Flexible Magnets

Chapter 1: Principle of Flexible Magnets

This chapter will discuss what flexible magnets are, their manufacturing process, and how they function.

What are Flexible Magnets?

Flexible magnets are composite materials with magnetic components arranged in an elastomer matrix. They are made from a combination of rubber polymer resin and ferrite powder by forming it through extrusion or rollers and finally magnetizing and laminating it with vinyl or an adhesive.

The composite materials bring together rubber elastic properties and elastomer magnetic properties to bring out flexible materials that are useful in many technical applications.

Flexible magnets are one of the most preferred types of magnets. Their name suggests they are flexible, meaning that they can be made to bend. They can also be manipulated to fit specific application requirements. In addition, flexible magnets can be cut into any shape, making them ideal for custom requirements and applications.

Flexible magnets are used in many different industries and sectors. They cover a wide range, from manufacturing industries to homes, schools, and many businesses. Flexible magnets can fit into different applications because they can be manipulated and shaped during and after manufacturing to fit a specified need. They are usually made by two processes, calendering and extrusion.

While flexible magnets offer several unique advantages over more traditional, solid magnets, they are also less durable, making them a liability in certain applications. The best way to ensure reliable flexible magnets is to find a trusted and experienced flexible magnet manufacturer who understands the requirements of the application in order to propose the right solution.

How Flexible Magnets Are Made

Two categories of flexible magnets are made in different ways: 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 produced using a calendering process; most tend to be 24 inches (610mm) wide with a length of up to 98 feet (30 m). The thickness of flexible magnetic sheets usually ranges from 0.02 to 0.03 inches (0.5 to 0.76mm). Flexible sheets are often used for point of sale and advertising, particularly for cars. Taxis and driving school livery can be added and removed when the car is used privately.

The same is true for company cars that display company logos removed for the weekends. In these applications, meticulous cleaning and flat storage are essential to prevent ferrous particles from getting attracted to the magnetic surface of the sign and then becoming trapped between the sign and the car. Good housekeeping will maintain the car’s paintwork.

Magnetic Graphics System

A magnetic graphics system can easily change out variable information or graphic elements without changing the entire sign or graphic display.

Properties of Flexible Magnets

Powerful, flexible magnetic sheeting is supersaturated with magnetism in a multiple pole magnetization pattern, so its magnetic strength is evenly distributed across the surface. The thicker the material, the greater the strength.

Permanent magnetism is guaranteed as long as the material is not subjected to a demagnetizing force or magnets with stronger magnetic forces.

As a whole, 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: Magnetizers, Magnetic Labels & Magnetic Paper

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

Magnetizers

Magnetizers are used to allure substrates that are packed and or published unmagnetized. There are artificial magnetizers necessary for material used in high-quality marketable printers and handheld magnetizers for use with any size up to 30 mils thick.

Magnetic Labels

A wide range of magnetic labels can be conveniently attached and removed from colorful, magnetically open shells. Magnetic markers also come with different options, including pre-cut and C-channel cardholders, write-on or wipe-off labels, pusillanimous labels, inkjet-printable magnets, and document pockets.

Operations for magnetic labels include:

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

Magnetic Paper

Magnetic paper is a combination of paper and rubber that has been magnetized, and it usually comes in letter-sized (A4) sheets for easy printing. Magnetic paper is popular for short-term advertising and marketing efforts, educational tools, instant magnet prints for fridges, business cards, and so much more. Magnet paper, as the name suggests, is a type of laminate that combines magnetic sheets with paper. It can be cheaply acquired and printed for a wide range of uses.

The magnet paper becomes magnetized due to the elastic rubber or plastic on the reverse, which is embedded with magnetized strontium ferrite powder or another magnetized material. Essentially, thousands of small magnets produce a flexible magnet sheet. The thickness of a magnet designates its strength; however, magnet paper types that are thicker are more limited in terms of the printers that can cope with their size. These types of sheets work best when attached to a solid object, such as a metal surface or a refrigerator door. The material is pliable and easy to cut with scissors. Many different magnets can be produced, such as personalized name tags, without purchasing them in bulk from a traditional custom magnet manufacturer.

Magnet paper can be glossy or matte dull, and the paper is ideal for prints of high quality. The paper can be used on most printers with a single sheet at a time, and the width of the paper usually ranges from 0.6 to 2.4 inches (15 to 60mm). While most companies sell these magnetic papers the same size as normal printer paper, there are other forms, such as larger rolls used for large-format printing. To produce excellent results for magnet printing, the printing process must be done at the topmost quality.

