MuCans® MuMetal® Magnetic Shielding Cans
Precision magnetic shielding cans for transformers, inductors and sensitive electronics
MuCans® are compact MuMetal® magnetic shielding cans designed to reduce low-frequency magnetic interference around transformers, inductors, sensors and sensitive electronic components.
Available in circular and rectangular formats, MuCans® can be deep drawn, metal spun or fabricated to suit the size, geometry and quantity required. Standard designs can be modified with lids, holes, cutouts and cable lead-throughs, while fully custom magnetic shielding enclosures can be developed for specialist applications.
What is a MuMetal® shielding can?
A MuMetal® shielding can is a high-permeability magnetic enclosure placed around a component that generates a magnetic field, or around equipment that needs protection from an external field.
The MuMetal® provides a preferred path for magnetic flux, redirecting it through the shielding material and reducing the field passing into or escaping from the enclosed area. This makes MuCans® particularly suitable for controlling static and low-frequency magnetic interference where space is limited.
MuCans® are not general-purpose high-frequency RF shields. Their design is focused on magnetic-field attenuation, with the required material, thickness, geometry, openings and annealing process selected for the application.
Typical Applications
MuMetal® magnetic shielding cans are commonly used for:
Power and audio transformers
Inductors, chokes and other wound components
Power supplies and power-conversion electronics
Sensitive magnetic sensors and measurement devices
Medical and laboratory electronics
Aerospace and defense electronics
Test, calibration and instrumentation systems
Board-level magnetic shielding
Containment of magnetic leakage from individual components
Protection of sensitive components from nearby magnetic-field sources
MuCans® Manufacturing Options
Deep-drawn MuMetal® cans
Deep drawing produces a seamless magnetic shielding can with no welded side joint. It is particularly suitable for standard sizes, repeat orders and higher production quantities.
Our deep-drawn MuCans® are available in circular and rectangular forms. The final depth can be trimmed to suit the application, subject to forming limitations associated with the can diameter or base dimensions.
If an existing size is unsuitable, tooling can be developed for a custom deep-drawn can in MuMetal® or another suitable soft magnetic alloy. Handmade prototypes may also be produced to evaluate a new design before committing to production tooling.
Metal-spun MuMetal® cans
Metal spinning provides an alternative method of producing circular MuMetal® cans, particularly for diameters or quantities that are not suited to existing deep-drawing tooling.
Spun cans can be manufactured with matching lids and customer-specified holes or cutouts. A modest tooling requirement may apply, depending on the geometry.
Fabricated MuMetal® cans
Fabricated MuCans® provide greater flexibility for larger sizes, low production quantities and bespoke geometries where conventional deep drawing would be impractical.
Depending on the design, fabricated shielding cans can be manufactured using forming, spot welding or welding. Matching lids, apertures and lead-through arrangements can be incorporated to suit the component and its connections.
Materials and Magnetic Annealing
MuCans® are normally manufactured from high-permeability MuMetal® conforming to ASTM A753 Alloy 4. Typical material thicknesses range from 0.5 mm to 1.0 mm, although the selected thickness depends on the can dimensions, manufacturing method and magnetic-field conditions.
Forming, welding, machining and general handling can reduce the magnetic permeability of MuMetal®. For this reason, MuCans® undergo a controlled hydrogen magnetic anneal after the principal manufacturing operations have been completed. This final heat treatment restores and optimizes the soft magnetic properties of the material.
Completed shield performance still depends on the material thickness, geometry, lid fit, apertures, field strength and orientation. These factors should be considered together rather than selecting a can by material grade alone.
Standard Circular MuCans®
The following circular MuCans® are produced using existing deep-drawing or metal-spinning tooling. Dimensions shown are internal dimensions.
| Can reference | Manufacture | Internal diameter | Maximum internal depth | Nominal thickness |
|---|---|---|---|---|
| RC19.0 | Deep drawn | 19.0 mm / 0.75 in | 19.0 mm / 0.75 in | 0.8 mm / 0.032 in |
| RC24.4 | Deep drawn | 24.4 mm / 0.96 in | 19.3 mm / 0.76 in | 0.8 mm / 0.032 in |
| RC30.2 | Deep drawn | 30.2 mm / 1.19 in | 47.0 mm / 1.85 in | 0.8 mm / 0.032 in |
| RC39.0 | Deep drawn | 39.0 mm / 1.54 in | 52.0 mm / 2.05 in | 0.8 mm / 0.032 in |
| RC33.3 | Metal spun | 33.3 mm / 1.31 in | 27.0 mm / 1.06 in | 0.8 mm / 0.032 in |
| RC48.9 | Metal spun | 48.9 mm / 1.93 in | 39.0 mm / 1.54 in | 0.8 mm / 0.032 in |
| RC59.0 | Metal spun | 59.0 mm / 2.32 in | 65.0 mm / 2.56 in | 0.8 mm / 0.032 in |
| RC88.0 | Metal spun | 88.0 mm / 3.46 in | 44.0 mm / 1.73 in | 0.8 mm / 0.032 in |
Circular cans can be supplied with inside- or outside-fitting lids. The depth shown is the maximum available and can be reduced to suit the application. Holes and cutouts can be added as required.
Standard Rectangular MuCans®
The following rectangular MuCans® are produced using existing deep-drawing tooling. Dimensions shown are internal dimensions.
| Can reference | Internal length | Internal width | Maximum internal depth | Nominal thickness |
|---|---|---|---|---|
| RECT34.6 | 34.6 mm / 1.36 in | 28.2 mm / 1.11 in | 24.2 mm / 0.95 in | 0.5 mm / 0.020 in |
| RECT28.2 | 28.2 mm / 1.11 in | 23.2 mm / 0.91 in | 22.5 mm / 0.88 in | 0.5 mm / 0.020 in |
| RECT22.9 | 22.9 mm / 0.90 in | 17.0 mm / 0.67 in | 17.8 mm / 0.70 in | 1.0 mm / 0.039 in |
Rectangular MuCans® can be supplied with flat lids manufactured to suit the design. The depth shown is the maximum available and can be reduced. Holes and cutouts can also be incorporated.
