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What is the Working Principle of the Tablet Press?

Aug. 09, 2021

As a China Pharmaceutical Equipment Factory, I would like to share with you.

1. Punch and die: Punch and die are the basic parts of the tablet press. Each punch die is composed of three parts: upper punch, middle die and lower punch. The structure of the upper and lower punches are similar, and the punch diameters are also the same. The punches of the upper and lower punches are matched with the die hole of the middle die and can slide up and down freely in the middle die hole, but there is no gap that can leak the powder . The processing size of the die is a unified standard size, which is interchangeable. The specifications of the die are expressed by the diameter of the punch or the hole diameter of the middle die, generally 5.5-12mm, each 0.5mm is a specification, and there are 14 specifications in total.

The punch and die are subjected to a lot of pressure during the process of tableting. They are usually made of bearing steel and are heat treated to increase their hardness.

Tablet Press Machine

Tablet Press Machine

There are many types of punches, and the shape of the punch depends on the shape of the tablet. According to the structure and shape of the die, it can be divided into round and special shapes; the shape of the cross section of the punch includes flat, hypotenuse, shallow concave, deep concave and comprehensive shapes. The flat and beveled punches are used to compress flat cylindrical tablets, the shallow concave is used to compress biconvex tablets, the deep concave is mainly used to compress the chips of coated tablets, and the comprehensive shape is mainly used to compress Shaped flakes. In order to facilitate the identification and taking of medicines, the name of the medicine, dosage and vertical and horizontal lines can also be engraved on the end face of the die. To compress tablets of different doses, a die of a suitable size should be selected.

2. The working process of the tablet press

The working process of the tablet press can be divided into the following steps:

①The punch position of the lower punch extends into the middle mold hole from the lower end of the middle mold hole to seal the bottom of the middle mold hole;

② Fill the hole of the middle mold with medicine using the adder;

③The punch part of the upper punch falls into the middle mold hole from the upper end of the middle mold hole, and goes down for a certain stroke to compress the powder into tablets;

④The upper punch lifts out the hole, and the lower punch rises to push the tablet out of the middle die hole to complete a tablet pressing process;

⑤The undershoot is lowered to the original position, ready for the next filling.

3. The principle of tablet pressing mechanism

①Dose control. Various tablets have different dosage requirements. Large dosage adjustment is achieved by selecting punches with different punch diameters, such as punches with diameters of 6mm, 8mm, 11.5mm, and 12mm. After the size of the die is selected, the tiny dosage adjustment is to adjust the depth of the lower punch into the middle die hole, thereby changing the actual length of the middle die hole after the bottom is sealed, and adjusting the filling volume of the drug in the die hole. Therefore, there should be a mechanism for adjusting the original position of the lower punch in the die hole on the tablet press to meet the dosage adjustment requirements. Because different batches of powder preparations always have differences in specific volume, this adjustment function is very necessary.

In the dosage control, the action principle of the feeder also has a considerable influence. For example, when the granular medicine relies on its own weight, when it rolls freely into the hole of the middle mold, the filling condition is relatively loose. If multiple forced entry methods are used, more drugs will be filled in the die hole, and the filling will be denser.

②Control of tablet thickness and degree of compaction. The dosage of the drug is determined according to the prescription and pharmacopoeia and cannot be changed. In order to require storage, transportation, preservation and disintegration time limit, the pressure of a certain dose is also required during tablet compression, which will also affect the actual thickness and appearance of the tablet. Pressure adjustment during tableting is essential. This is achieved by adjusting the downward movement of the upper punch in the die hole. Some tablet presses not only have upward and downward movements in the process of tablet pressing, but also can have downward and upward movements, and the relative movement of the up and down punches together completes the tablet pressing process. However, pressure adjustment is mostly achieved by adjusting the upward and downward movement of the mechanism to achieve pressure adjustment and control.

Our company also has Tablet Press Machine on sale, welcome to contact us.

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