For successful machining, you need well-maintained, very sharp cutting tools that will ensure speed and precision. How sharp you’re able to keep those tools depends on the type of grinding wheel you have and the method of grinding you use. Grinding wheels and their abrasives are classified as either conventional wheels, which are usually made from aluminum oxide, or CBN (cubic boron nitride) wheels. CBN is a synthetic material that has many of the same properties as diamond; it’s used for industrial applications such as cutting and grinding.
Why Use a CBN Grinding Wheel
Traditional grinding wheels will overheat and wear down more quickly than diamond or CBN wheels. Conventional wheels can wear out and dull faster than CBN wheels, and using an inferior abrasive to grind the super-hardened steel found in most machine shops can damage the steel. When overused, conventional wheels are also more likely to produce issues with the workpiece, such as thermal damage and a poor finish.
CBN wheel grinding, therefore, is the best method to sharpen worn-out tools and restore them to tip-top condition. If properly cared for, a CBN wheel will last much longer because it’s more durable and has higher material removal rates; in fact, CBN wheels are twice as hard as aluminum oxide abrasives. This strength and durability result from the bonding between the steel hub and the grains.
CBN wheels are well-suited for high-speed grinding of superalloy steel tools because of their higher abrasive resistance and higher thermal conductivity. The cooler cutting action reduces thermal damage at the cutting edge. You need apply only a small amount of pressure to sharpen tools on a CBN wheel, as the grind is very fine—this keeps tools sharp and precise.
Cost Benefits
New automation and flexibility developments in tool-grinding machines have increased precision and productivity. The use of CBN wheels to grind milling cutters, end mills, and a variety of other hardened cutting tools can reduce the overall cost of grinding by extending the life of the tools. Plus, CBN wheels can be used dry and without coolant, keeping overhead costs down. More precise grinding will also reduce the amount of material taken while sharpening and producing better cutting edges. Because CBN wheels last longer and require little to no conditioning, less maintenance is needed. The overall savings, depending on the applications, can range from 20-50% over conventional wheels.
