Working principle and characteristics of PET one-step blow molding machine


PET bottle blowing machine is mainly used for blowing P […]

PET bottle blowing machine is mainly used for blowing PET plastic material. It is completed through a series of actions such as feeding, heating, conveying, stretching, and clamping. The one-step PET bottle blowing machine blowing process is a two-way stretch process In this process, the PET chain is bidirectionally extended, oriented and arranged, thereby increasing the mechanical properties of the bottle wall, improving the tensile, tensile, and impact strength, and has excellent air tightness. Although stretching helps to increase strength, it should not be overstretched, and the stretch-inflation ratio must be controlled well. Blowing is performed between the glass transition temperature and the crystallization temperature, usually between 90 and 120 degrees. In this interval, the PET exhibits a highly elastic state, and becomes a transparent bottle after being rapidly blown and cooled and shaped.

Blow molding process includes: stretch-blow once-blow twice. The three actions are very short, but they must be well coordinated, especially the first two steps determine the overall distribution of the material and the quality of the blowing. Therefore, it is necessary to adjust: stretching start timing, stretching speed, pre-blowing start and end timing, pre-blowing pressure, pre-blowing air flow, etc. If possible, it is best to control the overall temperature distribution of the preform, inside the preform The temperature gradient of the outer wall. During the rapid blowing and cooling process, induced stress occurs in the bottle wall. For inflatable beverage bottles, it can resist internal pressure and has advantages, but for PET bottle blowing machines, it is necessary to ensure that it is fully released above the glass transition temperature.

Pet blowing machine features

The drying tunnel is separated from the bottle blowing platform, which reduces the time of mold opening, improves the blowing efficiency, and increases the output at the same time.

1. The compact exterior design reduces space, reduces production costs, and enhances competitiveness.

2. Automatic operation system.

3. Advanced control system, simple and convenient control panel.

4. Independent and simple linear operation system.

5. Unique heating system, precise temperature control and easy adjustment.

6. Unique storage device.

7. The cooling system of the PET blow molding machine can achieve the ideal cooling effect.

PET raw material characteristics:

PET raw material is milky white or light yellow, highly crystalline polymer, smooth and shiny. It has excellent physical machine functions in a wide temperature range, and the long-term use temperature can reach 120℃. The electrical insulation is relatively good, and the motor can still work normally under high temperature and high frequency, but the corona resistance is poor, creep resistance, fatigue resistance, friction resistance, and dimensional standards are all very good.

During the blowing process of the bottle blowing machine, if the parameters are not set properly, the blown bottle will have various problems, the most common one is the bottom of the bottle dent

The common causes of bottle bottom depression are as follows:

1, the bottom of the bottle is insufficient

Solution: lower the heating temperature at the bottom of the bottle

2, the bottom heating temperature is too high

Solution: Adjust the heating temperature of the bottom of the bottle to a suitable temperature. Different manufacturers have slightly different temperature adjustments. When adjusting the temperature, you can consult the blowing machine manufacturer

3, insufficient pre-blowing

Solution: Extend the pre-blowing time

4. Insufficient high pressure

Solution: increase the amount of high-pressure blowing