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The dry granulation process is used to produce granules without using a liquid solution because the granulated product can be sensitive to moisture and heat. Powders need to be compacted and densified to produce granules without moisture. Dry granulation can be conducted in a tablet press using slugging tooling or in a roller compactor commonly referred to as a tablet press. When used for dry granulation, the powders may not have sufficient natural flow to feed the product evenly into the die cavity.
The dry granulation process is used to produce granules without using a liquid solution because the granulated product can be sensitive to moisture and heat. Powders need to be compacted and densified to produce granules without moisture.
Sluggers
Dry powders can be compressed using a conventional tablet machine or, more commonly, a large heavy-duty rotary press. This process is often known as ‘slugging’, the compact (typically 25mm in diameter by about 10-15mm thick) produced in the process is called a ‘slug’. A hammer mill is suitable for breaking compacts.
Roller compactor
Roller compaction is an alternative gentle method, the powder mixture is pressed between two rollers to form a compacted sheet. The sheet is usually weak and brittle and breaks into flakes immediately. These flakes require gentle treatment to break them into granules. It can further be milled into the desired particle size.
To determine the end point of the grain
Granulation is more art than science. There are following ways to determine the end point of granularity.
Make a ball of grain in the fist by applying slight pressure. The resulting ball should not be too hard or too soft. It should break after applying slight pressure. The residue after breaking the ball should be granular and not fine.
