Trace each plastic part from octabin lot and mould cavity to the packed carton, with its shift sheet.

Plastic trades share a start. Resin or compound arrives in bags, octabins or silos, is dried in a dehumidifier because nylon is hygroscopic, or blended with masterbatch, and is melted in a barrel. What comes out depends on the process. An injection moulder runs a tool on a press, a blow moulder forms bottles from a parison, and an extruder draws pipe, film or profile through a die.

A job carries its own records. These are the customer order, the mould or die number, the resin grade and lot, the press, the cycle settings and a shift log of shots, kilograms and rejects. Packaging makers add artwork versions and sealing jaw settings. Component makers add brass inserts, overmoulding and customer part numbers. Engineering plastics processors add dryer settings, hopper moisture checks and a certificate for each nylon, polycarbonate or halogen free lot, because wet pellets show up later as splay and brittle parts.

Mould makers sit one step earlier. Their output is the tool. They build and repair the cores, cavities, lifters and hot runner systems that the others run, so their work is quoted, spark eroded, trialled and handed over against drawings. Every trade ends in inspection, packing and dispatch, and each of those steps needs the lot, the tool and the shift written down before the goods leave the gate. A tool in repair stops orders. A mixed-up lot can do the same, once it is found after the cartons are packed and booked onto a truck.