1. Raw material selection: the key to determining the performance of rubber magnets

Rubber magnets are mainly made of magnetic powder and polymer rubber substrate. Commonly used magnetic powders are ferrite (such as SrO·6Fe₂O₃) or rare earth magnetic powders, among which ferrite is currently the most common choice, taking into account both cost-effectiveness and magnetic properties. The content of magnetic powder directly affects the magnetic force of the final product. The ratio is usually between 70% and 90%. The higher the content, the stronger the magnetic properties, but the softness will decrease.

The substrate is mostly NBR (nitrile rubber) or CPE (chlorinated polyethylene), which have good oil resistance and weather resistance respectively. Different application scenarios have different requirements for flexibility, temperature resistance, and aging resistance, so materials must be selected accurately according to customer purposes. For example, rubber magnets used for indoor advertising magnets pay more attention to softness and printing adaptability; rubber magnets used for motor rotor induction must have higher magnetic properties.

2. Customer demand analysis: customized specification confirmation process

Customized production first requires clear and accurate demand communication.

In actual orders, customers will put forward the following main requirements:

• Size and shape: Is it a sheet, coil or special-shaped punching part? What is the size tolerance range?
• Thickness: Common thickness ranges from 0.5mm to 10mm, and different thicknesses have a significant impact on magnetic force and flexibility.
• Surface treatment: Is it necessary to cover PVC film, double-sided tape or surface printing?
• Magnetic force requirements: Gauss values are usually used to express magnetic flux density, such as ≥1000 Gauss.
• Magnetic method: single-sided multi-pole magnetization, radial magnetization or special requirements for charging and demagnetization.

A professional manufacturer usually confirms every detail with the customer through drawings, samples, and even video conferences to prevent deviations in the production process.

3. Production process: the whole process from mixing to molding

The production process of rubber magnets can be summarized into five steps:

Raw material mixing

Mix the magnetic powder with rubber in a precise ratio and mix it at high temperature through an internal mixer to ensure that the magnetic powder is evenly dispersed.

Calendering molding

The mixed rubber material is extruded into sheets or coils of the required thickness on a calender, and the surface flatness must be controlled within ±0.05mm.

Cutting and punching

Carry out vertical and horizontal cutting or mold punching according to the customer’s size, and complex shapes require customized knife molds.

Magnetization treatment

The product is magnetized by pulse magnetization equipment, and the magnetic pole arrangement and pole pitch can be set according to customer needs.

Coating and printing

If the customer needs lamination or printing Logo, the surface treatment is completed at this stage.

Each of the above processes has a direct impact on the quality of the product, so the equipment accuracy and operating specifications are very critical.

4. Magnetization method: the core process that affects the performance of use

The magnetization method of rubber magnets is one of the most important links in customization, which directly determines the usage scenario and performance. There are mainly the following types:

Single-sided multi-pole magnetization

The magnetic force is concentrated on one side, which is often used in refrigerator magnets and advertising magnetic strips, which is convenient for adsorption with metal surfaces.

Double-sided multi-pole magnetization

There is magnetic force on both sides, which can be used for magnetic sealing strips or bidirectional adsorption.

Radial magnetization

Mainly used in products that require circumferential magnetic fields such as motor rotors.

Directional charging and demagnetization

In some special applications, such as sensor matching, it is necessary to first magnetize and then partially demagnetize to produce a specific induction effect.

Usually, different magnetization methods require different coil molds and magnetization power supplies, and manufacturers must have corresponding process capabilities.

5. Inspection and quality control: ensure that each batch of products is stable and consistent

In order to ensure that every piece of rubber magnet received by the customer meets the standards, a strict quality inspection process is essential. The main inspection items include:

Size and flatness

Electronic calipers and flatness gauges are used to ensure that the thickness, width and length meet the tolerance.

Magnetic flux density detection

Use a Gauss meter to sample the surface magnetism of each batch to check whether it meets customer requirements.

Peel strength and flexibility test

Laminated products need to test the peel strength to prevent delamination during use.

Aging resistance and temperature resistance test

Weather resistance, high and low temperature resistance performance inspection for special requirements.

