33.Aman Industry Bottle Blow Molding Technology Seminar

Bottle blow molding technology is widely used. I hope this article can give some inspiration to friends who want to understand this knowledge.——-Vito.

Aman Industry Bottle Blow Molding Technology Seminar

Aman Team 1

Blow moulding or blow moulding is a manufacturing process that forms hollow plastics. Blow moulded products are made from various thermoplastic materials such as LDPE, HDPE, PET, PP and PVC. 2023 began with the technical team at Aman discussing many types of moulding technology.

Bottle Blow Molding


1. Extrusion blow molding.

Extrusion blow moulding is a method for the manufacture of hollow thermoplastic manufactured parts. Widely known blow moulding objects are bottles, drums, cans, boxes and all containers for packaging food, beverages, cosmetics, pharmaceuticals and household products. Large blow moulded containers are often used for packaging chemicals, lubricants and bulk materials. 3/4 of all blow moulded products are manufactured by the extrusion blow moulding method. The extrusion process forces the material through a hole or die to create the product. The extrusion blow moulding process consists of 4 components:

(1) The plastic profile (extrusion of the hollow plastic tube);

(2) Clamping the flap die closed over the profile, clamping the die and cutting the profile;

(3) Blowing of the mould into the cold wall of the cavity, adjusting the opening and maintaining a certain pressure during the cooling period, opening the mould and removing the blown part;

(4) Trim the flying edges to obtain the finished product.

Extrusion blow moulding.

Aman Team 4

2. Injection blow molding.

The injection blow molding process has developed rapidly in recent years and is used in the production of packaging bottles for the pharmaceutical, food, cosmetic and chemical industries.

Injection blow moulding is a combination of injection moulding and blow moulding to produce hollow products… It is the process of moving from an injection stage to a blow moulding stage. It starts by forming the blanks with an injection moulding machine. The core is then extracted from the concave mould history together with the blank. It is transferred into the blow mould. Finally, compressed air is blown into the mould to cool it down. The injection blow moulding method generally consists of the following steps.

(1) moving the injection moulded core towards the injection moulded cavity and fitting it to the injection moulded cavity.

(2) Injection of molten rubber into the injection cavity to obtain an injection blast on the core.

(3) the injection core moves backwards towards the injection cavity with the injection moulded material

(4) The drive unit drives the blow moulding cavity assembly toward the injection moulding core located in the middle of the blow moulding cavity assembly so that a confined space is formed between the outer wall of the injection moulding core and the blow moulding cavity assembly.

(5) High pressure gas is passed through the injection core blowing port into the confined space to blow mould the injection blanks.

(6) The driving device drives the blow moulding cavity assembly to move away from the injection moulding core, so that the blow moulding cavity assembly is separated from the injection moulding core and the moulded product is picked up.

Injection blow moulding.

The machine consists of one machine with a hopper on top. On the left side is the Archimedes screw, which is used to push the material forward. In the middle, there is a heated section for melting the raw material. On the right-hand side is the mould cavity where the moulded part is formed in the cold state. The plastic component is thus placed in the hopper and the Archimedes screw then rotates, pushing the material into the heated section, where it melts and the temperature rises to such an extent at the nozzle that it rapidly enters the mould cavity, where curing is completed and the article is finally removed with the help of the extraction pin.


3. Stretch blow molding.

The Stretch blow molding process refers to a blow molding process by biaxial directional stretching, stretch blow molding process is based on the development of ordinary extrusion blow molding process and injection blow molding process. The blow moulding process is based on the common extrusion and injection blow moulding processes. The blanks are first made by extrusion or injection, then treated to a suitable stretching temperature for the plastic and stretched longitudinally by internal (with a stretching mandrel) or external (with a stretching jig) mechanical forces, and transversely by compressed air blowing at the same time or later, to obtain the final product.

First, a preform similar to a test tube is manufactured using injection moulding or a similar process. The neck of the preform is completely finished, but the diameter and length of the main part is much smaller than the final product. The preform then goes through a stretching and blow moulding process. It is the technology of choice for manufacturing PET bottles.

The one-step method is where the three main processes of preform preparation, stretching and blow moulding are completed sequentially in one machine, also known as the hot preform method. The billet is the semi-finished product in the production process. The equipment can be combined in the following ways: ① by an extruder and a blow moulding machine; ② by an injection moulding machine and a blow moulding machine.

The first step is the preparation of the blanks, which are cooled and then become a semi-finished product to be processed, with specialised production characteristics. The second step provides the cold blanks to another company or another workshop for reheating, stretching and blow moulding, also known as the cold bad method. The two-step method is incomparable in terms of yield and control of process conditions and is suitable for high volume production, but consumes more energy.

Stretch blow moulding has four combinations: ① one-step extrusion stretch blow moulding for processing PVC; ② two-step extrusion stretch blow moulding for processing PVC and PP; ③ one-step injection stretch blow moulding for processing PET and RPVC; ④ two-step injection stretch blow moulding for processing PET.

The Stretch blow moulding process includes: injection moulding billet directional stretch blow moulding, extrusion billet directional stretch blow moulding, multi-layer directional stretch blow moulding, compression directional stretch blow moulding, etc.. These are all characterised by the use of bidirectional stretching at temperatures below the melting point to increase the strength of the product.

Stretch blow moulding.

Finally, we have also summarised.

There are several different methods available when considering moulding options for production purposes. Blow moulding and injection moulding are two of the most common. However, it is important to help customers understand the differences between the two before their company decides what moulding process to use.

  1. Blow moulding is designed to produce hollow, single containers, such as bottles. Injection moulding, on the other hand, is used to produce solid parts, such as helmets and other plastic products.
  2. Air is the biggest enemy of injection moulding. If air is present during the manufacturing process, air pockets or bubbles can be created. These anomalies can create weak links in the product and eventually lead to a defective and potentially discarded product. With blow moulding, air is particularly important. Blow moulding revolves around the air that is forced into the mould to push out and expand the product.
  3. Stretch blow moulding is best suited to PET bottles.

If you have any specific questions about the process outlined or would like to discuss your needs in more detail,

Please feel free to contact us directly via the website: https://www.amanmachine.com/ or email : sales3@amanmachinery.com