What are the benefits of plated vs. bonded?
Grinding Wheels 101
A grinding wheel performs a range of abrasive machining operations in industries such as aerospace and petroleum. It can be made by pressing a matrix of coarse particles together into a circular shape, or by coating a solid material with the abrasive compound. The specific materials and shape of a grinding wheel depend on the application, although its manufacture is generally a precise process. Common types of grinding wheels include plated wheels, wheels that use resin to bond the abrasive compound to the wheel and those that use metal bonds.
A plated grinding wheel has a single layer of abrasive material that’s exposed to the surface, instead of embedding the material within a bonding compound. The abrasive material for this type of grinding wheel is typically cubic boron nitride (CBN) or diamond, which are extremely hard substances. Diamond plated wheels hold their form longer than bonded wheels, and they also form a more aggressive bond.
Electroplating provides diamond tool manufacturers with the ability to strip the abrasive material from the core product and re-plate it with a new abrasive layer. This advantage results in a plated diamond wheel that’s in “like new” condition, which extends the life of the initial investment.
The resins that bond abrasives to grinding wheels are typically phenolic resins, meaning that they are made by reacting phenol. The resin also contains filler materials such as copper and an abrasive material like diamond or CBN. A hot press compresses this mixture into the desired form, which is then cured and machined to a precise shape.
Resin-bonded grinding wheels are highly efficient, allowing them to complete their tasks quickly. These grinding wheels are capable of prolonged use, due to their ability to sharpen themselves and maintain low temperatures during operation. Grinding wheels that use resin bonds are also easy to dress and less prone to overloading. Common applications for these wheels include grinding electrical carbon products such as carbide alloys, ceramics, ferrite and semi-conductors.
The metal bonds used by grinding wheels are typically made by sintering powdered metals along with filler materials, and adding an abrasive such as CBN or diamond. These bonds are very strong, providing a grinding wheel that holds its shape well. The durability of metal bonds also means that these grinding wheels require dressing less frequently.
Metal bond abrasive tools offer maximum productivity, and are suitable for a range of applications, from light polishing to aggressive grinding. They’re most often used in wet grinding, but they can also grind dry surfaces such as ceramics, glass, quartz and silicon. Metal-bonded grinding wheels can be used for cutting tools and forms such as refractories. They're also suitable for creep-feed applications.