Wheel dressers and dressing tools are used to condition, true and dress grinding wheels. Dressing is the process of re-sharpening the tiny cutting edges on a grinding wheel’s surface. Diamond tools and wheel dressers fracture the grinding wheel’s abrasive grains in order to produce sharp new edges. This process also cleans out the tiny spaces between the grains, removing metallic dust and other particles that can clog the grinding wheel’s face. Typically, wheel dressers and dressing tools are mounted at a “drag” angle to the grinding wheel so that the cutting point can be turned frequently. This maintains the point’s sharpness and prevents crushing or glazing of the grinding wheel’s face. It also extends the life of the cutting tool. Some wheel dressers and dressing tools are hand-held devices. Others are machine or table-mounted. Important specifications to consider include the outer diameter (OD) of the grinding wheel to be dressed.
There are several types of wheel dressers and dressing tools. Dressing rolls and rotary tools are rugged rolls or wheels that are coated with diamonds for creep fed grinding applications. Dressing spindles are spindle-mounted tools or rolls that often include an integral drive and brake. Dressing sticks are rectangular or block-shaped devices that contain bonded abrasives. Impregnated or grit dressing tools provide a section or layer of diamond or superabrasive grain bonded in a matrix. Single point dressing tools include one diamond or superabrasive point while multi-point or cluster dressing tools position several diamonds or superabrasive points across a dresser surface. Dressing machines hold, position, and move the dressing tool relative to the grinding wheel and usually feature integral drives and braking systems. Huntington dressing tools are made of steel and consist of star-shaped discs or rollers for coarse dressing operations. Radius or profile tools dress a negative profile of the desired part or shape into the grinding wheel. Truing devices, which reduce vibration and produce a wheel with a uniform cutting rate, are used to correct the concentricity and shape of grinding wheels.
Dressing Materials and Abrasives
Wheel dressers and dressing tools use several types of dressing materials and abrasives. Diamond, the superabrasive grain with the highest hardness, is produced synthetically in high temperature, high-pressure anvil presses. Diamond is often used for dressing bonded abrasive wheels as well as for grinding nonferrous metals, ceramics, glass, stone, and building materials. Aluminum oxide, the most common industrial mineral in use today, is fused with bauxite and additives such as titanium to produce ingots that are later crushed and sized. Boron carbide, another very hard abrasive, is used in bonded wheel dressings and loose abrasives that include tungsten carbide or other hard alloys. Typically, tungsten carbide grits are used in metal-bonded products to abrade tough materials such as composites, fiberglass, reinforced plastics, and rubber. Silicon carbide is used to grind non-ferrous materials such as brass, aluminum, and titanium. Steel, an alloy based on iron and carbon, is used in a variety of structural and tooling applications and often contains additives such as chromium, nickel or molybdenum.