HISTORY
The magnet has had a rich history throughout human civilization, from its 500 BC Greek discovery, then British experimentation in the 17th century, to its diverse range of applications around the world today. Its name is derived from ‘Magnesia’ of ancient Greece, where naturally occurring magnets or lodestones were originally unearthed.
By the 13th century, many of the continents had developed magnetic compasses to navigate using the Earth’s own magnetic field. The 21st century has seen its wide application in industries spanning from medical and health, engineering, automotive, electronic, manufacturing–the magnet is a force to be reckoned with!
Magnetic Field and Magnetic Force
Just like Earth, there’s a North pole and South pole on every magnet, points where the magnetic force is strongest. Dissimilar poles in different magnets are attracted to one another, while similar poles repel.
The magnetic field, or magnetic flux density, is measured by the units ‘gauss’ and ‘tesla’ (10, 000 G = 1 T), which increases with magnet thickness. The higher the gauss reading, the stronger the magnet is. View our high-strength anisotropic magnets, whose magnetic properties are set during calendaring.
Magnet pull force is a force that exists between two magnets that are close enough together to enter each other’s magnetic field. This pull force or pull strength is perpendicular to the magnetic field and is measured by how much force is required to separate the two magnets.
Flexible Magnets
Depending on the shape, flexible magnets are made by one of two processes–extrusion or calendaring. Extrusion is used to form profile-extruded shapes that have irregular cross-sections, such as ridged magnetic strips. This process squeezes a heated rubber magnetic compound through a die of the desired shape, producing lines of bubble-free, compact magnets.
In calendaring, rubber or synthetic resin pellets containing magnetic powders are compressed between two rollers to the desired thickness, producing dense and uniform magnet sheeting. 0.015”, 0.020” and 0.030” are go-to thicknesses in the advertising world due to their wide reach–there’s at least one fridge magnet in every household!
Benefits to flexible magnets are wide versatility and their ability to easily mold around most shapes–at 20 degrees Celsius, they can be coiled into a 0.5” radius before cracking. Working with flexible magnets is so easy you can pick up your household scissors since they can be sliced, drilled, punctured, scored, you name it. They are also heat-resistant up to 100 degrees Celsius.
Plain and Simple
Jasdi offers plain magnetic sheeting, which is pure, unadulterated magnetic material. Plain sheets are ideal for printers that have their own equipment and want to affix their own adhesive substrate. come in a wide range of thicknesses and are available in two grades:
Isotropic produced without magnetic orientation
Anisotropic oriented using electromagnetic exposure to achieve higher strength
Vinyl
We have a wide assortment of colour vinyl magnet sheeting to suit your specific needs: black, white, green, blue, red, yellow and orange, in either a matte or gloss finish. Printed vinyl magnets attract attention, enhance your company’s professional feel and elevate your products above the competition. A list of print methods and compatible printer brands can be found under Finishing Techniques.
Self-Adhesive (Peel and Stick)
A popular item is our self-adhesive magnets (pressure-sensitive adhesive), which can easily adhere to any material that has a slightly textured, un-slick surface. This flexible magnet sheeting can be easily used for a variety of signage applications, stationary and craft projects.
Hard Magnets
Hard magnets are commonly used in the electronics, automotive and advertising industries, since they are a cost-effective solution with stable magnetic properties. There are several different hard magnet types that vary by alloy composition and pull force, and the grade of raw magnetic material usually dictates the quality and strength of the magnet. The manufacturing process is complex and highly regulated for quality control and consistency to produce industry standard magnets.
Ceramic magnets, also known as Ferrite magnets, are made of powdered ferrite alloys combined with cobalt, strontium or barium oxides. Their maximum energy product is 3.4. Ferrite magnets undergo intensive heat and pressure during the injection moulding process and are available in discs, rings, blocks and cylinders. They require careful handling due to how brittle they are, since impact with another hard material will produce cracks or chips.
Neodymium-Boron magnets (NdFeB) are currently the most popular rare earth (metallic elements in the rare earth family on the periodic table) magnets commercially available and the least likely to lose magnetism. Their maximum energy product ranges between 35 to 52.
NdFeB magnets are brittle and extremely hard and dense, so even standard industrial grade tools will warp if attempting to drill or machine. Due to their low resistance to corrosion, neodymium magnets are plated, usually with a nickel alloy.
They are also very sensitive to heat, and exposure to temperatures over 80 degrees Celsius will permanently decrease the magnetic strength. The alloy was developed in the 1980’s to alleviate rising raw material costs. Since then it has become an industrial staple due to its impressive magnetic pull force.
*For more technical information, please visit our Technical Data page. |