Patent ID: 8361360

Claim:
A method for controlling a tablet press, whereby powder or granular material is compressed in dies arranged circumferentially in a rotary die table by means of reciprocating punches, said method comprising the steps: consecutively supplying a quantity of material to be compressed into each die, subjecting the quantity of material located in each die to a pre-compression and subsequently a main-compression, measuring a weight value of a parameter representative of the weight of the quantity of material fed into the die, regulating the quantity of material supplied to each die on the basis of a deviation between a previously measured weight value and a first set value, and measuring the weight value during pre-compression of the quantity of material located in each die, characterized in that the main-compression is performed under substantially constant compression force and variable resulting tablet thickness of the individual tablets, whereby the powder or granular material is compressed in the die between opposed first and second punches, each punch having first and second ends, whereby said first punch ends are received in the die, and said second punch ends, during main-compression, interact with first and second main-compression rollers, respectively, whereby, during the main-compression, the first main-compression roller is displaced in the axial direction of the punches and the second main-compression roller is fixed in said direction, and whereby the first main-compression roller is carried by the main-compression piston, whereby a main-compression displacement value representative of a displacement of the first main-compression roller during main-compression is measured, and the position of the second main-compression roller in said direction is regulated on the basis of a deviation between a previously measured main-compression displacement value and a second set value, whereby said position regulation of the second main-compression roller is based on a mean value of several single measured main-compression displacement values, whereby the position of the second main-compression roller is maintained constant as long as said mean value of the main-compression displacement value falls within preset correction tolerance limits, and whereby the position of the second main-compression roller is regulated so that the resulting main-compression displacement value is maintained substantially constant.