The injection molder is one of the Polycraft Inventories that can be built at Tech Level 2. An injection molder allows thermoplastic processing of polymer melts. Note that not all polymers can be melt processed. As a rule of thumb, resins, which are thermosets much be processed by conventional means and not through an extruder or and injection molder. To get an injection molder to work, you must supply the proper Mold made from a qualified metal, cooling water and Fuel. The type of polymer pellets used will determine the strength and robustness of the printed part.
This picture demonstrated an automated Injection Molder which uses Pumps, Pipes and simple Flow Networks to automate Input (top left), output (front) and fuel (bottom right).