Cutting discs are tools for grinding, grinding and polishing. Most of the cutting discs are artificial cutting discs made of the abrasive plus binder, and natural cutting discs directly processed from the natural mineral rock. In addition to being widely used in machinery manufacturing and other metal processing industries, cutting discs are also used in the processing of food processing, the paper industry, and non-metallic materials such as ceramics, glass, stone, plastics, rubber, and wood.
During the use of the cutting disc, when the abrasive grains are blunt, the abrasive grains are partially or completely detached from the cutting disc due to partial fragmentation of the abrasive grains or breakage of the bonding agent, and the abrasives on the working surface of the cutting disc are constantly emerging. The cutting edge, or constantly revealing new sharp abrasive particles, allows the China cutting disc for metal to maintain cutting performance for a certain period of time. This self-sharpness of the cutting disc is a prominent feature of the cutting disc compared to the general tool.
As early as the Neolithic Age, humans began to use natural grinding stones to process tools such as stone knives, stone axes, bones, horns, and teeth. In 1872, in the United States, natural abrasives and clay were combined. Ceramic grinding wheel; around 1900, artificial abrasives were introduced, and various cutting discs made of artificial abrasives were successively produced, which created conditions for the rapid development of grinding and grinding machines. Thereafter, the proportion of the natural cutting disc in the cutting disc is gradually reduced.
The cutting disc is divided into two types according to its raw material source: natural cutting disc and artificial cutting disc. The natural cutting disc commonly used in the machinery industry is only oil stone. The artificial cutting discs are distinguished according to the basic shape and structural features, and there are five types of grinding wheels, grinding heads, oil stones, and tiles (collectively referred to as consolidated cutting disks) and coated cutting disks. In addition, it is customary to classify abrasives as a type of cutting disc.
Consolidated cutting discs can be divided into ordinary abrasive consolidation cutting discs and super-hard abrasive consolidation cutting discs according to the abrasive used. The former uses ordinary abrasives such as corundum and silicon carbide, and the latter is made of superabrasives such as diamond and cubic boron nitride. In addition, there are some special varieties, such as sintered corundum cutting discs.
Ordinary abrasive consolidation cutting disc is a cutting disc which is fixed into a certain shape by a bonding agent and has a certain strength. Generally composed of abrasives, binders, and pores, these three parts are often referred to as the three elements of a consolidated cutting disc.
The abrasive acts as a cutting in the cutting disc. Bonding agents are materials that consolidate loose abrasives into cutting discs, both inorganic and organic. Inorganic binders include ceramics, rhombohedral and sodium silicate; organic resins, rubber, and shellac. The most commonly used are ceramic, resin and rubber binders.
The pores act as chipping and chip removal on the grinding debris during grinding and can accommodate the coolant to help dissipate the heat. In order to meet certain special processing requirements, some fillers such as sulfur and paraffin may be impregnated in the pores to improve the performance of the cutting disc. This filler, also known as the fourth element of the cutting disc.
Items that represent the characteristics of a conventional abrasive-consolidated cutting disc are shape, size abrasive, particle size, hardness, texture, and bonding agent. The hardness of the cutting disc refers to the difficulty of the abrasive particles falling off the surface of the cutting disc under the action of external force, which reflects the strength of the abrasive particles held by the bonding agent.
The hardness of the cutting disc mainly depends on the amount of the bonding agent added and the density of the cutting disc. The easy rubbing of the abrasive grains indicates that the hardness of the cutting disc is low; otherwise, the hardness is high. The hardness grades are generally divided into seven levels: super soft, soft, medium soft, medium, medium hard, hard and super hard. From these levels, several small levels can be subdivided. The method for determining the hardness of the cutting disc is more commonly used by a hand cone method, a mechanical cone method, a Rockwell hardness tester method, and a sandblast hardness tester.
The hardness of the cutting disk has a corresponding relationship with its dynamic elastic modulus, which is advantageous for determining the hardness of the cutting disk by the dynamic method of measuring the dynamic elastic modulus of the cutting disk. In the grinding process, if the material of the workpiece to be ground is high in hardness, a cutting disc with a low hardness is generally used; otherwise, a cutting disc having a high hardness is used.
The cutting disc tissue is roughly classified into three types: compact, medium and loose. Each class can be subdivided, etc., and is distinguished by the organization number. The larger the disc number of the cutting disc, the smaller the volume fraction of the abrasive in the cutting disc, and the wider the gap between the abrasive grains, indicating that the tissue is looser. Conversely, a smaller organization number indicates a tighter organization. The cutting disc of the looser structure is not easy to passivate when used, and the heat is less during the grinding process, which can reduce the heat deformation and burn of the workpiece. The tightly-disposed cutting disc abrasive grains are not easily peeled off, which is advantageous for maintaining the geometry of the cutting disc. The organization of the cutting disc is controlled only by the cutting disc formulation at the time of manufacture and is generally not measured.
The super-hard abrasive consolidated cutting disc is mainly a cutting disc which is consolidated with a bonding agent such as diamond or cubic boron nitride. Due to the high price of a diamond and cubic boron nitride and good wear resistance, the consolidated cutting discs made of them are different from the ordinary abrasive-consolidated cutting discs, in addition to the super-hard abrasive layer, there are transition layers and substrates.
The super abrasive layer is part of the cutting action and consists of a superabrasive and a binder. The matrix is supported by grinding and consists of materials such as metal, bakelite or ceramic. The transition layer is used to join the matrix and the super abrasive layer, consisting of a bonding agent, and sometimes it can be omitted. Commonly used binders are resins, metals, plated metals, and ceramics.
The manufacturing process of the consolidated aluminum flat cutting disc includes: dispensing, mixing, molding, heat treatment, processing, and inspection. The manufacturing process is different depending on the binder. The ceramic bond cutting disc mainly adopts the pressing method and the abrasive and the bonding agent are weighed according to the weight ratio of the formula, and then uniformly mixed in the mixing machine, put into the metal mold, and the cutting disc blank is formed on the press machine. The blank is dried and then calcined in a kiln, and the firing temperature is generally about 1300 °C. When a low melting point fusion bonding agent is used, the firing temperature is lower than 1000 °C. Then accurately process according to the specified size and shape, and finally check the product.
The resin bond cutting disk is generally formed on a press at room temperature and is also subjected to a hot pressing process which is heated while being heated under heating. After molding, it hardens in the hardening furnace. When the phenol resin is used as a binder, the curing temperature is 180 to 200 °C.
The rubber bond cutting disc is mainly mixed with a roller machine, rolled into a thin sheet, and then punched and formed by a punching knife; some is also loosened and put into a metal mold to form on a press. After molding, it is vulcanized in a vulcanization tank at a temperature of 165 to 180 °C.
The metal bond cutting disc is manufactured by powder metallurgy and electroplating and is mainly used for super-hard abrasive consolidation cutting discs. The powder metallurgy method uses bronze or the like as a binder, and after the mixture is mixed, it is formed by hot pressing or under room temperature conditions, and then sintered. The electroplating method uses nickel or nickel-cobalt alloy as the electroplating metal, and the abrasive is fixed on the substrate by an electroplating process to form a cutting disc.
Special varieties of cutting discs include sintered corundum cutting discs and fiber cutting discs. The sintered corundum cutting disc is made by mixing and molding aluminum oxide powder and an appropriate amount of chromium oxide, and sintering at about 1800 ° C. The cutting disc has a compact structure and high strength and is mainly used for processing parts such as watches and meters. The fiber cutting disc is made of a fiber yarn (such as nylon yarn) containing or adhered with an abrasive, and has good elasticity, and is mainly used for polishing metal materials and products thereof.