如何选择合适的碳化硅砂轮

Grinding wheel abrasive grains must be sharp and durable to be effective cutting tools, with their strength determined by a bond which holds them together.

Aluminum oxide wheels with hard bonds provide long lifespans and fast cuts on materials like aluminum, brass and soft bronze. Zirconia alumina blends provide even faster speeds and higher durability for rough sanding applications.

Abrasive Grit

Abrasive grind is one of the cornerstones of any grinding wheel, offering various abrasive grains designed specifically to meet specific applications and operating conditions.

Emery is one of the most frequently used natural abrasive grains, followed by garnet, aluminum oxide and zirconia alumina. Each has different properties for hardness, strength and fracture toughness – each size determines which grids will appear on a grinding wheel as quickly as it will cut.

Silicon carbide is an extremely hard synthetic abrasive with sharp, friable grains that fracture to expose new cutting edges, which allows it to cut more quickly than aluminum oxide and is an ideal choice for metals, rough materials and wood refinishing projects. Also used as an intermediate step between coats of finish in woodworking projects. Available on belts, sheets disks or sponges it provides consistent high quality cuts throughout its life span while remaining more expensive than its aluminum oxide counterparts.

邦德

Bond types determine how well abrasive particles are held together. Furthermore, this affects how much pressure is applied during grinding; harder bonds may extend the wheel’s lifespan but reduce sharpness and slow cut rate while softer bonds allow faster stock removal by disintegrating more quickly to expose more abrasive grains more frequently.

Aluminum oxide wheels are best used for grinding low-tensile steels and ferritic cast irons, providing good durability and finish while being less effective at cutting hard metals than CBN or diamond wheels. For this task, CBN or diamond wheels may be more appropriate.

Green-silicate bonds (GC) of these wheels are made by mixing potassium silicate powder and Florida kaolin into a dry mix, pressing the blank, drying, and roasting until a porous body emerges that won’t glaze at high wheel surface speeds. Their abrasive grains are less sharp than in black-silicate bonds; hence these wheels can be used for processing glass, ceramics, nonferrous materials and alloys.

Grade

A grinding wheel grade determines how tightly its bond holds abrasive grains together and also influences both how quickly abrasives are cut away and its surface finish.

Abrasive grains cut into the workpiece surface to remove material in small chips, wearing away at their cutting points as they work, leaving new cutting points exposed in their place. Over time, friction between workpiece and abrasive causes heat build-up; eventually it causes fractured grains with fresh cutting points exposed on them.

Selecting an appropriate grade for your application depends on both the material being worked with and its hardness. In general, hard and potentially brittle materials require finer grit sizes with softer grades to avoid overworking the abrasive grains; soft and ductile materials may benefit more from medium to coarse grit wheels.

Pores

Porous grinding wheels allow coolant to flow freely and regulate heat production, keeping abrasives sharp while controlling temperatures. If the pores of a wheel are not large enough to release coolant efficiently, however, it could clog and become ineffective over time.

Bonds must also hold together and provide sufficient spacing between abrasive grains. Without sufficient porosity and spacing, the abrasive can wear away prematurely and become filled with chips, becoming ineffective and becoming clogged up with debris.

Low temperature vitrified bond specially developed to minimize its chemical reactivity with silicon carbide has been combined with hollow ceramic spheres for producing highly effective abrasive wheels suitable for grinding titanium and soft materials found in precision metal working parts, such as composite composites. These wheels offer outstanding grinding results.

Green silicon carbide outshines black silicon carbide when it comes to grinding hard and brittle materials such as tungsten carbide, optical glass and ceramics. Pink fused alumina is ideal for workpieces that demand high surface quality such as tools, instruments threads or threaded workpieces.