亚洲 视频 导航 一区_91精品丝袜久久久久久_A级黄色毛片视频_亚洲最大成人AV_亚洲人人操av_亚洲无码色色网

Different grinding wheels should be used for different workpiece materials and different processing requirements. Even if grinding the same workpiece material, the grinding ratio of different brands of grinding wheels may differ by 2~5 times, so the appropriate grinding wheel should be selected.

Diamond grinding wheel is the best grinding tool for hard alloy, optical glass, ceramics, gemstones and non-metallic materials with high hardness and high brittleness such as stone. But because diamond is easy to be carbonized at 700℃~800℃, it is not suitable for grinding steel. CBN slightly inferior to the hardness of diamond, but its thermal stability (which can withstand temperatures up to 1300 ℃ ~ 1400 ℃), it is not like a diamond in the high temperature decomposition, namely, oxidation and graphitization, and iron element chemical inertness, high thermal conductivity (46 times that of corundum), made of the grinding wheel long life (up to several dozen times the corundum grinding wheel to into more than one hundred times), is the alternative corundum grinding wheel grinding of hardened steel, high-speed tool steel, bearing steel, stainless steel, heat-resistant steel and titanium alloys such as the best abrasive hardness toughness of metal materials.

The bonding agent of super hard abrasive wheel is resin, metal, ceramics, electroplating and brazing. Resin bonded grinding wheel is mainly used for cutting tool measuring tool, grinding hole, cylindrical grinding and plane grinding. The metal bonded grinding wheel is used for cutting into the shape grinding of optical curved line grinding machines, grinding single edge cutting tools, grinding spiral groove of small bit, and also suitable for electrolytic grinding; Ceramic binder grinding wheel of high grinding efficiency, good shape retention, high durability, easy dressing, grinding wheel service life is long, and because of ceramic bond itself has good chemical stability, heat resistant, oil resistant, resistant to acid and alkali erosion, can adapt to all kinds of grinding fluid, grinding cost is low, and therefore has to make the first selection of high efficiency, high precision grinding abrasive; Electroplated grinding wheels are suitable for high speed fine grinding and forming grinding, as well as for efficient grinding of holes (wet grinding) and for use on coordinate grinders; Brazing wheel is suitable for ultra-high speed grinding.

It must be pointed out that abrasive of different brands has different crystal shape and particle shape due to different manufacturing processes, and has different strength, thermal stability and crushing characteristics. Different abrasive materials should be selected according to the type of binder, the material of grinding work piece and grinding method. For high-strength, high-precision grinding of ceramic bonded wheels, use abrasive materials with sharp grain shapes such as PDA (synthetic diamond) and ABN800 (CBN) manufactured by DeBeers or other similar brands.

There are two kinds of metal-plated coating (metal coating can strengthen and toughen, reduce thermal impact, and act as a bonding bridge between abrasive particles and binder, which can improve the performance of grinding wheel) and non-metal-plated coating, which should be selected according to different conditions such as binder type, workpiece material, dry grinding and wet grinding, etc. Copper clothes are generally used for dry grinding, such as RVD-Cu and CBN-Cu. Wet grinding choose nickel clothing, such as RVD-Ni, CBN-Ni. At present, the plating metal has developed from nickel, copper to titanium, tungsten alloy, nonmetallic ceramics, from single coating to composite coating, and has developed from abrasive coating to micro powder coating.

The concentration of hard abrasive grinding wheel should not be too low. High concentration can lead to a high grinding ratio. The 200% concentration of super hard abrasive wheel is actually a kind of ordinary grinding wheel with super hard abrasive as auxiliary material, so it is generally not recommended to use it in naming. Before the eyes, high concentration of high speed and high efficiency grinding is used, high concentration of ceramic binder CBN grinding wheel is used, the concentration of ceramic binder CBN grinding wheel is generally selected above 125%, such as imported matching ceramic CBN grinding wheel, its concentration is generally 175%~200%.

The hardness grade of the grinding wheel indicates the amount of holding force of the cement on the abrasive. Uniform and stable hardness of grinding wheel and reasonable choice of hardness are important prerequisites to ensure grinding quality. Foreign super hard abrasive grinding wheels generally have 3~7 hardness grades to choose from, but the super hard grinding wheels produced in China are not standard hardness grades, and corresponding standards are not stipulated in GB6409, so the quality is not easy to guarantee, bringing inconvenience to users, and it is urgent to be supplemented and improved.