Magnetic Element Design: Magnet Characteristic Optimization for Manufacturability Enhancements

Designers and engineers that want to include a magnet into their software are sometimes not totally conscious of the mechanical traits of magnetic alloys.  Options which can be generally specified and produced on supplies resembling delicate metal, stainless-steel, aluminum, or brass will be very troublesome to supply on a magnet or included into magnet assemblies.

A lot of the problem relies on the composition of the magnetic alloy which is characteristically hard and brittle.  Hard and brittle is a short phrase that may be repeated fairly a bit when discussing the characteristics of magnets.

Default title-block pitfalls:

Many magnet drawings have ‘title-block default’ specs and tolerances which, whereas will be utilized, might add prices that aren’t warranted.  Among the options and geometric dimensioning and tolerancing (generally known as GD&T) that’s usually managed by default within the title-block are floor end, dimensional/angular tolerances, and radio/fillets. These “defaults” will be provided, however one should query if they’re really essential to the match and performance of the appliance.  They need to be utilized purposefully and never be handled as “boilerplate,” as integrating them might add value.

Floor end and edge breaks – Alloy manufacturing technique:

Most permanent magnets are produced by both casting or sintering processes.  Within the absence of dimensional management, the alloy is left in an ‘as solid’ or ‘as sintered’ situation.  Abrasive grinding is the commonest technique of attaining higher floor finishes.  Edge break necessities are utilized by abrasively tumbling or grinding.  Easy deburring operations, generally used on standard supplies, aren’t attainable as a result of hardness and brittle nature of the fabric.  For that reason, we’d warning designers in opposition to arbitrarily tight tolerances on edge breaks and different options that don’t affect match and performance.

Corrosion inhibitors:

Corrosion prevention and improved beauty look are two distinguished advantages which can be a result of coating or plating a magnet.  Plating processes have been optimized for a lot of magnetic alloys; nonetheless, in contrast to typical steel plating choices for different business supplies, Service Codes (SC), indicating efficiency in varied environments, and adherence to an affiliation specification aren’t at all times accessible.  No matter the kind of plating, magnets shouldn’t be designed to work in aggressive operational environments.

Mechanical options:

Fabricated options resembling holes, shoulders, tapers, and grooves will be built-in into lots of the magnetic alloys we provide.  Normally the required tolerance for these options don’t enable for casting or sintering them immediately and they’re usually produced by abrasively grinding or electrical discharge machining (EDM).  Low inventory removing throughout grinding, as a result of the fragility of the alloy, provides value.  Additionally, the excessive resistivity of magnet alloy leads to lengthy EDM burn occasions and undesirable ID tapers which require further fabrication time to right and due to this fact add value to completed items.

One is aware of warning, everlasting magnets are very liable to fracturing when flexed or confused in tensile.  No matter whether or not the magnets have easy or extra difficult options, they shouldn’t be specified or used as a structural design factor.

Design consideration:

Though the fabrication strategies mentioned earlier exist as choices to supply complicated options on magnets, it could make sense to keep away from these processes and combine a much less complicated magnet.  Typically a cursory assessment of a magnet drawing is sufficient to present beneficial suggestions on what’s and what isn’t a possible magnet.  Magnetics design engineers can efficiently help your design workforce in creating a producing method that yields a magnet assembly the appliance necessities whereas mitigating pointless prices and longer lead occasions.