Injection Molding

Southeastern Container Injection Molding Process

Polyethylene Terephthalate (PET) resin is used to make all of the preforms and bottles that Southeastern Container (SEC) produces. SEC uses over 10 different types of PET resins and colorants to produce approximately 41 different SKU’s for the Coca-Cola bottling system. The PET resin is transported by tanker or railcar from the resin supplier to an SEC facility. Once on site, the PET is pumped via a vacuum system into silo for storage before use. The PET is then pumped from the silo to our blending system or directly to a resin drying system. The blending system allows us to mix in post-consumer material and internal SEC regrind into the virgin PET. Once the resin is in the drying system, it is heated to approximately 350 degrees F. and dried to less than 50 PPM of moisture.

The resin then enters the feed throat of the injection machine and is picked up by the screw that processes the resin from a solid to a syrup like consistency. The liquid resin is stored in the heated shooting pot and then injected into the mold where it is formed into as many as 144 preforms. The injection cycle can take anywhere from 26 seconds to less than 8 seconds depending on the size of the preform. After a short cooling period inside the mold, the mold opens and the preforms are transferred into a robot plate (and then a cool pic on some machines) for more cooling time before they are ejected onto the conveyor. The conveyor then carries the preforms to an SEC preform bin (or box). The bin is then picked up by an Automatic Guided Vehicle (AGV) which transports the bin through a labeling station where a unique bar coded label is attached to two opposite sides. The AGV then drops the labeled bin off at the unloading station where a lid is placed on top before the finished bin is moved to the warehouse for storage.