Abstract: System and apparatus for carrying out a thermoplastic material molding process wherein mutually abutting carriage conveyed clamshell molds are driven along a single track locus having vertically disposed tunnel forming and return region. Thermoplastic material is expressed vertically downwardly from a die nozzle located above the forming tunnel entrance elevation and with a diameter corresponding with but slightly less than the maximum diametric extent of a mold cavity within the mold sequence. Where a given mold cavity portion exhibits a minimum or zero cross dimension, the mold cavity is structured having an adjacent accommodation mold cavity portion of greater cross dimension.