Structure and Characteristics of Diamond Bit

In machining, diamond grinding wheel, PCD tool and tool, honing oil stone, finishing roller and drawing die are widely used

I. overall structure

The diamond material bit is a one-piece bit. The whole bit has no moving parts, mainly including bit body, crown part, hydraulic structure (including water hole or nozzle, water tank, also known as flow channel, chip chute), diameter protection and cutting edge (tooth). The crown of the diamond bit is the working part of the bit cutting rock. Its surface (working face) is provided with cutting teeth of diamond material and arranged with hydraulic structure. The drill bit body is a steel material body. The upper part is connected to the drill string and the lower part is connected with the crown tire body (the steel crown is integrated with the drill bit body).

The hydraulic structure of diamond bits is divided into two categories.A type of natural diamond drill and TSP drill, in which the drilling fluid flows out of the central water hole and disperses across the surface flume of the bit to cool, clean and lubricate cutting teeth on the bit face.The other type is used for PDC drills, where the drilling fluid flows out of the water hole and is dispersed through various shunt elements to the drill face for cooling, cleaning and lubrication of the cutting teeth.The location and quantity of water holes of PDC bits depend on the structure of the bits.

The diameter protection part of diamond material plays the role of centralizing bit and ensuring that the well diameter is not reduced during drilling.

The cutting teeth of the bit of diamond

Diamond bit cutting teeth materials are divided into natural diamond and artificial diamond.Diamond is the crystal of carbon, whose crystal structure is a tetrahedron. Carbon atoms are linked together by covalent bonds. The structure is very stable.

Diamond is the most hard material, which has the strongest compressive strength and the highest abrasion resistance. Therefore, it is the most ideal material for cutting edge of bit.

However, as the cutting edge material of bit, diamond also has great weakness.First, it is brittle and will break under impact load.Second, it is bad, the thermal stability of diamond under high temperature combustion into carbon dioxide and carbon monoxide (carbide), between about 455 ~ 860 ℃ in air, diamond will appear graphitization combustion;No oxidation in the inert or reducing gas, but in about 1430 ℃, the diamond crystals will suddenly burst into graphite by.Therefore, diamond bits must be designed, manufactured and used to avoid high impact loads on diamond materials and ensure timely cooling of diamond cutting teeth.

Iii. Status of diamond tools

Diamond tools are widely used in geological exploration, stone, machinery, automobile and national defense industries, etc. The manufacturing technology level of grinding tools, geological drills and stone saw cutting tools for machining has been greatly improved.Our products have been serialized and standardized, with complete specifications, stable quality and competitive ability in the international market.Most diamond monocrystals are used to make various diamond tools.The diamond saw cutting tools produced in China have complete specifications and stable quality.According to statistics, diamond drilling tools can basically meet the market demand in recent years.With the development of construction industry and the popularization of household air conditioner, used in pipeline installation and air conditioning machine installation and old building renovation, construction with diamond thin wall engineering bit demand is also increasing, used in oil, coal field exploration of PDC bit demand also increases accordingly, produced in China on the quality of PDC is not pass, remains to be further research to improve, continuously improve product quality, change the situation currently imports PDC bit.

In machining, diamond grinding wheel, PCD tools and tools, honing oil stone, finishing roller and drawing die are widely used.The performance of the polycrystalline diamond drawing die is better than that of natural diamond die and hard alloy die. Therefore, many applications are made in the wire drawing industry, especially the appearance of CVD diamond drawing die, which provides reliable wire drawing tools for controlling wire materials under 15mm.PCD cutting tools are mainly used in the processing of non-ferrous and non-metallic materials. It is reported that the demand for PCD cutting tools is increasing year by year in automobile, motorcycle, household appliances, wood processing and general machinery industries.Although various diamond tools produced in China have been widely used in various industries and achieved remarkable economic benefits, there is still a certain gap between their technological level and that of foreign similar products, which is mainly reflected in:

1. The whole diamond tool industry lacks unified management and macro-control.Due to blind development, the whole production layout of diamond tools appears scattered, disorderly and blossoming everywhere. The quality of products in the tool market is unstable, the competition is disorderly and the price is chaotic.

2, because of the diamond single crystal production and the development of diamond tools are not harmonious, make the development of diamond tools in China lags behind the growth of diamond single crystal production, cause the backlog of diamond and slow-moving, influence and restrict the sustainable development of the diamond industry in China, serious landslide diamond production enterprise economic benefits.

3. The application field of diamond tools is narrow, the product variety is single, the quality is not stable, and some product technical quality standards are confusing, and there is no unified management standard and standard for product quality inspection and supervision.

4. The production equipment and overall technical level of diamond tools are relatively backward, and some advanced new technologies and new technologies are slow to be promoted and applied.

5. The scale of production enterprises is generally small, the production is not concentrated, the technology is poor, the market competitiveness is lacking, and the economic efficiency is not high.

6. Insufficient investment in diamond tools production, new product development and technological research.

7. During the use of diamond tools, the use rate of matrix materials is low and the steel waste is serious.In the process of use, there are many diamonds that are not normally worn, shed and left, which makes the actual utilization rate of diamond is low and the waste of diamond materials is large.