Applications | Performance Knowledge | Applying Fluxtrol to Induction Coils | Custom Fabrication

Progressive induction hardening of ball screw shaft with Fluxtrol concentrator 

What is Induction Heating?

Induction Heating is an electromagnetic heating method of electrically conductive bodies, which absorb energy from an alternating magnetic field, generated by induction coil (inductor). 

How Does Induction Heating Work?

When an alternating (varying) electrical current flows through an inductor (or coil) an alternating magnetic field is generated in the surrounding space. If an electrically conductive body (part or workpiece) is placed in this magnetic field, eddy currents are induced in its volume generating heat.

In magnetic materials additional heating occurs due to the orientation of the magnetic domains according to field direction (hystersis losses). Induction heating is caused by the thermal effect of strong eddy currents induced by magnetic alternating flux. The lines of magnetic flux produced by the coil current must be closed. A sufficient part of coil ampere-turns must be consumed for flux pushing through the magnetic resistance of the back path. Hence, excessive current must flow in the coil to produce the required flux resulting in additional losses in the coil, supplying circuit and power supply. A typical inductor's magnetic field is distributed over a large area which causes a much wider temperature effected area resulting in undesired heating of part or workpiece in close proximity to the coil.

What is a Fluxtrol Concentrator?

Fluxtrol materials are soft magnetic composites made of magnetic powdered metals and dielectric binders by compacting at high pressures with subsequent thermal treatment.  They are used for magnetic flux control (concentrating, shielding or modifying), essentially capturing the alternating magnetic field and re-directing or focusing it to the desired area of the workpiece (or part). These materials are characterized as having low electrical conductivity, high magnetic permeability and low magnetic losses.

Magnetic Flux Control is a generic term for modification of induction coil magnetic flux by means of installation of magnetic templates (magnetic flux controllers).  Magnetic controllers may signifcantly change magnetic field pattern and coil parameters;  their application must be considered as a part of the whole induiction system design.

How Does Fluxtrol Concentrator Work?

Magnetic flux always flows around an inductor (or coil) in closed loop path. Fluxtrol soft magnetic materials provide an easier way for the magnetic field to travel than traveling in air, thus increasing field intensity or localizing the magnetic field on the electrically conductive body surface (i.e., part or workpiece) in close proximity. 

Fluxtrol flux concentrators strongly reduce the back-path magnetic resistance, due to the high permeability of our soft magnetic material and concentrate the induced power in the critical area of the workpiece. When applied to an inductor (or coil), Fluxtrol flux concentrators provide increased heating in desirable zones and reduce heating in undesirable zones. Magnetic field distribution and heat patterns are controllable, process efficiencies increase, cycle times decrease and energy savings result from using Fluxtrol flux concentrators. In many cases, the application of our proprietary soft magnetic materials, make a seemingly impossible task a manageable one! 

Magnetic flux controllers play differenct roles they are also called concentrators, cores or shields depending on application.

Our latest soft magnetic materials feature higher temperature resistance, improved mechanical strength, excellent machinability and a broader range of capability allowing for direct replacement of laminations and ferrites with improved results.