EMI shielding covers

Product Overview

EMI shield cans are board-level metal enclosures designed to reduce unwanted electromagnetic interference between sensitive electronic circuits and the surrounding environment. They are commonly installed directly over selected components or functional areas of a printed circuit board, creating a conductive barrier around RF circuits, wireless communication modules, processors, power-management circuits and other interference-sensitive components.

A PCB shielding can does more than simply cover an electronic component. Its shielding performance depends on the complete relationship between the metal enclosure, PCB ground structure, contact points, openings, component height, installation method and operating frequency. For this reason, a properly designed PCB shield can should be considered part of the overall PCB electromagnetic compatibility strategy rather than an isolated sheet-metal component.

Modern electronic products contain increasingly dense PCB layouts, higher processor speeds, faster wireless communication and more compact packaging. These developments increase the possibility of electromagnetic coupling between neighboring circuits. Customized PCB shielding cans and PCB shield cans provide a practical method for separating sensitive circuitry from potential interference sources while occupying relatively little board space.

BaoCheng New Materials manufactures customized metal shielding components according to customer drawings, samples and PCB assembly requirements. Dimensions, material thickness, wall height, openings, mounting features and contact structures can be developed around the actual electronics application.

Why EMI Shield Cans Are Important in Modern Electronics

Electronic circuits continuously generate and receive electromagnetic energy. In a simple circuit board with relatively low operating frequencies, interference between different sections may be limited. In a modern smartphone, communication device or high-density control board, however, RF modules, digital processors, memory, antennas, switching power supplies and high-speed signal lines may operate within only a few millimeters of each other.

This creates two fundamental electromagnetic compatibility problems. The first is emissions: one circuit generates unwanted electromagnetic energy that affects nearby circuitry or leaves the device. The second is susceptibility: a sensitive circuit receives electromagnetic energy generated by another source.

EMI shield cans can help control both problems by creating a conductive enclosure around selected areas of the PCB. When correctly grounded, the shielding structure provides a controlled boundary that reduces electromagnetic coupling between the protected circuit and surrounding components.

However, the effectiveness of a PCB shielding can is determined by much more than material alone. Contact continuity, enclosure geometry, gaps, apertures, seams and PCB grounding all influence the final shielding result.

Board-Level EMI Shielding Applications

Board-level shielding is one of the most common applications for PCB shielding cans. Rather than enclosing the entire electronic device inside a large metal enclosure, engineers can isolate only the circuits that generate significant electromagnetic noise or require additional protection.

This approach is especially useful in compact electronic products because different circuits may have very different EMI requirements. A single PCB may contain RF transceivers, digital processors, analog sensors, power-management circuits and antenna structures. Installing individual PCB shield cans over critical areas allows shielding to be targeted precisely where it is needed.

Typical board-level applications include:

• RF transceiver sections
• Wireless communication modules
• High-speed processors
• Memory and digital processing areas
• Power-management circuits
• Clock-generating circuits
• GPS and GNSS receiver circuits
• Sensor-processing electronics
• Communication interfaces
• Noise-sensitive analog circuits

Because each circuit has different component heights, heat-generation characteristics and frequency ranges, a customized PCB shield can is normally designed according to the actual PCB layout rather than selected only from external length and width.

RF Circuit and Wireless Communication Shielding

RF circuits are among the most common applications for EMI shield cans. Smartphones, wireless routers, IoT devices, communication terminals and other connected electronics may contain several radios operating simultaneously.

Wi-Fi, Bluetooth, cellular communication, GNSS and other wireless systems may be located on the same PCB or within the same compact device. Without appropriate electromagnetic control, signals generated by one circuit can couple into another circuit and affect receiver sensitivity, signal integrity or system performance.

A PCB shielding can positioned over an RF section helps create physical and electromagnetic separation between the protected circuitry and neighboring modules. The design must still allow connections, PCB traces and other required interfaces to pass through or beneath the shield.

