Two-Stage Blow Molding Machine Introduction

Two-stage blow molding machine is an advanced device widely used in the field of plastic bottle production, especially suitable for the manufacturing of PET bottle. Its technological process divides the production of plastic bottles into two independent and continuous stages: injection molding of the preform and blow molding of the bottle body. Two-stage blow molding machine greatly enhances production efficiency and the stability of product quality by separating the injection molding and blow molding processes. This technology not only adapts to diverse bottle designs but also facilitates automated operation, reducing labor costs and meeting the modern packaging industry’s demand for high efficiency and high quality.With the continuous development of the plastic packaging market and the advancement of technology, two-stage blow molding machine is also constantly being innovated and upgraded. Modern machine is equipped with high-precision temperature control

system and servo control technology, which can precisely control the heating and expansion process of preforms, ensuring size and quality of each bottle meet strict standards. Meanwhile, the concept of energy conservation and environmental protection design is widely applied in manufacturing. For instance, high-efficiency and energy-saving heater and intelligent production management system are adopted to reduce energy consumption and the rate of defective products. In addition, two-stage blow molding machine, through modular design and a flexible mold changing system, enables the production line to quickly switch between products of different specifications and styles, meeting the market’s demand for personalized and customized packaging.

Working Process of Two-Stage Blow Molding Machine

Raw material preparation

Injection Molding

Preheating

Blow molding

Raw material preparation
The raw materials for the two-stage bottle blow molding machine mainly include PP, PE, PET and other materials. These materials need to undergo thorough screening, blending, feeding, melting and other treatments before entering the production process. In order to ensure the quality and grade of raw materials, strict testing and control are required.
Injection Molding
During the injection molding process, raw materials which have been strictly selected and mixed need to be injected into the injection molding machine. After being heated, melted and plasticized, they are injected into the mold for molding. This process requires strict control of parameters such as the temperature, pressure and injection speed of the machine.
Preheating
After injection molding, the molded products need to be preheated. During this process, the temperature of the preform will be uniformly raised, especially in the thickness area of the preform wall. The purpose of this process is to enhance the plasticity and flexibility of the molded products and prepare them for subsequent blow molding.
Blow molding
During the blow molding stage, the preheated molded products need to be placed into the blow molding machine for blow molding. The machine heats the molded products and then stretch them, blow air to eventually shape them into various forms of bottles. This process requires precise control over all parameters of the machine and the quality of the formed products.

Two-Stage Blow Molding Machine Overview

Two-Stage Blow Molding Machine Installation Cases

Two-Stage vs. Single-Stage Blow Molding Machine Compariso

Two-Stage Blow Molding Machine

Single-Stage Blow Molding Machine

Two-Stage Blow Molding Machine
Principle: Steps are completed by two machines.
Step 1: Injection molding of the preform
The preform is produced by injection molding machine and can be cooled, stored or transported.
Step 2: Blow molding
The preform is preheated and then sent to the blow molding machine for stretching and blow molding to form plastic bottle.

Features: The preform and the blow molding process are separated, offering high production flexibility. Preform can be mass-produced and supplied, making it highly suitable for large-scale centralized production.

Single-Stage Blow Molding Machine
Principle: Steps are completed by one machine.
Raw materials are fed into the machine at one time and the entire process of injection molding of the preform, preform heating and blow molding is completed in one machine.

Features: This method eliminates the need for preform transportation and storage, reduces energy consumption. It is more suitable for the production of small batches, multiple varieties and high-precision bottle shapes.

Advantages of Two-Stage Blow Molding Machine

manufacturing-process-of-plastic-bottles

Flexible process: Two-stage blow molding machine allows the injection molding and blow molding processes to be carried out separately. The parameters of injection molding and blow molding can be adjusted as needed to meet the production requirements of different products.

High product quality: As the injection molding and blow molding processes are carried out separately, the process parameters of the two stages can be optimized respectively, improving the molding accuracy and surface quality of the product.

High production efficiency: The injection molding machine and the blow molding machine can operate independently without interfering with each other, enhancing the overall production efficiency.

Low equipment investment cost: Compared with single-stage blow molding machine, two-stage blow molding machine is more economical in terms of equipment investment and is suitable for small and medium-sized factories.

Raw Materials of Two-Stage Blow Molding Machin

PET (Polyethylene Terephthalate)

PP (Polypropylene)

PC (Polycarbonate)

PE (Polyethylene)

The most commonly used preform raw material is PET, which has high transparency, good strength and excellent food safety performance. It is suitable for manufacturing mineral water bottles, carbonated beverage bottles and edible oil bottles. In addition, PP, PC and PE are also the raw materials used for two-stage blow molding machine. PP has good high-temperature resistance and is suitable for hot filling bottles, which is often used in food packaging, medicine bottles and chemical bottles. PC has high-transparency and high strength, manufacturing high-temperature resistant or impact-resistant bottles. PE has good flexibility and strong chemical resistance. It is used for certain soft bottles or special packaging.