Views: 0 Author: Site Editor Publish Time: 2021-01-06 Origin: Site
Die material for sheet pressing machine
Die is an important supporting part of the press, the traditional press rod and die are made of steel. During the pressing process, friction will occur between the powder and the punch wall and the upper and lower punch rods, which will reduce the transmission of axial and radial forces of the powder and cause uneven distribution of pores and density in the powder. In serious cases, it will also lead to great changes in the weight of the powder, resulting in fragmentation, lamination, machine damage and other problems. And friction produces heat, which affects the stability of heat-sensitive drugs.
The usual method is to apply lubricant to the die to reduce wear or to replace the punch rod. Most lubricants are hydrophobic substances, which can extend the disintegration time limit of the tablet and prevent water from entering the tablet, so the greater the dosage, the greater the influence. But the commonly used lubricant for magnesium stearate (from the animal body), is not easy to use in large quantities, and the human body if excessive absorption of magnesium stearate, easy to induce stones.
In order to reduce the friction of the die, some researchers came up with the idea of using zirconia instead of steel. Zirconia is an ideal wear resistant material in engineering applications. It has high hardness and wear resistance, thus prolonging the service time of the grinding tools. Low friction coefficient, can reduce the time of powder compression, more importantly, can reduce the time out. In addition, zirconia is antistatic, non-magnetic and has low thermal conductivity, which will not affect the properties of the tablets due to the heat generated by friction, making it an ideal material for the manufacture of die.