Screw Type Thermoplastic Injection Molding Machine For Pet Preform Wide Mouth

1. Treatment of plastics
Because PET macromolecule contains lipid group, it has certain hydrophilicity. Particles are sensitive to water at high temperature. When the moisture content exceeds the limit, the molecular weight of PET decreases and the products become colored and brittle.
Therefore, before processing, the material must be dried, its drying temperature is 150 C, more than 4 hours; generally 170 C, 3-4 hours. It can be used to check whether the material is completely dry. The proportion of recycled PET bottle blank should not exceed 25%, and the recycled PET bottle blank should be thoroughly dried.

2. Selection of Injection Molding Machine
Because of the short time of stabilization after melting point and the high melting point of PET, the injection system with more temperature control section and less self-friction heat generation during plasticization should be selected, and the actual weight of the product (water-containing orifice) should not be less than 2/3 of the injection volume of the machine.

3. Mould and gate design
PET bottle embryo is usually formed by hot runner mould. It is better to have a heat insulation plate between the mould and the injection machine template. The thickness of the heat insulation plate is about 12 mm, and the heat insulation plate must be able to withstand high pressure. Exhaust must be sufficient to avoid local overheating or fragmentation, but the exhaust outlet depth should not exceed 0.03mm, otherwise it is easy to produce flash.

4. Melt temperature
It can be measured by air irradiation method, ranging from 270 to 295 degrees C, and the enhanced grade GF-PET can be set to 290 to 315 degrees C.

5. Injection speed
Generally, the injection speed should be fast to prevent premature coagulation during injection. But too fast and high shear rate make the material fragile. The projectile is usually completed in 4 seconds.

6. Back pressure
The lower the better, so as not to wear. Usually not more than 100 bars, usually do not need to use.

7. Residence time
Do not use too long detention time to prevent the molecular weight from decreasing, and try to avoid the temperature above 300 C. If the shutdown time is less than 15 minutes, only air-jet treatment is required; if it is more than 15 minutes, it should be cleaned with viscous PE, and the barrel temperature should be lowered to PE temperature until the machine is restarted.

8. Notes
(1) Recycled materials should not be too large, otherwise, it is easy to "bridge" at the discharging site and affect plasticization;
(2) If the mould temperature is not well controlled or the material temperature is not properly controlled, it is easy to produce "white fog" and opaque; if the mould temperature is low and uniform, the cooling speed is fast and the crystallization is small, the product is transparent.

NINGBO HAIJIANG MACHINERY MANUFACTURING CO.,LTD., situated in Ningbo Yinzhou Investment & Innovation Center, coversa land of more than 50,000M2.It was established in 1992 and now employs a staff of more than 500 people. with CE and ISO9001

Haijiang Company is a hihg-tech enterprise specialized in manufacturing injection molding machine that mainly covers dozens of speci?cations with injection shot of 45-2,0000g and mold clamping force of 400-15,000KN. Based on the marrow of the trade gained and through years' accumulation, the company has made constant innovation to ensure the machine quality.Parts built into the machines of defferent mold locking forces are all processed under specialized management. HJF series injection molding machines are developed by Haijiang Company on the basis of a collection of the advantages assimilated from all world famous brand machines with optimized design realized by CAD/CAM/CAPP where technical problems such as noise of the entire machine and low energy dissipation are removed and thus the design quality of products is secured. The company adopts advanced equipment and technology and applies scientific management. Besides, it has introduced high-precision full automatic CNC machines fitted with imported electric and hydraulic parts, which have tremendously improved the accuracy and steadiness of the whole machine. Its present products such as HJK and KJF series and widely applied in the electronic, automobile and civil industries.
In order to participate in competition in the world market,the company has clustered a group of high quality technical and managerial personnel with innovative spirit by means of optimized combination fo personnel. The company faces the society and users by acting on the principle of pursuit for ?rst class and sincere service. We will appreciate friends from all circles who have given their concern and support to Haijiang machines with first class products and first class after service.