Conclusion

From the scientific selection of raw materials, to the precise control of the production process, to rigorous quality inspection, the production of customized rubber magnets is a systematic project that combines technology and management. Behind every seemingly ordinary magnetic film is a deep understanding of performance, process and customer needs. If you need to learn more about or customize rubber magnet products, please visit the JLMAG website to provide you with professional consultation and solutions.

4. Future Outlook: Create a circular economy for magnets

Although magnets cannot truly achieve “infinite recycling” at present, through technological progress and policy promotion, we are gradually moving towards a new stage of “efficient recycling + high-value reuse”.

As a member of the permanent magnet industry, we advocate:

Consider recyclability at the product design stage

Strengthen the construction of recycling channels for old magnets

Adopt environmentally friendly recycling processes

Improve users’ awareness of magnet recycling

 

In summary, we can know that although magnets cannot be “infinitely recycled”, their materials have high recycling potential. We hope to achieve efficient regeneration of permanent magnetic materials through reasonable design, scientific recycling technology and users’ environmental awareness, and contribute to the development of green industries.

First of all, compared with traditional ferrite permanent magnets, ferrite permanent magnets are cheap and have good chemical stability, but their maximum magnetic energy product is low and their coercive force is relatively weak. This makes ferrite permanent magnets widely used in some occasions where magnetic properties are not required, such as ordinary speakers, telephones and other products. NdFeB permanent magnets have extremely high magnetic energy product and coercive force, can generate strong magnetic fields, and can be used to manufacture high-performance motors, nuclear magnetic resonance imaging equipment, etc. These devices have extremely demanding requirements on the magnetic properties of magnets, and ferrite permanent magnets are difficult to meet.

Alnico permanent magnets have good temperature stability and high remanence. They are relatively stable in high temperature environments and are often used in some instruments that are sensitive to temperature changes. However, their coercivity is relatively low and they are easily demagnetized by external magnetic fields. In contrast, NdFeB permanent magnets have high coercivity and strong anti-demagnetization ability, and can maintain stable magnetism even in complex magnetic field environments. However, the temperature stability of NdFeB permanent magnets is slightly inferior. When used in high temperature environments, special temperature compensation measures need to be taken to ensure that their performance is not affected.

When faced with the problem of demagnetization of NdFeB permanent magnets, a variety of solutions can be adopted. On the one hand, from the material level optimization, by improving the formula and production process, adding appropriate amounts of other elements to NdFeB permanent magnets, such as rare earth elements such as dysprosium and terbium, can effectively improve their coercivity at high temperatures and enhance their anti-demagnetization performance. On the other hand, in actual application scenarios, physical protection measures can be used. For example, NdFeB permanent magnets are equipped with heat dissipation devices. When the application environment temperature is too high, the heat can be dissipated in time to avoid demagnetization caused by excessive temperature. For magnet applications with current passing through, the circuit should be reasonably designed to ensure the current stability and prevent demagnetization caused by excessive current shock.

Secondly, from a cost perspective, NdFeB permanent magnets contain rare earth elements such as neodymium, so their raw material costs are relatively high. Ferrite permanent magnets have a low cost due to their abundant raw materials and simple production process. The cost of Alnico permanent magnets is between the two. This also leads to the fact that ferrite permanent magnets are more popular in some large-scale application scenarios that are cost-sensitive and have low requirements for magnetic properties; while in high-end fields where performance requirements are extremely high and cost is not the primary consideration, NdFeB permanent magnets dominate with their excellent performance.

In general, we can conclude from the above that NdFeB permanent magnets have significant advantages in magnetic properties, which makes them play an irreplaceable role in many high-end technology fields. Although they have certain shortcomings in cost and temperature stability, these problems are gradually being improved with the continuous advancement of technology. Other types of permanent magnets have also found suitable application spaces in different fields due to their unique performance characteristics.

If you are selecting NdFeB permanent magnets or want to know more, welcome to visit JLMAG’s website. We provide you with high-quality NdFeB permanent magnets wholesale, as well as bring you more permanent magnet and rare earth information.