Plastic Injection Molding - 1

Injection molding is the heart of automotive industry as more than 90% of the plastic or rubber or glass used in an automotive is moulded in it to acquire final shape & standards required. You just name a plastic part & from as small as fasteners to as big as Inst. Panel, everything is injection molded.

• Granulated or powdered thermoplastic plastic is fed from a hopper into the Injection Moulding machine.

• A hollow steel barrel, containing a rotating screw (Archemidial Screw) , carries the plastic along the barrel to the mold.

• Heaters surround the barrel melt the plastic as it travels along the barrel.

• The screw is forced back as the melted plastic collects at the end of the barrel.

          Once enough plastic has collected a hydraulic ram pushes the screw forward injecting the plastic through a nozzle into a mould cavity. 

     The mould is warmed before injecting and the plastic is injected quickly to prevent it from hardening before the mould is full.

    Pressure is maintained for a short time (dwell time) to prevent the material creeping back during setting (hardening). This prevents shrinkage and hollows, therefore giving a better quality product.

  

First Half Of Molding Machine

Front half of the mold, called the mold cavity, is mounted to a stationary platen and aligns with the nozzle of the injection unit.

    

     The molding is left to cool before removing (ejected) from the mold. 

Second Half Of Molding Machine

Rear half of the mold, called the mold core, is mounted to a movable platen, which slides along the tie bars.

Hydraulically powered clamping motor actuates clamping bars that push the movable platen towards the stationary platen and exert sufficient force to keep the mold securely closed while the material is injected and subsequently cools.