Plastomagnets

Introduction

Permanent magnets are manufactured either by traditional metal casting or sintering – the "ceramic" technology. However, both methods have their limitations in particular with regard to shape, complexity of the product and the achieved precision of dimensions.
The pressure on increasing productivity and the growing demands on precision led to the development of a special technology of permanent magnets, similar to the manufacture of plastics. A magnetic material in powder form is mixed with a powder binder on a base of resins and then pressed and hardened by heat, alternatively injected at heat in a semi-liquid state.
This enables the manufacturing of complicated magnet shapes with a precision of up to 0.01 mm (!), and it is even possible to manufacture, within a single production operation, a magnet-rotor together with a plastic pinion, a magnet with a pressed-in shaft, etc. During mass production productivity increases many times.
 

Properties

Plastomagnets are always made to order, so that the final shape precisely corresponds with the customer’s requirements. When designing a magnet, it should be taken into consideration that the magnetic properties are slightly lower than in an equivalent traditional magnet from the same material, as the volume share of the magnetic powder reaches "only" 60 to 80%.
Simpler parts are made by pressing, when higher magnetic parameters are achieved. Complicated shapes are made by injecting at increased temperatures, which is also less expensive.
 

Applications

Plastomagnets are used especially in industrial mass production. The greatest economic benefit is gained with series exceeding 10 000 units.
 

Magnetické vlastnosti - Plastomagnety lisované

Magnetic properties – Injected plastomagnets