Factors of the die itself
- PCD material quality: the purity of diamond particles, particle size distribution and the performance of the bonding agent will affect the life of the mold. PCD materials with high purity, uniform particle size and close bonding between bonding agent and diamond can make the die have better hardness, abrasion resistance and impact resistance, and longer service life.
- Mold manufacturing process: When preparing PCD cores, the control of high temperature and high pressure sintering parameters is crucial, and improper parameters will lead to defects within the PCD cores, reducing mold performance. The precision and quality of cutting, grinding, polishing and other machining processes will also affect the mold life, such as high surface finish can reduce the coefficient of friction, reduce wear.
- Mold structure design: reasonable entrance area, lubrication area, working area, sizing area and exit area design can make the wire drawing process smoother. For example, the length of the sizing area is unreasonable, too short to ensure the dimensional accuracy of the wire, too long will increase the friction, resulting in accelerated wear of the mold.
Drawing process factors
- Tensile speed: speed is too high, will make the metal wire and mold friction between the intensification of a large amount of heat, may lead to lubricant failure, accelerate mold wear; speed is too low, the deformation of the thermal effect of a small, relatively large friction, but also will make the mold wear serious.
- Deformation degree: If the deformation degree of single drawing is too large, the pressure and friction borne by the mold will increase sharply, which will easily lead to premature wear of the mold or even rupture.
- Drawing temperature: If the temperature is too high, the diamond in PCD may undergo a graphitization transformation, especially for cobalt-based PCD cores at temperatures higher than 650 degrees Celsius, the risk of graphitization increases, which reduces the hardness and wear resistance of the die.
- Lubrication effect: Good lubrication creates an effective lubrication film between the metal wire and the mold, reducing the coefficient of friction and wear. The type and quality of the lubricant as well as the adequacy of the supply will affect the lubrication effect.
- Counter tension: appropriate counter tension can make the metal wire in the drawing process better fit the mold, reduce the relative sliding between the wire and the mold, reduce wear. However, too much counter tension will increase the stress on the mold and may lead to mold damage.
Processed material factors
- Material hardness: The higher the hardness of the metal material being drawn, the greater the wear on the PCD drawing die. If the processing of ultra-high hardness materials, may make the mold wear and tear increased, shortening the service life.
- Material surface quality: the presence of cracks, burrs, scratches and other defects on the surface of the metal wire, or oxide, oil and other impurities, drawing will destroy the lubricating film, so that the friction increases, but also may lead to stress concentration, accelerating mold wear.
- Material organization uniformity: uneven organization of metal materials, drawing process of uneven deformation of various parts, will make the mold bear the uneven distribution of stress, resulting in uneven wear of the mold, affecting the service life.
Mold use and maintenance factors
- Installation and commissioning: installation if the wire stretching axis and mold hole centerline asymmetry, will make the mold to withstand uneven stress, accelerate wear. In addition, the existence of vibration in the stretching equipment will also cause the mold to be subjected to additional impact, shortening its life.
- Cleaning and Maintenance: Regular cleaning of the mold to remove metal chips, oil and lubricant residue on the surface can prevent these impurities from exacerbating mold wear. Proper maintenance of the mold, such as applying protective oils, can protect the surface of the mold and extend its service life.
- Repair and reuse: molds appear slight wear and tear, timely repair and polishing, can restore the precision of the mold and surface finish, to extend its service life. But the repair process and level is also very critical, improper repair may further damage the mold!
