← Application notes · Latch & spring

Replace a spring-and-latch closure with one magnet

Soft-close, hold shut, and a tuned opening force — from a single programmable magnet instead of a spring, a detent, and a catch.

Polymagnet application engineering · 5 min read

A lid, door, or cover has to pull itself closed, stay shut without rattling, and open with a defined, repeatable force. The conventional stack — a spring, a detent, and a mechanical latch — is parts, noise, wear, and a "feel" you tune by trial and error.

One coded magnet, three behaviors

A Spring-Latch Polymagnet handles all three. The coded face attracts across the last gap to soft-close the cover, then holds it firmly shut. A Spring variant does the opposite where you need it — attracting at a distance but repelling below about a centimeter, giving non-contact springiness or a controlled push-open. Because you're shaping the force curve with the pattern, you tune the feel instead of accepting whatever a steel spring gives you.

What that buys the design

You stop tuning springs and start specifying a force curve.

What to specify

Function familySpring-Latch (hold) and/or Spring (repel)
Engagement gapSet for your wall thickness / travel
PairingMatched pair across the closure
MaterialNdFeB (N50), Ni-Cu-Ni; to 60°C

This is core magnetic latch design and magnetic-spring territory — closures, access panels, battery doors, and soft-close drawers.

See the behavior for yourself

It's hard to believe until it's in your hand. Order a demo kit, design your pattern, or talk to an application engineer about a custom force curve.

Order a demo kit Explore the design tool
Sample application note · an example of automated marketing department output · a WholeTech build. Specs are qualitative where public data is limited; confirm force curves with the manufacturer.