Magnets for mechanical engineering
Short answer: in machines you mainly use magnets for removable panels, guards and inspection hatches (quick to open without tools), for fixing sensors, lighting and cables, and for positioning during assembly. Usually you choose pot magnets with a threaded stud, internal thread or countersunk hole, because they can be screwed firmly in place and give a lot of force on thick steel. Watch out for vibrations, heat and oil, and secure panels that must not fall.
Which magnet for which application?
| Application | Advice |
|---|---|
| Removable plate or cover on a steel frame | pot magnet with countersunk hole, 2 – 4 per panel; see magnets for inspection hatches |
| Fixing a bracket, sensor or lamp | pot magnet with threaded stud or internal thread |
| On painted steel, without scratches | rubber pot magnet |
| Routing cables and hoses | rubber pot magnet Ø31 mm with cable mount; see cable management |
| Removing metal particles from liquid or product | filter magnets; see which filter magnet should you choose? |
| Positioning and jigs in production | see magnets for assembly and production |
What to watch out for in a machine?
- Vibrations: vibrations make a panel slide away sooner than you expect. Load magnets perpendicularly as much as possible and allow at least a 3 times margin.
- Temperature: near motors, ovens or hydraulics it can exceed 80 °C. Then choose a higher temperature class (H or SH). See magnets at high temperatures.
- Thin sheet metal: a pot magnet on 1 – 2 mm sheet only reaches part of its holding force. See how is holding force determined?
- Metal chips: magnets attract chips. Place them outside the chip zone or choose a covered version.
- Safety: guards that shield moving parts must not open without tools if the Machinery Directive or the risk assessment does not allow it. A magnet is then no substitute for an interlock.
Frequently asked questions
How many pot magnets do I need for a panel?
At least two, for larger panels four (in the corners). Add up the holding force and divide by 3 to 5 for a safe practical value with vertical panels.
Can a magnet interfere with the electronics in the machine?
Rarely. Do keep strong magnets away from Hall sensors, encoders and reed switches, unless they are designed to work with a magnet. See magnets and electronics.
