In pharmaceutical production, tablet pressing is a common process. However, in the process of tablet pressing, many users will find the problem of sticking and punching, that is, the powder particles adhere to the surface of the punch and can not form a smooth sheet, which makes the tablet products unqualified. So, how to solve this problem?
Stick punching may occur at any stage of the tablet pressing process, but it can be foreseen. Measuring the moisture content of particles can help users predict whether the product is stick punching or not. The reason of stick punching may be related to the product, equipment, upstream process or tablet press operation, or it may be a combination of several factors.
First, product problems. When the product is pressed for a time, the operator needs to adjust the weight of the tablet first, and then adjust the thickness of the tablet. The hardness of the tablet was determined by the weight, thickness, pressing speed and holding time of the tablet.
For some pressure sensitive particles, if there is a problem of sticking and punching, you can quickly press several circles of hard pieces, use the pressure to make the particles stick to the synthetic piece, and take away the powder stuck on the punching. However, it is necessary to pay attention to the pressure. If the load of the die is exceeded, the die may be damaged or even broken.
In addition, experienced operators can also judge whether to stick or not by the sound of the tablet press. If there is a phenomenon of sticking and punching, the pressure setting can be changed, such as increasing the pressure, reducing the sheet thickness, reducing the pre pressing thickness, or reducing the pressing speed.
Second, equipment. The user needs to choose a regular die equipment manufacturer, because the manufacturer will generally do some work to avoid sticking and punching problems. Conditional users can also customize the die with adhesion characteristics, and also change the height and angle of lettering to reduce the risk of stick punching.
In addition, the brightness of the steel surface may also occur stick punch. For example, D2 and 440C steels contain more chromium than other types of steels, which can reduce stick punching. At the same time, special chrome coating can be used to form a high hardness and wear-resistant die.
Third, air interception. It is understood that in the process of tablet pressing, air may be drawn into the concave surface of the punch, making the air form a soft area on the surface of the tablet, causing stick punching. In addition, this happens when the film is soft.
For this kind of situation, the solution is to ensure the proper holding time, discharge the trapped air, and also increase the main pressure discharge as much as possible. If the above adjustment can not be achieved, the conical die can be considered to help air discharge.
Fourth, there is no proper lubrication. The function of the lubricant is to prevent the powder from adhering to the die, the middle die and other metal substances in the process of tablet pressing, and also to promote the arrangement of tablets. But users also need to pay attention to the correct use of lubricants, otherwise they can not play a role correctly. Generally speaking, pretreatment is required to eliminate lumps or relatively large particles, and the lubricant should be mixed evenly. In addition, excessive lubrication is not allowed, otherwise, sticking and flushing will occur.
Fifth, the upstream process. For example, improper use of adhesives, incomplete drying of products, etc., will also occur. Therefore, we should solve different problems accordingly.
In conclusion, one or more factors may be related to the sticking and punching during tablet pressing. Users need to check the causes from the upstream and make solutions in a timely manner when ensuring that the equipment is free of problems.