The Primary Differences between Injection Moulding & Blow Moulding


The plastics manufacturing industry extensively makes use different types of moulds to craft the plastic bottles, jars, air-tight containers, and the numerous other such items that we use in our day to day lives. The two main types of molding techniques that are used for creating these various items are: Injection Moulding and Blow Moulding.

There are separate companies that make the molding equipment that are used by the plastic industry. They are moulding machines manufacturers. Whether they are injection moulding companies in South Africa or in India, they supply their machines to the pet plastic suppliers in South Africa and in India respectively. They also supply these machines to many other players that form a part of the plastic industry. Anyway, let’s get back to our main topic. The primary differences between injection moulding & blow molding are as follows:

The Product

This is possibly the most obvious difference between the two molding techniques. The products manufactured through the injection technique include solid objects such as plastic cups, lids, bottle caps, etc., while the products manufactured by employing the blow technique are hollow objects such as water bottles, fuel tanks, etc.

The Process

In the injection molding technique, as the name suggests, melted resin is injected into a hollow mold until it’s full. The mould used in it is subjected to high pressure to keep it together and to ensure that every part of its interior is properly filled with the resin. The machine size and production cost in this technique are influenced by the tonnage pressure needed to keep the moulds together.

In the blow moulding technique, on the other hand, air is filled in a plastic tube after sufficiently heating the tube, which results in a balloon like formation referred to as a parison. Following this, a mould is clamped around the inflated plastic tube or parison to trap it and provide it the desired shape. The machine size and production cost in this technique are affected by the weight of the plastic shot inserted into the mold.

The Moulds

High precision match between the mould halves is crucial for the success of the injection moulding process. In this process, 90% of the battle is won if perfect moulds are created. Due to the high level of precision requirement in the injection technique, it is relatively dearer than the blow technique.

In the blow molding process, there is comparatively more flexibility in terms of the mould halves. Here, the role of the mould is only 50%, while the rest 50% depends on the factors such as wall thickness, air leaks, and streaks.

If you are also a plastic products manufacturer who is looking for reliable and affordable molding solutions, you may contact Acme Disys, a leading manufacturer and supplier of Preform and Cap Molds.


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