Flexible Magnets

Chapter 1: What is the principle of flexible magnets?

This chapter will cover the basics of flexible magnets, including their manufacturing process and functionality.

What are Flexible Magnets?

Flexible magnets are composite materials consisting of magnetic particles embedded in an elastomer matrix. They are created by combining rubber polymer resin with ferrite powder, which is then shaped through extrusion or rolling. The final steps involve magnetizing the material and laminating it with vinyl or adhesive.

Flexible magnets combine the elastic properties of rubber with the magnetic properties of elastomers, resulting in versatile materials suited for various technical applications.

As their name implies, flexible magnets are designed to be bendable and adaptable to meet specific application requirements. They can be easily cut into any shape, making them ideal for custom applications and specialized needs.

These magnets are used across a broad range of industries and sectors, including manufacturing, homes, schools, and businesses. Their adaptability allows them to fit diverse applications, with the ability to be shaped both during and after manufacturing. Flexible magnets are typically produced through calendering or extrusion processes.

Although flexible magnets offer distinct advantages over traditional solid magnets, such as flexibility and customizability, they may be less durable in certain applications. To ensure reliable performance, it's crucial to work with a reputable and experienced flexible magnet manufacturer who can recommend solutions tailored to the specific requirements of your application.

How Flexible Magnets Are Made

Flexible magnets are typically categorized into two types based on their manufacturing methods: magnetic sheets and extruded magnetic profiles.

Extruded Magnetic Profiles and Tapes

Flexible magnets can be extruded into profiles that can be coiled, typically in 33 or 98-foot (10 or 30 m) rolls, and then used for applications such as shower doors or refrigerator closures. The cross-section of an extruded magnetic profile can have detailed protrusions that allow it to slide into a mating aluminum extrusion and remain captive with only the front magnetized edge showing.

During manufacturing, the flexible, granular material is heated until it starts to melt. Then, it is forced under high pressure using a screw feed through a hardened die which has been electrical discharge machining (EDM) wire eroded to have the desired shape of the finished profile. As material continually flows from the die, it cools and then passes over a magnetizing fixture which magnetizes the strip with either a two-pole or multi-pole magnetic configuration.

Most flexible magnets are magnetized with stripes of magnetic poles on one face only. The other face is not magnetic. The extruded profile can be a rectangular section to produce a magnetic strip, often referred to as magnetic tape, and this can be laminated on the non-magnetized face with high-performance double-sided adhesive tape. Two identical strips can be magnetized with mating polarities so that when they attract each other, they line up and meet exactly; for example, one being NSNSN and the other SNSNS.

Flexible Magnetic Sheets

Magnetic sheets are created through a calendering process, typically measuring up to 24 inches (610 mm) in width and 98 feet (30 m) in length. Their thickness usually ranges from 0.02 to 0.03 inches (0.5 to 0.76 mm). These flexible sheets are commonly used in point-of-sale and advertising applications, such as vehicle graphics for taxis and driving school livery, which can be easily added or removed depending on the car's use.

This also applies to company cars that display logos, which may be removed over the weekends. For such applications, careful cleaning and flat storage are crucial to prevent ferrous particles from attracting to the magnetic surface and becoming trapped between the sign and the vehicle. Proper maintenance helps protect the car's paintwork.

Magnetic Graphics System

A magnetic graphics system allows for easy updates of variable information or graphic elements without needing to replace the entire sign or display.

Properties of Flexible Magnets

Powerful flexible magnetic sheeting is highly magnetized using a multiple pole magnetization pattern, ensuring that its magnetic strength is uniformly distributed across the surface. Generally, the thicker the material, the greater its magnetic strength.

Permanent magnetism is maintained as long as the material is not exposed to demagnetizing forces or stronger magnets.

In summary, flexible magnets are:

• Durable – They are easy to maintain and safe for finished surfaces. They contain no oils or plasticizers that can cause cracking, drying out, or surface migration when properly maintained.
• Safe – The material is lead-free and barium-free, making it a non-toxic substrate that is safe to work with and safe for consumers.
• Machinable – Easily drilled or cut with scissors, knife, die, punch, routers, or flatbed cutter to fit an application.
• Temperature Resistant – They can withstand limited exposure to temperatures ranging from -15°F to 160°F (-26 to 71°C) without demagnetizing.
• Chemical Resistant – They have excellent resistance against air, ozone, and steam. They are not affected by mineral oil, weak acid, lye, kerosene, or glycol but are slightly affected by nitric acid. Swelling can be caused by petrol, acetone, and alcohol (90%), and they can be dissolved by benzene and chlorinated solvents.

Chapter 2: What are magnetizers, magnetic labels, and magnetic paper?

