FORCE-TIME-CURVES OF A MODERN ROTARY TABLET MACHINE .1. EVALUATION TECHNIQUES AND CHARACTERIZATION OF DEFORMATION-BEHAVIOR OF PHARMACEUTICAL SUBSTANCES

According to the geometry of punch heads and the interdependent punch movements force-time-curves of a rotary-tablet press are divided into periods by the aid of the signal of an inductive sensor. The decrease of compaction load in the interval of the flat punch top is mainly due to plastic flow of the compressed substances. Brittle or plastic defo rmation behaviour is easily distinguished and quantified by the combin ation of a standard press and a highly advanced data acquisition and o ff-line software evaluation. Additionally it is shown that there is no need to use a complex equipment for displacement measurement to gathe r reliable data on compaction mechanisms. Even if the machine deformat ion is considered, calculated displacement data may surpass measured d ata in precision.