Disadvantages of Magnet Paper

While magnetic paper is a useful product that can lead to some excellent merchandise, some drawbacks also need to be considered. Because of the involved materials in magnet paper, it is considered unsafe for use in laser printers. Inkjet printers are fairly common, but some aged models still induce a good amount of heat, and they may not be right to use for printing on this material. It could also cause deformations in the image being printed, and once the magnet paper is printed, it should not have contact or exposure to excess ultraviolet radiation. Although the material does not rust, its exposure to ultraviolet light can make it very brittle, which could affect its magnetic properties.

Flexible Magnet Products

Flexible magnets have a wide range of products, and a number of them are listed below.

Standard Energy Magnet Strip

The standard energy magnet strip product is generally available in rolls or as individual units. They are durable energy magnet strips used for indoor and outdoor operations and can also be fabricated to different orientations. The adhesive, upon request, can also be laminated, customized, and magnetized. Usually, thickness drives the strength of flexible magnets so that thickness is equated with stronger magnetic strength. Some of the most common uses of magnet strips are package closures, toys and games, displays, arts and crafts, window and door seals, and labeling.

High-Energy Flexible Magnet Strip

High-energy flexible magnet strips are generally used for systems that require maximum strength and stability. The high-energy flexible magnet strips are offered in various standard and custom-made sizes and shapes. In addition, they are available in various energy orientations, making the high-strength magnets extremely resistant to demagnetization, cracking, and dicing.

They can be magnetized through the thickness of the material in a very wide range of configurations. The uses of high energy flexible magnet strips include door latches, trades and crafts, sensors, and magnetic assemblies.

Standard Flexible Magnetic Sheet

The standard flexible magnetic sheet generally uses a multi-pole magnetization pattern. This pattern is for maximum holding power, about 144 pounds (65 kg) per square foot. The standard grade materials are much stronger on one side and can have vinyl and adhesives applied to the weak side. However, it’s possible to custom order double magnetization, giving both sides the same pull strength. The sheets can be cut or die-cut to nearly any required shape or size. There is also a wide range of custom-made and standard colors, thicknesses, and adhesives of standard flexible magnet sheets. Standard flexible magnetic sheets are used for signage, arts and craft, marketing symbols, and display boards.

Printable Wide-Format Magnet Sheet

Printable wide-format magnetic sheets are available to different extents but generally range from 40 to 60 inches (101.6 to 152.4 cm), making them perfect for wide-format print media operations. Laminate options include matte white leak-proof PVC, white dry erase, and other substrates upon request. An all-purpose tempera glue can also be added. Printable wide format magnet sheets have frequent use in operations such as large format and interchangeable graphics billboards, magnet wall systems, control charts, and printed premiums.

Recyclable Print Magnet Sheet

Recyclable print magnet sheets are fabricated by applying a durable printable coating directly to the sheet, making them 100% recyclable and excluding the need for a laminated printing surface. This prevents elimination issues and facilitates easier, cleaner slices due to the absence of an adhesive. Recyclable print magnet sheets are available in standard and custom-made configurations and roll sizes. Recyclable print magnet sheets can be used in indoor and outdoor displays, menu boards, exchangeable graphics, and vehicle signs.

Chapter 3: Types of Flexible Magnets

The different types of flexible magnets include:

Magnetic Sheets or Rolls

A magnetic sheet is a type of printable sheet used for banners, displays, car signs, and art projects. Thin ones are mainly used for crafts like bookmarks and ref magnets. The magnetic sheets are calendared strontium ferrite magnetic cosmetics within a thermoplastic binder to generate a thin sheet, which then magnetizes multiple poles on one face.

A flexible magnetic sheet can attract and hold onto magnetically open faces. It has one magnetic face and can magnetically attract against itself, but it's commonly put against a ferromagnetic layer (mild steel sheet, ferrous sheets, etc.). The binder is the limiting factor on the maximum operating temperature of the magnetic sheets. Above 176 °F (80 °C), the binder starts to soften the magnetic areas to cancel themselves out, which results in demagnetization.

Performance and Variations of Magnetic Sheets

Flexible magnetic sheets come in different forms and finishes. Plain flexible magnetic sheets don’t consist of any vinyl or adhesive shells. They are mostly used by printing companies who desire to add their own vinyl or adhesives by the conversion to meet their specific requirements or needs. Flexible magnetic sheets that are adhesive-backed have a standard acrylic adhesive backing sheet or layer added to the unmagnetized face.

This kind of adhesive-backed flexible magnetic sheet can be stuck to other materials or faces as necessary, for example, in making lightweight magnetic parts. Vinyl-backed flexible magnetic sheets consist of a vinyl layer added to the unmagnetized face. They can also have the vinyl printed onto them to create customized signage, advertising operations, and vehicle signage. The applications of flexible magnetic sheets are in signage, banners, magnetic conversions, magnetic advertising, and magnetic displays like charts.