This chapter will cover magnetizers, magnetic labels, and magnetic paper.

Magnetizers

Magnetizers are used to magnetize substrates that are initially unmagnetized, whether they are packed or printed. There are specialized magnetizers for high-quality commercial printers and handheld magnetizers that can be used with materials up to 30 mils thick.

Magnetic Labels

Magnetic labels offer versatile options and can be easily attached and removed from magnetic surfaces. They come in various forms, including pre-cut shapes, C-channel cardholders, write-on or wipe-off labels, flexible labels, inkjet-printable magnets, and document pockets.

Applications for magnetic labels include:

• Storage and store labeling
• Price marker holders
• Nameplates
• Control maps
• Flexible matched pole strips

Magnetic Paper

Magnetic paper is a composite material combining paper and rubber with a magnetic layer, typically available in letter-sized (A4) sheets for easy printing. It is commonly used for short-term advertising, educational tools, instant fridge magnets, business cards, and more. This material merges magnetic sheets with paper, offering an affordable and versatile option for various applications.

The magnetization of the paper is achieved through the rubber or plastic backing embedded with magnetized strontium ferrite powder or similar materials. This creates a flexible sheet of numerous small magnets. The thickness of the magnet paper influences its strength, though thicker types may be limited by printer compatibility. These sheets are most effective when applied to solid surfaces like metal or refrigerator doors. The material is also flexible and can be easily cut with scissors, making it possible to create custom magnets such as personalized name tags without needing bulk orders from traditional manufacturers.

Magnetic paper can come in glossy or matte finishes and is well-suited for high-quality prints. It can be used with most printers, handling one sheet at a time, with widths ranging from 0.6 to 2.4 inches (15 to 60 mm). While many suppliers offer magnetic paper in standard sizes, larger rolls are available for large-format printing. For optimal results, ensure the printing process is performed at the highest quality.

Disadvantages of Magnet Paper

Although magnetic paper is a versatile product for creating custom merchandise, there are some limitations to consider. The materials used in magnetic paper make it unsuitable for laser printers due to the heat involved in the printing process. Inkjet printers are more commonly used, but older models that generate significant heat may also pose problems, potentially distorting the printed image. Additionally, once printed, magnetic paper should be kept away from excessive ultraviolet (UV) radiation. While the material does not rust, UV exposure can make it brittle, potentially impacting its magnetic properties.

Flexible Magnet Products

Flexible magnets come in a variety of products, including the following:

Standard Energy Magnet Strip

Standard energy magnet strips are available in rolls or as individual units. These durable strips are suitable for both indoor and outdoor applications and can be customized in various orientations. They can also be laminated and magnetized according to specific requirements. Generally, the strength of flexible magnets is proportional to their thickness, with thicker strips providing stronger magnetic force. Common applications for magnet strips include package closures, toys and games, displays, arts and crafts, window and door seals, and labeling.

High-Energy Flexible Magnet Strip

Flexible magnet strips with high energy are typically employed in applications demanding superior strength and durability. These strips come in a range of both standard and custom dimensions and configurations. Additionally, they are offered in multiple magnetic orientations, enhancing their resistance to demagnetization, cracking, and chipping.

These magnet strips can be magnetized across their thickness in a diverse array of patterns. High-energy flexible magnet strips are utilized in various applications such as door latches, crafting projects, sensors, and magnetic assemblies.

Standard Flexible Magnetic Sheet

Standard flexible magnetic sheets typically feature a multi-pole magnetization design, providing a high holding strength of approximately 144 pounds (65 kg) per square foot. These sheets are generally stronger on one side, with the weaker side suitable for applying vinyl and adhesives. However, custom options are available with dual magnetization, offering equal magnetic strength on both sides. The sheets can be customized or die-cut to fit various shapes and sizes. They also come in a broad selection of colors, thicknesses, and adhesive types. Common uses for these flexible magnetic sheets include signage, craft projects, promotional symbols, and display boards.

Printable Wide-Format Magnet Sheet

Printable wide-format magnetic sheets are offered in sizes typically ranging from 40 to 60 inches (101.6 to 152.4 cm), making them ideal for wide-format printing applications. These sheets come with various laminate options, including matte white PVC, white dry erase surfaces, and other substrates upon request. Additionally, they can be combined with all-purpose tempera glue. Common applications for these printable wide-format magnet sheets include large-scale and interchangeable graphics for billboards, magnetic wall systems, control charts, and promotional items.

Recyclable Print Magnet Sheet

Recyclable magnetic print sheets are produced with a robust printable coating applied directly to the sheet, making them entirely recyclable and eliminating the need for a separate laminated surface. This design reduces disposal problems and allows for cleaner, more straightforward cutting due to the lack of adhesive. These sheets come in both standard and custom sizes and roll configurations. They are suitable for various applications, including indoor and outdoor displays, menu boards, interchangeable graphics, and vehicle signage.

