Theoretical estimation of punch velocities and displacements of single-punch and rotary tablet machines

Abstract

The speed of travel of punches during compaction by a Manesty F3 single punch and D3B Rotary punch tablet machine has been derived from machine dimensions, normal operating speeds and by consideration of the consolidation of a theoretical compact. The analysis may also be used for machines with other dimensions, operating at different speeds with other materials, but would require modification if the punch head design on the rotary machine differed significantly. Punch speeds at the beginning of the compression cycle were similar for the two types of machines, namely 10.36 and 10.24 cm s-1 for the single and rotary machines. The time to reach maximum compression and the total time of contact between punches and powder for the single punch machine was 0.1 s for a compaction force of approximately 40 KN. For the rotary machine operating at approximately the same force, these two parameters were found to be 0.052 and 0.083 s respectively. The additional contact time is associated with a period during which there is no vertical movement of the punch, providing a 'dwell' time of 0.0314 s when the powder is held at a constant volume.

Chitin and Chitosan as Direct Compression Excipients in Pharmaceutical Applications

“…These results contradict the early findings of Sawayanagi et al [ 45 ], probably due to the method of compression they were using. In the later work, a hydraulic tablet press with a compression duration time of 30 s was used for tablet compression whereas in the former work [ 46 ] a single station tableting machine was used with a dwell time generally estimated to be less than 0.1 s [ 47 ].…”

Comparison of Calculated and Experimentally Determined Punch Displacement on a Rotary Tablet Press Using both Manesty and IPT Punches

“…To d o this it is necessary to provide the system with co-ordinates of punch position with respect to time". Punch displacement profiles can be calculated from machine and punch geometry for each press using the equations of Rippie & Danielson (1981) or Charlton & Newton (1984). However, these calculations d o not take machine deformations and deflec- tions into account, and as shown in Fig.…”

Calculation of Punch Displacement and Work of Powder Compaction on a Rotary Tablet Press

“…During the compression cycle, the slope at the point of contact for both the punch head and the pressure roll must be the same. Using this relationship we derived an equation similar to that of Rippie & Danielson (I98 1) and of Charlton & Newton (1984). Calculated displacements, however, as pointed out by Armstrong & Palfrey (1987), only describe punch movement into and out of an empty die, i.e.…”