How Much Do You Really Know About Injection Molding?

Views: 17     Author: Site Editor     Publish Time: 2022-04-19      Origin: Site

Injection molding is a process in which similar products are made out of plastic in large volumes. These products are manufactured to cater to numerous industries, including the automobile industry, medicine, aviation, computing devices, electronic appliances, and many more.

What is Injection Molding?

The process in which molten plastic is subjected to molds left to settle is called injection molding. After some time, the final product is ready. In this process, numerous plastic components may be manufactured at a time and transported to required industries.

This process is one of the most eminent forms of production, which offers to produce plastic components used in various industries.

Types of Injection Molding

There are several kinds of injection molding, and each type has its considerations and production means; every single kind of injection molding is used to manufacture different components.

  • Thin wall molding

Thin wall molding is a kind of injection molding that is suitable for such plastic components that require thin  sided walls.

In this type of injection molding, the process is so detailed and considerable that it ensures there lies no room for any cracks or quality issues with components.

  • Gas-assisted injection molding

Injection molding is a process that starts with using molten plastic that solidifies on cooling. In several cases, these plastic components may have some loopholes upon cooling. There might be specific spaces, cracks, and deformation present.

Gas-assisted injection molding passes gas through the molds filled with molten plastic. This helps eliminate any deformity on cooling and finishes the components' surface.

The gas, usually nitrogen gas, is considered in that aspect, and it passes through the hollow cavities of the molds that eliminate all the chances of damage.

  • Metal injection molding

The process of injection molding is limited to the extent of just plastic. Metal may also pass through this process. Several industries like the cellular industry may need such components made with metal rather than plastic. 

Hence, here the role of metal injection molding is sufficiently essential and helps produce numerous parts commonly used. However, this industry is a very innovative one.

  • Liquid silicone injection molding

In the case of the usual injection molding process, the plastic is introduced through the injection molds, and it has a stiff and robust component that is not flexible in any way. 

However, many such industrial requirements also exist where a component that may tolerate high temperature and is flexible is needed. In this case, liquid silicon is molded, and the desired output is achieved.

  • Reaction injection molding

The demand for foam plastic is also very significant worldwide in different industries, derived from the reaction injection molding process. In this procedure, the highly reactive forms of plastics are mixed. They polymerize and turn out to be in the foam state, which is then used.

Advantages and disadvantages of injection molding

A prevalent method of developing several plastic components is called injection molding. It is popular with metal components and has certain advantages and disadvantages that comprise the following.


  • Produces high volumes

One of the most important reasons for choosing injection molding is that it produces bulk components at once. This helps save time and costs and hence proves to be a very suitable approach for several businesses.

Most industries considering having components made out of injection molding usually need their parts manufactured in bulk. This bulk production helps them save costs, and they have stock at their end to cater to their production runs.

  • Handles complex layouts

No matter how complex the design of a component is, injection molding allows producing it with uniformity. The proper detailing and cuts are the same in every element as a finished product.

Several businesses have very complex needs for every part because of the nature of that component, and this aspect is very well catered to through injection molding.

  • Strength of components

The process of injection molding comprises a considerable level of strength. These components are solid that comes out as a result of injection molding. The main reason is that one single layer is considered for the process, and hence it ensures that there are no loopholes.

Due to its ability to produce strengthened parts, injection molding also allows other businesses to rely on it in the context of having accurate and quality-oriented details.

  • Controlled flexibility and rigidity

There is a different requirement for each component to be either flexible or rigid. The process of injection molding is versatile enough to cater to both forms. Hence, soft and flexible plastic parts are formed, and hard ones are also manufactured.

If you consider the example of the medical field, you will notice that the thickness and strength of test tubes, beakers, and other laboratory equipment are very rigid. However, considering the flexibility of oxygen masks and drips are very soft. 

These two forms of components are used in one field, but this aspect is vital to consider to offer the right final products.

  • Less wastage

The wastage of plastic is a significant concern that harms the environment. However, injection molding is one such procedure where there is very little or no wastage of plastic. 

The molten form is poured into molds, and hence nothing is lost during the process.

Businesses that are dependent on injection molding for their components may also be at peace that they won't end up buying such parts that damage the environment. 

This procedure reduces plastic waste and does not emit any pollution.

  • Savings on labor cost

Injection molding is mainly carried out with high-tech machinery that is highly automated, and hence the need to employ much labor is reduced. Therefore this helps in saving labor costs.

When the labor costs are low for the injection molding manufacturers, the affordability for the end businesses will also be a suitable one that helps them draft realistic budgets for their final products.

  • Versatile material choice

Choosing to opt for injection molding has a massive advantage that there are so many materials choices available for the production of components. No matter what kind of product and what kind of hardness, flexibility, or thickness is needed, it caters to this aspect well.

