The Components of a Silicon Carbide Grinding Wheel

A grinding wheel comprises two major elements – the abrasive grains which cut work material, and its bond which holds them securely together. When dulled abrasive grains become dulled or worn down, their bond breaks apart, exposing new cutting points while maintaining a consistent cut rate.

Weiler offers wheels designed to minimize iron, sulfur and chlorine contaminants for improved workpiece grinding results in stainless steel and aluminum workpieces.

Hardness

Hardness of Abrasives in Grinding Wheels Determines their Cutting Capabilities Typically, harder grains provide more aggressive cuts. Bond Hardness Also Impacts Performance Hard bonds keep abrasive grains together better against grinding forces than soft bonds which permit easier breaking.

Hard abrasives like black silicon carbide feature sharp, brittle grains that cut quickly. It is best suited for grinding non-ferrous metal workpieces. On the other hand, softer abrasives such as brown fused alumina feature weaker, more rounded grains which make them suitable for grinding cast iron and aluminum workpieces.

Softer grinding wheels feature lower grind rates and are suitable for grinding all materials, including steels and stainless steels. A harder wheel boasts greater grinding action, making it more suitable for tougher, harder materials such as cast iron. When choosing the appropriate wheel grade and concentration, take into account factors like workpiece type, material removal rates, machine horsepower available and coolant used as guides.

Bond

A grinding wheel’s bond holds together its abrasive grains. Its hard or soft nature determines its longevity and performance – with harder wheels tending to last longer while soft bonds may expose new grains faster and provide superior cutting abilities.

Abrasives used in wheels are also key, as different grains offer unique advantages depending on the material being processed. Aluminum oxide works particularly well for metals like steel and iron; however, its lack of cut rate or longevity limits its use as an abrasive.

Black and green silicon carbide abrasives are popular choices of abrasives for cutting nonmetallic materials with low tensile strength, like glass, ceramics and refractory materials. Green silicon carbide may cost more but is ideal for use on hard, brittle materials like titanium alloy or optical glass.

Pores

A grinding wheel’s performance depends on its pore size. A larger pore size enables greater abrasive loads to be applied, enabling deeper penetration of its grains into material being ground resulting in greater removal in small chips.

Pores play an integral part in the sintering process and contribute to the porous nature of sintered silicon carbide bodies. While it is possible to control porosity with variations in time/temperature profile settings, this method often fails to deliver reproducible structures with uniform distribution of pore sizes.

The present invention provides a method for producing porous silicon carbide-based materials with high tap density, providing ideal conditions for use such as excellent oxidation resistance, acid resistance, particulate matter reaction resistance and thermal shock resistance. This invention employs organic pore formers in sufficient quantity that they won’t burn off during firing or decompose into dust during processing.

Grade

Hard and soft grades refer to the relative strength of the bond that holds together the abrasive grains in a grinding wheel. Hard grades indicate strong bonds that resist grinding forces that try to pry loose the grains; soft grades have weaker bonds which release more easily, providing faster cutting ability while prolonging wheel life.

Considerations should be given when choosing a grinding wheel depending on the material being ground and desired finish. Hard brittle materials tend to work best with finer grit sizes and soft-graded wheels while for more flexible materials medium to coarse grit sizes and softer bonds are better suited.

Aluminum oxide (white fused alumina) is an ideal abrasive choice for steel and iron surfaces, though its cut rate quickly dulls with use. Cubic boron nitride (CBN) works better on harder to machine steels while diamond can handle harder materials more effectively.