Magnetic device adapters with controlled magnetic anisotropy
One of the most important parts of every magnetic clamping or handling device is its adapter. Adapter has to form an optimum way for the working magnetic flux from the device energy source to the steel piece to be clamped or transported magnetically. At the same time adapter has to minimize magnetic losses by limiting magnetic leakage flux through its structure.
Below we present the results of the International Project “Research of Soft Magnetic Materials with Controlled Anisotropy for Magnetic Device Adapters”, performed by DVM together with Material Science Institute of NAS, Ukraine.
Anisotropic electrotechnical steel in sheet or tape form is widely used in the industry, where the intensity of magnetization in different directors changes several times. But use of anisotropic steels is always associated with technical difficulties and huge (up to 40%) material losses.
Modern powder metallurgy allows changing the macro- and microstructure of material in the predetermined directions, as well as its properties along with significant cost reduction due to the waste less technology.
As part of the presented project we were developing powder soft magnetic materials with controlled magnetic anisotropy by investigating laminated-gradient structures in ferromagnetic matrix made of iron powder or materials on its base.
Iron powder cold pressing, rolling and impregnation were used to develop ferromagnetic macrostructures in a form of laminated components, located in different directions.
Created technology allows us to control location of separate layers in order to change material magnetic properties in different directions. Ferromagnetic layers can be alternated with interlayers made of nonmagnetic metals, ceramic or organic materials.
Iron powder containing less than 0.02% carbon, as well as iron alloys with phosphorus and silicon were used as ferromagnetic components. Materials for interlayers were copper, nickel, high temperature glasses and organic resin.
The experiments have shown that at optimum ratio between the thickness and interlayers’ location the following magnetic characteristics of composite material can be obtained:
|Saturation induction, Bmax||≤ 1,8 T|
|Ratio of magnetic resistance in different directions||≥ 1: 10|
Newly created composite materials were successfully tested as top plates of magnetic chucks for surface grinding machines and as pole plates for magnetic lifting and handling devices.
We can state the significant technological possibilities increase of these magnetic devices due to more than 15% magnetic force increase, more than 12% reduction in magnetic losses and the possibility to magnetically attract much wider range of steel parts of different shapes and sizes.
All of the above advantages are based on the so called “self-adjusted” poles effect, where the size and form of active magnetic poles on device working surface directly depends on the size and form of the workpiece to be attracted.
Created powder metallurgical technology for producing soft magnetic materials with controlled anisotropy is 100% environmental friendly and uses waste less manufacturing process and inexpensive initial materials.
These newly developed anisotropic materials can be used successfully in many innovative magnetic devices.