1. Introduction
PCD (polycrystalline diamond) wire drawing die core, as an important superhard material tool, plays a key role in the drawing process of metal wire, especially high-precision and high-performance wire. This research report aims to comprehensively and in-depth explore the performance characteristics, preparation process, application status and development trend of PCD wire drawing die core, and provide valuable reference information for researchers, engineers and corporate decision makers in related fields.
2. Performance characteristics of PCD wire drawing die core
(I) High hardness and wear resistance
PCD is sintered by many tiny diamond single crystal particles under high temperature and high pressure conditions. Its hardness is second only to natural diamond and has extremely high wear resistance. During the wire drawing process, it can withstand the severe friction between the wire and the die core, maintain the dimensional accuracy and surface roughness of the die core for a long time, thereby ensuring the quality stability and dimensional consistency of the drawn wire. For example, when drawing high-strength steel wire, the service life of the PCD wire drawing die core can be increased by dozens or even hundreds of times compared with the traditional cemented carbide die core.
(II) High thermal conductivity
Diamond has excellent thermal conductivity, and PCD wire drawing die core inherits this property. During the wire drawing process, the temperature of the die core will rise rapidly due to frictional heat generation. Good thermal conductivity can quickly dissipate heat, avoid local overheating of the die core, reduce the risk of die core cracking or deformation caused by thermal stress, and also facilitate the cooling of the wire, improving the stability and production efficiency of the drawing process.
(III) Low friction coefficient
The friction coefficient between PCD and metal wire is relatively low, which not only reduces the energy consumption during the drawing process, but also reduces the scratches and wear on the wire surface, which is conducive to improving the surface quality of the drawn wire, especially for some precision wires with high requirements for surface finish, such as ultra-fine copper wire and gold wire used in the electronics industry, PCD wire drawing die core has obvious advantages.
III. Preparation process of PCD wire drawing die core
(I) Raw material selection and pretreatment
The main raw material for preparing PCD wire drawing die core is diamond micropowder, and its particle size, purity and crystal structure have a significant impact on the performance of the final product. Usually, diamond micropowders with uniform particle size, high purity and high strength are selected and surface treated, such as removing impurities and surface activation, to improve the bonding force between diamond micropowders.
(II) High temperature and high pressure sintering
After the treated diamond micropowders are evenly mixed with an appropriate amount of metal binder (such as cobalt, nickel, etc.), they are loaded into a special mold and sintered in a high temperature and high pressure equipment (such as a six-sided top press). The sintering temperature is generally 1200℃ - 1500℃, and the pressure is 5 - 6 GPa. Under the action of high temperature and high pressure, the diamond micropowder reacts with the metal binder to form a strong polycrystalline structure. The process parameters (such as temperature, pressure, time, metal binder content, etc.) during the sintering process need to be precisely controlled to obtain the ideal PCD structure and performance.
(III) Subsequent processing
The sintered PCD blank needs to undergo a series of processing such as cutting, grinding, and polishing to make a finished product that meets the size requirements and precision standards of the wire drawing die core. Among them, the grinding and polishing process is particularly critical, which directly affects the inner hole size accuracy, surface roughness and shape accuracy of the mold core. In recent years, with the development of ultra-precision processing technology, advanced technologies such as laser processing and ion beam processing have gradually been applied to the processing of PCD wire drawing mold cores, further improving the processing accuracy and quality of the mold core.
IV. Application status of PCD wire drawing mold cores
(I) Metal wire drawing industry
PCD wire drawing mold cores are widely used in the drawing of various metal wires, including steel, non-ferrous metals (such as copper, aluminum, zinc, tin, etc.) and precious metals (such as gold, silver, platinum, etc.). In the steel industry, it is used to draw high-strength steel wire, steel wire for wire rope, etc.; in the electronics industry, it is a key tool for drawing ultra-fine copper wire, gold wire, silver wire, etc. for manufacturing electronic components and integrated circuit connection wires; in the jewelry industry, it can draw precious metal wires for making necklaces, bracelets, earrings and other accessories.
