Split Die – Automatic

11Compacting a tablet in a die creates very large radial forces on the die wall. When the punch load is released, the residual radial die wall pressure on the tablet will often cause it to fracture or develop stress cracks, and especially when the lower punch pushes it out. At the top of the die, the tablet experiences severe shear stresses as the top of the tablet exits the die first.

To study the compaction properties of pure API’s and any materials that will not make tablets conventionally, a hydraulically actuated “split die” can be used. This allows the radial die wall pressure to be automatically released before ejection.

Optionally, the die wall pressure can be servo-controlled to release pressure in proportion to the axial punch pressure. Effectively, this is “tri-axial” pressure release.

Die Type: Round B or D
Die wall pressure capacity: 300MPa on a 10mm Dia. tablet, 5 mm Thick
Operating pressure: 280 Bar
Pressure control: Automatic On/Off or servo controlled tri-axial pressure.

The results below show ejection force in KN (highlighted yellow) for a series of tests with increasing compaction load. One result is plotted (highlighted blue).