Tamping Pin Type Capsule Filling Machine Working Principle

Quite a number of high speed automatic capsule filling machines use tamping and dosing disk technology. Of course, this is due to higher production output, consistent quality and reliability, just to mention a few.

Apart from the tamping pin type capsule filling machine, there are other pharmaceutical companies using dosator capsule filling machines. Even though they serve the same purpose (filling capsules), every machine has a unique working principle.

Generally, the process of filling capsules involves:

• Rectification where the machine automatically orients the capsules
• Opening the capsules
• Filling capsules
• Sealing/covering capsules
• Ejecting fully-filled capsules

Whether you choose a dosator or tamping pin type capsule filler, the sequence remains the same. The main difference comes in the process of filling the capsules.

The Working Principle of Tamping Pin Type Capsule Filler

Here is a diagrammatic representation of a tamping pin type capsule filling machine:

As you can see from the figure above, the tamping pin type capsule filling process involves a number of stages. In this case, the machine has 5 stage tamping technology.

So, here is how the tamping pin capsule filling machine works:

First, every dosing disc has a number of holes through its surface as you can see in the 3D image below:

This pan rotates continuously in a circular manner depending on the preset speed. You can see this from this video of the SaintyCo capsule filling machine

From the above image, the tamping plate (“stop” plate) closes the holes on the dosing plate.

Normally, as the dosing plate rotates below the powder bed, the filler material flows into each hole. The pins, which are in the tamping stations compress the powder to a controlled depth.

That is, as the filler material flows into the first hole in the disc, tamping pin 1 compresses it to a predetermined depth.

After this first step, the hole moves to the next stage where the powder again flows into the hole and tamping pin 2 compresses it to a predetermined depth.

The force these tamping pins exert on the powder is just enough to compact it. That is, it may range from 50N to 150N.

This process continues until the holes with the powder reaches the last tamping pin (no. 5), where the machine ejects a compacted powder through the dosing plate into the capsule.

To ensure consistency in the dosing process, all excess powder must be scraped off. It ensures that the final product is smooth and no powder adheres to the surface of the machine.

After filling the capsule shell, it moves to the next stage (sealing/covering the capsule). This is a continuous process and the production speed will depend on the preset machine conditions.

Modification to the Tamping Pin Type Capsule Filling Machine

At times, certain modifications may be necessary to ensure the tamping pin type capsule filler operates optimally. Some of these modifications may include:

• A feedback control mechanism to help regulate force/pressure of the tamping pin in powder dosing stations. It ensures accuracy and consistency.
• Changing the tamping pin size depending on the size of the capsules.

Conclusion

In short, the working principle of a tamping type capsule filler involves a number of stages whose consistency and performance should be monitored. Even though the process seems simple and straightforward, any failure/malfunction in any of the tamping pins may cause serious loss (high rate of capsule rejection).