Some industries require flexible and soft components, some products are such that they need complex and rigid structures, and some need the foamy touch. All these requirements are catered to through injection molding due to the availability of numerous material choices.


As much attention is given to the advantages, there should be an eye on the disadvantages of injection molding, which matters in several ways.

  • High initial investment

The costs involved in the initial setup of injection molding are very high. The tools and machinery amount to be costly, and hence the setup requires a lot of capital invested.

  • Not suitable for small batches

Injection molding is a process that is suitable only if you want to get massive volumes produced. It does make small batches as well but is not as cost-effective for them as it is for the larger volumes.

  • Design restrictions exist

One commonly faced problem with injection molding is that specific complex designs might not be created in terms of components. It may require a highly technical design team, and if you don't have it, you might struggle in the designing process.

  • Testing time is longer

After the machinery is set up, businesses carrying out injection molding need to spend a lot of time on the testing process. Unless the testing process is completed and correct parts are ready to be manufactured, the business may not start earning.

Common Materials Used for Injection Molding

The injection molding process may be carried out to produce several components and parts, and the most popular materials used for this process may include the following.

  • Acrylonitrile butadiene styrene

This material is used in injection molding and produces numerous components based on thermoplastics like keyboards, pipes, and automobile parts.

  •  Nylon

Nylon is also one of the prevalent forms of materials used in injection molding, and through this, it produced fishnets, car tires, and insulators for electrical appliances.

  • High-density polythene

High-density polythene is considered a strength-oriented and hard form of plastic used in injection molding. Through the process, it produces bottles for different purposes and is used to make toys and plastic flower pots.

  • Low-density polythene

Low-density polythene is also used in food-grade materials. Cling wraps and food-grade crockery and cutlery based on disposable making are manufactured through injection molding using these materials.

  • Polycarbonate

Injection molding uses polycarbonate to manufacture plastic products that need to be hard and transparent at the same time. It is commonly used in making bullet proof glass, helmets, and particular hardware used in telecommunication.

  • Polypropylene

Polypropylene is a highly suitable material in the packing industry and is mainly used in packaging food and medicine. The chemicals of this material do not mix with the food and medicine packed, and hence it proves to be a very suitable choice in this case.

  • Polyoxymethylene

Polyoxymethylene is a material with a crystalline structure and is a harder one to choose. All such products that require a finish of crystalline structure followed by a hard structure are made using this choice. 

Eyeglass frames, lock systems, bearings, and certain knife parts may be made using this material.

How does Injection Molding work?

The injection molding process is relatively straightforward. The injection molding machine is filled with the desirable plastic, which melts by heating. This melted plastic is then transferred to the desired molds through the machine's nozzle. 


As soon as the liquid plastic in the molds is cooled down, it solidifies and is ready to use. However, the final product has to be molded out of the mold after taking solid form.

Applications of Injection Molding

Injection molding is used in various industries. Several things around us have been composed of several such components of plastic formed by passing through the process of injection molding. Some of its common applications are discussed below:

Automotive Components

The automobile industry depends on the injection molding process for several things. 

This may include the interior as well as the exterior of the automobiles. Even the operation areas under the hood of a car may have several such components made with injection molding.

Covers for the cylinder and oil cavities in the hood of a vehicle are made using injection molding. The interior and exterior, door handles, dashboard, air vents, door panels, bumpers, grillers, and several parts are made with this method.

Medical Devices

Injection molding covers several areas of the medical field. Several such small and big, hard and flexible medical components come into being through this process.

 A few of such applications in the medical industry may consist of beakers, laboratory equipment, catheters, canulas, test tubes, surgical tools, and many more.

Consumer Electronics

In day-to-day life, several electronics form to be a part of our usage and needs. These electronic products may also have certain parts made using injection molding.

These may comprise the router cases, battery cases, enclosures used for mobile phones, security panels used at home, laptop covers, keyboards, and many more.


Injection molding is a popular and commonly considered approach and methodology by numerous businesses. It is a highly dependable industry that other companies rely upon their components. 

We can see that numerous parts used in the automobile industry, medical field, electronics, household essentials, and food industry are highly dependent on this process.

The advantages of injection molding tend to attract numerous businesses, and it fulfills the requirements of such businesses cost-effectively.

FAQs About injection molding 

There might be specific questions on your mind that may bother you regarding injection molding; these answers may help you resolve your queries.

Is injection Molding Environmentally Friendly?

Not really, Injection molding has no excessive waste production or emissions released that may cause damage to the environment. 

The latest and innovative machinery used in this process offers a suitable approach to reduce waste and negative impacts on the environment due to the manufacture of different parts.

How accurate is injection molding?

Injection molding is such a precise process that there lies no chance of ambiguity in the accuracy of its production. It uses the best machines that are wholesome on their own, and hence the final product is much finished.



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