Standard dimensional tolerance: ±0.25 mm (0.010 in), unless otherwise agreed.
Standard sizes and availability are subject to confirmation at the time of enquiry. Our tooling range continues to develop, so additional sizes may be available.
Lids, Holes and Custom Features
A shielding can rarely be designed independently of the component connections and mounting arrangement.
MuCans® can therefore be configured with:
- Inside- or outside-fitting circular lids
- Flat lids for rectangular cans
- Cable lead-through holes
- Pierced or drilled apertures
- Slots and custom cutouts
- Modified can depths
- Component and mounting clearances
- Customer-specific lid and hole patterns
Openings interrupt the magnetic path and can affect shielding performance. Their size, position and orientation should therefore be considered during the initial design rather than added after annealing.
Standard or Custom Magnetic Shielding Cans
An existing MuCan® is often the most practical starting point. Standard tooling can be used to produce different depths, lid arrangements and hole configurations without creating an entirely new can design.
Where the required dimensions fall outside the existing range, Magnetic Shields can evaluate the most appropriate manufacturing route:
- New tooling for a custom deep-drawn can
- Metal spinning for a circular design
- Fabricated construction for large, low-volume or unusual requirements
- Prototype manufacture before production tooling
The selected route depends on geometry, quantity, dimensional requirements, material thickness and the magnetic shielding objective.
Quality and Inspection
MuCans® are manufactured using controlled forming, fabrication and heat-treatment processes. Dimensional inspection is undertaken against the agreed drawing or standard can specification.
Where specific magnetic performance is required, the field conditions, measurement position and acceptance method should be agreed during the design stage. Magnetic attenuation cannot be represented by one universal value for every can because it depends on the completed geometry and the field in which the shield is used.
Designing an Effective MuMetal® Can
The effectiveness of a magnetic shielding can depends on more than its wall thickness. Important design considerations include:
- Strength and orientation of the magnetic field
- Whether the shield contains a field source or protects a sensitive component
- Required reduction in magnetic field
- Can diameter, length and aspect ratio
- Clearance between the component and shield
- Open end, lid and overlap configuration
- Number, size and location of holes or lead-throughs
- Risk of magnetic saturation
- Mechanical tolerances and assembly method
- Production quantity and preferred manufacturing route
Our technical team can review these factors and recommend a suitable standard or custom configuration.
Information Needed for a MuCan® Quotation
To help us identify the most suitable magnetic shielding can, please provide:
- Component drawing or overall dimensions
- Required internal clearance
- Preferred can shape and maximum external envelope
- Required can depth
- Lid arrangement
- Number, diameter and position of holes or cutouts
- Quantity required
- Available information about the magnetic-field source
- Required field reduction or equipment sensitivity
- Any dimensional, environmental or inspection requirements
Where the magnetic environment is not fully known, send us the available component and application details and our technical team can help determine the next steps.
Frequently Asked Questions
Can you develop a shield if the final specification is not yet known?
Yes. Transformer shielding is one of the most common MuCan® applications. The can surrounds the transformer and redirects magnetic leakage through the high-permeability material, helping to reduce the field reaching nearby components. The required design depends on the transformer field, orientation, size and available clearance.
Can a MuCan® protect a sensitive component from an external magnetic field?
Yes. A MuCan® can be used either to contain magnetic leakage from a component or to reduce the external magnetic field reaching sensitive electronics, sensors or instrumentation.
Are MuCans® available in standard sizes?
Yes. We have standard circular and rectangular MuCans® manufactured using existing deep-drawing and metal-spinning tooling. Depths, lids and hole configurations can be adapted within the limits of the selected design. Availability is confirmed at the time of enquiry.
Can you manufacture a completely custom MuMetal® can?
Yes. Custom cans can be deep drawn using dedicated tooling, metal spun or fabricated. The most appropriate method depends on the required dimensions, geometry and quantity.
Can holes or cable lead-throughs be added?
Yes. Holes, slots and other cutouts can be incorporated before final magnetic annealing. Because openings can affect shielding performance, their size and position should be defined during the design stage.
Why is hydrogen annealing required?
Manufacturing operations introduce mechanical stress into MuMetal® and reduce its magnetic permeability. Hydrogen annealing after forming and fabrication restores and optimizes the material’s soft magnetic properties.
Can a MuCan® be machined or modified after annealing?
Post-annealing machining, drilling, bending or impact can locally reduce the magnetic properties of MuMetal®. Wherever possible, all holes and mechanical features should be completed before the final hydrogen anneal. Any required post-annealing modification should be discussed with Magnetic Shields.
How much magnetic attenuation will a MuCan® provide?
There is no single attenuation value applicable to every MuCan®. Performance depends on the material, thickness, geometry, openings, lid arrangement, field strength, field direction and measurement position. Where a defined reduction is required, these conditions should be reviewed as part of the design.
Request a Custom MuCan® Quotation
Magnetic Shields USA supplies standard and custom MuMetal® magnetic shielding cans for prototypes, specialist equipment and production requirements.
Send us your component drawing, dimensions, quantity and available magnetic-field information. Our technical team will review whether an existing deep-drawn or spun MuCan® can be adapted, or whether a custom fabricated or tooled design is more appropriate.