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Chapter 3: What are the different types of flexible magnets?

Various types of flexible magnets include:

Magnetic Sheets or Rolls

Magnetic sheets are versatile printable materials used for applications such as banners, displays, vehicle signage, and artistic projects. Thinner versions are often utilized for crafts, such as bookmarks and refrigerator magnets. These sheets are made from calendared strontium ferrite magnetic compounds combined with a thermoplastic binder, resulting in a thin, flexible sheet with magnetic poles aligned on one side.

Flexible magnetic sheets have one magnetic surface that can attract to itself and are typically used against ferromagnetic surfaces like mild steel sheets. The maximum operating temperature is constrained by the binder; temperatures exceeding 176°F (80°C) can cause the binder to soften, leading to demagnetization as the magnetic properties are compromised.

Performance and Variations of Magnetic Sheets

Flexible magnetic sheets are available in various types and finishes. Basic flexible magnetic sheets do not include vinyl or adhesive layers, making them ideal for printing companies that wish to apply their own vinyl or adhesives to meet specific needs. In contrast, flexible magnetic sheets with an adhesive backing feature a standard acrylic adhesive layer on one side, allowing them to be applied to other materials or surfaces as needed, such as for creating lightweight magnetic components.

Vinyl-backed flexible magnetic sheets have a vinyl layer applied to the non-magnetic side, which can also be customized with printed designs for signage, advertising, or vehicle graphics. These sheets are used in various applications, including signage, banners, magnetic conversions, advertising, and display charts.

Magnetic sheets or rolls are made from synthetic, rubber-based materials that are permanently magnetized. They are widely used in the signage and graphics industries for their versatile applications.

Features of Magnetic Sheets

• Flexible and durable
• Retains magnetic properties (long service life)
• Weather-resistant
• Can be effortlessly cut, trimmed, punched, printed
• Excellent bond to metal faces
• Won't leave a residue when removed
• Easy usage in signage and display jobs
• Strontium ferrite material in a thermoplastic binder
• Maximum operating temperature 176 °F (80 °C)
• UV coating for cleaner conduct
• Regular shapes can be cut using affordable dies
• Available with plain, white, buff, or standard acrylic sticky backing

Printable Magnetic Paper & Sheets

Printable magnetic paper and sheets adhere effectively to ferrous metal surfaces such as steel office cabinets, shelving, and metal whiteboards. They are easy to cut using a guillotine or scissors and are compatible with both inkjet and laser printers.

To use, simply load the magnetic printable paper into an inkjet or laser printer to produce any desired magnetic sign. These magnetic printing materials are ideal for creating magnetic images and signs for various uses, such as magnetic organizers for home refrigerators or business cards, labels, barcodes, and invoices in an office setting.

Magnetic Strips

There are endless possibilities with magnetic strips. They can be laminated with various coatings, such as strong acrylic glue, for excellent outdoor weather capability.

Characteristics of Magnet Strips

Magnet strips consist of strong magnetic lines that cover the entire surface of flexible magnetic material. The greatest magnetic strength is typically found on the inner part of the roll. These strips are available in different forms, including standard and high-energy variations. They come in a variety of patterns to suit various applications, whether magnetized or not.

Physical Properties of Magnetic Strips

• Stability – excellent throughout
• Weather resistance – excellent
• Flexibility – excellent bending without cracking
• Viscosity – 3, 7 to 3, 8 g/cm3

Their operation is found in sales promotions, die-cut letters and figures, educational toys, display boards, decoration panels, nameplates, signage, advertising specialties, and games. They can also be used for pop-up displays, profiles for shower and refrigerator doors, bill displays, secondary glazing, visual planning, magnetic cutter racks, shelf labeling, etc.

Adhesive Magnetic Tape

Self-adhesive flexible magnetic tape features a magnetic surface on one side and a self-adhesive coating on the other.

This tape is commonly employed in merchandising, retail, and exhibition settings to showcase bills, photos, signs, and other promotional materials. It is also ideal for creating magnetic closures on printed items. Magnetic tapes come in two polarities, 'A' and 'B.' For proper attraction between two tapes, both polarities must be equally represented.

Various self-adhesive ferrous and steel tapes are used to create surfaces that can attract magnetic tape. For larger applications, it’s advisable to conduct tests as surface conditions can significantly impact adhesive performance.

The surface should be clean, dry, and free of dust for optimal results. It is important to clean the surface with a suitable cleaning agent and allow it to dry completely before application. The adhesive will adhere properly only if it has full contact with the surface, so rough or uneven surfaces should be avoided. Remove the protective film just before application, and avoid touching the adhesive side after the film has been removed.

