Introduction to EMS PCBs

Printed circuit boards (PCBs) are essential components of most modern electronic devices. PCBs provide the physical structure and electrical connections between the various components that make up an electronic system. As products become more complex, PCB design and manufacturing have become highly specialized skills. This has led many companies to outsource PCB production to external suppliers known as electronics manufacturing services (EMS).

EMS providers offer end-to-end PCB design, fabrication, assembly, and testing services catered to the unique requirements of each customer. Working with an EMS can help companies accelerate time-to-market for new products while reducing costs and manufacturing risks. This guide provides an in-depth look at EMS PCB solutions and how they benefit electronic product development.

Overview of the EMS PCB Process

The EMS PCB production process involves several key steps:

PCB Design

The PCB design process defines the layout of copper traces, component footprints, vias, and other features that will be fabricated on the board. EMS providers offer PCB design services covering:

  • Schematic capture
  • Board layout
  • Signal integrity analysis
  • DFM analysis to optimize manufacturability

Customers can provide initial design requirements and work closely with the EMS designer or submit a completed design for fabrication.

Prototype Production

Once the PCB design is finalized, the EMS will build prototypes for design verification and testing. Prototyping often involves producing small batches of boards with various layer counts and fabrication tolerances.

Volume PCB Fabrication

This involves producing production quantities of the PCB, from tens to thousands of boards. The EMS has fabrication facilities with advanced manufacturing capabilities tailored to high-volume PCB production.

PCB Assembly

The EMS will then assemble the components and devices onto the fabricated PCBs. This includes automated SMT assembly and manual insertion of through-hole parts.

Testing and Quality Control

PCBs from the EMS undergo electrical testing, optical inspection, and quality audits throughout the assembly process. This helps ensure each completed board meets the product’s quality and reliability requirements.

Logistics and Fulfillment

As a final step, the EMS can provide global order fulfillment solutions to deliver customized PCB assemblies wherever and whenever the customer needs them.

Key Benefits of Using an EMS for PCBs

EMS providers offer many advantages over relying on in-house PCB production:

Reduced Time-to-Market

EMS suppliers have the engineering resources and manufacturing capacity to accelerate PCB fabrication and assembly. This allows customers to launch products faster.

Flexible Production Scalability

Customers can start with low-volume prototyping and seamlessly scale up to high-volume production as needed. The EMS manages production capacity behind the scenes.

Cost Savings

Economies of scale allow an EMS to produce PCBs at a lower unit cost compared to a smaller in-house operation. Outsourcing also converts fixed PCB production costs into a variable cost model.

Improved Quality

Experience producing millions of PCBs results in robust quality control and process optimization that is difficult to match in-house. Customers benefit from extremely low defect rates.

Risk Reduction

Relying on an expert EMS reduces technical risks across PCB design, fabrication, and assembly processes. The EMS also handles supply chain complexities related to sourcing components.

Focus on Core Competencies

Outsourcing PCB production to an EMS allows customers to focus their internal engineering and manufacturing resources on core product development strengths.

Factors to Consider When Selecting an EMS Provider

Choosing the right EMS involves evaluating several aspects of their capabilities and approach:

Geographic Location

  • Proximity to the customer’s facilities for shorter product development cycles and supply chain response times. Global geographic coverage also supports international customers and regional production needs.

Engineering and Design Experience

  • Expertise with various PCB technologies, component packages, high-speed signaling, DFM, testability, etc. The ability to support innovative and challenging customer design requirements.

Manufacturing Capabilities

  • Range of available PCB fabrication processes such as layer count, line width/spacing, materials, and special treatments. Support for high-mix and quick-turn requirements.

Assembly Options

  • SMT, thru-hole, advanced packaging, automation, and other assembly technologies. Ability to work with various component types and packages.

Quality Systems

  • Quality control procedures, testing capabilities, process controls and optimization, management standards. Consistent process capability and extremely low defect rates.

