Rubber Coated Magnets | WZ Magnetics

Overview of Rubber Coated Magnets

Although they share a similar name, rubber magnets and rubber coated magnets differ significantly in their structure, magnetic strength, and applications.

Rubber magnets are created by blending magnetic powder with a rubber binder, producing a flexible material that can be easily shaped or cut. These magnets are relatively low in magnetic strength and are commonly used in applications such as refrigerator magnets, flexible magnetic sheets for advertising, and educational tools.

On the other hand, rubber coated magnets, also known as rubber covered or rubberized magnets, feature a magnetic core encased in a durable rubber layer. This protective rubber casing not only shields the magnet from environmental damage but also prevents scratches on surfaces it contacts. Rubber coated magnet is highly magnetic and weather-resistant, making it ideal for indoor and outdoor applications requiring strong pull force along with surface protection.

Magnetic Circuit in Rubber Coated Magnet

Rubber coated magnets consist of three primary components: a ferromagnetic steel plate, Neodymium magnets, and a durable rubber casing. Functioning similarly to pot magnets as magnetic holding assemblies, rubber coated magnets stand out for their unique advantages, including enhanced surface protection, superior resistance to corrosion and impact, and increased friction—benefits attributed to their rubber covering.

The rubber casing introduces a distinctive magnetic circuit within rubber coated magnets, setting them apart from traditional pot magnets. This circuit is constructed with Neodymium magnets and a ferromagnetic steel plate. Typically, disc-shaped Neodymium magnets are arranged on the steel plate in an alternating pole pattern to optimize magnetic performance.

The pull force of rubber coated magnets can be fine-tuned by optimizing the magnetic circuit, while the rubber material is tailored to meet specific requirements. This collaborative design ensures these magnets can be precisely adjusted to suit a wide range of applications, offering unparalleled versatility and performance.

Magnetic Circuit in Rubber Coated Magnets-updated

How is Rubber Coated Magnet Made?

The rubber casing of rubber coated magnets provides more than just protection against environmental damage and surface scratches—it also offers superior slip resistance through the friction generated between the rubber and the working surface. While the magnetic pull force and surface protection are often highlighted, the durability and friction coefficient, influenced by the rubber material, are equally critical yet frequently overlooked.

The production of rubber coated magnets begins with the placement of disc-shaped magnets onto a ferromagnetic steel plate, followed by the encapsulation process. This encapsulation is achieved through either vulcanization or injection molding:

Vulcanization: Originally the standard method, vulcanization uses various rubber materials such as ethylene propylene diene monomer (EPDM) rubber, high-temperature vulcanized (HTV) silicone rubber, nitrile butadiene rubber (NBR), and fluorine rubber. EPDM is prized for its durability, NBR for its oil resistance, and fluorine rubber for combining both advantages. Despite its effectiveness, vulcanization is often criticized for its slower production rates and higher material costs.
Injection Molding: This more efficient alternative involves a two-step process. First, a rubber part with a cavity is molded to house the magnetic assembly. The assembly and initial rubber part are then placed in a second mold, where another rubber layer is injected, completely encapsulating and bonding with the first part. To achieve performance similar to vulcanization, thermoplastic vulcanizates (TPV) are often used. However, some manufacturers, seeking cost reductions, opt for less durable materials such as thermoplastic rubber (TPR) or thermoplastic elastomer (TPE), compromising durability and slip resistance.

When selecting rubber materials, customers should carefully consider their application requirements to ensure the chosen material meets the necessary performance and durability standards.

Common Types of Rubber Coated Magnet

Rubber coated magnet comes in a variety of designs to suit diverse applications. Common options include magnets with external threaded studs, internal threads, and countersunk or counterbore holes for secure mounting. Other variations, such as rubber coated hook magnets, eyelet magnets, and magnets with cable holders, are tailored for specific uses like hanging, securing cables, or attaching ropes. For heavy-duty needs, high-strength rubber coated magnet is available, while rectangular versions with one or two internal threaded holes provide unique solutions for specialized applications.