Blowmolding also known as blow forming is a manufacturing process by which hollow plastics parts are formed. In general, there are three main types of blow molding: extrusion blow molding, injection blow molding, and stretch blowmolding. The blowmolding process begins with melting down the plastic and forming it into a parison or preform. The parison is a tube-like piece of plastics with a hole in one end in which compressed air can pass through. The parison is then clamped into a mold and air is pumped into it. The air pressure then pushes the plastic out to match the mold. Once the plastic has cooled and hardened the mold opens up and the part is ejected.
Typical challenges in recycling.
Most blowmolding is done in the packaging industry for common products such as plastics bottles, barrels and bulk containers for the chemical industry, as well as technical parts such as tables or automotive parts.
Mostly recycling in these industries is done in-house. For small plastics bottles the A slow speed granulators are very well suited. Bigger plastic bottles and canisters can be processed in the compact soundproofed C series, they can be used to recycle PET preforms as well. Larger parts such as plastic barrels, car tanks, tables and so on can be processed with the H heavy-duty granulator series, which are able to handle the solid top and tail flush as well.
For extremely big volume parts such as IBCs a shredder/granulator combination is commonly used, here the V shredders with their large volume hoppers offer an optimal solution.
Typical plastics blow molded products
H 80-200 heavy-duty granulator with screw type force feeder for plastic bottles or other pre shred materials