learning about gas assisted injection molding.


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What is gas assisted injection molding?


Technical form of injection moulding, gas assisted injection moulding uses plastic and Nitrogen gas to fill an injection mould under high pressure. The benefit of the gas assisted injection molding is the ability to create hollow parts in a specific time of injection molding machine.


The process behind the Gas assist injection molding.

The fundamental process of gas injection moulding is quite similar to injection molding.

  • The extruder barrel of the injection molding machine results in the melting away of RAW palletized plastic material which is eventually injected to the injection mould to fill it up to 70%.
  • Towards the second end, pressurized gas is filled in the mould in order to cool down everything injected.
  • This results in hardening up of the molten plastic and completing the process.
  • The pressure released from the gas is injected like a regular injection molded part.


gas assisted injection molding header


The process eventually fills a plastic injection molded part in a hollow form. Blow moulding for rotational moulding is the only leftover method to achieve one whole hollow part during the process of single manufacturing in plastic. Talking about the blow moulding process, it is a highly capital intensive manufacturing procedure that is used in bottle making and rotational moulding. The cycle time is measured in minutes and not in seconds.


Here is a simple animated video that explains the gas injection molding.

Video credits : Miles Manufactured Products, Inc ( Please do let us know via our contact form if this video to be removed from our content)




Advantages of gas assisted injection molding

 There are a wide range of advantages delivered by gas assisted injection molding procedure in comparison to normal injection molding.

  • It has the ability to alter hollow parts which results in major weight saving.
  • It also helps the companies to save a lot on material cost.
  • The hollow interior reduces and removes the flow lines as the plastic is put under constant pressure from the gas.
  • In certain scenarios, it cools faster and the hollow eventually doubles the surface area that results in the hardening and cooling of the part. This reduces the shrinkage as the pressurized gas hollows the thicker walls.

Disadvantages of gas assisted injection molding

There is a whole range of drawbacks when it comes to gas channel injection molding procedure. In case the design guide is a failure, it sure shot to create a lot of problems. The first and the most important complexities regarding the expenses to set up an ordinary injection moulding. If the normal tooling price of injection moulding is expensive. for you, gas assisted injection molding will definitely give you a heartbreak. Further, introduction of gas in a molding mix should be precisely tracked, managed and controlled. In the absence of proper experience from the operators and technicians, the molding process can result in huge losses once it goes wrong.


You need to control the gas very well because it contributes to the variable was thickness specifically in the tight corners where one wants to avoid reaching it. If you are really not sure about a gas injection moulding gas design system, you must get it properly designed from the experts.


Gas assisted injection molding is widely used to produce handles, TV frames and several products. There are very less disadvantages of using the gas assisted injection molding manufacturing process. The slow cooling of the mould and post-war page remains among the unwanted outcomes of the process.


How to overcome the problems related with gas assist injection molding?


In order to resolve the problems, there is Reverse gas injection moulding process invented. The process comes with dual special units in which one includes an overflow buffer and the other one includes the error unit. The overflow buffer has a role play in reducing the material and the air unit it is used for faster cooling of the mould.


There have been several experiments done to verify the efficiency of the reverse gas injection molding process. As a result, it was discovered that the efficiency of the process was twice better than the rest of conventional methods.

People generally go for gas assisted injection molding because it results in a better manufacturing efficiency and production. In general, thermoplastics have to be heated in order to get molded and melted. After they reach a certain temperature, they can be injected into a closed metal mould. After the cooling takes place, the material shrinks away. In order to overcome this problem, more material is injected to the cavity in normal circumstances.

In order to eliminate all the hassles and drawbacks of normal injection moulding, gas injection moulding process results in better molding warping and changing of dimensions.

The external gas injection provides better surface definition of the component. It also results in weight and cost reduction with several combined benefits.

One can achieve a better dimensional control and enhanced service quality as the major benefit of using gas injection. Sink marks resulting because of local thin and thick deviation in the permanently eliminated and more evenness is produced.

Here is the Brief History of Plastic Injection Molding and it’s evolution

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