For this reason, the dimensions and openings of PCB shielding cans should be determined together with the RF layout. A shield that simply covers the components but creates excessive gaps or poorly controlled apertures may provide significantly less shielding than expected.

Smartphone and Mobile Device Applications

Smartphones are one of the most demanding environments for board-level shielding. A modern smartphone combines cellular RF systems, Wi-Fi, Bluetooth, GNSS, NFC, processors, memory, cameras, display electronics, charging circuits and power-management components within an extremely limited internal space.

Multiple EMI shield cans may therefore be installed across different PCB areas inside the same mobile device. Each enclosure can protect a specific circuit group while allowing the overall smartphone architecture to remain compact.

A smartphone PCB shielding can may be used around RF front-end components, transceiver circuits, processors, memory modules or selected power-management components depending on the device architecture.

Because smartphone internal space is extremely limited, the height of the PCB shield can is particularly important. Excessive shield height can interfere with batteries, displays, camera assemblies, housings or other internal structures. Insufficient height, on the other hand, can create component interference during assembly.

For mobile electronics, customized PCB shield cans therefore require careful control of length, width, height, wall position, local clearances and manufacturing flatness.

Processor and High-Speed Digital Circuit Applications

Modern processors and digital circuits switch at very high speeds. Even when a digital device does not intentionally transmit radio-frequency signals, rapid switching edges can generate high-frequency electromagnetic energy.

This noise can couple into nearby analog, RF or sensor circuits. Depending on the electronics architecture, PCB shielding cans may be used around selected processing sections to reduce interaction with neighboring circuitry.

A PCB shield can used for processor-related applications must also consider thermal management. A metal shield should not automatically be treated as a heat sink. The thermal behavior depends on material, shield geometry, internal airflow, thermal interface design and the relationship between the enclosure and other heat-spreading structures.

Where processors or other components generate significant heat, shielding and thermal requirements should therefore be evaluated together rather than independently.

Power Management and Switching Circuit Applications

Switching regulators, DC-DC converters and other power-management circuits can generate electromagnetic noise because they repeatedly switch electrical current at relatively high frequencies.

In densely packed electronics, noise from these circuits can affect RF receivers, audio circuits, sensors or other sensitive components. A properly designed PCB shielding can can help isolate selected power-management sections from nearby circuitry.

The shielding design must still account for heat, current paths, component height and PCB routing. If ventilation openings are required, their number, dimensions and positions should be carefully considered because apertures can influence shielding performance.

Customized PCB shield cans make it possible to balance electromagnetic protection, space limitations and thermal requirements for a specific board design.

IoT and Wireless Device Applications

Internet of Things devices often combine wireless communication, sensing, data processing and power-management functions on a very small circuit board. This creates another common application for EMI shield cans.

Smart sensors, wireless modules, gateways, tracking devices, wearable electronics and connected industrial equipment may contain RF circuits positioned close to microcontrollers or switching power supplies.

A customized PCB shield can can isolate these functional areas while maintaining the compact dimensions required by the final device.

Because many IoT products are highly space-constrained, designers should evaluate the shield early in the PCB development process. Adding PCB shielding cans only after the PCB layout has been completed may create problems with available board space, component clearance or grounding locations.

Automotive Electronics Applications

Modern vehicles contain a rapidly increasing number of electronic control systems, communication modules, sensors and power electronics. These systems operate in an electromagnetic environment that may include motors, switching power supplies, communication systems and high-current electrical circuits.

Depending on the design, PCB shielding cans may be used inside automotive control modules, communication electronics, infotainment systems, sensor modules and other compact electronic assemblies.

Automotive applications normally require careful consideration of vibration, temperature variation, corrosion environment and long-term mechanical stability in addition to electromagnetic shielding.

A PCB shielding can intended for automotive electronics should therefore be evaluated not only for its nominal dimensions but also for how consistently it maintains contact with the PCB or supporting frame throughout the product's operating conditions.

