Supported Polycrystalline Diamond Blanks Introduction:
The appearance of synthetic diamond polycrystalline wire drawing die develops a new way for the manufacture of diamond wire drawing die. In 1978, China first developed a wire drawing die made of synthetic diamond material. Through the continuous exploration and summary in recent years, there has been a new development in the wire drawing die, that is, adding a tungsten carbide ring to the periphery of the artificial polycrystalline block to strengthen the supporting polymer, thus improving its strength and impact resistance.
The so-called polycrystalline diamond is a polycrystalline diamond formed by the polymerization of many very small single crystals of diamond particles (between about 1 micron and 10 microns in diameter). The properties of this kind of polycrystalline diamond, are quite comparable to those of natural diamond , apart from its opacity. Wire drawing die made of synthetic polycrystalline diamond has good wear resistance, uniform wear of hole wall, strong impact resistance, high drawing efficiency and low price. Its price is only 1/3 of that of natural diamond drawing die. Therefore, it has been widely used in the current wire drawing die industry, gradually moving towards polycrystalline diamond dies instead of natural diamond dies.
Advantages of Polycrystalline Diamond Wire drawing Die Blanks:
1. Good wear resistance
Synthetic polycrystalline diamond used in the manufacture of wire drawing die, polymerized at high pressure (about 70, 000 atmospheres) and high temperatures (about 1600 ℃), after careful selection of fine quality artificial diamond particles (single crystal, plus less silicon, titanium and other binders. The service life of polycrystalline diamond is long because of high hardness and good wear resistance . It can be said that it is the best material known for wear resistance at present. The service life of polycrystalline diamond wire drawing die is over three times longer than that of natural diamond wire drawing die and 20 times higher than the cemented carbide wire drawing die.
2.Uniform wear of die hole wall
In the drawing process of polycrystalline diamond wire drawing die, the inner wall of die hole is worn evenly so that the drawing wire has high precision and good roundness, which can ensure the consistency of wire rod, thus prolonging the service life of drawing die. Why is the wear of the die hole of polycrystalline diamond wire drawing die uniform? The fundamental reason is that it is a polycrystalline polymer and there is no anisotropy. Natural diamond is the hardest material in the world. Its absolute hardness is 150 times that of corundum and 1150 times of quartz. From the crystallography, we can see that natural diamond is single crystal, which belongs to equiaxed crystal system. It has different crystal plane hardness, in other words, it is anisotropic, even if it is the same crystal face. Different orientation is also with different hardness. The hardness of octahedron is greater than that of dodecahedron, and the hardness of dodecahedron is greater than that of cube.
3. Strong impact resistance
Polycrystalline diamond, which is composed of metal and metal, and diamond particles, is randomly oriented and arranged irregularly. Therefore, it not only has the toughness of cemented carbide, but also has the hardness of natural diamond. Its mechanical strength is better than that of natural diamond, and its impact resistance is strong. In the process of producing drawing die, there are many working procedures, which will produce different degrees of vibration and extrusion in each process. Obviously, it is adverse to the processing of natural diamond that the die hole is cracked or broken because of large vibration or not uniform force, which results in scrapping. For the processing of polycrystalline diamond, it can withstand large vibration and pressure because of its good toughness and high strength, resulting in fewer cracks or breakages, thus improving the product qualification rate and reducing the manufacturing cost. In the same way, in the process of drawing wire, the force on the surface of die hole is more complicated. Some parts are in the state of extrusion, some parts stretching. And at the same time, the vibration is large under the condition of high speed wire drawing. But the polycrystalline diamond wire drawing die can bear, and is more stable than the natural diamond wire drawing.
4.High wire drawing efficiency
Before the appearance of the polycrystalline diamond wire drawing die, the tungsten carbide wire drawing die was used for the larger specification wire (wire diameter > 0.5mm). However, with the continuous development of wire drawing technology, wire drawing equipment is also updated. High-speed wire drawing machines continue to emerge, from the original drawing several meters per second to the present drawing four or fifty meters per second. Therefore, tungsten carbide die it is difficult to apply for tungsten carbide for this high-speed wire drawing. Otherwise the service life is obviously reduced, the auxiliary time of changing mould is increased, and the drawing efficiency is low. If large grain natural diamond is used to produce large size wire drawing die, it is not only expensive, but also lack of resources, which can not guarantee the supply of goods. In view of this situation, it can solve this contradiction using polycrystalline diamond to make large scale wire drawing die. It is with high hardness, good wear resistance, strong impact resistance which can appy to high speed drawing wire with good quality. The long service life of the die reduces the auxiliary time of changing the die and greatly improves the drawing efficiency. In recent years, many wire drawing manufacturers have gradually replaced the tungsten carbide wire drawing die with polycrystalline diamond drawing die, which not only reduces the cost of the die, but also improves the production efficiency. After using polycrystalline diamond wire drawing die, remarkable economic benefits have been obtained.