Pre-compression tablet thickness became a standard control in the mid-1970s on tablet presses manufactured in Europe. Indeed, as seen in photo 1 below, older press manuals and control labels sometimes use the term "tamping" in place of thickness when describing the control itself. An examination of this term helps to understand the intention of this critical setting.


Photo 1: A pre-compression thickness setting on a 1980 tablet press. Note that the label states "tamping".

What exactly is a tamp, anyway? A tamp is a device used to compact or flatten an aggregate or powdered / granular material, typically to make it resistant to further compression or simply to increase its density. In many countries the term is also described as pre-compression tablet thickness for clear understanding.

Note the language used in a typical operation manual:

"Pre-compression is the preliminary compression force that tablet presses apply prior to the main compression. Operators often unknowingly set compression levels improperly, utilizing a percentage of the final compressive force, and this isn't a recommended practice. Precision in pre-compression is crucial.

If an operator applies excess pre-compression, chances increase that tablets will fracture. On the other hand, if operators do not apply sufficient pre-compression, there will be increased air entrapment in the formulation. In the presence of fractures, the top of a pre-compression tablet, or its cap, may break away from its main body. This occurrence is tablet capping, and it most often happens as a result of trapped air in the powder material during pre-compression."


If you have any technical questions, please contact with Grace Chiang Email:grace.chiang@yenchen.com.tw
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