A custom magnetic flux controller is a concentrator, shield or core cut or formed to suit one coil. Fluxtrol soft magnetic composites (SMCs) are built for this: machinable Fluxtrol and Ferrotron blocks are fit to the inductor, and formable Alpha-form is molded in place. This page explains what controllers do, how they are made, and where to go for machining and assembly detail. Controller design is part of coil design and engineering .
What custom controllers do
Flux controllers direct current flow for a specific heating job. Placed near the copper, they concentrate the field at the coil face, shield nearby parts or redistribute the field. Fluxtrol benefits cited across its materials include higher heating efficiency, precise heat pattern control and longer coil life. In the hairpin coil example in the induction coils workflow , the section with Fluxtrol A heated more than the section without, because the SMC concentrated the field below the coil and redirected current to the bottom heat face.
Misplaced or lost controller material can produce a nonconforming part, so the ASM chapter stresses careful handling and secure attachment.
Machined controllers
Machinable grades are metal powder and plastic binder composites whose machinability falls between plastics and metals. They are strong in compression and weaker in tension or bending. Standard operations apply: blade and band saw cutting, milling, turning, drilling and grinding. CNC machining is recommended and water jet cutting works where practical. Optimal regimes should be established on samples before producing multiple parts. See machining soft magnetic composites and the safety notes in machining safety .
Formable controllers
Alpha-form is a formable SMC with a thermal-curing epoxy binder. It is applied to irregular coil geometries where machining is impractical, molded around the coil surface and cured in an oven. A video demonstrates efficiency gains with Alpha-form on a coil.
Attaching controllers to the coil
Adhesive bonding is the most common attachment method. The key decision is whether the bond only holds the controller in place or must also conduct heat into the water-cooled copper, which matters for heavily loaded coils and long cycles such as scanning. Adhesives should offer high adhesion strength, good thermal conductivity and high temperature resistance, since some copper zones can reach 200 C or more despite water cooling. Mechanical attachment is the most accurate and reliable method and tolerates thermal movement and vibration. Details are on assembling SMCs .
Protection and upkeep
In many applications the controller outlasts the copper, but it can fail from mechanical damage, overheating (for example, from insufficient cooling or glue cracks that separate it from the tubing), or process residue. Coatings protect against corrosion, and routine cleaning and visual inspection help. See protection and maintenance .
Get a controller for your coil
Send us the coil geometry, frequency and process and we will discuss material and shape. Contact Fluxtrol or order SMC materials .
Flux controller materials
Real-world results
Hairpin coil with and without Fluxtrol A
Fluxtrol A applied to half of a hairpin coil showed higher temperature and efficiency in simulation and testing.
- SMC concentrated the field below the coil
- SMC redirected current to the bottom heat face
Magnetic Flux Control in Induction Systems
Overview of concentration, shielding and redistribution of the magnetic field with SMC controllers.
- Accurate heat pattern control
- Improved inductor parameters