How to Choose the Right PET Injection Molding Machine

PET injection molding machine is a very widely used type of injection molding machine nowadays, and choosing the right PET injection molding machine can bring very big benefits. So how do you choose the right PET injection molding machine?Kebida, as a top PET injection molding machine manufacturer, takes you through how to choose a PET injection molding machine.

What is PET injection molding machine

PET injection molding machine is the same as any other injection molding machine such as PE, PP, etc. The difference is that it does not make the final product, but rather the bottle blanks. When you inject a plastic object, your mold has an external and internal shape, with the space between the two filled with plastic to form the object. With PET bottles, this is difficult because you can't take the internal shape out of it. So preforms are injected, which are spiral tops and hollow finger-like shapes.

PET bottle preform injection molding machine is suitable for the molding of bottle preforms for products such as mineral water, carbonated beverages, fruit juices, edible oils, pharmaceutical cans and lotions, and cosmetic packaging containers.

Features of PET injection molding machine

1. It can be used to produce various types of PET bottle blanks, such as: water bottles, hot-fill bottles, oil bottles, wide-mouth bottles and large bottle blanks.

2. Complete product supporting, can provide full machine dehumidification, drying, pumping, freezing, mold, hot runner and other automatic peripheral equipment planning.

3. Special injection structure design, convenient for plastic molding of PET raw materials.

4. Linear potentiometers are used for injection and mold closing, which can precisely control the stroke with high precision.

5. With screw cold storage start limit, line break detection, insulation and other functions, which is conducive to the stability of the screw molding.

6. High dimensional stability of bottle blanks and low defective rate.

8 points for choosing PET injection molding machine

According to the characteristics of PET plastic, we can choose PET injection molding machine from the following aspects.

1. Screw. Screw length-diameter ratio, the design of special PET screw, the general plastic screw length-diameter ratio of about 18-22, PET screw length-diameter ratio is generally more than 1:24, the greater the length-diameter ratio of the better plasticizing ability.
2. Mold space. From the size of the mold to determine the machine's large column distance, mold thickness, mold size and the minimum size of the template is appropriate to confirm whether the mold can be placed. The width and height of the mold should be less than or at least one side should be less than the inner distance of the large column; the width and height of the mold should be within the range of the template size; the thickness of the mold should be between the mold thickness of the injection molding machine; the width and height of the mold should meet the minimum mold size recommended for PET injection molding machine. 
3. Product removal space. The mold and the finished product should determine whether the mold opening stroke and the mold holding stroke are sufficient to allow the finished product to be removed. The opening stroke should be at least twice the height of the finished product in the opening/closing direction; the clamping stroke and clamping force should be sufficient to eject the finished product.
4. Clamping force. The product and plastic determine the clamping force tonnage of the machine. When the raw material is injected into the mold cavity at high pressure, a clamping force is generated, so the clamping unit of the injection molding machine must provide sufficient clamping force to keep the mold from being opened. The clamping force requirement is calculated as follows. 

   The projected area of the finished product in the direction of the opening and closing of the mold, derived from the external dimensions of the finished product.  

   The clamping force = the projected area of the finished product in the direction of the opening/closing die (cm2) × the number of cavities × the pressure in the die (kg/cm2); 

   The clamping force of the machine should be greater than the clamping force, and for insurance purposes, the clamping force of the machine should be more than 1.17 times the clamping force. 

   After the initial determination of the clamping unit specifications and the general determination of the PET machine tonnage, the following steps must be performed to confirm which injection unit screw diameter is more in line with what is required. 

5. Full shot. From the weight of the finished product and the number of cavities, determine the required "shot volume" and select the appropriate "screw diameter". Calculation of the weight of the finished product should take into account the number of cavities (a mold of several cavities); for the sake of stability, the shot volume should be more than 1.35 times the weight of the finished product, that is, the weight of the finished product should be within 75% of the shot volume. 
6. Shot well. PET plastics are judged by the "screw compression ratio" and "injection pressure" and other conditions. PET plastic needs better plasticizing ability and suitable screw compression ratio design, in order to have a better molding effect, so in order to make the finished product shot better, in the choice of screw also need to consider the plasticizing needs and compression ratio issues.
7. Increase the storage motor. PET plastic easy sticky material, molding temperature and other reasons, the need for a larger screw torque, often choose a larger than ordinary machine two or more than two levels of storage motor to meet the needs of the machine.
8. Increase the power system. Storage motor increase screw speed reduction, in the increase in storage motor at the same time also increase the power system to ensure more stable operation of the machine, shorten the product cycle time.

In addition, you need to consider the mold waterway to improve the cooling efficiency of the mold, PET molds are equipped with special PET water divider block.

Where to find PET injection molding machine manufacturer

• Online platform

  Online platforms such as Alibaba and Made in China are ideal places for different PET injection molding machine manufacturers to market to their customers.

  Manufacturers can usually offer you different prices and after-sales services.

  PET injection molding machine on B2B platforms

  When searching on these sites, you must make sure that you choose a manufacturer and not a distributor or trader.

  Also, do not start a transaction with a specific manufacturer until you have verified their credentials.

  The advantage of having a large number of manufacturers on these sites is that you can negotiate or select the right manufacturer to build your PET injection molding machine.

  You also have the opportunity to negotiate the price of the product.

  The disadvantage is that you are vulnerable to scams, which means you must be careful before deciding on a specific manufacturer.

• Sourcing Agents

  Many sourcing agents in China are aware of the different PET injection molding machine manufacturers in China.

  They know the production capabilities and pricing of these manufacturers.

  These are important specifications that your sourcing agent can help you with when looking for a manufacturer.

  Sourcing agents can also save you the hassle of finding a reliable manufacturer, as they usually have a ready-made list for you to choose from.

  The main limitation of using a sourcing agent is the high cost of finding a manufacturer.

• Trade shows and trade fairs

  Whenever a China trade show is held in your country or in China, you should expect Chinese manufacturers to showcase their products.

  This allows you to interact with different manufacturers and ask them about different aspects of their manufacturing process.

  The advantage of this approach is that you can meet face-to-face with a specific manufacturer.

  This allows you to negotiate with the manufacturer on different specifications.

  Crucially, once you have reached an agreement with a particular manufacturer, you will need to visit their premises before you can start production.

• Google Search

  A direct search for the keyword PET injection molding machine manufacturer will produce a large number of independent websites that manufacture such injection molding machines.

  However, in general, the top rankings are for some internationally known brands. Chinese injection molding machine manufacturers have been relatively late to the search engine. You need to scroll back a few pages and you will find a large number of quality Chinese injection molding machine manufacturers.

List of Excellent PET Injection Molding Machine Manufacturers in China

Conclusion

Choosing a good and suitable PET injection molding machine can bring you a lot of benefits. We hope you find this article helpful.

If you have further questions, please contact us and talk to our professional technical team.

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