How Manufacturing Sequence Affects Magnetic Shielding

Annealing is a crucial step in the manufacturing of magnetic shielding and should be the final step whenever possible. Final annealing helps relieve internal stress in the material so the shielding can achieve the permeability needed to block harmful magnetic interference in critical applications. 

But once a component has been annealed, it must be handled carefully. Secondary processing after annealing can alter the material’s magnetic properties and reduce the shielding effectiveness. 

For customers developing custom magnetic shielding, understanding when secondary processing should occur can help prevent manufacturing issues and protect the performance of the finished component. 

Ad-Vance Magnetics Inc. understands how manufacturing processes impact magnetic shielding performance and has processes in place to help customers ensure optimal shielding performance. 

Plan Secondary Processing Before Annealing

Because post-anneal operations can cause a significant loss of permeability, it is important to plan the manufacturing sequence from the beginning. Machining, welding, forming, and hardware installation should be completed before final annealing whenever possible.

A single post-anneal operation, including wet drilling, dry drilling, TIG welding, spot welding, bending, fastener over-torquing, or forced assembly, can result in a 40% to 90% loss in localized magnetic permeability, depending on the stress introduced.

That makes manufacturing sequence an important consideration from the beginning of a project.

Early design for manufacturing collaboration can help determine the right manufacturing sequence for a shielding component. By reviewing CAD files before production, our team can identify features and operations that should be completed before annealing, including holes, cutouts, hardware, brackets, bends, and other assembly requirements. 

Whenever possible, we recommend completing machining, welding, and dimensional inspection before final annealing. 

Once components have been annealed, we recommend handling them with the same care you would use when handling glass throughout final assembly, inspection, packaging, shipping, and installation. 

Account for Dimensional Movement During Annealing

Annealing exposes magnetic shielding materials to temperatures up to 2,050°F, allowing the metal to relax and potentially move. 

It’s important to account for this movement during design and manufacturing. 

For example, an annealed component may shift slightly during the process and no longer align perfectly with another component during final assembly. Understanding this possibility before production allows the manufacturing process to account for dimensional changes without compromising the shielding.

When this occurs, it is important to handle the components with caution and use hand massaging to fit them together. Using mallets, pry bars, or other forceful methods to pull or reshape the material can degrade shielding performance.

Ad-Vance’s Expertise Helps Protect Shielding Performance

Ad-Vance’s expertise helps customers determine the appropriate manufacturing sequence for their shielding components. 

Our team performs secondary machining, tapping, and hardware installation, including PEMs and brackets, before annealing whenever the design allows. Completing these operations beforehand helps minimize mechanical stress introduced after annealing.

However, some applications require hardware to be installed post-anneal because of assembly requirements or tolerances. When post-anneal hardware installation is unavoidable, our team uses specialized fixturing and low-stress processes to minimize loss of permeability.

Ensuring Optimal Permeability

Because post-annealing processing can have detrimental effects on the effectiveness of magnetic shielding, planning the manufacturing sequence early can help reduce risk.

By involving our team early in the process, we can collaborate to identify potential post-anneal challenges, complete as much processing before annealing as possible, and develop an appropriate approach when post-anneal processing is necessary. 

Partner with magnetic shielding experts. Request a quote from Ad-Vance Magnetics today.