Industrial Control and Automation Applications

Industrial electronics often operate close to motors, relays, inverters, switching equipment and other potential interference sources. At the same time, industrial control boards may contain sensitive microcontrollers, communication circuits and analog measurement electronics.

EMI shield cans can be used to provide localized shielding around selected circuits without requiring the entire PCB to be placed inside separate internal metal enclosures.

Applications may include industrial controllers, communication modules, sensor interfaces, automation equipment and precision measurement electronics.

For these applications, the PCB shield can geometry can be customized around component groups while maintaining access to connectors, test points or other functional areas when required.

Medical and Precision Electronic Equipment

Some medical and precision electronic devices contain low-level signals, sensitive sensors or wireless communication circuits that may require careful electromagnetic compatibility design.

A PCB shielding can may be used as one element of the overall EMC strategy to reduce electromagnetic interaction between selected functional sections.

The actual shielding requirement depends on the complete device architecture and regulatory requirements. Therefore, PCB shield cans should not be treated as a substitute for proper circuit design, filtering, grounding and EMC testing. Instead, they work together with these measures as part of the complete electromagnetic control system.

One-Piece and Two-Piece PCB Shielding Structures

Different electronic assemblies may use different shielding structures. One common design is a one-piece PCB shield can that is directly attached to the PCB. This structure is relatively simple and can provide a compact enclosure around the protected circuit.

Another common structure uses a separate shielding frame and removable cover. The frame is installed on the PCB while the top cover can be removed during inspection, testing or repair.

Two-piece PCB shielding cans are particularly useful when manufacturers require access to components after the shielding frame has been attached.

The correct structure depends on production method, service requirements, PCB layout and available installation space. BaoCheng can manufacture customized shielding components according to the customer's selected structure and drawing.

Importance of Grounding and Electrical Contact

A metal enclosure alone does not guarantee effective electromagnetic shielding. One of the most important factors affecting EMI shield cans is the quality of the electrical connection between the shield and the PCB ground system.

When the PCB shielding can is connected to appropriate PCB grounding locations, electromagnetic currents can be directed through the conductive structure. Poor contact, excessive gaps or inconsistent contact pressure can reduce shielding effectiveness.

The contact structure may include soldered edges, mounting tabs, frame contacts or other features depending on the design.

For this reason, the lower edge geometry of a PCB shield can is a functional feature rather than simply a dimensional boundary. Contact surfaces, tab locations and local flatness should be controlled according to the PCB mounting design.

Openings and Aperture Design

A completely closed metal enclosure generally provides a more continuous conductive barrier, but practical PCB shield cans may require openings for cooling, connectors, cables, test points or manufacturing access.

These openings can affect shielding performance because electromagnetic energy may couple through apertures.

The influence of an opening depends on several factors, including:

• Opening size
• Opening shape
• Number of openings
• Operating frequency
• Position relative to interference sources
• Position relative to sensitive circuits

This means that ventilation holes or access windows in a PCB shielding can should not be added only for visual or manufacturing reasons. Their location should be considered as part of the electromagnetic design.

Shield Height and Component Clearance

The internal height of a PCB shield can must provide sufficient clearance above the electronic components located underneath it.

Component height tolerance, solder thickness, PCB deformation and manufacturing variation should all be considered. If the internal clearance is too small, components may contact the shield during assembly or use.

At the same time, increasing the height of PCB shield cans unnecessarily can increase occupied volume and interfere with surrounding structures.

This is especially important in smartphones, wearables and other ultra-thin electronics where fractions of a millimeter can influence the complete mechanical stack.

Wall Geometry and PCB Layout

The perimeter of a PCB shielding can is normally designed around a specific circuit area. Straight walls may be sufficient for simple layouts, while complex PCBs may require stepped edges, cutouts, irregular profiles or local clearances.

The shield outline should avoid interference with neighboring components while maintaining sufficient room for grounding or solder attachment.

