What causes capping and lamination during tablet production?

Answer 1

They occur as a result of elastic recovery (i.e. expansion) of the tablet when it gets compressed. This expansion happens both axially and radially. Capping tend to occur during ejection from the die cavity whereas lamination usually occurs when the tablet is still in the die cavity. For lamination, axial expansion can occur whereas it is harder for radial expansion to happen due to the residual die wall pressure. This will result in the tablet splitting into different layers.

Answer 2

Lamination and capping can be reduced by compressing the tablets in a vacuum environment. More components can also be added to increase bonding. In addition, gradual loading and unloading with pre-compression may also reduce the occurrence of lamination or capping.

Answer 3

The causes of capping and lamination include air being trapped in the tablet which prevents bond formation or the materials of the tablet having little cohesive properties. To avoid air being trapped in the tablet, the rate of compression can be reduced to allow the air to escape. Multistage compression presses can also be used so that the air is released more slowly before final compression. As for the material having little cohesive properties, the addition of a "plastic" component may fix this problem. The stress relaxation time can also be increased by using pre-compression or by slowing the production rat.

Answer 4

They may be caused by air entrapment during compression, elastic relaxation, and poor bonding.