How to shield an aluminium enclosure from EMI — conductive anodising, selective masking, gasket lands and design tips.
Standard anodising is an insulator, which is a problem the moment your enclosure has to pass EMC. The good news is that aluminium is easy to make conductive again — the trick is doing it where it matters and not where it hurts.
Make the joint conductive, not the whole box
You rarely need the entire surface conductive. The seam that leaks is the lid joint and any gasket land, so we specify conductive oxidation there, or selectively mask the anodise so gasket lands stay bare metal. Where the joint sits, we machine a continuous shielding shoulder into the profile itself.
Options we use
- Conductive oxidation on the contact faces only.
- Nickel plating on gasket lands for higher attenuation.
- Heat-set or press-fit conductive inserts instead of painted threads.
- Machined grounding features integrated into the profile.
Design the seam before the die is cut
Shielding is a design question as much as a finish one. Tell us the attenuation you need and where the joints sit, and we propose a combination that still works after assembly — including groove geometry for the gasket and fastener pitch that keeps the land compressed. Our materials FAQ covers the substrate side.
Have a project in mind? Send your drawing and get a DFM review plus tooling quote within one working day.