mode Work

EMS manufacturing
pcbonline PCBONLINE Team Tues, Jan 10, 2023

EMS manufacturers are electronics contract manufacturers who manufacture and assemble modules or electrical products for original equipment manufacturers (OEMs).

Their EMS manufacturing services enable startups, medium-sized companies, research institutes, and multinational giants to have new products manufactured and bring them to market in the fastest and most affordable way.

OEMs of any size from all industries, such as industrial, automotive, communications, computer, and consumer electronics, can take advantage of the EMS manufacturing mode.

Part 1: What is the EMS Manufacturing Mode

EMS stands for electronic manufacturing service. EMS manufacturing, starting in the 1960s, is also known as electronic contract manufacturing. Nowadays, most electronic products are manufactured from the EMS manufacturing mode.

EMS manufacturing

In an EMS mode, the electronic contract manufacturers provide electronic manufacturing, including components, PCB fabrication, PCB assembly, testings, PCBA value-added until the end products, and box-build assembly. The clients are the OEMs (original equipment manufacturers), research institutes, or business makers that provide the design and own the intellectual property.

Pros of EMS Manufacturing

EMS manufacturing factories are mainly located in Mainland China, Taiwan, Malaysia, Vietnam, and Indonesia. Their customers, which are OEMs, research institutes, business makers, and large end customers are from Europe, America, and other regions. Relying on regional labor cost differences and convenient international transportation, both the EMS manufacturers and their customers benefit from EMS manufacturing.

If you are one of the OEMs, research institutes, business makers, or large end customers, the benefits of EMS manufacturing are:

  • You can hand over the production process to others without investment in electronic manufacturing lines.
  • You can save lots of fabrication costs with regional price differences of production factors, such as labor costs, plant land prices, water and electricity prices, etc.
  • You can focus on R&D and marketing, and you can quickly launch new products to the market with the EMS mode.

Cons of EMS Manufacturing

EMS manufacturers are third-party manufacturers after all, and you may have to face up with these drawbacks:

  • You may be uncertain about the product quality and have to test them after the delivery.
  • Increasing international freight costs in recent years. For products in small quantities, the cargo fee takes a considerable portion of the project cost.
  • Choosing a reliable EMS manufacturer with quality component supply chains takes time, investigation efforts, and trial costs.

To avoid the above possible issues in EMS manufacturing, you can work with a reliable EMS manufacturer PCBONLINE.

Part 2: EMS Manufacturing for OEMs

OEMs are original equipment manufacturers, such as Apple, Dell, Tesla, Autel, small and medium-sized R&D and brand owners companies, etc. They research and develop electrical products and sell these products.

The OEM finishes product development (R&D), including hardware/printed circuit board (PCB) design, software development, and enclosure design.

To have the electronic products manufactured, the OEM sends the Gerber (PCB design graphic files), BOM(bill of materials), requirements, etc, to the EMS manufacturer.


Ensuring the project is feasible by design for manufacturing (DFM), the EMS manufacturer completes PCB fabrication, component sourcing, PCB assembly, testing, value-added services, and box-build assembly services.

Usually, the project fabrication begins with prototypes to bulk production. If the PCB/PCBA/box builds have any issues in use due to the EMS' mistakes, the EMS manufacturer also takes responsibility for repairs and rework. After quality confirmation, the EMS manufacturer delivers the products to the OEM.

Note: EMS manufacturers don't fabricate electronic components but source them. Sometimes, for intellectual property security, OEMs ship confidential components to the EMS manufacturers for PCB assembly rather than letting them source. If the OEM has PCB assembly lines, they only order PCBs and assemble the products on their own.

Many EMS manufacturers such as PCBONLINE are more than hardware manufacturers. With years of experience in fabrication and solving technical issues, they have strong capabilities in hardware and software R&D and can take part in the product design stage with the OEM.


For small-scale OEMs, the involvement of the EMS manufacturer in field application engineering (FAE) can avoid tricky issues after PCB assembly, such as testing failures and software/hardware adjustments.

Multinational giants OEMs like Apple usually divide a product into different modules and assign them to different EMS manufacturers for absolute intellectual property security. OEMs who manufacture small electrical products, such as false eyelash UV disinfection boxes, Bluetooth earphones, electronic door locks, and so on, entrust the whole product to one EMS manufacturer for production.