A customized PCB shield can can therefore follow the actual component layout more closely than a generic rectangular shield.

When designing the enclosure, engineers should also consider whether the shield geometry is suitable for stamping and forming. Extremely narrow walls, small corner radii or closely positioned features may increase tooling and manufacturing difficulty.

Material Considerations for EMI Shield Cans

Material selection affects mechanical strength, formability, corrosion resistance, conductivity, magnetic behavior and surface-treatment compatibility.

For precision stamped shielding components, stainless steel can provide useful mechanical strength, corrosion resistance and dimensional stability. BaoCheng can evaluate stainless-steel shielding structures according to the customer's drawing, thickness and forming requirements.

For projects where magnetic behavior is particularly important, special low-magnetic-permeability material requirements can also be discussed according to the application.

It is important to understand that the material of EMI shield cans is only one factor affecting actual EMI performance. Conductive continuity, grounding, seam structure and apertures can be equally important.

Thickness Selection for PCB Shielding Cans

Material thickness influences both mechanical performance and manufacturability. A thicker PCB shielding can may provide greater rigidity, but it also increases weight, material usage and forming force.

A thinner PCB shield can can reduce occupied space and weight but may be more sensitive to deformation during stamping, handling and assembly.

The appropriate thickness should therefore be selected according to:

• Shield dimensions
• Wall height
• Material properties
• Required rigidity
• Assembly method
• Available internal space
• Stamping geometry

There is no single material thickness that is suitable for all PCB shielding cans. The complete enclosure geometry should be evaluated before confirming the specification.

Stamping Accuracy and Dimensional Control

Because EMI shield cans are often used in compact PCB assemblies, dimensional control is important for reliable installation.

Critical dimensions may include:

• Overall length and width
• Shield height
• Wall position
• Mounting tab position
• Opening dimensions
• Opening position
• Corner geometry
• Bottom-edge flatness
• Cover-to-frame fit for two-piece structures

For a customized PCB shielding can, these dimensions should be controlled according to their actual function rather than applying unnecessarily tight tolerances to every feature.

Dimensions affecting PCB alignment, contact, cover fit and surrounding-component clearance normally deserve the highest level of attention.

Flatness and Coplanarity Requirements

The bottom edge of a PCB shield can may interface directly with PCB grounding pads, solder locations or a separate shielding frame. Excessive deformation can create uneven contact or assembly difficulties.

Thin stamped structures can distort because of material stress, punching, forming sequence or handling. Tooling and process development should therefore consider flatness and coplanarity from the beginning.

For larger or more complex PCB shield cans, local deformation can become especially important because dimensional error at one area may affect contact conditions elsewhere around the perimeter.

Burr and Edge Control

Burr control is another important consideration for precision PCB shielding cans. The shielding component may be installed close to electronic components, flexible circuits, batteries or other delicate structures.

Uncontrolled sharp edges can create handling and assembly risks. Burr direction can also influence how the part contacts the PCB or fits into surrounding structures.

Punching direction, trimming method and critical contact surfaces should therefore be considered during development of the PCB shield can.

Surface Treatment and Contact Areas

Surface condition can influence corrosion resistance, solderability, contact performance and appearance depending on the shielding design.

If the PCB shielding can requires specific conductive or solderable contact areas, these requirements should be identified on the drawing.

Not every surface necessarily performs the same function. Some areas may require reliable electrical contact, while others are mainly structural surfaces. Understanding these functional differences helps determine appropriate manufacturing and finishing requirements.

Design for Automated PCB Assembly

For high-volume electronic manufacturing, PCB shielding cans may need to be compatible with automated placement and soldering processes.

Part geometry, orientation, pickup surface and dimensional consistency can influence automated assembly reliability.

A PCB shield can intended for automated production should therefore be designed not only for shielding performance but also for repeatable handling and placement.

For large-volume projects, packaging and part orientation may also need to be considered because deformation during transportation can affect downstream assembly.

