Continuous measurement of die wall pressure in a rotary tablet machine

In the pharmaceutical industry, tablets are manufactured using rotary tableting machines. Recently, die wall pressure in a single-punch press was measured to understand the compaction mechanism and predict tableting failure. However, die wall pressure measurements in rotary tableting machines have not been studied. Two challenges exist in measuring die wall pressure in these machines, viz. (i) lack of space inside the machine to set up the measurement equipment and (ii) difficulty in installing wired measurement hardware because the die rotates with the rotary plate. This study aimed to continuously measure die wall pressure in a rotary tableting machine and investigate the effect of high compression speed on die wall pressure. Die wall pressure at tableting speeds of up to 140 mm/s was successfully determined using a wireless telemeter. Residual die wall pressure for plastic materials was strongly dependent on the tableting speed, although the tableting speed affected the maximum die wall pressure minimally. This novel measurement technique can be used to study the effect of tableting speed on die wall pressure, which can be applied in solving the problems of capping and lamination during tablet production.