If you need EMS manufacturing without a quantity limit with one-on-one engineering support, please send your inquiry to info@pcbonline.com.

electronic door lock PCB camera assembly

In the prototype stage, after the first article testing and filed application simulation test, the EMS manufacturer sends the sample to the end customer to try. After the customer's confirmation and approval, the EMS manufacturer finishes bulky production.

For OEMs, EMS manufacturing provides flexible production, high efficiency, and cost-effectiveness. OEMs can select the most suitable EMS manufacturer from their supplier list. They can hire different EMS manufacturers to fabricate different products and not worry about production line capacity when upgrading products.

Part 3: EMS Manufacturing for Research Institutes

Research institutes are at the forefront of high-tech research. Many ideas come into reality by EMS manufacturing for them.

For instance, an agricultural research institute develops LED grow lights with a specific wavelength range and a design suitable for dragon fruit farms, a high-frequency education institute designs Rogers PCBs for cutting-edge HF applications, a biotechnology research institute figures out transparent flexible electrical trays for cell growing and observation, etc.

custom LED EMS manufacturing

Research institutes provide product design, Gerber, BOM, etc, and they need to fabricate their designs and test them through EMS manufacturing from the contract manufacturers.

In such cases, EMS manufacturers can fabricate the whole project, including PCB fabrication, PCB assembly, testing, and box-build assembly.

EMS manufacturing provides the best customization to satisfy research institutes' demands that ready-made products in the market can't. In regards to the EMS manufacturing price, it is affordable. If you want to get a quote for an EMS project, please send your inquiry to info@pcbonline.com.

Part 4: EMS Manufacturing for Business Makers

Besides, EMS manufacturing also serves business makers. However, large-scale EMS manufacturers only work for OEMs whose orders bring them long-term, stable, and bulk profits.

business maker EMS for smart traffic PCBA

For business makers who order low-volume electronic manufacturing, EMS manufacturers such as PCBONLINE meet their demands.

PCBONLINE is a middle-scale EMS manufacturer without a minimum quantity limit to orders. It has more than 20 years of experience in advanced PCB fabrication, and its EMS factory in Shenzhen has more than 10 years of experience in EMS manufacturing. Its EMS manufacturing is traceable and high-quality.

For low-volume PCB fabrication and assembly, PCBONLINE provides quick-turn EMS manufacturing, and the fastest lead time is 12 working hours. The average lead time of EMS manufacturing for business makers is 3 working days.

With EMS manufacturing, research institutes, and business makers can focus on project design and development. However, it may take some time to find a reliable EMS manufacturer, as large-scale EMS manufacturers don't work for small orders, while many smaller EMS manufacturers don't have the capabilities to meet the demands of research institutes and business makers.

Part 5: Service Range of EMS Manufacturing

EMS manufacturing covers everything in fabricating a bare printed circuit board, electrical module (PCBA), electronic system, or an end product labeled and packaged. It is flexible production, meaning you can ask the EMS manufacturer to do anything at any time you want (but it should be feasible for the EMS manufacturer).

The items of EMS manufacturing can be:

Hardware and software design

PCB design

Hardware and software design should consider the fabrication cost, signal integrity, power supply, safety, EMC/EMI, power consumption, thermal dissipation, noise, components, reliability, and design for manufacturing/testing/excellence. Nowadays, chip manufacturers are more and more considerate, and they provide almost all materials such as IC packages, simulation models, PCB designs for reference, etc. You can do the hardware and software design referring to these materials, and the EMS manufacturer can help do that

PCB fabrication and component sourcing

PCB fabrication

After DFM confirmation, the EMS manufacturer fabricates the PCB prototypes first. After quality confirmation from both sides, the EMS manufacturer does the batch PCB fabrication. SMT stencils used for solder paste printing in PCB assembly are also fabricated by the EMS manufacturer.

Meanwhile, the EMS manufacturer sources all electronic components for PCB assembly. The EMS manufacturer PCBONLINE sources components only from original factories and reliable suppliers that have been audited and keep long-term and stable cooperation with. For ICs, PCBONLINE always carries out the counterfeit test. (No worries about the testing fee, it is free.)

