High Permeability Non-Sintered Flux Concentrators for Inductive Coupling

Ragan Technologies, Inc. (RTI) has developed a process for compacting powders of magnetic materials such as iron or ferrite into sheets of highly compacted particles.

These sheets are intended for use in inductive coupling applications.

The principal advantages of this process over powder compaction are as follows:

• Provides higher density,
• Particles are moving dynamically during compaction allowing them to move into a more optimum fit with the surrounding particles,
• Tighter grain boundaries are achieve providing higher magnetic permeability,
• The process works best in applications where the Z-axis is small compared to the X and Y. For example: if the sheet is 12 inches wide and 1/16” thick and 100 feet long, it would be difficult (impossible) to powder press. However, the RTI High Shear Compaction process does this easily and at high production rates,
• Lower production costs due to the high efficiency and low capital equipment cost of the process,
• Resulting sheets are sufficiently ductile to be cut to size from the sheet, and
• The sheets have a degree of flexibility to allow them to fit into non-planar geometries.

RTI would welcome the opportunity to prepare demonstration samples using the High Shear Compaction (HSC) process.

Results of Previous Tests:

Manufacturing of Magnetic Flux Focusing Plates for Portable Device
Wireless Battery Charging

Synopsys:

Ragan Technologies has applied a proprietary process it has developed for making high strength ceramic armor plates to the magnetic materials needed for wireless battery charging. The resulting parts have higher performance and lower cost than all other competing processes we have tested.

Background:

The adoption of inductive coupling for battery charging of cell phones and other portable electronics requires an efficient “channeling” of the magnetic field produced by the charging device into the power receptor of the portable device.

The magnetic characteristics of the magnetic field focusing components used to do the “channeling” will determine how much energy can be transferred in a given time and how large the component needs to be to meet an acceptable charge time.

The desired magnetic specifications have been difficult to meet with available manufacturing processes.

Ragan Technologies has applied a process it has developed for making high strength ceramic armor plates to the magnetic materials needed for the magnetic flux focus.

This unconventional processing has yielded magnetic performance that exceeds that of the conventional methods of manufacturing. These processes are proprietary to RTI and provide a unique opportunity to maintain a competitive advantage in this market as a result of having the lowest cost and perhaps only method capable of producing the product.

Technology:

Magnetic flux focusing devices and ceramic armor are both produced from powdered raw materials. In both cases, the ultimate performance depends on how intimately the particles can be joined into a solid. Various processes are used for pressing the particles together. Generally an organic resin of some kind is used to bind the particles together. Think of particleboard as an example on a macro scale.

The key to higher performance is to minimize the collective effect of the presence of the binder and imperfections in the joining of the particles. Many years of research have been spent by hundreds of companies and research labs around the world, all aimed at this seemingly simple objective. As progress was made the materials have moved closer to their theoretically perfect density.

Very expensive processes are available that can achieve nearly perfect density, but what is needed is a process that can achieve the high density while lowering production processing costs.

The RTI process achieves the necessary performance with a two-step approach. First, RTI has developed a binding polymer that can achieve the necessary binding properties with a much lower concentration than other polymers commonly used.

Second, RTI uses its proprietary High Shear Compaction (HSC) process to convert the powder into an extremely dense tape. The HSC process is uniquely efficient for high volume production compared to tape casting, powder compaction or extrusion.

This process is continuous and very efficient. The powder and the binder are mixed at very low binder concentrations, less than 1.8wt%. The material is formed and densified at rates as high as 10 feet per minute at greater than one foot. As the material is produced it is laminated to a film of Kapton tape on one side or both. Once produced, the flexible sheet is easily punched into the final configuration.