THE DIMENSIONING OF AN EXTRUSION PRESS

In connection with investigations on a so called ram or piston feed lock for introducing solids into, or discharging solids from, pressurized spaces, which operates on exactly the same principle as an extrusion press, the question as to the relationship between the piston pressure to be applied and the length to be adopted for the die channel has to be considered. The criterion is that a particular compaction pressure must not be exceeded. A consistent distinction is drawn between the compaction phase and the extrusion (or conveying) phase. On the basis of theoretical considerations relating to bulk materials and correspondingly different formulations for the pressure conditions established, it is possible to obtain a differential equation whose solution yields an unambiguous relationship between compaction pressure and required channel length. A dimensionless representation of the results based on this approach offers a simple method of determining the dimensions of extrusion presses taking due account of the compaction phase and the extrusion phase.