The so-called wheel hardness is above abrasive grinding wheel grinding job shedding in the degree of difficulty, we are generally referred to as the wheel hard and soft, suitable for different grinding wheel hardness different workpieces, if wheel too hard, blunt the the abrasive is not timely shedding, will generate a lot of heat, burn the workpiece; if the wheel is too soft, then make the abrasive off too fast and not fully effective.
1, the greater the contact surface grinding wheel and the workpiece, choose softer wheel, on the contrary, on the choice of high hardness grinding wheel;
2, the harder workpiece, the softer selected wheel, the softer parts, the harder the selected wheel;
3, grinding and profile grinding wheel should choose harder to maintain the necessary wheel shape accuracy;
4, the cooling liquid than dry grinding the  grinding wheel  hardness grade 1 to 2 hours;
5, the larger the particle size of the wheel, in order to avoid debris blocked by grinding wheel, generally softer wheel to choose;
6, in the same grinding conditions, with resin bonded grinding wheel vitrified wheel than the hardness of 1-2 small higher grade;
7, end mill compared with the circumference of the grinding should choose something softer wheel;
8, wheel rotation speed is high, the hardness of the optional soft wheel 1 to 2 small magnitude.
9, the grinding of the workpiece poor thermal conductivity should be selected softer wheel;
10, grinding soft and toughness of non-ferrous metals, the hardness to be elected was softer.

  Is a superhard abrasive grains, pores, formed by combining together the three binders. Visible, with abrasive agent is an indispensable part of production, its role is to bond abrasive grains having a given geometry and to hold on to in the processing of abrasive grinding force to withstand the cutting action and play. Superhard abrasive binders three major categories: resin bond, vitrified bond, metal bond. How to choose the right combination of agents, mainly based on their own performance and processing on the abrasive requirements. Resin bond. Which itself has good flexibility and a polished, the formation of abrasive, still has a good self-sharpening, easy to plug, trimming less, and high grinding efficiency, low grinding temperature, grinding surface finish, So wide range of applications. Combined with the formation of diamond abrasive resin bond diamond abrasive, often used in cemented carbide parts, steel-based alloy parts, as well as some non-metallic materials, semi-fine grinding, fine grinding, etc.; combined with a resin binder to form a resin binder CBN abrasive, mainly for high vanadium high speed steel cutting tools and tool sharpening steel, tool steel, stainless steel and heat-resistant alloys workpiece half grinding, fine grinding. However, resin-bonded abrasive gripping of the poor heat resistance is poor, leading to high abrasive wear of the grinding large, especially at high load, especially when grinding, often plated with a metal jacket to be abrasive improved. Vitrified. Such binders for abrasive bonding strength than resin. After the formation of grinding, the chip performance and the working surface, so that clogging, sharp cutting, grinding efficiency, and a small amount of thermal expansion is easy to control the machining precision, these features are beneficial to the grinding process smoothly. In abrasive shaping and trimming, the operation is relatively easy, generally used for roughing, semi-grinding, as well as a large contact surface of the molding grinding, etc., so the ceramic binder is used widely as a binding agent. Vitrified bond diamond abrasive combined with better stability when in vitrified CBN  grinding wheel areas have good market and reputation. Vitrified bond diamond abrasive when combined with the difficulty coefficient is relatively large, vitrified bond diamond wheel development has been hampered. Bronze metal binding agents are binding agents and binding agents plating two categories. Plating binding agent is a binding agent with a higher strength, generally a single layer or multi-grain plated by electroplating on the metal base, the kind of binding agent on the work surface abrasive grain number per unit area than the other several kind of binding agent is much higher, and are exposed abrasive surface of the binding agent, and thus sharp cutting, grinding efficiency. But by the thickness of the coating limits the total abrasive life is not high, generally used for special purpose processing, such as form grinding with abrasive, a small lap, nesting knives, electroplating reamers, files and so on. As technology continues to progress, CBN electroplated metal bonded abrasives in the expanding applications, particularly in the processing of various types of steel parts of the holes, the cavity will become more prominent, not only high grinding efficiency, economy good, but also to obtain a better shape precision. Is a bronze bond abrasive powder, tin powder as the main material and other supplementary materials to improve its performance thoroughly mixed, then the mixed abrasive added thereto, and then placed in a mold press forming and sintering. The combination of this kind of abrasive agents and abrasive combination of high strength, wear resistance, wear, so long life, but also to maintain a good shape, it can withstand a greater load. But the drawback is poor since the grind, the surface is easy to plug, heat a large, trim is also very difficult. Mainly used for glass, ceramics, stone, building materials, concrete, metallic materials, semiconductor materials such as coarse grinding, fine grinding and cutting step, a small amount for carbide composite superhard materials grinding and profile grinding and various honing, electrolytic grinding and so on.