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The difference between injection blow moulding and extrusion blow moulding plastic bottle
- Mar 27, 2018 -

The difference between injection blow moulding and extrusion blow moulding plastic bottle


Comparison of plastic bottles for injection blow moulding and extrusion blow moulding Products The difference between the two methods of extrusion blow molding and injection blow moulding plastic bottle is: In injection molding, the mould used to form the plastic bottle body should include male mould and yin mold. By injecting the plastic melt into the mold cavity under high pressure and opening the cavity, the male mould must be removed from the mould to top out the bottle body. And in the extrusion blow molding, to use extrusion head molding.

   Blow molding mold Mainly by the two halves of the mold, generally do not need to male mould, with injected compressed air to inflate the parison.

Extrusion blow molding characteristics of injection and extrusion compared to the characteristics of extrusion blow moulding:


(1) Blow molding machinery (especially blow molding) of low cost, such as molding the same product, blow molding machinery cost about 1/3 or 1/2 of injection molding machinery, product production cost is also low.


(2) Blow molding, the Parison is under the lower pressure through the extrusion head molding and in the low-pressure (most of 0.2~1.0 MPa) under the blowing, thus the product residual stress is small, tensile, impact, bending and the environment, such as a variety of strain performance is high, with good performance.

In injection molding, the plastic melts in the high-pressure (15~140 MPa) through the mold runner and gate, which will lead to uneven stress distribution.


(3) Blow molding grade plastic (such as PE) of the molecular weight than injection-grade plastic is much higher.

This blow molding product has high impact toughness and high environmental stress cracking performance, which is very advantageous to the production of large capacity plastic bottles.


(4) as the blow molding mold only by the yin Mold, it is simple to adjust the die mouth clearance or extrusion conditions can change the thickness of the bottle body, which can not accurately calculate the required wall thickness of the product is very advantageous.

For injection molding, the need to change the thickness of the product is much higher cost.


(5) Blow molding can be a thin wall thickness of products, such products can not be molded by injection method.


(6) Blow molding can be shaped complex shape, irregular and integral products. When using injection blow molding, first produce two or more pieces, through the buckle, solvent bonding or ultrasonic welding combined together.