Below are some examples of surfaces that have proven effective for self-adhesive neodymium magnets:

• Uncoated cardboard (gray)
• Carpeted cardboard (white)
• Laser printing paper
• Acrylic glass (PMMA)
• Wood

Pressing and Drying the Adhesive

After positioning the product, apply uniform pressure along its entire length to ensure a strong bond between the two surfaces. Allow the adhesive to cure for approximately 72 hours to achieve optimal bonding strength before removing the applied pressure.

The ideal temperature range for drying is between 69.8°F and 100.4°F (21°C and 38°C). Temperatures exceeding 176°F (80°C) can negatively impact the adhesive's performance. Additionally, factors such as ultraviolet radiation and humidity may affect the adhesive's effectiveness over time, even with proper application.

It's important to consider that adhesive products have a finite lifespan. Here are the expected lifetimes of some adhesive magnets:

• Magnets with adhesive film have a lifetime of approximately 12 months
• Magnets with adhesive foam have a lifetime of roughly 18 months
• Tenacious tapes have a lifespan of approximately 6 months

This information serves as a general guideline; the actual lifespan of adhesive bonds can vary based on factors such as the type of surface, sun exposure, and humidity. Under optimal conditions, the adhesive may last significantly longer.

Characteristics of Self-adhesive Magnets

Premium backing ensures superior adhesion and maximum holding power. Features include a fast-release tab for easy and efficient liner removal, and a robust composition of neodymium material for enhanced strength.

Attracting Ferromagnetic Surfaces with Self-adhesive Magnets

Neodymium disc magnets with adhesive backing are ideal for applications where a magnetic attraction to ferromagnetic surfaces, such as steel, is required. While these magnets may be positioned slightly apart, they should be close enough to attract each other. Utilizing alternating north and south poles can enhance the overall performance of the magnets, as this arrangement improves their interaction by attracting and reinforcing the magnetic fields around them.

Neodymium magnets exhibit magnetic properties that cause them to either attract or repel each other based on their arrangement. Attraction occurs when the north pole of one magnet faces the south pole of another, in line with the principle that like poles repel while opposite poles attract. Conversely, if north faces north or south faces south, the magnets will repel each other.

The arrangement of magnets in the final setup determines the required polarity for effective operation. Self-adhesive disc magnets are commonly used in various applications, including printing, packaging, arts and crafts, and folder closures. They are also useful for simpler home applications, such as door catches.

Chapter 4: What are the applications and uses of flexible magnets?

This section will explore the various applications and uses of flexible magnets.

Applications of Flexible Magnets

The applications of flexible magnets are:

Garage & Motor Repairs

Magnetic tools are widely utilized to save time and reduce stress in tasks related to vehicular maintenance, garage work, and similar service operations, as outlined below:

• Magnetic tool racks for tool storehouse and carrying
• Retrieval tools for reacquiring lost screws, fixings, and tools from hard-to-access places
• Notice boards and displays
• Attachment of temporary signage like van outfit or number plates
• Sweeping to clear bottom spaces of ferrous items
• Reinforcements for inspection lights
• Lifts for the movement of heavy steel components

Retail and Display

Magnetic materials and flexible magnets are employed in various display applications to simplify installation and minimize damage upon removal.

• Removing banners from ceiling supports
• Mounting removable wall signage
• Mounting plates on twisted shells
• Shelf and position markings
• Storing shop fitter tools
• Temporary holding or hanging displays in showrooms or events
• Rubber carpeted magnets for protecting face finishes

Storehouse & Distribution Centers

Flexible magnets can be a cost-effective and quick solution for the following applications:

• Notice board and planner displays
• Easy attach-and-remove raging bay and shelving labels
• Attaching temporary vehicle or fork truck signage
• Sweeping vehicle bays or auto parks clear of ferrous items
• General tool storage
• Retrieval of lost items from inaccessible places

Using adhesive magnets enables innovative designs and manufacturing techniques that are not feasible with brittle or rigid materials. Flexible magnetic products can be twisted, cut, bent, coiled, punched, and shaped without losing their magnetic properties. For instance, bending can create ring magnets, commonly used in small direct current motors. These magnets are also easy to machine with conventional tools.

Conclusion

Flexible magnets are composite materials with magnetic elements arranged in an elastomer matrix. They're made from a combination of rubber polymer resin and ferrite powder by forming them through extrusion or rollers and finally magnetizing and laminating them with vinyl or glue. The compound materials bring together rubber elastic properties and elastomer magnetic properties to bring out flexible materials that are useful in multiple specialized applications. Flexible magnets have been of great help to humanity over the generations, and their application continues to be of great value in multiple fields and sectors.

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