Multiple key manufacturing phases and countless sub-steps create high-quality, high-tech Neo magnets. Hence, each step is critical and a necessary aspect of a highly tuned process.
This phase involves the inspection of raw materials needed for Neodymium magnet manufacturing. The samples are inspected, cleaned, and prepared for alloyed preparation.
Small amounts of additional metals are applied to NdFeB alloy throughout the alloying process to refine and change the microstructure of the final product, boosting its magnetic characteristics and the impact of subsequent procedures.
Melting and strip casting of alloyed NdFeB is now possible. The products are heated in a vacuum furnace, and then a stream of molten metal is pushed under pressure onto a cooled drum. As a result, it is quickly cooled at 100,000 degrees per second. The rapid cooling creates extremely tiny metal grains, which simplify and improve the impact of the downstream processing. Small grains are also a key component in the production of high-quality magnets.
Milling grinds NdFeB metal into powder using a high-speed cyclonic inert gas. The metal collides with other metal powder particles within the cyclone. The cyclone automatically classifies particles by size as they pass through the system, resulting in a narrow – and highly desirable – particle size distribution.
The cyclonic airflow automatically separates the particles because various particle sizes have varying aerodynamics. It prevents the material from coming into touch with the walls of the pressure vessel owing to the gas flow pressure and velocity.
Before entering the automated press, the powder is maintained in an inert gas environment and handled in glove boxes. The powder is crushed between plates in a mold while subjected to a high magnetic field, forming a material block. The magnetic field aligns the grains such that the magnetic poles stay aligned in the intended direction throughout the remainder of the processing stages.
The magnetic field may be directed in two directions: 1) parallel to the block and 2) perpendicular to the block.
To produce the greatest sintered neodymium magnets, they are typically pushed perpendicular to the block (strongest north-south magnetization)
Sintering & Annealing
The pressed block is taken from the bag and then sintered. Sintering is a technique in which the blocks are heated to just below the melting point of the metal in a furnace. At temperatures over 1000oC, the individual atoms move a lot, allowing the blocks to achieve their full magnetic and mechanical capabilities. The magnetic domains retain their original orientation after sintering. The blocks have reached a total density and shrunk to their ultimate size at this temperature.
Because of the pent-up strains in the metal caused by the sintering action, the blocks are heat-treated again in a step pattern at lower temperatures to alleviate the stresses. The blocks produced are ramped to a high holding temperature for a predetermined time before being ramped down to a lower holding temperature. Once the holding period has been reached, the blocks are gradually cooled to room temperature.
Because of the above procedures, NdFeB magnets have gained much value. Cutting, machining, and grinding are all done following a precise control plan, and waste is kept to a minimum by design.
Wire cutting is done using extremely tiny wire to reduce incision losses. Close controls throughout the preceding steps reduce machining and grinding. Waste is repurposed and recycled.
Before leaving the facility, most Neodymium magnets now get a final surface treatment. The standard treatment is a nickel-copper-nickel electroplate, which protects the neodymium magnet against corrosion in most common situations.
For various reasons, some end customers want no coating at all. There are various options for coatings, but nickel is the most common and usually preferred. Our nickel-plated magnets are triple plated with nickel, copper, and nickel layers. This triple coating makes our neodymium magnets much more durable than the common single nickel-plated magnets. Other layer options are zinc, tin, copper, epoxy, silver, and gold. Our gold-plated neodymium magnets are quadruple plated with nickel-copper-nickel and a top coating of gold. Ni+Cu+Ni, Epoxy, Zn, Color Zn, and Passivation are the most ordered coatings. For more information regarding our coating offers, please visit our Coating Page.
Several metrics, such as pulling force and magnetic field strength, contribute to a magnet’s strength. Each of these elements will need to be tested and quantified.
Magnetizing is one of the last processes. The material is put within an electric coil and briefly activated to generate a powerful magnetic field. The magnetic field in the magnet continues after the coil is de-energized.
After plating, the completed material is magnetized, which involves putting it within a coil that creates a magnetic field three times stronger than the needed strength of the magnet when an electric current is sent through it.
Magnet material is tested and evaluated practically every manufacturing step, and records of every data point are retained. With such stringent testing requirements, ROBO Magnetic maintains a large inventory of test equipment in-house to maintain and enhance product quality, manufacturing efficiency, and cost. Thorough testing ensures that only high-quality items are supplied to customers.
Neodymium magnets should be kept in a low-humidity, low-temperature environment. The magnetic neodymium alloy is very powerful and will attract ferrous particles from the surrounding air and surfaces. These particles will gather and appear on the surface of the magnet or package as little “hairs.” Keep the neodymium magnets in tight, clean containers and leave them in their original ROBO Magnetic packing to avoid accumulating dirt. With all spacers in place, the neodymium magnets should keep attracting. Metal shelves with insufficient clearance may cause magnets to leap or move when accessible. Keep magnetic materials away from sensitive electronics, cathode ray tubes (CRT), and magnetic storage media. Neodymium magnets of different alloys may need to be buffered from each other due to demagnetizing effects.
What Sets Neodymium Different from Other Magnets?
Neodymium magnets are rare-earth magnets that include neodymium, iron, and boron. In contrast, ordinary magnets are typically ceramic (or ferrite) magnets that contain iron(III) oxide and are used for everyday tasks. As a result, the primary factor differentiating between a neodymium magnet and a conventional magnet is the essential components of these magnets. The characteristics of neodymium and ordinary magnets vary significantly due to the above composition. Neodymium magnets have very high remanence, coercivity, and energy products, while regular magnets have low remanence and energy products. However, ferrite magnets are classified into two categories based on their coercivity: hard ferrites and soft ferrites (high and low, respectively). Furthermore, the Curie temperature of neodymium magnets is lower than that of conventional magnets.