A test stand fo reciprocating screw plastification units was designed. The melt temperature was measured by an infrared sensor, one fixed and one radial moveable thermocouple. Therefore the axial melt temperature distribution could be determined. Temperatures at the barrel wall were calculated based on measurements of the barrel temperatures at two different radial positions. Inside of a hollow screw there were thermocouples in the feeding zone, the compression zone and the metering zone. These temperature signals were transmitted to a data acquisition system via telemeter. With an increase in screw circumerence speed an increasing portion of the pellets are deflected in the direction of the screw rotation which is caused by momentum forces and frictional forces between the pellets and the screw. A dependence of the plastification rate on the injection speed was found. The axial melt temperature profile in front of the screw can be measured by injection of the plastic melt through a nozzle which holds an infrared sensor. The original melt temperature profile of the cushion can be determined by using a special algorithm which subtracts the pressure induced heating from the measured melt temperature profile. An instrumented test stand was used to check the efficency of ceramic components and the influence of a chamfered flight of the screw tip.