Prototype Development and Validation

Prototype development is useful before mass production of customized EMI shield cans. Early samples allow engineers to evaluate whether the shielding enclosure fits the PCB and surrounding mechanical structure correctly.

Prototype validation may include:

• PCB fit verification
• Component-height clearance
• Mounting-tab alignment
• Grounding contact verification
• Cover retention
• Opening position
• Assembly interference
• Flatness verification

After mechanical fit is confirmed, electromagnetic compatibility testing of the complete electronic assembly can determine whether the PCB shielding can performs as required within the actual device architecture.

Custom PCB Shielding Can Development

Although standard PCB shield cans are available for some general applications, many modern electronic products require customized shielding because PCB layouts vary significantly.

BaoCheng New Materials manufactures customized shielding components according to customer drawings and project requirements.

Useful information for evaluating a custom PCB shielding can project includes:

• 2D drawings
• 3D models
• Material specification
• Material thickness
• Overall shield dimensions
• Internal component height
• Required openings and cutouts
• Mounting or soldering structure
• Critical tolerances
• Flatness requirements
• Surface requirements
• Prototype quantity
• Expected production volume

Providing the PCB layout or relevant surrounding-component information can also help identify possible interference and manufacturability issues during development.

How to Select the Right EMI Shield Can Supplier

When sourcing customized EMI shield cans, buyers should evaluate more than external dimensions and unit price.

The supplier should understand that the component is part of an electronic assembly and that dimensional errors can affect PCB installation, grounding, component clearance and automated production.

A suitable supplier should be able to discuss:

• Material selection
• Stamping feasibility
• Wall and corner geometry
• Critical dimensional tolerances
• Flatness
• Burr control
• Opening design
• Prototype verification
• Mass-production consistency

For a custom PCB shield can, it is also useful to explain which dimensions affect PCB contact, component clearance or cover installation. This allows manufacturing control to focus on the features that have the greatest functional importance.

Why Work With BaoCheng New Materials?

BaoCheng New Materials focuses on customized precision metal components for electronic applications. Our PCB shielding cans are developed according to customer drawings rather than treated as generic consumer replacement products.

For each PCB shielding can project, dimensions, material thickness, wall structure, openings, forming requirements and critical assembly features can be reviewed before production.

This engineering-focused approach is important because shielding components often need to fit into extremely limited spaces while maintaining consistent contact with PCB structures.

Customers developing smartphones, communication devices, IoT electronics, automotive modules, industrial equipment or other electronic products can provide drawings or samples for evaluation and customized PCB shield cans development.

Conclusion

EMI shield cans are important board-level components used to control electromagnetic interaction between circuits in modern electronic products. Their applications include RF modules, smartphones, wireless devices, processors, power-management circuits, automotive electronics, industrial control boards and other high-density electronic systems.

Effective shielding depends on much more than placing a metal cover over a circuit. The performance of a PCB shielding can is influenced by grounding, contact continuity, openings, seams, component clearance, shield geometry and the complete PCB architecture.

At the manufacturing level, dimensional accuracy, height control, flatness, burr condition, wall geometry and material thickness all affect whether a PCB shield can can be assembled reliably.

BaoCheng New Materials provides customized PCB shield cans and other precision stamped electronic components according to customer drawings and project requirements. For new projects, providing the PCB structure, drawings and critical assembly requirements allows manufacturing feasibility to be evaluated before tooling and volume production.

FAQ

What are EMI shield cans used for?

EMI shield cans are conductive metal enclosures installed over selected areas of a PCB to reduce unwanted electromagnetic interaction between electronic circuits. They are commonly used around RF circuits, wireless communication modules, processors, power-management circuits and other sensitive or noise-generating electronics.

What is a PCB shielding can?

A PCB shielding can is a board-level metal enclosure designed to cover a specific electronic circuit area. When integrated with the PCB grounding structure, it can help reduce electromagnetic emissions from the protected area and reduce interference entering sensitive circuitry.