PCB assembly

With PCBs and all electronic components, the EMS manufacturer assembles the circuit boards with components. Components include surface-mount devices (SMDs) and THT components. SMDs are soldered on an SMT line, which is automatic. PTH components are soldered on a PTH line, which is half-automatic.

PCB assembly

SMT assembly includes solder paste printing, solder paste inspection, picking and placing SMDs on PCBs, X-ray inspection for BGA, reflow soldering, and AOI inspection.

PTH assembly includes inserting THT component pins through holes, preheating, wave soldering, and trimming pins.

The EMS manufacturer first manufactures five pieces of PCBA and randomly picks up one for the first article test (FAI). All component values are recorded in the FAI report. And the EMS manufacturer sends the report for you to view and confirm. With your approval for batch PCB assembly, the EMS manufacturer completes PCBA production.

Value-added services after PCB assembly

From the EMS manufacturer PCBONLINE, you can avail of value-added services on the PCBA in the post-assembly stage, such as functional testing, conformal coating, thermal aging, IC programming, etc.

PCBA conformal coating

Box-build assembly and delivery

Box-build assembly means installing the mechanical enclosure to the PCBA or the system. The EMS manufacturer assigns the enclosure design to a local partner factory to manufacture samples first and assemble them to be end-product samples.

If you are satisfied with the samples, the EMS manufacturer finally completes the batch box-build assembly and delivers the products to you.

Repair and rework

Believe it or not, the EMS manufacturer is the last person to want any issues or defects during the EMS project or after the product is put in use. Because the whole EMS process is traceable, it is easy to identify who is responsible and how to debug the issue. If the issue is caused by the EMS manufacturer, the EMS manufacturer bears the responsibility for repair or rework.

EMS Manufacturer for Middle and High-End Applications

If you are one of the OEMs, business makers, and research institutes, you can work with PCBONLINE, an EMS manufacturer without a quantity limit to orders.

PCBONLINE has more than 10 years of experience in electronic manufacturing for automotive, medical, industrial, defense, computer, communications, and consumer electronics.

EMS manufacturer

Details of EMS manufacturing from PCBONLINE:

After PCB assembly, PCBONLINE does functional testing and thermal aging. After box build assembly, PCBONLINE conducts field application simulation testing to ensure quality.

PCBONLINE conducts full quality inspection after EMS manufacturing and randomly picks up 10% for quality confirmation.

PCBONLINE has cooperation with FedEx, and sea shipping is cost-effective. If you have an account with the shipping company (FedEx, DHL, or UPS), you can pay the shipping fee using your account.

Relying on the EMS production factory, PCBONLINE joins co-procurement with other larger EMS for components and can enjoy discounts. All components are from original factories or direct first-class suppliers.

Besides these, PCBONLINE has below advantages in EMS manufacturing:

  • PCBONLINE can take part in the R&D of your project for FAE and reduce the fabrication cost with an optimal PCB design.
  • Has two large advanced PCB manufacturing bases and independently completes the whole PCB fabrication process, including gold plating.
  • Provides any kind of PCBs, such as FR4 PCBs of any Tg, aluminum PCBs, copper base PCBs, ceramic PCBs, Teflon PCBs, flexible PCBs, and rigid-flex PCBs.
  • Lead-free PCB assembly with the finest pitch of 0.05mm. Nitrogen reflow and selective soldering are available.
  • Provides one-on-one engineering support throughout your project and quickly solves technical issues.

EMS manufacturing for samples has the same processes, materials, and quality as batch orders. For bulky EMS manufacturing, PCBONLINE provides a free complete sample and PCBA functional testing. If you have a project in design or plan to manufacture it, welcome to contact PCBONLINE by email at info@pcbonline.com for EMS manufacturing.


EMS manufacturing is a popular working mode for electronic manufacturing thanks to the economic and technological progress in the world. It fully integrates advantages in different regions to reduce electronics fabrication costs and increase efficiency. PCBONLINE is an EMS manufacturer for OEMs, business makers, research institutes, and large end customers. If you are one of them and need EMS services, the cost-effective and quality EMS services from PCBONLINE won't let you down.

© This article is an original work of the PCBONLINE team. Please indicate the author PCBONLINE if you reprint. If the article is reproduced without permission or indicating the author's source, PCBONLINE reserves the right to investigate the infringement.


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