(II) Other fields
In addition to metal wire drawing, PCD wire drawing cores are also used in the wire drawing processing of some special materials, such as high-performance fiber materials such as carbon fiber and glass fiber. These materials have the characteristics of high strength and high modulus. Ordinary wire drawing cores are difficult to meet their drawing requirements. PCD wire drawing cores can effectively draw them with their high hardness and wear resistance, expanding the application range of high-performance fiber materials.
V. Problems and challenges of PCD wire drawing cores
(I) High cost
The preparation process of PCD wire drawing cores is complex, requiring high temperature and high pressure equipment as well as high-quality diamond powder and metal binder, resulting in relatively high production costs. This has limited its large-scale application in some cost-sensitive industries to a certain extent, especially in some low-end metal wire drawing markets, where traditional carbide cores still dominate.
(II) Difficulty in improving the precision of inner hole processing
The extremely high hardness of PCD materials poses great challenges to the precision processing of the inner hole of the core. Although there are many advanced processing technologies, it is still difficult to achieve ultra-high precision inner hole processing (such as nano-level dimensional accuracy and extremely low surface roughness). This is an urgent problem to be solved for some application fields that require extremely high wire precision (such as ultra-fine wire drawing, high-precision sensor wire manufacturing, etc.).
(III) Insufficient research on compatibility with different wires
The physical and chemical properties of different metal wires and special materials are quite different, and the wear mechanism and friction characteristics of PCD wire drawing die cores during the drawing process are also different. At present, the research on the compatibility of PCD wire drawing die cores with various wires is not deep enough and systematic, and it is difficult to optimize the performance and structural design of the die core for different wires, which affects the further optimization of the drawing process and the improvement of wire quality.
VI. Development trend of PCD wire drawing die cores
(I) Research and development of low-cost preparation technology
In order to reduce the production cost of PCD wire drawing die cores, the future will focus on the research and development of low-cost diamond micropowder synthesis technology, new metal binder system and optimized high temperature and high pressure sintering process. For example, explore the use of a new chemical vapor deposition (CVD) method to synthesize low-cost, high-quality diamond micropowder, develop cobalt-free or low-cobalt metal binders to reduce raw material costs and improve PCD performance, and improve the efficiency of high-temperature and high-pressure sintering processes and product quality stability through computer simulation and optimization of process parameters.
(II) Ultra-precision processing technology innovation
With the continuous improvement of wire precision requirements in modern manufacturing, the ultra-precision processing technology of PCD wire drawing die cores will continue to innovate and develop. On the one hand, traditional processing technologies (such as grinding and polishing) will continue to be improved and optimized to improve processing accuracy and efficiency; on the other hand, emerging ultra-precision processing technologies (such as femtosecond laser processing, focused ion beam processing, etc.) will be more widely used and deeply studied, and are expected to achieve nano-level ultra-precision processing of the inner hole of PCD wire drawing die cores to meet the future needs of ultra-fine wire drawing and high-end precision manufacturing.
(III) Personalized customization and adaptability research
In view of the characteristics of different wires and drawing process requirements, the personalized customization and adaptability research of PCD wire drawing die cores will be strengthened in the future. Through in-depth research on the friction and wear mechanism, heat transfer characteristics, etc. between the wire and the die core, PCD wire drawing die cores with different organizational structures, performance characteristics and surface treatment methods are developed to achieve the best adaptation to the drawing of different wires, improve the stability of the drawing process and the quality of the wire, and expand the scope of use of PCD wire drawing die cores in more special materials and high-end application fields.
VII. Conclusion
As a high-performance wire drawing tool, PCD wire drawing die cores have many excellent properties such as high hardness, high wear resistance, high thermal conductivity and low friction coefficient. They are widely used in metal wire drawing and other special material drawing fields. However, it still faces problems such as high cost, difficulty in improving the inner hole processing accuracy, and insufficient research on compatibility with different wires. In the future, with the research and development of low-cost preparation technology, ultra-precision processing technology, and in-depth development of personalized customization and adaptability research, PCD wire drawing die cores are expected to be more widely used in more fields, providing strong support for the development of modern manufacturing industry.
