an injection assembly of low thermal mass which has a molded bearing plate which reduces the total amount of material required and thus the amount of heating or cooling necessary to raise or lower the temperature of the injection assembly . the assembly includes a molded bearing plate with structural ribs and a cast heating distributor connectable to the matrix of an injection mold . the heating distributor has connectors for at least one central nozzle for receiving plastics material and connectors for at least one injection nozzle for injecting the plastics material into the injection mould , and branches containing ducts for transferring the plastics material from the at least one central nozzle to the at least one injection nozzle . the branches include a heater for controlling the temperature of the heating distributor , and at least one central nozzle and at least one injection nozzle .