A magnetic sheet or roll is a permanently magnetized, rubber-based material that is synthetic and has many applications and uses in the signage and graphics sector.

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 stick well to ferrous metallic layers and surfaces, such as metal office cabinets, steel shelving, and metal whiteboards. They can be cut effortlessly with a guillotine or scissors and are compatible with inkjet and laser printers.

The printers are operated by simply placing the magnetic printable paper inside the inkjet printer or laser printer and producing any needed magnetic sign. Magnetic printing paper and sheets are excellent for creating magnetic images and signs for home or plant use; for example, they can produce magnetic prints or organizers for the fridge at home. In the office, they are used for printing business cards, magnetic labels and barcodes, or bills.

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 are high-intensity lines of magnetic polarity that fully cover one surface of the flexible magnetic material. Optimum magnetic strength is found on the inside part of the roll. They are available in many forms as standard or high-energy strips. There are various patterns fit for any exercise, magnetized or not magnetized.

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 is magnetic on one face and consists of distinctive self-adhesive characteristics on the other face.

It is often used in the merchandising, retail, and exhibition sectors to display bills, photos, signs, and other point-of-trade particulars. It is also excellent for creating magnetic closures on products that are printed. All magnetic tapes are supplied in polarity ‘A’ and polarity ‘B.’ If two tapes are being attracted together, there must be an equal amount of each polarity.

A variety of self-adhesive flexible ferrous and steel tapes are used to create a surface that magnetic tape will attract to. Tests are recommended for larger designs since the surface condition has a great effect on the performance of the adhesive.

The surface must be dry, clean, and free of dust. For accurate results, the surface should be cleaned with an appropriate cleaning agent and fully dried prior to use. The adhesive will only cleave completely if it makes full contact with the surface. Rough or uneven surfaces should be avoided. The protective film should be removed just before use, and the adhesive side must not be touched after removing the film.

Some of the shells that have proved suitable for self-adhesive neodymium attractions are listed below:

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

Pressing and Drying the Adhesive

Once the product is in place, pressure has to be applied with a weight along the entire length so that the two shells bond together. Later on, the glue has to be dried for about 72 hours in order to achieve adequate adhesive performance. At this point, pressure can be lifted from the glue.

The optimum temperature for drying is between 69.8 °F and 100.4 °F (21°C and 38 °C). The glue is negatively affected by high temperatures beyond 176 °F (80 °C). Even with the right operation, ultraviolet radiation and humidity can affect the glue's adhesiveness over time.

Before starting work on any design, it should be kept in mind that the glue on adhesive products has a limited lifetime. The lifetimes of some of the adhesive magnets are as follows:

• 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 is only intended as a guideline; the true lifetime of bonds depends on a number of factors such as the surface type, exposure to the sun, humidity, etc. The glue can last much longer under optimum conditions.

Characteristics of Self-adhesive Magnets

High-quality backing that provides great and maximum adhesion Excellent holding capacity Fast release tab for quick, effective removal of the liner Strong neodymium material composition

Attracting Ferromagnetic Surfaces with Self-adhesive Magnets

Adhesive-backed disc magnets of neodymium are used when magnets are needed to attract a ferromagnetic face like steel. The magnets can sometimes be slightly apart but close enough to attract each other. The use of alternate norths and souths, which can boost the magnets’ overall performance, should be considered. This is because the magnets interact positively, pulling and attracting the fields around one another.

Neodymium magnets have magnetic properties, and they repel or attract each other depending on how the magnets are arranged relative to each other. For attraction to occur, there needs to be a north pole facing a south pole on the other magnet (using the magnetic rule of like poles repel and vice versa). So if a north faces a north pole or a south face is directed towards a south pole, the magnets will be repelled from each other.

Understanding how the magnets have to be arranged in the final assembly has an effect on the polarity that is needed for the magnets. Self-adhesive backed disc magnets are mostly used for printing, packaging, arts and crafts, and folder closure sectors. They are also used at home in much simpler uses, such as door catches.

Chapter 4: Applications and Uses of Flexible Magnets

This chapter will discuss the applications and uses of flexible magnets.

Applications of Flexible Magnets

The applications of flexible magnets include:

Garage & Motor Repairs

Magnetic tools are used extensively for the main purpose of saving time and stress for jobs with vehicular problems, garage bays, and servicing in similar operations as given 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 magnetic types are applied in a wide range of display operations to ease application and create minimal damage when removed.

• 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 are occasionally the answer for affordable, quick options for the following:

• 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

The manipulation of adhesive magnets allows for design inventions and excellent manufacturing procedures not possible with brittle or rigid materials. Flexible magnet products can be twisted, slit, bent, coiled, punched, and machined into any shape needed without losing the magnetic energy. Bending produces ring magnets, which are used for small direct current motors. They are easy to machine with standard 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.