What is the difference between a PCB shield can and a complete device enclosure?

A PCB shield can provides localized shielding around selected PCB components, while a complete device enclosure surrounds a much larger portion of the electronic system. Localized PCB shield cans are especially useful when only certain RF, digital or power circuits require additional electromagnetic isolation.

Do PCB shielding cans completely eliminate EMI?

No. PCB shielding cans are one part of a complete EMC design. Final performance also depends on PCB layout, grounding, filtering, apertures, seams, cable routing, enclosure design and the frequency of the electromagnetic interference. Shielding effectiveness should therefore be verified in the complete electronic assembly.

Does thicker metal always provide better EMI shielding?

Not necessarily. Increasing material thickness may improve mechanical rigidity, but shielding effectiveness is also strongly influenced by electrical conductivity, grounding continuity, gaps, apertures and seams. A well-designed thin PCB shielding can can therefore perform better than a thicker enclosure with poor grounding or large openings.

Why is grounding important for a PCB shield can?

Grounding creates a controlled conductive path between the PCB shield can and the PCB ground system. Poor or inconsistent contact can allow electromagnetic energy to couple through gaps or discontinuities, reducing the effectiveness of the shielding structure.

Can PCB shield cans have ventilation holes?

Yes. PCB shield cans can include ventilation holes, access openings or other cutouts when required by the product design. However, aperture dimensions and positions can influence shielding performance, particularly at higher frequencies, so they should be considered as part of the overall EMC design.

What dimensions are important when designing a PCB shielding can?

Important dimensions normally include overall length, width, height, internal component clearance, wall position, mounting-tab position, opening dimensions and bottom-edge flatness. The most important tolerances for a PCB shielding can are usually those that affect PCB alignment, grounding contact and surrounding-component clearance.

What is the difference between one-piece and two-piece PCB shielding cans?

A one-piece PCB shielding can normally forms a complete enclosure that is installed directly onto the PCB. A two-piece structure typically consists of a soldered or mounted frame plus a removable cover. Two-piece PCB shield cans can provide easier access to components during testing, inspection or repair.

Can EMI shield cans be used in smartphones?

Yes. Smartphones commonly use multiple EMI shield cans because RF, Wi-Fi, Bluetooth, GNSS, processors, memory and power-management circuits are located extremely close to each other. Individual shielding areas help control electromagnetic interaction within the compact internal architecture.

Can a PCB shield can also work as a heat sink?

A PCB shield can may participate in heat spreading in certain designs, but it should not automatically be treated as a dedicated heat sink. Actual thermal performance depends on material, component contact, thermal interfaces, airflow and the complete device thermal-management architecture.

What material can be used for EMI shield cans?

Material should be selected according to shielding requirements, mechanical strength, corrosion resistance, forming characteristics, magnetic requirements and assembly method. Stainless steel can be used for precision stamped EMI shield cans where mechanical strength, corrosion resistance and dimensional stability are important. Special material requirements can be evaluated according to the customer's application.

Can PCB shielding cans be customized according to our PCB layout?

Yes. BaoCheng New Materials develops customized PCB shielding cans according to customer drawings, PCB layouts, samples and technical requirements. Customization can include overall dimensions, wall height, openings, tabs, irregular profiles, material thickness and other structural features.

What files should I provide for a custom PCB shield can quotation?

For a customized PCB shield can, it is recommended to provide 2D drawings or 3D models together with material, thickness, critical tolerances, component-height requirements, mounting structure, surface requirements, prototype quantity and expected production volume. Information about surrounding PCB components can also help with manufacturability evaluation.

Should EMI performance be tested after the PCB shielding can is installed?

Yes. Although dimensional and material characteristics of the PCB shielding can can be controlled during manufacturing, actual shielding effectiveness depends on the complete assembled electronic system. EMC or RF validation after assembly is therefore important for applications with defined electromagnetic performance requirements.