Customer Service

  • Responsiveness to requests, design support, supply chain transparency, documentation, ease of doing business. Strong customer focus.

Cost Structure

  • Competitive pricing, minimum order quantities, low prototyping costs, and inventory management programs. Flexibility to meet unique customer cost requirements.

Comparison of Small vs. Large EMS Providers

There is a wide range of EMS companies to choose from. Here is an overview comparing large global EMS companies versus smaller regional providers:

EMS Company SizeSmallLarge
Geographic PresenceLocal/RegionalGlobal
Revenue and Capacity<$100M revenue<br>1-2 facilities>$1B revenue<br>10+ facilities worldwide
Manufacturing TechnologyMainstreamAdvanced
Engineering CapabilitiesBasic design supportHundreds of engineers, extensive expertise
Cost StructurePotentially higher piece costLower piece cost at high volumes
Quality SystemsGoodRobust, optimized over decades
Customer TypeStartups, small/medium companiesLarge enterprises
ResponsivenessVery fastMedium, some bureaucracy

Trends Shaping the EMS Market

Several factors are influencing the continued growth and evolution of EMS solutions for PCB production:

  • Miniaturization – Devices become smaller and use advanced packaging. EMS must support ultra-fine line width PCBs.
  • Industry 4.0 – Data-driven smart manufacturing. EMS implements automation, IoT sensors, analytics, and digital twin technology.
  • Supply Chain Management – Geopolitical factors make supply chains more complex. EMS leverages global sourcing networks.
  • Sustainability – Organizations demand greener production. EMS aims for carbon neutrality and environmental responsibility.
  • Customization – Customers need low-volume, high-mix production. EMS can economically address small to mid-size production runs.

These trends will drive ongoing innovation as EMS providers deliver next-generation PCB solutions tailored to emerging customer needs.


EMS partners provide invaluable PCB design, fabrication, assembly, and testing capabilities that enable companies to successfully develop and manufacture advanced electronic products. Selecting an EMS involves weighing factors such as technical expertise, manufacturing capacity, quality, cost, and customer service. Both large and small EMS providers have unique advantages depending on a customer’s specific requirements and constraints. Continued evolution of the EMS industry will open up new possibilities to accelerate innovation as electronics become ever more essential across countless industries.

Frequently Asked Questions

What are the key differences when comparing PCB manufacturers vs EMS providers?

PCB manufacturers focus exclusively on fabrication of bare printed circuit boards. They provide engineering support for PCB layout/design and optimize their factories for high-volume PCB production. EMS providers offer end-to-end services spanning initial design through testing completed PCB assemblies. This includes sourcing components, SMT assembly, post-assembly testing, and global order fulfillment.

How can EMS improve PCB quality and reliability?

EMS providers accumulate vast experience across thousands of PCB fabrication and assembly projects. They implement rigorous quality systems and leverage Six Sigma, 5S, and other process optimization methods. Stringent testing and inspection regimes improve reliability. These best practices are challenging to match with limited in-house production.

Does outsourcing PCB production result in IP risks?

Reputable EMS providers implement strong IP protection standards within their design, production, and order fulfillment operations. Customers own their PCB data. Manufacturing agreements can include non-disclosure clauses and other IP protections.

Can EMS scale to very high production volumes?

The largest EMS companies have dozens of factories worldwide and can produce millions of PCB assemblies per month. They also have established supply chain networks to procure components at massive scale. EMS provides the production capacity and logistics infrastructure to scale to extremely high PCB volumes.

How does EMS pricing compare to in-house PCB production?

EMS leverages economies of scale and optimized processes to achieve very competitive PCB fabrication and assembly costs, especially at mid to high volumes. Lower capital costs, less waste, and shared overhead vs. in-house production also provide cost advantages. The EMS “pay-as-you-go” model converts high fixed costs into a variable cost structure.

Categories: PCBA


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