The key points of attention and the popularization of relevant knowledge of PET bottle embryo during injection molding

Update:22 Oct 2020

With the continuous progress of science and technology, PET bottle embryo has gradually come into our lives, and is known by more and more people. However, some people are still inadvertently familiar with it. In view of this situation, we have collected a lot of relevant information for your reference. Now we will pay attention to the "PET bottle embryo in the work of the key points and related knowledge of Science Popularization" to understand in detail.

what are the precautions for PET bottle embryo during injection molding
Pet chemical name is polyethylene terephthalate, also known as polyester. Now, gf-pet is widely used in customers, mainly in bottle embryo. The rheological property of pet in melt state is better, and the effect of pressure on viscosity is greater than that of temperature. Therefore, the fluidity of PET melt is mainly changed by pressure.

1. Treatment of plastics
Because pet macromolecules contain lipid groups and have certain hydrophilicity, the particles are relatively sensitive to water at high temperature. When the moisture content exceeds the limit, the molecular weight of pet decreases during processing, and the finished product is colored and brittle. Therefore, it is necessary to dry the materials before processing. The drying temperature is 150 ℃ for more than 4 hours, generally 170 ℃ for 3-4 hours. We can check whether the data is completely boring by air shooting method. Generally, the proportion of recovered materials should not exceed 25%, and the recovered materials should be completely boring.
2. Selection of injection molding machine
Because the stable time of PET after melting point is short, and the melting point is high, it is necessary to choose the injection system with more temperature control sections and less self conflict heat generation during plasticization. Moreover, the practical component of finished product (water containing material) should not be less than 2 / 3 of the injection volume of the machine. Based on these requirements, Funeng has developed a series of pet special plasticizing systems in recent years. The clamping force should be greater than 6300 T / m2.
3. Mold and gate planning
PET bottle embryo is usually molded by warm runner mold. There should be a heat insulation board between the mold and the mold plate of the injection molding machine, with a thickness of about 12 mm, and the heat insulation board must be able to accept high pressure. It is necessary to exhaust enough to prevent overheating or fragmentation. However, the depth of the exhaust port should not exceed 0.03mm, otherwise flash will occur.
4. Melt temperature
It can be measured by air shooting method. The enhanced gf-pet can be set at 290-315 ℃.
5. Injection speed
Generally, the injection speed should be fast, which can prevent premature solidification during injection. But too fast, high shear rate makes the material fragile. The firing is usually finished in 4 seconds.
6. Back pressure
The lower the better, to prevent wear. Generally, it does not exceed 100bar. It is generally unnecessary to use.
7. Dwell time
Do not use long dwell time to prevent molecular weight reduction. Try to prevent the temperature above 300 ℃. If the shutdown time is less than 15 minutes. If it is more than 15 minutes, it should be cleaned with viscosity PE, and the barrel temperature should be reduced to PE temperature until the machine is started again.

8. Precautions
(1) the recovered material should not be too large, otherwise it will easily occur in the blanking place and affect the plasticization.
(2) if the mold temperature control is not good or the material temperature control is not proper, it is easy to produce "white fog" and not clear. The mold temperature is low and even, the cooling speed is fast, and the finished product is bright with less crystallization.
What is PET bottle embryo
1、 Application scope of PET bottle embryo automatic cutting nozzle machine:
At present, plastic bottles are widely used in our daily life. Plastic bottles are formed by blow molding of bottle embryos by blow molding machines. Bottle embryos directly affect the quality and production capacity of plastic bottles. Bottle embryos are currently produced by injection molding machines. There are water nozzles at the tail of injection moulded embryos. Blow molding can only be carried out by cutting off this nozzle. At present, most of the nozzles are cut manually At present, the labor cost is rising and the labor force is difficult to recruit, which greatly affects the production efficiency and quality of plastic bottle embryo.

In view of the above shortcomings of the existing plastic bottle embryo production process, Hexiang Automation Technology Co., Ltd. has invented a fully automatic injection molding, reclaiming and cutting nozzle machine device, which can greatly improve the production efficiency, reduce the production cost, and completely solve the problem of labor difficulty.
2、 Technical scheme of automatic water cutting machine for bottle embryo:
The invention relates to a fully automatic production method of plastic bottle embryo, which comprises an injection molding machine, a manipulator, a special fixture, a bottle embryo automatic nozzle cutting machine and a conveyor. The bottle embryo automatic cutting nozzle machine is placed on the side of the injection molding machine, the manipulator is placed on the upper part of the injection molding machine, the special fixture is installed on the manipulator, and the conveyor is placed on the left side of the automatic bottle embryo cutting nozzle machine. After injection molding of plastic bottle embryo, the product is taken out by manipulator and special fixture, and put into the automatic cutting nozzle machine for cutting nozzle, and the qualified products are put into the conveyor.
3、 Features of the machine are as follows
It has the advantages of low investment, high efficiency, labor saving, automatic operation and wide versatility. It is suitable for all types of manipulators and can be used for most bottle embryos.
4、 Functions of automatic water cutting machine for bottles:
It includes transverse mechanism, moving mechanism, shear nozzle mechanism, discharging fixture, rack and waste hopper.
The material transfer mechanism and the shear nozzle mechanism are driven by the transverse mechanism, which is driven by the motor. After the transverse mechanism moves to the mechanical origin, the manipulator takes the product from the injection molding machine and puts it into the discharging fixture. The transverse mechanism drives the shear nozzle mechanism to the bottle embryo nozzle position, and cuts the nozzle in turn. After the shearing, the material transfer mechanism moves the bottle embryo position downward to take out the bottle embryo to the original point On the conveyor, the injection molding manipulator can also be selected to take out the bottle embryo to the conveyor, and the nozzle material falls into the waste hopper by its own weight, and the cycle operation stops at the specified capacity.