The basic principles of Plastic Injection Moulding

The process of Plastic Injection Moulding or PIM dates back to the 19th century. Although the methods, materials and machines have changed with time, the fundamental production principles remain the same. The products made from PIM are things that we use in our day-to-day lives. It is one of the most common methods used by injection moulding manufacturers to produce mass volumes of identical plastic products.

The process of injection moulding is not a complicated one. The entire process begins from thousands of tiny plastic pellets that are tossed into a giant rotating screw. As the pellets travel along, they are subjected to temperatures of around 400 degrees Fahrenheit. Due to the friction and force provided by the screw, the pellets slowly liquify and travel to a valve. This is where the molten plastic is forced under high pressure into a custom-made mould.

When the mould is completely filled, it goes into the next step called the holding phase. Clamps on the mould maintain the holding pressure until the plastic cools to a solid-state. This stage of the process is further aided by coolants that surround the mould. The cooled product is ejected from the mould and moves on to the finishing stages such as decoration, sub-assembly and packaging.

Also Read: Plastics components - Industrial Benefits

Closeup view of plastic injection moulding machine

The Pros of Plastic Injection Moulding as Given by Injection Moulding Manufacturers

India plays an eminent role in plastic production and consumerism, with approximately 20 million metric tonnes of plastic being produced annually. Increased plastic usage has fueled the demand and growth of injection moulding products. Manufacturers state that there are more advantages that attribute to the popularity of PIM, which we have listed below:

Efficient mass production
Depending on the size and complexity of the mould, per cycle time can be anywhere between 10- 150 seconds. With this incredible speed, an injection moulding machine can produce a lot of products within a very limited time gap.
Complex customized designs
Compared to other techniques, PIM allows manufacturers to produce intricately designed products with highly precise detailing. The process of high heat and pressure on the moulds allows for a larger amount of details to be imprinted on to the product.
Low labour costs
The plastic injection moulding machine is completely automated, requiring only a sole operator to control and handle the process. This helps to significantly reduce overhead costs. While the machine itself may be a huge investment, when it comes to production, the cost per part is very less.
High production output
Once the machine is installed and gets going, thousands of identical products can be made before the machine requires maintenance. A well-maintained mould tool tends to have a very long lifespan and thus boosts the output.

Choice of raw material
Injection moulding manufacturers can choose from a wide range of raw materials to produce products of high quality.
Antistatic plastic
Thermoplastic rubber
Chemical resistant plastic
Flame retardant material like Poly Phenylene Oxide
Polymer resins
Uniform colour control
With colour compounding and masterbatch colouring, it is possible to produce a thousand products in the same uniform colours.
Production consistency
Injection moulding is a consistent process where the same mould is used to produce a thousand identical products. This is a massive advantage for manufacturers who are looking to produce part reliability in high volumes.
Customized textures and finishes
Injection moulding can be made with customized finishes and textures that will show on the moulding. Logos, letters, names and numbers can also be engraved in the tools.

Low wastage
There is almost nil wastage with injection moulding. Any unused waste that comes from the sprue and runners can be recycled and reused.

The Cons of Injection Moulding

With injection moulding, the pros outweigh the cons. Apart from the few points listed below, there isn’t much to complain about plastic injection moulding.

High investment

Part limitations

Lengthy setup time

PIM deserves a special budget allotment because of its up-front costs that manufacturers will incur right from the designing and testing stages. The mould tool itself requires manpower, material and machining hours to make.

Very large products like automotive parts require enormous mould tools, which can be very expensive to make. Besides, the use of steel or aluminium can limit the chances of changing the designs.

Due to the complexity of the process and the tooling, getting the machine ready for the next product can take a considerable length of time to be set up. The process of getting rid of all the previous material and fixing smaller parts can cost time and money.

Techplaastic Industries: The leading plastic moulding manufacturers in India

Techplaastic is an industry leader in manufacturing injection moulded parts, products and components for a wide variety of industrial sections in India. We are armed with an infrastructure that is designed to cater to the requirements at the most reasonable prices. For more details, contact us @ +919840247472.