Plastic Blow Moulding Process
There are different plastic blow moulding process to make a bottle. But what kind of technology should be chosen depends on the characteristics required. What are the exactly molding process? Here we will explain more details about them and their characteristics and comparison.
Plastic Injection Blow Molding Process
Injection blow moulding process can be separated as injection moulding process and blow moulding process.
1. Injection moulding process: The injection molding is finished by an injection molding unit or machine. In this process we will produce a semi-finished product called preform or parison. Raw material is melt in a barrel and feed to the nozzles, injected to a injection mold, then we have the perform with kinds of bottle neck types.
2. Blow Moulding process: The blow molding is we put the performs or prisons to a blowing mold and use high pressure air to blow it up as a bottles or other hollowed containers.
The injection blow moulding process is known as two steps injection blow molding and one step injection blow molding. Preforms whether cooled and reheat to be blown is the evident difference between two steps and one step injection blow molding.
Plastic Injection Stretch Blow Molding Process
Injection stretch blow molding means the preforms must be stretched longer before blowing. It`s is used on longer/high containers or with very good quality products like expensive cosmetic bottles. Injection stretch blow molding process is mostly same as injection blow molding process shown above. The evident difference is stretching. Injection stretch blow molding have the stretch process before blow molding: a stretch rod is hidden inside the preform`s neck core, it will stretch the preforms as longer go have good quality or a thinner thickness.
Please click above picture if you want to lean more details about injection stretch blow molding process.
Plastic Extrusion Blow Molding Process
Extrusion blow moulding process is the largest and the earliest type of blow molding method. It is used to create hollow plastic products. It is suitable for the blow molding of polymers such as PE, PP, PVC, thermoplastic engineering plastics and thermoplastic elastomers, and various plastic blends. Used to produce packaging containers, storage tanks and other industrial parts.
Extrusion blow molding process is start from the material is melted and plasticized in the barrel. And then extruded from the head of the extruder with conventional downward tube.When the hube parison reaches a predetermined length, a section of tube embryo is intercepted and placed in the blow mold while still hot. The mould is closed catching and holding the neck end open and pinching the bottom end closed. the compressed air blown into the parison through the air blowing nozzle. The tube prison will be precisely inflated as the desired shape of the mold cavity. After the mould is completely cooled and then the mold can be opened to take out the product.
