Grinding media typically includes any material placed inside a rolling mill. As these media spin around inside the mill, they have a number of desired effects on the objects or materials inside the mill. Various grinding media each accomplish their own desired effects. The following examples will show you how various media work.
These are literally small rocks thrown into the mill. They are imperfect in shape, but most are of the same size. The purpose of flint pebbles is to pulverize with repeated stone beatings as the mill spins. They are most effective for pulverizing equally as hard objects or softer materials.
Sand in a rolling mill is akin to lining the machine with sandpaper. The sand softens objects, making them smooth and blemish-free. It is the fastest way to smooth everything from wood to stone.
Nylon balls are very soft, almost rubbery, but do not let that fool you. When nylon balls are placed inside a milling machine that is spinning at tens of miles per hour, or "x" number of rotations per minute, these balls become blasting projectiles against soft materials and soft objects. Fine-grain particles of the materials are one such result.
Soda Lime Glass Balls
If you have ever played with a slingshot, or used a slingshot for hunting small game, then you are already familiar with soda lime glass balls. Even though these balls are made of glass, they quickly become powerful projectiles. They can punch holes in wood and dent metal in ways you can only imagine, until you have seen the final product come out of the milling machines.
Steel Balls ("Steelies")
Steel balls are the go-to grinding media when milling companies want to really pulverize and nearly obliterate a material or object. Often referred to as "steelies," these carbon steel balls have also been used in kids' games and activities because they hold up a really long time. If a miller wants grinding media that outlasts most others, the steel balls are the way to go. They also hold up under extreme heat, extreme cold, and intense friction.
A lot of grinding media is either granular or spherical in form. Cylinders, on the other hand, are an entirely different product. They look exactly as they sound; sort of cylindrical. Their effect is two-fold; pound through, roll smooth. They may not be used as often, but they are ideal for jobs that require less smashing and more finesse.
Contact a company like STR Industries to learn more.