Abstract: A melt indexer system for determining the melt index of a plastic by testing. The melt indexer system comprises a plurality of melt indexers, each of the melt indexers including a melt chamber into which a sample of plastic to be tested is placed, a heater for melting the sample to a predetermined temperature and a test piston for extruding the melted sample through a calibrated orifice of a removable die to determine the viscosity of the sample as a function of its temperature. A robot arm and a computer programmable to control the movement of the robot arm are provided. An infeed queue holds in predetermined order a plurality of containers containing samples to be tested and a bar code reader identifies each sample to be tested. A test computer associates a particular sample with a predetermined plan for testing the sample, records and processes the melt index test results. A vacuum sipper extracts a charge of the sample from the sample container and places it in the melt chamber.